Photobiocatalytic Strategies for Organic Synthesis

Biocatalysis has revolutionized chemical synthesis, providing sustainable methods for preparing various organic molecules. In enzyme-mediated organic synthesis, most reactions involve molecules operating from their ground states. Over the past 25 years, there has been an increased interest in enzymatic processes that utilize electronically excited states accessed through photoexcitation. These photobiocatalytic processes involve a diverse array of reaction mechanisms that are complementary to one another. This comprehensive review will describe the state-of-the-art strategies in photobiocatalysis for organic synthesis until December 2022. Apart from reviewing the relevant literature, a central goal of this review is to delineate the mechanistic differences between the general strategies employed in the field. We will organize this review based on the relationship between the photochemical step and the enzymatic transformations. The review will include mechanistic studies, substrate scopes, and protein optimization strategies. By clearly defining mechanistically-distinct strategies in photobiocatalytic chemistry, we hope to illuminate future synthetic opportunities in the area.

Enantioselective Deaminative Alkylation of Amino Acid Derivatives with Unactivated Olefins

Herein, we report the first Ni-catalyzed enantioselective deaminative alkylation of amino acid and peptide derivatives with unactivated olefins. Key for success was the discovery of a new sterically encumbered bis(oxazoline) ligand backbone, thus offering a de novo technology for accessing enantioenriched sp³-sp³ linkages via sp³ C-N functionalization. Our protocol is distinguished by its broad scope and generality across a wide number of counterparts, even in the context of late-stage functionalization. In addition, an enantioselective deaminative remote hydroalkylation reaction of unactivated internal olefins is within reach, thus providing a useful entry point for forging enantioenriched sp³-sp³ centers at remote sp³ C-H sites.

MicroRNA-126 Attenuates the Effect of Chemokine CXCL8 on Proliferation, Migration, Apoptosis, and MAPK-Dependent Signaling Activity of Vascular Endothelial Cells Cultured in a Medium with High Glucose Concentration

We studied the mechanisms by which microRNA-126 regulates proliferation and migration of human umbilical vein endothelial cells (HUVEC) cultured in a medium with high glucose concentration and treated with chemokine CXCL8. Cell proliferation, apoptosis, and migration were analyzed by the CCK-8 assay, Annexin V-PI staining, and Transwell assay, respectively. The ratios of p-ERK/ERK, p-P38/P38, p-JNK/JNK were determined by ELISA. HUVEC cells cultured in the presence of high glucose concentration (30 mmol/ml) and treated with CXCL8 (50 ng/ml) demonstrated more intensive proliferation, migration, and p-ERK/ERK, p-P38/P38, and p-JNK/JNK ratios and significantly lower apoptosis rate than control cells (high glucose, no treatment) and cells treated with CXCL8 and transfected with microRNA-126-mimic. Thus, microRNA-126 regulates proliferation and migration of HUVEC cells cultured in the presence of high glucose concentrations and treated with CXCL8 through inhibition of MAPK signaling pathway.

[Molybdenum cofactor deficiency type B manifested as Leigh-like syndrome: a case report and literature review]

Objective: To explore the phenotypes and genotypes of molybdenum cofactor deficiency type B (MoCD-B) manifested as Leigh-like syndrome. Methods: The clinical data, laboratory tests, neuroimaging and gene results of one patient diagnosed as MoCD-B at Beijing Children's Hospital and Hebei Children's Hospital in December 2018 were collected. Related literature was searched and reviewed at Wanfang Data Knowledge Service Platform, China National Knowledge Infrastructure and PubMed (up to September 2020) by using terms "MOCS2" "molybdenum cofactor deficiency" "Leigh-like syndrome,MOCS2" "molybdenum cofactor deficiency, Leigh-like syndrome". The phenotypes and genotypes of MoCD-B were summarized. Results: A 7 months and 14 days old boy with the chief complaint of "cough for 6 days, abnormal posture for 4 days and fever for 2 days" was admitted to Hebei Children' Hospital on December 2018. His abnormal posture presented as opisthotonos accompanied with dysphagia, without seizures. His previous psychomotor development was described as normal. He was born at term after an uneventful pregnancy to non-consanguineous parents. Blood test showed a slightly increased lactic acid and a significantly decreased uric acid. Urine metabolism test showed an obviously increased xanthine and hypoxanthine. Brain magnetic resonance imaging showed hyperintense signal on T2 weighted image and fluid attenuated inversion recovery in bilateral globus pallidus and pedunculus cerebri. The patient was diagnosed with Leigh-like syndrome. No obvious improvement was achieved after cocktail therapy and symptomatic treatment. The whole exome sequencing showed that the patient carried a homozygous variant of MOCS2 gene, c.19G>T(p.Val7Phe), which was a previously reported pathogenic site in the literature and could cause MoCD-B. His parents carried a heterozygous variant respectively. A total of 41 MoCD-B cases with MOCS2 gene variants were collected through literature review and our study, among which 30 cases had full medical records. The onset ages of 23 (77%) cases were in neonate, manifesting with severe encephalopathy, including neonatal-onset intractable seizures, developmental delay, laboratory abnormalities included very low levels of serum and urinary uric acid, increased urinary levels of xanthine and hypoxanthine. Cranial imaging showed cerebral atrophy, cystic encephalomalacia, etc. The onset ages of 7 patients varied from 5 months to 23 years. Four cases had normal psychomotor development before disease onset. Neurological disorders appeared acutely or exacerbated after external triggers and all of them had basal ganglia involvement. Among the 30 cases, 3 cases had a relatively milder phenotype with the ability of brief communication and walking without or with support. Conclusions: Molybdenum cofactor deficiency is a rare disease. Most cases had severe phenotypes and poor outcomes, but some cases may have mild phenotype. MoCD-B caused by MOCS2 gene variants may manifest as Leigh-like syndrome with a normal psychomotor development before the trigger of infection strike. Hypouricemia, xanthinuria and hypoxanthinuria can be indicators of the disease. The presence of MOCS2 gene variants would confirm a final diagnosis.

Site-Selective 1,2-Dicarbofunctionalization of Vinyl Boronates through Dual Catalysis

A modular, site-selective 1,2-dicarbofunctionalization of vinyl boronates with organic halides through dual catalysis is described. This reaction proceeds under mild conditions and is characterized by excellent chemo- and regioselectivity. It thus represents a complementary new technique for preparing densely functionalized alkyl boron architectures from simple and accessible precursors.

Copper mediated C(sp2)-H amination and hydroxylation of phosphinamides

Copper mediated C(sp2)-H amination and hydroxylation of arylphosphinic acid are accomplished by adopting phosphinamide as the directing group. This method is distinguished by its wide substrate scope and excellent functional group tolerance, thus allowing for the rapid preparation of organophosphorus compounds in organic synthesis.

Site-Selective Catalytic Deaminative Alkylation of Unactivated Olefins

A catalytic deaminative alkylation of unactivated olefins is described. The protocol is characterized by its mild conditions, wide scope, including the use of ethylene as substrate, and exquisite site-selectivity pattern for both α-olefins and internal olefins, thus unlocking a new catalytic platform to forge sp³-sp³ linkages, even in the context of late-stage functionalization.

[A multicenter study of reference intervals for 15 laboratory parameters in Chinese children]

Objective: To establish comprehensive laboratory reference intervals for Chinese children. Methods: This was a cross-sectional multicenter study. From June 2013 to December 2014, eligible healthy children aged from 6-month to 17-year were enrolled from 20 medical centers with informed consent. They were assessed by physical examination, questionnaire survey and abdominal ultrasound for eligibility. Fasting blood samples were collected and delivered to central laboratory. Measurements of 15 clinical laboratory parameters were performed, including estradiol (E2), testosterone(T), luteinizing hormone(LH), follicle-stimulating hormone(FSH), alanine transaminase(ALT), serum creatinine(Scr), cystatin C, immunoglobulin A(IgA), immunoglobulin G(IgG), immunoglobulin M(IgM), complement (C3, C4), alkaline phosphatase(ALP), uric acid(UA) and creatine kinase(CK). Reference intervals were established according to central 95% confidence intervals for reference population, stratified by age and sex. Results: In total, 2 259 children were enrolled. Finally, 1 648 children were eligible for this study, including 830 boys and 818 girls, at a mean age of 7.4 years. Age- and sex- specific reference intervals have been established for the parameters. Reference intervals of sex hormones increased gradually with age. Concentrations of ALT, cystatin C, ALP and CK were higher in children under 2 years old. Serum levels of sex hormones, creatinine, immunoglobin, CK, ALP and urea increased rapidly in adolescence, with significant sex difference. In addition, reference intervals were variable depending on assay methods. Concentrations of ALT detected by reagents with pyridoxal 5'-phosphate(PLP) were higher than those detected by reagents without PLP. Compared with enzymatic method, Jaffe assay always got higher results of serum creatinine, especially in children younger than 9 years old. Conclusion: This study established age- and sex- specific reference intervals, for 15 clinical laboratory parameters based on defined healthy children.

[Research progress in maxillary sinus mucosal disease associated with maxillary sinus floor lifting]

Maxillary sinus augmentation is an effective procedure to gain bone height for implant placement in an atrophic posterior maxilla. But maxillary sinus diseases are prevalent in patients scheduled for sinus lift procedures. The presence of these diseases may increase the difficulties in performing the surgery and the risk of developing postoperative complications. This paper summarizes and introduces the common maxillary sinus mucosa diseases related to maxillary sinus augmentation.

Site-Selective Ni-Catalyzed Reductive Coupling of α-Haloboranes with Unactivated Olefins

A mild, chemo- and site-selective catalytic protocol that allows for incorporating an alkylboron fragment into unactivated olefins is described. The use of internal olefins enables C-C bond-formation at remote sp³ C-H sites, constituting a complementary and conceptually different approach to existing borylation techniques that are currently available at sp³ centers.

Nickel-Catalyzed Umpolung Arylation of Ambiphilic α-Bromoalkyl Boronic Esters

A nickel-catalyzed reductive arylation of ambiphilic α-bromoalkyl boronic esters with aryl halides is described. This platform provides an unrecognized opportunity to promote the catalytic umpolung reactivity of ambiphilic reagents with aryl halides, thus unlocking a new cross-coupling strategy that complements existing methods for the preparation of densely functionalized alkyl-substituted organometallic reagents from simple and readily accessible precursors.

[Clinical and genetic characteristics of children with Leigh syndrome]

Objective: To investigate the clinically and genetic characteristics of children with Leigh syndrome. Method: Patients with clinically diagnosed Leigh syndrome(LS)in the department of Neurology, Beijing Children's Hospital from January 2013 to February 2016 underwent the mitochondrial DNA (mtDNA) and nuclear DNA (nDNA) detecting with next generation sequencing (NGS) technology. The clinical data of gene confirmed cases were retrospectively collected and analyzed. The differences in the onset age, clinical manifestations, lactic acid level and MRI results between the mtDNA variation and nDNA variation were compared and analyzed.t test, Chi-square test and Fisher's exact test were used for statistical analysis. Result: Thirty-five cases were diagnosed by gene detection, including 20 males and 15 females. The median onset age was 1 year (ranging from the neonatal period to 4.4 years old). The age of onset within 2 years accounted for 74%(26 cases). The onset age of initial symptoms, including developmental delay, developmental regression, and seizures, were 6 (4, 12) months, 12 (8, 14) months, and 6 (1, 23) months respectively. The onset age of ptosis, extrapyramidal symptoms and ataxia were 26 (18, 44) months, 28 (23, 40) months and 28 (19, 35) months, respectively. There were significant differences in the onset age between the three groups (H=21.919, P=0.01). Within the 35 cases, 29 were manifested with developmental delay (83%), 26 with dystonia (74%), 18 with growth retardation, 15 with myasthenia, 13 with developmental regression, 11 with dysphagia, 10 with feeding difficulties, 4 with skeletal dysplasia, and 2 with digestive tract symptoms; nystagmus and respiratory abnormalities were observed in 9 cases respectively; extrapyramidal symptoms, peripheral nerve injury, ptosis, seizures were observed in 8 cases respectively; and ataxia, ophthalmoplegia and hypertrichiasis were found in 5 cases respectively.The blood lactic acid was measured in 32 LS patients, within which 23 cases (72%) had increased results; 8 out of 11 cases who underwent were cerebrospinal fluid lactic acid test had increased results. The results of neuroimaging revealed that all the patients were involved in the brainstem and (or) basal ganglia, of whom 27 (77%) had brainstem involvement, 24 (69%) had basal ganglia involvement. Thirteen out of 14 patients who had medulla oblongata involvement had nDNA variation; while 7 out of 8 patients with cerebellar involvement had nDNA variation. Genetic etiology was confirmed in all patients, among whom there were 17 cases (49%) with mtDNA mutation, including 8993T>C/G (n=5), 14487T>C (n=4), 13513G>A (n=2), 9176T>C, 10158T>C, 3697G>A, 10191T>C, 14459A>G and 11777C>A (n=1) respectively. Remaining 18 cases(51%) had nDNA mutation, including SURF1 gene(n=10), PDHA1 gene(n=3) and one case each of NDUFV1, NDUFAF6, NDUFAF5, NDUFS1 and COQ7 genes. In this study, 27 types of mutations were founded, 15 of which had not been previously reported. Respiratory chain gene mutations have been found in 31 cases(89%); 3 cases had PDHc gene mutations, and 1 case had other mutation. Conclusion: LS usually occurs in infants. The most common primary symptoms are age-dependent abnormal movements, ocular symptoms, and seizures. Respiratory chain defects is the most common causes of LS.SURF1 is the most common variation, followed by 8993T>C/G, 14487 T>C and 13513G>A mutation.

Identification of monodentate oxazoline as a ligand for copper-promoted ortho-C-H hydroxylation and amination

The use of a weakly coordinating monodentate directing group for copper mediated ortho-hydroxylation and amination reactions allows for the identification of an external oxazoline ligand as a promoter.

Th17/Treg cell expression in children with primary nephritic syndrome and the effects of ox-LDL on Th17/Treg cells

To investigate the role of T-helper cells/Treg (Th17/Treg) and morbidity factors related to primary nephritic syndrome (PNS) in children, as well as the influence of ox-low density lipoprotein (ox-LDL) on Th17/Treg expression in children with PNS. To clarify the pathogenesis of PNS in children, 50 children with PNS treated in our hospital were enrolled in the study group. Additionally, 20 healthy children who came to our hospital for physical examination during the same period were enrolled in the control group. Th17 and Treg cells in children belonging to the two groups were detected by flow cytometry; the numbers of Th17/Treg cells in peripheral blood mononuclear cells at different concentrations of ox-LDL were detected simultaneously. Ox-LDL can affect the number of Th17/Treg cells in peripheral blood mononuclear cells, and both cell types decreased with increasing concentration of ox-LDL, with the numbers being significantly lower in the control group. However, the decrease in the number of Th17 cells was statistically insignificant (P > 0.05), whereas the decrease in Treg cells was more obvious and statistically significant (P < 0.05). The effect of ox-LDL the number of Treg cells was stronger than that on Th17 cells. We concluded that the imbalance of Th17/Treg cells influenced by high and low ox-LDL concentrations in children with PNS might be the immunological basis of the disease.

Cu(II)-Mediated C(sp(2))-H Hydroxylation

A Cu(II)-mediated ortho-C-H hydroxylation using a removable directing group has been developed. The reaction exhibits considerable functional group tolerance. The use of O2 as an oxidant is crucial for the reactivity. Water is also found to significantly improve this reaction.

Cu(II)-catalyzed coupling of aromatic C-H bonds with malonates

A new Cu(II)-catalyzed oxidative coupling of arenes with malonates has been developed using an amide-oxazoline directing group. The reaction proceeds via C(sp(2))-H activation and malonate coupling, followed by intramolecular oxidative N-C bond formation. A variety of arenes bearing different substituents are shown to be compatible with this reaction.

Cu(OAc)2-catalyzed coupling of aromatic C-H bonds with arylboron reagents

Cu-catalyzed coupling of aryl C-H bonds with arylboron reagents was accomplished using a readily removable directing group, which provides a useful method for the synthesis of biaryl compounds. The distinct transmetalation step in this Cu-catalyzed C-H coupling with aryl borons provides unique evidence for the formation of an aryl cupperate intermediate.

Cu(II)-mediated ortho C-H alkynylation of (hetero)arenes with terminal alkynes

Cu(II)-promoted ortho alkynylation of arenes and heteroarenes with terminal alkynes has been developed to prepare aryl alkynes. A variety of arenes and terminal alkynes bearing different substituents are compatible with this reaction, thus providing an alternative disconnection to Sonogashira coupling.

Exceedingly fast copper(II)-promoted ortho C-H trifluoromethylation of arenes using TMSCF₃

The direct ortho-trifluoromethylation of arenes, including heteroarenes, with TMSCF3 has been accomplished by a copper(II)-promoted C-H activation reaction which completes within 30 minutes. Mechanistic investigations are consistent with the involvement of C-H activation, rather than a simple electrophilic aromatic substitution (SE Ar), as the key step.

The human ether-a'-go-go related gene (hERG) K+ channel blockade by the investigative selective-serotonin reuptake inhibitor CONA-437: limited dependence on S6 aromatic residues

Diverse non-cardiac drugs adversely influence cardiac electrophysiology by inhibiting repolarising K(+) currents mediated by channels encoded by the human ether-a-go-go-related gene (hERG). In this study, pharmacological blockade of hERG K(+) channel current (I(hERG)) by a novel investigative serotonin-selective reuptake inhibitor (SSRI), CONA-437, was investigated. Whole-cell patch-clamp measurements of I(hERG) were made from human embryonic kidney (HEK 293) cells expressing wild-type (WT) or mutant forms of the hERG channel. With a step-ramp voltage-command, peak I(hERG) was inhibited with an IC(50) of 1.34 μM at 35 ±1°C; the IC(50) with the same protocol was not significantly different at room temperature. Voltage-command waveform selection had only a modest effect on the potency of I(hERG) block: the IC50 with a ventricular action potential command was 0.72 μM. I(hERG) blockade developed rapidly with time following membrane depolarisation and showed a weak dependence on voltage, accompanied by a shift of ≈ -5 mV in voltage-dependence of activation. There was no significant effect of CONA-437 on voltage-dependence of I(hERG) inactivation, though at some voltages an apparent acceleration of the time-course of inactivation was observed. Significantly, mutation of the S6 aromatic amino acid residues Y652 and F656 had only a modest effect on I(hERG) blockade by CONA-437 (a 3-4 fold shift in affinity). CONA-437 at up to 30 μM had no significant effect on either Nav1.5 sodium channels or L-type calcium channels. In conclusion, the novel SSRI CONA-437 is particularly notable as a gating-dependent hERG channel inhibitor for which neither S6 aromatic amino-acid constituent of the canonical drug binding site on the hERG channel appears obligatory for I(hERG) inhibition to occur.

Ru(II)-catalyzed ortho-C-H amination of arenes and heteroarenes at room temperature

The Ru(II)-catalyzed ortho-C-H amination directed by a weakly coordinating amide auxiliary with O-benzoyl hydroxylamines at room temperature has been achieved. This reaction is compatible with heterocycles including pyrazole, thiophene, benzothiophene, furan, benzofuran, and indole.

Structural properties of the proton translocating complex of the clathrin-coated vesicle

The clathrin-coated vesicle proton pump is a representative member of the new class of endomembrane proton ATPases that share an inhibitor profile which distinguishes them from classic F1F0 and E1E2-type proton pumps. The coated vesicle proton pump is a large (530 kDa) heteroligomer composed of eight polypeptides with molecular masses of 116, 70, 58, 40, 38, 34, 33 and 17 kDa. The 200-fold purified enzyme catalyses ATP-generated proton pumping when reconstituted in liposomes composed of pure lipids. Subunit function has been determined by partial reaction analysis of subunit and subcomplex activities. The isolated 17 kDa subunit, when co-reconstituted with bacteriorhodopsin, forms a dicyclohexylcarbodiimide-inhibitable proton channel. Selective removal of the 116 kDa subunit transforms the proton ATPase from a Mg2+-activatable to a Ca2+-activatable ATPase. Subsequent dissociation and reconstitution of subunits reveals that the 70, 58, 40 and 33 kDa components are required, in composite, to form a functional ATP-hydrolytic core, and that no single subunit or subcomplex deficient in these subunits can catalyse ATP hydrolysis.

Culture of smooth muscle cells from guinea pig mesenteric lymphatic vessels

The in vitro culture of lymphatic smooth muscle cells (SMCs) is a crucial step in studying their function and involvement in disease. Yet there is no efficient approach available so far because of the difficulties posed by the small size of most lymphatic vessels. We present a simple yet efficient method for isolating and culturing SMCs of collecting lymphatic vessels from guinea pig mesenteric tissue. In our approach, thin lymphatic vessels were digested twice from adventitia to media to release SMCs, which were then cultured by traditional methods. The lymphatic SMCs we cultured did not exhibit contact inhibition and demonstrated typical SMCs characteristics under light microscope, electron microscope and by immunohistochemical studies. This method is applicable to the culturing of lymphatic SMCs from other organs and provides useful materials for physiological and pathological lymphatic studies.

[Clinical evaluation of pulpotomy in the treatment of deciduous teeth with deep dentine caries]

OBJECTIVE

To study the curative effect of pulpotomy in the treatment of deciduous teeth with deep caries.

METHODS

45 deciduous molars with deep caries from 3 8 years old children were selected at random. Pulpotomy was performed on these treated teeth. Clinical examination and X-ray films for the treated teeth were taken to follow up all the teeth at 6 months, one year and two years respectively after treatment.

RESULTS

At one year after treatment, 45 cases were followed up, the rate of success in clinical examination and in X-ray photographs both were 100%. While at two years after treatment, 42 cases were followed up and 3 cases were lost, the rate of success in clinical examination was 95% and the rate of success in X-ray photographs was 88%. The reasons of the failure were internal absorption and pulpitis followed by fracture and exfoliation of the obturators in the treated teeth.

CONCLUSION

Pulpotomy in deciduous teeth with deep caries was a reliable and effective method. It is necessary to follow up the treated teeth by X-ray at regular intervals after treatment.

Naphthol-ASBI phosphate as a preferred substrate for tartrate-resistant acid phosphatase isoform 5b

Tartrate-resistant acid phosphatase (TRAP) isoform 5b is a potential serum marker for osteoclastic activity. Biochemical assays for serum TRAP activity with para-nitrophenylphosphate (pNPP) have low specificity for bone because of hydrolysis by unrelated nontype 5 TRAPs of blood cells and by related isoform 5a. Our purpose was to increase the specificity of TRAP assay for osteoclastic activity by using naphthol-ASBI phosphate (N-ASBI-P) as a substrate for serum type 5 TRAP activity and heparin as an inhibitor of isoform 5a. TRAP activity in individual and pooled sera of normal subjects and patients with endstage renal disease (ESRD) and rheumatologic diseases was quantitated using pNPP and N-ASBI-P as substrate at pH 5.5 and 6.1. For some experiments, heparin (23U/ml) was added as a specific inhibitor of isoform 5a activity. Isoforms 5a and 5b were separated from serum pools by cation exchange chromatography and identified by nondenaturing polyacrylamide gel electrophoresis (PAGE). N-ASBI-P was selectively hydrolyzed by TRAP isoform 5b. TRAP assays with pNPP and N-ASBI-P correlated only in ESRD sera, which contained primarily isoform 5b. The two assays did not correlate in normal or rheumatic sera with significant amounts of 5a. Heparin inhibited isoform 5a activity approximately 50% but had little effect on isoform 5b activity. Biochemical assay of serum TRAP activity can be made specific for isoform 5b by using N-ASBI-P and heparin. This method can be adapted to simple microplate biochemical or immunochemical assays. This simplified method for assessment of osteoclastic TRAP 5b activity warrants a detailed investigation in diseases of bone metabolism.

Tartrate-resistant acid phosphatase isoform 5b as serum marker for osteoclastic activity

BACKGROUND

Tartrate-resistant acid phosphatase (AcP) 5b is a marker of osteoclastic activity and bone resorption. Immunoassays for serum TRAcP may lack sensitivity and specificity because of the presence of non-bone isoform 5a. The purpose of this study was to isolate the serum isoforms, quantify their disease-related expressions, and test an improved immunoassay for TRAcP 5b.

METHODS

We separated TRAcP isoforms chromatographically from pooled sera of healthy, rheumatoid arthritis (RA) and endstage renal disease (ESRD) subjects. TRAcP isoforms were identified by electrophoresis and quantified by biochemical and immunochemical assays. Serum TRAcP activity in healthy, RA, and ESRD cohorts was assessed at pH 5.5 and 6.1, and compared with bone alkaline phosphatase (BAP) and N-telopeptides of type I collagen (NTx).

RESULTS

TRAcP isoforms 5a and 5b were present in all sera; 5b was identical to osteoclastic TRAcP. In serum from healthy subjects, 5a accounted for 87% of the enzyme protein but only 55% of the activity. In RA, both isoforms were increased two- to threefold in protein, but their specific activities were subnormal. In ESRD, only 5b was abnormal, being increased fivefold in protein and threefold in activity. In RA sera, TRAcP activity did not correlate with either BAP or NTx. In ESRD sera, TRAcP activity correlated with BAP and NTx only when measured at pH 6.1.

CONCLUSIONS

All sera contained both TRAcP isoforms 5a and 5b, but only 5b was present in bone. TRAcP isoform expression was variable in different diseases. Measurement of TRAcP activity at pH 6.1 improves the specificity of immunoassay for isoform 5b.

[Study on adriamycin-porous tricalcium phosphate ceramic drug delivery system and its drug release test in vivo]

OBJECTIVE

To manufacture adriamycin-porous tricalcium phosphate (A-PTCP) ceramic drug delivery system (DDS) as a possible method for bone defect treatment after bone tumor operation.

METHODS

A-PTCP DDS was made from putting adriamycin into PTCP. Thirty rabbits were divided randomly into group A(24 rabbits) and group B(6 rabbits). A-PTCP was implanted in the greater trochanter of the right femur in group A. Adriamycin were injected into veins in group B. Muscle around A-PTCP and plasma were taken out at different period. Adriamycin concentrations in muscle and plasma were measured by high performance liquid chromatography (HPLC).

RESULTS

A-PTCP could gradually release adriamycin over 10 weeks. Adriamycin concentrations in the muscle were higher than that in plasma.

CONCLUSION

A-PTCP may be a new method for repairing bone defects after bone tumor operation.

Electrophoretic study of tartrate-resistant acid phosphatase isoforms in endstage renal disease and rheumatoid arthritis

The objective of this study was to identify the isoform, type-5a or type-5b, responsible for increased tartrate-resistant acid phosphatase (TRAP) activity in endstage renal disease (ESRD) and TRAP protein in rheumatoid arthritis (RA). We studied 24 sera each from healthy, ESRD and RA subjects. Type-5 TRAP activity and protein were quantitated by immunoassays. Isoform expression was determined by computerized imaging of non-denaturing polyacrylamide gels (PAGE) stained for TRAP activity. Other biochemical markers included: intact parathyroid hormone (iPTH), total and bone-specific alkaline phosphatase (TAP, BAP), N-telopeptides of type-I collagen (NTx), and free pyridinoline (Pyd). Isoform 5a was normal in both ESRD and RA. Isoform 5b was elevated in ESRD only. Serum TRAP activity correlated with both isoforms 5a and 5b in RA, but only with 5b in ESRD. TRAP protein assays did not correlate with PAGE assays for 5a or 5b. TRAP activity, but not protein, correlated with BAP and NTx in RA sera. Both TRAP activity and protein correlated with iPTH, TAP and Pyd in ESRD sera. Increased TRAP activity in ESRD was due to increased osteoclastic isoform 5b and related to bone turnover. Increased TRAP protein in RA was suspected, but not proven, to be isoform 5a and not related to bone turnover. Heterogeneity of serum TRAP and preferential expression of isoforms has clinical significance in different diseases including ESRD and RA.

[Induction of osteointegration of rabbit mandibular central fissure with guided tissue regeneration]

OBJECTIVE:To observe the effect of guided tissue regeneration (GTR) on induction of ostegenesis in developmental bone clefts,and provide a basis for the use of GTR to repair bony clefts in cleft lip and palate patients.METHODS:The e-PTFE membrane was placed on the labial and lingual sides of the rabbit mandibular central fissure.A radiological and pathological study was performed to determine the healing of the fissure integration.RESULTS:The results showed that the bony cleft was completely integrated 4 weeks after placement of the barrier membrane.CONCLUSION:GTR is an effective approach to reconstruct bony cleft,and is likely to be used in repair of alveolar cleft and cleft palate.

Comparison of effects of MPTCP and PTCP ceramics implanted for the treatment of bone defects in rabbits

The magnetic porous tricalcium phosphate (MPTCP) and porous tricalcium phosphate (PTCP) ceramic cylinders were implanted into right and left bone defects of rabbits' radii in order to determine the utility of the MPTCP ceramics. Based on naked eye inspection, light and scanning electron microphotography, roentgenography, quantitative histological measurement of new bone formation and anti-break test for a period of 5 months. The results showed that the two kinds of ceramics were biocompatible with human tissue. MPTCP ceramics could induce more new bone formation than PTCP ceramics. Treatment of fractures with synthetic calcium phosphate ceramics and magnetic fields were discussed.

New bone formation in the in vivo implantation of bioceramics. A quantitative analysis

Two kinds of synthetic biomaterial, porous tricalcium phosphate (PTCP) and magnetic porous tricalcium phosphate (MPTCP) ceramic granules were implanted in rat femur. In the period of 4 months, the assessment of serial histological sections, scanning electron microphotographs and quantitative analysis of bone formation in the sections showed that both ceramics are biocompatible and degradable in vivo. More new bone formation occurred in the MPTCP group. Endochondral ossification was seen in both groups. The quantitative analysis in this study is reliable, and may be suitable to the similar experimental models.

Analysis of the biocompatibility of magnetic porous tricalcium phosphate ceramics in rat femurs

A new biomaterial, magnetic porous tricalcium phosphate ceramics (MPTCP), may be used for repairing defects in bones as a substitute for bone grafting. This study was designed to examine its biocompatibility and the systemic toxicity. The ceramic sections, approximately 15.3 mg, were implanted into both proximal femurs of 10 male and 10 female albino SW rats. An equal number of male and female animals served as sham-operated controls. Implantation of MPTCP ceramics in rat femurs had no deleterious effects on body weight, organ/body weight ratio, and on blood, liver and kidney functions. Plasma levels of inorganic phosphorus were significantly elevated in rats implanted with MPTCP ceramics. Alkaline phosphatase values in plasma in the experimental group were equal to those in the control group. Photomicrographs, radiographs and scanning electron photomicrographs of the rat femurs implanted with MPTCP ceramics demonstrated excellent bone association with implants and growth of some new bone into MPTCP ceramics. In conclusion, MPTCP ceramics are biocompatible and suitable for the reconstruction of bones.

Anisakidae larvae found in marine fishes and squids from the Gulf of Tongking, the East China Sea and the Yellow Sea

Marine fishes and squids caught in the Gulf of Tongking, the East China Sea and the Yellow Sea were dissected, and many Anisakidae larvae were found in them. The larvae of Anisakis simplex (Anisakis Type I larvae), the most important causative agent of anisakiasis, was found in about 30% of fishes and squids caught in the Gulf of Tongking and in about 60% of those caught in the East China Sea and the Yellow Sea. Larvae belonging to three other genera than Anisakis--Raphidascaris or Raphidascaroides, Hysterothylacium, and Terranova (Cannon Type I)--were also detected.

Expression of the cystic fibrosis gene in non-epithelial invertebrate cells produces a regulated anion conductance

The nature of involvement of the cystic fibrosis gene product (CFTR) in epithelial anion transport is not yet understood. We have expressed CFTR in Sf9 insect cells using the baculovirus expression vector system. Reactivity with antibodies against 12 different epitopes spanning the entire sequence suggested that the complete polypeptide chain was synthesized. Immunogold labeling showed localization to both cell-surface and intracellular membranes. Concomitant with CFTR expression, these cells exhibited a new cAMP-stimulated anion permeability. This conductance, monitored both by radioiodide efflux and patch clamping, strongly resembled that present in several CFTR-expressing human epithelial cells. These findings demonstrate that CFTR can function in heterologous nonepithelial cells and lend support to the possibility that CFTR may itself be a regulated anion channel.

Isolation and reconstitution of the dicyclohexylcarbodiimide-sensitive proton pore of the clathrin-coated vesicle proton translocating complex

The clathrin-coated vesicle proton translocating complex is composed of a maximum of eight polypeptides. The function of the components of this system have not been defined. Proton pumping catalyzed by the reconstituted, 200-fold purified proton translocating complex of clathrin-coated vesicles is inhibited 50% at a dicyclohexylcarbodiimide (DCCD)/protein ratio of 0.66 mumol of DCCD/mg of protein. At an identical DCCD/protein ratio, the 17-kDa component of the proton pump is labeled by [14C]DCCD. Through toluene extraction, the 17-kDa subunit has been isolated from the holoenzyme. The 17-kDa polypeptide diminished proteoliposome acidification when coreconstituted with either bacteriorhodopsin or the intact clathrin-coated vesicle proton translocating ATPase. In both instances, treatment of the 17-kDa polypeptide with DCCD restored proteoliposome acidification. Moreover, the proton-conducting activity of the 17-kDa polypeptide is abolished by trypsin digestion. These results demonstrate that the 17-kDa polypeptide present in the isolated proton ATPase of clathrin-coated vesicles is a subunit which functions as a transmembranous proton pore.

Methyl transfer from methylcobalamin to thiols. A reinvestigation

The methyl transfer from methylcobalamin to thiols has been reinvestigated. By use of methylcobalamin selectively enriched with 13C in the methyl moiety, the methyl transfer to thiols was followed by 13C NMR. The methyl transfer occurs in aqueous mildly alkaline (pH 8-12) solution, even in the complete absence of oxygen. 31P NMR and EPR studies demonstrate that cob(II)alamin is the final corrinoid product. However, the pH dependence of the methyl-transfer reaction from methylcobalamin to beta-mercaptoethanol is consistent only with a nucleophilic displacement of the methyl group by a thiolate anion, resulting in the heterolytic cleavage of the carbon-cobalt bond. Difference visible spectroscopic measurements of the reaction mixture suggest that cob(I)alamin is formed as an intermediate.

Endemic selenium intoxication of humans in China

An endemic disease was discovered in 1961 in parts of the population of Enshi County, Hubei Province of the People's Republic of China. During the years of the highest prevalence, from 1961 to 1964, the morbidity was almost 50% in the 248 inhabitants of the five most heavily affected villages; its cause was determined to be selenium intoxication. The most common sign of the poisoning was loss of hair and nails. In areas of high incidence, lesions of the skin, nervous system, and possibly teeth may have been involved. A case is reported of a middle-aged, female hemiplegic, whose illness and death apparently were related to selenosis. Daily dietary intakes of selenium, estimated after the peak prevalence had subsided, averaged 4.99 (range 3.20 to 6.69) mg and hair and blood selenium levels averaged 32.2 and 3.2 micrograms/ml, respectively. Up to 1000x differences occurred when selenium contents of vegetables, cereals, scalp hair, blood, and urine from the selenosis areas were compared with those from Keshan disease (selenium deficiency) areas. The ultimate environmental source of selenium was a stony coal of very high selenium content (average more than 300 micrograms/g; one sample exceeded 80,000 micrograms/g). Selenium from the coal entered the soil by weathering and was available for uptake by crops because of the traditional use of lime as fertilizer in that region. This particular outbreak of human selenosis was due to a drought that caused failure of the rice crop, forcing the villagers to eat more high-selenium vegetables and maize and fewer protein foods.