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Biomedical subjects

J M Jones

Publications and source records attributed to J M Jones.

At least 343 records · Page 19Linked to original sources
PubMed1966

The biological activity of subfragment 1 prepared from heavy meromyosin.

1. The action of trypsin, chymotrypsin and subtilisin on the adenosine-triphosphatase and actin-combining activities, as measured by viscometric means, of H-meromyosin were compared. 2. Subfragment 1 produced by prolonged tryptic digestion has a molecular weight of 129000. 3. The preparations isolated by gel filtration and actin combination were shown to be similar. 4. Subfragment-1 preparations possess appreciably higher adenosine-triphosphatase activities than H-meromyosin when related to total nitrogen. 5. Chromatographic and gelfiltration studies indicated that adenosine-triphosphatase activity is not distributed uniformly in all fractions of subfragment 1. 6. The Ca(2+)-activated adenosine triphosphatase of subfragment 1 was stimulated by thiol reagents in a similar fashion to myosin and H-meromyosin. 7. Subfragment 1 differed from myosin and H-meromyosin in that its adenosine triphosphatase was only slightly activated by Mg(2+) in the presence of actin. 8. A subfragment-1-like component was obtained by chymotryptic digestion of H-meromyosin. 9. The results obtained from enzymic and hydrodynamic studies and from amino acid analyses are compatible with the concept of one molecule of H-meromyosin giving rise to one molecule of subfragment 1 on proteolytic digestion.

Adenosine Triphosphatases↗
PubMedDate not supplied

Surgical treatment of early-stage carcinoma of the oral tongue--wound adjuvant treatment be beneficial?

A group of 97 patients with clinical stage I and stage II squamous carcinoma of the oral tongue, treated by partial glossectomy alone, has been reviewed to define prognostic indicators. Sixty-seven patients were staged T1N0 and 30 were T2N0. Disease recurred in 28 patients (27%) and the most common site of failure was the ipsilateral neck (21%). The incidence of initial recurrence did not vary significantly with patient age, sex, T-stage, or when tumor size was examined in other subdivisions. The presence of perineural invasion significantly increased recurrence rate (P = 0.003) and decreased survival (P = 0.002). Disease-free survival at 5 yr was 73% for patients with T1 tumors, and 62% for T2 tumors. This difference was not significant. In this low-risk patient population with early stage carcinoma of the oral tongue, partial glossectomy is adequate treatment in most cases. However, we recommend postoperative radiation therapy to the primary site and ipsilateral neck for patients with perineural invasion. No evidence could be found to support adjuvant local therapy or elective neck treatment in the remaining patients.

Adult↗
PubMedDate not supplied

Hypnic headache: another indomethacin-responsive headache syndrome?

Hypnic headache syndrome is a benign, recurrent, late-onset headache disorder that occurs exclusively during sleep. Lithium has been reported to be an effective treatment, but the side effects of this medication are sometimes prohibitive, particularly in the elderly. Other drugs have been reported to be effective in this disorder, including caffeine, flunarizine, and verapamil. Recently, indomethacin has been reported to effectively suppress hypnic headaches. We report the response of seven patients with hypnic headache who were treated with indomethacin. Hypnic headache syndrome appears to represent yet another headache disorder in which there is sometimes an impressive response to indomethacin.

Aged↗
PubMedDate not supplied

Organophosphorus poisoning in two Rex rabbits.

A case of organophosphorus (OP) poisoning in two Rex rabbits is described. Three animals were diagnosed as having dermatitis characterised by pruritus and alopecia due to infestation with Cheyletiella parasitivorax. Two of the animals were dipped in 2% malathion solution: one died within 15 hours post-dipping, the other was euthanased subsequent to the onset of convulsions. A procedure for the future dipping of rabbits is suggested, and a recommendation is made for a lower concentration of malathion to be used.

Journal Article↗
PubMedDate not supplied

Effects of hypervolemia and hypovolemia on cardiac and posterior lymph heart function in the toad Bufo marinus (L.).

Cardiac and posterior lymph heart function in the toad Bufo marinus (L.) were measured in response to hemorrhage and both systemic and lymphatic volume loading to evaluate the role of the amphibian lymphatic system in fluid regulation. In every animal, systemic volume loading elicited an initial sharp rise in mean arterial blood pressure, corresponding to an immediate cessation of lymph heart contraction lasting approximately 12 min. This was followed by a short-term decrease in blood pressure, to 36% below normal. While stroke volume and lymph flow for the individual animals increased variably over a 6-h period, mean lymph heart rate and pressure varied little. Lymphatic volume loading elicited only minor changes in blood heart and lymph heart rate. Again, stroke volume and lymph flow increased variably, with the effect lasting about 13 h. Hypovolemia caused a sharp drop in blood pressure and a corresponding rise in blood heart rate. Lymph heart variables changed little, with the exception of rate, which, in some animals, was elevated for approximately 20 min following hemorrhage.

Animals↗
PubMedDate not supplied

Guidelines for evaluating tools for clinical decision making.

Managed care is designed to reduce healthcare costs by controlling use of services and by improving quality outcomes. Preparation of nurses to practice in a health management environment mandates clear understanding of this new environment Nursing educators should focus on the spectrum of health services and enhance the nurses'ability to assess patients independently, implement health plans, and be responsible for outcomes. Nurses must understand how clinical decision-making tools facilitate planning care to maximize use of resources. The authors describe the construction and evaluation of a learning strategy that involves the use of guidelines to evaluate clinical decision-making tools. Two examples are presented: evaluating clinical pathways in a case management project and evaluating algorithm (practice guideline) outcome data from a prenatal population case study from a local health maintenance organization.

Algorithms↗
PubMedDate not supplied

Acidification of intracellular pH in bovine spermatozoa suppresses motility and extends viable life.

Intracellular pH (pHi) was determined in ejaculated bovine spermatozoa using a ratiometric absorbance technique under various incubation conditions that drastically altered sperm motility. The pHi was directly correlated with sperm motility. In a medium of Sodium, Potassium, and Magnesium [NKM] that supported active sperm motility, pHi was 6.9. In medium containing weak acids (NKM equilibrated with 100% CO2 or containing 80 mM 5,5-dimethyl-2,4-oxazolidinedione; DMO), pHi was depressed at least 0.5 pH unit and sperm motility was suppressed. After complete immobilization of sperm was established, removal of the weak acids indicated that suppression of motility was fully reversible for up to 48 hours in CO2 and up to 24 hours in DMO. This study shows that expression and conservation of sperm motility are inversely related, and that depression of pHi by weak acids can reversibly inhibit sperm motility. These findings may help to explain the mechanisms by which sperm are immobilized within the male reproductive tract, and could be applicable to the design of improved ambient temperature semen extenders.

Acids↗