Association of differing dietary, metabolic, and clinical risk factors with microvascular complications of diabetes: a prevalence study of 503 Mexican type II diabetic subjects. II

The overall prevalences of microvascular complications and their association with dietary, clinical, and metabolic characteristics have been studied in 503 Mexican type II diabetic subjects. Average daily dietary intakes were 1866 kcal, 46.5% as carbohydrate, 13.7 mmol cholesterol, 8.7 g fiber, and a polyunsaturated/saturated fat ratio of 0.98. Prevalence rates of microvascular and metabolic complications were as follows: background retinopathy 12.3%, exudative retinopathy 24.2%, proliferative retinopathy 8.1% (1% blind, 4% able to read large print only), 9.1% of patients had cataract, 15.9% nephropathy, and 40.8% peripheral neuropathy. In addition, 3.6% had experienced transient lower motor neuron facial paralysis and 0.2% oculomotor paralysis. Patients with retinopathy had a longer mean duration of diabetes, were less obese at the time of examination, and had higher initial and mean blood pressures and higher mean fasting blood glucose levels when compared with those without retinopathy. Similar differences were observed between groups with and without nephropathy except that mean blood glucose levels were similar in the two groups. The presence of peripheral neuropathy was associated with longer duration of diabetes, less obesity, higher mean blood pressure and mean blood glucose levels, and lower hemoglobin concentration. Patients treated with diet alone had significantly lower prevalences of all three microvascular complications but they also had significantly shorter duration of diabetes and lower mean blood glucose levels. However, multivariate analyses on the subgroup of 360 patients who had repeated fasting blood glucose measurements for at least 5 yr demonstrated associations between retinopathy and duration of diabetes, mean blood pressure and mean blood glucose, and percent calories from carbohydrate.(ABSTRACT TRUNCATED AT 250 WORDS)

Association of differing dietary, metabolic, and clinical risk factors with macrovascular complications of diabetes: a prevalence study of 503 Mexican type II diabetic subjects. I

Macrovascular and microvascular complications of diabetes may be associated with different environmental factors. To investigate this further, a prevalence study of 503 Mexican type II diabetic subjects was carried out while their patterns of nutrition were constrained by government food subsidies. Average daily dietary intakes were 1866 kcal; 46.5% as carbohydrate, 13.7 mmol cholesterol, 8.7 g fiber, and a polyunsaturated/saturated fat ratio of 0.98. With respect to macrovascular disease, 49.3% of patients had evidence of peripheral vascular disease, and 21.6% myocardial ischemia, 6.0% angina, 10.8% EKG evidence of ischemia, 4.8% EKG evidence of myocardial infarction. Only 1.2% (six patients) had a clear history of completed stroke, and all were hypertensive. Six patients had also undergone amputations for diabetic gangrene. Tabulation of the means of clinical characteristics according to presence or absence of myocardial ischemia showed that higher cholesterol, calorie, and fat intake, higher mean blood pressure, higher serum cholesterol, and serum triglyceride levels were found in those with myocardial ischemia. Patients with peripheral vascular disease were more commonly smokers. Stepwise logistic regression revealed significant positive associations between myocardial ischemia and dietary cholesterol, serum cholesterol, and mean blood pressure. In contrast, the presence of peripheral vascular disease was significantly related only to smoking and retinopathy. There were no associations between macrovascular complications and duration of diabetes in the multivariate analysis, and they occurred with equal frequency in men and women. Prospective studies of atherosclerosis in maturity-onset diabetes should assess and seek to modify dietary cholesterol, serum cholesterol, and hypertension.

Prospective study of tympanosclerosis developing after grommet insertion

Grommets have been used as a treatment for middle-ear effusions since their introduction by Armstrong in 1954. However, it is now accepted that the presence of a grommet in a tympanic membrane is associated with the development of tympanosclerosis in that membrane. Furthermore, it has been shown that this is a progressive phenomenon and that the incidence increases with time to as much as 65 per cent at 3 to 4 years after grommet insertion (Mawson and Fagan, 1972; Tos and Poulsen, 1976). Initially it was suggested that the development of tympanosclerosis might be due to the middle ear disease rather than to the grommet (McKinnon, 1971). However, most recent studies have found that, in bilateral cases of effusion, tympanosclerosis develops more frequently in ears with a grommet than in those without (Brown, Richards and Ambegaokar, 1978; Lildholt, 1979). This prospective study was designed to show the development of tympanosclerosis in the tympanic membrane of children treated for bilateral middle-ear effusions and to elicit any factors from the clinical history and operative technique which might be associated with the pathogenesis of the complication.

Prospective evaluation of metabolic bone disease after jejunoileal bypass

Twenty-eight patients undergoing jejunoileal bypass for morbid obesity were studied prospectively for alterations in mineral metabolism and the development of metabolic bone disease. Eleven additional patients were examined for long-term complications. Serum 25-hydroxyvitamin D and fractional calcium absorption were depressed during the first 2 yr after bypass but normalized after this period. Serum parathormone remained normal. Mild osteomalacia was identified in 12% of subjects by histomorphometric analysis of undecalcified biopsy specimens. Osteomalacia was asymptomatic and could not be reliably diagnosed by noninvasive tests. Repeat biopsies demonstrated histologic improvement in 2 individuals followed serially. Improvement was not clearly related to vitamin D therapy. Abnormalities in mineral appositional rates and mineral maturation were identified in several additional patients. Studies in the long-term group did not indicate inexorable progression of metabolic bone disease. Although intestinal bypass produced several abnormalities in mineral metabolism during the first 2 yr after surgery, a trend toward normalization was evident after the period, possibly related to adaptive responses in the intestine.

Mechanical arrangement of costal and crural diaphragms in dogs

To assess the mechanical arrangement of the costal and crural parts of the diaphragm, we studied changes in diaphragmatic length with piezoelectric crystals in 17 supine anesthetized dogs. During control resting inspiration, the crural part usually shortened more and earlier than the costal part. After phrenicotomy, the crural part always lengthened during inspiration, whereas the costal part shortened or lengthened. These interanimal differences disappeared after opening of the abdomen; the costal part then always lengthened during inspiration. During stimulation of one part, the relaxed nonstimulated part always lengthened. However, when compared with the relationship between length and transdiaphragmatic pressure (Pdi) obtained during passive deflation, the lengthening of the relaxed part during stimulation of either part was small. This difference between predicted and measured Pdi-length relationship decreased in magnitude as lung volume increased above functional residual capacity (FRC) and increased as residual volume was approached. These results indicate that 1) even during quiet breathing the diaphragm in the dog is not a single functional entity; 2) at FRC the costal and crural portions of the diaphragm behave as if they were mechanically arranged partly in parallel and partly in series; and 3) they gradually move into a pure mechanical series arrangement as lung volume increases.

Salutary effect of fall in abdominal pressure during diaphragm paralysis

To examine the mechanical effects of the fall in abdominal pressure (Pab) that occurs during inspiration in diaphragmatic paralysis, we studied lung inflation and rib cage expansion before and after the abdomen was opened in nine spontaneously breathing dogs with bilateral phrenicotomy . We measured Pab, tidal volume, and parasternal electromyographic (EMG) activity during quiet breathing and CO2-induced hyperpnea. In six dogs, we also measured changes in anteroposterior and transverse rib cage diameters, the resting length of the parasternal intercostal muscles, and the amount of shortening of these muscles during inspiration. Opening the abdomen caused a marked reduction in the fall in Pab during inspiration and invariably resulted in a decrease in tidal volume (mean decrease, 13%), which contrasted with marked increases in inspiratory rib cage expansion and in the amount of parasternal intercostal shortening. The procedure, however, did not affect the resting length or inspiratory EMG activity of the parasternals . These findings indicate that although the fall in Pab, which occurs during inspiration in diaphragmatic paralysis, causes paradoxical inward displacement of the ventral abdominal wall, it has a salutary effect on tidal volume. This phenomenon is probably due to the fact that the diaphragm is part of the abdominal wall.

Action of neck accessory muscles on rib cage in dogs

To investigate the action of the neck accessory muscles on the rib cage, we stimulated the sternocleidomastoid and the scalenus muscles separately in supine anesthetized dogs. Hooks screwed into the sternum and ribs were used to measure their axial displacements and the changes in anteroposterior (AP) and transverse (T) diameters of the rib cage. We found that the sternocleidomastoid and scalenus muscles, when they contract alone, cause a large axial displacement of the sternum and the ribs in a cephalad direction and expand the rib cage along both its AP and T diameters. Opening the abdomen increased the cephalad displacement of the ribs and the expansion of the lower rib cage, particularly along its T diameter, but reduced the increase in lung volume. These experiments indicate 1) that the action of the sternocleidomastoid and scalenus muscles on the rib cage is essentially the consequence of a rotation of the ribs' neck axes, resulting from the cephalad displacement of the ribs, and 2) that the fall in abdominal pressure, almost certainly by acting through the zone of apposition of the diaphragm to the rib cage, has a deflationary action on the lower rib cage, more markedly so on its lateral than its anterior wall. The experiments also suggest that the fall in abdominal pressure prevents the diaphragm from moving cephalad and aids the neck accessory muscles in inflating the lungs.

Eye injuries in organised sport in a rural area

Eye injuries in sport are a continuing preventable problem. An investigation into sport injuries in rural Ireland shows hurling to be the most dangerous pastime, and this is compared and contrasted with other local games. Forty-five consecutive injuries sustained in organised sport requiring admission to hospital over a 4-year period were studied. 40% were due to hurling. Over three-quarters of the 45 patients recovered 6/6 vision or better. The costs to the community of such eye injuries are discussed.

The nucleotide sequence of the HhaII restriction and modification genes from Haemophilus haemolyticus

We have determined the nucleotide sequence of a cloned 1710-bp segment of Haemophilus haemolyticus DNA which contains the HhaII restriction (r) and modification (m) genes. The m gene is 513 bp in length and the rgene is 681 bp in length. Both are in the same reading frame, being separated by a 21-bp region. A ribosome-binding site is identified in front of each gene, but no Haemophilus promoter is apparent on the cloned fragment. Transcription originates from a plasmid promotor and proceeds in the direction m to r.

Golgi membranes contain an electrogenic H+ pump in parallel to a chloride conductance

Rat liver Golgi vesicles were isolated by differential and density gradient centrifugation. A fraction enriched in galactosyl transferase and depleted in plasma membrane, mitochondrial, endoplasmic reticulum, and lysosomal markers was found to contain an ATP-dependent H+ pump. This proton pump was not inhibited by oligomycin but was sensitive to N-ethyl maleimide, which distinguishes it from the F0-F1 ATPase of mitochondria. GTP did not induce transport, unlike the lysosomal H+ pump. The pump was not dependent on the presence of potassium nor was it inhibited by vanadate, two of the characteristics of the gastric H+ ATPase. Addition of ATP generated a membrane potential that drove chloride uptake into the vesicles, suggesting that Golgi membranes contain a chloride conductance in parallel to an electrogenic proton pump. These results demonstrate that Golgi vesicles can form a pH difference and a membrane potential through the action of an electrogenic proton translocating ATPase.

Mechanical action of the intercostal muscles on the ribs

The external and internal interosseous intercostal muscles were separately stimulated at end-expiratory lung volume in anesthetized dogs. These muscles were all found to elevate the ribs into which they insert. By attaching weights to the ribs, it was determined that the nonlinear compliance of the ribs was responsible for this phenomenon.

The proton translocating ATPase responsible for urinary acidification

H+ secretion by the turtle urinary bladder is produced by a proton pump located in the luminal membrane. We show that a microsomal fraction of these cells contains an electrogenic proton translocating ATPase that is inhibited by dicyclohexylcarbodiimide but not oligomycin or vanadate. On a sucrose density gradient, this ATPase co-migrated with luminal membranes labeled with concanavalin A, but was separate from a lysosomal marker. This enzyme is therefore the H+ ATPase that causes urinary acidification.

Chest wall mechanics in dogs with acute diaphragm paralysis

To investigate the action of the inspiratory intercostals, we studied the patterns of rib cage and abdominal motion during tidal breathing in eight dogs before and after bilateral phrenicotomy. Hooks screwed into the sternum and the ribs were used to monitor the anteroposterior and transverse diameters of the rib cage and the axial displacements of the sternum and the ribs. In all animals, we found that during tidal inspirations performed with the inspiratory intercostals alone, 1) the rib cage moved outward while the abdomen moved inward; 2) the rib cage was displaced near its relaxation curve (defined by a plot of its transverse vs. anteroposterior diameter) but expanded more in its transverse than in its anteroposterior dimension; and 3) the ribs in the midaxillary line moved cephalad, whereas the sternum was displaced caudally. Additional experiments performed on four dogs demonstrated that contraction of the parasternal intercostals was responsible for the inspiratory caudal displacement of the sternum. These findings indicate that in the dog, 1) the inspiratory intercostals act essentially on the lateral walls of the rib cage, and 2) those of the parasternal area produce a caudal displacement of the sternum. In addition, they suggest strongly that the axial displacement of the sternum constitutes an additional degree of freedom of motion of the rib cage and that contraction of the neck accessory muscles is mandatory for the sternum to be displaced in a cephalad direction during inspiration.

Gas mixing in the lungs of dogs and pigs

We performed single breath washouts in 14 dogs and 4 pigs using a gas mixture containing 5% helium (He) and 5% sulphur hexafluoride (SF6) with, and without, an end inspiratory breathhold. In dogs, the slope of the alveolar plateau was steeper for SF6 than for He, the difference decreasing after 20 sec of breathholding. In contrast, in pigs there was no difference between the two slopes although both were steeper than in dogs. Following a 15-sec breathhold, both slopes decreased, that of the He plateau becoming significantly flatter than that for SF6. Furthermore, the expirate became relatively SF6 enriched. The results indicate that in pigs the mechanism responsible for the sloping alveolar plateau is not diffusion dependent, and hence cannot be due to 'stratification'. Neither do the results support diffusive interaction within an asymmetrical acinus as a basis for the slope. Our findings suggest that the latter is due to sequential emptying of relatively large units subtended by a branch point in which gas transport is entirely convective.