Knee thrust prevalence and normative hip-knee-ankle angle deviation values among healthy individuals across the lifespan.

OBJECTIVE: To report the prevalence of varus thrust and normative values for hip-knee-ankle (HKA) angle deviation across the lifespan, and to explore associations between HKA angle deviation and selected clinical factors. DESIGN: This was a cross-sectional observational study of 572 participants from the 1000 Norms Project, aged 3-101 years and who self-reported as being healthy. Video recordings (2D) of frontal plane gait were reviewed by physiotherapists for presence of knee thrust and quantification of HKA angle deviation (the difference between HKA angle at initial contact and mid-stance). Age and sex-stratified normative HKA angle deviation values were presented as means and 95% confidence intervals (CIs). Correlations were calculated between HKA angle and clinical measures (age, sex, body mass index (BMI), alignment, knee and hip strength, Knee Injury and Osteoarthritis Outcomes Scores (KOOS), foot posture index, temporo-spatial gait, and hypermobility). RESULTS: Overall, 31% of the cohort had varus thrust, most prevalent among adults older than 60 years (42%) and children aged 3-9 (41%). Varus thrust was common in adolescents (25%) and adults aged 20-59 (23%). Mean HKA angle deviation for the entire cohort was 1.2° (95%CI: 1.07, 1.36) towards varus, and 2.1° (95%CI: 1.84, 2.36) among people with clinical varus thrust. Weak associations were identified between HKA angle deviation and BMI, stride width, and KOOS-Sports among adolescents, and in adults weakly associated with height. CONCLUSIONS: Prevalence of varus thrust is common across the lifespan. Normative values established here can be readily used by clinicians and researchers in monitoring this gait deviation.

Self-reported knee pain and disability among healthy individuals: reference data and factors associated with the Knee injury and Osteoarthritis Outcome Score (KOOS) and KOOS-Child.

OBJECTIVE: To develop normative reference data for the Knee injury and Osteoarthritis Outcome Score (KOOS) and KOOS-Child, as well as investigate socio-demographic, psychological and physical factors associated with knee pain and disability among healthy adults. METHOD: The KOOS or KOOS-Child (each containing five subscales) was administered to participants aged 8-101 years within the 1000 Norms Project, an observational study of 1000 self-reported healthy individuals. Self-efficacy, physical activity, body mass index (BMI), lower limb alignment, knee frontal plane projection angle (FPPA), knee range of motion (ROM), knee and hip strength, six-minute walk, 30-second chair stand and timed up and down stairs tests were collected. KOOS data were dichotomised using established cut-off scores and logistic regression analyses were conducted for each subscale. RESULTS: Socio-demographic characteristics were similar to the Australian population. Normative reference data were generated for children (8-17 years) and adults (18-101 years). Female adults were up to twice as likely to report knee pain, symptoms and sport/recreation (Sport/Rec) limitations compared to males (P < .05). Older age, lower self-efficacy, greater BMI, varus lower limb alignment, lower knee flexion ROM and lower hip external rotation (ER) strength were independently associated with knee pain and disability among adults. CONCLUSIONS: Age- and gender-stratified reference data for the KOOS and KOOS-Child have been developed to guide interpretation of results in practice and research for individuals with knee disorders. Psychological and physical factors are linked with self-reported knee pain/disability among adults, and longitudinal studies to investigate causation are required.

Percutaneous absorption of iodochlorhydroxyquin in humans.

Iodochlorhydroxyquin (I) is used in the treatment of diaper rash and other skin disorders, and is presumed to undergo little or no percutaneous absorption. The absorption of (I) from a 3% cream was studied in 5 normal male subjects after a single application of the cream for 12 h. Plasma levels of the drug were followed for 24 h after initial application while urinary excretion was measured for 54 h. (I) was extracted from plasma and urine and assayed by high-performance liquid chromatography. The drug in the range of 0.37-0.56 micrograms/ml was detected in plasma 2 h after application and persisted throughout the treatment period. The mean excretion rate after 12 h of application was 58.4 micrograms/h and the excretion rate was 8.8 micrograms/h at 42 h posttreatment. The elimination rate constant was calculated to be 0.15 h-1. Approximately 40% of the drug was absorbed over the 12-h application period. From the above results it is apparent that significant percutaneous absorption of (I) occurs.

Location of the coagulase gene in Staphylococcus aureus.

Evidence is presented for the chromosomal location of the coagulase determinant in most strains of Staphylococcus aureus. By the use of a pour-plate technique, transduction of the capacity to produce coagulase to a coagulase-negative mutant of S. aureus was studied. The frequencies of transduction were low unless the transducing phage was exposed to ultraviolet irradiation and the recipient was lysogenised with the transducing phage. Attempts to transfer the coagulase gene from S. aureus to S. epidermidis were not successful.

A survey of alcohol and other drug use behaviors and risk factors in health profession students.

This survey assessed the alcohol and other drug (AOD) use habits and risk factors of health profession students at a midwestern university health science center. The authors administered a 75-item survey to 1,707 students in selected classrooms: 984 students responded for a return rate of 57.6%. In 1990, they found, alcohol use among the health profession students in the past year was comparable to that of undergraduate college students nationally (86%), although significantly fewer health profession students drank heavily (27% had five or more drinks in the past 2 weeks, compared with 41% of college students). The percentage of health profession students who reported using tobacco or illicit drugs was lower than the percentage of undergraduate students who used these substances. At the time of the study, 16% of the respondents may have had a potential current alcohol problem and 3.5% a potential drug problem. Pharmacy students most often reported negative consequences from their AOD use. Peer pressure influenced the drinking decisions of 55% of the respondents; students in dentistry and pharmacy experienced the least support from peers for their decisions to abstain from drinking. Family histories of alcohol problems were reported by 38% of the respondents, and family histories of drug use by 14.8%. Male health profession students, when compared with the female professional students, drank more and experienced more consequences of their drinking or drug use and were also more influenced by peers.

Oral syringe use survey.

Use of oral syringes at children's and ASHP-accredited residency hospitals in the United States was surveyed. Questionnaires were mailed to 131 hospitals; 117 (89.3%) were returned. Of the responding hospitals, 54.5% of children's hospitals and 67.1% of residency hospitals used oral syringes. There was no definite preference for a particular brand or type (glass vs. plastic) of syringe. Patients who often required liquid dosage forms, including pediatric and geriatric patients and patients with nasogastric tubes, were most frequently included in oral syringe distribution systems. Twenty-six of the 73 hospitals utilizing oral syringes used them for most unit dose liquids in all drug distribution systems. The remainder reported use for specific medications or circumstances. Expiration dating policies varied from 24 hours to one year to the manufacturer's expiration dating. The survey indicates widespread use of oral syringes and identifies a need for evaluation of medication stability in these devices.

Relatedness of tetracycline resistance plasmids among species of coagulase-negative staphylococci.

Four isolates of Staphylococcus aureus and 98 isolates of coagulase-negative staphylococci representing six species all obtained from endocervical cultures were examined for antimicrobial susceptibility and for the presence of plasmids. More than 80% of the isolates were susceptible to each of 12 antimicrobial agents tested, whereas only 33% were susceptible to penicillin G, 30% were susceptible to cadmium chloride, and 41% were susceptible to tetracycline. Although no species-related susceptibility or plasmid patterns were detected, 77 isolates contained at least one plasmid and 43 contained a plasmid similar in mass to a 2.7-megadalton tetracycline resistance plasmid previously reported in staphylococci. Association of tetracycline resistance with plasmids of this size in four species was determined from curing experiments. No plasmids homologous with the tetracycline resistance locus of the Escherichia coli plasmid pBR322 were found among 11 isolates examined by DNA hybridization. Homology with a 2.7-megadalton plasmids (pRC701) from an endocervical isolate of S. aureus, however, was apparent for 2.7-megadalton plasmids harbored by six isolates as well as with larger plasmids harbored by three isolates. Restriction analysis revealed that pRC701 shared structural identity with two plasmids of a similar mass from two species of coagulase-negative staphylococci as well as with a previously characterized tetracycline resistance plasmid originating in S. aureus.

Comparison of purified alpha-toxins from various strains of Staphylococcus aureus.

Alpha-toxin from five strains of Staphylococcus aureus, including Wood 46, was purified by isoelectric focusing. The alpha-toxins obtained from different strains were similar. The isoelectric point of the purified toxins was 8.65 +/- 0.15. Sharp concentration peaks were not always obtained. In the ultracentrifuge the alpha-toxins migrated usually as three peaks which could be dissociated with propionic acid to yield one peak. A single line of identity was obtained in immunoelectrophoresis when a heterologous antiserum was reacted with the five purified toxins. It was concluded that the widespread use of the Wood 46 strain for the production of alpha-toxin is justified.

Purification and properties of staphylococcal beta hemolysin. II. Purification of beta hemolysin.

Staphylococcal beta hemolysin from the 681 strain of Staphylococcus aureus grown in a Heart Infusion dialysate semisolid medium under 10% carbon dioxide was obtained in an immunoelectrophoretically pure form by a combination of procedures of precipitation with 2 volumes of acetone followed by chromatography on diethylaminoethyl cellulose at pH 6.0. The acetone precipitation procedure did not show any deleterious effect on the hemolytic activity of the beta hemolysin unless the precipitate was left in contact with the acetone for at least 4 hr. The crude preparations contained two types of beta hemolysin. One of these represented the major portion of the total activity of beta hemolysin and behaved as a cation. The other represented a minor (1/5,000) portion of the total beta hemolysin activity and behaved as an anion. These active principles were designated as cationic and anionic beta hemolysins, respectively. An unexpected increase in the total beta hemolysin activity of the crude preparations was noted when these were concentrated by dialysis against polyethylene glycol (20 m). This effect was probably due to polyethylene glycol. A further unexpected increase in the titer of the acetone-precipitated preparations occurred when these were lyophilized. The reason for this incremental increase is not known. It may be due to fragmentation of the beta hemolysin.

Regulation of staphylococcal enterotoxin B: effect of thiamine starvation.

During the transition between the exponential and stationary phases of growth, there was a rapid accumulation of both cell-associated and extracellular enterotoxin B. Extracellular enterotoxin was synthesized until the cells entered the stationary phase during which cell-bound toxin was not detected. The differential rate of toxin synthesis relative to that of total protein synthesis was greater at pH 7.7 than at 6.0. Addition of glucose decreased the differential rate of toxin synthesis. This decrease was greater at pH 7.7 than at 6.0. Addition of pyruvate decreased the differential rate at pH 7.7 but not at 6.0. Analysis of the nongaseous end products of glucose and pyruvate metabolism showed that conditions which favor the oxidative decarboxylation of pyruvate also favor the repression of toxin synthesis. Elimination of thiamine from the medium prevented the oxidative decarboxylation of pyruvate by Staphylococcus aureus S-6 and partially or completely reversed the repression of toxin synthesis by glucose and pyruvate. In the absence of an added energy source, thiamine starvation caused a decrease in protein synthesis but an increased differential rate of toxin synthesis which was greater at pH 7.7 than at 6.0. In the absence of thiamine, pyruvate was not metabolized but caused a decrease in the rate of protein synthesis. This resulted in a twofold increase in the differential rate of toxin synthesis. Thus, conditions which altered the oxidative decarboxylation of pyruvate or decreased the rate of protein synthesis increased the rate of enterotoxin B synthesis.

Loss of the penicillinase plasmid after treatment of Staphylococcus aureus with sodium dodecyl sulfate.

Two strains of Staphylococcus aureus (PC1 and 196E), when grown in medium containing 0.002% sodium dodecyl sulfate (SDS), showed from 96.1 to 100% loss of the ability to produce penicillinase. Resistance to cadmium and zinc was lost concomitantly with the ability to produce penicillinase. A comparison of the rate of curing by SDS with the curing effects exerted by elevated temperature and ethidium bromide suggested that SDS is a more effective plasmid curing agent for susceptible strains of S. aureus than methods in use at present.

Nature of the elimination of the penicillinase plasmid from Staphylococcus aureus by surface-active agents.

Growth of Stapylococcus aureus in various ionic surface-active agents resulted in loss of the ability to produce penicillinase, whereas growth in nonionic surface-active agents had no effect on penicillinase production. The curing effect of various alkyl sulfates was found to be dependent upon the chain length. Curing by surface-active agents could be inhibited by magnesium. Reciprocal transduction experiments showed that curing by a surface-active agent was a property of the plasmid, not of the bacterial strain in which the plasmic resides.

Factors affecting the regulation of staphylococcal enterotoxin B.

Several factors which regulate the synthesis of enterotoxin B were examined in Staphylococcus aureus S-6 and in its heme-requiring mutant S-6H2. The kinetics of enterotoxin B synthesis during anaerobic growth were identical to those observed under aerobic conditions; extracellular enterotoxin accumulated in the medium during the transition between exponential and stationary phase growth. Strain S-6H2 lacked a functional electron transport system unless the medium was supplemented with heme. In a casein hydrolysate medium, the presence or absence of a functional electron transport system had no effect upon the differential rate of toxin synthesis. The repression of toxin synthesis by glucose at either pH 6.0 or 7.7 or by pyruvate at pH 7.7 occurred in the absence of a functional electron transport system, but was enhanced significantly in its presence. Thus, a functional electron transport system appears to be involved in regulating the degree of glucose and pyruvate repression of enterotoxin B synthesis.

Penicillin and tetracycline resistance plasmids in Staphylococcus epidermidis.

The genetic nature of penicillin (Pc) and tetracycline (Tc) resistance plasmids in Staphylococcus epidermidis were studied and compared with those in S. aureus. Of 10 S. epidermidis strains transduced for penicillin resistance, we could isolate Pc plasmids from only 3. One of these plasmids also encoded for cadmium resistance and another encoded for resistance to ethidium bromide, traits also associated with S. aureus Pc plasmids. Endonuclease fingerprinting of the Pc plasmids from the two species revealed extensive heterogeneity. Two S. epidermidis strains were also transduced for tetracycline resistance. Both harbored plasmids indistinguishable from S. aureus Tc plasmids as judged by endonuclease fingerprinting. These data suggest that genetic exchange between S. aureus and S. epidermidis occurs in vivo.