A strategy for structuring and reporting a read-across prediction of toxicity.

Category formation, grouping and read across methods are broadly applicable in toxicological assessments and may be used to fill data gaps for chemical safety assessment and regulatory decisions. In order to facilitate a transparent and systematic approach to aid regulatory acceptance, a strategy to evaluate chemical category membership, to support the use of read-across predictions that may be used to fill data gaps for regulatory decisions is proposed. There are two major aspects of any read-across exercise, namely assessing similarity and uncertainty. While there can be an over-arching rationale for grouping organic substances based on molecular structure and chemical properties, these similarities alone are generally not sufficient to justify a read-across prediction. Further scientific justification is normally required to justify the chemical grouping, typically including considerations of bioavailability, metabolism and biological/mechanistic plausibility. Sources of uncertainty include a variety of elements which are typically divided into two main issues: the uncertainty associated firstly with the similarity justification and secondly the completeness of the read-across argument. This article focuses on chronic toxicity, whilst acknowledging the approaches are applicable to all endpoints. Templates, developed from work to prepare for the application of new toxicological data to read-across assessment, are presented. These templates act as proposals to assist in assessing similarity in the context of chemistry, toxicokinetics and toxicodynamics as well as to guide the systematic characterisation of uncertainty both in the context of the similarity rationale, the read across data and overall approach and conclusion. Lastly, a workflow for reporting a read-across prediction is suggested.

The cloning, expression, and nucleotide sequence of a gene coding for an immunogenic Brucella abortus protein.

Brucella abortus is the causative agent for brucellosis in cattle and man. Development of a single diagnostic test for the differentiation of vaccinated from infected animals and the development of a nonviable 'subunit' vaccine are top priorities of the brucellosis research program in the United States. Preliminary evidence previously showed that a purified 31-kDa protein (thought to be localized at or near the bacterial cell surface) protects against experimental brucellosis in rodents. The gene for this 31-kDa protein has now been cloned in Escherichia coli. The protein is expressed well, apparently from its native promoter, when placed in several different E. coli plasmids. The nucleotide sequence of the flanking and encoding sequences has been determined, and comparison with the N-terminal amino acid (aa) sequence of the mature protein indicates the presence of a putative 28-aa signal sequence. The availability of the 31-kDa protein free of Brucella contaminants now allows rigorous study of the immunological properties of this protein.

Fluorocarbocyclic nucleosides: synthesis and antiviral activity of 2'- and 6'-fluorocarbocyclic 2'-deoxy guanosines.

A series of four isomeric 2'- and 6'-fluorocarbocyclic guanosine analogues have been prepared and evaluated as potential anti-herpes agents. The racemic 2' beta-fluoro isomer 2-amino-1,9-dihydro- 9-[(1 alpha, 2 alpha, 3 beta, 4 alpha)-2-fluoro-3-hydroxy-4- (hydroxymethyl)cyclopentyl]-6H-purin-6-one (11a, C-AFG) and its 2' alpha-fluoro epimer 11b plus the chiral 6' beta-fluoro isomer 2-amino-1,9-dihydro-9-[[1S-(1 alpha, 2 alpha, 3 alpha, 4 beta)]- 2-fluoro-4-hydroxy-3-(hydroxymethyl)cyclopentyl]-6H-purine-6-one (11c) and its 6' alpha-fluoro epimer 11d were prepared from their respective fluoro amino diol hydrochlorides (6a,d). For comparison, the furanosyl compound 9-(2'-deoxy-2'-fluoro-beta-D-arabinofuranosyl)guanine (17, AFG) was prepared by coupling 2-amino-6-chloropurine with 2-deoxy-2-fluoro-3,5-di-O-benzoyl-alpha- D-arabinofuranosyl bromide followed by base hydrolysis. The 6' alpha-fluoro derivative 11d exhibited comparable activity to that of acyclovir (ACV) against herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) in vitro but was greater than 30-fold more active than ACV against HSV-1 and HSV-2 in vivo in the mouse systemic model. The 2' beta-fluoro derivative (11a, C-AFG) was extremely potent in vitro against HSV-1 and HSV-2 (ID50 0.006 and 0.05 micrograms/mL) and in vivo it was greater than 2 orders of magnitude more potent than ACV against HSV-1 and 70-fold more potent against HSV-2. The 2' alpha-fluoro 11b and 6' beta-fluoro 11c isomers were much less active.

Fluoro carbocyclic nucleosides: synthesis and antiviral activity of 2'- and 6'-fluoro carbocyclic pyrimidine nucleosides including carbocyclic 1-(2-deoxy-2-fluoro-beta-D-arabinofuranosyl)-5-methyluracil and carbocyclic 1-(2-deoxy-2-fluoro-beta-D-arabinofuranosyl)-5-iodouracil.

The racemic carbocyclic 2'-fluoroarabinosyl pyrimidine nucleosides 8, 9 (C-FIAU), 12, and 13 (C-FMAU) and the 2'-fluororibosyl pyrimidine nucleosides 17, 20, and 21 were prepared from their respective protected 2'-fluoro amino diols 5 and 14. The carbocyclic 2'-2'-difluorothymidine analogue 27 was obtained from the protected difluoro amino diol 24 which was prepared from the ketone 23 and (diethylamino)sulfur trifluoride (DAST). The chiral carbocyclic 2'-deoxy-6'-fluorouridines 33, 34, 38, and 39 were synthesized from the protected 6'-fluoro amino diols 30 and 36, which were prepared by reduction of the azides 28 and 35. C-FMAU (13) and C-FIAU (9) were active in vitro against HSV-1 with ID50 values of 4.4 and 11 micrograms/mL, respectively, but they were inactive against HSV-2. The cytidine analogues 12 and 20 displayed modest activity in vitro against HSV-1 and HSV-2 but were inactive against human influenza A virus.

Primary replacement of the fractured radial head with a metal prosthesis.

Compression testing of cadaver specimens showed that excision of the radial head allowed proximal radial displacement. The insertion of a metallic radial head restored normal mechanics, while a silicone rubber implant did not. We reviewed 31 of 36 comminuted fractures of the radial head, 21 associated with dislocation or ulnar fracture, which had been treated by primary replacement with a Vitallium prosthesis. At a mean follow-up of 4.5 years, there was reliable restoration of stability and prevention of proximal radial migration. There had been no dislocations or prosthetic failures, but two implants had been removed for loosening. The prosthesis is recommended for use as a spacer to stabilise the elbow after severe injuries while the soft tissues heal.

Induction of circulating interferon in calves with three different types of double stranded ribonucleic acid.

Three double-stranded ribonucleic acids (dsRNA), given intravenously, were evaluated for interferon induction in calves. Groups of four calves were given an initial injection then, 24 h later, a second injection of each dsRNA material. The synthetic dsRNA, poly I.poly C, at 0.5 mg/kg stimulated serum interferon in two calves after an initial injection and in three calves after a second dose, whereas a natural dsRNA (BRL 5907) at 0.5 mg/kg induced interferon in only one calf after both injections. A polyquaternary ammonium complex (BRL 10739) of natural dsRNA, at 0.1 mg/kg, induced interferon in all four calves after a single injection and circulating interferon persisted longer than with the other two dsRNA materials.

Continued studies on the adjuvancy effect of natural and synthetic double-stranded RNA preparations with inactivated Newcastle disease vaccines in fowls.

The adjuvant effect of the natural ds-RNA, BRL 5907, with inactivated Newcastle disease vaccines was confirmed using different oil-based formulations and could be given either as single injections or separately at adjacent sites. A minimum dose level of 0-04 mg BRL 5907 per bird was required for a significant enhancement of antibody levels following vaccination. While the synthetic ds-RNA Poly IC gave a similar response to that observed with BRL 5907, no significant effects could be detected with two other natural ds-RNA materials.

Further studies on the adjuvant effect of an interferon inducer (BRL 5907) on Newcastle disease and avian influenza inactivated vaccines.

Vaccination of fowls with inactivated Newcastle disease (ND) virus and avian influenza (AI) virus oil emulsion vaccines containing an interferon inducer (BRL 5907) produced an enhanced immunological response. The Newcastle disease vaccine containing BRL 5907 induced earlier protection to challenge than Newcastle disease vaccine by itself and also produced an increase immune response when administered to day-old maternally immune and susceptible chicks.

Acute calcification and carpal tunnel syndrome.

Carpal tunnel syndrome is a common diagnosis, and often there is no identifiable cause. We describe the case of a patient who developed acute symptoms secondary to calcification in the carpal tunnel. The patient was treated by decompression, and made a slow, but uneventful recovery.

Craniofacial morphology and tooth wear: a longitudinal study of orthodontic patients.

Previous research has suggested that a relationship exists between craniofacial morphology and tooth wear. The primary objective of this study was to determine whether an individual's craniofacial morphology during childhood is related to the degree of tooth wear that occurs in that same individual's adult dentition. Pretreatment orthodontic records taken during the mixed dentition (T1) and follow-up records taken an average of 20 years later (T2) were available for 165 orthodontic patients. Incisal/occlusal tooth wear was measured on a tooth-by-tooth basis from T1 and T2 casts using a four-category scoring system. Measures of craniofacial morphology were made from the T1 lateral cephalometric radiograph. Multiple regression analysis indicated that adult wear was associated with the T1 cephalometric measures of ANB (p = 0.017) and the interaction between ramal height and sex (p = 0.039). These results suggest that the craniofacial morphology observed during childhood has a small but significant relationship to adult tooth wear.

Bilateral fractured clavicles--a pair of cases.

The authors present two cases of bilateral fractured clavicles, both resulting from direct trauma to both shoulders. In both cases, the fractures healed uneventfully with non-operative treatment.

Sidewind reinforcement for above-elbow plaster slabs.

A method of reinforcing an above-elbow plaster slab is described. The technique prevents the splint becoming tight at the elbow and gives it considerable strength.

Nonaccidental injury in osteogenesis imperfecta: a case report.

A case of nonaccidental injury in a child with severe osteogenesis imperfecta (OI) is described. The problems of diagnosis of child abuse in this group of patients are discussed.

An evaluation of an inpatient psychiatric unit for children.

The progress of 31 children admitted over a 2 year period to a regional child psychiatric inpatient unit was studied using questionnaires and interviews. The effectiveness of the children's treatment was evaluated using an interrupted time series design. Substantial and significant improvements were observed for both global levels of disorder and specific problems, and this effect appeared to be stable. These results confirm previous assertions on the efficacy of inpatient treatment.

The enzymic hydrolysis of amygdalin.

Chromatographic examination has shown that the enzymic hydrolysis of amygdalin by an almond beta-glucosidase preparation proceeds consecutively: amygdalin was hydrolysed to prunasin and glucose; prunasin to mandelonitrile and glucose; mandelonitrile to benzaldehyde and hydrocyanic acid. Gentiobiose was not formed during the enzymic hydrolysis. The kinetics of the production of mandelonitrile and hydrocyanic acid from amygdalin by the action of the beta-glucosidase preparation favour the probability that three different enzymes are involved, each specific for one hydrolytic stage, namely, amygdalin lyase, prunasin lyase and hydroxynitrile lyase. Cellulose acetate electrophoresis of the enzyme preparation showed that it contained a number of enzymically active components.

Changes in the concentrations of free amino acids in milk during growth of Lactococcus lactis indicate biphasic nitrogen metabolism.

Analysis of the concentrations of free amino acids in milk during growth of Lactococcus lactis subsp, lactis revealed a biphasic pattern of change during the logarithmic phase. During the first period there was little overall change in the total concentration of amino acids in the medium. The second phase was characterized by increased net liberation of free amino acids. There were also qualitative differences in the amino acids that were taken up and utilized during each period. The concentrations of Val, Leu and Ile decreased only during the early phase, while those of Ser, Arg, Thr and Met decreased only during the second phase. Gly and Ala were utilized throughout logarithmic growth. Gly uptake appeared to be greater during the second period and accounted for the largest proportion of free amino acid utilization at this time. It is possible that the biphasic nature of amino acid nutrition was due to increased consumption in late log phase of peptides derived from milk proteins by proteolysis. Increased activity of the arginine deiminase pathway during late log phase was inferred from increased utilization of Arg and liberation of citrulline and ornithine.

A longitudinal study of tooth wear in orthodontically treated patients.

The primary objective of this study was to determine whether there is a relationship between incisal/occlusal tooth wear during the mixed dentition and subsequent wear of the adult dentition. Pretreatment orthodontic records taken during the mixed dentition (T1), as well as follow-up records taken an average of 20 years later (T2), were available for 223 orthodontically treated patients. Incisal/occlusal tooth wear was measured on a tooth-by-tooth basis from T1 and T2 stone casts with a four-category scoring system. Multiple regression analysis (R2 = 0.33) indicated that wear could be predicted at a given age during adulthood from wear observed on the deciduous mandibular canines and molars at T1 (p < 0.0001). This predictive relationship was modified by the age at which the T1 wear was observed (p = 0.029) and possibly by the sex of the patient (p = 0.10). These results indicate that adult tooth wear is not independent of the tooth wear that occurred as a child. Bruxism is suggested as a possible common etiologic mechanism that may account for the relationship between childhood and adult tooth wear.