An instability in neutron stars at birth

Calculations with a two-dimensional hydrodynamic simulation show that a generic Raleigh-Taylor-like instability occurs in the mantles of nascent neutron stars, that it is possibly violent, and that the standard spherically symmetric models of neutron star birth and supemova explosion may be inadequate. Whether this "convective" instability is pivotal to the supemova mechanism, pulsar magnetic fields, or a host of other important issues that attend stellar collapse remains to be seen, but its existence promises to modify all questions concerning this most energetic of astronomical phenomena.     

Plant-derived enzyme inhibitors and lectins for resistance against plant-parasitic nematodes in transgenic crops

Due to increasing restrictions on the use of toxic and expensive nematicides, there is now a greater than ever need for crop cultivars that are resistant to plant-parasitic nematodes. Genetically engineered nematode resistance is not as well developed as other engineered traits but, even so, the first genetically modified plants with enhanced nematode resistance have been produced and tested. Plant-derived enzyme inhibitor and lectin genes are being evaluated for their ability to confer broad-spectrum nematode resistance in transgenic crop plants. Early indications are that these are likely to be effective. Gene pyramiding has potential to increase field durability and to widen the spectrum of nematodes controlled by any one transgenic line. © 1998 SCI.     

The use of retrievable electrodes for recording gastric myoelectric activity after spontaneous gastric dilatation volvulus in dogs.

Gastric myoelectric activity was measured in 10 dogs with spontaneous gastric dilatation-volvulus (GDV). Myoelectric activity was recorded with temporary, retrievable wire electrodes placed on the serosal surface of the stomach after derotation and tube gastrostomy. Gastric myoelectric activity was recorded for 1 hour daily, beginning with the day of surgery (less than 24 hours), 24, 48, 72, 96, 120, 144, and 168 hours after surgery. Recordings were also obtained for 1 hour daily after feeding, beginning 24 hours after surgery. Bradygastria was the predominate dysrhythmia immediately after surgery and at hour 24. The mean slow wave frequency was more than normal at hours 48 to 168 due to an increase in tachygastria and arrhythmias. The slow wave frequency significantly decreased after feeding at hours 120 and 144. The overall mean percentage of dysrhythmias was significantly decreased after feeding at hour 72 only. The mean percentage of spike activity ranged from 37.7 +/- 12.5 to 75.7 +/- 6.2 throughout the 8-day study period. Thus, gastric myoelectric activity was disrupted in these dogs with spontaneous GDV and subsequent tube gastrostomy. Feeding did not greatly diminish these dysrhythmias.     

Milk Progesterone Profile at and after Artificial Insemination in Repeat-Breeding Cows: Effects on Conception Rate and Embryonic Death

The aim of this study was to investigate whether the skim milk progesterone concentrations at artificial insemination (AI) and day of rise of post-ovulatory progesterone concentration thereafter affect the conception and embryonic death rates in repeat-breeding cows. Milk samples were obtained from 96 repeat-breeding cows that failed to conceive to three or more AIs. The samples were taken from the cows at the day of AI and three times/week until day 45 post-AI. Skim milk was obtained after centrifugation and used for progesterone assay. The cows with a progesterone concentration more than 0.5 ng/ml at AI showed a significantly higher incidence of late embryonic death than those having a progesterone concentration<0.5 ng/ml at AI (p<0.01). As the progesterone level at insemination rose, conception rate declined. A negative correlation was shown between conception rate and skim milk progesterone level at AI. Of 56 cows showing a rise of progesterone to 1 ng/ml or more within 6 days after AI, 28 cows (50%) conceived. On the contrary, only eight of 39 cows (20.5%) conceived when the progesterone rose up to 1 ng/ml after day 6 post-AI. We concluded that increased progesterone concentration at the time of AI and delayed rise of progesterone post-AI might lead to decrease in fertility in repeat-breeding cows.     

Pathological Conditions of the Reproductive Organs of Male Stray Dogs in the Tropics: Prevalence, Risk Factors, Morphological Findings and Testosterone Concentrations

The objective of this study was to estimate the prevalence of and risk factors for pathological conditions of the reproductive organs in stray dogs under tropical conditions. Three hundred and eighteen dogs were examined post-mortem in the period from 1 July 2002 to 30 June 2003. Before killing, a blood sample (from the cephalic vein) for testosterone assay was taken. Pathological conditions of the reproductive organs were found in 135 of the dogs (42.5%) and in 175 of the testes (64.8%). The most frequent pathologies found were testicular degeneration, cryptorchidism, testicular hypoplasia and testicular tumours (in 15.1%, 6.6%, 6.6% and 5.4% of the dogs and 15.1, 4.6, 6.0 and 3.5 of the testes, respectively). Transmissible venereal tumour (TVT) was seen in 5.4% of the dogs. Testicular degeneration was more common in old dogs and underweight dogs (p < 0.05). Testicular tumours were 14.3 times more common in cryptorchid dogs. Age was another important factor for the development of testicular tumours (p < 0.05). Lower levels of testosterone concentration (p < 0.05) were observed in dogs with advanced testicular degeneration (0.7 +/- 0.8 nM), dogs with hypoplastic testicles (0.8 +/- 0.9 nM) and dogs with one degenerated and one retained testis or with bilateral cryptorchidism (1.2 +/- 0.9 nM) compared to dogs with one or two normal testes (7.0 +/- 5.5 nM). Testicular volume and weight were significantly lower in degenerated, hypoplastic and retained testes compared with the contralateral normal testis. Some spermatogenic activity was found in three of the retained testes, producing oligozoospermic smears with a high percentage of sperm abnormalities. No comparable epidemiological data about male pathological conditions of the reproductive organs in the dog is available. The prevalence found in this study, yet, appears high.     

Cyanide intoxication in sheep: enhancement of efficacy of sodium nitrite, sodium thiosulfate, and cobaltous chloride.

For treatment of cyanide intoxication of ruminants, the present recommended doses of sodium nitrite (5 mg/kg of body weight) and sodium thiosulfate (25 to 50 mg/kg) are smaller than those recommended for other animals; the decrease is partially attributed to the greater susceptibility of ruminants to the toxic effects of sodium nitrite. Based on the high tissue concentration and activity rate of rhodanese in ruminants, sulfur donors such as sodium thiosulfate could be utilized more efficaciously. Doses of sodium nitrite and sodium thiosulfate (up to 22 and 660 mg/kg, respectively) were evaluated in the present studies. Adjustment of the antidotal combination provided almost three times the protection afforded by the previously recommended doses. Moreover, under the conditions tested, the newly adjusted dose levels of sodium thiosulfate alone were more effective than the previously used antidotal combination of sodium nitrite and sodium thiosulfate and this protective effect was enhanced by cobaltous chloride (10.6 mg/kg) or sodium nitrite. The present recommended therapeutic approach to cyanide intoxication in sheep should be based primarily on administration of a much higher dose of sodium thiosulfate in combination with sodium nitrite or cobaltous chloride (or both).     

Perineal hernia in the dog

The case records and owners of seventy–two dogs with perineal hernia seen at the University of Pennsylvania Veterinary Hospital were surveyed. The condition was seen in older male dogs, most of which presented with perineal swelling and straining to defaecate. Most dogs were treated by perineal herniorrhaphy. The incidence of recurrence in those dogs treated surgically was 46%. Recurrence was more common when the surgery had been performed by inexperienced surgeons, in those dogs which had been treated surgically elsewhere, and in those dogs in which the time period from surgery to survey was more than 1 year. Other complications occurring were wound infection, faecalincontinence, urinary problems and lameness. Most owners of dogs which were alive at the time of the survey were satisfied with the results of treatment. Castration had no effect on the incidence of recurrence or development of a hernia on the opposite side to that repaired initially. Résumé. On a étudié les dossiers de soixante-douze chiens avec des nernies perinéales, vus à l'Hǒpital vétérinaire de l'Université de Pennsylvanie. On a observé la condition chez des chiens mǎles plus ǎgés dont la plupart souffraient d'enflure périnéale et devaient faire tous leurs efforts pour aller à la selle. La plupart des chiens ont été traités par suture de hernie périnéale. Le taux de récidive chez ces chiens traités par chirurgie, a été de 46%. Les récidives ont été plus communes quand la chirurgie a été pratiquée par des chirurgiens peu expérimentés, chez ces chiens traités par chirurgie ailleurs, et chez ceux pour lesauels le laps de temps d'une opération à une autre était de plus d'un an. Une infection de la plaie, une incontinence de fèces, des problèmes urinaires et un état de claudication se comptent parmi les complications survenues. La plupart des propriétaires dont les chiens étaient vivants au moment de cette étude ont été satisfaits des résultats. La castration n'a pas eu d'effet sur la récidive ou le développement d'une hernie du cǒté opposé de celle qui avait été réparée auparavant. Zusammenfassung. Eine Aufzeichnung von Fàllen mit perinealer Hernie in 72 Hunden, die man im Tierǎrztlichen Krankenhaus der Universitǎt von Pennsylvanien sah, wurde iiberblickt. Man fand den Zustand in àlteren mànnlichen Hunden, von denen die meisten périnéale Sch-wellung und Anstrengung beim Dafàzieren zeigten. Die neisten Hunde wurden durch périnéale Bruchnaht behandelt. Der Vorfall von erneutem Auftreten dieser Beschwerden in jenen Hunden die chirurgisch behandelt wurden, war 46%. Emeutes Auftreten war hàufiger, wenn die Opération von unerfahrenen Ghirurgen ausgefùhrt wurde, in den Hunden die anderswo chirurgisch behandelt waren und in Jenen Hunden, deren Zeitspanne von einer Opération zur anderen mehr als ein Jahr betrug. Andere Komplikationen die vorkamen ware Wundinfektion, Nichthalten-kǒnnen des Kotes, urinàre Problème und Lahmheit. Die meisten Besitzer der Hunde die zur Zeit des Uberlicks am Leben waren, zeigten sich mit dem Ergebnis der Behandlung zufrieden.