Spinal Cord Hamartomatous Myelodysplasia in 2 Horses With Clinical Neurologic Deficits.

Two horses euthanized for neurologic deficits were diagnosed with hamartomatous myelodysplasia of the spinal cord. One was a 5-week-old Holsteiner colt exhibiting spasms of muscle rigidity in the extensor muscles of the limbs and epaxial muscles, and the other was a 3-year-old Thoroughbred colt exhibiting progressive ataxia and hypermetria in the pelvic limbs. Each had focal disorganization of the white and gray matter of the spinal cord forming a mass interspersed with neurons, glial cells, and disoriented axon bundles. In the Holsteiner colt, the mass was at the level of C5 and included islands of meningeal tissue contiguous with the leptomeninges. The mass occluded the central canal forming hydromyelia cranial to the occlusion. In the Thoroughbred colt, the mass was at the level of L1 on the dorsal periphery of the spinal cord and did not involve the central canal.

The survival of resin modified glass ionomer and stainless steel crown restorations in primary molars, placed in a specialist paediatric dental practice.

AIMS: To prospectively report on the survival of resin-modified glass ionomer cement (RMGIC), photac-fil and pre-formed stainless steel crown (SSC) restorations in primary molar teeth placed over a seven-year period in a specialist paediatric dental practice under private contract of remuneration. METHOD: All primary molar restorations placed by a specialist paediatric dentist over a seven-year period were reviewed and the outcome results recorded. Data were recorded at review visits until June 30, 2003. Data recorded included Class I restorations, Class II restorations and SSC. The Class II cavities were either mesial or distal, with or without buccal/palatal extensions. If both proximal surfaces were decayed or if after cavity preparation the resultant outline form was significantly larger than the minimal classical form, RMGIC was not used; an SSC was placed instead. Stainless steel crown preparation followed conventional guidelines. The crowns were cemented with reinforced zinc oxide and eugenol (Kalzinol). The status was recorded as satisfactory restoration, tooth exfoliated, tooth extracted for orthodontic reasons with the date of extraction, or needing replacement. If replaced then the reason for replacement was also recorded. RESULTS: A total of 544 Class I RMGICs, 962 Class II RMGICs, and 1,010 SSCs were placed. At the last review of each restoration, 98.3% of Class I, 97.3% of Class II RMGICs and 97.0% of SSCs were either satisfactory or withdrawn intact. CONCLUSION: Under the conditions of private specialist practice-based study SSCs continued to prove very successful for the restoration of larger cavities and for pulp-treated primary molar teeth. For the smaller cavities RMGIC were also very successful.

Massive Muscular Infection by a Sarcocystis Species in a South American Rattlesnake (Crotalus durissus terrificus).

Massive numbers of sarcocysts of a previously undescribed species of Sarcocystis were observed in the skeletal muscles throughout the body of an adult, female South American rattlesnake (Crotalus durissus terrificus). Examination of tissue sections by light microscopy demonstrated that sarcocysts were present in 20 to 40% of muscle fibers from 5 sampled locations. Sarcocysts were not present in cardiac muscle, smooth muscle, or other organs. Sarcocysts were 0.05-0.15 mm wide, had variable length depending on the viewed orientation and size of the muscle fiber, and had a sarcocyst wall less than 1-µm thick. Sarcocysts were subdivided by septa and had central degeneration in older sarcocysts. Host induced secondary encapsulation or an inflammatory response was not present. By transmission electron microscopy (TEM), the sarcocyst wall was Type I, with a parasitophorous membrane of approximately 100 nanometers in width arranged in an undulating pattern and intermittently folded inward in a branching pattern. The sarcocysts contained metrocytes in different stages of development and mature bradyzoites. The nucleic acid sequence from a section of the 18S small subunit rRNA gene was most closely related to S. mucosa that uses marsupials as intermediate hosts and has an unknown definitive host. This is apparently the third report of muscular Sarcocystis infection in snakes and is the first to describe the ultrastructure of the sarcocysts and use sequencing methods to aid in identification.

A rapid spectrophotometric method for assessing macrophage phagocytic activity.

The method described provides a rapid and inexpensive in vitro assay of phagocytosis by mononuclear phagocytes. This assay utilizes yeast cells, stained with congo red, as the target particle and quantitation is performed spectrophotometrically. An attractive feature of this assay is that phagocytic activity is assessed using large sample sizes, in this case approximately 1 X 10(6) macrophages per sample, resulting in a more accurate evaluation of phagocytosis than assays dependent on microscopic quantitation.

In vitro effect of aflatoxin B1 on rat liver macrophages (Kuffer cells).

The effect of aflatoxin B1 on the uptake and incorporation of [3H]leucine and [3H]uridine and on phagocytosis of latex particles was studied using cultures of rat liver macrophages (Kuffer cells). Aflatoxin B1 inhibited the incorporation of both isotopes, but inhibition of uridine incorporation was greater than that of leucine, suggesting that RNA synthesis was a major site of inhibition. Aflatoxin B1 also inhibited phagocytosis of latex particles in a time- and dose-dependent manner.

In vitro cytotoxicity of an Alcaligenes faecalis and its relationship in in vivo tracheal pathologic changes in turkeys.

Two isolates of Alcaligenes faecalis from turkeys with respiratory disease were indistinguishable physically, biochemically, and for specific agglutinating antibodies. The isolates differed in in vitro cytotoxicity for turkey tracheal organ cultures and in ability to induce clinical rhinotracheitis in poults. The isolate designated NCDp induced in vitro cytotoxic changes in turkey tracheal organ cultures. Additionally, poults inoculated with NCDp developed severe clinical signs of rhinotracheitis, flaccid (collapsing) trachea, bacterial colonization of the cilia, and degeneration and loss of the columnar epithelium from the anterior one third to one half of the trachea. The isolate designated NCDm induced little or no cytotoxic changes in turkey tracheal organ culture. Isolate NCDm caused mild clinical signs of rhinotracheitis and colonized the trachea of inoculated poults, but it caused no other observable changes. A correlation seems to exist between in vitro cytotoxicity and in vivo pathogenicity for these isolates of A. faecalis.

Cytotoxic activity of pathogenic Alcaligenes faecalis in turkey tracheal organ cultures.

Turkey tracheal organ cultures were used to study the virulence of Alcaligenes faecalis isolants that have been shown to be pathogenic for turkey poults. Viable infected and noninfected tracheal rings were examined by phase-contrast microscopy, and fixed stained sections were examined by light microscopy. Alcaligenes faecalis at concentrations of 10(8) and 10(9) colony-forming units/ml caused ciliostasis, hydropic degeneration (characterized by blebbing of the plasma membrane, cellular swelling, and cytoplasmic vacuolation), and eventual sloughing of the ciliated epithelium. Only ciliated epithelial cells appeared affected. For comparison, other bacterial isolants not pathogenic for turkeys were tried in this system. These bacterial isolants included 3 isolants of A faecalis from human beings and isolants of Klebsiella pneumoniae, Escherichia coli, and A faecalis from turkeys. Inoculation of each of these bacterial cultures onto tracheal organ cultures failed to produce the lesions described.

Homidium (ethidium) bromide inhibition of avian reovirus replication.

Homidium bromide inhibited replication of avian reovirus in cell culture. Inhibition was dose dependent, and the critical event required that the dye be present during the replicative viral cycle and was not attributable to a cellular function.

The fate and survival of amalgam and preformed crown molar restorations placed in a specialist paediatric dental practice.

The fate of 1688 amalgam restorations and 716 preformed crowns placed in permanent and primary molars in a specialist paediatric dental practice over a 10-year period by one operator is reported. For primary molar amalgams, the replacement rate, true failure rate and 5-year survival estimates were, for Class 1 restorations, 16.1%, 3.9%, 73.3%, respectively, with an estimated median survival time greater than 8.5 years, and for Class 2 cavities 14.7%, 11.6%, 66.6%, with an estimated median survival time greater than 7.5 years. For permanent molar amalgams, the replacement rate, true failure rate and 5-year survival estimates were for Class 1 restorations 11.5%, 6.5%, 76.8%, respectively, with an estimated median survival time greater than 9.3 years, and for Class 2 restorations 9.8%, 8.0%, 82.2%, with a median survival time greater than 8.5 years. For all preformed crowns, the replacement rate, true failure rate and 5-year survival estimates were 2.8%, 1.9%, 92.0%, and the estimated median survival time greater than 7.64 years. No relationship was observed between the age of the patient and the age of replaced restorations. No significant difference was found between the survival rates of Class 1 and 2 amalgam restorations in primary or permanent molars, nor between first and second primary molars.

A new oral surgery teaching model.

An anatomical model for teaching the practical aspects of routine oral surgery in a clinical or laboratory environment, is described. Replaceable sections allow the model to be rapidly re-used so that successive students may practise procedures such as incisions, flap reflection, bone removal, tooth removal, apicectomy and suturing. Keeping the cost per procedure to a minimum was considered to be of fundamental importance and this has been achieved through the use of 'factory produced' replacement parts.

Restoration of primary teeth affected by Early Childhood Caries.

AIM: This was to review the literature on Early Childhood Caries (ECC) for the approaches to prevention and restoration of affected primary teeth. METHODS: The methods are reviewed and suggestions made as the approaches necessary for treating very young children. The special problems associated with the need to restore primary incisors in children with very low levels of cooperation are described. The options are outlined and indications for each approach discussed.

One hospital's response to the fight against domestic violence.

The author discusses the vital role his hospital plays in the fight against domestic violence--the Project Safe Refuge and the Safe Refuge Advocate.

Aquatic toxicity of cationic surfactants to Daphnia magna.

Quantitative structure-activity relationship (QSAR) modelling of aquatic toxicity for cationic surfactants has received limited attention despite the fact that surfactants of this type are generally more toxic than predicted by general narcosis or polar narcosis equations. Here we report measurement of log P for three types of aromatic quaternary ammonium halides at sub-micellar concentrations, refinement of earlier rules for log P calculation, and development of a hydrophobicity based QSAR, using both calculated and measured log P values, for the aquatic toxicity of quaternary ammonium halides to Daphnia magna. The QSAR for cationics has a substantially larger intercept than the log P-based QSARs for nonionic and anionic surfactants. This is rationalised in terms of the head group interactions with membrane phospholipid in a two-dimensional partitioning model. The effect of the positive nitrogen on the log P contributions of methylene groups along alkyl chains varies, depending on the other groups bonded to the positive nitrogen. We propose a mechanistic explanation, but until these effects can be put on a more predictable quantitative basis it is recommended that, for quaternaries other than the three types discussed here, calculated log P values should not be relied on and experimental values should be determined, e.g. for prediction of toxicity by the QSAR equation reported here.

Review: behaviour management techniques in paediatric dentistry.

BACKGROUND: Behaviour management is widely agreed to be a key factor in providing dental care for children. Indeed, if a child's behaviour in the dental surgery/office cannot be managed then it is difficult if not impossible to carry out any dental care that is needed. It is imperative that any approach to behavioural management for the dental child patient must be rooted in empathy and a concern for the well being of each child. REVIEW: Based on various presentations given at Congresses of the European Academy of Paediatric Dentistry (EAPD), documents reviewing behaviour management prepared by the Clinical Affairs Committee of the EAPD, and written submissions to the Executive Board of the EAPD, a review of the various approaches to the behaviour management of the child dental patient was completed. All aspects of non-pharmacological behavioural management techniques described in the literature over the past 80 years were reviewed. FINDINGS: There is a very wide diversity of techniques used but not all are universally accepted by specialist paediatric and general dentists. Wide cultural and philosophical differences are apparent among European paediatric dentists that seem difficult to bridge when forming agreed guidelines. Accordingly, this review highlights those behaviour techniques that are universally accepted such as tell, show, do (TSD) or positive reinforcement, but nevertheless describes the most commonly mentioned techniques for which there are descriptions in the literature. CONCLUSION: A wide variety of behavioural management techniques are available to paediatric dentists which must be used as appropriate for the benefit of each child patient, and which, importantly, must take into account all cultural, philosophical and legal requirements in the country of dental practice of every dentist concerned with dental care of children.