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1.
J Cardiovasc Nurs ; 2024 May 20.
Article in English | MEDLINE | ID: mdl-38768064

ABSTRACT

BACKGROUND: Hypertension is a global health concern that is best managed at the primary care level. In low- and middle-income countries (LMICs) facing resource constraints, collaboration between well-prepared entry-level advanced practice nurses (APNs) and physicians (medical doctors [MDs]) can enhance the care of patients with primary hypertension. OBJECTIVE: The purpose of this study was to evaluate the effectiveness of collaborative entry-level APNs in primary hypertension management, including patient knowledge, physiological and behavioral outcomes, consultation length, and patient satisfaction. METHODS: Sixty-three eligible patients were randomly assigned to either an entry-level APN intervention group or a control group with MDs. Three master's-prepared nurses, trained in hypertension management, acted as entry-level APNs, following the Joint National Committee guidelines in collaboration with a physician. The control group underwent standard clinic consultations. After 1 month, a mixed analysis of variance was used to assess intervention effectiveness, examining both between-groups and within-groups outcomes. RESULTS: Both groups shared similar sociodemographic and baseline characteristics. Significant improvements in blood pressure, body mass index, knowledge, self-management, and medication adherence were found at the 1-month follow-up, with no significant differences in outcomes or patient satisfaction between the entry-level APN and MD groups. However, clinical consultation time was significantly longer for entry-level APNs than for MDs. CONCLUSIONS: Collaborative entry-level APNs managing primary hypertension are comparable with MD care; however, larger, longer trials are essential for a thorough assessment. Strengthening the development of entry-level advanced practice nursing roles in low- and middle-income countries is crucial for addressing service gaps in primary hypertension and other chronic diseases.

2.
Worldviews Evid Based Nurs ; 20(2): 153-161, 2023 Apr.
Article in English | MEDLINE | ID: mdl-36604994

ABSTRACT

BACKGROUND: Nursing students experience higher stress and burnout compared to students in other health professions, with a prevalence rate of as high as 20%. More recently, they have been affected by changes in nursing education due to the COVID-19 pandemic, such as requirements for social isolation and distance learning. Although there are existing studies on interventions that address academic burnout among nursing students, there is no synthesis of randomized trials on this topic. AIM: This study aimed to systematically synthesize studies of interventions for academic burnout among nursing students. METHODS: A systematic search for randomized controlled trials was performed in PubMed, CINAHL, CENTRAL, Web of Science, and Scopus. Eligibility criteria were based on study directness in relation to the Patient, Intervention, Comparison, and Outcome (PICO) question. Two review authors independently screened articles for inclusion, collected data from the included studies, and performed risk of bias assessments using the Cochrane Risk of Bias Tool 2.0. A narrative synthesis was performed. This review was registered a priori in PROSPERO (CRD42022350196). RESULTS: Six papers were included in this review. Various interventions were studied: Qigong exercises, progressive muscle relaxation, autogenic therapy and laughter therapy, didactic behavioral sessions focusing on personal and professional development, and coping skills enhancement. The effects of these interventions on academic burnout, depression, and stress among nursing students were short term and their benefits over time remain uncertain. LINKING EVIDENCE TO ACTION: Progressive muscle relaxation and cognitive behavioral interventions demonstrated short-term positive effects on academic burnout, depression, and stress among nursing students. These findings may support the development of individual-level and organizational-level initiatives for nursing students aimed to lessen or prevent academic burnout. Large-scale, high-quality studies on the effect of interventions on academic burden in various settings and cultures are needed.


Subject(s)
Burnout, Professional , COVID-19 , Students, Nursing , Humans , Pandemics , Burnout, Professional/therapy , Adaptation, Psychological
3.
J Eur Acad Dermatol Venereol ; 34(6): 1263-1272, 2020 Jun.
Article in English | MEDLINE | ID: mdl-31721316

ABSTRACT

BACKGROUND: The Atopic Dermatitis (AD) TREATgermany registry was initiated by the German Society for Dermatology (DDG) in 2011 to evaluate the 'real-life' situation of health care for patients with AD. OBJECTIVES: Interim data analysis on baseline characteristics as well as current and prescribed systemic treatments of the TREATgermany registry patients. METHODS: Patients (≥18 years) with moderate-to-severe AD [objective (o)SCORAD > 20], or with current or previous anti-inflammatory systemic treatment for AD within 24 months, were included and are followed up over at least 24 months. To assess clinical signs, the eczema area severity index (EASI, 0-72), the oSCORAD (0-83) and the Investigator Global Assessment (IGA; 6-point scale) were used. The disease severity was globally scored by the patients [Patient Global Assessment (PGA); six-step Likert scale]. Disease symptoms were assessed by the patient-oriented eczema measure (POEM, 0-28) and numeric rating scales (NRS, 0-10). Health-related quality of life was measured using the dermatological life quality index (DLQI, 0-30). RESULTS: A total of 612 patients were recruited across 32 sites between 06/2016 and 01/2019 (mean age: 42.6 ± 14.2 years; mean oSCORAD: 40.8 ± 16.3). The mean POEM score was 16.3 ± 7.5. Pruritus was rated highest among subjective symptoms (NRS: 5.4 ± 2.7). The mean DLQI value was 11.3 ± 7.5. The frequency of arterial hypertension was lower (20.8%) compared with the general population, whilst this was higher for depression (10%). More than 60% of the patients had received systemic glucocorticosteroids, and 36.8% had received cyclosporine A prior to inclusion. Dupilumab was the leading substance documented as either 'current' (12.1%) or 'prescribed' (31.4%) at baseline. CONCLUSIONS: These 'real-life' data clearly demonstrate the substantial disease burden. Most of TREATgermany patients were already treated with or prescribed dupilumab at baseline. Moreover, current findings indicate the urgent need for further alternative agents in order to achieve a perceptible improvement of quality of life of patients with moderate-to-severe AD.


Subject(s)
Dermatitis, Atopic , Eczema , Adult , Dermatitis, Atopic/drug therapy , Humans , Middle Aged , Quality of Life , Registries , Severity of Illness Index
4.
Article in English | WPRIM (Western Pacific) | ID: wpr-960816

ABSTRACT

Background@#The COVID-19 pandemic has put an immense strain on health systems worldwide. Nurses at the front line are prone to experience several staffing issues facing ever-increasing stresses to the health care system by a pandemic situation. The staffing experiences of nurses in this context can have a significant impact on current nursing practice and existing policies.@*Objective@#To carry out a synthesis of the scientific evidence available on the staffing experiences of nurses during the SARS, MERS, and Ebola epidemics.@*Method@# A narrative review was conducted. A literature search was carried out in PubMed, Scopus, and CINAHL databases. All studies describing nurses' experiences were included regardless of methodology. Atotal of 16 articles was included in the review.@*Results@#Narrative synthesis revealed ten themes from the results of the articles: training, staffing ratios and models, shifting models, volunteer staffing, skill mix, planning staffing needs, hospital preparedness, communication, effects of workload, and structured workflow processes.@*Conclusions@#Nurses are pivotal to the healthcare response to infectious disease pandemics and epidemics. The results of this review should provide a basis for nurse managers and administrators on how they can actively engage in supporting the staffing concerns and issues of nurses during the COVID-19 pandemic.


Subject(s)
COVID-19 , Pandemics
5.
J Eur Acad Dermatol Venereol ; 33(1): 147-150, 2019 Jan.
Article in English | MEDLINE | ID: mdl-29953684

ABSTRACT

BACKGROUND: Dry skin is a frequent and multifaceted condition which can be associated with skin irritation, itch, patient discomfort and manifest skin disease. In spite of being frequent, little is known about the epidemiology of dry skin in the population. OBJECTIVE: To determine the prevalence of dry skin in the German adult population. METHODS: Data of 48 630 employed persons were assessed on a cross-sectional level in whole-body examinations by experienced dermatologists during company-based skin screenings conducted in 343 German companies. Next to the current dermatologic findings, age, gender, allergies, atopic diseases and the skin type were assessed. RESULTS: In total, n = 14 300 persons (29.4%) were rated as having xerotic skin. Older age but not gender was associated with xerosis. In the regression analyses controlling for age and gender, dry skin was a significant predictor for: axillary dermatitis (OR: 4.51; CI 2.70-7.54), atopic eczema (OR: 3.99; CI 3.42-4.65), exsiccation eczema (OR: 2.96; CI 2.40-3.65), psoriasis (OR: 1.57; CI 1.38-1.78), plantar warts (OR: 1.42; CI 1.26-1.60), seborrhoeic dermatitis (OR: 1.28; CI 1.16-1.42) and atopic disposition (OR: 1.17; CI 1.12-1.22). CONCLUSION: Dry skin is a frequent condition in the adult general population and needs special attention. Known risk factors may facilitate identifying patients at risk for deterioration.


Subject(s)
Skin Diseases/epidemiology , Adult , Age Factors , Cross-Sectional Studies , Dermatitis, Atopic/epidemiology , Dermatitis, Seborrheic/epidemiology , Female , Germany/epidemiology , Humans , Hypersensitivity/epidemiology , Male , Middle Aged , Prevalence , Psoriasis/epidemiology , Warts/epidemiology
6.
Hautarzt ; 69(10): 815-824, 2018 Oct.
Article in German | MEDLINE | ID: mdl-30191254

ABSTRACT

BACKGROUND: Clinical registries may provide high-quality evidence on the use and effectiveness of therapeutic interventions under real-life conditions. Adults with moderate-to-severe atopic eczema (atopic dermatitis [AD]) are enrolled into TREATgermany and prospectively followed over at least 2 years. This paper analyses the association between dermatological quality of life and work limitations. MATERIALS AND METHODS: Treatment modalities and a broad set of physician- and patient-reported outcome measures are documented using validated instruments to assess clinical disease severity (EASI [Eczema Area and Severity Index], objective SCORAD [objective-SCORing Atopic Dermatitis]), quality of life (DLQI [Dermatology Life Quality Index]), symptoms (POEM [Patient-oriented Eczema Measure]), global disease severity, as well as patient satisfaction and work limitations including presenteeism (WLQ [Work Limitation Questionnaire]). From 06/2016 until 12/2017, 241 individuals (mean age 43 ± 15 years, 38.6% female) were enrolled at 19 recruitment centers; 69% of the patients were employed. RESULTS: Employed persons had DLQI and WLQ scores of 10.6 ± 6.9 points and 17.7 ± 18.1%, respectively. Mean presenteeism was substantial accounting for 9.2%. With coefficients of 0.39 and 0.33 WLQ and presenteeism scores significantly correlate with DLQI (p < 0.000). Bootstrapped regression models showed that the limitations in coping with work requirements increase by 1.7% as DLQI increases by one point. Lower quality of life due to AD is most strongly associated with limitations in the area of physical and performance requirements in general. Presenteeism increases by 0.5% as DLQI increases by one point. CONCLUSION: Moderate-to-severe AD has substantial adverse economic impact with mean productivity loss of patients of almost 10%. Future analyses from TREATgermany will address the impact of innovative treatment modalities on quality of life and work productivity of patients with moderate-to-severe AD.


Subject(s)
Clinical Competence , Dermatitis, Atopic , Eczema , Registries , Adult , Dermatitis, Atopic/therapy , Female , Humans , Male , Middle Aged , Quality of Life , Severity of Illness Index
8.
Allergy ; 73(2): 442-450, 2018 02.
Article in English | MEDLINE | ID: mdl-28795768

ABSTRACT

BACKGROUND: Hereditary angioedema (HAE) with normal C1-INH (HAEnCI) may be linked to specific mutations in the coagulation factor 12 (FXII) gene (HAE-FXII) or functional mutations in other genes that are still unknown. We sought to identify and characterize a hitherto unknown type of HAE with normal C1-INH and without mutation in the F12 gene. METHODS: The study comprised analysis of whole-exome sequencing, Sanger sequencing, and clinical data of patients. RESULTS: We detected a mutation in the plasminogen (PLG) gene in patients with HAEnCI. The mutation c.988A>G was located in exon 9 leading to the missense mutation p.Lys330Glu (K330E) in the kringle 3 domain of the PLG protein. The mutation was identified by next-generation sequencing in 14 patients with HAEnCI belonging to 4 of 7 families. Family studies revealed that this type of HAE was transmitted as an autosomal dominant trait. The PLG gene mutation was present in all studied symptomatic patients and was also found in 9 of 38 index patients from 38 further families with HAEnCI. Most patients had swelling of face/lips (78.3%) and tongue (78.3%). A total of 331 of all 3.795 tongue swellings (8.7%) were associated with dyspnea, voice changes, and imminent asphyxiation. Two women died by asphyxiation due to a tongue swelling. CONCLUSIONS: Hereditary angioedema with a mutation in the PLG gene is a novel type of HAE. It is associated with a high risk of tongue swellings.


Subject(s)
Angioedemas, Hereditary/genetics , Mutation/genetics , Plasminogen/genetics , Adolescent , Adult , Aged , Child , Child, Preschool , Female , Germany , Humans , Male , Middle Aged , Mutation, Missense/genetics , Exome Sequencing/methods , Young Adult
9.
Oncol Nurs Forum ; 43(2): 136-40, 2016 Mar.
Article in English | MEDLINE | ID: mdl-26906124

ABSTRACT

Cushing's syndrome is a state of cortisol excess, possibly from a tumor in the pituitary gland, the adrenal gland, or an ectopic nonpituitary ACTH-secreting source. The first form, pituitary in origin, was originally described by Harvey Cushing, MD, and was labeled as Cushing's disease. Long-term therapy with glucocorticoids also can lead to iatrogenic Cushing's syndrome.


Subject(s)
ACTH Syndrome, Ectopic/diagnosis , Adenoma/physiopathology , Cushing Syndrome/diagnosis , Cushing Syndrome/etiology , Cushing Syndrome/therapy , Glucocorticoids/adverse effects , Pituitary Gland/physiopathology , Adolescent , Humans , Male , Philippines , Treatment Outcome
11.
Knee Surg Sports Traumatol Arthrosc ; 22(8): 1926-31, 2014 Aug.
Article in English | MEDLINE | ID: mdl-24832693

ABSTRACT

PURPOSE: The objective of the study was to clarify whether driving abstinence should be recommended when patients are discharged from hospital after unicompartmental knee arthroplasty (UKA). We tested the hypotheses that there are differences in the peri-operative course of brake response time in patients undergoing right-sided (1) or left-sided (2) UKA. Additionally, we tested whether brake response time is significantly influenced by pain (3), driving experience (4) or age (5). METHODS: In 43 patients undergoing UKA, brake response time was measured with a custom-made driving simulator pre-operatively and 1 and 6 weeks after UKA. Patients' visual analogue scales for knee pain and their self-reported driving experience were also assessed. RESULTS: In patients with right-sided UKA, brake response time changed from 786 (261) ms pre-operatively to 900 (430) ms 1 week post-operatively (p = 0.029). At 6 weeks post-operatively, brake response time had returned to 712 (139) ms, which was deemed to be an insignificant change from the pre-operative reference benchmark. When surgery was performed on the contralateral left side, no effect was found onto the right side's brake response time. Knee pain and driving experience were significantly correlated with brake response time. No such correlations were found between brake response time and age. CONCLUSIONS: On the basis of the current findings, it is concluded that brake response time returns to pre-operative levels 6 weeks after UKA surgery. Therefore, it is proposed that driving be abstained from for that period.


Subject(s)
Arthroplasty, Replacement, Knee , Automobile Driving , Osteoarthritis, Knee/physiopathology , Osteoarthritis, Knee/surgery , Reaction Time , Aged , Arthralgia/diagnosis , Arthralgia/physiopathology , Female , Humans , Knee Joint/physiopathology , Knee Joint/surgery , Male , Middle Aged , Patient Education as Topic , Postoperative Period , Recovery of Function
12.
Eur J Pediatr ; 171(9): 1339-48, 2012 Sep.
Article in English | MEDLINE | ID: mdl-22543566

ABSTRACT

Hereditary angioedema due to C1 inhibitor (C1 esterase inhibitor) deficiency (types I and II HAE-C1-INH) is a rare disease that usually presents during childhood or adolescence with intermittent episodes of potentially life-threatening angioedema. Diagnosis as early as possible is important to avoid ineffective therapies and to properly treat swelling attacks. At a consensus meeting in June 2011, pediatricians and dermatologists from Germany, Austria, and Switzerland reviewed the currently available literature, including published international consensus recommendations for HAE therapy across all age groups. Published recommendations cannot be unconditionally adopted for pediatric patients in German-speaking countries given the current approval status of HAE drugs. This article provides an overview and discusses drugs available for HAE therapy, their approval status, and study results obtained in adult and pediatric patients. Recommendations for developing appropriate treatment strategies in the management of HAE in pediatric patients in German-speaking countries are provided.Conclusion Currently, plasma-derived C1 inhibitor concentrate is considered the best available option for the treatment of acute HAE-C1-INH attacks in pediatric patients in German-speaking countries, as well as for short-term and long-term prophylaxis.


Subject(s)
Complement C1 Inhibitor Protein/therapeutic use , Complement Inactivating Agents/therapeutic use , Hereditary Angioedema Types I and II/drug therapy , Adolescent , Adult , Androgens/therapeutic use , Anti-Inflammatory Agents, Non-Steroidal/therapeutic use , Antifibrinolytic Agents/therapeutic use , Austria , Bradykinin/analogs & derivatives , Bradykinin/therapeutic use , Child , Complement C1 Inactivator Proteins/therapeutic use , Disease Progression , Germany , Humans , Peptides/therapeutic use , Recombinant Proteins/therapeutic use , Switzerland
13.
Diabet Med ; 28(1): 31-5, 2011 Jan.
Article in English | MEDLINE | ID: mdl-21210540

ABSTRACT

AIM: To analyse the performance of HbA(1c) in diagnosing Type 2 diabetes based on fasting plasma glucose and/or 2-h plasma glucose measurements after a 75-g oral glucose tolerance test. METHODS: This is a study of diagnostic test accuracy in individuals referred to the Clinical Pathology Department for oral glucose tolerance testing. After fasting overnight, HbA(1c), fasting plasma glucose and 2-h plasma glucose were measured. The receiver operating characteristic curve was used to evaluate the diagnostic performance of HbA(1c). RESULTS: Four hundred and ninety-eight subjects (195 male, mean age 56 years) were enrolled and 115 (23.1%) were diagnosed with diabetes according to glucose-based methods and only 56 (11.2%) individuals were identified by HbA(1c) ≥ 6.5% (48 mmol/mol) (sensitivity 20.9%, specificity 95.3%). There is poor agreement between the newly recommended criterion and the current glucose-based diagnostic criteria (κ = 0.217; P < 0.001), probably because the diagnostic methods identify different populations of patients. Adding a glucose-based method into an algorithm, as proposed by the UK Department of Health, improved HbA(1c) performance. CONCLUSIONS: HbA(1c) ≥ 6.5% (48 mmol/mol) showed limited sensitivity to diabetes diagnosis, although with high specificity. The results suggest that this cut-off point would not be enough to diagnose diabetes. Its use as the sole diabetes diagnostic test should be interpreted with caution to assure the correct classification of diabetic individuals.


Subject(s)
Blood Glucose/metabolism , Diabetes Mellitus, Type 2/diagnosis , Glucose Tolerance Test/methods , Glycated Hemoglobin/metabolism , Diabetes Mellitus, Type 2/epidemiology , Diabetes Mellitus, Type 2/metabolism , Fasting , Female , Humans , Male , Middle Aged , Reference Standards , Sensitivity and Specificity , United Kingdom/epidemiology
14.
Hautarzt ; 58(8): 693-7, 2007 Aug.
Article in German | MEDLINE | ID: mdl-17453168
15.
Arch Microbiol ; 173(1): 76-7, 2000 Jan.
Article in English | MEDLINE | ID: mdl-10648108

ABSTRACT

Under microaerophilic conditions Salmonella typhimurium LT2 synthesizes cobalamin, during which 5,6-dimethylbenzimidazole is formed from riboflavin. We report here that in an anoxic environment S. typhimurium did not form cobalamin, but rather adenylcobamide, 2-methyladenylcobamide, and cobyric acid. This indicated that S. typhimurium, like other microorganisms that synthesize 5,6-dimethylbenzimidazole from riboflavin, requires oxygen for the formation of the cobalamin base.


Subject(s)
Cobamides/metabolism , Salmonella typhimurium/metabolism , Vitamin B 12/metabolism , Anaerobiosis , Riboflavin/metabolism , Salmonella typhimurium/growth & development
16.
Arch Microbiol ; 171(1): 66-8, 1998 Dec.
Article in English | MEDLINE | ID: mdl-9871021

ABSTRACT

In order to elucidate the biosynthesis of the base moiety of cobalamin in Salmonella typhimurium LT2, this organism was grown in the presence of [1'-14C]riboflavin. The vitamin B12 isolated was 14C-labeled. It was shown by chemical degradation that the 14C-label was exclusively localized in carbon atom 2 of the 5,6-dimethylbenzimidazole moiety. This demonstrated the precursor function of riboflavin in the biosynthesis of 5,6-dimethylbenzimidazole in S. typhimurium.


Subject(s)
Benzimidazoles/metabolism , Riboflavin/metabolism , Salmonella typhimurium/metabolism , Vitamin B 12/biosynthesis
17.
Eur J Biochem ; 254(3): 620-5, 1998 Jun 15.
Article in English | MEDLINE | ID: mdl-9688274

ABSTRACT

In anaerobic bacteria 5-hydroxybenzimidazole and 5-hydroxy-6-methylbenzimidazole are precursors of the 5,6-dimethylbenzimidazole moiety of vitamin B12. In order to elucidate the pathway from these bases to vitamin B12, experiments on the transformation of 5-hydroxy-6-methylbenzimidazole, of 5-hydroxy-6-methylbenzimidazole-alpha-D-ribofuranoside, of 5-hydroxybenzimidazolylcobamide and of 5-hydroxy-6-methylbenzimidazolylcobamide into vitamin B12 were carried out. The vitamin B12 synthesized by the anaerobe Eubacterium limosum in the presence of 5-hydroxy-6-methylbenzimidazole and L-[methyl-13C]methionine was subjected to NMR spectroscopy. It revealed that the methyl group at C5 of the 5,6-dimethylbenzimidazole moiety was 13C labeled, whereas the methyl group at C6 was unlabeled. This shows that the transformation of 5-hydroxy-6-methylbenzimidazole into the base moiety of vitamin B12 occurs regiospecifically. 5-Hydroxy-6-methylbenzimidazole-alpha-D-ribofuranoside as well as 5-hydroxybenzimidazolylcobamide and 5-hydroxy-6-methylbenzimidazolylcobamide were also transformed into vitamin B12 by E. limosum. When 5-hydroxy-6-methylbenzimidazolylcobamide 13C labeled at C2 of the base part and 14C labeled in the ribose was used for this experiment, the vitamin B12 obtained from this cobamide was 13C and 14C labeled in the same positions. This demonstrates that the alpha-glycosidic bond of the precursor cobamide is not split during the formation of vitamin B12. It can be deduced from these results that the precursor bases are transformed regiospecifically into their alpha-nucleotides, and partially into their cobamides. The alpha-nucleotides are then transformed into alpha-ribazole-5'-phosphate and, subsequently, into vitamin B12. Most likely the cobamides are degraded to the alpha-nucleotides before being used for the biosynthesis of vitamin B12. A pathway for the latter process is suggested.


Subject(s)
Benzimidazoles/pharmacokinetics , Cobamides/pharmacokinetics , Eubacterium/metabolism , Vitamin B 12/biosynthesis , Benzimidazoles/chemistry , Biotransformation , Carbon Isotopes , Cobamides/chemistry , Magnetic Resonance Spectroscopy , Molecular Structure
18.
Z Naturforsch C J Biosci ; 52(5-6): 287-91, 1997.
Article in English | MEDLINE | ID: mdl-9232888

ABSTRACT

We report on the preparation of 4-aza-5,6-dimethylbenzimidazolylcobamide and 5,6-dimethyl-7-azabenzimidazolylcobamide. These vitamin B12-analogs were required as reference compounds for comparison with a corrinoid previously isolated in small amounts for Eubacterium limosum grown in the presence of 4(5)-aminoimidazole. 4(7)-Aza-5,6-dimethylbenzimidazole was synthesized from N-1-benzyl-4-nitroimidazole which was reduced to N-1-benzyl-4-aminoimidazole and condensed with 1-dimethylamino-2-methylbutan-3-one to yield N-1-benzyl-4-aza-5,6-dimethylbenzimidazole. The benzyl group of this compound was split off by catalytic hydrogenation to form 4(7)-aza-5,6-dimethylbenzimidazole. 4(7)-Aza-5,6-dimethylbenzimidazole was transformed by a growing culture of Propionibacterium shermanii into 4-aza-5,6-dimethylbenzimidazolylcobamide and 5,6-dimethyl-7-azabenzimidazolylcobamide. Both vitamin B12-analogs were almost as active as Vitamin B12 in a growth test with the vitamin B12-dependent Escherichia coli-mutant DSM 4261.


Subject(s)
Cobamides/chemical synthesis , Escherichia coli/drug effects , Vitamin B 12/analogs & derivatives , Vitamin B 12/chemical synthesis , Cobamides/chemistry , Cobamides/pharmacology , Escherichia coli/genetics , Escherichia coli/growth & development , Eubacterium/metabolism , Indicators and Reagents , Magnetic Resonance Spectroscopy , Mass Spectrometry , Molecular Structure , Vitamin B 12/pharmacology
19.
Biol Chem Hoppe Seyler ; 376(10): 595-601, 1995 Oct.
Article in English | MEDLINE | ID: mdl-8590628

ABSTRACT

In anaerobic bacteria, glycine, formate, and the amide-N of glutamine are building blocks for the biosynthesis of the imidazole moiety of the vitamin B12-base 5,6-dimethylbenzimidazole. These building blocks are also used for the biosynthesis of the imidazole moiety of purine bases. Therefore we tested 4(5)-aminoimidazole, the base moiety of the purine nucleotide precursor 5-aminoimidazole ribonucleotide, for its putative function as precursor of 5,6-dimethylbenzimidazole. The anaerobic vitamin B12-producer Eubacterium limosum, grown in the presence of [2-13C]4(5)-aminoimidazole, synthesized nonlabeled vitamin B12, but also [2-13C]7-azabenzimidazolylcobamide and [2-13C]5,6-dimethyl-7-azabenzimidazolylcobamide. [2-13C]limidazole was used by E. limosum to form [2-13C]imidazolylcobamide. Simultaneously nonlabeled vitamin B12 was synthesized. This shows that 4(5)-aminoimidazole and imidazole are not intermediates in the biosynthesis of 5,6-dimethylbenzimidazole. However, 4(5)-aminoimidazole has obviously a structure similar to the structure of an as yet unknown precursor of the vitamin B12-base, and is therefore transformed into the aza analogs. In order to prepare a reference compound 4(5)-azabenzimidazole was added to a culture of Propionibacterium shermanii and to a culture of E. limosum, P. shermanil transformed this base mainly to 4-azabenzimidazolylcobamide, as determined by 1H NMR-spectroscopy (NOE experiment). In contrast E. limosum produced mainly 7-azabenzimidazolylcobamide. The reason for this difference is discussed.


Subject(s)
Cobamides/biosynthesis , Eubacterium/metabolism , Imidazoles/metabolism , Anaerobiosis , Chromatography, Paper , Cobamides/chemistry , Eubacterium/growth & development , Magnetic Resonance Spectroscopy , Mass Spectrometry , Molecular Weight , Purine Nucleotides/metabolism , Spectrophotometry, Ultraviolet , Subcellular Fractions/metabolism
20.
Biol Chem Hoppe Seyler ; 375(11): 785-8, 1994 Nov.
Article in English | MEDLINE | ID: mdl-7695841

ABSTRACT

The transformation of [1-15N]5-hydroxybenzimidazole and [1-15N]5-hydroxy-6-methylbenzimidazole into the 5,6-dimethylbenzimidazole moiety of vitamin B12 by Eubacterium limosum-cultures was studied. The vitamin B12 obtained was exclusively 15N-labeled in N-1 of the base part, as revealed by NMR-measurements. This indicates that either the unsubstituted 5,6-dimethylbenzimidazole presumably formed is not released from the enzyme until the ribose-5'-phosphate substituent is introduced, or that the precursors are first transformed into their alpha-nucleotide-5'-phosphates which then react to form 5,6-dimethylbenzimidazole-alpha-D-ribofuranoside- 5'-phosphate (alpha-ribazole-5'-phosphate).


Subject(s)
Benzimidazoles/metabolism , Eubacterium/metabolism , Vitamin B 12/biosynthesis , Cobamides/biosynthesis , Cobamides/chemistry , Magnetic Resonance Spectroscopy
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