A far-red-emitting ZnAl1.95Cr0.05O4 phosphor for plant growth LED applications

ZnAl_2-xCr_xO₄ (x = 0 and 0.05) samples were synthesized via a high-temperature solid-state reaction method. The structure, photoluminescence properties, EPR measurements, thermal stability, and chromaticity diagram of the far-red phosphor ZnAl_1.95Cr_0.05O₄ were investigated. These measurements have enabled us to study the Cr³⁺ transitions and the site symmetry of Cr³⁺ in the ZnAl₂O₄ host lattice and examine the suitability of ZnAl_1.95Cr_0.05O₄ for plant growth application. According to optical and EPR measurements, Cr³⁺ ions substitute Al³⁺ ions with D_3d symmetry in the ZnAl₂O₄ host. PLE measurement indicates that upon excitation at 390 nm and 530 nm, the far-red phosphor ZnAl_1.95Cr_0.05O₄ exhibited bright far-red emission around 687 nm. Photoluminescence phenomena show a sharp R line origin from the sublevels of the ²E_g(²G) → ⁴A₂(⁴F) transition in Cr³⁺ ions. The ²E_g level was split into ²E_g (Ē_g) and ²E_g (2Ā_g) levels in the distorted crystal field environment, and the sharp R line in the ZnAl₂O₄ matrix was split into R₁ and R₂ lines. In this paper, the temperature-dependent luminescence characteristics of ZnAl_1.95Cr_0.05O₄ have been investigated. As the temperature increased from 300 K to 440 K, a slight decrease in the intensity of the R1 and R2 lines was observed under excitation at 390 nm. The experimental results show that the ZnAl_1.95Cr_0.05O₄ phosphors exhibit a nearly zero-thermal-quenching behavior. The CIE chromaticity coordinates of the ZnAl_1.95Cr_0.05O₄ phosphor were located at the boundary of the chromaticity diagram, signifying that the phosphors possessed high color purity. The emissions of the ZnAl_1.95Cr_0.05O₄ phosphor match well with the PFR absorption of phytochromes in plants. The investigation indicates that ZnAl_1.95Cr_0.05O₄ is a potential far-red phosphor matching ultraviolet (UV) LED chips for plant growth applications.

Pharmacists' Perceptions on Nutritional Counseling of Oral Nutritional Supplements in the Community Pharmacy: An Exploratory Qualitative Study

Malnutrition has important health impacts, especially in the elderly. Oral nutritional supplements (ONS) are effective strategies to help balance the nutritional needs of malnourished persons. Multiple ONS are available at community pharmacies, enabling pharmacists to have the possibility to implement strategies for prevention and monitoring of malnourished patients. The aim of this study was to characterize the experience of community pharmacists with the counseling and follow-up of users of ONS. A sample of 19 pharmacists from 19 different community pharmacies were interviewed. Apart from dispensing ONS to support patients that are preparing for diagnostic tests, the most frequently mentioned clinical condition for ONS counseling was malnutrition and dysphagia. When pharmacists consider dispensing ONS, three themes emerge: patient care, related to counselling tailored ONS to each patient's needs; interprofessional collaboration, with a special focus in the collaboration with registered dietitians; and training and education on ONS, looking to improve their knowledge and skills in ONS counselling and follow-up. Future studies exploring new forms of interaction between pharmacists and dietitians in this context should be developed, aiming to determine the workflow of an interdisciplinary service addressing the needs of community dwelling malnourished patients.

Spinal Pain, Chronic Health Conditions and Health Behaviors: Data from the 2016-2018 National Health Interview Survey

Spinal pain and chronic health conditions are highly prevalent, burdensome, and costly conditions, both in the United States and globally. Using cross-sectional data from the 2016 through 2018 National Health Interview Survey (n = 26,926), we explored associations between spinal pain and chronic health conditions and investigated the influence that a set of confounders may have on the associations between spinal pain and chronic health conditions. Variance estimation method was used to compute weighted descriptive statistics and measures of associations with multinomial logistic regression models. All four chronic health conditions significantly increased the prevalence odds of spinal pain; cardiovascular conditions by 58%, hypertension by 40%, diabetes by 25% and obesity by 34%, controlling for all the confounders. For all chronic health conditions, tobacco use (45-50%), being insufficiently active (17-20%), sleep problems (180-184%), cognitive impairment (90-100%), and mental health conditions (68-80%) significantly increased the prevalence odds of spinal pain compared to cases without spinal pain. These findings provide evidence to support research on the prevention and treatment of non-musculoskeletal conditions with approaches of spinal pain management.

Bidirectional Comorbid Associations between Back Pain and Major Depression in US Adults

Low back pain and depression have been globally recognized as key public health problems and they are considered co-morbid conditions. This study explores both cross-sectional and longitudinal comorbid associations between back pain and major depression in the adult population in the United States. We used data from the Midlife in the United States survey (MIDUS), linking MIDUS II and III with a sample size of 2358. Logistic regression and Poisson regression models were used. The cross-sectional analysis showed significant associations between back pain and major depression. The longitudinal analysis indicated that back pain at baseline was prospectively associated with major depression at follow-up (PR 1.96, CI: 1.41, 2.74), controlling for health behavioral and demographic variables. Major depression at baseline was also prospectively associated with back pain at follow-up (PR 1.48, CI: 1.04, 2.13), controlling for a set of related confounders. These findings of a bidirectional comorbid association fill a gap in the current understanding of these comorbid conditions and could have clinical implications for the management and prevention of both depression and low back pain.

Magnetostructural coupling in RFeO3 (R = Nd, Tb, Eu and Gd)

We investigate the interplay of magnetization and lattice vibrations in rare-earth orthoferrites RFeO₃, with a specific focus on non-symmetry-breaking anomalies. To do so, we study the magnetization, magnon excitations and lattice dynamics as a function of temperature in NdFeO₃, TbFeO₃, EuFeO₃ and GdFeO₃. The magnetization shows distinct temperature anomalous behavior for all investigated rare-earth orthoferrites, even in the compounds with no phase transitions occurring at those temperatures. Through spin-phonon coupling, these magnetic changes are mirrored by the FeO₆ rotation mode for all the studied RFeO₃, revealing a common magnetostructural effect associated with the octahedra rotations. The R³⁺ oscillation modes evidence a Fe³⁺/R³⁺ spins cross-talk for the NdFeO₃ and TbFeO₃ cases. Our work sheds light into the common magnetostructural coupling in rare-earth orthoferrites, and the important role of magnetic anisotropy and spin-orbit coupling strength of the R-Fe interactions on the spin-reorientation transition at high temperatures.

Overview of conditions seen on a Canadian Memorial Chiropractic College outreach to the Dominican Republic

OBJECTIVE

This study aims to gather information on conditions seen, treatments rendered, and referrals made during a Canadian Memorial Chiropractic College outreach to the Dominican Republic serving those in need.

METHODS

Data was extracted from templated patient files retrospectively.

RESULTS

Spinal, extremity and other/whole body chief complaints accounted for 71.79%, 24.64% and 3.57% respectively in patients ranging in age from 1.5 to 106 years whose data was collected. Mechanical pain accounted for 95.07% of all cervical, 96.81% of thoracic and 91.27% of lumbar spine diagnoses. Various non-mechanical conditions were also encountered.Manual therapy was performed in 96.10% of cases. Twenty referrals were made to urgent care, six to a World Spine Care clinic and 46 for further investigation, including local medical doctors or surgery.

CONCLUSION

This study reports empirical data collected from an 11-day outreach to the Dominican Republic that provided otherwise unattainable chiropractic care for musculoskeletal complaints.

Coincidence? - Graves’ Disease & Thyroid Cancer

Background: DG coincidently with thyroid carcinoma has been reported as a rare phenomenon. It was thought that DG would be a protective condition in the development of cancer. However, published studies indicate the opposite, reporting an increased prevalence of differentiated thyroid cancer in DG compared to the general population. Some authors even report greater aggressiveness of this type of cancer in the presence of DG, with higher rates of, multifocality, metastatic disease and with a higher risk of recurrence. Clinical Case: Female, 46 years old, smoker 10 U.M.A., sent to the Endocrinology consultation due to symptomatic hyperthyroidism. No history of exposure to cervical radiotherapy, contact with iodinated products or cervical pain. Analytically, TSH <0.008 uUI / mL (0.27-4.2), free T4 4.09 ng/dL(0.93-1.70), free T3>20 pg/mL(2.57-4, 43), high levels of anti-thyroid and anti-TSH receptors 11.4IU/L (N <1.75), diagnosing with Graves’ disease. The thyroid ultrasound revealed a globose and hypervascularized thyroid. In the right hemithyroid, an echogenic nodular area of ​​ill-defined limits of about 12mm was identified, associated with some hyperechogenic elements. Bilateral cervical and submandibular lymph nodes were visualized with a short 8 mm axis, highlighting a ganglion in the right jugular chain, questioning the presence of millimeter echogenic foci. She started metibasol, with improved thyroid function and opted for ultrasound surveillance. Four months later, she repeated the ultrasound of the thyroid, maintaining a hypercogenic area, with ill-defined limits in the right lobe, with a 13mm longest axis. She also maintained adenopathies in the right jugulo-carotid chain, rounded, without hilum, the largest one with 13x9x17mm, and it was performed a fine needle aspiration of the ganglion. There was no measurement of thyroglobulin in the wash. The morphological changes were compatible with ganglion metastasis due to papillary thyroid carcinoma with a predominantly follicular pattern. She started 5% lugol solute, 7 drops every 8 hours for 8 days before surgery and underwent total thyroidectomy and central and lateral lymphadenectomy, with the identification of a mixed, multifocal papillary carcinoma. in the right lobe and isthmus, the microscopic size of the largest focus was 40mm, without invasion of the capsule or vascular invasion, with ganglion metastases in the lateral (9/46) and central district (6/6) (pT2N1b). She underwent treatment with I131 at a dose of 120mCi. Conclusion: This clinical case stands out for its uniqueness, given the simultaneity of Graves’ disease and thyroid cancer. The presence of cervical adenomegaly, which is rare in DG, increased clinical suspicion. Due to the increase of the adenopathy in a short period of time, we decided to perform a biopsy, which in this case was essential for the diagnosis and subsequent treatment.

Distance Management of Spinal Disorders During the COVID-19 Pandemic and Beyond: Evidence-Based Patient and Clinician Guides From the Global Spine Care Initiative

Background

The COVID-19 pandemic has greatly limited patients' access to care for spine-related symptoms and disorders. However, physical distancing between clinicians and patients with spine-related symptoms is not solely limited to restrictions imposed by pandemic-related lockdowns. In most low- and middle-income countries, as well as many underserved marginalized communities in high-income countries, there is little to no access to clinicians trained in evidence-based care for people experiencing spinal pain.

Objective

The aim of this study is to describe the development and present the components of evidence-based patient and clinician guides for the management of spinal disorders where in-person care is not available.

Methods

Ultimately, two sets of guides were developed (one for patients and one for clinicians) by extracting information from the published Global Spine Care Initiative (GSCI) papers. An international, interprofessional team of 29 participants from 10 countries on 4 continents participated. The team included practitioners in family medicine, neurology, physiatry, rheumatology, psychology, chiropractic, physical therapy, and yoga, as well as epidemiologists, research methodologists, and laypeople. The participants were invited to review, edit, and comment on the guides in an open iterative consensus process.

Results

The Patient Guide is a simple 2-step process. The first step describes the nature of the symptoms or concerns. The second step provides information that a patient can use when considering self-care, determining whether to contact a clinician, or considering seeking emergency care. The Clinician Guide is a 5-step process: (1) Obtain and document patient demographics, location of primary clinical symptoms, and psychosocial information. (2) Review the symptoms noted in the patient guide. (3) Determine the GSCI classification of the patient’s spine-related complaints. (4) Ask additional questions to determine the GSCI subclassification of the symptom pattern. (5) Consider appropriate treatment interventions.

Conclusions

The Patient and Clinician Guides are designed to be sufficiently clear to be useful to all patients and clinicians, irrespective of their location, education, professional qualifications, and experience. However, they are comprehensive enough to provide guidance on the management of all spine-related symptoms or disorders, including triage for serious and specific diseases. They are consistent with widely accepted evidence-based clinical practice guidelines. They also allow for adequate documentation and medical record keeping. These guides should be of value during periods of government-mandated physical or social distancing due to infectious diseases, such as during the COVID-19 pandemic. They should also be of value in underserved communities in high-, middle-, and low-income countries where there is a dearth of accessible trained spine care clinicians. These guides have the potential to reduce the overutilization of unnecessary and expensive interventions while empowering patients to self-manage uncomplicated spinal pain with the assistance of their clinician, either through direct in-person consultation or via telehealth communication.

Prevalence of Low Back Pain, Pelvic Girdle Pain, and Combination Pain in a Postpartum Ontario Population

OBJECTIVE

The purpose of this study was to determine the point prevalence of low back pain (LBP), pelvic girdle pain (PGP), and/or combination pain (COMBO pain) and period prevalence (presence or absence of any of those pains), as well as to identify risk factors at 1, 3, and 6 months postpartum in a Canadian population.

METHODS

Participants from a previous pregnancy study participated in a postpartum survey administered over the telephone at 1, 3, and 6 months following delivery. The survey included questions about LBP, PGP, or COMBO pain during the postpartum period, as well as questions related to risk factors (Canadian Task Force Classification II-3).

RESULTS

At 1, 3, and 6 months postpartum, responses from 46, 58, and 64 participants, respectively, demonstrated that 15%-21% of women experienced LBP and up to 4% of women experienced COMBO pain (point prevalence). At no time point was PGP reported to occur alone. Period prevalence of back pain for the participants returned to pre-pregnancy levels at each time point. Back pain during pregnancy was the only risk factor identified for back pain at 3 and 6 months postpartum.

CONCLUSION

This study demonstrated that 76% to 80% of respondents were pain free at 1, 3, and 6 months postpartum. Pregnancy-related back pain was the only risk factor associated with postpartum-related pain at the 1 to 3 and 3 to 6 month time interval. Identification of site-specific postpartum-related back pain may assist in determination of management and treatment plans for this population.

Prevalence of Low Back Pain, Pelvic Girdle Pain, and Combination Pain in a Pregnant Ontario Population

OBJECTIVE

The purpose of the current pilot study is to determine the point and period prevalence of site-specific back pain, low back pain (LBP), pelvic girdle pain (PGP), and combined pain (Combo Pain) in pregnant women at a large urban centre in Ontario.

METHODS

Point and period prevalence for LBP, PGP, and Combo Pain were determined using a questionnaire and accompanying pain diagram. Women were included in the study if they were healthy, of child-bearing age (18-45 years), currently experiencing a singleton pregnancy (any trimester), and proficient in the English language.

RESULTS

Data collected from 287 women were included in the analysis. Three-quarters of women suffered from some sort of pregnancy-related back pain. The point and period prevalences for women who were experiencing LBP, PGP, and Combo Pain were 15.7%, 17.8%, and 15.3% and 33.4%, 27.9%, and 30.7%, respectively. Secondary analyses demonstrated that increasing GA and suffering from both pains at some point prior to pregnancy (Prior Both) increased the risk of experiencing PGP and Combo Pain during pregnancy, respectively.

CONCLUSION

The current study demonstrates that 76% of sampled women experienced pregnancy-related back pain and the prevalence of site-specific pain (LBP, PGP, and Combo Pain) increases with increased gestation. Risk factors include advanced GA and experiencing both types of pain prior to pregnancy (Prior Both). Furthermore, it is suggested that a standard definition of pain by location should be developed and employed so that future studies can elucidate appropriate prevention strategies and treatment options for each.

Laparoscopic pediatric pyeloplasty using the Flexdex® articulating needle driver: step-by-step video

Ureteropelvic junction (UPJ) stenosis is the most common cause of pathological neonatal hydronephrosis. UPJ obstruction may be treated conservatively in some cases, but surgery is indicated if symptoms occur or renal function deteriorates. Pyeloplasty is the procedure of choice for UPJ stenosis. Pyeloplasty can be performed by open laparoscopic or robotic technique. The laparoscopic technique is safe and may be associated with shorter length of hospital stay and reduced complications. Lately, robotic pyeloplasty has been performed with similar results, adding the benefits of easier suturing maneuverability, but with increased costs. Flexdex® is a laparoscopic articulating needle driver that improves maneuverability and ergonomics. In this video, a laparoscopic pyeloplasty with the Flexdex® needle drive is described. The case was treated without any intraoperative complications and with no significant blood loss, and the patient was discharged the day after the procedure. After 90 days of follow-up, there were no complications reported.

The Global Spine Care Initiative: World Spine Care executive summary on reducing spine-related disability in low- and middle-income communities

PURPOSE

Spinal disorders, including back and neck pain, are major causes of disability, economic hardship, and morbidity, especially in underserved communities and low- and middle-income countries. Currently, there is no model of care to address this issue. This paper provides an overview of the papers from the Global Spine Care Initiative (GSCI), which was convened to develop an evidence-based, practical, and sustainable, spinal healthcare model for communities around the world with various levels of resources.

METHODS

Leading spine clinicians and scientists around the world were invited to participate. The interprofessional, international team consisted of 68 members from 24 countries, representing most disciplines that study or care for patients with spinal symptoms, including family physicians, spine surgeons, rheumatologists, chiropractors, physical therapists, epidemiologists, research methodologists, and other stakeholders.

RESULTS

Literature reviews on the burden of spinal disorders and six categories of evidence-based interventions for spinal disorders (assessment, public health, psychosocial, noninvasive, invasive, and the management of osteoporosis) were completed. In addition, participants developed a stratification system for surgical intervention, a classification system for spinal disorders, an evidence-based care pathway, and lists of resources and recommendations to implement the GSCI model of care.

CONCLUSION

The GSCI proposes an evidence-based model that is consistent with recent calls for action to reduce the global burden of spinal disorders. The model requires testing to determine feasibility. If it proves to be implementable, this model holds great promise to reduce the tremendous global burden of spinal disorders. These slides can be retrieved under Electronic Supplementary Material.

The Global Spine Care Initiative: methodology, contributors, and disclosures

PURPOSE

The purpose of this report is to describe the Global Spine Care Initiative (GSCI) contributors, disclosures, and methods for reporting transparency on the development of the recommendations.

METHODS

World Spine Care convened the GSCI to develop an evidence-based, practical, and sustainable healthcare model for spinal care. The initiative aims to improve the management, prevention, and public health for spine-related disorders worldwide; thus, global representation was essential. A series of meetings established the initiative's mission and goals. Electronic surveys collected contributorship and demographic information, and experiences with spinal conditions to better understand perceptions and potential biases that were contributing to the model of care.

RESULTS

Sixty-eight clinicians and scientists participated in the deliberations and are authors of one or more of the GSCI articles. Of these experts, 57 reported providing spine care in 34 countries, (i.e., low-, middle-, and high-income countries, as well as underserved communities in high-income countries.) The majority reported personally experiencing or having a close family member with one or more spinal concerns including: spine-related trauma or injury, spinal problems that required emergency or surgical intervention, spinal pain referred from non-spine sources, spinal deformity, spinal pathology or disease, neurological problems, and/or mild, moderate, or severe back or neck pain. There were no substantial reported conflicts of interest.

CONCLUSION

The GSCI participants have broad professional experience and wide international distribution with no discipline dominating the deliberations. The GSCI believes this set of papers has the potential to inform and improve spine care globally. These slides can be retrieved under Electronic Supplementary Material.

Intra-examiner reliability of measurements of ankle range of motion using a modified inclinometer: a pilot study

A modified inclinometer was designed for measuring total ankle range of motion (ROM) in the standing position for a large future study. The purpose of this pilot study was to assess the intra-examiner reliability of this new device in order to see if the examiner would be able to produce equally reliable measurements with this instrument as with a routinely used goniometer. Nineteen young healthy individuals took part in the pilot. The same examiner took the ROM measurements using both devices twice on the same day and one further time 2 or 3 days later. Test-retest reliability was measured using the intraclass correlation coefficient (ICC). The ICC values were 0.86 (95% CI=[0.67; 0.94]) and 0.83 (95% CI=[0.61; 0.93]) for the measurements taken with the goniometer on the same day and for those on two different days. The corresponding values for the modified inclinometer were 0.88 (95% CI=[0.72;0.95]) and 0.81 (95% CI=[0.57; 0.92]). Both instruments were found to have very good test-retest reliability.

Profamille, programme de psychoéducation pour les familles d’un proche souffrant de schizophrénie : étude de l’impact du programme sur l’humeur des participants

Profamille est un programme psychoéducatif destiné aux aidants naturels des patients souffrant de schizophrénie. Il est standardisé, évalué et l’un des plus utilisés dans la francophonie. Il s’appuie sur des recherches sur les interactions entre le milieu familial et le cours de la maladie. L’une de ses particularités est de considérer l’action ciblée sur l’humeur des aidants comme l’un des paramètres essentiels de ses résultats positifs. En effet, l’amélioration de l’humeur doit permettre l’amélioration du coping des aidants, du climat émotionnel au sein de la famille et de l’acquisition des nouvelles connaissances délivrées par le programme. À notre connaissance, une seule étude antérieure sur l’évolution de l’humeur des participants à Profamille a été publiée, et elle concernait une version ancienne du programme. L’objectif de notre étude a donc été d’évaluer l’impact de Profamille sur l’humeur de 57 aidants inclus lors de 4 sessions ayant eu lieu au CHU de Caen, entre 2010 et 2014, grâce à un auto-questionnaire rempli en début et fin de programme (Center for Epidemiologic Studies-Depression scale [CES-D]). Nous avons distingué pour la comparaison statistique des scores d’évaluation (test de Wilcoxon bilatéral sur les données appariées) 3 groupes :

Les résultats ont montré que l’humeur s’améliorait tant dans le groupe à risque de syndrome dépressif (p < 0,001) que dans le groupe très probablement dépressif (p < 0,001). La comparaison des scores de l’humeur dans le groupe des sujets non déprimés n’était pas statistiquement significative. Ces résultats confirment l’impact positif de Profamille sur l’humeur des participants et son intérêt fondamental dans le travail avec les familles de nos patients souffrant de schizophrénie.

Do semantic categories activate distinct cortical regions? Evidence for a distributed neural semantic system

A key issue in cognitive neuroscience concerns the neural representation of conceptual knowledge. Currently, debate focuses around the issue of whether there are neural regions specialised for the processing of specific semantic attributes or categories, or whether concepts are represented in an undifferentiated neural system. Neuropsychological studies of patients with selective semantic deficits and previous neuroimaging studies do not unequivocally support either account. We carried out a PET study to determine whether there is any regional specialisation for the processing of concepts from different semantic categories using picture stimuli and a semantic categorisation task. We found robust activation of a large semantic network extending from left inferior frontal cortex into the inferior temporal lobe and including occipital cortex and the fusiform gyrus. The only category effect that we found was additional activation for animals in the right occipital cortex, which we interpret as being due to the extra visual processing demands required in order to differentiate one animal from another. We also carried out analyses in specific cortical regions that have been claimed to be preferentially activated for various categories, but found no evidence of any differential activation as a function of category. We interpret these data within the framework of cognitive accounts in which conceptual knowledge is represented within a nondifferentiated distributed system.

IL1 gene polymorphisms and unsuccessful dental implants

OBJECTIVES

This study aimed to analyse the association between polymorphisms in the IL1 gene cluster and failure of dental implants in a Portuguese population.

MATERIAL AND METHODS

A total of 155 Caucasian Portuguese subjects were divided into two groups: 100 with successful dental implants and 55 with unsuccessful dental implants. DNA was obtained through an oral mucosa scraping. PCR was used to identify the polymorphisms: single nucleotide changes in positions -889 of IL1A gene and +3953 of IL1B gene.

RESULTS

The prevalence of the polymorphisms -889IL1A gene and +3953IL1B gene, determined by the positive result of TGP (Genetic Test for Periodontitis; CGC, Genetics, Portugal), in the studied population rehabilitated with dental implants was of 33.50%. Allele 1 of the IL1B gene was the most prevalent (62.20%), followed by allele 1 of the IL1A gene (54.80%) and the least frequent was allele 2 of IL1B gene (37.40%). Success of dental implants was mainly associated with a negative TGP result, whereas no success was found to be related to a positive result. There were no statistically significant differences between the alleles 1 and 2 of the genes IL1A and IL1B and the tobacco and alcohol consumption for the success or no success of the dental implants.

CONCLUSIONS

The alleles 1 and 2 of IL1A gene and the alleles 1 and 2 of IL1B gene were statistically associated with the success or no success of the dental implants. Tobacco habit and alcohol consumption showed no statistically significant association with success or no success of the dental implants.

Metalloenzymes of the denitrification pathway

Denitrification, or dissimilative nitrate reduction, is an anaerobic process used by some bacteria for energy generation. This process is important in many aspects, but its environmental implications have been given particular relevance. Nitrate accumulation and release of nitrous oxide in the atmosphere due to excess use of fertilizers in agriculture are examples of two environmental problems where denitrification plays a central role. The reduction of nitrate to nitrogen gas is accomplished by four different types of metalloenzymes in four simple steps: nitrate is reduced to nitrite, then to nitric oxide, followed by the reduction to nitrous oxide and by a final reduction to dinitrogen. In this manuscript we present a concise updated review of the bioinorganic aspects of denitrification.

Differential expression of allergens on the internal and external surfaces of latex surgical gloves

BACKGROUND

Differences in latex allergen sensitization profiles have been described between children undergoing repeated surgical interventions and health care workers. The purpose of this study was to determine whether such sensitization profiles are associated with differences in the expression of latex allergen between the internal and external surfaces of surgical gloves.

METHODS

Extracts were obtained from whole surgical gloves as well as from their external and internal surfaces. The extracts were centrifuged, filtered, concentrated, dialyzed and lyophilized. The protein profile of the extracts was analyzed using hydrophobic interaction chromatography (HIC) and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Immunoblotting was performed using sera from two patients with confirmed latex allergy. Latex recombinant allergen-specific IgE in these two patients was determined using a fluorescence enzyme immunoassay (FEIA) method. Latex allergen quantification was determined on both glove surfaces using an ELISA method.

RESULTS

HIC and SDS-PAGE showed qualitative and quantitative differences in proteins between the internal and external glove surfaces, with the former being much richer in proteins. Immunoblotting of glove extracts using sera from two latex-allergic health workers showed differences between glove surface extracts. ELISA quantification of latex allergens demonstrated that the internal glove surface had high amounts of Hev b 5 and Hev b 6.02 whereas the external surface showed Hev b 1, Hev b 3, and Hev b 6.02.

CONCLUSIONS

Our results reveal substantial differences in the composition of latex allergen profiles between the internal and external surfaces of surgical latex gloves, which may suggest a relationship between latex allergen localization and sensitization routes in different risk groups.

Effect of spermine and DNase on DNA release from bacteriophage T5

Bacterial viruses (bacteriophages) consist of nucleic acid protected by a protein envelope called capsid. At the start of infection, the phage genome is translocated into the bacterial cytoplasm. In vitro (and also in vivo), this DNA release can be triggered by binding a specific receptor protein to the phage tail. The force responsible for the release arises from energy stored in the capsid due to strong confinement of the DNA. We show that this force can be modified by adding molecules like spermine that affect DNA conformation. The tetravalent cation spermine can reduce the pressure inside the capsid and induce condensation of the released DNA. We examine the effect of spermine on DNA ejection from phage T5 by using light scattering and gel electrophoresis to measure the amount of DNA remaining in the capsid at the end of ejection. We discuss the results in terms of free energy minimization and we demonstrate that the presence of a DNA condensate outside the phage generates an additional force pulling passively on the DNA remaining inside the capsid.

Circadian and seasonal variation of endogenous ubiquinone plasma level

Coenzyme Q10 (CoQ10) or ubiquinone, a redox component of the mitochondrial electron transport chains, is a powerful antioxidant and membrane stabilizer that may prevent cellular damage during myocardial ischemia and reperfusion therapy. Coenzyme Q10 has been used primarily as an adjuvant therapy for some cardiomyopathies. However, one of the main problems in CoQ10 administration is the high variability of endogenous plasma and tissue levels, which seems to be dependent on several factors. This work explores temporal 24h and seasonal variation as well as gender and racial differences in endogenous plasma ubiquinone concentration. Coenzyme Q10 measurements (quantified by HPLC-UV) of 16 healthy volunteers were done during the daytime hours of activity beginning at 09:00h one day and ending at 09:00h the next day (13 different determinations) in two distinct months. April and October, of the year. A statistically significant circadian rhythm in plasma ubiquinone concentration that includes only the fundamental 24h component was demonstrated both in the April and October data. Furthermore, the time-point means of the ubiquinone concentration in the October study were invariably higher than those obtained in the April study. No statistically significant differences were found in CoQ10 concentration between male and female subjects, both in April and in October. In addition, racial differences were demonstrated; lower plasma ubiquinone levels were found in Caucasian compared to African subjects. However, the latter small group of subjects failed to demonstrate a circadian rhythm, neither in the April nor in the October analysis.

Respiratory mechanics and morphometric changes during anesthesia with ketamine in normal rats

Ketamine is believed to reduce airway and pulmonary tissue resistance. The aim of the present study was to determine the effects of ketamine on the resistive, elastic and viscoelastic/inhomogeneous mechanical properties of the respiratory system, lungs and chest wall, and to relate the mechanical data to findings from histological lung analysis in normal animals. Fifteen adult male Wistar rats were assigned randomly to two groups: control (N = 7) and ketamine (N = 8). All animals were sedated (diazepam, 5 mg, ip) and anesthetized with pentobarbital sodium (20 mg/kg, ip) or ketamine (30 mg/kg, ip). The rats were paralyzed and ventilated mechanically. Ketamine increased lung viscoelastic/inhomogeneous pressure (26%) compared to the control group. Dynamic and static elastances were similar in both groups, but the difference was greater in the ketamine than in the control group. Lung morphometry demonstrated dilation of alveolar ducts and increased areas of alveolar collapse in the ketamine group. In conclusion, ketamine did not act at the airway level but acted at the lung periphery increasing mechanical inhomogeneities possibly resulting from dilation of distal airways and alveolar collapse.

Structural organisation of the head-to-tail interface of a bacterial virus

In tailed icosahedral bacteriophages the connection between the 5-fold symmetric environment of the portal vertex in the capsid and the 6-fold symmetric phage tail is formed by a complex interface structure. The current study provides the detailed analysis of the assembly and structural organisation of such an interface within a phage having a long tail. The region of the interface assembled as part of the viral capsid (connector) was purified from DNA-filled capsids of the Bacillus subtilis bacteriophage SPP1. It is composed of oligomers of gp6, the SPP1 portal protein, of gp15, and of gp16. The SPP1 connector structure is formed by a mushroom-like portal protein whose cap faces the interior of the viral capsid in intact virions, an annular structure below the stem of the mushroom, and a second narrower annulus that is in direct contact with the helical tail extremity. The layered arrangement correlates to the stacking of gp6, gp15, and gp16 on top of the tail. The gp16 ring is exposed to the virion outside. During SPP1 morphogenesis, gp6 participates in the procapsid assembly reaction, an early step in the assembly pathway, while gp15 and gp16 bind to the capsid portal vertex after viral chromosome encapsidation. gp16 is processed during or after tail attachment to the connector region. The portal protein gp6 has 12-fold cyclical symmetry in the connector structure, whereas assembly-naïve gp6 exhibits 13-fold symmetry. We propose that it is the interaction of gp6 with other viral morphogenetic proteins that drives its assembly into the 12-mer state.

Evaluation of carboxymethylcellulose, hydroxypropylmethylcellulose, and aluminum hydroxide as potential carriers for rhBMP-2

Conventional iliac crest nonvascularized corticocancelous bone grafts and bone flaps have been used to treat bony defects. However, these treatments have some limitations, namely, the availability of donor tissue, donor site morbidity, difficulty to shape the bone flap to the defect, and complexity of the surgery. The bone morphogenetic protein (rhBMP-2) is osteoinductive. However, its implantation requires a matrix (carrier) in order to define the shape of the resulting bone and to retain the protein at the site for the time required for induction to occur. When the ideal carrier is found, an unlimited supply of material would be available for all applications where bone is needed. In this in vitro study, we evaluated the suitability of some potential carriers for rhBMP-2 by measuring the alkaline phosphatase (ALP) activity of fibroblast cultures. Either rhBMP-2 or sodium carboxymethylcellulose significantly increased the ALP activity, when used alone. When sodium carboxymethylcellulose was combined with rhBMP-2, there was an increase in the ALP activity, but lower than those obtained when the products were used alone. Hydroxypropylmethylcellulose alone did not affect ALP activity. However, the combination of rhBMP-2 with hydroxypropylmethylcellulose did not increase the ALP activity, despite the presence of rhBMP-2. Aluminium hydroxide proved to be an unsuitable rhBMP-2 adsorbent.

Substitution of murine ferrochelatase glutamate-287 with glutamine or alanine leads to porphyrin substrate-bound variants

Ferrochelatase (EC 4.99.1.1) is the terminal enzyme of the haem biosynthetic pathway and catalyses iron chelation into the protoporphyrin IX ring. Glutamate-287 (E287) of murine mature ferrochelatase is a conserved residue in all known sequences of ferrochelatase, is present at the active site of the enzyme, as inferred from the Bacillus subtilis ferrochelatase three-dimensional structure, and is critical for enzyme activity. Substitution of E287 with either glutamine (Q) or alanine (A) yielded variants with lower enzymic activity than that of the wild-type ferrochelatase and with different absorption spectra from the wild-type enzyme. In contrast to the wild-type enzyme, the absorption spectra of the variants indicate that these enzymes, as purified, contain protoporphyrin IX. Identification and quantification of the porphyrin bound to the E287-directed variants indicate that approx. 80% of the total porphyrin corresponds to protoporphyrin IX. Significantly, rapid stopped-flow experiments of the E287A and E287Q variants demonstrate that reaction with Zn(2+) results in the formation of bound Zn-protoporphyrin IX, indicating that the endogenously bound protoporphyrin IX can be used as a substrate. Taken together, these findings suggest that the structural strain imposed by ferrochelatase on the porphyrin substrate as a critical step in the enzyme catalytic mechanism is also accomplished by the E287A and E287Q variants, but without the release of the product. Thus E287 in murine ferrochelatase appears to be critical for the catalytic process by controlling the release of the product.

Differential effects of eprosartan and losartan at prejunctional angiotensin II receptors

A comparison was made of the influence of losartan and eprosartan on angiotensin II effects at pre- and postjunctional receptors of the canine pulmonary artery and at prejunctional receptors of the rat left ventricle. To study postjunctional contractile responses to angiotensin II, non-cumulative concentration-response curves were determined; to study prejunctional effects of angiotensin II, the tissues were preincubated with [3H]noradrenaline and then superfused and electrically stimulated (1 Hz, 2 ms, 50 mA, 5 min). Postjunctionally, both losartan and eprosartan caused a parallel shift of the concentration-response curve of angiotensin II to the right (pKd of 8.15 and 8.28, respectively). At the prejunctional level, while eprosartan, in concentrations similar to those which were effective postjunctionally (30-100 nM), antagonized the facilitatory effect on noradrenaline release in both the dog pulmonary artery and the rat ventricle, losartan was ineffective in concentrations up to 1 microM. It is concluded that pre-junctional receptors for angiotensin II in the canine pulmonary artery and in the rat left ventricle are different from postjunctional receptors of the canine pulmonary artery. It is proposed that the prejunctional receptors of these tissues are atypical AT1 or "AT1B-like" receptors.

Mössbauer characterization of the iron-sulfur clusters in Desulfovibrio vulgaris hydrogenase

The periplasmic hydrogenase of Desulfovibrio vulgaris (Hildenbourough) is an all Fe-containing hydrogenase. It contains two ferredoxin type [4Fe-4S] clusters, termed the F clusters, and a catalytic H cluster. Recent X-ray crystallographic studies on two Fe hydrogenases revealed that the H cluster is composed of two sub-clusters, a [4Fe-4S] cluster ([4Fe-4S](H)) and a binuclear Fe cluster ([2Fe](H)), bridged by a cysteine sulfur. The aerobically purified D. vulgaris hydrogenase is stable in air. It is inactive and requires reductive activation. Upon reduction, the enzyme becomes sensitive to O(2), indicating that the reductive activation process is irreversible. Previous EPR investigations showed that upon reoxidation (under argon) the H cluster exhibits a rhombic EPR signal that is not seen in the as-purified enzyme, suggesting a conformational change in association with the reductive activation. For the purpose of gaining more information on the electronic properties of this unique H cluster and to understand further the reductive activation process, variable-temperature and variable-field Mössbauer spectroscopy has been used to characterize the Fe-S clusters in D. vulgaris hydrogenase poised at different redox states generated during a reductive titration, and in the CO-reacted enzyme. The data were successfully decomposed into spectral components corresponding to the F and H clusters, and characteristic parameters describing the electronic and magnetic properties of the F and H clusters were obtained. Consistent with the X-ray crystallographic results, the spectra of the H cluster can be understood as originating from an exchange coupled [4Fe-4S]-[2Fe] system. In particular, detailed analysis of the data reveals that the reductive activation begins with reduction of the [4Fe-4S](H) cluster from the 2+ to the 1+ state, followed by transfer of the reducing equivalent from the [4Fe-4S](H) subcluster to the binuclear [2Fe](H) subcluster. The results also reveal that binding of exogenous CO to the H cluster affects significantly the exchange coupling between the [4Fe-4S](H) and the [2Fe](H) subclusters. Implication of such a CO binding effect is discussed.

Mössbauer characterization of the iron-sulfur clusters in Desulfovibrio vulgaris hydrogenase

The periplasmic hydrogenase of Desulfovibrio vulgaris (Hildenbourough) is an all Fe-containing hydrogenase. It contains two ferredoxin type [4Fe-4S] clusters, termed the F clusters, and a catalytic H cluster. Recent X-ray crystallographic studies on two Fe hydrogenases revealed that the H cluster is composed of two sub-clusters, a [4Fe-4S] cluster ([4Fe-4S](H)) and a binuclear Fe cluster ([2Fe](H)), bridged by a cysteine sulfur. The aerobically purified D. vulgaris hydrogenase is stable in air. It is inactive and requires reductive activation. Upon reduction, the enzyme becomes sensitive to O(2), indicating that the reductive activation process is irreversible. Previous EPR investigations showed that upon reoxidation (under argon) the H cluster exhibits a rhombic EPR signal that is not seen in the as-purified enzyme, suggesting a conformational change in association with the reductive activation. For the purpose of gaining more information on the electronic properties of this unique H cluster and to understand further the reductive activation process, variable-temperature and variable-field Mössbauer spectroscopy has been used to characterize the Fe-S clusters in D. vulgaris hydrogenase poised at different redox states generated during a reductive titration, and in the CO-reacted enzyme. The data were successfully decomposed into spectral components corresponding to the F and H clusters, and characteristic parameters describing the electronic and magnetic properties of the F and H clusters were obtained. Consistent with the X-ray crystallographic results, the spectra of the H cluster can be understood as originating from an exchange coupled [4Fe-4S]-[2Fe] system. In particular, detailed analysis of the data reveals that the reductive activation begins with reduction of the [4Fe-4S](H) cluster from the 2+ to the 1+ state, followed by transfer of the reducing equivalent from the [4Fe-4S](H) subcluster to the binuclear [2Fe](H) subcluster. The results also reveal that binding of exogenous CO to the H cluster affects significantly the exchange coupling between the [4Fe-4S](H) and the [2Fe](H) subclusters. Implication of such a CO binding effect is discussed.

Redox potential measurements of the Mycobacterium tuberculosis heme protein KatG and the isoniazid-resistant enzyme KatG(S315T): insights into isoniazid activation

Mycobacterium tuberculosis KatG is a multifunctional heme enzyme responsible for activation of the antibiotic isoniazid. A KatG(S315T) point mutation is found in >50% of isoniazid-resistant clinical isolates. Since isoniazid activation is thought to involve an oxidation reaction, the redox potential of KatG was determined using cyclic voltammetry, square wave voltammetry, and spectroelectrochemical titrations. Isoniazid activation may proceed via a cytochrome P450-like mechanism. Therefore, the possibility that substrate binding by KatG leads to an increase in the heme redox potential and the possibility that KatG(S315T) confers isoniazid resistance by altering the redox potential were examined. Effects of the heme spin state on the reduction potentials of KatG and KatG(S315T) were also determined. Assessment of the Fe(3+)/Fe(2+) couple gave a midpoint potential of ca. -50 mV for both KatG and KatG(S315T). In contrast to cytochrome P450s, addition of substrate had no significant effect on either the KatG or KatG(S315T) redox potential. Conversion of the heme to a low-spin configuration resulted in a -150 to -200 mV shift of the KatG and KatG(S315T) redox potentials. These results suggest that isoniazid resistance conferred by KatG(S315T) is not mediated through changes in the heme redox potential. The redox potentials of isoniazid were also determined using cyclic and square wave voltammetry, and the results provide evidence that the ferric KatG and KatG(S315T) midpoint potentials are too low to promote isoniazid oxidation without formation of a high-valent enzyme intermediate such as compounds I and II or oxyferrous KatG.

Role of calcium in gentamicin-induced mesangial cell activation

Gentamicin-induced decreases in glomerular filtration rate have been associated to a marked decline in the glomerular capillary ultrafiltration coefficient which could be due to an active contraction of mesangial cells. In the present work we assessed a possible role of cytosolic Ca2+ as a mediator that leads to contraction and proliferation induced by gentamicin on mesangial cells. Gentamicin (10(-5)M) induced an increase in cytosolic free Ca2+, that was fully inhibited by the calcium channel blocker, verapamil, and by the endoplasmic reticulum calcium release blocker, TMB8. Gentamicin induced a planar surface area reduction in cultured mesangial cells, that was blunted by verapamil and TMB-8. Gentamicin also stimulated [3H]thymidine incorporation into DNA and increased viable cell number, effects that were reduced by both, verapamil and TMB-8. Gentamicin stimulated the expression of the AP1 protein; this expression was partially blunted by verapamil and TMB-8. Moreover, verapamil inhibited gentamicin-induced PAF synthesis from mesangial cells. In summary, gentamicin directly raised intracellular Ca2+ activating both calcium influx from external medium and calcium release from internal stores. This increase is responsible of cellular activation (contraction and proliferation) and PAF synthesis induced by gentamicin on mesangial cells.

Platelet activation is increased in cyclosporin A-induced hypertensive rats

One of the most severe side effects of the immunosuppressive agent, cyclosporin A (CsA), is increased risk of thromboembolic complications and drug-related hypertension. Because platelets might be involved in these processes, we tested the possibility of CsA affecting platelet activation, which might contribute to these adverse drug reactions. The experiments were done using Wistar rats, treated or not (control) with CsA (Sandimmun Neoral), 5 and 30 mg/kg/day, for 7 weeks. Systolic, diastolic, and mean blood pressures, intracellular free calcium concentration ([Ca2+]i), platelet serotonin (5-HT) contents, and aggregation were determined, at weeks 0, 2, and 7 of treatment. Inositol phosphates (InsP) production, platelet thromboxane A2 (TXA2) generation, and morphology of platelets, through electron microscopy studies, also were compared. It was demonstrated that blood pressures increased in the CsA-treated groups, when compared with the control group, after 2 and 7 weeks of administration. CsA at both "attack" and "maintenance" doses increased basal, 5-HT, and thrombin-evoked [Ca2+]i after 2 and 7 weeks versus the control group. However, basal and evoked InsP production was stimulated by 5 mg/kg of CsA, but inhibited by 30 mg/kg, when compared with the control. Platelet 5-HT contents decreased significantly after 2 and 7 weeks in the CsA-treated groups, when compared with the control group. Collagen-induced whole blood platelet aggregation increased drastically in the "attack" CsA-treated group, whereas adenosine diphosphate (ADP)-induced platelet aggregation did not reach statistical significance. Finally, in vitro basal, collagen-, and ADP-evoked platelet TXA2 generation increased in both CsA concentrations, versus the control. In conclusion, our study demonstrates that both CsA doses alter platelet calcium homeostasis (even affecting the calcium fluxes differently), 5-HT and TXA2 contents and aggregation, which might contribute to the development and/or maintenance of high blood pressures and increased risk of thromboembolic complications.

Cell polarization and adhesion in a motile pathogenic protozoan: role and fate of the Entamoeba histolytica Gal/GalNAc lectin

The human pathogenic protozoan Entamoeba histolytica is a motile cell polarized into a front pseudopod and a rear uroid. The amoebic Gal/GalNAc surface lectin is a major adhesion molecule composed of an immunodominant 170-kDa heavy subunit, mostly extracellular except for a short cytoplasmic tail, and of an extracellular light subunit. The binding of multivalent ligands triggers lectin capping and recruitment to the uroid. The properties of the Gal/GalNAc lectin and its role in amoeba adhesion and uroid polarization are reviewed in the context of the molecular mechanisms underlying cell polarization and locomotion.

Improved bioavailability of a micronized megestrol acetate tablet formulation in humans

Megestrol acetate, a progestogen widely used in the palliative treatment of endometrial carcinoma and breast cancer, is currently administered orally as a solid dosage form. Bioavailability of the drug following oral administration is closely related to the effectiveness and safety profile of the drug in formulation. Improved immediate-release formulations should allow improved drug delivery into the systemic circulation and, at the end, to the site of action. The micronization of drugs is one of the technological procedures to achieve such a purpose. This paper reports the design and results obtained in an in vivo study of the bioavailability of a micronized megestrol acetate tablet formulation compared to a conventional form. A significant increase in the drug bioavailability was observed, in either the rate or the extent of absorption. In vitro dissolution data of the two study formulations reflected the in vivo findings.

Purification, characterization, and preliminary crystallographic study of copper-containing nitrous oxide reductase from Pseudomonas nautica 617

The aerobic purification of Pseudomonas nautica 617 nitrous oxide reductase yielded two forms of the enzyme exhibiting different chromatographic behaviors. The protein contains six copper atoms per monomer, arranged in two centers named Cu(A) and Cu(Z). Cu(Z) could be neither oxidized nor further reduced under our experimental conditions, and exhibits a 4-line EPR spectrum (g(x)=2.015, A(x)=1.5 mT, g(y)=2.071, A(y)=2 mT, g(z)=2.138, A(z)=7 mT) and a strong absorption at approximately 640 nm. Cu(A) can be stabilized in a reduced EPR-silent state and in an oxidized state with a typical 7-line EPR spectrum (g(x)=g(y)= 2.021, A(x) = A(y)=0 mT, g(z) = 2.178, A(z)= 4 mT) and absorption bands at 480, 540, and approximately 800 nm. The difference between the two purified forms of nitrous oxide reductase is interpreted as a difference in the oxidation state of the Cu(A) center. In form A, Cu(A) is predominantly oxidized (S = (1)/(2), Cu(1.5+)-Cu(1.5+)), while in form B it is mostly in the one-electron reduced state (S = 0, Cu(1+)-Cu(1+)). In both forms, Cu(Z) remains reduced (S = 1/2). Complete crystallographic data at 2.4 A indicate that Cu(A) is a binuclear site (similar to the site found in cytochrome c oxidase) and Cu(Z) is a novel tetracopper cluster [Brown, K., et al. (2000) Nat. Struct. Biol. (in press)]. The complete amino acid sequence of the enzyme was determined and comparisons made with sequences of other nitrous oxide reductases, emphasizing the coordination of the centers. A 10.3 kDa peptide copurified with both forms of nitrous oxide reductase shows strong homology with proteins of the heat-shock GroES chaperonin family.

In vitro packaging of DNA of the Bacillus subtilis bacteriophage SPP1

In vitro packaging of bacteriophage SPP1 DNA into procapsids is described and the requirements of this process were determined. Combination of proheads with an extract supplying terminase, DNA and phage tails yielded up to 10(7 )viable phages per milliliter of in vitro reaction under optimized conditions. The presence of neutral polymers and polyamines had a concentration and type dependent effect in the packaging reaction. The terminase donor extract lost rapidly activity at 30 degrees C in contrast to the stability of the prohead donor extract. Maturation to infective virions was observed using both procapsids assembled in SPP1 infected cells and procapsid-like structures assembled in Escherichia coli that overexpressed the SPP1 prohead gene clusters. Neither a majority of aberrant capsid-related structures present in the latter material nor procapsids lacking the portal protein inhibited DNA packaging. Addition of purified portal protein reduced DNA packaging activity in vitro only at concentrations 20-fold higher than those found in the SPP1 infected cell. The SPP1 DNA packaged in vitro originated exclusively from the terminase donor extract. This packaging selectivity was not observed in vivo during mixed infections. The data are compatible with a model for processive headful DNA packaging in which terminase and DNA co-produced in the same cell are tightly associated and can effectively discriminate the portal vertex of DNA packaging-proficient proheads from aberrant structures, from portal-less procapsids, and from isolated portal protein.

Shape and DNA packaging activity of bacteriophage SPP1 procapsid: protein components and interactions during assembly

The procapsid of the Bacillus subtilis bacteriophage SPP1 is formed by the major capsid protein gp13, the scaffolding protein gp11, the portal protein gp6, and the accessory protein gp7. The protein stoichiometry suggests a T=7 symmetry for the SPP1 procapsid. Overexpression of SPP1 procapsid proteins in Escherichia coli leads to formation of biologically active procapsids, procapsid-like, and aberrant structures. Co-production of gp11, gp13 and gp6 is essential for assembly of procapsids competent for DNA packaging in vitro. Presence of gp7 in the procapsid increases the yield of viable phages assembled during the reaction in vitro five- to tenfold. Formation of closed procapsid-like structures requires uniquely the presence of the major head protein and the scaffolding protein. The two proteins interact only when co-produced but not when mixed in vitro after separate synthesis. Gp11 controls the polymerization of gp13 into normal (T=7) and small sized (T=4?) procapsids. Predominant formation of T=7 procapsids requires presence of the portal protein. This implies that the portal protein has to be integrated at an initial stage of the capsid assembly process. Its presence, however, does not have a detectable effect on the rate of procapsid assembly during SPP1 infection. A stable interaction between gp6 and the two major procapsid proteins was only detected when the three proteins are co-produced. Efficient incorporation of a single portal protein in the procapsid appears to require a structural context created by gp11 and gp13 early during assembly, rather than strong interactions with any of those proteins. Gp7, which binds directly to gp6 both in vivo and in vitro, is not necessary for incorporation of the portal protein in the procapsid structure.

The distribution of catecholamines between plasma and platelets in cyclosporin A-induced hypertensive rats

One of the most serious side effects of the immunosuppressive agent, cyclosporin A (CsA), is drug-related hypertension. As it is generally accepted, the sympathetic nervous system may play an important role in the development or maintenance of this abnormal pathophysiological situation. This study is aimed at assessing plasma and platelet catecholamines, and a possible connection to cyclosporin A-induced increased arterial blood pressure. It was thus based on an investigation in which Wistar rats were divided into three groups: one taking only orange juice (control) and the other two receiving 5 and 30 mg kg(-1)('trough' and 'peak') of cyclosporin A (Sandimmun Neoral), daily, for 7 weeks. Plasma and platelet noradrenaline, adrenaline and dopamine levels and arterial blood pressures were evaluated before the start of the study (week 0) and after 2, 4 and 7 weeks. Plasma and platelet catecholamines increased drastically in the 'peak' CsA concentration-treated group, which contrasts with the slight decrease observed in the group treated with the 'trough' concentration. However, both groups revealed an increase in blood pressures, when compared with the control group. These findings suggest that at least 'peak' cyclosporin A concentration alters significantly the plasma and platelets catecholamines levels, which may contribute to the cyclosporin A-induced hypertension. Other contributions, regardless of catecholamine content disturbances, might occur, at least at 'trough' CsA concentrations.