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Biomedical subjects

J McReynolds

Publications and source records attributed to J McReynolds.

12 recordsLinked to original sources
PubMed2005

Evaluation of Salmonella enteritidis in molting hens after administration of an experimental chlorate product (for nine days) in the drinking water and feeding an alfalfa molt diet.

The method most commonly used to induce molting and stimulate multiple egg-laying cycles in laying hens for commercial egg production is to fast the hens. Unfortunately, increased risk of Salmonella enteritidis (SE) infection may result from the use of this method. Methods to stimulate multiple egg-laying cycles without increasing the risk of SE infection are needed. Hens over 50 wk of age were divided into 12 groups of 11 hens each and placed in individual laying cages. One week prior to dietary changes, hens were placed on an 8-h light and 16-h dark photoperiod that continued for the 9-d molt. All hens were challenged orally with 10(6) cfu of SE on the fourth day of the molt. Treatments were nonfed hens with distilled water (NFD), nonfed hens with the experimental chlorate product (ECP, which provided 15 mM chlorate ion) water (NFECP), alfalfa diets with distilled water (ALD), and alfalfa diets with ECP water (ALECP). In the NFD hens, 67% (log10 2.74) of the crops and 94% (log10 5.62) of the ceca were colonized, whereas for the NFECP hens significant reductions to 22% (log10 1.05) of the crops and 61% (log10 2.44) of the ceca were observed. In the ALD hens, 61% (log10 2.52) of the crops and 94% (log10 4.06) of the ceca were colonized. In the ALECP hens, highly significant reductions to 11% (log10 1.26) of the crops and 39% (log10 1.12) of the ceca were observed. When compared with the NFD hens, significant reductions in SE invasion of the ovary, liver, and spleen occurred in all other treatments, except the ovary in the ALD hens. The low alfalfa intake is probably a factor in our lowered protection against SE when compared with previous results. For several parameters, these results suggest that ECP or the combination of ECP and alfalfa may be a useful tool to reduce the risk of SE during an induced molt.

Animal Feed↗
PubMed1999

The bovine mimecan gene. Molecular cloning and characterization of two major RNA transcripts generated by alternative use of two splice acceptor sites in the third exon.

Mimecan is a proteoglycan expressed by many connective tissues. It was originally isolated in a truncated form as a bone-associated glycoprotein, osteoglycin, and was considered an osteoinductive factor. Recently, we demonstrated that the full-length translation product of the cDNA encoding mimecan is a corneal keratan sulfate proteoglycan present in other tissues without keratan sulfate chains. We also described multiple mimecan mRNA transcripts generated by differential splicing and alternative polyadenylation. In this study, we isolated genomic clones and determined the genomic organization of the bovine mimecan gene. The gene is spread over >33 kilobases of continuous DNA sequence and contains eight exons. The newly discovered first exon, identified by 5'-rapid amplification of cDNA ends, consists of a 5'-untranslated region and is enriched in C+G nucleotides. Two transcription initiation sites starting at the first and at the second exons were determined by primer extension. Molecular characterization shows that alternatively spliced RNA isoforms are generated by the use of two distinct splice acceptor sites in the third exon situated 278 base pairs apart. We determined a partial genomic structure of the human mimecan gene and demonstrated two alternatively spliced RNA transcripts that are generated likewise. Despite the diversity of mimecan transcripts, the primary structure of the core protein is encoded from exons 3 to 8 and remains unchanged, indicating its functional importance. Using ribonuclease protection assay, we analyzed the patterns of spliced RNA expressed in cultured bovine keratocytes. We demonstrated that their expression is differentially modulated in a temporal manner by basic fibroblast growth factor.

Aged↗
PubMed1991

Short-term potentiation of off-responses in turtle horizontal cells.

Depolarizing responses to light off were studied in turtle horizontal cells using intracellular recording in the everted eyecup preparation. In many cells the off-response showed two components (fast and slow) which could overshoot beyond the steady-state dark level. The peak amplitudes of the fast and slow components increased with increasing duration of the light stimulus. A similar enhancement of the off-responses could also be produced by repetitive stimulation with brief flashes. However, the degree of enhancement produced by repetitive stimulation was greater than could be produced by increasing stimulus duration, and the latency of the onset of depolarization was longer, suggesting that the enhancement produced by repetitive stimulation involves an additional mechanism. Dramatic enhancement of the off-response by stimuli which did not affect the on-response during light indicates that the off-response may contain information not present in the on-response. The fast component of the off-response was suppressed to a greater degree than other components by reducing extracellular calcium or in the presence of 500 microM cobalt, suggesting that this component may involve a calcium current.

Animals↗
PubMed1991

Effect of vanadate on renal hypertrophy and sorbitol accumulation in streptozotocin induced diabetes in rats.

Vanadate has been previously shown to normalize blood glucose in streptozotocin-induced diabetic (STZ-DM) rats. The effect of a previously studied dose of vanadate (0.8 mg/ml) in drinking water on blood glucose, renal hypertrophy, and whole kidney polyol accumulation was studied in STZ-DM rats. Rats with diabetes of 5 weeks duration had higher blood glucose, greater urinary output, higher kidney weight, lower body weight, and higher kidney to body weight ratios than controls. Whole kidney sorbitol concentrations were significantly increased in diabetes but myo-inositol levels were unchanged vs control animals. After four weeks of oral vanadate treatment, blood glucose, urine volume, and kidney weights were similar to control values. Kidney to body weight ratios fell below that of the STZ-DM animals, but because body weights remained decreased, the kidney to body weight ratios were not normalized. Renal sorbitol levels returned to control values and renal myo-inositol levels remained unchanged in STZ-DM and normal animals treated with vanadate. These results provide evidence that vanadate therapy may result in regression of the hypertrophy and polyol accumulation characteristic of diabetic nephropathy in STZ-DM rats. This effect is most likely due to normalization of blood glucose by the insulin-mimetic activity of vanadate treatment.

Animals↗
PubMed1988

Effect of acute and chronic hypernatremia on myoinositol and sorbitol concentration in rat brain and kidney.

In animal models of hypernatremia, increases in brain electrolyte content account for the entire increase in osmolality in acute but not chronic hypernatremia, suggesting that there is generation of additional intracellular solutes ("idiogenic osmoles") in chronic hypernatremic states. In the present study, the concentration of the polyols myoinositol and sorbitol and water content were determined in the brain and kidneys of rats made acutely (2 hours) and chronically (72 hours) hypernatremic by intraperitoneal injection of NaCl and water restriction. Both the brain and the kidney responded to chronic hypernatremia with increased levels of myoinositol. Sorbitol levels increased in the kidney in response to both acute and chronic hypernatremia. Water content dropped in acute hypernatremia, but remained unchanged during chronic hyperosmolar challenge. We conclude that the polyols, myoinositol and sorbitol, may play a significant role in cellular osmoregulation in brain and kidney during chronic hypernatremia in the rat.

Acute Disease↗
PubMed1987

Radiation chemistry of 2'-deoxycytidylyl-(3'-5')-2'-deoxyguanosine and its sequence isomer in N2O- and O2-saturated solutions.

The radiation chemistry of the dinucleoside monophosphate d(CpG) and its sequence isomer, d(GpC), has been examined in aqueous solutions saturated with either N2O or O2. The products were isolated using HPLC, and the major products were identified using proton NMR spectroscopy and mass spectrometry. The major products include 5,6-dihydroxy-5,6-dihydrouracil (glycol) derivatives, 5- and 6-hydroxycytosine substitution products, 1-carbamoyl-2-oxo-4,5-dihydroxyimidazolidine products, and the 8-hydroxyguanine substitution product. Both trans stereoisomers of the imidazolidine derivatives are obtained from d(CpG) as well as from its sequence isomer. These are prominent products when the irradiation is carried out in the presence of oxygen, but they are not observed in the absence of oxygen.

Deoxycytidine↗
PubMed1980

Diagnosis of viral infections by multicomponent mass spectrometric analysis.

Metabolic profiles of urine extracts of humans with viral infections, as well as of media of virus-infected human tissue cultures, have been analyzed by non-fragmenting mass spectrometry and compared with corresponding controls. The spectra were then subjected to several alternative computerized statistical procedures to detect diagnostic biochemical profiles. Controlled longitudinal studies on fully informed, consenting volunteers who received sandfly fever virus demonstrate the onset of a characteristic metabolic pattern that precedes the onset of symptoms and subsides when the patients overcome the infection. Longitudinal studies of human tissue cultures infected with poliomyelitis virus demonstrate characteristic metabolic patterns within a few hours after infection. Non-fragmenting mass spectrometry may thus provide the clinical laboratory with a sensitive, reliable test for viral infections significantly faster than attainable by current techniques.

Bunyaviridae↗
PubMed1977

Acute copper intoxication. Pathophysiology and therapy with a case report.

We report a case of cupric sulfate intoxication in a child who had a serum copper level of 1,650 mug/100 ml. His course was accompanied by hemolytic anemia and renal tubular damage. We review the pathophysiology of copper metabolism and intoxication. We also review modes of therapy, with specific reference to the initial approach, using dimercaprol (BAL) and edetic acid rather than penicillamine.

Acute Disease↗
PubMedDate not supplied

The New York Angler Cohort Study: exposure characterization and reproductive and developmental health.

The New York State Angler Study will evaluate the association between past and current consumption of contaminated fish from Lake Ontario and both short- and long-term health effects in a population-based cohort. It will measure fish consumption and reproductive and developmental health among 10,518 male anglers and 6,651 of their wives or partners, as well as among 913 female anglers. To characterize exposure among subgroups of the cohort, further analytical methods were developed and implemented to measure specific polychlorinated biphenyls (PCB) congeners, methylmercury, and other substances in biological samples. Exposure assessment has been completed for a stratified random sample of 321 anglers. In addition, analyses for 79 congeners of PCBs are complete for 177 anglers. A special study of duck and turtle consumers currently is underway. Telephone interviews have been completed with 2,454 of the 2,999 women who planned a pregnancy between 1991 and 1994. The entire cohort of male anglers, partners of male anglers, and female anglers has been submitted for matching with the New York State live birth and fetal death registries to obtain lifetime reproductive histories. A medical record abstraction study will assess perinatal and developmental outcomes among the 3,442 births that occurred between 1986 and 1991. Finally, a study of breast milk from currently lactating women is underway, and 215 breast milk samples have been collected from the planned pregnancy subcohort. Progress on each of the study components is discussed herein.

Animals↗