john herr psychologist los gatos saratoga california

On Sabbatical

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TITLE: Mechanisms of altered hemodynamic and metabolic responses to insulin in patients with insulin-dependent diabetes mellitus and autonomic dysfunction.
AUTHOR: Makimattila S; Mantysaari M; Schlenzka A; Summanen P; Yki-Jarvinen H
AUTHOR AFFILIATION: Department of Medicine, Helsinki University Central Hospital, Finland.
SOURCE: J Clin Endocrinol Metab 1998 Feb;83(2):468-75
NLM CIT. ID: 98128688
ABSTRACT: Patients with autonomic neuropathy are more susceptible to insulin-induced hypotension than normal subjects, but the mechanisms are unclear. We quantitated the hemodynamic and metabolic effects of two doses of i.v. insulin (1 and 5 mU/kg.min, 120 min each) and several aspects of autonomic function in 28 patients with insulin-dependent diabetes mellitus (IDDM) and in 7 matched normal subjects under standardized normoglycemic conditions. The autonomic function tests included those predominantly assessing the integrity of vagal heart rate control (the expiration inspiration ratio during deep breathing and high frequency power of heart rate variability) and tests measuring sympathetic nervous function (reflex vasoconstriction to cold and blood pressure responses to standing and handgrip). During hyperinsulinemia, heart rate increased less (2 +/- 1 vs. 6 +/- 2 beats/min; P <0.04) and diastolic blood pressure fell more (-3.1 +/- 1.2 vs. 0.9 +/- 2.1; P="NS)" in the patients with IDDM than in the normal subjects. Forearm vascular resistance decreased significantly in the patients with IDDM [by 7.1 +/- 1.4 mm Hg/(mL/dL.min); P < 0.001 for high vs. low dose insulin], but not in the normal subjects (-0.1 +/- 2.5 mm Hg/(mL/dL.min; P="NS)." Reflex vasoconstriction to cold was inversely correlated with the decreases in diastolic (r="-0.51;" P < 0.005) and systolic (r="-0.59;" P < 0.001) blood pressure and forearm vascular resistance (r="-0.53;" P < 0.005), but not with the change in heart rate. The expiration inspiration ratio was, however, directly correlated with the insulin-induced change in heart rate (r="0.63;" P < 0.001), but not with diastolic or systolic blood pressure or forearm vascular resistance. Whole body (48 +/- 2 vs. 67 +/- 5 mumol/kg.min; P < 0.005) and forearm (44 +/- 4 vs. 67 +/- 8 mumol/kg.min; P < 0.05) glucose uptake were significantly lower in the IDDM patients than in the normal subjects. The latter could be attributed to a defect in the forearm glucose arterio-venous difference (1.5 +/- 0.1 vs. 2.2 +/- 0.2 mmol/L, respectively; P < 0.01), but not in blood flow. We conclude that both impaired vagal heart rate control and sympathetic nervous dysfunction exaggerate the hemodynamic effects of insulin in patients with IDDM and could contribute to insulin-induced hypotension.
MAIN MESH SUBJECTS: Autonomic Nervous System Diseases/*PHYSIOPATHOLOGY
Diabetes Mellitus, Insulin-Dependent/*DRUG THERAPY/ *PHYSIOPATHOLOGY
Diabetic Neuropathies/*PHYSIOPATHOLOGY
Hemodynamics/*DRUG EFFECTS
Blood Flow Velocity/DRUG EFFECTS
Blood Glucose/METABOLISM
Blood Pressure/DRUG EFFECTS
Middle Age
Support, Non-U.S. Gov't
Vascular Resistance/DRUG EFFECTS
REGISTRY NUMBERS: 0 (Blood Glucose)
11061-68-0 (Insulin)

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On Sabbatical!

When my office lease expired at the end of 2004, I decided to turn it into a "sabbatical" from my private practice. Many years ago, in my grandfather's 89th year of life, he told me, "John, it is important to smell the roses while you can still smell them." His life gave living a very good reputation. It is also true that the pursuit of that philosophy required my grandfather to to re-open his assay office/ore market in Wickenburg, Arizona as a 75-year-old because he had run a little short of retirement money. Thus, if blessed with his luck and health, I'll be back.. --jjh

Copyright 1998-2007  John J. Herr, Ph.D.                                   Please send comments to