No description available.

No description available.

No description available.

No description available.

No description available.

No description available.

The object of this study was to investigate the effects of an aldose reductase inhibitor, sorbinil (Pfizer inc), in relation to some of the biochemical, structural and functional changes associated with diabetic nerves. An animal model, the streptozotocin-induced diabetic rat was used and the following studies were performed: Motor nerve conduction velocity (MNCV) was measured in the tibial nerve over a 6 month period. A group of rats were examined at the onset of the experiment (OC) to provide a baseline for comparison to all other groups. Age matched control (AMC) animals showed a 13% increase in MNCV during the first 3 months of the experiment with little increase thereafter. The diabetic animals (DC) did not significantly differ over the experimental period from the OC animals and were thus slower conducting than the corresponding AMC group. Administration of sorbinil (25 mg/Kg) to rats from the onset of diabetes had no effect on MNCV by 3 months but had normalised values by 6 months. Nerve glucose, sorbitol, fructose and myo-inositol levels were examined by GLC. Sorbinil had no effect on nerve glucose values but prevented the 10-fold increase in nerve sorbitol values observed with the DC animals. Sorbinil partially normalised nerve fructose values after 3 months of treatment and fully normalised them after 6 months. Myo-inositol (MI) levels showed a 45% reduction by 3 months of diabetes but were normal after 6 months. Sorbinil showed a tendency to restore the reduced MI values by 3 months. Morphometric profiles were examined in the tibial nerve. Axon areas demonstrated a 14% reduction at both 3 and 6 months of diabetes while myelin areas were increased by 13 and 22% respectively. Sorbinil treatment allowed normal axon growth and normalised myelin areas. MNCV was examined in the tibial and gastrocnemius nerves. As above, diabetes prevented the normal MNCV maturation in the tibial nerve. Sorbinil administration (25 mg/Kg) to rats initially diabetic for 2 months, was ineffective in restoring MNCV in the tibial nerve though a partial recovery was observed after 4 months of treatment. MNCV in the gastrocnemius nerve of the DC animals continued to fall as the experiment progressed, reaching a 33% reduction below the OC animals by 3 months. A spontaneous recovery was observed thereafter. Sorbinil partially normalised MNCV in the gastrocnemius nerve after 1 month. These changes exactly paralleled the changes in nerve MI levels. Sorbinil reversed the already elevated nerve sorbitol levels after 1 month of treatment though nerve fructose levels were only partially normalised after 4 months. A morphometric evaluation of the triceps surae nerve (containing fibres to gastrocnemius and soleus muscles) after 4 months of the experiment demonstrated an 18% increase of myelin area in the DC animals. Axon areas were unaffected by diabetes. Sorbinil treatment for 2 months partially normalised myelin areas. Sorbinil administration at doses of 7.5, 12.5 and 25 mg/Kg to rats that had been diabetic for 2 months did not normalise MNCV in the tibial nerve. However, 12.5 and 25 mg/Kg produced a significant improvement in MNCV of the gastrocnemius nerve after 1 month of treatment. 7.5 mg/Kg had no effect in this nerve. All doses of sorbinil produced a trend towards reversing the already elevated nerve sorbitol levels, though 25 mg/Kg was effective after 1 month of treatment whereas 12.5 mg/Kg required 2 months. 7.5 mg/Kg did not fully normalise nerve sorbitol levels. Nerve fructose values remained elevated, though treatment with 25 mg/Kg of sorbinil produced a reduction towards normal values. All 3 doses partially normalised MI levels. For all DC groups, sciatic nerve water content was significantly elevated after a 1 month experimental period. Sorbinil treatment, either given from the induction of diabetes or given after rats were initially diabetic for 2 months, had only a small effect on water content and values remained elevated compared with the controls.

No description available.

The importance of soft tissue structures in the pathogenesis of diabetic complications in the hand and particularly the forefoot due to nerve damage or neuropathy has long been overlooked. This is partly due to the inability of most clinical techniques to examine tissue structures in vivo. Magnetic Resonance Imaging (MRI) provides a unique opportunity to study these tissues in detail. Through the use of a specially designed "targetted" radiofrequency coil, high-resolution imaging of the forefoot anatomy has been achieved. In addition to anatomical imaging, MRI has been used to give functional information about water dynamics in various tissue types, e. g. the fat pad and the muscles in the foot. The potential of this type of information to provide an insight into the severity and progression of diabetes has been investigated during this research work. In detail two patient groups with and without symptoms of neuropathy have been investigated. Deterioration of foot joints with a collapsed arch and intrinsic muscle wasting due to nerve damage were observed but more importantly several as yet unknown and unobserved phenomenon were also demonstrated. (i) At sites of maximum pressure resulting from neuropathic changes evidence of microhemorrhaging (or localised hemosiderin deposits) was observed through signal voids when using a gradient echo sequence. It is postulated that the occurrence of these voids is due to the paramagnetic iron core of the hemosiderin aggregate and therefore the signal from tissue in its proximity may be recovered with a spin echo sequence. (ii) The use of a Magnetisation Transfer (MT) sequence to provide functional information revealed a distinct change in MT activity deep within the fat pad of the foot at sites of maximum pressure. This is in contrast to the normal fat pad core which is MT inactive since its hydrophobic nature prevents the adsorption of free water. The fat pads of patients suffering from neuropathy showed various degrees of MT activity which hasbeen taken to indicate the presence of fibrotic material as a replacement for fat. This is consistent with current theories of the formation of neuropathic ulcers. The fibrotic tissue is likely to be the result of repetitive trauma to fat tissues leading to fibrosis where the condition of diabetes serves to catalyse its production via glycation and cross-linking of collagen. Histopathological examination of the fat pad tissues of similar patients, confirmed the presence of fibrosis. This is the first time that such a change in plantar fat pad tissue has been demonstrated in vivo. Further it was possible to correlate the extent of MT activity with disease severity. (iii) In an additional study of Limited Joint Mobility in the metacarpophalangeal (MCP) joints of the hand it was found that the cross-sectional area of the joint capsule reduced linearly with age for patients and controls and that there was no significant thickening relative to controls as postulated from work by others using plain radiographs

Objectives: The purpose of this medical thesis was to describe the clinical and neurophysiological features and to evaluate the health related quality of life (HR-QoL) in patients with cryptogenic polyneuropathy. We also wanted to investigate different occupational, and leisure time exposures as determinants for cryptogenic polyneuropathy, and to analyze whether polymorphisms for the null alleles of Glutathione S-Transferase Mu-1 (GSTM1), and Theta-1 (GSTT1), and a low activity genetic variation of epoxide hydrolase (EPHX) affect the risk of developing polyneuropathy. These genes were chosen because their enzymes are important in the metabolism of toxic compounds. Methods: The medical records of all patients aged 40–79 years with the diagnosis of cryptogenic polyneuropathy from 1993 to 2000 were analyzed, and data regarding clinical symptoms, laboratory findings, and neurophysiological findings at diagnosis were collected. 255 cases were found. When the medical records were reevaluated assessment to a protocol 168 patients remained as cryptogenic. Two validated instruments (SF-36 and EQ-5D) for measuring HR-QoL were sent to patients, and a reference group from the general population. Additional clinical information, and data on occupational, and leisure time exposure was obtained from postal questionnaires. Crude odds ratios (COR), and logistic regression odds ratios (LOR) were calculated for exposures with five or more exposed cases and referents taken together. We also tested for genetic polymorphisms of GSTM1 and GSTT1, and epoxide hydrolase exon three, EPHX*3. Results: 68% of the patients were men. The mean age at first symptom was 61 years and at diagnosis 64 years. Distal numbness was the most common symptom, but pain, pedal paresthesias, and impairment of balance were also common. The most common clinical findings were decreased or lost proprioception or sense of vibration (80%), and loss of ankle jerks (78%). Neurography showed mixed sensorimotor polyneuropathy of axonal or mixed axonal and demyelinating type. QOL was significantly affected concerning motor functions, with 42% of the patients reporting problems to walk, 3% having problems with daily activities, and 85% were suffering from pain. Mental health was preserved. Mobility was declining with increasing age, but was not affected by disease duration. Increased risks were found in men for occupational exposure to sulphur dioxide, xylene, methyl ethyl ketone, and herbicides and in women for occupational exposure to lead, nitrous oxide, and insecticides. Interaction between occupational and leisure time exposure were seen for several exposures. No significant correlation was found between GSTM1, GSTT1, and EPHX1 polymorphisms in patients with cryptogenic polyneuropathy compared with controls. A tendency, however, was seen for the GSTT1 null phenotype, which was enhanced among smokers compared to controls (OR 3.7). Conclusions: Cryptogenic polyneuropathy is a slowly progressive sensorimotor nerve lesion of mainly axonal type. Patients with cryptogenic polyneuropathy have a lower QOL compared to the general population, although mental health scores did not differ between the groups. Our results show that known determinants could be confirmed, but also some new appeared i.e. sulphur dioxide, hydrogen sulphide, fungicides, and vibrations in the feet. Moreover our results point to a synergistic effect of various exposures. Our hypothesis is that the GSTT1 null polymorphism may be related to an impaired metabolism of toxic substances and reactive oxygen that could lead to nerve damage in the peripheral nervous system. Our results are indicating that components in cigarette smoke might increase the risk of axonal neuropathy in genetically predisposed patients.