An electron microscope study of the interaction between fructose diphosphate aldolase and actin-containing filaments.

The interaction of fructose diphosphate aldolase with F-actin, F-actin-tropomyosin, and F-actin-tropomyosin-troponin has been studied by using negative staining. In the absence of troponin, minor aggregates of aldolase and the F-actin filaments are formed. A well-ordered lattice structure is only formed in the case of the fully reconstituted filament when the filament-to-filament spacing is 18nm, and the cross-bridge spacing is 38.7 nm. Evidence is presented that the lattice is due to an interaction between troponin and aldolase. The minimum subunit structure of troponin, still capable of giving rise to a lattice, is the troponin-IT complex, which indicates that troponin-C is not involved in aldolase binding.

The adoption of smoke-free hospital campuses in the United States.

BACKGROUND: The adoption of a smoke-free hospital campus policy is often a highly publicised local event. National media coverage suggests that the trend towards adopting these policies is growing, and this publicity can frequently lead hospital administrators to consider the adoption of such policies within their own institutions. Little is actually known, however, about the prevalence of these policies or their impact. OBJECTIVES: To determine the national prevalence of smoke-free hospital campus policies and the relation between these policies and performance on nationally standardised measures for smoking cessation counselling in US hospitals. METHODS: 4494 Joint Commission-accredited hospitals were invited to complete a web-based questionnaire assessing current smoking policies and future plans. Smoking cessation counselling rates were assessed through nationally standardised measures. RESULTS: The 1916 hospitals responding to the survey (43%) were statistically similar to non-responders with respect to performance measure rates, smoking policies and demographic characteristics. Approximately 45% of responders reported an existing smoke-free hospital campus policy. With respect to demographics, higher proportions of smoke-free campus policies were reported in non-teaching and non-profit hospitals. Smoke-free campus hospitals were also more likely to provide smoking cessation counselling to patients with acute myocardial infarction, heart failure and pneumonia who smoke (p<0.001). CONCLUSIONS: By February 2008, 45% of US hospitals (up from approximately 3% in 1992) had adopted a smoke-free campus policy; another 15% reported actively pursuing the adoption of such a policy. By the end of 2009, it is likely that the majority of US hospitals will have a smoke-free campus.

A common theme in the amino acid sequences of actin and many actin-binding proteins?

The amino acid sequences of several actin regulatory proteins have recently been determined. Do these proteins function by mimicking actin-actin interaction sites?

2019 Chitranjan S. Ranawat Award: Elective joint arthroplasty outcomes improve in malnourished patients with nutritional intervention: a prospective population analysis demonstrates a modifiable risk factor.

AIMS: To date, no study has demonstrated an improvement in postoperative outcomes following elective joint arthroplasty with a focus on nutritional intervention for patients with preoperative hypoalbuminaemia. In this prospective study, we evaluated differences in the hospital length of stay (LOS), rate of re-admission, and total patient charges for a malnourished patient study population who received a specific nutrition protocol before surgery. PATIENTS AND METHODS: An analytical report was extracted from the electronic medical record (EMR; Epic, Verona, Wisconsin) of a five-hospital network joint arthroplasty patient data set between 2014 and 2017. A total of 4733 patients underwent joint arthroplasty and had preoperative measurement of albumin levels: 2220 at four hospitals and 2513 at the study hospital. Albumin ≤ 3.4 g/l, designated as malnutrition, was found in 543 patients (11.5%). A nutritional intervention programme focusing on a high-protein, anti-inflammatory diet was initiated in January 2017 at one study hospital. Hospital LOS, re-admission rate, and 90-day charges were compared for differential change between patients in study and control hospitals for all elective hip and knee arthroplasty patients, and for malnourished patients over time as the nutrition intervention was implemented. RESULTS: Malnourished patients with nutritional intervention at the study hospital had shorter hospital LOS beginning in 2017 than malnourished patients at control hospitals during the same period (p = 0.04). Similarly, this cohort had significantly lower primary hospitalization charges, charges associated with hospital re-admissions, and 90-day total charges (p < 0.001). Inclusion of covariant potential confounders (age, anaemia, diabetes, and obesity) did not alter the conclusions of the primary statistical analysis. CONCLUSION: Joint arthroplasty outcomes were positively affected in study patients with low albumin when a high-protein, anti-inflammatory diet was encouraged. Elective surgery was neither cancelled nor delayed with a malnutrition designation. While the entire network population experienced improved postoperative outcomes, malnourished control patients did not experience this improvement. This study demonstrated that education on malnutrition can benefit patients. Cite this article: Bone Joint J 2019;101-B(7 Supple C):17-21.

Hip axis length variation: its correlation with anthropometric measurements in women from three ethnic groups.

UNLABELLED: We compared hip axis length (HAL) in 157 non-Hispanic white women, 292 African-American women, and 210 Mexican-American women. After adjusting for maximal hip girth, there were no residual differences in HAL by ethnicity. Differences in hip fracture risk seen between these groups cannot be explained by ethnic differences in HAL. INTRODUCTION: Hip axis length (HAL) has been reported to be an independent predictor of hip fracture. Significant ethnic differences in HAL have been noted, but no direct comparison has been made between African-American, Mexican-American, and non-Hispanic white women using the same protocol. METHODS: We compared 157 non-Hispanic white women from the Rancho Bernardo Study, 292 women from the Health Assessment Study of African-American Women, and 210 women from the Skeletal Health of Mexican-American Women Project. A standardized questionnaire was used to obtain medical history; height, weight, waist girth, and hip girth were measured; and percentage body fat and HAL were obtained using dual energy X-ray absorptiometry. All HAL comparisons were adjusted for maximum hip girth to control for differences in size magnification by fan-beam absorptiometry. RESULTS: Though there were ethnic differences in the unadjusted HAL measurement, after adjusting for hip circumference, there were no residual differences in HAL with regard to ethnicity: 10.7 cm in Mexican-American women vs. 10.8 in non-Hispanic white women and African-American women (p = 0.61). CONCLUSIONS: There were no ethnic differences in HAL in women from the three ethnic groups. Differences in fracture risk among these groups cannot be explained by ethnic differences in HAL.

Pulsed static magnetic field effects on in-vitro pineal indoleamine metabolism.

In-vitro rat pineal glands stimulated with the beta-adrenergic receptor agonist isoproterenol to induce melatonin synthesis and exposed for 1 h to a pulsed 0.4-G static magnetic field demonstrated significant inhibition of serotonin-N-acetyltransferase activity and melatonin content. 2-h exposure to pulsed magnetic field also resulted in a significant reduction in isoproterenol-induced serotonin-N-acetyltransferase activity. These results support the idea that the cultured pineal gland can be affected directly by artificially generated weak magnetic fields.

The reversible binding of glycolytic enzymes in ovine skeletal muscle in response to tetanic stimulation.

The extent of binding of glycolytic enzymes to the particulate fraction of homogenates was measured in sheep hind muscles after electrical stimulation. As compared to the control muscles, stimulation led to significant increases in the amount of phosphofructokinase, aldolase and glyceraldehyde-3-phosphate dehydrogenase bound to the particulate fraction. The binding of other glycolytic enzymes was not significantly altered. A servey of different hind limb muscles at variable rates of stimulation revealed that each muscle exhibited its own characteristic response pattern in terms of the level of increased enzyme binding. Generally, an increased stimulation rate led to greater enzyme adsorption. The increase in enzyme binding was rapidly reversible for it was shown that the amount of enzyme bound quickly returned to control values when the muscles were allowed to recover in the live anaesthetised animal following cessation of stimulation. Those muscles which exhibited increased enzyme binding were characterised by a marked loss of glycogen and accumulation of lactate suggesting that accelerated glycolytic flux was a necessary condition for the observation of increased enzyme binding. In support of this, enzyme adsorption was observed to the greatest on stimulation of ischemic muscles, whereas in trained muscles, or muscles with depleted glycogen stores induced by prior adrenalin treatment, the increased enzyme binding response was greatly diminished. It is concluded that the variable binding of key glycolytic enzymes has a role to play in the regulation of glycolytic behaviour in skeletal muscle.

Thyroid hormone use and bone mineral density in elderly men.

BACKGROUND: Excessive thyroid hormone use reduces bone density in women. Thyroid hormone use is much less common in men, who also have less osteoporosis. We examined bone mineral density in a community-based sample of elderly men who reported long-term thyroid hormone use. METHODS: All 685 white men aged 50 to 98 years from a Southern California community who participated in a study of osteoporosis were examined. Medication use was validated. Height and weight were measured. Bone mineral density was measured at the ultradistal radius and midshaft radius using single photon absorptiometry and at the hip and lumbar spine using dual energy x-ray absorptiometry. RESULTS: Thirty-three men taking a mean thyroxine-equivalent dose of 130 micrograms daily for an average of 15.5 years were compared with 653 nonusers. There were no significant differences in bone density at any site between users and nonusers, before or after controlling for age, body mass index, smoking, thiazide diuretics, and oral corticosteroid use. Bone density also did not differ according to thyroid hormone type, duration of use, or use of suppressive dose adjusted for body weight. CONCLUSIONS: Long-term thyroid hormone use was not associated with adverse effects on bone mineral density in men.

Status of antithrombotic therapy for patients with atrial fibrillation in university hospitals.

BACKGROUND: The risk of stroke in patients with atrial fibrillation can be significantly reduced with antithrombotic therapy. Despite this, many physicians remain hesitant to prescribe warfarin sodium or aspirin therapy for patients with atrial fibrillation. OBJECTIVE: To assess the use of antithrombotic therapy in patients with atrial fibrillation at 6 academic hospitals in the United States. METHODS: Records were reviewed from consecutive hospital admissions of 309 patients with atrial fibrillation at 6 members of the University Health System Consortium, Oak Brook, III, which is a member driven alliance of 70 academic health centers in the United States. Risk factors for stroke, contraindications to anticoagulant therapy, and use of antithrombotic therapy at admission and discharge were recorded. RESULTS: The mean age of patients was 71.6 years, 54% had chronic, 22% paroxysmal, and 24% new-onset atrial fibrillation. Eighty-two percent of the patients had cardiovascular risk factors that have been associated with increased risk of stroke. At least 1 relative contraindication to anticoagulant therapy was present in 44%. At the time of admission. 32% of the patients with previously diagnosed atrial fibrillation (n = 235) were receiving warfarin (or warfarin plus aspirin), 31% were receiving aspirin alone, and 36% were receiving no antithrombotic therapy. At discharge (n = 230), 41% of these patients were taking warfarin (or warfarin plus aspirin) and 36% were taking aspirin. Forty-four percent of the patients with risk factors for stroke and no contraindications to anticoagulation (n = 134) were discharged on a regimen of warfarin (or warfarin plus aspirin), 34% were discharged on a regimen of aspirin, and 22% received no antithrombotic therapy. CONCLUSIONS: About half of the patients with atrial fibrillation admitted to these academic hospitals had clinical risk factors that are associated with increased risk of stroke and no contraindications to anticoagulation. Antithrombotic therapy was underused in these patients.

Nonsteroidal anti-inflammatory drugs and bone mineral density in older women: the Rancho Bernardo study.

Nonsteroidal anti-inflammatory drugs (NSAIDs) are known to inhibit synthesis of prostaglandins and may help prevent bone loss, but no study has shown the differential association of type or dose of NSAID compound with bone mineral density (BMD). The purpose of this study was to determine the relation of NSAIDs by type and dose to BMD. Participants were 932 Caucasian, community-dwelling women aged 44-98 years from southern California. Data were collected from 1988 to 1991 through the use of standardized medical questionnaires. Medication use was validated by a nurse. BMD at the ultradistal and midshaft radii were measured using single-photon absorptiometry, and at the hip and lumbar spine using dual-energy X-ray absorptiometry. Women (mean age, 72 years) were classified into 818 nonusers and 114 regular daily users of NSAIDs, of which 84 used propionic acid NSAIDs and the remainder used acetic acid NSAIDs. Occasional NSAID users were excluded. Women who used propionic acid NSAIDs, but not acetic acid NSAIDs, had higher BMD at all five sites and significantly higher BMD at the midshaft radius and lumbar spine. These differences remained after controlling for known covariates of osteoporosis. When women with self-reported osteoarthritis were excluded from the model, significantly higher BMD in propionic acid NSAID users was also observed at the femoral neck and total hip. Those who concurrently used estrogen and propionic acid NSAIDs had the highest BMD at all sites, suggesting an additive effect. We conclude that regular daily use of propionic acid NSAIDs, with or without simultaneous use of estrogen, may be helpful in preventing bone loss in older women. However, further research is needed to confirm these results before any clinical practice guidelines can be recommended due to the increased risk of serious complications associated with NSAID use.

Vitamin C supplement use and bone mineral density in postmenopausal women.

Vitamin C is known to stimulate procollagen, enhance collagen synthesis, and stimulate alkaline phosphatase activity, a marker for osteoblast formation. Studies of dietary vitamin C intake and the relation with bone mineral density (BMD) have been conflicting, probably because of the well-known limitations of dietary nutrient assessment questionnaires. The purpose of this study was to evaluate the independent relation of daily vitamin C supplement use with BMD in a population-based sample of postmenopausal women. Subjects were 994 women from a community-based cohort of whom 277 women were regular vitamin C supplement users. Vitamin C supplement use was validated. Daily vitamin C supplement intake ranged from 100 to 5,000 mg; the mean daily dose was 745 mg. Average duration of use was 12.4 years; 85% had taken vitamin C supplements for more than 3 years. BMD levels were measured at the ultradistal and midshaft radii, hip, and lumbar spine. After adjusting for age, body mass index (BMI), and total calcium intake, vitamin C users had BMD levels approximately 3% higher at the midshaft radius, femoral neck, and total hip (p < 0.05). In a fully adjusted model, significant differences remained at the femoral neck (p < 0.02) and marginal significance was observed at the total hip (p < 0.06). Women taking both estrogen and vitamin C had significantly higher BMD levels at all sites. Among current estrogen users, those also taking vitamin C had higher BMD levels at all sites, with marginal significance achieved at the ultradistal radius (p < 0.07), femoral neck (p < 0.07), and total hip (p < 0.09). Women who took vitamin C plus calcium and estrogen had the highest BMD at the femoral neck (p = 0.001), total hip (p = 0.05), ultradistal radius (p = 0.02), and lumbar spine. Vitamin C supplement use appears to have a beneficial effect on levels of BMD, especially among postmenopausal women using concurrent estrogen therapy and calcium supplements.

Thiazide-associated metabolic abnormalities and estrogen replacement therapy: an epidemiological analysis of postmenopausal women in Rancho Bernardo, California.

The objective of this study was to identify abnormalities in lipid and carbohydrate metabolism in women taking thiazide diuretics and determine whether these abnormalities are mitigated by concurrent postmenopausal estrogen replacement therapy. The study design was cross-sectional; its setting was Rancho Bernardo, an upper middle-class community in southern California. The subjects included 1047 white nondiabetic postmenopausal women, aged 50-89 yr, categorized by the use of thiazide diuretic, estrogen replacement therapy, both, or neither. Medical history including behavior, verified medication use, height, weight, fasting chemistry and lipid panels, and a standardized oral glucose tolerance test with fasting and 2-h plasma glucose and serum insulin levels were determined. Compared with nonusers, women taking thiazides had significantly lower high density lipoprotein cholesterol levels and significantly higher fasting triglyceride, glucose, and insulin levels. Concomitant use of thiazide and estrogen yielded lipid profiles and fasting glucose and insulin levels similar to those of subjects receiving estrogen alone, i.e. elevated high density lipoproteins, decreased low density lipoproteins, and lower levels of fasting glucose and insulin compared with those in nonusers. However, thiazide-associated postchallenge glucose and insulin elevations were not modified by estrogen. These patterns were not explained by differences in age, body mass index, exercise, smoking, alcohol use, type or dose of thiazide diuretic, type of estrogen replacement, or serum potassium levels. We conclude that postmenopausal estrogen use masks thiazide-associated dyslipidemia and fasting elevations in glucose and insulin levels, but does not improve thiazide-associated postchallenge glucose intolerance and hyperinsulinemia. Modification of most of the untoward metabolic effects of thiazides in women taking postmenopausal estrogen could provide a new incentive for the use of this traditional antihypertensive in elderly women.

Clinical characteristics and management of acute stroke in patients with atrial fibrillation admitted to US university hospitals.

UNLABELLED: The optimal evaluation and management of patients with atrial fibrillation who suffer an acute ischemic stroke remains controversial. METHODS: Medical records of 171 consecutive patients with atrial fibrillation and acute stroke at six U.S. university hospitals were reviewed. Data collected included the use of antithrombotic therapy, brain and cardiac imaging, bleeding complications, stroke risk factors, and contraindications to anticoagulation. RESULTS: Mean age was 75.4 years. Cardiovascular risk factors associated with increased stroke risk were present in 87%; 35% had at least one contraindication to anticoagulation. Half of the patients with stroke risk factors and no contraindications to anticoagulation were not receiving any antithrombotic therapy at the time of admission. Of the 22 patients who were treated with warfarin, and had INR values on admission, 16 had levels of < 2.0; only six had INR values between 2.0 and 3.0. Transthoracic echocardiography was performed in 107 patients (63%); intracardiac thrombi were visualized in only 5%. Initial brain imaging revealed hemorrhagic transformation in nine. Heparin was used in 93 patients (54%), usually within 48 hours of stroke onset. Patients who received delayed heparin typically did not have repeat brain imaging prior to starting heparin. One patient had a delayed symptomatic cerebral hemorrhage. Of the survivors, 47% were discharged and treated with warfarin (or warfarin plus aspirin), 28% with ASA, 7% with other antithrombotic therapies, and 18% with no antithrombotic therapy. CONCLUSION: Antithrombotic therapy was underutilized and inadequately monitored in atrial fibrillation patients prior to stroke onset. After hospital admission, a wide range of diagnostic and management strategies, which often did not follow current recommendations, were employed.

Pharmacokinetics of twelve anticonvulsant drugs in the rat.

The pharmacokinetic data for 12 anticonvulsant drugs was evaluated after administration to laboratory rats. In all cases the half-life and elimination rate constants were significantly different from clinically-determinant values which suggests that pharmacokinetic parameters should be treated as species specific.

Methoxyindole production by the pineal gland appears to be dependent on the concentration of hydroxy precursors and their affinity for hydroxyindole-O-methyltransferase.

Various pineal gland indole metabolites were separated by thin-layer chromatography after organ culture with tritiated serotonin. The amounts of methoxyindoles produced were remarkably constant and female rats in oestrus appeared to produce greater amounts than male rats. The results show a correlation between methylation and the concentration and affinity of the various hydroxyindoles for hydroxyindole-O-methyltransferase.

Hydroxyindole-O-methyltransferase catalyses production of methoxyindoles in rat pineal gland dependent on the concentration of hydroxy precursors and their affinity for the enzyme.

Indole metabolites were separated by thin-layer chromatography following organ culture of rat pineal glands with tritiated tryptophan. Methoxyindole production was shown to differ substantially from results obtained when pineal glands were incubated with radiolabelled serotonin. The correlation between hydroxy- and corresponding methoxyindoles was, however, remarkably similar to previous results, and indicated that in the pineal gland, it is probable that production of methoxyindoles is dependent on the concentration of the various hydroxyindoles and their relative affinities for hydroxyindole-O-methyltransferase. It is also probable that although several forms of the enzyme may exist in the pineal gland, the catalytic sites are homogeneous in their activity.

Effect of derivatization of the bioavailability of ophthalmic steroids. Development of an in vitro method of evaluation.

An in vitro method for evaluating efficacy of ophthalmic steroid preparations was developed using bovine eyes. The method was tested using three derivatives of dexamethasone (alcohol, acetate, and sodium phosphate) and the results obtained were similar to those obtained in studies using live rabbits, although differences were noted. Bioavailability of the acetate was greatest; that of the sodium phosphate was the lowest. On the basis of this study, bovine eyes could be used as an alternative method for assessing ophthalmic steroid efficacy.

Utilization of transferrin-bound iron by Haemophilus species of human and porcine origins.

Haemophilus influenzae and H. haemolyticus acquired iron bound to human transferrin but not to human lactoferrin, ovo- or porcine transferrins. Conversely the swine pathogens H. pleuropneumoniae and H. parasuis used iron bound only to porcine transferrin. Growth under conditions of iron deprivation induced the production of siderophores and iron-repressible outer membrane proteins in H. parainfluenzae, H. paraphrophilus and H. parasuis but not in H. influenzae, H. haemolyticus or H. pleuropneumoniae. The latter 3 Haemophilus species appear to sequester transferrin bound iron via a siderophore-independent mechanism. However, the ability to produce iron chelating compounds did not enable H. parainfluenzae or H. paraphrophilus to utilize transferrin bound iron.

Distribution of a family of Haemophilus influenzae genes containing CCAA nucleotide repeating units.

A family of genes containing lengths of CCAA nucleotide repeating units directly following the sequence encoding the leader peptide has been identified in Haemophilus influenzae. The length of the CCAA repeats ranges from 6 to 43 and all of the identified genes encode proteins or predicted proteins with a significant homology to bacterial iron- or heme-related outer membrane proteins. We have previously shown that two of these gene products, HgpA and HgpB, bind hemoglobin and the hemoglobin-haptoglobin complex. Studies were performed to define the species distribution of the five identified genes and the CCAA repeats. We show that both the CCAA motif and the structural genes for hemoglobin and hemoglobin-haptoglobin binding are widely distributed among H. influenzae strains.

Construction of antibiotic resistance cassettes with multiple paired restriction sites for insertional mutagenesis of Haemophilus influenzae.

Insertional mutagenesis of cloned genes coupled with site specific recombination into the genome of the parent organism is an ideal method for characterizing gene function. In this paper we describe the production and utility of two antibiotic resistance cassettes for use in Haemophilus influenzae. The mutagenic elements encode resistance to chloramphenicol or spectinomycin. Multiple paired restriction enzyme sites bound both cassettes. Use of these constructs to create mutants in H. influenzae demonstrated that the cassettes are readily incorporated into the genome in single copy and allow easy detection of mutant constructs. The insertions are stable following repeated in vitro passage. In addition, the elements are compatible with each other and allow the construction of multiple mutations within a single strain.