Nuclear magnetic resonance 15N and 1H resonance assignments and global fold of rusticyanin. Insights into the ligation and acid stability of the blue copper site.

Nuclear magnetic resonance assignments are reported at pH approximately 3 for a type 1 ("blue") copper protein, rusticyanin, obtained from the acidophilic organism Thiobacillus ferrooxidans. A combination of homonuclear proton and heteronuclear 15N-edited NMR spectra has been used to assign most of the 1H and 15N resonances of reduced rusticyanin. The copper-binding site is shown by analogy with other blue copper proteins to contain the side-chains of Cys138, His143 and Met148 at the C-terminal end of the sequence and a fourth ligand that is most likely a histidine, His85, consistent with the constitution of other type 1 copper sites. The global fold of the molecule is a compact beta-barrel or beta-sandwich, which contains a high proportion of beta-sheet secondary structure and a hydrophobic core particularly rich in aromatic residues. The copper-binding active site is surrounded by aromatic residues, and many of the resonances of the residues flanking the active site are shifted to unusual values, consistent with the effects of ring currents. The protected nature of the copper site is demonstrated by the large number of amide protons that are persistent in this region in 99% 2H2O solution at pH 3.4. We suggest that the unusual acid stability, both of the protein itself and of the blue copper active site, is a direct result of the protected and highly hydrophobic nature of the active site sequence and contacting loops and the high proportion of secondary structure in the protein.

A37812: N-methylstreptothricin F.

A37812, a new member of the streptothricin class of antibiotics, has been isolated and characterized as N-methylstreptothricin F. The structure elucidation of A37812 is based on results from 13C and 1H NMR spectroscopies.

Actaplanin, new glycopeptide antibiotics produced by Actinoplanes missouriensis. The isolation and preliminary chemical characterization of actaplanin.

Actaplanin (A4696), a new complex of broad spectrum Gram-positive antibiotics is produced by Actinoplanes missouriensis. High performance liquid chromatography was used to show that this complex is composed of several actaplanins. Hydrolytic experiments with acetaplanins A, B1, B2, B3, C1 and G showed that these actaplanins were composed of the same peptide core, an amino sugar and varying amounts of glucose, mannose and rhamnose. The neutral sugar content was determined for each actaplanin. A bioautographic study of aglycone formation during hydrolysis of the actaplanin complex showed that within a short time a simple mixture of two antimicrobially active hydrolysis products was obtained. These substances retained the antimicrobial spectrum and a high percentage of the antibiotic activity of the parent actaplanin complex. Methanolysis of the acetaplanin complex as well as the individual actaplanins resulted in the selective loss of the neutral sugar moieties and the isolation of actaplanin psi (pseudo)-aglycone--the core peptide which still retained an amino sugar group. The 1H NMR spectrum of this substance indicated a similarity to many features of ristocetin psi-aglycone. Hydrolytic studies showed that the amino sugar present in actaplanin was identical with L-ristosamine. It is concluded that the aglycone of actaplanin is a complex peptide composed of aromatic amino acids, and that the actaplanins each possess this aglycone and L-ristosamine but are differentiated by their neutral sugar composition.

A83586C, a new depsipeptide antibiotic.

A culture identified as Streptomyces karnatakensis was found to produce a novel cyclic hexadepsipeptide antibiotic designated A83586C. The structure was elucidated by X-ray crystallography, and full 1H and 13C NMR assignments are reported. The absolute configuration was confirmed by the detection of D-threonine in the acid hydrolysate of A83586C. A83586C had potent Gram-positive activity in vitro but lacked in vivo efficacy in mice.

A83016F, a new member of the aurodox family.

A new member of the aurodox family of antibiotics, A83016F, has been isolated from an unidentified actionmycete designated A83016. The structure and relative stereochemistry of A83016F were elucidated by NMR examination of the parent compound and its diacetate derivative. A83016F exhibits only weak antimicrobial activity.

Enzymatic and chemical modifications of lipopeptide antibiotic A21978C: the synthesis and evaluation of daptomycin (LY146032).

The novel lipopeptide antibiotic A21978C complex is active against Gram-positive organisms. This complex consists of a common peptide nucleus with various lipid acyl groups at the N-terminus characteristic of each individual factor. The fatty acid acyl group is removed by incubation of the A21978C complex with Actinoplanes utahensis to give the peptide nucleus. This peptide nucleus has the same amino acid sequence as A21978C. New analogs of A21978C were synthesized by acylation of the N-terminus of a tert-butoxycarbonyl (tert-BOC)-protected nucleus and subsequent deprotection. 1H NMR showed that the newly introduced acyl group was at the desired N-terminus. Three major groups of analogs were synthesized bearing fatty acid acyl, amino-aroyl and extended peptide side chains. Each analog was evaluated for antimicrobial activity and acute toxicity. Of these analogs, the n-decanoyl analog of A21978C (LY146032) gave the best survival in the mouse acute toxicity test at a high dose of 1,000 mg/kg, iv and was chosen for further study. This analog has been named daptomycin.

Synthesis of new analogs of echinocandin B by enzymatic deacylation and chemical reacylation of the echinocandin B peptide: synthesis of the antifungal agent cilofungin (LY121019).

The antifungal antibiotic, echinocandin B (ECB), was modified by a sequential procedure in which the initial step involved enzymatic removal of the native N-linoleoyl group from the N-terminus using an Actinoplanes utahensis culture. The resulting product, ECB nucleus, was reacylated using active esters or acid halides of various substituted acids to give a series of ECB analogs. These analogs possessed anti-Candida activity both in vitro and in vivo (mice). Other studies have shown that one of these, cilofungin, the 4-n-octyloxybenzoyl-ECB analog (LY121019), has excellent anti-Candida activity, low toxicity and is superior to other available antifungal antibiotics.

Structure elucidation of A58365A and A58365B, angiotensin converting enzyme inhibitors produced by Streptomyces chromofuscus.

A58365A and A58365B, angiotensin converting enzyme inhibitors isolated from the culture filtrate of Streptomyces chromofuscus NRRL 15098, are homologous compounds of molecular formulas C12H13NO6 and C13H15NO6. The molecular similarities of the two inhibitors were established by comparison of their 1H NMR, 13C NMR, and UV spectra. Catalytic hydrogenation of A58365A led to a tetrahydro-deoxy derivative, C12H17NO5; extensive 1H NMR decoupling studies at 360 MHz allowed all the non-exchangeable protons of the derivative to be connected in a continuous substructure. This fragment was combined with information from other spectroscopic methods to suggest the structures for A58365A (1) and A58365B (2); the conclusions were confirmed by an X-ray crystallographic analysis of A58365A-dimethyl ester.

Humor as a nursing intervention.

This article describes the use of humor as a nursing intervention and asks if nurses can justify the integration of the use of humor into the repertoire of nursing interventions. Several uses for humor are illustrated, and humor is differentiated from laughter. The article quotes many nurse leaders' opinions about humor and identifies do's and do not's of appropriate humor; it discusses six research studies in which health care professionals used humor as a treatment protocol. The studies were in the areas of preoperative teaching, clinical evaluation, strategies to prevent hopelessness in adolescents with oncologic illness, and group cohesiveness. Results of these six studies give some evidence, although not robust, that humor is an effective intervention. Methods of determining and implementing humor as an appropriate nursing intervention are included.

Digital subtraction angiography: patient preparation and care.

The use of digital subtraction angiography (DSA) is increasing. Nurses must be prepared to provide quality care to patients who have this relatively new method for radiographically studying the blood vessels. A description of DSA and its applications is provided. Patient preparation, assessment, teaching, and management are described. Complications of the procedure and their management are presented.

The relationship between height change and bone mineral density.

This pilot study was designed to determine if height loss would serve as an effective screening tool for osteoporosis. Height loss, bone density data, and fracture history were obtained from a patient population in a bone health clinic. The 76 subjects ranged from 25 to 88 years of age with mean age 60.4 years. Maximum height was established by the subject's recall and the height recorded on their driver's license. Current height was also assessed. Results indicate that excessive height loss does reflect low bone mass and may predict osteoporosis-related fractures.

Assessment of learning needs of registered nurses for osteoporosis education.

PURPOSE: To answer the questions: How important is osteoporosis education? What are the topics that must be included in osteoporosis education? DESIGN: Nonexperimental descriptive. SAMPLE: 225 questionnaires were distributed to Registered Nurses in acute, ambulatory, and long-term care; 139 (62%) responded. METHODS: Nurse experts in osteoporosis developed and refined a needs assessment questionnaire that was distributed by mail. The 5-page questionnaire included demographic items. Other items inquired about the respondent's perceived need for osteoporosis education for patients and nurses, and the respondent's knowledge of and need for education in 27 specific topics. FINDINGS: Respondents expressed strong interest in and need for an educational program on osteoporosis. They rated their (mean) knowledge of 22 of 27 specific topics as between "limited" and "adequate." Subjects delineated important core content to be included in the educational program. These subjects included risk factors, prevention, assessment, calcium intake, nutrition, menopause, pharmacotherapeutics, and fall prevention. CONCLUSIONS: Subjects found their own knowledge of certain topics in osteoporosis as less than adequate. Subjects documented the need for osteoporosis education for patients and nurses. IMPLICATIONS FOR NURSING EDUCATION: There is a need for continuing education offerings to inform nurses and patients about osteoporosis prevention, detection, and management.

Mitral valve prolapse: physical assessment complications and management.

This article presents the fundamental knowledge nurse practitioners need when managing the care of a client with mitral valve prolapse (MVP). The assessment discussion includes information on where and how to perform cardiac auscultation, and it also includes a discussion of the particular mid-to-late systolic click with murmur that is typical of MVP. Client preparation for diagnostic tests (echocardiogram and ECG) is also presented. Potential complications of endocarditis, mitral regurgitation, ventricular dysrhythmia, chest pain, systemic emboli and sudden death are discussed. Particular emphasis is given to the nursing management and client teaching that are required for clients with MVP. Nursing management includes teaching the client 1) the need and schedule for chemoprophylaxis of endocarditis, 2) how to maintain left ventricular volume, 3) the possible relationship between chest pain and hypovolemia and 4) the advantages of regular exercise. Changes in the click-murmur that may occur with pregnancy and the impact of MVP on contraception and childbearing decisions are discussed. Specific nursing diagnoses that may arise with the client with MVP are listed. Outcome criteria that may be used for evaluation of nursing care are provided.

Evaluation of bone resorption: a common problem during impaired mobility.

Osteoporosis, the result of an imbalance between bone resorption and bone formation, is a potential problem for the individual with a spinal cord injury because of the immobility commonly associated with this impairment. This study was performed to determine the diagnostic value of a new assay for urinary Pyridinium crosslink (UPyr). Assays were performed on 62 first morning voided and 50 24-hour urine specimens from clients in a bone health clinic. Higher than normal levels of UPyr were observed in females with osteoporosis. UPyr correlated well with urinary hydroxyproline (r = 0.429, p = 0.005; conversely, there was an inverse relationship between bone density and UPyr (r = -0.489, p = 0.01), positive correlation (r = 0.43, p = 0.011) between the 24-hour UPyr and a serum marker of bone resorption. The study confirms that UPyr has the ability to identify states of high bone resorption. This assay should be a welcome addition to the bone health assessment of individuals with risk factors such as impaired physical mobility.