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Biomedical subjects

L A Jones

Publications and source records attributed to L A Jones.

At least 163 records · Page 9Linked to original sources
PubMed1986

Obesity, non-protein-bound estradiol levels, and distribution of estradiol in the sera of breast cancer patients.

This study attempted to determine the relationship of nutritional status, menopausal status, presence of breast cancer, stage of disease, and tumor estrogen receptor levels to percent non-protein-bound estradiol (%NPBE) and percent distribution of estradiol on sex hormone-binding globulin (SHBG) and albumin in breast cancer patients and control patients. Normal-weight controls had significantly lower %NPBE compared with overweight controls and normal-weight and overweight breast cancer patients. There was a significant shift in the percent distribution of estradiol from SHBG to albumin in breast cancer patients, independent of body weight. Elevated %NPBE and abnormal percent estradiol distribution on albumin persisted after mastectomy and were unrelated to menopausal status, presence and stage of disease, and tumor estrogen receptor levels. These results show that breast cancer patients have increased exposure to unbound circulating estradiol and an increased percentage of estradiol bound to albumin, which may influence the availability of estradiol, considering its low binding affinity to albumin. Because these abnormalities persist after mastectomy, the current results may be important in developing dietary intervention protocols that correct %NPBE and abnormal estradiol distribution on binding proteins.

Adult↗
PubMed1986

Hysteresis of left ventricular end ejection pressure-dimension relations after acute pressure loading in the intact canine heart.

The left ventricular end systolic pressure-volume relation of the isolated canine heart is linear and independent of the loading conditions. The effects of acute pressure loading on the left ventricular end ejection pressure-length relations were studied in the intact canine heart. The lengths of two wall segments of the left ventricle parallel to the minor axis were measured with pairs of miniature piezoelectric crystals. At two levels of filling pressure, with and without control of heart rate, acute increases in left ventricular afterload were produced for six successive beats by occluding the thoracic aorta. After abrupt release of this occlusion, at left ventricular end diastolic pressure less than 10 mmHg, end ejection lengths were longer than before the occlusion for both segments despite the same or lower end ejection pressures. When heart rate was not controlled the mean(SD) difference in end ejection length was 0.46(0.21) mm (n = 100). When heart rate was controlled by atrial pacing after autonomic blockade the difference was 0.37(0.11) mm (n = 80). In contrast, at left ventricular end diastolic pressure greater than 10 mmHg there was no significant difference between end ejection lengths before and after release of the aortic occlusion. Gradual release of the aortic occlusion over 4-5 beats produced clockwise hysteresis of the left ventricular end ejection pressure-length relation when left ventricular end diastolic pressure was less than 10 mmHg. No hysteresis occurred when left ventricular end diastolic pressure was greater than 10 mmHg. Hysteresis of the end systolic pressure-dimension relation was also seen when major and minor axis dimensions of the left ventricular were measured.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Ethinyl estradiol and medroxyprogesterone acetate in patients with epithelial ovarian carcinoma: a phase II study.

Patients with ovarian carcinoma refractory to chemotherapy received a sequential combination of ethinyl estradiol and medroxyprogesterone acetate in two dose regimens. There was no difference in therapeutic activity of the two dose regimens. Of 65 patients, nine (14%) responded to treatment and 13 (20%) had stable disease. Vascular complications occurred in three patients; hemiplegia developed in one of those. Nine patients had significant nausea and vomiting, and one experienced severe depression that required treatment withdrawal. The sequential and combined use of ethinyl estradiol and medroxyprogesterone acetate may provide an alternative treatment for certain patients with ovarian carcinoma that does not respond to optimum chemotherapy. Additional studies are required to determine if synergism exists between this treatment and other modalities of therapy. Further investigation is required into the vascular disorders that complicate therapy to determine whether appropriate preventive measures are possible.

Adult↗
PubMed1986

IgE FAST inhibition: a rapid technique for the standardization of pollen allergen extract potency.

An IgE FAST(TM) inhibition protocol has been developed as a rapid in vitro method for determining relative potencies of in vivo allergenic extracts. Results are obtained within one day and correlate well with those of the RAST inhibition protocol (r = .96), making the FAST assay a preferable procedure for inprocess potency determination during the manufacture of standardized allergenic extracts.

Allergens↗
PubMed1986

Regional and global myocardial function in the dog when nitrous oxide is added to halothane in the presence of critical coronary artery constriction.

The effect of substituting 66% nitrous oxide for nitrogen on global and regional myocardial function before and after critical constriction of the left anterior descending coronary artery (LAD) was studied in six open-chested dogs anesthetized with 1% halothane (inspired). Regional myocardial function was measured in the region of the LAD and in the region of the left circumflex artery using sonomicrometry, and LAD blood flow was measured. Administration of nitrous oxide produced moderate depression of global performance. Regional shortening in both myocardial segments was reduced, and dysfunction also appeared in the LAD segment. This dysfunction was observed in the presence of both normal coronary blood flow, and after critical constriction. The appearance of dysfunction when coronary blood flow was unimpaired suggests that ischemia may not be the only cause of regional myocardial dysfunction.

Animals↗
PubMed1985

Effect of muscle tendon vibration on the perception of force.

The effect of vibrating the biceps muscle tendon on the perception of forces exerted by the elbow flexor muscles was examined during briefly maintained, submaximal contractions. Subjects were required to estimate the perceived magnitude of isometric forces exerted by the elbow flexor muscles under normal conditions and during vibration of the right biceps tendon. The matching forces produced by the unperturbed left arm provided an estimate of the perceived intensity of the reference arm contraction. Both force and the brachial biceps and triceps EMGs were recorded from each arm. In comparison with the matching forces produced under normal conditions, there was a significant overestimation of the forces exerted by the vibrated biceps muscle. This increase in the perceived intensity of the reference force was associated with an increase in the EMGs of the biceps and triceps muscles of the reference arm. It appeared that during vibration the triceps muscle was cocontracting presumably as a means of controlling the reference force. The overestimation of the forces exerted by the vibrated muscle could therefore reflect either the enhanced excitatory drive required to overcome the antagonist activity, or the concomitant increase in the force generated by the agonist muscle. Previous results suggest that the former is the more probable explanation.

Adult↗
PubMed1985

Source derivation of the brain-stem auditory evoked potential.

This study described the results of applying source derivation to the brain-stem auditory evoked potential. Unilateral stimulation gives rise to current sinks, associated with waves I and III, which are located in the vicinity of the ipsilateral mastoid. Waves II and V are associated with a pair of current sinks which appear bilaterally in the vicinity of each mastoid.

Adult↗
PubMed1985

Precision of anthropometric measurements: the value of mid-arm circumference.

A study was carried out to examine how reproducible anthropometric measurements were within and between two observers on a group of 24 normal subjects and 20 obese individuals. A further study was performed on 28 malnourished patients with Crohn's disease undergoing a controlled trial of nutritional therapy to assess how weight change correlated with other anthropometric parameters. The measurement that was most reproducible and correlated most with weight change was mid-arm circumference. As it is the simplest measurement to perform, we would recommend that it is used more often in nutritional studies.

Journal Article↗
PubMed1985

Postsystolic shortening of canine left ventricle supplied by a stenotic coronary artery when nitrous oxide is added in the presence of narcotics.

The effects of fentanyl and sufentanil with and without N2O on left ventricular myocardium supplied by a critically narrowed and a normal coronary artery were studied in 16 dogs. Regional ventricular function was measured by recording ventricular segment length with the use of ultrasonic length detectors in the left anterior descending (LAD) and the left circumflex (LC) coronary artery territories before and during critical stenosis of the LAD. Critical stenosis was documented by the absence of a hyperemic response following a 10-s total occlusion of the LAD. Hemodynamic variables (aortic flow and pressure, left ventricular pressure, heart rate, and coronary blood flow) were measured and the first derivative of left ventricular pressure (LVdP/dt) and coronary perfusion pressure derived. Eight dogs received fentanyl 100 micrograms X kg-1 followed by an infusion of 1 microgram X kg-1 X min-1 while ventilated with O2:N2 (1:2), and eight dogs received sufentanil 30 micrograms X kg-1 with an infusion of 0.3 micrograms X kg-1 X min-1. Replacement of N2 with N2O produced evidence of mild systolic myocardial depression but no dysfunction in either group. After application of the critical constriction, the addition of N2O rapidly produced evidence of dysfunction with significant postsystolic shortening only in the LAD territory. This was not accompanied by hypotension or a decrease in coronary flow and was not always reversible. Higher infusion rates of either narcotic (fentanyl 2 micrograms X kg-1 X min-1, 4 micrograms X kg-1 X min-1; sufentanil 0.6 micrograms X kg-1 X min-1, 1.2 micrograms X kg-1 X min-1) in the absence of N2O did not produce dysfunction but had no protective effect when N2O was added.(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthetics↗
PubMed1985

New actinophage species.

All actinophages of known morphology are tailed. From 305 phages surveyed, 4 belong to the Myoviridae family, 283 to the Siphoviridae, and 18 to the Podoviridae (two morphotypes each). 58 of 139 actinophages described since 1976 are classified in this report, and the earlier phage descriptions are updated. Nine new species and type viruses are proposed, bringing the total number of actinophage species to 29 and the number of bacterial host genera to 15.

Actinomycetales↗
PubMed1985

Brainstem auditory evoked potentials in chronic renal failure and maintenance hemodialysis.

Brainstem auditory evoked potentials (BAEPs) were recorded in 36 chronic uremic patients maintained on hemodialysis and in 10 normal controls. Both absolute response latencies and central transmission times were affected. There were transitory increases in interpeak latencies of I-II and III-V that were reversed by dialysis. A permanent increase in wave III-V interpeak latency was not reversed by dialysis. Wave II-III interpeak latency was unaffected.

Adult↗
PubMed1985

Tamoxifen therapy of epithelial ovarian cancer.

The activity of the antiestrogen tamoxifen was evaluated in 23 patients with epithelial ovarian carcinoma. All patients had received cytotoxic chemotherapy. The patients were given daily doses of 20 or 40 mg tamoxifen orally for a minimum of eight weeks. No objective tumor regressions were noted. In 19 patients disease remained stable for a median duration of 17 weeks (range: eight to 47 weeks). Estrogen and/or progesterone levels available for six patients did not correlate with stability of disease. The authors conclude that tamoxifen does not induce objective response in patients with epithelial ovarian carcinoma who have been treated with cytotoxic chemotherapy. However, in the current study about 80% of such patients had short-lived objective stabilization of their disease.

Adolescent↗