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Biomedical subjects

I B Hirsch

Publications and source records attributed to I B Hirsch.

At least 37 records · Page 2Linked to original sources
PubMed1997

Diabetes management in special situations.

Clinicians are frequently required to manage situations for which few data are available in the literature. Medical therapies for these situations are frequently based on graduate and postgraduate training, community standards, and personal experience. For individuals with diabetes, this would include perioperative diabetes management, the management of diabetes while discontinuing an insulin infusion, and the management of diabetes during treatment with glucocorticoids and TPN. Clinicians may disagree with some of the recommendations for these four situations, and implementation of these suggestions may not be possible at all hospitals. The therapies described herein are based on the pathophysiology of the respective situation and the pharmacokinetic and pharmacodynamic properties of available medications, particularly insulin. The introduction of new insulin analogues and agents to treat insulin resistance may improve our ability to treat diabetes in special situations. Future investigations should focus on how to best use these tools during critical times.

Anesthesia, General↗
PubMed1996

Effect of stepped hypoglycemia on regional cerebral blood flow response to physiological brain activation.

The effect of vasoactive stimuli on cerebral blood flow (CBF) has been variously reported as normal or impaired by hypoglycemia. We measured regional CBF (rCBF) in contralateral somato-sensory cortex at rest and during vibrotactile stimulation of one hand in four normal awake human volunteers during fasting euglycemia (5.1-5.2 mumol/ml) with 0.9% saline infusion, euglycemia (5.1-5.2 mumol/ml) with hyperinsulinemic clamp, mild hypoglycemia (3.2-3.6 mumol/ml) with hyperinsulinemic clamp, and moderate hypoglycemia (2.3-3.2 mumol/ml) with hyperinsulinemic clamp. No changes in mean arterial pressure, arterial PCO2, or arterial oxygen content occurred. There was no change in the magnitude of the normalized rCBF response to physiological brain stimulation with progressive arterial hypoglycemia (r = 0.10, P = 0.73). We interpret this to mean that there was a progressive reduction in cerebral glucose delivery to the area of physiological activation as arterial glucose concentrations fell. Therefore, the increase in rCBF during physiological brain activation is not regulated by a mechanism that matches local cerebral glucose supply to local cerebral glucose demand.

Adult↗
PubMed1996

Surveillance for complications of diabetes: don't wait for symptoms before intervening.

Surveillance and treatment of diabetes-related complications should be part of routine care of all patients with diabetes. The natural history and screening recommendations for diabetic retinopathy, nephropathy, and neuropathy must be understood, since even advanced disease can be asymptomatic. Most adults require yearly ophthalmologic evaluations and determinations of albuminuria. Regular foot examinations by the patient and physician are required, with special attention to identifying patients with increased susceptibility to neuropathic ulcer and lower extremity amputation (ie, the "high-risk foot"). Cardiac autonomic neuropathy has become easier to diagnose, and its presence has several implications. Measurement of lipid levels and glycosylated hemoglobin and assessment of nutritional health should also be included in evaluation. Although understanding and prevention of diabetes complications are improving, the impact of end-organ damage remains a major problem. Early diagnosis and treatment often improve outcome and should dramatically decrease the burden of diabetes in our society.

Albuminuria↗
PubMed1995

Long QT syndrome during high-dose cisapride.

The gastrointestinal prokinetic drug, cisapride, is widely used for the treatment of diabetic gastroparesis and disorders of gastrointestinal motility. We present a case of acquired QT prolongation, syncope, and nonsustained ventricular tachycardia associated with high doses of cisapride.

Cisapride↗
PubMed1994

Reduced plasma peroxyl radical trapping capacity and increased susceptibility of LDL to oxidation in poorly controlled IDDM.

Oxidation of low-density lipoproteins (LDLs) has been postulated to play an important role in atherogenesis. Because oxidant stress may be increased and antioxidant defenses reduced in diabetes, the susceptibility of LDL to oxidative modification and total peroxyl radical trapping potential (TRAP) of plasma were evaluated in subjects with poorly controlled insulin-dependent diabetes mellitus (IDDM). The lag phase of conjugated diene formation after initiation of LDL oxidation by the addition of copper was shorter in diabetic subjects than in normal control subjects (126 +/- 11 vs. 165 +/- 15 min [means +/- SE], P < 0.05). This could not be attributed to the presence of oxidation-susceptible, small, dense LDL particles in the diabetic subjects, whose lipoprotein particle distribution did not differ from the control subjects. However, the total TRAP of plasma, a measure of antioxidant defense, was reduced (626 +/- 34 vs. 877 +/- 41 microM, P < 0.0001) in diabetes. Of the plasma antioxidants measured, only uric acid and vitamin A were decreased in diabetes (P < 0.01), and both levels correlated with TRAP (r = 0.75, P < 0.001; r = 0.54, P < 0.001, respectively). The correlation between uric acid levels and TRAP persisted when the diabetes and control groups were analyzed separately. The reduced TRAP of plasma and the increased susceptibility of LDL to oxidative modification observed is consistent with a role for lipoprotein oxidation in the pathogenesis of atherosclerosis in IDDM.

Adult↗
PubMed1994

Physicians' practices in screening for the development of diabetic nephropathy and the use of glycosylated hemoglobin levels.

OBJECTIVE: To compare outpatient screening of diabetic patients for nephropathy and measurement of glycosylated hemoglobin (GHb) levels to published American Diabetes Association (ADA) guidelines. RESEARCH DESIGN AND METHODS: We reviewed charts from 157 diabetic patients followed for 27 months at the University of Washington's primary care clinics. The number of screening urinalyses, 24-h urine measurements, and GHb measurements were obtained. From these values, the frequency of screening tests, normalized by patient-year, could be compared with the ADA guidelines. RESULTS: Forty-two percent of the patients received at least one urinalysis, and 5% had 24-h urine measurements. There were 0.48 urinalyses and 0.05 24-h urine measurements per patient-year. Of 14 type I diabetes patients, 5 had a urinalysis and 1 received a 24-h urine measurement. At least one GHb was measured for 85% of patients, and there were 1.66 GHb measurements per patient-year. Only 29% of patients received GHb concentrations as recommended by ADA guidelines. CONCLUSIONS: Diabetic patients at this institution are not screened for nephropathy and do not receive GHb measurements according to the ADA guidelines. Because of recent advancements in the treatment of diabetic nephropathy and the results of the Diabetes Control and Complications Trial (DCCT), further efforts are needed for educating primary care physicians about standards of care of patients with diabetes.

Diabetic Nephropathies↗
PubMed1993

Unaltered cerebral blood flow during hypoglycemic activation of the sympathochromaffin system in humans.

To determine if increases in plasma epinephrine and norepinephrine caused by hypoglycemia are associated with increments in cerebral blood flow (CBF), we measured CBF with positron emission tomography in normal humans at ambient fasting arterial plasma glucose levels and at clamped plasma glucose levels of 5.3, 3.5, and 2.8 mmol/l using the hyperinsulinemic, stepped hypoglycemic clamp technique. Despite significant increases in plasma epinephrine to 7,340 +/- 350 (SE) pmol/l and in plasma norepinephrine to 3.32 +/- 0.35 nmol/l, mean hemispheric CBF (41 +/- 1, 49 +/- 1, 48 +/- 2, and 51 +/- 3 ml x 100 g-1 x min-1) remained constant at the ambient (5.2), 5.3, 3.5, and 2.8 mmol/l glycemic levels, respectively. Furthermore, there was no correlation between CBF and either plasma epinephrine levels ranging from 160 to 10,580 pmol/l or plasma norepinephrine levels ranging from 0.56 to 5.10 nmol/l. Failure to demonstrate any dose-response relationship between plasma catecholamine levels and CBF argues against their primary role in cerebrovascular control during hypoglycemia.

Adult↗
PubMed1993

Time for a change.

Explore the source record for details and available documents.

Certification↗
PubMed1993

Type I diabetes and insulin therapy.

Intensive insulin therapy is composed of an entire therapeutic program of diabetes management. One component of that program is a multiple-component insulin regimen. There are several important pharmacokinetic issues that must be appreciated when prescribing insulin. These include differences in absorption characteristics between animal and human insulin, variations in intraindividual insulin absorption, the influence of injection sites on insulin absorption, and lag time. Only physiologic insulin regimens should be used in patients with type I diabetes, and there are advantages and disadvantages to the various available options. There are theoretic reasons why CSII may be better for many patients. Finally, the nurse specialist/educator who is initiating the insulin therapy should be familiar with the general guidelines for the various insulin regimens in addition to implementing appropriate diabetes algorithms.

Absorption↗
PubMed1992

Intensive insulin therapy: Part I. Basic principles.

Intensive insulin therapy is a complete program of diabetes management. A multicomponent insulin regimen is just one element of this approach. Intensive insulin therapy does not necessarily strive for euglycemia, since patients require individualized glycemic goals. When prescribing insulin, the family physician should be familiar with several important pharmacokinetic issues. Insulin species, insulin absorption, injection site and timing of premeal insulin all affect glycemia. The relationship between diabetic complications and blood glucose control is also important. Although many previous studies have been flawed, evidence suggests that meticulous diabetes control decreases the risk of microvascular complications and neuropathy. Unfortunately, studies have shown no improvement in advanced retinopathy or advanced nephropathy with improved glycemic control. The major cost of improved glycemic control is an increased risk of hypoglycemia.

Blood Glucose↗
PubMed1992

Intensive insulin therapy: Part II. Multicomponent insulin regimens.

In patients with insulin-dependent diabetes mellitus, insulin is an absolute requirement for life. Once-daily insulin administration is not sufficient to maintain physiologic insulin delivery. Twice-daily delivery of a combination of intermediate-acting and regular insulin may be effective but may limit lifestyle flexibility. Other popular regimens include three daily injections (with a bedtime dose of intermediate-acting insulin) and use of a combination of ultralente and regular insulin. Continuous subcutaneous insulin infusion is another option for patients with insulin-dependent diabetes. In patients with noninsulin-dependent diabetes who require insulin, control can often be achieved with a single daily injection. Recently, the use of bedtime NPH or ultralente insulin has been emphasized for control of moderate hyperglycemia in these patients. For patients with severe hyperglycemia, insulin administration is similar to that for patients with insulin-dependent diabetes. The use of combination therapy with insulin and sulfonylurea for noninsulin-dependent diabetes is controversial.

Blood Glucose↗
PubMed1991

Increased symptoms of hypoglycaemia in the standing position in insulin-dependent diabetes mellitus.

1. To test the hypothesis that patients with insulin-dependent diabetes mellitus perceive the symptoms of hypoglycaemia to a greater extent when they are in the standing position than when they are in the lying position, we assessed symptoms of hypoglycaemia, as well as heart rate and plasma noradrenaline and adrenaline concentrations, in both positions during hyperinsulinaemic glucose clamps on three occasions in seven patients. 2. Plasma glucose concentrations were clamped at 5.0 mmol/l (90 mg/dl) and 5.0 mmol/l on one occasion, at 5.0 mmol/l and 3.9 mmol/l (70 mg/dl) on another occasion, and at 5.0 mmol/l and 2.8 mmol/l (50 mg/dl) on yet another occasion. 3. During euglycaemia there was no effect of position on the symptom panels used to assess the symptomatic response to hypoglycaemia. However, at the plasma glucose concentration of 2.8 mmol/l, total (P less than 0.003) and neurogenic (P less than 0.005), but not neuroglycopenic, hypoglycaemic symptom scores were higher with the patients in the standing than in the lying position. Increments in total hypoglycaemic symptom scores, over those during the corresponding euglycaemic phase, were 5 +/- 2 in the lying position and 11 +/- 2 in the standing position (means +/- SEM, P less than 0.01). 4. Thus patients with insulin-dependent diabetes mellitus perceive symptoms of hypoglycaemia to a greater extent when they are in the standing position than when they are in the lying position because of enhanced neurogenic symptoms.

Adult↗
PubMed1991

Insulin and glucagon in prevention of hypoglycemia during exercise in humans.

To assess the roles of decrements in insulin and increments in glucagon in the prevention of hypoglycemia during moderate exercise (approximately 60% peak O2 consumption for 60 min), normal young men were studied during somatostatin infusions with insulin and glucagon infused to 1) hold insulin and glucagon levels constant, 2) decrease insulin, 3) increase glucagon, and 4) decrease insulin and increase glucagon during exercise. In contrast to a comparison study (saline infusion), when insulin and glucagon were held constant, glucose production did not increase and plasma glucose decreased from 5.5 +/- 0.2 to 3.4 +/- 0.2 mmol/l (P less than 0.001) initially during exercise. Notably, plasma glucose then plateaued and was 3.3 +/- 0.2 mmol/l at the end of exercise. This decrease was at most only delayed when either insulin was decreased or glucagon was increased independently. However, when insulin was decreased and glucagon was increased simultaneously, there was an initial increase in glucose production, and the glucose level was 4.5 +/- 0.2 mmol/l at 60 min, a value not different from that in the comparison study. Thus we conclude that both decrements in insulin and increments in glucagon play important roles in the prevention of hypoglycemia during exercise and do so by signaling increments in glucose production. However, since hypoglycemia did not develop during exercise when changes in insulin and glucagon were prevented, an additional counterregulatory factor, such as epinephrine, must be involved in the prevention of hypoglycemia during exercise, at least when the primary factors, insulin and glucagon, are inoperative.

3-Hydroxybutyric Acid↗