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Biomedical subjects

D L Horwitz

Publications and source records attributed to D L Horwitz.

At least 19 recordsLinked to original sources
PubMed1989

Factitious and artifactual hypoglycemia.

Artifactual hypoglycemia results from either improper collection of blood samples or interfering substances in the blood. Such artifacts should be easily detected and avoided. Factitious hypoglycemia, on the other hand, results from deliberate subterfuge by the patient and may thus elude proper diagnosis for some time. The most common cause of factitious hypoglycemia is surreptitious injection of insulin, and this is best diagnosed by the triad of hypoglycemia, inappropriately high insulin levels, and low C-peptide levels. Persons with diabetes may also intentionally misuse blood glucose strips to create the impression of hypoglycemia.

Adolescent↗
PubMed1989

Adjustment of caloric intake based on self-monitoring in noninsulin-dependent diabetes mellitus: development and feasibility.

It has been recommended that patients who perform self-blood glucose monitoring use the information gained from the test to alter their diabetic regimen. Skyler et al. have proposed algorithms for patients to adjust their insulin dosage when blood sugar is elevated. However, the clinical result of increasing insulin dosage may be the promotion of weight gain. We proposed that altering the regimen by decreasing caloric intake is an appropriate first approach for NIDDM patients for whom weight loss would be of considerable benefit. Results of an initial needs assessment showed that patients did not generally regard testing and adjusting therapy as important in taking care of diabetes. A recent study by Fox et al. reported similar results, showing that a large portion of patients using blood glucose self-monitoring do not make changes in their regimen when they know that their blood sugar is elevated. Consequently, we implemented a half-day seminar to instruct patients on making adjustments in their dietary regimen on the basis of results of glucose monitoring. Results suggest that our teaching methods were effective in teaching patients to follow the adjusting algorithm. Although we observed trends toward improved metabolic control and weight loss, further studies are required to document the clinical benefit of adjustment of caloric intake based on self-monitoring in diabetes.

Algorithms↗
PubMed1988

Response to single dose of aspartame or saccharin by NIDDM patients.

Twelve normal subjects and 10 subjects with non-insulin-dependent diabetes mellitus were given, in random order at intervals of greater than or equal to 1 wk, three drinks of the same beverage: one unsweetened, one sweetened with 400 mg aspartame, and one sweetened with 135 mg saccharin. The amount of sweetener approximated that in 1 L of sugar-free soft drink. Plasma glucose, insulin, and glucagon were measured for 3 h after ingestion of the test beverage. Plasma glucose declined slightly throughout the test period, probably due to fasting, with no differences between the three treatments. Neither sweetener affected peak insulin levels in subjects with or without diabetes. Analysis of area under the curve showed that mean insulin levels were statistically significantly higher after aspartame than after saccharin or unsweetened beverage in normal subjects only, but the magnitude of the difference was small and unlikely to be of physiological importance in the absence of differences in glucose levels. Furthermore, the differences could largely be accounted for by a decrease in insulin values after both unsweetened beverage and saccharin, with no change from baseline after aspartame. Glucagon levels showed time-to-time variation but no overall differences. We conclude that ingestion of aspartame- or saccharin-sweetened beverages by fasting subjects, with or without diabetes, did not affect blood glucose homeostasis.

Adult↗
PubMed1986

Effect of insulin antibodies and their kinetic characteristics on plasma free insulin dynamics in patients with diabetes mellitus.

To determine the influence of insulin antibodies (and their equilibrium kinetic properties) on the pharmacokinetics of insulin, we examined the relationship between insulin antibody binding and the initial rate of increase, time to peak, and return to baseline of therapeutic doses of insulin injected subcutaneously (0.15 U/kg) and the half-life, distribution space, and metabolic clearance rate of intravenously infused insulin (2 mU/kg/min) in insulin-treated patients with diabetes mellitus. Compared to age-weight-matched nondiabetic subjects, the diabetic subjects had reduced initial rates of increase (0.33 +/- 0.2 v 0.44 +/- 0.03 microU/mL/min, P less than 0.05), delayed time to peak (130 +/- 12 v 86 +/- 8 min, p less than 0.02), and prolonged return to baseline (485 +/- 37 v 313 +/- 13 min, P less than 0.01) of plasma free insulin levels after subcutaneous injection of insulin, and a prolonged half-life (19.8 +/- 5.8 v 4.3 +/- 0.3 min, P less than 0.02), increased distribution space (904 +/- 284 v 109 +/- 10 mL/kg, P less than 0.001), and augmented metabolic clearance rate (28.5 +/- 1.8 v 17.3 +/- 0.7 mL/kg/min, P less than 0.001) after intravenously infused insulin. All of these abnormal parameters were significantly correlated with binding of insulin to insulin antibodies at tracer insulin concentrations (Bo) and with the high affinity of insulin antibody binding sites as determined by Scatchard analysis. However, patients with 125I insulin antibody binding (Bo) less than 10 percent had normal or near normal plasma free insulin pharmacokinetics.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

Synthroid.

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Tablets↗
PubMed1979

Use of a glucose controlled insulin infusion system (artificial beta cell) to control diabetes during surgery.

An artificial beta cell has been used to achieve and maintain a preset plasma glucose concentration in five diabetic patients undergoing surgery. These subjects were compared to control groups of normal subjects receiving either saline or glucose, and diabetics receiving glucose intraoperatively. Hyperglycaemia during surgery was seen in normals (mean plasma glucose +/- SEM: 185 +/- 16 mg/dl) and, to a greater degree, diabetics (247 +/- 36 mg/dl) receiving glucose. Insulin and C-peptide levels did not increase during 2 hours of operation in any of the control groups, suggesting beta cell suppression during surgery. As C-peptide levels declined similarly in normal subjects whether they received saline or glucose, the hyperglycaemia seems to be due to an inability to use exogenous glucose. This is confirmed by a correlation of maximal plasma glucose to glucose infusion rate (r = 0.78, p less than 0.01). The artificial beta cell was able to achieve the same plasma glucose after 2 hours of operation (128 +/- 21 mg/dl) as normal subjects receiving saline (110 +/- 7 mg/dl). The artificial beta cell proved to be a safe, convenient and effective way of monitoring and controlling the hyperglycaemia seen in diabetic patients undergoing surgery.

Blood Glucose↗
PubMed1979

Evaluation of insulin secretory capacity in diabetes mellitus.

The capacity of the pancreatic beta cells to secrete insulin can be evaluated in vivo by measurement either of circulating immunoreactive insulin or of C peptide, a by-product of insulin synthesis. Evaluation of serum levels is complicated, however, by the variable degradation rates and distribution spaces of these peptides. Also, interpretation of peripheral vein concentrations of insulin, and perhaps C peptide, is more difficult because of hepatic catabolism. Quantitation of these peptides in the urine may provide an integrated measure of insulin secretion. In insulin treated diabetic patients who develop circulating insulin antibodies, beta cell secretory capacity may be assessed by C peptide measurement, or by techniques that allow separate determinations of "free" and "total" insulin. A variety of stimulatory tests may be used to investigate insulin secretory capacity.

Adult↗
PubMed1979

An 'artificial beta cell' for control of diabetes mellitus: effect on plasma glucagon levels.

We have investigated the use of a glucose-controlled insulin infusion system, or artificial beta cell. On the feedback day, mean plasma glucose was significantly effect of improved control on plasma glucagon levels. Five insulin-requiring diabetic subjects in stable control were hospitalized for two 24 h periods. During one, they were given their usual dose(s) of subcutaneous insulin. In the other, the 'feedback' day, insulin administration was under feedback control by the artificial beta cell. One the feedback day, mean plasma glucose was significantly-lower in all subjects. Variability in plasma glucose throughout the day was also significantly less on the feedback day. All five subjects showed a significant fall in serum immunoreactive glucagon levels on the feedback day, suggesting that the glucagon abnormalities of diabetes may be secondary to the insulin deficiency, rather than a second primary defect of diabetes.

Adult↗
PubMed1979

Continuous monitoring and control of plasma glucose during operation for removal of insulinomas.

A glucose-controlled insulin and glucose infusion system (Biostator system, Miles Laboratories Inc., Elkhart, Ind.) was used during operation for removal of four suspected insulinomas. In two patients the Biostator system continuously monitored plasma glucose levels and, through a computer-controlled feedback mechanism, automatically infused insulin or glucose as needed. In this way plasma glucose could be kept at approximately 110 mg/dl throughout the procedure. In one patient a rise in insulin infusion rate and a fall in glucose infusion rate followed removal of the tumor. In the other, absence of these findings was consistent with the clinical suspicion that the source of hypoglycemia had not been removed. In two other patients the Biostator system continuously monitored the patient's plasma glucose, without feedback-controlled administration of insulin or glucose. This demonstrated that, in these patients, tumor manipulation and removal did not lead to severe hypoglycemia, and thus eliminated any need to prophylactically infuse large amounts of glucose. Successful tumor removal was followed by a rise in blood glucose levels in both of these individuals. The glucose-controlled insulin and glucose infusion system appears to be a useful instrument for intraoperative management of patients with suspected insulinomas.

Adenoma, Islet Cell↗
PubMed1979

Use of an artificial beta cell in surgery.

Using a Biostator glucose-controlled insulin infusion system to monitor blood glucose during surgery, we have shown that both nondiabetic and diabetic patients have a tendency towards hyperglycemia during surgery. This appears to be due to suppression of endogenous insulin secretion as measured by serum C-peptide levels. Some diabetic patients maintained relatively normal glucose values during surgery when infused with saline alone and not given glucose or insulin, but 2 of 5 were not well controlled by this means. Hyperglycemia in both diabetic and non-diabetic patients was related to the rate of infusion of exogenous glucose. The biostator glucose-controlled insulin infusion system could be used in feedback mode as an apparently safe and effective means of controlling blood glucose during surgery on diabetic patients.

Artificial Organs↗
PubMed1979

Insulin responses to mixed meals: comparison of an artificial beta cell and normal beta cells.

The peripheral glucose and free insulin levels seen following a mixed meal in six insulin-dependent diabetic patients whose insulin was administered by a glucose-controlled insulin infusion system (GCIIS) were compared to those of normal subjects who received the same mixed meal or who were given separately carbohydrate, protein, or fat in amounts equivalent to those contained in the mixed meal. Patients treated with the GCIIS achieved nearly normal glucose levels immediately after the mixed meal, but this was accompanied by marked hyperinsulinemia. In the period from 120 to 240 minutes after the start of the mixed meal, the GCIIS duplicates the insulin levels produced by the normal pancreas after a glucose meal and, with appropriate algorithm constants, closely approximates those seen after a mixed meal.

Artificial Organs↗