Clomethiazole is neuroprotective in models of global and focal cerebral ischemia when infused at doses producing clinically relevant plasma concentrations

We investigated the neuroprotective effect of infusing various doses of clomethiazole in models of global and focal cerebral ischemia. In a model of global ischemia, gerbils were infused with clomethiazole (intravenous), attaining steady state plasma concentrations of between 1 and 13 microM for 24 h. In a transient middle cerebral artery occlusion model in rats, clomethiazole was administered subcutaneously over 22.75 h using osmotic minipumps producing steady state plasma concentrations of between 1 and 13 microM. Clomethiazole was protective in these models at plasma concentrations of respectively 6.1 microM and above and 3.5 microM and above. Clomethiazole is thus neuroprotective in both global and focal ischemia at plasma concentrations known to be well tolerated in stroke patients.

The metabolism of clomethiazole in gerbils and the neuroprotective and sedative activity of the metabolites

A single dose of clomethiazole (600 micromol kg(-1) i.p.) has previously been shown to be neuroprotective in the gerbil model of global ischaemia. In gerbils, clomethiazole (600 micromol kg(-1)) injection produced a rapid appearance (peak within 5 min) of drug in plasma and brain and similar clearance (plasma t(1/2): 40 min) from both tissues. The peak brain concentration (226+/-56 nmol g(-1)) was 40% higher than plasma. One major metabolite, 5-(1-hydroxyethyl-2-chloro)-4-methylthiazole (NLA-715) and two minor metabolites 5-(1-hydroxyethyl)-4-methylthiazole (NLA-272) and 5-acetyl-4-methylthiazole (NLA-511) were detected in plasma and brain. Evidence suggested that clomethiazole is metabolized directly to both NLA-715 and NLA-272. Injection of NLA-715, NLA-272 or NLA-511 (each at 600 micromol kg(-1)) produced brain concentrations respectively 2.2, 38 and 92 times greater than seen after clomethiazole (600 micromol kg(-1)). Clomethiazole (600 micromol kg(-1)) injected 60 min after a 5 min bilateral carotid artery occlusion in gerbils attenuated the ischaemia-induced degeneration of the hippocampus by approximately 70%. The metabolites were not neuroprotective at this dose. In mice, clomethiazole (600 micromol kg(-1)) produced peak plasma and brain concentrations approximately 100% higher than in gerbils, drug concentrations in several brain regions were similar but 35% higher than plasma. Clomethiazole (ED(50): 180 micromol kg(-1)) and NLA-715 (ED(50): 240 micromol kg(-1)) inhibited spontaneous locomotor activity. The other metabolites were not sedative (ED(50) >600 micromol kg(-1)). These data suggest that the neuroprotective action of clomethiazole results from an action of the parent compound and that NLA-715 contributes to the sedative activity of the drug. British Journal of Pharmacology (2000) 129, 95 - 100

Human and behavioral factors contributing to spine-based neurological cockpit injuries in pilots of high-performance aircraft: recommendations for management and prevention

In high-performance aircraft, the need for total environmental awareness coupled with high-g loading (often with abrupt onset) creates a predilection for cervical spine injury while the pilot is performing routine movements within the cockpit. In this study, the prevalence and severity of cervical spine injury are assessed via a modified cross-sectional survey of pilots of multiple aircraft types (T-38 and F-14, F-16, and F/A-18 fighters). Ninety-five surveys were administered, with 58 full responses. Fifty percent of all pilots reported in-flight or immediate post-flight spine-based pain, and 90% of fighter pilots reported at least one event, most commonly (> 90%) occurring during high-g (> 5 g) turns of the aircraft with the head deviated from the anatomical neutral position. Pre-flight stretching was not associated with a statistically significant reduction in neck pain episodes in this evaluation, whereas a regular weight training program in the F/A-18 group approached a significant reduction (mean = 2.492; p < 0.064). Different cockpit ergonomics may vary the predisposition to cervical injury from airframe to airframe. Several strategies for prevention are possible from both an aircraft design and a preventive medicine standpoint. Countermeasure strategies against spine injury in pilots of high-performance aircraft require additional research, so that future aircraft will not be limited by the human in control.

Hydrodynamic radii of native and denatured proteins measured by pulse field gradient NMR techniques

Pulse field gradient NMR methods have been used to determine the effective hydrodynamic radii of a range of native and nonnative protein conformations. From these experimental data, empirical relationships between the measured hydrodynamic radius (R(h)) and the number of residues in the polypeptide chain (N) have been established; for native folded proteins R(h) = 4.75N (0.29)A and for highly denatured states R(h) = 2.21N (0.57)A. Predictions from these equations agree well with experimental data from dynamic light scattering and small-angle X-ray or neutron scattering studies reported in the literature for proteins ranging in size from 58 to 760 amino acid residues. The predicted values of the hydrodynamic radii provide a framework that can be used to analyze the conformational properties of a range of nonnative states of proteins. Several examples are given here to illustrate this approach including data for partially structured molten globule states and for proteins that are unfolded but biologically active under physiological conditions. These reveal evidence for significant coupling between local and global features of the conformational ensembles adopted in such states. In particular, the effective dimensions of the polypeptide chain are found to depend significantly on the level of persistence of regions of secondary structure or features such as hydrophobic clusters within a conformational ensemble.

Characterization of a human melanoma cell line with non-oestrogen receptor dependent tamoxifen resistance

While investigating the mechanism of synergistic cytotoxicity between tamoxifen (TAM) and cisplatin (DDP) we developed a TAM-resistant variant of the human melanoma cell line T-289. We sought to characterize this cell line with respect to the effect of TAM resistance on a variety of different intracellular cell cycle control and apoptotic pathways. A TAM-resistant variant cell line (289 TAMs) was developed and the technique of Western analysis was to determine the changes in protein expression that occurred as a result of the development of TAM resistance. In this model, TAM resistance resulted in an increase in the detectable basal levels of cyclin E, GADD 153, p16, BAX, Bcl-XL, and wild-type and mutant p53, an increase in TAM induction of p16, and a decrease in the detectable basal levels of cyclin D1, p21 and p27. There were no detectable changes in the levels of pRb. In the TAM-resistant variant, p21 levels were essentially undetectable, while p27 was present and maintained its response to TAM Induction, albeit at a much lower level. This investigation demonstrates that the development of TAM resistance is associated with a change in the detectable levels of a variety of cell cycle control and apoptosis-related proteins. While the exact role that each change plays in the development of tamoxifen resistance remains to be determined, these data suggest that the development of resistance to a particular agent results in changes in multiple, seemingly unrelated pathways. These data have implications for future studies in both the laboratory and the clinic.

Efficient refocusing of one-spin and two-spin interactions for NMR quantum computation

The use of spin echoes to refocus one-spin interactions (chemical shifts) and two-spin interactions (spin-spin couplings) plays a central role in both conventional NMR experiments and NMR quantum computation. Here we describe schemes for efficient refocusing of such interactions in both fully and partially coupled spin systems.

Using the GOHAI to assess oral health status of frail homebound elders: reliability, sensitivity, and specificity

A pilot study assessed the clinically determined and self-reported oral health status of 50 randomly selected homebound patients served by Boston's Home Medical Service. The sample was largely female, low-income, and edentulous. The median age of the patients was 81 years (range, 64-101). While 76% deemed themselves to be in good to excellent oral health, 80% of the patients had not seen a dentist within the last two years, and 80% were found to be in need of routine dental care. To assess whether the Geriatric Oral Health Assessment Index (Atchison and Dolan, 1990) could be used by non-dental health professionals to determine the need for requesting dental consultation, the study physician repeated the administration of the GOHAI for 23 of the 50 subjects within eight weeks of the initial examination. For the 23 subjects having both dentist- and physician-administered GOHAI scores, the intraclass correlation coefficient was r = 0.61 (p = 0.002), indicating good agreement between the dentist's and physician's administrations of the GOHAI. However, given the high prevalence of need for care, the GOHAI appears to be of less value than an examination for identifying persons who need dental care in this population. Future research is needed to examine the GOHAI's sensitivity and specificity in populations with low to moderate prevalence of treatment need.

Nerve entrapments of the upper extremity: A surgical perspective

The surgeon's perspective of nerve entrapment lesions in the upper extremity is discussed in this article. The focus is on the most common lesions of the median, ulnar, and radial nerves. An understanding of the anatomy and the potential pathologies provide the basis for surgical treatment. Current treatment protocols are discussed with the authors' recommendations that are based upon experience and literature review.

Oral/pharyngeal, laryngeal, and lung cancer discharge trends in Department of Veterans Affairs hospitals

OBJECTIVE

This paper describes trends in oral and pharyngeal (O/P) cancer diagnoses in Department of Veterans Affairs (VA) hospitals from 1983 to 1993 and compares these trends to those of laryngeal and lung cancers.

METHODS

The VA patient treatment file was used to identify unique hospital discharges from 1983 to 1993 having ICD-9-CM codes for O/P, laryngeal, and lung cancers. Descriptive statistics were tabulated to determine prevalence and distribution. Trends of change over time were analyzed using regression analyses of the percent rate on year.

RESULTS

Between 1983 and 1993 the annual number of O/P cases among users of VA hospitals decreased from 4,983 to 3,298. Despite overall declines in O/P cancer discharges in VA, cancer of the pharynx, tongue, and salivary gland continues to increase. O/P cancer in younger persons also continues to increase in VA. Overall, laryngeal cancers significantly increased, while no significant change was associated with lung cancer.

CONCLUSIONS

VA needs to evaluate the changes in the patterns of O/P cancer to ascertain whether this represents a shift in care from inpatient to outpatient care. VA should seek further information regarding these trends to better plan, implement, and evaluate programs to provide early diagnosis and treatment targeted to veterans.

Space radiation concerns for manned exploration

Spaceflight exposes astronaut crews to natural ionizing radiation. To date, exposures in manned spaceflight have been well below the career limits recommended to NASA by the National Council of Radiation Protection and Measurements (NCRP). This will not be the case for long-duration exploratory class missions. Additionally. International Space Station (ISS) crews will receive higher doses than earlier flight crews. Uncertainties in our understanding of long-term bioeffects, as well as updated analyses of the Hiroshima. Nagasaki and Chernobyl tumorigenesis data, have prompted the NCRP to recommend further reductions by 30-50% for career dose limit guidelines. Intelligent spacecraft design and material selection can provide a shielding strategy capable of maintaining crew exposures within recommended guidelines. Current studies on newer radioprotectant compounds may find combinations of agents which further diminish the risk of radiation-induced bioeffects to the crew.

Counseling youth in tobacco-use prevention: determinants of clinician compliance

OBJECTIVE

The rate and determinants of tobacco prevention and cessation counseling to youth were examined for orthodontists participating in a controlled trial to decrease the incidence of tobacco use among adolescents.

METHODS

A cross-sectional interview design in private practice offices throughout Southern California was used. The survey was completed with 126 (82%) orthodontists. Clinicians randomly assigned to the experimental group (N = 77) received a 1.5 h workshop, anti-tobacco materials, reimbursement for provision of anti-tobacco prescriptions, and quarterly checkup visits. Control group clinicians (N = 77) did not receive training, materials, or visits.

RESULTS

Experimental group clinicians talked to more adolescent nonsmokers about never beginning tobacco use than did control group clinicians (P < 0.05). Experimental group clinicians talked to more adolescent tobacco users than did control group clinicians; however, the difference was not statistically significant. Content and determinants of counseling were affected by participation in the intervention.

CONCLUSIONS

Though training and support increased prevention and cessation counseling, absolute rates remained less than optimal. Social learning factors were associated with prevention and cessation counseling.

Independent nucleation and heterogeneous assembly of structure during folding of equine lysozyme

The refolding of equine lysozyme from guanidinium chloride has been studied using hydrogen exchange pulse labelling in conjunction with NMR spectroscopy and stopped flow optical methods. The stopped flow optical experiments indicate that extensive hydrophobic collapse occurs rapidly after the initiation of refolding. Pulse labelling experiments monitoring nearly 50 sites within the protein have enabled the subsequent formation of native-like structure to be followed in considerable detail. They reveal that an intermediate having persistent structure within three of the four helices of the alpha-domain of the protein is formed for the whole population of molecules within 4 ms. Subsequent to this event, however, the hydrogen exchange protection kinetics are complex and highly heterogeneous. Analysis of the results by fitting to stretched exponential functions shows that a series of other intermediates is formed as a consequence of the stepwise assembly of independently nucleated local regions of structure. In some molecules the next step in folding involves the stabilisation of the remaining helix in the alpha-domain, whilst in others persistent structure begins to form in the beta-domain. The formation of native-like structure throughout the beta-domain is itself heterogeneous, involving at least three kinetically distinguishable steps. Residues in loop regions throughout the protein attain persistent structure more slowly than regions of secondary structure. There is in addition evidence for locally misfolded regions of structure that reorganise on much longer timescales. The results reveal that the native state of the protein is generated by the heterogeneous assembly of a series of locally cooperative regions of structure. This observation has many features in common with the findings of recent theoretical simulations of protein folding.

Effects of hard metal on nitric oxide pathways and airway reactivity to methacholine in rat lungs

To examine whether the development of hard metal (HM)-induced occupational asthma and interstitial lung disease involves alterations in nitric oxide (NO) pathways, we examined the effects of an industrial HM mixture on NO production, interactions between HM and lipopolysaccharide (LPS) on NO pathways, and alterations in airway reactivity to methacholine in rat lungs. HM (2.5 to 5 mg/100 g intratracheal) increased NO synthase (NOS; EC 1.14.23) activity of rat lungs at 24 h without increasing inducible NOS (iNOS) or endothelial NOS (eNOS) mRNA abundance or iNOS, eNOS, or brain NOS (bNOS) proteins. The increase in NOS activity correlated with the appearance histologically of nitrotyrosine immunofluorescence in polymorphonuclear leukocytes (PMN) and macrophages. Intraperitoneal injection of LPS (1 mg/kg) caused up-regulation of iNOS activity, mRNA, and protein at 8 h but not at 24 h. HM at 2.5 mg/100 g, but not at 5 mg/100 g, potentiated the LPS-induced increase in NOS activity, iNOS mRNA, and protein. However, HM decreased eNOS activity at 8 h and eNOS protein at 24 h. Whole body plethysmography on conscious animals revealed that HM caused basal airway obstruction and a marked hyporeactivity to inhaled methacholine by 6-8 h, which intensified over 30-32 h. HM-treatment caused protein leakage into the alveolar space, and edema, fibrin formation, and an increase in the number of inflammatory cells in the lungs and in the bronchoalveolar lavage. These results suggest that a HM-induced increase in NO production by pulmonary inflammatory cells is associated with pulmonary airflow abnormalities in rat lungs.

Endoscopic surgery and telemedicine in microgravity: developing contingency procedures for exploratory class spaceflight

OBJECTIVES

The risk of a urinary calculus during an extended duration mission into the reduced gravity environment of space is significant. For medical operations to develop a comprehensive strategy for the spaceflight stone risk, both preventive countermeasures and contingency management (CM) plans must be included.

METHODS

A feasibility study was conducted to demonstrate the potential CM technique of endoscopic ureteral stenting with ultrasound guidance for the possible in-flight urinary calculus contingency. The procedure employed the International Space Station/Human Research Facility ultrasound unit for guide wire and stent localization, a flexible cystoscope for visual guidance, and banded, biocompatible soft ureteral stents to successfully stent porcine ureters bilaterally in zero gravity (0g).

RESULTS

The study demonstrated that downlinked endoscopic surgical and ultrasound images obtained in 0g are comparable in quality to 1g images, and therefore are useful for diagnostic clinical utility via telemedicine transmission.

CONCLUSIONS

In order to be successful, surgical procedures in 0g require excellent positional stability of the operating surgeon, assistant, and patient, relative to one another. The technological development of medical procedures for long-duration spaceflight contingencies may lead to improved terrestrial patient care methodology and subsequently reduced morbidity.

The ability of non-ergonomists in the health care setting to make manual handling risk assessments and implement changes

The health care setting presents particular risks from manual handling and it is known that training in manual handling techniques is ineffective in reducing these risks when used as a stand-alone measure. The 'Manual Handling Operations Regulations 1992' requires employers to consider hazardous manual handling, advising the use of an ergonomics approach. However, it is not known how well-equipped non-ergonomists in the health care setting are to deal with this approach. Therefore, the ability of non-ergonomists to make manual handling risk assessments, with or without additional training, and to implement changes to the work environment was investigated. Twenty-five pairs of subjects from a broad cross section of departments in a busy teaching hospital were studied; training and a guide book were provided for one of each pair and the guide book only for the other. Subjects then independently prioritised three tasks in their department and undertook a full assessment of a specified task. All work was repeated by an ergonomist and the subjects' assessments were scored in comparison with the ergonomist. Each department was followed up after six months to assess progress with implementing recommendations. Trends in the data indicated that both groups appeared able to identify hazards though not necessarily to prioritise the tasks. The trained group tended to score better in assessments although wide variation existed within both groups and inter-group differences were not significant at the 5% level. Approximately half of staff assessments were considered 'adequate' to 'very good', in comparison with the ergonomist. Implementation of assessment recommendations ranged from nil to almost full compliance. Incomplete implementation seemed to be related to an apparent confusion in some departments over who was responsible for making changes, a lack of finances for changes and overstretched managers having other priorities.

Separate quantification of doubly and singly 13C-labeled metabolites by HSQC-filtered J spectroscopy

NMR detection of multiply labeled compounds in biological samples is often used to follow metabolic pathways. Detection of protons bound to 13C atoms offers a more sensitive approach than direct 13C detection, but generally results in the loss of carbon-carbon coupling information. We have modified an HSQC sequence to refocus the carbon chemical shifts in order to obtain a proton-correlated 13C homonuclear J spectrum, which allows us to measure singly and doubly labeled compounds in the same spectrum.

Effects of regular walking on cardiovascular risk factors and body composition in normoglycemic women and women with type 2 diabetes

OBJECTIVE

To examine the impact of a 12-week walking program on body composition and risk factors for cardiovascular disease in women with type 2 diabetes and in normoglycemic women with first-degree diabetic relatives.

RESEARCH DESIGN AND METHODS

There were 11 postmenopausal women with type 2 diabetes and 20 normoglycemic women of similar age and BMI who were asked to walk 1 h per day on 5 days each week for 12 weeks. Fitness (estimated VO2max) was assessed with a 1.6-km walking test; body composition was measured by dual-energy X-ray absorptiometry; and sex hormone, metabolic, and lipid concentrations were measured in serum.

RESULTS

After 12 weeks, estimated VO2max improved in both groups (P < 0.005). In the diabetic women, BMI and fat content of the upper body and android waist region decreased (P < 0.05). Concentrations of fasting blood glucose (P < 0.05) HbAlc (P < 0.05), total cholesterol (P < 0.005), and LDL cholesterol (P < 0.05) decreased, while HDL cholesterol and sex hormones were unchanged. In contrast, normoglycemic women failed to lose body fat after 12 weeks of exercise in a walking program. However, their HbAlc, total cholesterol, LDL cholesterol, sex hormone-binding globulin, and total testosterone concentrations decreased (P < 0.05). On pooling the data and including diabetes as a categorical grouping variable, stepwise multiple regression analysis indicated that the change in centralized body fat, but not the change in VO2max, was related to change in fasting blood glucose.

CONCLUSIONS

Twelve weeks of walking increased the fitness of diabetic and normoglycemic women. Improvement of fasting blood glucose was related to the loss of centralized body fat rather than to improved fitness.

Structural and dynamical characterization of a biologically active unfolded fibronectin-binding protein from Staphylococcus aureus

A 130-residue fragment (D1-D4) taken from a fibronectin-binding protein of Staphylococcus aureus, which contains four fibronectin-binding repeats and is unfolded but biologically active at neutral pH, has been studied extensively by NMR spectroscopy. Using heteronuclear multidimensional techniques, the conformational properties of D1-D4 have been defined at both a global and a local level. Diffusion studies give an average effective radius of 26.2 +/- 0.1 A, approximately 75% larger than that expected for a globular protein of this size. Analysis of chemical shift, 3JHNalpha coupling constant, and NOE data show that the experimental parameters agree well overall with values measured in short model peptides and with predictions from a statistical model for a random coil. Sequences where specific features give deviations from these predictions for a random coil have however been identified. These arise from clustering of hydrophobic side chains and electrostatic interactions between charged groups. 15N relaxation studies demonstrate that local fluctuations of the chain are the dominant motional process that gives rise to relaxation of the 15N nuclei, with a persistence length of approximately 7-10 residues for the segmental motion. The consequences of the structural and dynamical properties of this unfolded protein for its biological role of binding to fibronectin have been considered. It is found that the regions of the sequence involved in binding have a high propensity for populating extended conformations, a feature that would allow a number of both charged and hydrophobic groups to be presented to fibronectin for highly specific binding.

Quantum logic gates and nuclear magnetic resonance pulse sequences

There has recently been considerable interest in the use of nuclear magnetic resonance (NMR) as a technology for the implementation of small quantum computers. These computers operate by the laws of quantum mechanics, rather than classical mechanics and can be used to implement new quantum algorithms. Here we describe how NMR in principle can be used to implement all the elements required to build quantum computers, and draw comparisons between the pulse sequences involved and those of more conventional NMR experiments.

Hypophosphataemia. Pathophysiology, effects and management on the intensive care unit

Routine detection and treatment of hypophosphataemia on the intensive care unit is commonplace. Hypophosphataemia has been associated with a multitude of clinical effects and there are many associations between correction of hypophosphataemia and improvement in symptoms. However, there is no evidence at present to support the routine correction of hypophosphataemia in the absence of clinical symptoms or signs.

Amyloid fibril formation by an SH3 domain

The SH3 domain is a well characterized small protein module with a simple fold found in many proteins. At acid pH, the SH3 domain (PI3-SH3) of the p85alpha subunit of bovine phosphatidylinositol 3-kinase slowly forms a gel that consists of typical amyloid fibrils as assessed by electron microscopy, a Congo red binding assay, and x-ray fiber diffraction. The soluble form of PI3-SH3 at acid pH (the A state by a variety of techniques) from which fibrils are generated has been characterized. Circular dichroism in the far- and near-UV regions and 1H NMR indicate that the A state is substantially unfolded relative to the native protein at neutral pH. NMR diffusion measurements indicate, however, that the effective hydrodynamic radius of the A state is only 23% higher than that of the native protein and is 20% lower than that of the protein denatured in 3.5 M guanidinium chloride. In addition, the A state binds the hydrophobic dye 1-anilinonaphthalene-8-sulfonic acid, which suggests that SH3 in this state has a partially formed hydrophobic core. These results indicate that the A state is partially folded and support the hypothesis that partially folded states formed in solution are precursors of amyloid deposition. Moreover, that this domain aggregates into amyloid fibrils suggests that the potential for amyloid deposition may be a common property of proteins, and not only of a few proteins associated with disease.

Using oral quality of life measures in geriatric dentistry

OBJECTIVE

The purpose of this paper is to present potential uses of existing oral-specific quality of life (OQOL) instruments in geriatric dentistry.

METHOD

Selected existing OQOL instruments were reviewed. Three examples of how such instruments have or could be used in geriatric dentistry are presented.

CONTENT OF REVIEW

Nine OQOL instruments are briefly reviewed. The potential uses in geriatric dentistry include population applications and uses with individuals for political, theoretical and practical reasons. Practical uses include identification of persons needing treatment, assessing oral health needs in populations and estimating resources required to meet those needs, as endpoints in clinical trials and as measures of the impact of care provided.

CONCLUSIONS

The ultimate value of OQOL measures will be measured by their usefulness in improving care of patients. The development of streamlined instruments and a core instrument which can be used in multiple populations and serve as a baseline to which other measures are added is recommended.