Dynamic kinetic transformation of sulfinyl chlorides: synthesis of enantiomerically pure C(2)-symmetric bis-sulfoxides

Two modular and highly convergent approaches for the synthesis of both isomers of a large number of optically pure C(2)-symmetric bis-sulfoxides have been developed, and their scope and limitations have been assessed. The first one uses as intermediate diastereomerically pure C(2)-symmetric bis-sulfinate esters 6(S(S),S(S)) and 6(R(S),R(S)), obtained by dynamic kinetic resolution of ethane-1,2-bis-sulfinyl chloride 5. A single inducer of chirality, the glucose-derived DAG (diacetone-D-glucose) 1 is used for the enantioselective synthesis of both diastereomerically pure C(2)-symmetric bis-sulfinate esters, thanks to the opposite stereodirecting effect of pyridine and (i)Pr(2)NEt used to catalyze the reaction. The second approach is based on the copper-catalyzed oxidative coupling of optically pure lithiomethyl sulfoxides. Both isomers of a large number of methyl sulfoxides can be obtained in a convergent manner using (R(S))- and (S(S))-DAG methanesulfinate esters 8R(S) and 8S(S). Methanesulfinates 8R(S) and 8S(S) are also obtained in an enantioselective way by a dynamic kinetic resolution of methane sulfinyl chloride 24. The final bis-sulfoxides are obtained with enhanced enantioselectivities compared to the corresponding monomers, as a result of the Horeau effect which is operating in both approaches. A model based on the formation of pentacoordinated sulfur intermediate is proposed. This model can explain the dynamic kinetic resolution observed via Berry pseudorotations, without the commonly accepted in situ racemization of the starting material. The usefulness of the approaches is demonstrated by the preparation of complexes of Pd(II) and Ru(II) bearing bidentated chiral sulfoxides as ligands.

Exercise training-induced changes in sensitivity to endothelin-1 and aortic and cerebellum lipid profile in rats

The purpose of this work was to study whether exercise training induces changes in the lipid profile of rat aorta and nervous system and in the in vitro intrinsic responsiveness of these tissues to endothel in-1 (ET-1) treatment. The exercise program performed successfully produced the characteristic metabolic alterations of the trained state. Exercise training induced a large and significant increase in the levels of both aortic ethanolamine plasmalogens (PlasEtn) and glucosylceramides. In contrast, a decrease of aortic ceramide and cholesterol levels was evoked by exercise training. ET-1 increased PlasEtn content only in sedentary animals. An exercise-induced increase in cerebellum levels of ceramides and ceramide monohexosides was found. The cerebellum ceramide content was increased by ET-1 more noticeably in sedentary rats than in trained animals. In contrast, cerebral cortex was observed to be largely insensitive to both exercise training and ET-1 treatment. It was concluded that exercise training (i) induces changes in both vascular and cerebellar lipid profiles, the former being much more pronounced than the latter, and (ii) diminishes the aortic and cerebellar sensitivity to ET-1 action.

Alkane oxidation by a carboxylate-bridged dimanganese(III) complex

A new manganese(II) oxamato dimer possesing an unprecedented Mn2(mu-O2CR)(mu-OH2...O2CR) core has been synthesised, structurally and magnetically characterised, and used as a catalyst for the oxidation of alkanes to alcohols and ketones by ButO2H and O2 in CH2Cl2 at rt.

Location of disulfide bonds in mature alpha-L-fucosidase from pea

Fuc-9 is the mature form of a vacuolar alpha-L-fucosidase enzyme which seems to play an important role in plant growth regulation. Fuc-9 is a 202-residue protein containing five Cys residues located at positions 64, 109, 127, 162 and 169. In this study, the disulfide structure of Fuc-9 was determined by MALDI-TOF mass spectrometry (MS), with minimal clean-up of the samples and at a nanomolar scale. Two strategies, based on a specific chemical cleavage (with 2-nitro-5-thiocyanobenzoic acid and alkaline conditions) at the Cys residues and modification of Cys residues by acrylamide/deuterium labeled acrylamide alkylation, were used. Using these methods, the disulfide pairings Cys64-Cys109 and Cys162-Cys169 could be established. The advantages and limitations of our experimental approach are discussed.

Use of GnRH Analogs for Functional Protection of the Ovary and Preservation of Fertility during Cancer Treatment in Adolescents: A Preliminary Report

OBJECTIVE

Recent success in polychemotherapy (PCT) in adolescent female cancer patients has become a source of concern for specialists who also strive to preserve fertility. We studied whether gonadotropin-releasing hormone (GnRH) analogs could prevent the early onset of ovarian insufficiency postchemotherapy and protect fertility.

METHODS

The patients were divided into three groups: Control group 1 (Group A), premenarchal patients aged 3 to 7.5 years (n = 5), were not given GnRH analogs administered prior to PCT. Postmenarchal patients (Group B), aged 14.7 to 20 years (n = 12) with normal menstrual rhythm and ovulatory cycles, received treatment with GnRH analogs prior to PCT. Control group 2 (Group C), postmenarchal patients aged 15.9 to 20 years (n = 4), received PCT but no GnRH analog protection. All groups received the PCT regimens CAVPE, CVPP, ABVD, TAMO, ARA-C, and MTT. In group B, leuprolide acetate inhibition was obtained with a depot injection administered each month before and during treatment with PCT. To accelerate the timing of ovarian regression, a subcutaneous injection (0.2 mg) was administered simultaneously.

RESULTS

In Group A, patients had spontaneous menarche between the ages of 12 and 17.9 years, followed by normal menstruation and ovulatory cycles. Three patients became pregnant. After GnRH analog withdrawal, Group B patients continued with normal ovulatory cycles. Two patients became pregnant. Group C patients presented hypergonadotrophic hypoestrogenic amenorrhea.

CONCLUSION

GnRH analog treatment before and during PCT enhances ovarian function and preserves adolescent fertility. The results must be confirmed in a larger study.

Combined use of ESI-MS and UV diode-array detection for localization of disulfide bonds in proteins: application to an alpha-L-fucosidase of pea

A simplified strategy is described for the assignment of disulfide bonds in proteins of medium to high molecular mass (10-30 kDa). The method combines the use of high-performance liquid chromatography coupled to electrospray ionization mass spectrometry (HPLC-ESI-MS) and HPLC with UV diode-array detection (HPLC diode array). The denatured protein is subjected to proteolysis and the peptide mixture is divided into three fractions: (i) underivatized peptides, (ii) ethylpyridylated peptides, and (iii) reduced and ethylpyridylated peptides. The three peptide ensembles are then subjected to chromatographic and spectroscopic analysis. A systematic methodology is described to analyze the large amount of data obtained. The method was applied to the localization of disulfide bonds in alpha-L-fucosidase from pea. The two disulfide bonds were located between residues Cys64 and Cys109 and between Cys162 and Cys169, while Cys127 was free.

Dearomatizing Anionic Cyclizations of N-Benzyl-N-methyldiphenylphosphinamides. Synthesis of γ-(N-Methylamino)phosphinic Acids

The first dearomatizing anionic reaction of a phenyl ring promoted by an N-benzyl-N-methylphosphinamide group is described. The intermediate lithium species can be trapped with different electrophiles, affording tetrahydrobenzo[c]-1-aza-2lambda(5)-phospholes with excellent diastereoselectivity. The new process is a simple and very efficient entry to the stereoselective synthesis of functionalized gamma-(N-methylamino)phosphinic acids and esters.

Bochdalek's hernia in adults

Bochdalek's hernia is a congenital hernia of the diaphragm, which is manifested in the early years of life. Its diagnosis is difficult and is based on barium studies. We present an adult patient with Bochdalek's hernia who exhibited a gastric volvulus. The patient had a history of intermittent abdominal pains. In this article, we analyze the diagnostic and therapeutic procedures, laying special emphasis on the importance of early diagnosis in the prevention of complications.

Decreased bone mineral density after therapy with alpha interferon in combination with ribavirin for chronic hepatitis C

BACKGROUND/AIMS

Several thousand patients with chronic hepatitis C have been treated with interferon plus ribavirin. After observing a male patient who developed severe bone loss during this treatment, we studied skeletal status and bone mineral metabolism in patients on therapy with interferon plus ribavirin.

METHODS

Bone mineral density and biochemical bone markers were studied in 32 male patients (31-58 years old) treated for 12 months with either interferon alone (group 1; n=13) or interferon plus ribavirin (group 2; n= 19).

RESULTS

Bone mineral density was significantly lower in group 2 (0.877-0.07 g/cm2) than in group 1 (1.108+/-0.08 g/cm2, p<0.001). Likewise, T- and Z-score values were also decreased in group 2 (T: -1.95+/-0.6. Z: -1.76+/-0.51) compared with group 1 (T: 0.19+/-0.6; p<0.001. Z: 0.26+/-0.6; p<0.001). Serum and urine biochemical bone markers were normal in both groups. However, urinary calcium excretion was decreased in patients on combined therapy.

CONCLUSION

Treatment of chronic hepatitis C with interferon plus ribavirin may induce bone loss. This secondary effect should be investigated during the follow-up of these patients, since they may require therapies aimed at prevention or amelioration of these defects.

[Development and results of a screening program for COPD in primary care. The PADOC Project(Program for the Increase in the Diagnosis of COPD in Primary Care]

Several studies have shown that up to 75% of patients with chronic obstructive pulmonary disease (COPD) remain undiagnosed. Early diagnosis of such individuals will allow appropriate preventive and therapeutic measures to be prescribed. The PADOC project aimed to determine the efficacy of a COPD screening program for Spanish primary care settings. The participating primary care physicians were required to administer a spirometric test (forced expiratory volume) to all individuals who had not previously been given a diagnosis of COPD, who visited the clinic for any reason over a period of three months and who met the following enrollment criteria: a) age over 35 years and b) smoker of more than 10 cigarettes per day or ex-smoker of more than 10 packs per year. Individuals meeting the criteria for suspicion of COPD (FEV1 < 90% of predicted and FEV1/FVC < 70%) were referred to a pneumologist for confirmation of the diagnosis. One hundred ninety-four primary care physicians participated, administering 3,209 valid spirometric tests. The physicians identified 723 likely cases of COPD (22.5%). Pneumologists examined 278 patients (38.4% of the likely cases) and the final diagnosis was COPD in 153 of the 278 (55%) and asthma in 28 (10%). Therefore, 4.3% of all patients given spirometric tests received a diagnosis of COPD and 0.8% received a diagnosis of asthma. Agreement between spirometric measurements taken by the primary care physicians and those taken by pneumologists was low for FVC and FVC (%) (intra-class correlation coefficient ICC = 0.38 and 0.45, respectively) but good for FEV1 and FEV1 (%) (ICC = 0.78 and 0.67, respectively). We conclude that primary care screening for COPD is possible and would allow us to detect up to 22% of possible cases. Patient flow from one level of clinical care to another should be improved, given that most of the possible cases detected (61.6%) were not seen by the referral pneumologist. Agreement between spirometric measurements taken by primary care physicians and pneumologists was low for FVC but good for FEV1.

Twelve-month interferon-alpha therapy induces a similar sustained response in anti-HBe-positive and HBeAg-positive chronic hepatitis B patients

BACKGROUND/AIMS

We compared the response to interferon-alpha 2a in 35 patients with antibody to HBeAg (anti-HBe) and 20 patients with HBeAg in serum, and histological features of chronic hepatitis B.

METHODOLOGY

Patients were treated with 4.5-6 MU of interferon-alpha 2a, three times a week for 12 months, and followed for 30.8 +/- 13.5 additional months.

RESULTS

All of them had elevated serum levels of aminotransferases and positive test for hepatitis B virus-DNA in serum. Patients with anti-HBe-positive chronic hepatitis were older and had higher serum aminotransferase levels than HBeAg-positive patients, but no differences were seen between both groups with respect to sex, history of acute hepatitis, mode of transmission of the infection or histological appearance before interferon therapy. Serum levels of alanine transaminase became normal and hepatitis B virus-DNA undetectable by PCR at the end of therapy in 25 (71%) of anti-HBe-positive patients and in 10 (50%) of HBeAg-positive patients (P > 0.05). Although 10 (29%) of the anti-HBe-positive and none of the HBeAg-positive patients relapsed, no significant difference was seen in the rate of sustained response (43% vs. 50%, respectively). The histological improvement was similar in both groups.

CONCLUSIONS

The results of this study indicated that biochemical, virological and histological response to 12-month interferon-alpha 2a therapy was similar in patients with anti-HBe antibody than in patients with the classical HBeAg-positive of chronic hepatitis B.

Ultrastructure of the midgut and hindgut of Derocheilocaris remanei (Crustacea, Mystacocarida)

Ultrastructural features and structure of the midgut and hindgut of Derocheilocaris remanei were studied. The large endodermal midgut is differentiated into an anterior midgut and a posterior midgut separated by a conspicuous constriction. Both circular and longitudinal striated muscle bands surround the midgut, while the hindgut only presents longitudinal muscles. The limit between the midgut and the cuticle-lined hindgut is marked by a rectal valve. In cross-section, the short hindgut is triradiate and has a distinct Y-shaped lumen. The hindgut cuticular lining appears interrupted at the tip of every branch of the Y. Three different cell types are found in the midgut epithelium: basally located undifferentiated cells that give rise to the other two specialized cell types; secretory zymogen-like cells responsible for extracellular digestion and located mainly in the anterior midgut; and vacuolated cells, distributed all along the midgut and appearing to have several functions, including absorption, intracellular digestion, and nutrient transport. A single basic cell type forms the hindgut epithelium. The suggested function for the hindgut is the transport and ejection of waste products.

A hyperglycemic peptide hormone from the Caribbean shrimp Penaeus (litopenaeus) schmitti

From a crude extract of the sinus glands of the shrimp Penaeus (litopenaeus) schmitti a peptide with hyperglycemic activity in a homologous bioassay was isolated and characterized by a combination of automatic Edman degradation, enzymatic digestions, TLC of dansyl-amino acids, and mass spectrometry. Its M(r) is 8359.4 Da by MS, which coincides with the deduced sequence. Its N-terminus is free and its C-terminus is amidated. It has 6 Cys residues in conserved positions compared with other known CHHs. This is the first sinus gland hormone from an Atlantic Ocean shrimp characterized to date. It has a remarkable 90% sequence similarity to the Indo-Pacific shrimp P. (marsupenaeus) japonicus Pej-VII hyperglycemic hormone.

Use of N-butyl-2-cyanoacrylate in oral surgery: biological and clinical evaluation

N-butyl-2-cyanoacrylate based tissue adhesive, Tisuacryl, was employed as a nonsuture method for closing wounds in oral surgery. One hundred thirty patients were treated with the adhesive and 30 with suture. The surgical procedures were apicectomy, extraction of molars, and mucogingival grafting. The studied product was well tolerated by the tissue and permitted immediate hemostasis and normal healing of incisions. When Tisuacryl was used as dressing material for donor sites and mucosal ulcerations, pain relief was observed.

Novel charged [1(4)]ăzolophanes: associative behaviour revealed by electrospray ionization

Electrospray ionization mass spectrometry has been used to investigate simple multicharged [1(4)]heterophanes containing heterocyclic betaine subunits as building blocks. The formation of stable noncovalent polymolecular self-assembled structures in the gas phase is reported.

Treatment of depressed scars with a dissecting cannula and an autologous fat graft

Contemporary options for the improvement of depressed scars include scar revision with an elliptical excision, z-plasty, w-plasty, and geometric broken-line closure. Dermabrasion and laser treatment has been used to obtain a uniform skin surface. When scars are hypertrophic, intralesional steroids and silicone pressure therapy may be useful. Occasionally, scars may be adherent to the underlying fascia. The resulting depression along the length of the scar worsens the aesthetic deformity. Fat injection is an established method for treating depressions and contour deformities. We report encouraging results with the use of this fat injection technique into a pocket made with a sharp cannula in treating 30 patients with postsurgical scars that were depressed and adherent to the underlying fascia. This technique is a useful addition to the surgeon's resources when treating scars.

Platelet-activating factor modulates brain sphingomyelin metabolism

In the present study the modulatory action of platelet-activating factor (PAF) on sphingolipid metabolism in cerebral cortical slices was studied. PAF did not alter the basal levels of either sphingomyelin (SM) or ceramide. However, the SMase-elicited reciprocal alterations in SM and ceramide levels were partially prevented by the PAF treatment. The PAF effect was dose-dependent, with 10-8 m being the lowest effective concentration, and receptor-mediated as it was abolished by WEB 2086, a PAF receptor antagonist. Neither N-oleoylethanolamine (OE, ceramidase inhibitor) or d,l-1-phenyl-2-decanoylamino-3-morpholino-1-propanol (PDMP, an inhibitor of glucosylceramide synthase and the formation of 1-O-acyl ceramides) prevented the action of PAF. Therefore, the effect of PAF was unlikely to be dependent upon transformation of ceramides into glycosphingolipids, 1-O-acyl ceramides or sphingosine. Experiments with different labeled compounds ([14C]serine, [14C]arachidonate and phosphatidyl [N-methyl-3H]choline) were also performed to test whether PAF could affect the resynthesis of SM. Data obtained agree with the idea that selective pools of both choline and ethanolamine phospholipids were used as precursors for the resynthesis of SM elicited by SMase treatment. PAF itself did not evoke any variation in the lipids analyzed but always prevented the SMase-evoked alterations. Together the data suggest the interesting possibility that PAF increases the overall turnover of SM. In summary, the present data demonstrate that PAF is able to regulate the cellular ceramide levels in brain by accelerating the SM cycle.