A Far-Field Hydrothermal Plume from Loihi Seamount

An extensive helium plume in the north central Pacific emanates from Loihi Seamount on the flanks of Hawaii. The maximum helium signal is found at a depth of about 1100 meters, the same depth as the near-field plume directly above Loihi Seamount. Although this helium plume is strongest near Hawaii, where the 3He/4He ratio at a depth of about 1100 meters reaches values 28 percent above the atmospheric ratio, it can be detected quite clearly at latitude 24°N, over 400 kilometers to the north. Excess 3He is also present on the same isopycnal between 15°N and 20°N at 135°W, some 2000 kilometers east of the Hawaiian Islands.     

Vertical Flux of Biogenic Carbon in the Ocean: Is There Food Web Control?

Models of biogenic carbon (BC) flux assume that short herbivorous food chains lead to high export, whereas complex microbial or omnivorous food webs lead to recycling and low export, and that export of BC from the euphotic zone equals new production (NP). In the Gulf of St. Lawrence, particulate organic carbon fluxes were similar during the spring phytoplankton bloom, when herbivory dominated, and during nonbloom conditions, when microbial and omnivorous food webs dominated. In contrast, NP was 1.2 to 161 times greater during the bloom than after it. Thus, neither food web structure nor NP can predict the magnitude or patterns of BC export, particularly on time scales over which the ocean is in nonequilibrium conditions.     

Simultaneous Measurement of Local Gain and Electron Density in X-ray Lasers

X-ray lasers (XRLs) have experimental average gains that are significantly less than calculated values and a persistently low level of spatial coherence. An XRL has been used both as an injected signal to a short XRL amplifier and as an interferometer beam to measure two-dimensional local gain and density profiles of the XRL plasma with a resolution near 1 micrometer. The measured local gain is in agreement with atomic models but is unexpectedly spatially inhomogeneous. This inhomogeneity is responsible for the low level of spatial coherence observed and helps explain the disparity between observed and simulated gains.     

Dopaminergic and Opioidergic Regulation of Gonadotropin and Prolactin Release in Stallions

In the non‐breeding season, LH release is reduced via dopaminergic systems in the ram. On the other hand, our previous studies demonstrated an opioidergic inhibition of LH release in stallions outside the breeding season. Thus, in the present study we investigated the dopaminergic regulation of LH and prolactin secretion in stallions, considering interactions between dopamine and opioids. To achieve this, stallions (n=8) were treated with the dopamine antagonist sulpiride (0.6 mg/kg), the opioid antagonist naloxone (0.5 mg/kg), sulpiride plus naloxone or saline in December, March and June. Two hours after the respective treatments, they received a GnRH agonist. Sulpiride induced a significant prolactin release which was most pronounced in December, indicating seasonal variations in the inhibition of prolactin secretion by dopaminergic systems. Prolactin concentrations were not changed by naloxone. Neither during nor outside the breeding season, a dopaminergic regulation of LH release could be demonstrated. In contrast, naloxone caused a significant (p < 0.05) LH release, confirming an opioidergic inhibition of LH release. In conclusion, opioidergic regulation of LH and dopaminergic inhibition of prolactin secretion undergo seasonal changes. Neither during nor outside the breeding season, dopaminergic effects on LH release exist in the stallion.     

Expression of Genes Associated with Apoptosis in the Porcine Corpus Luteum During the Oestrous Cycle

The corpus luteum (CL) of the pig lacks luteolytic sensitivity (LS) to prostaglandin (PG) F‐2α until after day 12 of the oestrous cycle, but the mechanisms underlying this phenomenon are poorly understood. As luteolysis involves apoptosis, we hypothesized that critical apoptotic proteins may be deficient in CLs that lack LS. The specific aim of these studies was to examine mRNA expression and protein levels of apoptosis genes/proteins (BAX/Bax, BCLX/Bcl‐x, CASP3/Caspase‐3, CASP8/Caspase‐8, NFΚB1/NFκB, TP53/p53) in porcine CLs collected at different stages of the oestrous cycle. CLs were collected surgically, mRNA and protein extracted, and expression/levels analyzed by semi‐quantitative (SQ) PCR and Western blots, respectively. At the mRNA expression level, only BAX (maximal on day 4) and TP53 (maximal on day 7) showed significant variations during the oestrous cycle. At the protein level, only Bcl‐x and Caspase‐3 showed significant changes during the cycle; Bcl‐x decreased on day 13 and Caspase‐3 increased on day 13. It is concluded that apoptosis‐associated proteins (i.e. Bcl‐x and Caspase 3) may play a critical role in luteolytic sensitivity in the pig.     

Meningoencephalitis and other conditions associated with Histophilus ovis infection in sheep

Histophilus ovis was isolated from 29 sheep in 20 flocks and 2 artificial insemination (AI) centres in southern New South Wales from 1984 to 1990. The clinical and pathological findings were consistent with previous reports and included polyarthritis (7 flocks), epididymo-orchitis (5), meningoencephalitis (3), pneumonia (3), septicaemia (2), mastitis (1) and metritis (1). Six sheep had meningoencephalitis, a syndrome not previously associated with H ovis infection in sheep, which was similar pathologically to thromboembolic meningoencephalitis in cattle, caused by the related organism, Haemophilus somnus. H ovis was isolated from the semen of 12-month-old rams in a flock that had polyarthritis due to H ovis, in 4-month-old ram lambs and from the uterus of a ewe in a flock that had sporadic cases of H ovis septicaemia.     

Adverse Drug Reactions: Report of the Australian Veterinary Association Adverse Drug Reaction Subcommittee, 1993

SUMMARY Fifty-nine reports of suspected adverse drug reactions (ADRs) were received by the Adverse Drug Reaction Subcommittee of the Australian Veterinary Association from April 1992–March 1993 inclusive. The number of reports received/number of animals involved per species was: dogs (30/43); cats (11/14); horses (8/10); cattle (9/30); ferret (1/1). Of these, 37 (63%) were classified as definite ADRs and 12 (20%) as probable ADRs. In 10 (17%) reports an ADR could not be substantiated or there was insufficient information available to make a decision. Twenty-three reports involved apparent hypersensitivity reactions and 5 reports were associated with ‘off-label’ use. Of the definite and probable reports of suspect ADRs the most frequent types of drugs involved were antimicrobials (9 reports), anthelmintics (9 reports), vaccines (7 reports), insecticides (6 reports), vitamin preparations (6 reports), topical anti-inflammatory/antimicrobial/antifungal skin preparations (3 reports) and nonsteroidal anti-inflammatory preparations (3 reports). Single reports concerning definite or probable ADRs to an anticholinergic, an anaesthetic agent, a corticosteroid, an anabolic steroid and a chondroprotective drug were received.     

OC5Filtration Thought Sephadex Columns Does not Alter the Subpopulation Characteristics in Fresh Boar Semen

The aim of this study was to analyse the effect of filtration through Sephadex on the subpopulation characteristics of the boar semen. For this purpose 3 ml of 16 commercial doses of fresh diluted boar semen were filtered through a Sephadex G‐15/Polypropylene column. Motility parameters were analysed by a CASA system and statistical study was performed by SAS package using the VARCLUS and the FASTLUST procedures. Statistical study revealed four subpopulations in fresh boar semen, as previously had described (Theriogenology 61: 673–690).Total motility was higher in control than in filtered semen, but there were not statistical differences (65.63 ± 9.65 vs 41.40 ± 9.02). Moreover, the analysis did not show many changes neither in the characteristics nor in the distribution of the four subpopulations. As example although ALHmed of filtered samples were slightly higher, there were only significant differences (p < 0.001) in two subpopulations (subpopulation 2 : 2.2 ± 0.05 in control vs 2.7 ± 0.08 in filtered. Subpopulation 3 : 4.5 ± 0.11 in control vs 5.8 ± 0.23 in filtered semen). HME was also statistically different (p < 0.005) in one subpopulation, showing great values in filtered semen (1.7 ± 0.15 vs 3.0 ± 0.30). In conclusion, the filtration by Sephadex/Polypropylene column does not cause strong changes in subpopulation sperm distribution.     

Blindness in goats following ingestion of Stypandra glauca

Twenty-seven of 427 Angora goats of mixed age became blind within a week of consuming large amounts of Stypandra glauca ("nodding blue lily"). A further 200 goats were depressed for several weeks, but most subsequently recovered. Blindness was associated with optic nerve neuropathy which is postulated to have followed compression of the optic nerves within the bony optic canals as a result of severe myelin oedema. Histologically, the intracanalicular portion of the optic nerve was sclerotic, while the intracranial portion of the optic nerve and the optic tracts were degenerating. The retrobulbar portion of the optic nerve was relatively unaffected. In addition, multifocal retinal photoreceptor degeneration was found ophthalmoscopically and histologically. The syndrome was not reproduced during a trial in which 2 goats were fed 4 and 20 kg of S. glauca harvested after it had finished flowering, more than 3 weeks after the first natural cases of blindness. Based on epidemiological and pathological data we propose that S. glauca is toxic to stock, but only for a short period while flowering in spring.