Gastric cancer originating from bone marrow-derived cells

Epithelial cancers are believed to originate from transformation of tissue stem cells. However, bone marrow-derived cells (BMDCs), which are frequently recruited to sites of tissue injury and inflammation, might also represent a potential source of malignancy. We show that although acute injury, acute inflammation, or transient parietal cell loss within the stomach do not lead to BMDC recruitment, chronic infection of C57BL/6 mice with Helicobacter, a known carcinogen, induces repopulation of the stomach with BMDCs. Subsequently, these cells progress through metaplasia and dysplasia to intraepithelial cancer. These findings suggest that epithelial cancers can originate from marrow-derived sources and thus have broad implications for the multistep model of cancer progression.     

Metastatic hibernomas in transgenic mice expressing an alpha-amylase-SV40 T antigen hybrid gene

Mice transgenic for a hybrid gene containing the liver promoter of the mouse amylase gene (Amy-1a) fused to the SV40 tumor antigen coding region unexpected developed malignant brown adipose tissue tumors (malignant hibernomas). Expression of the alpha-amylase gene had previously been thought to be confined to the liver parotid, and pancreas; however, analysis of white and brown adipose tissue from nontransgenic mice revealed expression of the endogenous Amy-1a gene in these tissues. Gene constructs driven by the Amy-1a liver promoter thus provide a means of targeting gene expression to the adipocyte cell lineage in transgenic mice. Moreover the high frequency of metastases in the liver, lungs, spleen, heart, and adrenals of these mice provides an experimental system in which to study the development of disseminated malignancy.     

Platy Quartz Phytoliths found in the Fossil Forest Deposits,Axel Heiberg Island,Northwest Territories,Canada

The occurrence of quartz particles having a platy morphology found in the white layers within the fossil forest deposits of Axel Heiberg Island, was further confirmed by optical and electron microscopic examinations. The platy quartz crystals were concentrated in the finer fractions. The δ ₁₈O values of fractions enriched in platy quartz crystals ranged from +13.7 to +16.6 %₀. These values were higher than those obtained for coarser fractions. The platy morphology and crystallographic character of the quartz particles concentrated in the finer size fractions are uncharacteristic both of aerosol derived material and of secondary silica. These findings and information available for the paleoenvironment of the study area favor a biogenic origin for the platy quartz. The oxygen-isotope data are consistent with this hypothesis.     

Sulphur speciation and turnover in soils: evidence from sulphur K-edge XANES spectroscopy and isotope dilution studies

Sulphur K-edge X-ray absorption near edge structure (XANES) spectroscopy was used to quantify S species in humic substance extracts from ten soils from the UK, China and New Zealand, which differ in land use and agricultural management. XANES spectroscopy showed the presence of most reduced (sulphides, disulphides, thiols and thiophenes), intermediate (sulphoxides and sulphonates) and highly oxidised S (ester sulphates) forms, with the three groups representing 14-32%, 33-50% and 22-53% of the organic S in the humic substance extracts, respectively. Land use had a profound influence on the relative proportions of S species. Well-drained arable soils generally had a higher proportion of organic S present in the most oxidised form than the grassland soils collected nearby, whereas paddy soils showed a more reduced profile due to episodic flooding. In the Broadbalk Classical Experiment at Rothamsted, reversion of an arable system to grassland or woodland in the 1880s resulted in an increase of the most reduced and intermediate S species at the expense of the most oxidised S species. Long-term applications of farmyard manure to an arable plot also shifted S species from the most oxidised to the intermediate and the most reduced species. Sulphur immobilisation and gross mineralisation were determined in seven soils using the ³⁵S isotope dilution method. Gross mineralisation during a 53-day incubation correlated more closely with the amounts of the most reduced and intermediate S species than with the most oxidised S species, suggesting that the former (C-bonded S) were the main source of organic S for mineralisation in the short-term.     

Long-term anaesthesia with propofol and alfentanil in the dog and its partial reversal with nalbuphine

Prolonged surgical anaesthesia in the dog was induced with propofol (6.5 ± 1.3 mg/kg) followed by alfentanil (25.5 ± 5 μg/kg) (mean ± 1 sd) and maintained with a continuous infusion of propofol (0.14 to 0.18 mg/kg/min) and alfentanil (2 to 3 μg/kg/min). Neuromuscular blockade was produced with vecuronium (0.1 mg/kg). After induction of anaesthesia with propofol, administration of alfentanil to dogs which had received no pre-anaesthetic medication produced cardiac arrest and apnoea. Administration of atropine intravenously immediately prior to alfentanil prevented these cardiac depressant effects. The cardiac depressant effect of alfentanil was not as severe in a second group of dogs in which anaesthesia was induced with thiopentone. After commencing the continuous infusion anaesthetic regime and establishment of IPPV, blood pressure and heart rate remained stable during the remaining 4 to 6 h period of anaesthesia. Recovery from anaesthesia was smooth and uneventful. The depressant effects of alfentanil on respiration and on consciousness were reversed rapidly by administration of nalbuphine (10 mg total dose). The smooth recovery and the integration of anaesthesia and post operative analgesia attained by the reversal of alfentanil with nalbuphine make this an attractive anaesthetic regime for major surgery in dogs, provided that facilities for IPPV are available.     

Techniques and complications of pacemaker implantation in four cats.

Pacemakers were successfully implanted in 4 adult and geriatric cats with bradycardia and associated signs. Various implantation techniques were used. Complications developed in 3 of the cats, generally more severe in 2 of the 3 cats in which thoracotomy and celiotomy were performed than in the cat in which a transvenous endocardial pacing technique was used. After surgery, pacemaker functions were reprogrammed noninvasively in 2 cats. All 4 cats survived without syncope for a mean of 33.1 months after surgery.     

BUDGET ANALYSIS OF PENAEID SHRIMP HATCHERY FACILITIES

One of the critical factors in commercial penaeid shrimp culture production is the availability of postlarvae to stock grow-out ponds. This study investigates the economic feasibility of rearing penaeid shrimp from nauplii to postlarvae (hatchery phase). The facility design used is based on the hatchery operated by Texas A&M university at Galveston, Texas. The Generalized Budget Simulation Model for Aquaculture developed at Texas A&M University was used for the analysis. A ten-year planning horizon was used for the analysis. Six different systems ranging in size from 5 ten-metric ton tanks to 60 ten-metric ton tanks were examined. Annual cost and return budgets were developed for the six systems assuming they operated 6 and 12 months per year. Investment costs, break-even prices and quantities, and net present value were estimated for each system. Results show that commercial hatcheries, using 10-metric ton tanks, could be profitable above and including 20 tanks for those operating only six months annually and above and including 10 tanks for those operating 12 months annually.     

Alteration of neutrophil function associated with coccidiosis in cattle: influence of decoquinate and dexamethasone

Twenty Holstein steers subclinically infected with coccidia were allotted to 2 groups of 10 steers each. One group received a diet containing 0.5 mg of decoquinate/kg of body weight. After 25 days on the diet, there was no difference between the groups in lymphocyte blastogenic responsiveness to mitogens; however, there were differences in neutrophil function. Lymphocytes from steers of the decoquinate-fed group had decreased random migration under agarose, enhanced cytochrome C reduction, and enhanced iodination activity. Other measures of neutrophil function evaluated (chemotactic index, Staphylococcus aureus ingestion, and antibody-dependent and -independent cell-mediated cytotoxicity) were not affected. After 30 days of decoquinate feeding, half of the cattle in each group received 5 daily IM injections of dexamethasone (0.04 mg/kg of body weight). The dexamethasone-treated steers from the group that did not have decoquinate in the diet developed clinical coccidiosis, whereas the decoquinate-treated steers remained clinically normal. Lymphocyte and neutrophil function were again evaluated for a 3-day period beginning 4 days after dexamethasone treatment was halted. Neutrophils from the steers that developed clinical coccidiosis after dexamethasone administration had significantly (P less than 0.05) inhibited random migration under agarose, cytochrome C reduction, and iodination activity, but significantly (P less than 0.01) enhanced S aureus ingestion. The feeding of decoquinate prevented the inhibition of neutrophil cytochrome C reduction and lessened the inhibition of neutrophil iodination in the dexamethasone-treated group. Dexamethasone treatment was associated with an inhibition of lymphocyte blastogenic responsiveness to phytohemagglutinin in principals as well as controls.