Medical use of cannabis: an addiction medicine perspective.

The use of cannabis for medical purposes, evident throughout history, has become a topic of increasing interest. Yet on the present medical evidence, cannabis-based treatments will only be appropriate for a small number of people in specific circumstances. Experience with cannabis as a recreational drug, and with use of psychoactive drugs that are prescribed and abused, should inform harm reduction in the context of medical cannabis.

Chemical surface modification of lithium disilicate needles of a silica-based ceramic after HF-etching and ultrasonic bath cleaning: Impact on the chemical bonding with silane.

OBJECTIVE: Recommendations to obtain the best bonding to silica-based ceramics are to prepare its surface by hydrofluoric-acid HF etching and regular application of a silane. This study investigated how the HF-etching following by ultrasonic water bath cleaning (recommended protocol to improve the bonding with a composite resin), modifies the surface chemistry of a lithium disilicate glass-ceramic and impacts the chemical bonding with silane. METHODS: Lithium disilicate glass-ceramic discs (IPS Emax Press, Ivoclar Vivadent) were mirror polished, etched with 9% HF for 20 s and rinsed 1 min under water. Two post-etching cleaning were compared: (1) no additional cleaning and (2) immersion in water ultrasonic bath for 4 min. Morphology evolution of the surfaces was carried out by scanning electron microscopy. Chemical changes were studied using X-ray Photoelectron Spectroscopy and Nano Auger Electron Spectroscopy analyses. Identification of the compounds formed with fluorine was based on by High Resolution Transmission Tlectronic Microscopy . RESULTS: Residues left on the surface of the discs after etching, the fluorine salts, were eliminated after the ultrasonic bath cleaning. However, analyses showed presence of fluorine on the lithium disilicate needles associated among others with the lithium. HR-TEM validates the presence of Li2SiF6 crystallized phased. A mechanism to explain silane bonding when Li2SiF6 phase is formed on the Li2Si2O5 needles, is proposed. SIGNIFICANCE: HF-etching leads to the formation of lithium and fluorine contain LiSi2F6 nano-precipitates on the Li2Si2O5 needles which helps to improve the bonding with silane.

Can you shrinkwrap a cow? Protections available for the intellectual property of the animal breeding industry.

There are currently four main intellectual property protection statutory schemes available: copyright, trade secret, trademark and patent. Each of these protects a different aspect of intellectual property, which leaves gaps of protection when an innovation does not fit squarely within the boundaries of the statutes. Contracts allow the industry to tailor the protection desired. One very common approach is to license the product via contract. Licences allow intellectual property owners to retain ownership and give permission to others to use the product. Although there are several types of licences, the most common is the field of use licence, which limits the licensee's use of the product. This often leads to price discrimination where various levels of restriction are offered at corresponding prices. The more rights retained by the owner, the more restricted the buyer is and the lower the purchase price allowing customers to choose the level of restriction they are willing to accept. Therefore, the different uses and needs of various customers can be accounted for and reflected in the price. The animal breeding industry is currently struggling to protect their innovations falling into these statutory gaps. The protection for animal breeding industry innovations is most likely through contract law rather than traditional intellectual property law. By taking advantage of the unique nature of contracts, industry will be able to tailor protection and pricing to best suit the variety of customers and uses for the products sold.

The effects of dexamphetamine on simulated driving performance.

RATIONALE: The number of road fatalities related to the presence of amphetamines in drivers has been relatively constant over the past 10 years. However, there remains uncertainty as to the extent that these drugs induce driving impairment, and whether any such impairments translate to an increase in road fatalities. OBJECTIVES: To examine the acute effects of 0.42 mg/kg dexamphetamine on simulated driving performance, and to establish which, if any, simulated driving abilities become impaired following dexamphetamine administration. METHODS: A repeated-measures, counter-balanced, double-blind, placebo-controlled design was employed. Twenty healthy volunteers completed two treatment conditions-0.42 mg/kg dexamphetamine and placebo. Performance was assessed using a driving simulator task. Blood and saliva samples were obtained prior to the driving tasks and immediately after task completion (120 min and 170 min post-drug administration, respectively). RESULTS: Mean dexamphetamine blood concentrations were 83 ng/ml and 98 ng/ml at 120 min and 170 min, respectively. Results indicated a decrease in overall simulated driving ability following dexamphetamine administration during the day-time but not the night-time scenario tasks. Contributing to this performance reduction, "incorrect signalling", "failing to stop at a red traffic light" and "slow reaction times" were the behaviours most strongly affected by dexamphetamine. CONCLUSIONS: The decrease in simulated driving ability observed during the day-time driving tasks are consistent with the perceptual narrowing or tunnel vision that is associated with dexamphetamine consumption.

Puerperal infection due to group A beta hemolytic streptococcus.

A cluster of 5 patients with puerperal infection due to group A beta hemolytic streptococcus (GABHS) is described. The most striking clinical signs included the early onset of uterine tenderness followed by an abrupt temperature elevation to greater than or equal to 102 F. At the time of uterine tenderness (Day 2, postpartum), 4 of 5 patients had gram-stained lochial smears showing a predominance of gram-positive cocci. The cluster of cases occurred with no source of the infection identified after 365 culture attempts. Therapy was rapidly successful with intravenous penicillin.

Virilization associated with bilateral luteomas of pregnancy.

A case of maternal virilization associated with bilateral luteomas of pregnancy is described. Urinary 17-ketosteroids and plasma testosterone fell from markedly abnormal values to normal limits within 2 weeks of delivery. However, symptoms of virilization persisted in the postpartum state. A possible relation between polycystic ovarian syndrome in the nonpregnant state and luteoma of pregnancy is proposed.

Kinematic properties of voluntary postural sway in patients with unilateral primary hemispheric lesions.

The temporal and spatial characteristics of rapid voluntary body sway following unilateral cerebrovascular accident were assessed in single and combined planes of motion during a visually cued non-choice reaction time movement. Three distinct directions of intentional body sway were assessed: forward, toward the paretic, and toward the non-paretic lower extremity. Fluctuations in the center of foot pressure served as the basis for calculating body displacement and velocity by combining frontal and sagittal movement in an X-Y coordinate system (a bi-planar analysis). A linear regression analysis was used on individual force output channels to reduce the sway motion into separate component parts. The velocity profile in each direction of intended sway was calculated from the slope of the regression line (a single-plane analysis). Bi-planar velocity analysis showed that hemiplegics swayed as fast as normal subjects in any sway direction. In contrast, single plane analysis revealed a decrease in the velocity of hemiplegic sway when weight shifts were directed toward the paretic extremity. Response velocity in the non-paretic direction was similar to a comparison group of normal individuals. The apparent contradiction between single and bi-planar analyses was attributed to hemiplegic sway in extraneous planes of motion surrounding the intended sway path. During the course of body sway, hemiplegics showed a statistically larger range of extraneous movement away from the plane of intended movement. The directional deficits in sway velocity and excursion are compared to previously reported sway pathology associated with lesions of the human central nervous system.

Effects of alcohol and other drugs on driver performance.

In the past century we have learned that driving performance is impaired by alcohol even in low dosage, and that many other drugs are also linked to impairment. This paper is a summary of some of the more relevant studies in the past fifty years--an overview of our knowledge and unanswered questions. There is no evidence of a threshold blood alcohol (BAC) below which impairment does not occur, and there is no defined category of drivers who will not be impaired by alcohol. Alcohol increases not only the probability of collision, but also the probability of poor clinical outcome for injuries sustained when impaired by alcohol. This review samples the results of the myriad studies that have been performed during the last half century as experiments have moved from examination of simple sensory, perceptual and motor behaviours to more complex measures of cognitive functioning such as divided attention and mental workload. These more sophisticated studies show that significant impairment occurs at very low BACs (< 0.02 gm/100 ml). However, much remains to be determined regarding the more emotional aspects of behaviour, such as judgment, aggression and risk taking. Considering that the majority of alcohol related accidents occur at night, there is a need for increased examination on the role of fatigue, circadian cycles and sleep loss. The study of the effects of drugs other than alcohol is more complex because of the number of substances of potential interest, the difficulties estimating drug levels and the complexity of the drug/subject interactions. The drugs of current concern are marijuana, the benzodiazepines, other psychoactive medications, the stimulants and the narcotics. No one test or group of tests currently meets the need for detecting and documenting impairment, either in the laboratory or at the roadside.

Hemophilus influenza septicemia and midtrimester abortion.

A case of midtrimester septic abortion due to Hemophilus influenza is discussed on the basis that the pathogeneses of the septic abortion was due to the hematogenous spread of the organism orginating from upper respiratory infection. The absence of ruptured membranes and the elevated antibody titer at the onset of the pelvic infection were in keeping with this hypothesis. Additional data on the bacteriology of this organism and the probability of the occurrence of a type b organism with original ampicillin resistance are presented.

Lichen sclerosus, genital trauma and child sexual abuse.

OBJECTIVE: To describe the clinical features of lichen sclerosus affecting the genitalia of three unrelated prepubertal girls in whom concerns of sexual abuse had been raised. CLINICAL FEATURES: three girls ranging from 4 to 9 years of age presented with similar genital and anal findings. Their labial skin was atrophic with pale opalescent patches and a variable amount of labial bruising, haemorrhagic blistering and bleeding. In two, the perianal skin was involved in a similar fashion. In each case the hymen was normal with no sign of acute or chronic trauma. CONCLUSIONS: Lichen sclerosus affecting the genitalia of prepubertal females is an uncommon condition that may be mistaken for trauma associated with sexual abuse. An awareness of its clinical features is essential not only for those doctors who examine children for physical signs of sexual abuse but also for primary care doctors who may be confronted with an apparently abused child. Early recognition of this disease should, in the absence of other concerns, prevent unnecessary intervention by police and child protection workers.

Spatial variability in airborne pollen concentrations.

Tests were conducted to determine the relationship between airborne pollen concentrations and distance. Simultaneous samples were taken in 171 tests with sets of eight rotoslide samplers spaced from one to 486 M. apart in straight lines. Use of all possible pairs gave 28 separation distances. Tests were conducted over a 2-year period in urban and rural locations distant from major pollen sources during both tree and ragweed pollen seasons. Samples were taken at a height of 1.5 M. during 5-to 20-minute periods. Tests were grouped by pollen type, location, year, and direction of the wind relative to the line. Data were analyzed to evaluate variability without regard to sampler spacing and variability as a function of separation distance. The mean, standard deviation, coefficient of variation, ratio of maximum to the mean, and ratio of minimum to the mean were calculated for each test, each group of tests, and all cases. The average coefficient of variation is 0.21, the maximum over the mean, 1.39 and the minimum over the mean, 0.69. No relationship was found with experimental conditions. Samples taken at the minimum separation distance had a mean difference of 18 per cent. Differences between pairs of samples increased with distance in 10 of 13 groups. These results suggest that airborne pollens are not always well mixed in the lower atmosphere and that a sample becomes less representative with increasing distance from the sampling location.

Temporal variability in airborne pollen concentrations.

Tests were conducted to determine the relationship between concentrations of airborne pollens and sampling time, using sequential rotoslide samplers at urban and rural locations. Short-period data showed an increase in variability with time between samples. Two-hour data showed a stronger trend for the first 12 hours but better agreement as the time between samples approached one day.

Correlation between clinical and radiological diagnosis for fractures and dislocations in an accident department.

Clinicians and radiologists agreed on the presence or absence of fracture or dislocation in 897 of 1011 cases (89%). The agreement was closer in cases that were thought on clinical grounds to show no injury. We think the high incidence of agreement in this group should help to reduce the number of radiographs used in an accident department. Further analysis of the results indicates which areas of the body have most missed fractures.