Biomedical subjects

Feng Zhou

Publications and source records attributed to Feng Zhou.

At least 73 records · Page 4Linked to original sources

PubMed2004

[Study on the relationship between hepatitis C virus infection and sharing injection equipment, sexual behavior among injecting drug users].

OBJECTIVE: To study hepatitis C virus (HCV) transmission through different modes of sharing injection equipment and sexual behavior among injecting drug users (IDUs) in Liangshan of Sichuan province. METHODS: A community-based survey was conducted to investigate past and current demographic data, injection equipment sharing patterns and sexual behavior of IDUs. Blood samples were also taken to test for HCV. The survey was conducted between Nov 8 and Nov 29, 2002. 379 subjects were screened through outreach recruitment and peer informing. SPSS (11.5) was used for data analysis. RESULTS: HCV prevalence was 71.0% (269/379). Needles or syringes sharing in the past three months and past syphilis infection were strongly associated with HCV transmission after univariate analysis using chi-square test. Trend analysis indicated that HCV infection rate increased along with the increase of needles or syringes sharing, sharing of rinse water and the number of peers sharing the equipments. Data from multivariate logistic regression showed that sharing of needles or syringes and history of syphilis infection were significantly associated with HCV transmission. No significant difference was found between HCV infection and sexual behavior after univariate analysis using chi-square test. CONCLUSION: Further sero-epidemiological prospective cohort studies should be conducted to clarify the relationship between different modes of sharing injection equipment, sexual behavior and HCV infection.

Adult↗

PubMed2004

[A clinical study about occupational noise-induced hearing loss measured and diagnosed with transient evoked otoacoustic emissions].

OBJECTIVE: To study the feasibility and clinical values of occupational noise-induced hearing loss measured, evaluated and diagnosed with transient evoked otoacoustic emissions (TEOAE). METHOD: Pure tone threshold and TEOAE were performed in 11 (22 ears) young adults with normal hearing of control group and 90 (180 ears) noise exposure workers of test group. According to length of noise exposure time, test group was disparted to test 1,2,3 groups. Stimulated tone of TEOAE is non-linearity click of 80 dB SPL. RESULT: In test group and test 1,2,3 group against control, pure tone threshold in all frequency increased significantly, and correlation, strength and SNR of TEOAE in overall and every frequency declined significantly (P<0.05 or P<0.01). To observe test 1,2,3 group, It was found that pure tone threshold in all frequency increased and correlation, strength and SNR of TEOAE in overall and every frequency declined, when length of noise exposure time is increased. In 2.50-3.50 and 3.50-4.50 kHz, measuring values of TEOAE declined most significantly. CONCLUSION: Occupational noise-induced hearing loss can been measured and diagnosed significantly with TEOAE. The best observed contents is correlation, strength and SNR of TEOAE in overall and every part frequency. The best sensitivity observed frequency parts of TEOAE is 2.50-3.50 and 3.50-4.50 kHz.

Adolescent↗

PubMed2004

[Community-based survey on human immunodeficiency virus infection among injection drug users in Sichuan, China].

OBJECTIVE: To investigate prevalence of human immunodeficiency virus (HIV) infection and risk factors for its transmission among injection drug users (IDUs) in Liangshan Yizu Autonomous Prefecture of Sichuan Province, China. METHODS: A community-based survey was conducted to investigate demographic characteristics, pattern and frequency of sharing injection equipment, and sexual behaviors in IDUs. Blood samples were also collected from them to detect for antibodies against HIV and syphilis. RESULTS: A total of 379 subjects were recruited with informed consent for study through community outreach and peer recruiting methods. Their prevalence of HIV infection was 11.3% (43/379). Ethnicity, frequency of sharing syringes and cotton swab during the past three months and syphilis infection associated with HIV infection by univariate analysis using chi-square test. Multivariate logistic regression analysis showed odds ratio of frequency of sharing syringes for HIV infection during the past three months was 2.28 (95% CI 1.18 - 4.43), and that for syphilis infection 3.10 (95% CI 1.48 - 6.48). CONCLUSION: Frequency of sharing syringes during the past three months associated with syphilis and HIV infection.

Adolescent↗

PubMed2004

Induction of T-cell immunity against Epstein-Barr virus-associated tumors by means of adenovirally transduced dendritic cells.

BACKGROUND: Dendritic cells (DCs) are the most powerful antigen-presenting cells to induce specific T-cell immunity, which plays an important role in the body's anti-tumor responses. In this study, we assessed the feasibility and efficacy of inducing T-cell immunity against Epstein-Barr virus (EBV)-associated tumors in vivo using dendritic cells transfected with EBV latent membrane 2A (LMP2A) recombinant adenovirus. METHODS: Cytokine-activated bone marrow-derived DCs transfected with EBV LMP2A recombinant adenovirus were infused into BALB/c mice. Splenic cytotoxic T-cell responses were evaluated by cytotoxicity and interferon-gamma production assays. in vivo immune protection was then assessed in the mice tumor models implanted with tumor cells expressing EBV LMP2A. RESULTS: DCs transfected with EBV LMP2A recombinant adenovirus could strongly induce EBV LMP2A-specific cytotoxic T-cell responses and upregulate interferon-gamma production in vivo. Vaccination using these DCs led to prolongation of overall survival rates in the mice tumor models and retarded tumor growth. CONCLUSIONS: The results suggest that DCs transfected with EBV LMP2A recombinant adenovirus can serve as a feasible and effective tool for eliciting LMP2A-specific cytotoxic T-cell responses against EBV LMP2A in vivo in the treatment of EBV-associated tumors.

Adenoviridae↗

PubMed2004

[IL-8 and TNF-alpha in prostatic secretions as indications in evaluating chronic prostatitis].

OBJECTIVE: To investigate the significance of the determination of IL-8 and TNF-alpha in prostatic secretions in the evaluation of chronic prostatitis. METHODS: IL-8 and TNF-alpha levels in EPS were evaluated by ELISA in 90 men: controls (n = 12), CBP (n = 12), CPPS IIIA (n=38), CPPS IIIB (n=28). And the difference was analyzed between CBP or CPPS IIIA and CPPS IIIB or controls. RESULTS: IL-8 and TNF-alpha levels in EPS were higher in men with CBP [(10967.5 +/- 3477.7) pg/ml, (84.1 +/- 54.7) pg/ml] or CPPS IIIA [(9268.4 +/- 2034.6) pg/ml and (32.6 +/- 18.6) pg/ml], but lower in men with CPPS IIIB [(2726.1 +/- 277.5) pg/ml, (12.6 +/- 7.1) pg/ml] or controls [(2800.0 +/- 320.2) pg/ml and (12.9 +/- 10.1) pg/ml] respectively. There was significant difference between CBP or CPPS IIIA and CPPS IIIB or controls (P < 0.01). CONCLUSION: IL-8 and TNF-alpha are elevated in the EPS of the men with CBP and CPPS IIIA, and provide a novel means for the identification and characterization of chronic nonbacterial prostatitis/chronic pelvic pain syndrome. The cut-points for IL-8 and TNF-alpha to discriminate CBP or CPPS IIIA from CPPS IIIB or controls need further investigation.

Adult↗

PubMed2003

[Changes of STAT3 in cell replicative senescence and effects of angiotensin II on STAT3].

OBJECTIVE: To investigate the changes of STAT3 in cell replicative senescence and the effects of angiotensin II (AngII) on STAT3. METHODS: Normal human fetal lung diploid fibroblast cell line WI-38 was cultured and the senescent cell was defined with beta-gal staining. Electrophoretic mobility shift assay and Western blotting assay were used to detect the activation of STAT3 during cell replicative senescence and examine the process of STAT3 activation with AngII. RESULTS: The synthesis of STAT3 protein during the course of cell replicative senescent increased, the nuclear translocation of phosphorylated STAT3 decreased, and the activities of STAT3 binding DNA reduced. CONCLUSION: AngII induces the activation of STAT3 in both mature and senescence cell by AT(1) receptor, however, the reaction of senescent cell to AngII is weaker. The site of block may be in the nuclear translocation. AngII induces the activity of STAT3 in replicative senescence WI-38.

Active Transport, Cell Nucleus↗

PubMed2003

Human MutS homologue MSH4 physically interacts with von Hippel-Lindau tumor suppressor-binding protein 1.

Increasing evidence indicated that the protein factors involved in DNA mismatch repair (MMR) possess meiotic functions beyond the scope of DNA mismatch correction. The important roles of MMR components in meiotic processes have been highlighted by the recent identification of two additional members of the mammalian MutS homologs, MSH4 and MSH5. Mammalian MSH4 and MSH5 proteins form a heterodimeric complex and play an important role in the meiotic processes. As a step forward to the understanding of the molecular mechanisms underlying the roles of these two mammalian MutS homologues, here we have identified von Hippel-Lindau (VHL) tumor suppressor-binding protein 1 (VBP1) as an interacting protein partner for human MSH4 (hMSH4). In addition, we have characterized a hMSH4 splicing variant (hMSH4sv) encoding a truncated form of hMSH4. The protein encoded by hMSH4sv was unable to interact with hMSH5, but it retained the capacity to interact with VBP1. It is conceivable that hMSH4 and hMSH4sv can carry out different but overlapping functions by differential protein interactions, and, therefore, hMSH4sv might represent a separation-of-function alternative form of the hMSH4 protein. hMSH4 and VBP1 proteins were colocalized in mammalian cells. Three-hybrid analysis suggested that VBP1 could compete with hMSH5 for the binding of hMSH4. Thus, hMSH4 may be involved in diverse cellular processes through interaction with different protein partners, and the levels of VBP1 protein expression in cells could potentially affect the availability of the hMSH4-hMSH5 hetero-complex.

Amino Acid Sequence↗

PubMed2003

Improving the quality of adverse drug reaction reporting by 4th-year medical students.

PURPOSE: Evaluate whether a 15-minute lecture intervention will improve adverse drug reaction reporting quality on standard MedWatch forms. METHODS: Seventy-eight 4th-year medical students were randomized to intervention 'Group-A' or non-intervention 'Group-B' on the first day of a required five-day clinical pharmacology rotation. Group-A participants attended a 15-minute lecture on completing a MedWatch form with quality information considered by the Food and Drug Administration as critical to adequate adverse drug reaction reporting. Group-B participants did not attend this lecture. Both groups then watched a standardized patient interview of a recognizable adverse drug reaction and completed MedWatch forms. Four Safety Evaluators from the Food and Drug Administration (FDA) rated student responses in a blinded fashion for the primary efficacy variable of Overall Impression and six informational domins using a standardized data quality analysis form that was developed within the Office of Postmarketing Drug Risk Assessment of the FDA. RESULTS: Seventy-eight MedWatch forms were evaluated (Group-A = 40, Group B = 38). Overall MedWatch information quality scores for the intervention group were significantly higher than the non-intervention group (p < 0.004). CONCLUSIONS: As little as a 15-minute intervention can significantly improve the quality of adverse drug reaction reporting by 4th-year medical students. Academic medical centers should consider incorporating adverse drug reaction reporting curriculum into the clinical training of medical students.

Adverse Drug Reaction Reporting Systems↗

PubMed2003

Diagnosis and management of severe acute pancreatitis complicated with abdominal compartment syndrome.

Presented in this paper is our experience in the diagnosis and management of abdominal compartment syndrome during severe acute pancreatitis. On the basis of the history of severe acute pancreatitis, after effective fluid resuscitation, if patients developed renal, pulmonary and cardiac insufficiency after abdominal expansion and abdominal wall tension, ACS should be considered. Cystometry could be performed to confirm the diagnosis. Emergency decompressive celiotomy and temporary abdominal closure with a 3 liter sterile plastic bag must be performed. It is also critical to prevent reperfusion syndrome. In 23 cases of ACS, 18 cases received emergency decompressive celiotomy and 5 cases did not. In the former, 3 patients died (16.7%) while in the later, 4 (80%) died. Total mortality rate was 33.3% (7/21). In 7 death cases, 4 patients developed acute obstructive suppurative cholangitis (AOSC). All the patients who received emergency decompressive celiotomy 5 h after confirmation of ACS survived. The definitive abdominal closure took place mostly 3 to 5 days after emergency decompressive celiotomy, with longest time being 8 days. 6 cases of ACS at infection stage were all attributed to infected necrosis in abdominal cavity and retroperitoneum. ACS could occur in SIRS stage and infection stage during SAP, and has different pathophysiological basis. Early diagnosis, emergency decompressive celiotomy and temporary abdominal closure with a 3L sterile plastic bag are the keys to the management of the condition.

Abdomen↗

PubMed2003

STAT proteins mediate angiotensin II-induced production of TIMP-1 in human proximal tubular epithelial cells.

BACKGROUND: Angiotensin II and tissue type inhibitor metalloproteinase-1 (TIMP-1) have been implicated in renal tubulointerstitial fibrosis, but the exact mediating signaling pathway is still unknown. Angiotensin II has been reported to activate signal transducers and activators of transcription (STAT) and induce proliferation of myocyte and vascular smooth muscle cells (VSMC). We hypothesized that the STAT signal pathway is involved in the process of renal tubulointerstitial fibrosis. Therefore, we designed the present study to explore whether angiotensin II could induce TIMP-1 expression in human proximal tubular epithelial cells, and whether it was mediated through the STAT signaling pathway. METHODS: Electrophoretic mobility shift assay (EMSA) was employed to determine the DNA-STAT binding activity. Supershift assay was used to test the components of activated STAT proteins. Nuclear translocation of activated STATs was observed with laser scanning confocal microscopy. TIMP-1 expression was analyzed with Northern and Western blots. Valsartan and PD123319 were used to block the effects of angiotensin II type 1 (AT1) and angiotensin II type 2 (AT2) receptors of angiotensin II, respectively. RESULTS: Cultured human proximal tubular epithelial cells constitutively expressed TIMP-1. Angiotensin II induced TIMP-1, mRNA, and protein expressions in time- and dose-dependent manners, which could be inhibited by the AT1 receptor antagonist valsartan, but not by the AT2 antagonist PD123319. Angiotensin II also activated STAT-DNA binding activity in both dose-dependent and biphasic time-dependent manners, and increased the phosphorylation and nuclear translocation of STAT proteins. To examine the role of STAT in angiotensin II-induced TIMP-1 expression, STAT1 and STAT3 antisense oligonucleotides were used. Northern and Western blots showed that STAT1 and STAT3 antisense oligonucleotides could inhibit angiotensin II-induced TIMP-1 expressions, and STAT1 and STAT3 proteins, respectively, could be supershifted by their polyclonal antibodies. CONCLUSION: STAT1 and STAT3 may, at least in part, mediate angiotensin II-induced TIMP-1 mRNA expression in human renal proximal tubular epithelial cells, implicating a role of the STAT signaling pathway in pathogenesis of renal tubulointerstitial fibrosis.

Angiotensin II↗

PubMed2003

Inhaled fluticasone propionate by diskus in the treatment of asthma: a comparison of the efficacy of the same nominal dose given either once or twice a day.

STUDY OBJECTIVE: In September 2000, the US Food and Drug Administration (FDA) approved the use of Flovent Diskus (FD) [fluticasone propionate; GlaxoSmithKline; Research Triangle Park, NC], which is an orally inhaled, dry-powder corticosteroid, for the maintenance treatment of asthma at dosages of 50 to 1,000 microg administered twice-daily. Once-daily dosage regimens did not receive approval. This article will detail six clinical trials, five of which incorporated comparative once-daily and twice-daily treatment arms of the same nominal dose of FD. DESIGN: Six 12-week, randomized, double-blind, placebo-controlled studies in patients with mild-to-moderate asthma, including two pediatric asthma trials (patient age, 4 to 11 years) of total daily doses of fluticasone propionate (FP) of 100 or 200 microg, and four adult and adolescent studies of total daily doses of FP of 100, 200, or 500 microg. RESULTS: Twice-daily dosing was numerically superior to once-daily dosing at the same nominal dose in all comparative studies for the primary end point, change in predose FEV(1). In five trials, the results of the once-daily dosage of FP were statistically indistinguishable from those with placebo. One trial demonstrated the superiority of FP, 500 microg once-daily, over placebo; however, the effect size was half that observed with twice-daily dosing. Once-daily FP dosing showed no advantage in safety or in patient adherence to medication. CONCLUSIONS: In the FDA review of once-daily dosing of the FD regimen, 100 or 200 microg once-daily dosing was not shown to be significantly better than placebo. FP 500 microg once-daily was found to be superior to placebo, but at about one half the effect size as the same nominal dose given bid. No advantage in patient safety or adherence was demonstrated for once-daily administration over twice-daily administration, and once-daily administration is not currently recommended.

Administration, Inhalation↗

PubMed2003

Generation of cytotoxic T cell against HBcAg using retrovirally transduced dendritic cells.

AIM: Cytotoxic T lymphocytes (CTLs) play an important role in resolving HBV infection. In the present study, we attempted to evaluate the efficiency of bone marrow-derived dendritic cells (DCs) transduced with recombinant retroviral vector bearing hepatitis B virus (HBV) core gene and the capability of generating CTLs against HBcAg by genetically modified DCs in vivo. METHODS: A retroviral vector containing HBV core gene was constructed. Replicating DC progenitor of C57BL/6 mice was transduced by retroviral vector and continually cultured in the presence of recombinant mouse granulocyte-macrophage colony-stimulating factor (rmGM-CSF) and interleukin-4(IL-4) for 6 days. LPS was added and cultured for additional two days. The efficiency of gene transfer was determined by PCR, Western blot and FACS. Transduced DCs immunized C57BL/6 mice subcutaneously 2 times at an one-week interval. Intracellular IFN-gamma and IL-4 of immunized mice lymphocytes were analyzed. Generation of CTLs in lymphocytes stimulated with mitomycin C-treated EL4-C cell which stably expresses HBcAg was determined by LDH release assays. RESULTS: Recombinant retroviral expression vector (pLCSN) was positively detected by PCR as well as enzyme digestion with EcoRI and BamH I. Retroviruses were generated by pLCSN transfection packing cell and the virus titer was 3 x 10(5) CFU/ml. Indirect immunofluorescence and FACS showed that HBV core gene was expressed in murine fibroblasts. Transduced bone marrow cells had capability of differentiating into DCs in vitro in the presence of rmGM-CSF and rmIL-4. The result of PCR showed that HBV core gene was integrated into the genome of transduced DCs. Western blot analysis showed that HBV core gene was expressed in DCs. The transduction rate was 28 % determined by FACS. Retroviral transduction had no influence on DCs expressions of CD80 and MHC class II. HBcAg specific CTLs and Th1 type immune responses could be generated in the mice by using transduced DCs as antigen presenting cells (APCs). CONCLUSION: Retroviral transduction of myeloid DCs progenitors expresses efficiently HBcAg, and genetically modified DCs evoke a higher CTLs response than HBcAg in vivo.

Animals↗

PubMed2002

High accuracy mass measurement of peptides with internal calibration using a dual electrospray ionization sprayer system for protein identification.

A dual-ESI-sprayer system was constructed and applied to achieve high accuracy of peptide mass measurement for protein identification by means of peptide mapping. Sample was introduced in one sprayer, and reference in the other, thus making internal calibration possible greatly enhancing the mass accuracy. Several samples were utilized to evaluate the reliability of this dual-ESI-sprayer system. The range of mass errors was 0.16-5.37 ppm. The peptide masses of tryptic digests of myoglobin (horse) were measured by the HPLC/dual-ESI-MS system, with mass deviations ranging from 0.01-7.67 ppm, and about 75% mass deviations below 5 ppm with 40% below 1[?]ppm. These peptide masses were utilized to perform database searching for protein identification, and compared to results obtained by external calibration. This comparison showed that the internal calibration provides a more reliable method of protein identification, with a much smaller number of required peptides for matching, and with less CPU time consumed for database searching.

Animals↗

PubMed2002

Quantitative determination of Freon gas using an electronic nose.

This paper reports a quantitative electronic nose (enose) for the quantitative determination of Freon gas within the concentration range 0-1000 ppm in the presence of interfering gases such as water, lubricant and petrol vapours. This quantitative enose is a new type of Freon detection system, composed of an array of four sensors. The artificial neural network (ANN) and fuzzy logic type of ANN (FNN), in combination with the relative error concept in analytical chemistry, are integrated for both quantification and discrimination. The predicted results are satisfied with a pass rate of > 80% within the permitted relative errors. The results show that the Freon enose developed in this study is reliable for both the qualitative and quantitative determination of Freon gas and exhibits the merits of high sensitivity, anti-interference and accuracy.

Air Conditioning↗

PubMed2002

[Comparison of perioperative myocardial injury between off-pump coronary artery bypass grafting and conventional coronary artery bypass grafting].

OBJECTIVE: To compare the perioperative release levels of cardiac troponin I (cTnI) between off-pump coronary artery bypass grafting (OPCAB) or conventional coronary artery bypass grafting (CCABG) in an attempt to detect myocardial injury. METHODS: Fifty-nine patients with instable angina underwent coronary artery bypass grafting by OPCAB in 34 patients aged (59.15 +/- 1.71) years or CCABG in 25 patients, aged (54.46 +/- 1.81) years. RESULTS: Baseline characteristics were similar. The number of grafts was similar (OPCAB, mean 2.90; CCABG, mean 3.2), and no patient died. Postoperative myocardial serum enzyme measures were significantly lower in OPCAB, suggesting less myocardial injury. OPCAB patients did not receive blood transfusion, and had higher hematocrit at discharge. Most of OPCAB patients were extubated in 4 hours. CONCLUSIONS: Compared with CCABG, OPCAB may achieve similar outcomes; it reduces transfusion volume and creates less myocardial injury.

Cardiomyopathies↗

PubMed2002

[Modulation of lianbizi injection (andrographolide) on some immune functions].

OBJECTIVE: To study the effects of andrographolide on immune functions and the immune mechanism of its clinical application. METHOD: The amounts of IFN-alpha, IFN-gamma, TNF-alpha, IL-8 in the peripheral blood mononuclear cells(PBMCs) culture supernatants deal with by different concentrations of LianBiZhi (LBZ) injection made of andrographolide were detected by biological activity test or ELISA in vitro. The effects of LBZ injection on macrophage phagocytotic function and natural killer cells cytotoxicity were examined by means of macrophage to phagocytize cock erythrocyte and measurement of lactate dehydrogenase(LDH) activity released from the damaged cells, respectively. RESULT: The LBZ injection could promote IFN-alpha, IFN-gamma, TNF-alpha inductions of PBMCs, but had no effect on IL-8. At the same time, the LBZ injection could not only enhance the phagocytosis activity of peritoneal macrophage from guinea pig to phagocytosis cock erythrocyte, but also augment the cytotoxicity mediated by natural killer cells from PBMCs to damage the K562 cell lines. CONCLUSION: Andrographolide is an immunostimulant agent which can modulate both antigen specific and nonspecific immune function by means of its natural killer cells and macrophage and cytokines induction.

Animals↗

PubMed2002

[Preparation of polymer modified stationary phases through surface radical chain transfer reaction].

It is demonstrated that radical chain transfer to thiol-terminated self-assembled monolayer and surface-initiated polymerization could be used for in-situ grafting ultra-thin polymer film on silica. The widely used silane coupling agent mercaptopropyltrimethoxysilane (MPS) was used to prepare the thiol-terminated silica, and in the presence of which, chain-transfer reaction and polymerization of methyl methacrylate (MMA) was carried out using azo di-isobutylnitrile (AIBN) as the initiator. Both thiol-terminated silica and polymer film modified silica were characterized by Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, thermogravimetric analysis (TGA) and elemental analysis. The results showed that the grafting amount of polymer on silica was higher than the traditional methods, which can effectively relieve the non-specific adsorption of solute with uncovered hydroxyl groups on the surfaces of silica in subsequent chromatographic application. The obtained polymethylmethacrylate (PMMA) modified silica exhibited excellent separation capacity on the separation of the polar compounds and polycyclic aromatic hydrocarbons. This kind of surface initiated polymerization prospects for the preparation of polymer modified stationary phases.

English Abstract↗

PubMed1998

Debrominations of vic-Dibromides with Diorganotellurides. 1. Stereoselectivity, Relative Rates, and Mechanistic Implications.

Debrominations of vic-dibromides with diaryl tellurides 1-4 and di-n-hexyl telluride (9) are described. A mechanistic explanation of the debromination is offered which accounts for several key experimental observations: (1) the reaction is highly stereoselective with erythro-dibromides giving trans-olefins and threo-dibromides giving cis-olefins, (2) the reaction is accelerated by more electron-rich diorganotellurides, (3) the reaction is accelerated in a more polar solvent, (4) the reaction is accelerated by the addition of carbocation-stabilizing substituents to the carbons bearing the bromo substituents, and (5) erythro-dibromides are much more reactive than threo-dibromides. It is proposed that bromonium ion formation from the vic-dibromide is slow and rate-determining. Bromonium ion formation is followed by rapid scavenging of "Br(+)" by the diorganotelluride. The bromonium ion formation provides stereoselectivity and eclipsing interactions lower the reactivity of threo-dibromides. No intermediate species were observed by (1)H NMR.

Journal Article↗