Why people don't learn from diabetes literature: influence of text and reader characteristics.

The study was designed to identify text and reader characteristics that impede learning. Twenty-six adults with diabetes mellitus took a 15-item test for prior knowledge of diabetes, a 20-item vocabulary test, and a Need for Cognition questionnaire. Immediately after reading an excerpt from a commonly used diabetes pamphlet, they could recall an average of only eight of the 108 ideas in it. Readers seldom monitored their comprehension. Also, the topics that they thought were important differed from the topics that a physician thought were important. Many readers lacked reading skills, but those with high need for cognition and higher vocabulary scores recalled more topics. Even with an appropriate reading level, text characteristics that could hinder comprehension included lack of organization and clarity.

A randomized, double-blind, placebo-controlled trial to evaluate the effect of enalapril in patients with clinical diabetic nephropathy.

It is unknown if the antiproteinuric effect of angiotensin-converting enzyme (ACE) inhibitors reflects attenuation in the rate of progression of diabetic nephropathy. We report the results of a randomized, double-blind clinical trial designed to evaluate the longitudinal (18-month) effect of the ACE inhibitor, enalapril (5 to 40 mg/d), versus a placebo on 24-hour urinary protein excretion and on the rate of progression of renal disease in 33 patients with clinical diabetic nephropathy. Systemic blood pressure was controlled throughout the trial with conventional antihypertensive drugs. Glomerular filtration rate (GFR), determined by Tc99mDTPA renal clearance, and urinary protein excretion were monitored at 3-month intervals. Enalapril, in contrast to placebo therapy, was associated with an initial (40%) and sustained (33%) decrease in urinary protein excretion. Patients randomized to both enalapril or placebo experienced mean decreases in GFR, from 1.01 mL/s/1.73 m2 (61 mL/min/1.73 m2) to 0.85 mL/s/1.73 m2 (51 mL/min/1.73 m2), and from 1.06 mL/s/1.73 m2 (64 mL/min/1.73 m2) to 0.97 mL/s/1.73 m2 (58 mL/min/1.73 m2), respectively. Eleven of 18 patients (61%) randomized to enalapril, and 10 of 15 (66%) patients randomized to placebo, had a decrease in GFR; their rates of progression were -1.18 mL/min/1.73 m2/mo and -1.00 mL/min/1.73 m2/mo, respectively. In the absence of changes in blood pressure, the addition of an ACE inhibitor to patients with clinical diabetic nephropathy could not be shown to confer a unique renal protective effect. A prolonged decrease in 24-hour protein excretion could not be shown to predict attenuation in the progression of established clinical diabetic nephropathy.

Hypersensitivity of diabetic human platelets to platelet activating factor.

Platelet activating factor (PAF) stimulated aggregation and [32P]-phosphatidic acid (PA) production was compared in normal and diabetic human subjects in platelet rich plasma. The concentration of PAF for half maximal (50%) aggregation of normal and diabetic platelets was 50 nM and 8 nM, respectively. PAF stimulated [32P]-PA production (a metabolite of phospholipase C pathway) was also greater in the platelets from diabetic subjects. This [32P]-PA production was inhibited by the PAF receptor antagonists SRI-63441 and SRI-63675. When the levels of glycosylated hemoglobin (HbA1c) were compared with the PAF stimulated [32P]-PA production a significant relationship was observed. These studies have demonstrated for the first time that diabetic human platelets show hypersensitivity to PAF in both aggregation and [32P]-PA production compared to normal subjects. This may be a result of some modification in phospholipid turnover mechanism and is receptor mediated. Further, the relationship of the degree of aggregation and [32P]-PA production to the level of HbA1c suggest that the insulin deficiency may contribute to these effects.

Effect of a microcomputer-based registry on adult immunizations.

A survey of patients attending the Cosmopolitan International Diabetes Center showed that one third of those born prior to 1935 did not know their immunization status, and only 56% of this group remembered ever receiving tetanus vaccine. In contrast, of those born after 1935, 98% gave a history of being vaccinated for tetanus, either as a child (76%) or as an adult (22%). Eight of the 35 patients who could not remember or denied receiving pneumococcal vaccine had in fact received it. Most patients could remember whether and when they had received influenza vaccine. A microcomputer-based registry was used to generate summaries of clinical information at each patient visit. These summaries included prevention-related items. There was a three- to five-fold increase in immunization rates when the dates of the most recent vaccinations were prominently displayed on the summary at the time of each visit.

Response to platelet-activating factor in human platelets stored and aged in plasma. Decrease in aggregation, phosphoinositide turnover, and receptor affinity.

Human platelet concentrates were stored in polyolefin bags at 22 to 24 degrees C on a horizontal shaker for up to 8 days. At different intervals, aliquots of platelet-rich plasma (PRP) were removed aseptically and five variables, i.e., platelet counts, morphology, platelet-activating factor (PAF)-stimulated aggregation, phosphoinositide turnover, and [3H]PAF binding to platelet receptors, were studied. The number of platelets did not change during the 8 days of storage. Scanning electron microscopy of the platelets revealed a gradual morphologic change from biconcave flat discs to irregular, crenated forms. The PAF-induced aggregation of platelets declined with time of storage. A decrease to 50 percent of the Day 1 aggregatory response to PAF was evident on Day 2, and there was a further decline to about 20 percent by Day 6. Similarly, PAF receptor-coupled phosphoinositide turnover, as monitored by 32P incorporation into individual phosphoinositides, decreased dramatically with storage. After 2 to 3 days of storage, the phosphoinositide turnover was reduced to 50 percent of the original response, and it continued to decline to about 25 percent of original response by Day 5 or 6. The binding of [3H]PAF to washed human platelets indicated subtle changes between Days 2 and 4, which became more noticeable by Day 6. These results have raised the possibility of changes in the number of the receptors and/or their affinity for the ligand during storage. We conclude that although the number of platelets was maintained during storage for 8 days, a general deterioration of their responses to PAF occurred at the levels of cell surface receptor, transmembrane signaling (phosphoinositide turnover), and response (aggregation).

The liver and circulating thyroid hormones.

The liver plays a major role in modifying the total circulating hormone concentrations of thyroxine and triiodothyronine by secretion and degradation of carrier proteins. It also is a major site of peripheral conversion, degradation, and excretion of thyroid hormones. We review the liver's role in thyroid hormone physiology and summarize the changes in circulating thyroid hormone concentrations in various liver diseases.

Myotonic response induced by inhibitors of cholesterol biosynthesis.

Steroid inhibitors of cholesterogenesis containing nitrogen-substituted side chains induced electromyographic myotonia in rats. Cholesterol reduction or desmosterol accumulation, per se, did not cause myotonia, and cholestrol feeding prevented drug-induced myotonia. Desmosterol accumulation in combination with a specific drug effect may cause the observed myotonia.