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B Jackson

Publications and source records attributed to B Jackson.

At least 325 records · Page 18Linked to original sources
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Measurement of lead in blood by graphite furnace atomic absorption spectrometry.

A simple method of deproteinizing whole blood with an 0.8M (5%, v/v) nitric acid solution containing Triton X-100 (0.1%, v/v) is described. The resulting supernatant is used for the measurement of lead by Zeeman graphite furnace atomic absorption spectrometry using calibration with aqueous standards. Recoveries ranged from 97.7-105.6% when an aqueous lead solution was added to a deproteinized sample supernatant and from 98.5-104.5% when whole blood control material was added to a whole blood sample. At a blood lead concentration of 11.2 micrograms/dL, the within- and between-run coefficients of variation were both approximately 5%. Comparison of the proposed method versus one using a recommended matrix modifier gave a regression equation of Y(proposed) = 0.99x(matrix modifier)-0.36, with a correlation coefficient of r = 0.994 (n = 54).

Graphite↗
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Angiotensin converting enzyme during acute and chronic enalapril therapy in essential hypertension.

The acute and chronic effects of enalapril (MK421) were assessed in a double-blind randomized trial in subjects with essential hypertension. In acute studies, twelve subjects received enalapril (10 mg p.o.), following which there was a fall in blood pressure, maximal at 6 h and lasting for 24 h. Serum MK422 (enalaprilic acid, the bioactive form of enalapril) and serum angiotensin converting enzyme (ACE) inhibition had a similar time course with good correlation between drug levels and ACE inhibition (P less than 0.001, r = 0.98, n = 16) and between ACE inhibition and the hypotensive effect (P less than 0.001, r = 0.84, n = 16). In chronic studies enalapril was titrated from 5 mg to 20 mg twice a day in eleven hypertensive patients to achieve a diastolic blood pressure less than 90 mmHg. Treatment continued for 3-12 months. Increasing serum MK422 was correlated with reducing serum ACE activity (P less than 0.001, r = 0.8, n = 104). The fall in blood pressure correlated both with serum MK422 level (P less than 0.05, r = 0.37, n = 39) as well as ACE inhibition (P less than 0.01, r = 0.45, n = 42). The drug level:ACE inhibition curve was shifted to the right during chronic enalapril treatment. ID50 for serum ACE was 32 ng MK422/ml following the single 10 mg dose of MK421 and 70 ng MK422/ml during chronic treatment. Blood pressure falls during acute and chronic treatment were similar over the range of serum MK422 levels achieved. The shift in the drug level:ACE inhibition curve suggests induction of ACE during chronic treatment with enalapril in man.

Angiotensin-Converting Enzyme Inhibitors↗
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Angiotensin converting enzyme and substance P changes in blister fluid following afferent nerve stimulation in the rat.

We have examined the effect of electrical nerve stimulation on substance P and angiotensin converting enzyme activity in the interstitial fluid of rat skin using a blister model. Following sciatic nerve stimulation, blister fluid immunoreactive substance P (fmol/ml) was increased from 118 (unstimulated side, s.e.m. = 13, n = 15) to 197 (stimulated side, s.e.m. = 26, n = 15, P less than 0.0125, paired t-test, 14 d.f.). Angiotensin converting enzyme (ACE) activity (nmol HL/ml per h) was reduced in blister fluid from 26.5 (unstimulated side, s.e.m. = 2.4, n = 12) to 22.4 (stimulated side, s.e.m. = 1.4, P less than 0.05, paired t-test, 11 d.f.). Electrical stimulation of afferent nerves inhibits angiotensin converting enzyme activity in vivo. This may contribute to the process of neurogenic inflammation.

Animals↗
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Occupational health.

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Career Mobility↗
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Muddled by the media.

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Communications Media↗
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Platelet utilization in a university hospital.

Two hundred forty-three patients received 22,717 U of platelets in our hospital during a three-month period. Those with hematologic diseases accounted for 43% of the patients but used 86% of the platelets. Sixty-eight percent of the transfusions were given to prevent bleeding and 32% were given to treat active bleeding. Ninety-two percent of therapeutic transfusions but only 22% of prophylactic transfusions met guidelines established by the Transfusion Therapeutics Committee of the University of Minnesota Hospital and Clinics, Minneapolis. However, 78% of prophylactic platelet transfusions that did not meet the guidelines involved patients with at least one clinical factor that their physicians believed placed them at an increased risk of bleeding. Following this analysis, the guidelines were modified and applied prospectively to requests for platelets. This resulted in a 14% decrease in the number of platelet units used during the following year. We conclude that published recommendations for platelet transfusions do not reflect the complex nature of many patients' conditions and that the use of guidelines developed by the medical staff can alter the use of platelet transfusions.

Adult↗