DNA markers for nervous system diseases

Recombinant DNA technology has provided a vast new source of DNA markers displaying heritable sequence variation in humans. These markers can be used in family studies to identify the chromosomal location of defective genes causing nervous system disorders. The discovery of a DNA marker linked to Huntington's disease has opened new avenues of research into this disorder and may ultimately permit cloning and characterization of the defective gene.     

Different cultures,different values: The role of cultural variation in public’s WTP for marine species conservation

Understanding the cultural variation in public preference for marine species is a necessary pre-requisite if conservation objectives are to include societal preferences in addition to scientific considerations. We report the results of a contingent study undertaken at three case-study sites: Azores islands (Portugal), Gulf of Gdansk (Poland) and Isles of Scilly (UK). The study considered species richness of five specific marine taxa (mammals, birds, fish, invertebrates and algae) as proxies of marine biodiversity and the aim of analysis was to estimate from a multi-site perspective public’s willingness to pay (WTP) to avoid increased levels of species loss (reduction of species richness) for different marine taxa. Results, based on 1502 face-to-face interviews, showed that income, education and environmental awareness of the respondents were significant predictors of WTP for marine species conservation. Results also indicated that respondents in each of the European locations had different preferences for marine taxa. In the Azores, although mammals and fish were valued highly, small differences occurred in the WTP among different taxa. Respondents in the Isles of Scilly put a relatively low value on fish while algae and marine mammals were highly valued. In Gdansk, respondents defined a clear order of preference for marine mammals > fish > birds > invertebrates and algae. These findings suggested that cultural differences may be important drivers of valuation and undermines the commonly held premise that charismatic/likeable taxa consistently have a disproportionately strong influence on WTP for biodiversity conservation. We conclude that conservation policy must take account of cultural diversity alongside biological diversity.     

Congenital polycystic kidney disease in lambs

AIM: To describe the pathology and inheritance of a congenital polycystic kidney disease (PKD) of sheep.

METHODS: Mode of inheritance of PKD was investigated by evaluation of results of the disorder from planned matings in two consecutive years within subsets of a flock that had a high prevalence of PKD in lambs. Gross pathological and histopath- ological studies were based on tissues derived from this study. Haematoxylin and eosin (H&E)-stained paraffin sections of kidney, liver, extrahepatic biliary and pancreatic ducts, pancreas and epididymis were used to describe the lesions.

RESULTS: Twenty-five lambs affected by PKD, of both sexes, were born, numbers in accord with those expected for an autosomal recessive disorder in the population studied. In all cases for which tissues were available, the renal, bile ductal (intrahepatic and extrahepatic), pancreatic and epididymal tissues had widespread dysplastic changes and associated cyst formation.

CONCLUSIONS: The findings of renal cysts in conjunction with cysts in other organs are unifying features in many of the human and animal forms of PKD and suggest a related pathogenic and genetic base consistent with an autosomal recessive disorder.     

A survey for avian paramyxoviruses and influenza viruses in feral pigeons and native birds in New Zealand

Extract

Abstract

Avian paramyxoviruses (PMV) and influenza viruses have been readily isolated from free-living birds throughout the world(1) Alexander, DJ. 1980. Avian paramyxoviruses. Veterinary Bulletin, 50: 737–752.  [Google Scholar] (2) Alexander, DJ. 1982. Avian influenza: Recent developments. Veterinary Bulletin, 52: 341–359.  [Google Scholar] and, in New Zealand, both these viruses have been isolated from wild waterfowls, particularly ducks(3) Austin, FJ and Hinshaw, VS. 1984. The isolation of influenza A viruses and paramyxoviruses from ducks in New Zealand. Australian Journal of Experimental Biology and Medical Sciences, 62: 355–360.  [Google Scholar] (4) Stanislawek, W. 1992. Survey of wild ducks for evidence of avian influenza viruses, 1989 and 1990. Surveillance, 19(1): 21–22.  [Google Scholar]. It is widely known that free-living birds could harbour PMV and influenza viruses and could act as natural reservoirs of these viruses. They have occasionally caused Newcastle disease (PMV-1) and influenza outbreaks in commercial poultry farms throughout the world(5) Turner, AJ. 1976. The isolation of fowl plague virus in Victoria. Australian Veterinary Journal, 52: 384–384.  [Google Scholar] (6) Johnson, DC, Maxfield, BG and Moulthroo, JI. 1977. Eoidemioloeic studies of the 1975 avian influenza outbreak in chickens in Alabama. Avian Disease, 21: 161–177.  [Google Scholar] (7) Alexander, DJ, Parsons, G and Marshall, R. 1984. Infection of fowls with a Newcastle disease virus by food contaminated with pigeon faeces. Veterinary Record, 115: 601–602.  [Google Scholar] (8) Forsyth, WM, Grix, DC and Gibson, CA. 1993. Diagnosis of highly pathogenic avian influenza in chickens: Bendigo 1992. Australian Veterinary Journal, 70: 118–119.  [Google Scholar]. However, similar outbreaks have not been reported from New Zealand.     

Allozyme variation amongst populations of the freshwater crab,Potamonautes perlatus (Decapoda: Potamonautidae) in the Berg River system,Western Cape

The Cape river crab, Potamonautes perlatus, is widely distributed in streams and rivers of the Western Cape where it exhibits considerable morphological variation. Recent genetic work on populations in the Olifants River system has demonstrated the existence of a new cryptic species of river crab, while populations of P. perlatus in the nearby Berg River system remained uninvestigated. Six populations of P. perlatus were collected from along the length of the Berg River system (125 km) and the genetic structure was investigated using allozyme electrophoresis. Results from 14 allozyme loci showed that the populations were genetically invariant across the river system. It is suggested that gene flow may be responsible for the poor genetic differentiation amongst populations in the Berg River system. The implication for future management of the system is briefly discussed.     

Comparative cardiovascular, analgesic, and sedative effects of medetomidine, medetomidine–hydromorphone, and medetomidine–butorphanol in dogs

The purpose of this study was to determine the cardiovascular, analgesic, and sedative effects of IV medetomidine (M, 20 µg kg^?1), medetomidine–hydromorphone (MH, 20 µg kg^?1 ? 0.1 mg kg^?1), and medetomidine–butorphanol (MB, 20 µg kg^?1 ? 0.2 mg kg^?1) in dogs. Using a randomized cross‐over design and allowing 1 week between treatments, six healthy, mixed‐breed dogs (five males and one female) weighing 20 ± 3 kg, were induced to anesthesia by face‐mask administration of 2.9% ET sevoflurane to facilitate instrumentation prior to administration of the treatment combinations. Dogs were intubated and instrumented to enable measurement of heart rate (HR), systolic arterial pressure (SAP), mean arterial pressure (MAP), diastolic arterial pressure (DAP), mean pulmonary arterial pressure (PAP), pulmonary arterial occlusion pressure (PAOP), central venous pressure (CVP), pulmonary arterial temperature (TEMP), and cardiac output via thermodilution using 5 mL of 5% dextrose, and recording the average of the three replicate measurements. Cardiac index (CI) and systemic (SVR) and pulmonary vascular resistances were calculated. After instrumentation was completed, administration of sevoflurane was discontinued, and the dogs were allowed to recover for 30 minutes prior to administration of the treatment drugs. After collection of the baseline samples for blood gas analysis and recording the baseline cardiovascular variables, the test agents were administered IV over 10 seconds and the CV variables recorded at 5, 10, 15, 30, 45, and 60 minutes post‐injection. In addition, arterial blood was sampled for blood gas analysis at 15 and 45 minutes following injection. Intensity and duration of analgesia (assessed by toe‐pinch response using a hemostat) and level of sedation were evaluated at the above time points and at 75 and 90 minutes post‐injection. Data were analyzed using anova for repeated measures with posthoc differences between means identified using Bonferroni's method (p < 0.05). Administration of M, MH, or MB was associated with increases in SAP, MAP, DAP, PAP, PAOP, CVP, SVR, and TEMP and with decreases in HR and CI. No differences in CV variables between treatment groups were identified at any time. PaO₂ increased over time in all groups and was significantly higher when MH was compared with M. At 45 minutes, PaO₂ tended to decrease over time and was significantly lower when MH and MB were compared with M at 15 minutes. Analgesia scores for MH and MB were significantly higher compared with M through 45 minutes, while analgesia scores for MH were significantly higher compared with M through 90 minutes. Sedation scores were higher for MH and MB compared with M throughout 90 minutes. Durations of lateral recumbency were 108 ± 10.8, 172 ± 15.5, and 145 ± 9.9 minutes for M, MH, and MB, respectively. We conclude that MH and MB are associated with improved analgesia and sedation and have similar CV effects when compared with M.