Nonenzymatic glycation of fibronectin and alterations in the molecular association of cell matrix and basement membrane components in diabetes mellitus.

This study reports the nonenzymatic glycation of plasma fibronectin in vivo in diabetic dogs and also in vitro by incubation of human plasma fibronectin with excess glucose. Although no difference is observed in the total plasma fibronectin level, the nonenzymatic glycation of fibronectin is increased 2.3-fold in inbred male beagle dogs made diabetic with alloxan in comparison with age-matched controls. The extent of non-enzymatic glycation of fibronectin is shown to be proportional to blood glucose levels. HPLC reverse-phase analysis of the hydrolyzed amino acids and glyco-amino acids from plasma fibronectin samples of normal and diabetic dogs show that nonenzymatic glycation occurs only on lysine residues. When purified human plasma fibronectin was incubated in vitro with 500 mM glucose, the extent of nonenzymatic glycation of fibronectin was observed to increase proportionately with time. Ligand binding assays conducted in solution with varying concentrations of 3H-heparin in the presence of a constant amount of normal or nonenzymatically glycated human plasma fibronectin gave virtually identical binding curves. However, the binding of 3H-heparin to normal fibronectin could be increased fourfold by the concomitant addition of normal gelatin (denatured calfskin collagen). If in vitro glycated fibronectin and/or in vitro glycated gelatin are added under this latter condition with 3H-heparin, there is a tremendous decrease in the expected heparin binding seen with normal levels of nonenzymatic glycation. Other experiments were performed to quantitate the binding of 3H-labeled fibronectin to gelatin-coated nitrocellulose filters. Nonenzymatic glycation of fibronectin in vitro resulted in markedly decreased binding of 3H-fibronectin to collagen.(ABSTRACT TRUNCATED AT 250 WORDS)

Glycerol prevents insulin precipitation and interruption of flow in an implantable insulin infusion pump.

Insulin precipitation is a major obstacle to the use of implantable insulin infusion pumps. In one such pump (Infusaid, Infusaid Corporation, Norwood, Massachusetts), unprotected insulin precipitated and occluded nine pumps implanted in normal dogs within 43 days. In contrast, two similar pumps containing insulin mixed with 80% glycerol functioned normally for more than 250 days. In human studies, a similar mixture allowed insulin to be delivered to nine diabetic subjects for more than 6 mo in each case; total fluid flow rates from the pump were essentially unchanged after 460 patients-weeks of insulin infusion. A possible drawback of the mixture is a time- and temperature-dependent propensity to cause the formation of soluble, higher-molecular-weight insulin polymers, which apparently have lower biologic activity. Formation of such polymers and maintenance of biologic activity were largely prevented by the addition of phosphate buffer at neutral pH.

Reduction of plasma cholesterol and LDL-cholesterol by continuous intravenous insulin infusion.

We studied lipid profiles in 10 patients with insulin-requiring type II diabetes. Patients began the study under conventional subcutaneous insulin injection therapy. Treatment was then optimized on subcutaneous therapy and finally converted to continuous intravenous therapy from a single flow rate implantable pump. Pump management proved reliable and safe. Implantable pump therapy showed a statistically significant reduction in the average plasma cholesterol level from 205.7 to 184.7 mg/dl. The mean low-density lipoproteins (LDL)-cholesterol level decreased from 114.6 to 108.1 mg/dl, the high-density lipoproteins (HDL)-cholesterol average changed from 50.6 to 51.0 mg/dl, and the HDL/LDL ratio increased from 0.478 to 0.500. Glycemic control did not improve on single-rate intravenous therapy compared with intensive conventional subcutaneous injection during the short observation period. The authors conclude that additional studies should be performed to confirm the improvement in the lipid profile on intravenous pump therapy.

Gastritis after gastric bypass surgery.

To determine the preferable reconstruction of gastrointestinal continuity after gastric bypass, we studied by endoscopic, chemical, and histologic analyses 28 randomly selected patients with a loop gastroenterostomy, a loop gastroenterostomy plus enteroenterostomy between the afferent and efferent loops, and a Roux-en-Y anastomosis. Total bile acid levels for the three groups were: 5092 +/- 1673 mumol/L, 1638 +/- 581 mumol/L, and 404 +/- 384 mumol/L, respectively. The incidence of gastritis by endoscopy was 71% in the standard loop bypass, 45% in the enteroenterostomy group, and 13% in the Roux-en-Y group. Histologic abnormalities were present in 86% of the patients who underwent standard loop bypass, in 91% of those with an additional enteroenterostomy, and in 63% of the Roux-en-Y group. There was poor correlation of symptoms and objective findings. In our study Roux-en-Y reconstruction after gastric bypass, in comparison with loop gastroenterostomy or loop gastroenterostomy with an additional enteroenterostomy, is less likely to result in bile in the stomach, endoscopic changes, and histologic abnormalities.

Hemodynamics of congenital diaphragmatic hernia in lambs.

Despite surgical treatment, congenital foramen of Bochdalek diaphragmatic hernia continues to carry a high mortality rate due to associated respiratory insufficiency. We studied the pathologic and hemodynamic changes that result from this condition in lambs. Surgical creation of diaphragmatic hernias in fetal lambs was performed in utero with subsequent delivery by cesarean section near term. Cardiac catheterization was performed on these newborn lambs immediately after delivery, before and after surgical repair of the defect. Data from five of these lambs were compared to data obtained from seven normal lambs. Pulmonary hypertension was found only in lambs with hernias. Pulmonary artery pressures and the mean ratio of pulmonary to systemic resistance were higher in experimental lambs. Oxygen saturation and average cardiac index were higher in normals. Lambs in the experimental group, but not in the control group, had large left-to-right shunts at the level of the ductus arteriosus in the early neonatal period. Arterial oxygen saturations were consistently low with no differences in pre- and post-ductal samples, which suggests right-to-left shunting at the atrial level or physiologic shunting across the unexpanded lungs. No further expansion of the hypoplastic lungs occurred following decompression by surgical hernia repair, but transient hemodynamic improvement was noted in some cases. Surgical ligation of the ductus arteriosus did not significantly alter the clinical condition of the lambs. Lungs in lambs with hernias were grossly abnormal, the left appearing more hypoplastic than the right.

Failure to find amyloidosis in dogs treated with long-term intravenous insulin delivered by a totally implantable pump.

We examined tissues of seven non-diabetic mongrel dogs and four diabetic beagle dogs treated with constant insulin infusion via totally implantable pumps for from 210 to 880 days. Kidney and skeletal muscle tissue from all dogs were stained with Congo Red and thioflavin-T and appropriately examined. Kidney tissues from the beagle dogs were examined by electron microscopy. No amyloid deposits were found in any of these tissues. Thus, we cannot confirm an earlier report of amyloid occurring in dogs given long-term intravenous insulin. It is concluded that amyloidosis is not a necessary complication of long-term intravenous insulin infusion in dogs.

A double balloon catheter technique for alloxan diabetogenesis in the dog.

Venous injection of alloxan monohydrate is a standard method to produce a canine model of diabetes. Others have reported mortalities greater than 45 per cent and yields of diabetic dogs of less than 36 per cent with this technique. In this study, a new method for alloxan diabetogenesis is reported upon: alloxan monohydrate is injected intravenously with protection of the renal arteries at the time of injection by a 7F, triple lumen double balloon catheter placed in the abdominal aorta. The balloons are inflated under fluoroscopic control to occlude the renal arteries at the time of injection. Forty-three age-matched beagle dogs were initially injected with 60 milligrams per kilogram of alloxan monohydrate: 26 or 61 per cent became diabetic-defined as persistently doubled fasting serum glucose and glucosuria; ten failed to become diabetic, 23 per cent, and seven died, 16 per cent. The ten initial failures were reinjected with 65 milligrams per kilogram of alloxan monohydrate: six or 60 per cent then became diabetic, three were persistent failures, 30 per cent, and one dog died, 10 per cent. Thus, the over-all yield of diabetic dogs was 74 per cent, with an 18 per cent mortality. Minimal renal damage occurred, as evidenced by creatinine clearance, blood urea nitrogen and renal biopsy studies. These results suggest a significantly improved method--a twofold improvement over standard success rates with a twofold less mortality--of producing diabetic dogs by alloxan injection.

Chronic obstructive pulmonary disease: a community-oriented program including professional education and screening by a voluntary health agency.

A community program for chronic obstructive pulmonary disease that included detection by screening, professional education, community involvement, and evaluation of results is described. Key figures in the success of this program were senior medical students. In the first community, in which no professional education was offered, 45.3% of persons screened who had abnormal test results came away from their physicians understanding that they did not have a significant health problem. In subsequent communities, in which professional education was a part of the program, this percentage decreased steadily to approximately 11%. Consistently, 25% of the persons screened who had abnormal results did not consult a physician. Twenty-one % of the participants with abnormal results of screening and no previous knowledge of pulmonary disease stopped smoking in the ensuing 2 to 3 yr, whereas only 11.7% of the control group of persons with normal screening results did so.

Diabetic nephropathy in the uninephrectomized dog: microscopic lesions after one year.

Carefully age-matched, purebred male beagle dogs that underwent uninephrectomy one month after they were made diabetic with alloxan were used to establish a model of rapidly developing diabetic nephropathy in a large animal. The diabetic animals, all requiring insulin, were divided into two groups: one group with control by insulin injections permitting elevated fasting and postprandial serum glucose values and substantial glycosuria; the other with better control and with near-normal serum glucose levels and less glycosuria. By 1 year of diabetes both diabetic groups had renal lesions different from the uninephrectomized control animals but differing only slightly from one another. With light microscopy, diabetic dogs had increased mesangial thickening. With electron microscopic morphometry, glomeruli of diabetic subjects demonstrated increased fractional volumes of the total mesangium and of its cellular and matrix components and increased width of the GBM. These quantitative measures of diabetic nephropathy in the dog within 1 year of onset of the disease describe a model potentially useful in evaluating the efficacy of improved diabetic control in preventing or ameliorating diabetic nephropathy.

Implantable infusion pump management of insulin resistant diabetes mellitus.

Diabetes mellitus with resistance to insulin administered subcutaneously or intramuscularly (DRIASM) is a rare and brittle form of Type I diabetes, found predominantly in young females and characterized by inadequate glycemic response to subcutaneous or intramuscular insulin administration. DRIASM leads to frequent ketoacidosis and obligatory hospitalization for administration of intravenous insulin. The use of a totally implantable infusion pump effected dramatic improvement in the treatment of five patients with this difficult form of diabetes. Frequency of clinical ketoacidosis was reduced from 37 episodes per year to 0.4 episodes per year (99%), and average in-hospital days per month were reduced from 20.8 days to 2.2 days (89%) with a mean follow-up period of 14.4 months. Cost savings were approximately +10,000 per patient month. Quality of life was greatly improved for these individuals.

The use of an implantable insulin pump in the treatment of type II diabetes.

We treated five patients with Type II diabetes by means of a subcutaneously implanted intravenous insulin pump and compared their metabolic response with that observed during conventional insulin therapy. The use of the pump improved control of glycemia, as manifested by reductions in mean plasma glucose (from 188 +/- 46 to 106 +/- 12 mg per deciliter [mean +/- S.D.]), fasting glucose (from 187 +/- 42 to 80 +/- 13 mg per deciliter), and postprandial glucose (from 287 +/- 74 to 182 +/- 29 mg per deciliter), together with a diminution of glycemic excursion and normalization of glycosylated hemoglobin A1 (from 12.1 +/- 2 to 8.0 +/- 1 per cent). At the end of the study the pumps had been in place for a mean of 7.0 months (range, 5.5 to 9.7 months) without mishap and with good patient acceptance. Our data suggest that improved blood glucose control can be achieved by means of a permanently implanted continuous insulin-infusion device in ambulatory patients with Type II diabetes who require insulin, and that the need for daily insulin injections can thereby be eliminated.