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Biomedical subjects

X Navarro

Publications and source records attributed to X Navarro.

At least 73 records · Page 4Linked to original sources
PubMed1991

Evaluation of thermal and pain sensitivity in type I diabetic patients.

Thermal sensitivity was studied in 280 type I diabetic patients and in 75 control subjects. Warm and cool thresholds, temperature sensitivity limen (difference between warm and cold thresholds, TSL), and hot and cold pain thresholds were quantitated on the skin of the index finger, hand, foot and medial calf. The diabetic group had mean values that were significantly different from controls in all variables except the pain thresholds in the upper extremity. TSL was the most sensitive parameter, being abnormal in 57, 63, 79 and 78% of patients in the four skin sites tested. Hot pain sensitivity was abnormal in 37, 21, 39 and 26% of patients in the same sites. Thermal sensitivity abnormalities were more frequently observed than abnormalities in motor and sensory nerve conduction studies. Thermal tests correlated with the duration of the diabetes, although there were abnormalities at all stages of the disease. The results show that diabetic neuropathy has a variable presentation in different types of nerve fibres.

Adolescent↗
PubMed1990

Effects of pancreatic transplantation on diabetic neuropathy.

Reestablishment of the euglycemic state by successful transplantation of the pancreas might halt or reverse diabetic neuropathy. To test this possibility we evaluated neurologic function by clinical examination, nerve conduction studies, and autonomic-function tests in patients with insulin-dependent (Type I) diabetes mellitus before and after successful pancreatic transplantation. Sixty-one patients were studied before and 12 months after transplantation, 27 again after 24 months, and 11 again after 42 months. A control group of patients with Type I diabetes treated with insulin underwent the same studies at similar intervals--48 patients before and after 12 months had elapsed, 21 again after 24 months, and 12 again after 42 months. In the control group, neuropathy tended to worsen during the follow-up period. The scores on the clinical examination indicated increased impairment after 12 months. Composite indexes of the degree of abnormality found on neurophysiologic testing of the function of peripheral motor, sensory, and autonomic nerves indicated decreased autonomic function after 12 months. The examination score and the three index values worsened slightly but not significantly in the patients followed for 24 and 42 months. In contrast, in the patients who had received pancreatic transplants, the neuropathy tended to improve. There was significant improvement in the motor and sensory indexes 12 months after transplantation and in the sensory index 24 months after transplantation. The other measures improved slightly but not significantly at these times, as did all four measures in the patients studied 42 months after transplantation. We conclude that the progression of diabetic polyneuropathy may be halted through the restoration of a euglycemic state by successful pancreatic transplantation.

Adult↗
PubMed1990

The effect of a conditioning lesion on sudomotor axon regeneration.

The effects of a conditioning lesion on the rate of sudomotor axon regeneration were judged by the recovery of sweat gland (SG) secretion after cholinergic stimulation. Three groups of mice were given a conditioning lesion by crushing the sciatic nerve at mid-thigh 4, 7, and 14 days before a test lesion. A 4th group received a conditioning crush of the tibial nerve at the ankle 7 days before the test lesion. Control mice had a single test lesion. SG reinnervation in control mice began 19 days after the test lesion, and was functionally complete by 41 days. In groups with the conditioning lesion 4, 7, and 14 days before the test operation, the first reactive SGs reappeared at 16, 15, and 16 days respectively after the test lesion, and maximal recovery occurred by 33, 32, and 39 days. In mice with the distal conditioning lesion, reinnervation began at 19 days and was maximal by 36 days. In summary, a nerve conditioning lesion placed from 4 to 14 days prior to and at the same site as a test lesion significantly accelerated the growth rate of the fastest regenerating unmyelinated sudomotor axons and reduced the time until most SGs were reinnervated. A more distally placed test lesion reduced the interval for recovery.

Adaptation, Physiological↗
PubMed1990

Changes in sudomotor nerve territories with aging in the mouse.

This study evaluates sudomotor function in the hindpaw of young and aged mice. Sweating was stimulated by pilocarpine injection and by electrical stimulation of the sciatic, tibial, peroneal, sural and saphenous nerves. The number of responsive sweat glands of the paw was determined by the silicon mold technique. The results obtained provide evidence that the number of functioning sweat glands of the hindpaw tended to decrease in aged mice. The peripheral sudomotor territories and the complement of sweat glands for individual nerves declined slightly with age. Moreover, the number of sweat glands responsive to cholinergic stimulation was decreased when compared with the number responsive to electrical stimulation of the sciatic nerve in aged mice. These and previous observations suggest that the number of sudomotor axons in the peripheral nerve, as well as their capabilities for compensatory reinnervation of sweat glands by regeneration and by sprouting, is reduced with aging.

Aging↗
PubMed1990

Evaluation of duodenogastric reflux in gallstone disease before and after simple cholecystectomy.

Duodenogastric reflux (DGR) has been suggested as an etiopathogenic factor in gastric disease in patients with gallstones. We evaluated the DGR levels in 15 patients before and after simple cholecystectomy for gallstones and compared the results with those of 15 healthy subjects. Gastric juice was obtained by continuous nasogastric suction for 24 hours. The bile acids (BA) present in the samples were quantified by thin-layer chromatography and in situ spectrofluorometry. The mean BA concentration for the control subjects was 2.25 mumol reflux/hour, whereas the mean value for the 15 patients with cholelithiasis was 8.86 mumol reflux/hour before cholecystectomy and 24.55 mumol reflux/hour after cholecystectomy. Five patients did not have detectable BA in the gastric juice in both analyses; the remaining 10 patients showed a significant increase in the BA after surgery. From these data, we conclude that gallstone disease is not always accompanied by an increased DGR. However, in patients in whom DGR is present, its level is higher than in control subjects and increases significantly after cholecystectomy. This is probably due to the greater amount of bile in the duodenum that may reflux through an incompetent pyloric channel.

Adult↗
PubMed1990

Bile reflux in postoperative alkaline reflux gastritis.

This study evaluates enterogastric reflux (EGR) levels in patients with and without symptoms of postoperative alkaline reflux gastritis (PARG) after gastric surgery. The bile acids (BA) present in the gastric juice were quantified by thin-layer chromatography and spectrofluorometry. The mean BA concentration for controls was 2.25 mumol reflux/hour, for 15 asymptomatic patients 47.94 and for 15 patients with symptoms of PARG 125.79. After biliary diversion by a Roux-en-Y anastomosis in the latter, their BA in 13 of these patients after surgery, and relapsed in only one during a 4-year follow-up. The remaining two patients had the lowest preoperative BA levels in this group. These results indicate that EGR is increased after gastric surgery more markedly indicated that EGR is increased after gastric surgery more markedly in patients with symptoms of PARG, and that patients who have high levels of EGR (more than 80 mumol BA reflux/hour) clearly benefit from biliary diversion.

Adult↗
PubMed1990

Influence of pancreas transplantation on cardiorespiratory reflexes, nerve conduction, and mortality in diabetes mellitus.

Cardiorespiratory reflexes (CRR) were studied by measuring heart-rate variation during 6 breaths/min respiration and a Valsalva maneuver in 232 insulin-dependent diabetic subjects. Abnormalities were found in 175 patients. During a 7-yr follow-up, 41 (23.4%) patients with abnormal and 2 (3.5%) with normal CRR tests died. The mortality rates of diabetic patients with abnormal autonomic function tests were 17% at 2.5 yr, 33% at 5 yr, and 40% at 7 yr, significantly higher (P less than 0.002) than in patients with normal tests (rates of 4.6, 4.6, and 13.8% at the respective intervals). Nerve conduction studies (NCS) were indicative of somatic neuropathy in 148 of 205 patients. Mortality rates were higher in patients with abnormal NCS than in those with normal results (P less than 0.025). Among patients with abnormal autonomic function, patients with a functioning pancreas transplantation (PTx) had better survival rates than patients with a failed PTx (P less than 0.005) and, on long-term follow-up, better rates than patients without PTx. Similar results were found comparing the same group of patients who had abnormal NCS.

Adult↗
PubMed1989

Sympathetic sudomotor function in diabetic neuropathy.

Sympathetic nerve function was studied by the Silastic mold technique and by evaporimetry in the hand and the foot in 357 type I diabetic patients. The number of active sweat glands was below normal in 24% of patients in the hand and in 56% in the foot, while the sweat evaporation rate was low in 17% and 40% of patients, respectively. Computerized analysis of the molds, which allowed automatic sweat gland counts and estimations of the secretion volume of each sweat gland, detected abnormalities in 36% and 60% of patients. The Silastic imprint technique was found to be a sensitive test for detection of sympathetic nerve involvement, even in asymptomatic patients with normal clinical and nerve conduction examinations. Its sensitivity and accuracy has been enhanced by the computerized analysis of the molds.

Adolescent↗
PubMed1989

Small nerve fiber dysfunction in diabetic neuropathy.

Sensory and autonomic small nerve fiber function was studied in 142 type I diabetics and 45 control subjects. Thermal sensitivity (TS), hot pain sensitivity, and the activity of sweat glands (SGs) were quantitated on the dorsum of the hand and the foot. TS was abnormal in 86% of patients in the foot and 66% in the hand. TS was more sensitive than the hot pain threshold, the number of pilocarpine activated SGs, or the amount of sweat secreted, all of which were abnormal in about 50% of patients for the foot and less than 25% in the hand. Thermal and sweating tests correlated significantly with the scores of abnormal temperature and pinprick sensation obtained by physical examination but not with the duration of the diabetes. TS was also correlated with motor and sensory nerve conduction parameters, but SG number was not. The results indicate that diabetic neuropathy has a variable presentation in different types of nerve fibers.

Adolescent↗
PubMed1989

Sweat gland reinnervation by sudomotor regeneration after different types of lesions and graft repairs.

Clinical and experimental investigations have shown that recovery of motor and sensory functions after a nerve lesion varies with the type of lesion and the repair technique. We report a study on regeneration of sudomotor axons to sweat glands (SGs) in the mouse paw following different sciatic nerve injury procedures: freezing, crushing, and sectioning. After sectioning, repair was by primary suture or by grafting with the resected section or with conduits of plastic or collagen. Successful regeneration was marked by the reappearance of SG reactivity to pilocarpine. After a freezing or crushing lesion, SGs activated by pilocarpine reappeared by 17 days postoperation and then increased progressively in number until the preoperative number of SGs were again active at 41 days. Cutting the nerve followed by primary repair resulted in a short delay and a significant deficiency in reinnervation. Results obtained with a graft of a segment of resected nerve were similar to primary repair after nerve section and better than when grafts of plastic or collagen tubes were used. This suggests that substances provided by the grafted nerve segment and the type of conduit provided play important roles in the regeneration of unmyelinated axons.

Animals↗
PubMed1989

Long-term survival following kidney transplantation in 100 type I diabetic patients.

Between December 1966 and April 1978, 265 uremic patients with type I diabetes received primary renal allografts at the University of Minnesota. One hundred of the diabetic patients were alive with a functioning graft 10 years after transplantation. The actual 10-year patient and primary graft functional survival rates overall were 40% and 32%, respectively. For recipients of HLA-identical sibling (n = 45), mismatched living-related (n = 121), and cadaver donor grafts (n = 99), the actual 10-year patient survival rates were 64%, 33%, and 36%, respectively, and the actual 10-year graft functional survival rates were 62%, 28%, and 22%, respectively. The differences in patient and graft survival rates between HLA-identical graft recipients and recipients of mismatched related and cadaver grafts were significant (P less than 0.001). Of the 100 patients who survived into a second decade, at 15 years posttransplant 51% were alive, and 41% had functioning grafts. For recipients of HLA-identical sibling, mismatched living-related donor grafts, and cadaver donor grafts who survived 10 years, 47%, 57%, and 43%, respectively, were alive at 15 years, and 31%, 45%, and 43%, respectively, had functioning grafts. For recipients who made it to the second decade, patient and primary graft survival rates thereafter were not statistically different by donor source. Twenty-three patients died in the second decade after transplantation, 10 of cardiovascular disease. Twenty-five patients lost graft function in the second decade, 19 from death with a functioning graft. In regard to diabetic complications, recurrence of diabetic nephropathy was common, but only two patients lost graft function solely for this reason. In 21 patients (42 eyes) followed prospectively for 10 years, visual acuity deteriorated in 26%, was stable in 64%, and improved in 10% of eyes. Neurophysiological test results indicated that correction of uremia does not stop the progression of diabetic neuropathy in recipients of kidney transplants alone. Even without cyclosporine, nearly two-thirds of recipients of HLA-identical kidney grafts, more than one-quarter of recipients of mismatched living-related donor grafts, and more than one-fifth receiving cadaver grafts enjoyed an extension of life for more than 10 years.

Age Factors↗
PubMed1989

Red blood cell fatty acids in multiple sclerosis.

The fatty acid (FA) composition of each phospholipid constituent of the red blood cells (RBC) was analyzed, by thin-layer and gas chromatography techniques, in 61 multiple sclerosis (MS) patients and 61 normal subjects, in whom the plasma lipid FA composition had previously been studied. The MS patients showed a significant decrease in the proportions of linoleic and arachidonic acids in most phospholipids, with a compensatory increase of saturated FA. Correlations between FA percentages in plasma and cell lipids demonstrated abnormalities in the MS patients, suggestive of a disturbance in the exchange between these compartments. The alterations reported in plasma and RBC in the MS patients are consistent with a relative deficiency of essential FA.

Arachidonic Acids↗
PubMed1989

Physiological and clinical correlates of cardiorespiratory reflexes in diabetes mellitus.

Cardiorespiratory reflexes (CRRs) were studied by measuring heart-rate (HR) variation during 6 breaths/min respiration (delta R6) and Valsalva maneuver (VR) in 145 healthy and 417 type I (insulin-dependent) diabetic subjects. HR variation with breathing at 12 breaths/min and ventilatory response to hypercapnia/hypoxia were measured in fewer subjects. CRR results were compared with symptoms of autonomic dysfunction, the neurological examination, nerve conduction studies, and quantitative sweat testing. The objective was to compare the sensitivity of various methods of characterizing diabetic patients and to use this information when staging patients for clinical therapeutic trials. CRR responses were age dependent in both populations. Either delta R6 or VR was abnormal in 74% of diabetic patients, delta R6 being more sensitive. CRRs correlated well with the presence of symptoms of autonomic dysfunction, abnormalities on the neurological examination, results of nerve conduction studies, and sweating activity in the feet of the same patients. However, both CRRs and sweating were abnormal in a high proportion of patients without any clinical manifestations of neuropathy. The ventilatory reflex response to moderate hypercapnia/hypoxia was also measured. It was normal in most of the diabetic patients tested, including many with severe reduction of CRRs. We conclude from the combined results of CRR, ventilatory response, and other studies that the causative factors for abnormal CRR may not be confined to the vagus nerves, and that in most instances, the depressed CRR may be due to a decrease in the efficacy of sensorimotor nerve conduction around the reflex arc.

Adolescent↗
PubMed1989

[Determination of duodenogastric reflux by quantification of bile acids in the gastric juice].

The existence of duodeno-gastric reflux was evaluated in a group of 15 healthy subjects, in fasting and for 24 hours. The assessment of duodeno-gastric reflux was made by quantitation of the bile acids (BA) present in the gastric juice. The individual free and conjugated BA were separated and quantified by means of thin-layer chromatography and in situ spectrofluorometry. In 7 of the subjects studied no BA were detected, and in the other 8 subjects the BA levels were below 6 mumol reflux/hour. There were no free BA detected in any of the subjects. The levels of BA in gastric juice increased progressively with age, but there were no differences between sex. The chromatographic technique used is highly sensitive for the analysis of BA in biological samples. The study of BA in the gastric juice provides a quantitative and reliable assessment of the degree of duodeno-gastric reflux.

Adult↗
PubMed1988

Effect of age on collateral reinnervation of sweat glands in the mouse.

This study demonstrates that the number of sweat glands (SGs) innervated by individual peripheral nerves in the mouse hind paw decreases with aging but the ability for reinnervation by collateral sprouting is maintained throughout life. In one experiment, the saphenous, peroneal and tibial nerves were cut and tied, denervating all SGs of the hind paw except those receiving axons from the intact sural nerve. In another, the saphenous was the only nerve left intact. The initial number of SGs supplied only by the single intact nerve was significantly higher in young adult than older mice. The capacity of the sural and saphenous nerves to collaterally reinnervate the denervated SGs was followed by serial testing for the return of sensitivity to pilocarpine stimulation. Collaterally reinnervated SGs appeared during the second and third weeks postoperation adjacent to already active SGs, thereby increasing the total sweat area of the intact nerve, and its SG number about 3, 2 and 5 times for the sural, and 8, 2 and 2 times for saphenous nerve, in young, adult and old animals respectively. Reinnervation was slightly faster and the degree of extension greater in young than adult mice, and the degree of extension was decreased in older mice. These observations suggest that the number of sudomotor axons in the peripheral nerve, as well as their capacity for collateral reinnervation, is reduced with aging.

Aging↗
PubMed1988

Effect of age and maturation on sudomotor nerve regeneration in mice.

This study demonstrates that regeneration of unmyelinated sudomotor axons in mice becomes progressively slower during aging. Identical lesions were made in mice aged 0, 2, 4, 6, 7, 24 and 60 weeks. The peroneal, sural and saphenous nerves were cut and tied to prevent regeneration. The sciatic nerve was then frozen at the thigh, leaving the hind paw completely denervated. By 7 days, sweat glands (SGs) of the paw had ceased sweating after pilocarpine injection. Subsequent regeneration of sudomotor axons was judged by the rate of return of pilocarpine sensitivity. SGs in the hind paws of normal newborn mice did not sweat at birth. Cholinergic stimulation first activated sweating at 13 days of life. The number of responsive SGs increased progressively to reach the adult level by 30 days. In one-week-old mice, whose sciatic nerve had been sectioned, the SG response to cholinergic stimulation was very delayed in time and reduced in number. Sweat glands of young mice, between 2 and 4 weeks of age, regained cholinergic sensitivity at a faster rate than mature animals and attained normal SG counts. Throughout a broad intermediate range of age in adulthood (7-24 weeks), the rate of sudomotor nerve regeneration was the same, but in older mice (60 weeks) it was slower and less complete.

Aging↗