Defining occult injuries of the distal forearm and wrist in children.

PURPOSE: The nonspecific terms "wrist sprain" and "suspected occult bony injury" are frequently documented as diagnoses in occult paediatric wrist injuries. To date, however, no one has accurately defined their true underlying pathology. The primary objective of this study was to identify the true pathoanatomy of occult acute paediatric wrist injuries. Our secondary objective was to compare our findings with existing adult data in order to determine any population differences that might be clinically relevant. METHODS: We performed a single-centre retrospective case series evaluating MRI findings in acute paediatric wrist injuries presenting to the hand injury unit between 2011 and 2014. All patients underwent standardised radiographs of the wrist and, where clinically indicated, of the scaphoid. Where no bony anomaly was identified, MRI scanning was offered. Cohen's kappa coefficient was used to calculate the agreement between clinical and MRI diagnosis. RESULTS: 57 patients met the final inclusion criteria. Occult fractures and bony contusions comprised the majority of the pathologies, at 36.5 and 35.0 %, respectively. There were no cases of isolated soft-tissue injury. MRI effected management change in 35.1 % of cases. Paediatric wrists demonstrated differences in injury pattern and distribution when compared to an adult population. CONCLUSION: This study defines for the first time the true pathology of occult paediatric wrist injuries. The current definition of a wrist sprain was not applicable to a single case and therefore appears to be inappropriate for use in the paediatric population. A precise knowledge of the likely pathology facilitates accurate information delivery whilst reducing parental uncertainty and treatment variation.

Nothing new under the heavens: MIH in the past?

AIM: This was to study an archaeological population of subadult teeth in 17th and 18th century skeletal material from a London (England) cemetery for enamel defects including molar-incisor-hypomineralisation (MIH). METHODS: Dentitions of 45 sub-adults were examined using standard macroscopic methods and systematically recorded. A total of 557 teeth were examined with a *5 lens and photographed. Ages of the individuals were estimated from their dental crown and root development stages and not from charts that combine tooth eruption with development stages. The dental age of the individual and the approximate age of onset of enamel defects was then calculated on the basis of the chronological sequence of incremental deposition and calcification of the enamel matrix. Affected enamel was graded macroscopically as: - Mild: <30% of the tooth's enamel surface area visibly disrupted (this encompasses the entire range reported in most other studies), Moderate: 31-49% of the tooth's enamel surface area visibly disrupted and Severe: >50% of the tooth's enamel surface area visibly disrupted. RESULTS: Of the total number of individuals 41 (93.2%) showed signs of enamel developmental dysplasia or MIH, 28 of them showing moderate or severe lesions of molars, primary or permanent (63.6% of the sample). Incisors and canines, though surviving much less often, showed episodes of linear hypoplasia. CONCLUSION: The extensive lesions seen on many of the molars displayed cuspal enamel hypoplasia (CEH). Many of these teeth also exhibited Molar Incisal Hypomineralisation (MIH).

Gross enamel hypoplasia in molars from subadults in a 16th-18th century London graveyard.

Dental Enamel Hypoplasia has long been used as a common nonspecific stress indicator in teeth from archaeological samples. Most researchers report relatively minor linear and pitted hypoplastic defects on tooth crown surfaces. In this work we report a high prevalence and early age of onset of extensive enamel defects in deciduous and permanent molars in the subadults from the post-medieval cemetery of Broadgate, east central London. Analysis of the dentition of all 45 subadults from the cemetery, using both macroscopic and microscopic methods, reveals disturbed cusp patterns and pitted, abnormal and arrested enamel formation. Forty-one individuals from this group (93.2%) showed some evidence of enamel hypoplasia, 28 of them showing moderate or extensive lesions of molars, deciduous or permanent (63.6% of the sample). Scanning Electron Microscope images reveal many molars with grossly deformed cuspal architecture, multiple extra cusps and large areas of exposed Tomes' process pits, where the ameloblasts have abruptly ceased matrix production, well before normal completion. This indented, rough and poorly mineralized surface facilitates both bacterial adhesion and tooth wear, and when such teeth erupt fully into the mouth they are likely to wear and decay rapidly. We suggest that this complex combination of pitted and plane-form lesions, combined with disruption of cusp pattern and the formation of multiple small cusps, should henceforth be identified as "Cuspal Enamel Hypoplasia."

Hyperkeratosis in athymic nude mice caused by a coryneform bacterium: microbiology, transmission, clinical signs, and pathology.

The purpose of this study was to characterize a spontaneous disease condition causing hyperkeratosis in nude mice and to explore the etiologic role of a particular species of coryneform bacteria in this disease, colloquially known as "scaly skin disease." The study was divided into two parts. In the first phase, a series of inoculation experiments was conducted with a field isolate of the coryneform species used to study the clinical and histopathologic development of the disease syndrome. Athymic nude mice (4 to 5 weeks old) were inoculated on the skin of the back with a suspension of a pure culture of the coryneform bacterium that had been isolated from a field case. The culture was applied with a sterile cotton swab in concentrations varying from 6.1 x 10(4)/ml to 5.0 x 10(7)/ml. All inoculated mice became persistently infected throughout the 33 days of the experiment. Clinically evident hyperkeratosis in inoculated animals developed more frequently in mice housed in a microisolator cage than in a semi-rigid isolator and more frequently in mice inoculated with higher numbers of organisms. In all animals in which hyperkeratosis developed, it was first noted on day 7 after inoculation. The second series of experiments was designed to determine the success of various housing methods in excluding the infection, mechanisms of transmission, susceptibility of other stocks and strains of mice to the organism, and whether the other strains might serve as a source of the organism. Results of the study in various strains indicated that both immunocompetent and immunodeficient mice, whether glabrous or hirsute, could be infected with the organism, but only glabrous animals developed hyperkeratosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Anaesthetic effects of chloral hydrate, pentobarbitone and urethane in adult male rats.

Chloral hydrate, pentobarbitone and urethane were evaluated and compared for onset, duration and depth of anaesthesia, cardiovascular and respiratory effects, nociception and mortality in adult male rats. Chloral hydrate (300 and 400 mg/kg) severely depressed the cardiovascular and respiratory systems. Duration of anaesthesia was linearly related to dose, and anaesthetic depth and analgesia were excellent. Pentobarbital (40 mg/kg) produced a short period of light surgical anaesthesia. Moderate to severe respiratory and cardiovascular depression occurred. Duration of anaesthesia was not related to dose. Urethane (1.2 and 1.5 g/kg) caused moderate cardiovascular depression. In addition, mortality was high at the 1.5 g/kg dose. Duration of anaesthesia was greater than 24 h for most animals. Anaesthesia depth and analgesia were excellent.

The postschool adjustment of persons with learning disabilities: current status and future projections.

Recent research on the adult status of individuals with learning disabilities was reviewed. It was found that learning disabilities persist into adulthood, that manifestations of learning disabilities in adulthood are different than in childhood, and that many adults with learning disabilities are not independent or self-sufficient. These findings are related to the changes American society is currently undergoing, particularly changes in the workplace. Implications for teachers are discussed.

Three-year analysis of characteristics of learning disabled students in self-contained classrooms and resource rooms.

The present investigation examined the characteristics of school-identified learning disabled students from a large metropolitan school district in Tennessee. While it corroborated several findings of previous surveys of such students, this report also supplemented the literature by comparing the differences within a three-year span of time between school-identified learning disabled students who were assigned to self-contained classrooms and those who were assigned to resource rooms. Among the major findings were the presence of initial differences in IQ between self-contained and resource room students, the absence of differences in initial achievement scores between these two groups, and a decline over time in IQ, arithmetic, and spelling scores for both groups.

Use of cage space by guineapigs.

Cage space requirements for laboratory animals have been established by Government Regulation and Recommendations. In order to test the adequacy of these space allocations, the use of cage floor area by breeding groups of guineapigs was studied. A computer-coupled video tracking system capable of imaging in low light intensity as well as total darkness was used to determine the average per cent occupancy by guineapigs in all portions of a cage over 12-h light and dark cycles. Simultaneous time synchronized slow motion video recordings permitted an analysis of activity to be coordinated with cage use data. Results of the study revealed that breeding groups of guineapigs utilize the periphery of the cage almost to the total exclusion of the centre of the cage. Approximately 75-85% of all occupancy in both the day and evening hours occurred in 47% of the cage floor area located along the periphery. Analysis of video recordings revealed that the animals remained active throughout the day and night with no prolonged period of quiescence that could be associated with sleep. Results of this study suggest that while guidelines for housing guineapigs based on area allocation per animal can be formulated and are easy to administer, they cannot be supported by the behavioural characteristics of these animals or careful quantitation of their pattern of cage space utilization.

Effectiveness of skin absorption of tincture of I in blocking radioiodine from the human thyroid gland.

Topical application of tincture of iodine (I) was found to be effective in blocking the thyroid uptake of orally administered 131I in humans. Abdominal skin application of tincture of I resulted in an approximately 82% reduction in the uptake of 131I by the thyroid gland. The effectiveness varied among individuals and may have depended on the quantity applied and on the application site. In each study group, elevated levels of serum I were observed.

An evaluation of intra-cage ventilation in three animal caging systems.

Although temperature and relative humidity have been quantitated and their effects on research data studied, few studies have measured the air turnover rates at cage level. We evaluated the air distribution and air turnover rates in unoccupied shoe-box mouse cages, filter-top covered cages and shoe-box mouse cages housed in a flexible film isolator by using discontinuous gas chromatography/mass spectrometry and smoke. Results showed that air turnover was most rapid in the unoccupied shoe-box mouse cage and slowest in the filter-top covered cage. Placing mice in the filter-top covered cage did not significantly improve the air turnover rate. Although filter-top covered cages reduce cage-to-cage transmission of disease, the poor airflow observed within these cages could lead to a buildup of gaseous pollutants that may adversely affect the animal's health.

The effects of topical povidone I solution on serum iodide levels and thyroid uptake of 131I in dogs.

Topical application of povidone I solution in dogs has been found to be effective in producing significant elevations in serum iodide concentrations within 2 h after application. Among dogs treated with this preparation 2 h before oral administration of 131I, significant thyroid blocking persisted for at least 72 h.

An evaluation of analgesia associated with the immobility response in laboratory rabbits.

The immobility response (IR) was studied in rabbits to evaluate its analgesic properties and reliability as a method of restraint. The participation of the endogenous opioid system in IR was studied indirectly by evaluating the effects of the narcotic antagonist naloxone on this phenomenon. Twenty-four adult New Zealand White rabbits were subjected to six noxious stimuli while restrained by IR and while restrained under control conditions. Testing on each animal was repeated under both conditions following the administration of naloxone. The noxious stimuli consisted of three levels of electric shock (10 volts, 30 volts, and 50 volts) applied to the shaved forearm, and mechanical pressure applied to the pinna, front toe, and hind toe. Withdrawal and changes in blood pressure, heart rate, and respiration were used as indicators of pain perception. Distress associated with noxious electrical and pressure stimulation was significantly reduced by IR, which suggested that the phenomenon does have a significant analgesic component. However, the rabbits showed wide variability in their susceptibility to IR induction, and even animals which did not withdraw in response to noxious stimulation under IR sometimes exhibited physiological changes suggestive of distress. Therefore, IR should not be considered as a reliable or humane alternative to analgesic/anesthetic drugs for laboratory rabbits. Naloxone had little effect on IR or IR-associated analgesia.

Cilia-associated respiratory (CAR) bacillus infection of obese mice.

Cilia-associated respiratory (CAR) bacillus was identified in respiratory tract lesions of obese mice dying of chronic respiratory disease. Neither Mycoplasma pulmonis nor pathogenic bacteria were isolated from cultures of the lesions at necropsy, but there was serologic and histologic evidence of respiratory virus infection. Cranial-ventral areas of lung were firm and demarcated from unaffected lung at gross examination, and representative tissue sank in water. Microscopically, there was suppurative bronchopneumonia with extensive peribronchiole lymphocyte and plasma cell proliferation. The affected bronchiole epithelium was covered with a sheet of slightly basophilic, filamentous, gram negative bacteria. Bronchioles with lesser amounts of lymphocyte accumulations contained lesser amounts of filamentous bacteria. Bronchioles without filamentous bacteria lining the respiratory epithelium lacked peribronchiole lymphocyte accumulations. There was a high correlation between CAR bacillus-positive serology and the identification of diagnostic histologic lesions. CAR bacillus was readily stained using immunohistochemical methods, and the ultrastructural features were similar to that described in rat infections.

A comparison of pentobarbital, fentanyl-droperidol, ketamine-xylazine and ketamine-diazepam anesthesia in adult male rats.

Proper use of anesthetics is of paramount importance for humane animal care. Current research trends show a greater reliance on rats for laboratory investigations. This study compared several dosages for four different drugs, (pentobarbital, fentanyl-droperidol, ketamine-xylazine and ketamine-diazepam) for use in the laboratory rat. Each drug was evaluated in respect to its onset, duration of effect, recovery, adverse effects and mortality. A quantitative assessment of the depth of anesthesia also was obtained for all dosages of each drug. Results showed that all tested dosages of pentobarbital, ketamine-xylazine and ketamine-diazepam were suitable anesthetics for use in the laboratory rat. Low dosages of fentanyl-droperidol (Innovar-Vet), however, appeared to produce a state known as neuroleptanalgesia as opposed to anesthesia seen with the other agents.

The effects of pentobarbital, fentanyl-droperidol, ketamine-xylazine and ketamine-diazepam on noxious stimulus perception in adult male rats.

The increased use of rats for laboratory studies has increased the urgency for a better understanding of their perception of painful or noxious stimuli and the means of obtunding such stimuli. Four different injectable drugs, pentobarbital, fentanyl-droperidol (Innovar-Vet), ketamine-xylazine and ketamine-diazepam, were evaluated in this study. Unlike previous studies in rodents, this study has quantitated noxious stimulus perception following a temporal sequence of observations. Results showed the greatest inhibition of noxious stimulus perception with Innovar-Vet, lesser inhibition with ketamine-xylazine and ketamine-diazepam, and the least obtunding of nociception with pentobarbital. Results of this study also suggested that a spatial orientation, similar to that present in man, exists within the CNS of rats for receipt of noxious stimulation.

The effects of pentobarbital, fentanyl-droperidol, ketamine-xylazine and ketamine-diazepam on core and surface body temperature regulation in adult male rats.

Many commonly used anesthetics cause hypothermia by inhibiting central and peripheral thermoregulatory mechanisms. Although it is probable that a loss of thermal homeostasis contributes directly to the high mortality frequently reported following anesthesia of laboratory rodents, this adverse effect has been investigated rarely in the past. This study compared the effects of three parenteral anesthetics (pentobarbital, ketamine-xylazine and ketamine-diazepam) and a neuroleptanalgesic (fentanyl-droperidol) on core and surface body temperature regulation in rats. Results showed a profound hypothermia with all dosages of pentobarbital, while ketamine-xylazine and ketamine-diazepam caused a dose-dependent depression in core and surface body temperature. All dosages of fentanyl-droperidol (Innovar-Vet) caused minimal depression in thermoregulation, suggesting that it is the drug which requires the least external thermal support. Results of this study also suggested that inability to compensate for heat loss, particularly from the body core, may profoundly influence anesthetic toxicity and the safety of anesthetic procedures.

The effects of pentobarbital, fentanyl-droperidol, ketamine-xylazine and ketamine-diazepam on arterial blood pH, blood gases, mean arterial blood pressure and heart rate in adult male rats.

Although anesthetics are known to cause respiratory and cardiovascular depression in humans, these adverse effects rarely have been investigated in laboratory rodents. This study evaluated the effects of four different injectable drugs, pentobarbital, fentanyl-droperidol (Innovar-Vet), ketamine-xylazine and ketamine-diazepam on the respiratory and cardiovascular systems of rats. Results showed marked acidosis, hypercarbia and hypoxia with high doses of Innovar-Vet, moderate respiratory depression with all dosages of pentobarbital and minimal respiratory depression with ketamine-xylazine and ketamine-diazepam. Innovar-Vet, ketamine-xylazine and pentobarbital caused profound hypotension, particularly at high dosages, while ketamine-diazepam caused the least depression in mean arterial blood pressure of all drugs evaluated. None of the drugs studied produced significant alterations in heart rate. Throughout all dosages investigated, the ketamine-diazepam combination showed the least overall effects on ventilation and perfusion of the four parenteral drug combinations studied.

Pharmacokinetics of cefazolin in guinea pigs.

The occurrence of antibiotic-related enterocolitis in guinea pigs restricts the use of many common antibiotics in this species. Cephaloridine, an antibiotic frequently recommended for this species, is no longer available and a substitute has yet to be explored. In this study, the potential therapeutic efficacy of cefazolin, also a first generation cephalosporin, was evaluated in guinea pigs by assessing pharmacokinetics, toxicity and the minimal inhibitory concentration for selected animal pathogens. Pharmacokinetics and toxicity were evaluated in four phases: single intramuscular injections, multiple intramuscular injections over 30 hours, multiple intramuscular injections over 5 days, and serum-protein binding studies. Antibiotic-related enterocolitis and irritation at the injection site occurred following high (100 mg/kg) repeated doses. At all dose levels, blood values exceeded the minimum inhibitory concentration for Bordetella bronchiseptica for only 1 hour postinjection. For Streptococcus and Staphylococcus sp., the drug half-life was 0.5 hours with peak concentrations occurring within 0.25 hours of injection. The volume of distribution of 0.5 l/kg indicated that there was extensive tissue distribution. Serum protein binding was approximately 85%. The short half-life and rapid plasma clearance rate (10.4 ml/min/kg) indicated that cefazolin is eliminated very rapidly from the guinea pig and may be of questionable therapeutic value.