Embolisation of Ruptured Cerebral Aneurysms with Interlocking Detachable Coils in Acute Stage

Twelve cases of ruptured cerebral aneurysm were treated in acute stage with interlocking detachable coils (IDC, Target Therapeutics, Fremont, California) and the outcome was assessed.

IDCs were placed intra-aneurysm for intra-aneurysmal occlusion, or intra-artery for proximal occlusion. Cases: age 36–84 (mean; 60) y.o., 11 females and 1male; 1, 5, 4 and 2 patients were categorised (Hunt and Hess) as grades 1, 2, 3 and 4 respectively. An intra-aneurysmal occlusion in ten cases and a proximal occlusion in two were performed on day 1–11 (mean 4).

On angiograms and CT findings, the ruptured point seemed to have occluded in all cases. The occlusion rate was 100% in five cases, 95% in two, 90% in three, 80% in one, and less than 50% in one.

There were two cases of technical complication, one a coil migration and the other an aneurysmal perforation with IDC.

Their Glasgow Outcome Scale six months after embolisation was graded as good recovery in four cases, moderately disabled state in two, severely disabled state in one, and dead in five. Follow-up angiograms taken four to six months after embolisation showed an intra-aneurysmal coil compaction in five cases. Two of these were treated by a second embolisation or by neck clipping followed by aneurysmal resection, but another two were observed without any treatment and the last one died of rebleeding. Histological examination of the resected embolised aneurysm revealed slight organization around coils but no endothelialisation over the aneurysmal orifice.

In our experience, coil embolisation with IDC for acute ruptured aneurysm is a promising means of preventing rerupture during subacute stage.

Glucotoxic Mechanisms and Related Therapeutic Approaches

Neuropathy is the earliest and commonest complication of diabetes. With increasing duration of diabetes, frequency and severity of neuropathy are worsened. Long-term hyperglycemia is therefore implicated in the development of this disorder. Nerve tissues require glucose energy to function and survive. Upon excessive glucose entry into the peripheral nerve, the glycolytic pathway and collateral glucose-utilizing pathways are overactivated and initiate adverse effects on nerve tissues. During hyperglycemia, flux through the polyol pathway, formation of advanced glycation end-products, production of free radicals, flux into the glucosamine pathway, and protein kinase C activity are all enhanced to negatively influence nerve function and structure. Suppression of these aberrant metabolic pathways has succeeded in prevention and inhibition of the development of neuropathy in animal models with diabetes. Satisfactory results were not attained, however, in patients with diabetes and further clinical trials are required. In this review, the author summarizes the hitherto proposed theories on the pathogenesis of diabetic neuropathy related to glucose metabolism and future prospects for the effective treatment of neuropathy.

Phenotyping animal models of diabetic neuropathy: a consensus statement of the diabetic neuropathy study group of the EASD (Neurodiab)

NIDDK, JDRF, and the Diabetic Neuropathy Study Group of EASD sponsored a meeting to explore the current status of animal models of diabetic peripheral neuropathy. The goal of the workshop was to develop a set of consensus criteria for the phenotyping of rodent models of diabetic neuropathy. The discussion was divided into five areas: (1) status of commonly used rodent models of diabetes, (2) nerve structure, (3) electrophysiological assessments of nerve function, (4) behavioral assessments of nerve function, and (5) the role of biomarkers in disease phenotyping. Participants discussed the current understanding of each area, gold standards (if applicable) for assessments of function, improvements of existing techniques, and utility of known and exploratory biomarkers. The research opportunities in each area were outlined, providing a possible roadmap for future studies. The meeting concluded with a discussion on the merits and limitations of a unified approach to phenotyping rodent models of diabetic neuropathy and a consensus formed on the definition of the minimum criteria required for establishing the presence of the disease. A neuropathy phenotype in rodents was defined as the presence of statistically different values between diabetic and control animals in 2 of 3 assessments (nocifensive behavior, nerve conduction velocities, or nerve structure). The participants propose that this framework would allow different research groups to compare and share data, with an emphasis on data targeted toward the therapeutic efficacy of drug interventions.

Efficacy and safety of pregabalin for treating neuropathic pain associated with diabetic peripheral neuropathy: a 14 week, randomized, double-blind, placebo-controlled trial

AIMS

To evaluate the efficacy, safety and pharmacokinetics of pregabalin in treating neuropathic pain associated with diabetic peripheral neuropathy in Japanese patients.

METHODS

A randomized, double-blind, placebo-controlled, multicentre 14 week clinical trial was conducted. Japanese patients with diabetic peripheral neuropathy (n = 317) were randomized to receive placebo or pregabalin at 300 or 600 mg/day. The primary efficacy measure was a change of mean pain score from baseline to end-point from patients' daily pain diaries.

RESULTS

Significant reductions in pain were observed in patients treated with pregabalin at 300 and 600 mg/day vs. placebo (P < 0.05). Improvements in weekly pain scores were observed as early as week 1 and were sustained throughout the study period (300 and 600 mg/day difference from placebo at study end-point, -0.63 and -0.74, respectively). Pregabalin produced significant improvements in weekly sleep interference scores, the short-form McGill Pain Questionnaire, the Medical Outcomes Study-Sleep Scale, the 36-item Short-Form Health Survey scale, and the Patient and Clinical Global Impression of Change. Patient impressions of numbness, pain and paraesthesia were also significantly improved. Regarding treatment responders, 29.1 and 35.6% of patients treated with 300 and 600 mg/day, respectively, reported ≥ 50% improvement in mean pain scores (vs. 21.5% for placebo). Pregabalin was well tolerated; somnolence (26%), dizziness (24%), peripheral oedema (13%) and weight gain (11%) were the most common adverse events and generally were reported as mild to moderate.

CONCLUSIONS

Pregabalin was effective in reducing pain and improving sleep disturbances due to pain, and was well tolerated in Japanese patients with painful DPN.

Spindle cell metaplasia arising in thyroid adenoma: characterization of its pathology and differential diagnosis

Spindle cell metaplasia in thyroid adenoma or carcinoma is rare and its pathological features are not well characterized. Distinction of this entity from medullary or anaplastic carcinoma has an important clinical implication. We encountered a case of thyroid follicular adenoma associated with spindle cell metaplasia. It showed "tumor in tumor appearance" and neoplastic spindle cells were positive for thyroglobulin, thyroid transcription factor-1, vimentin and focally chromogranin A and somatostatin (SS). MIB-1 index was <1%. Ultrastructure of the spindle cells was reminiscent of follicular cell origin. From the findings from our case, spindle cell metaplasia appears to be a benign clinical entity, suggestive of multidirectional differentiation of follicular cells.

Ossifying gastric carcinoid tumor containing bone morphogenetic protein, osteopontin and osteonectin

We report a case of gastric carcinoid tumor with ossification. A 47-yr-old man complaining of abdominal discomfort underwent gastrointestinal endoscopic examination, which revealed a submucosal tumor in his stomach. The tumor was extirpated by endoscopic enucleation. Histologically, the tumor was widely occupied by mature bone tissues, where scattered carcinoid tumor cell nests surrounded bone tissues or located in stromal areas. Immunohistochemically, the tumor cells were strongly positive for cytokeratin, chromogranin A, synaptophysin, neurofilaments and neuron-specific enolase, underscoring the diagnosis of carcinoid tumor. They also stained positive with markers of bone formation and differentiation, such as bone morphogenetic protein, osteopontin and osteonectin. There are only four cases in the world literature, including a current case of ossifying gastric carcinoid tumor, in which the excessive production of peptides promoting ossification was considered to be implicated in the unusual appearance of the bone.

Chronic granulomatous pleuritis caused by nocardia: PCR based diagnosis by nocardial 16S rDNA in pathological specimens

Nocardiosis is an uncommon infection caused by the aerobic actinomycete nocardia. Identification of the pathogen is essential for the definitive diagnosis and for an effective treatment. This report describes a case of chronic granulomatous pleuritis caused by nocardia. A 59 year old Japanese man had a history of repeated pyothorax. Right pleural decortication and thoracic drainage were performed. Microbiological examinations of the drained fluid failed to identify a pathogen. Pathological examinations revealed Gram positive filamentous and branching bacilli in the granulomatous lesion of the pleura. Sequencing of the 971 bp 16S ribosomal DNA extracted and amplified from paraffin wax embedded sections identified the microorganism as Nocardia sp. IFM 0860. The patient received sulfamethoxazol/trimethoprim and minocycline. Although the presence of a brain abscess was disclosed by systemic examination, the clinical course has been favourable. In this patient, polymerase chain reaction analysis of 16S ribosomal DNA in pathological specimens was useful in making an accurate diagnosis of nocardiosis and in determining the appropriate treatment.

Diabetic microangiopathy: pathology and current understanding of its pathogenesis

Recent drastic increase in diabetic population poses serious problems in both health sciences and socioeconomic conditions. The most important issue in the clinical practice of diabetic patients is the treatment and care of chronic complications. It is not fully clear, however, as to the pathophysiology of diabetic microangiopathy and its pathogenesis. Recent studies on microvessel pathology in diabetic patients and molecular analyses on the diabetic animal models disclosed novel features of the dynamic changes of specific organ pathology affected by diabetes and factors involved in its pathogenesis. Under long-term hyperglycemia, early stimuli elicit adaptive reactions of tissues showing acute inflammatory processes of vessel walls and then late irreversible and regressive changes of microangiopathy. Consequently, remodeling of vascular cells and excessive matrix production are cardinal feature. The precise mechanisms of how these tissue changes occur remain speculative; increased polyol pathway, excessive non-enzymatic glycation, increased protein kinase C activity, as well as oxidative stress are all interrelated for the cause and development of the microangiopathy.

Reduced beta-cell mass and expression of oxidative stress-related DNA damage in the islet of Japanese Type II diabetic patients

AIMS/HYPOTHESIS

We examined the pancreatic islet lesions in Japanese patients with Type II diabetes mellitus to determine if the damage was related to oxidative stress.

METHODS

Morphometric analyses were performed on immunostained sections of the tail portion of the pancreas from 14 diabetic and 15 non-diabetic patients. Amyloid deposition and oxidative stress-induced tissue damage were evaluated by Congo-red staining and immunostaining. Resistance to oxidative stress was assessed from immunostaining results for Cu, Zn-superoxide dismutase (SOD). Expression of (pro)insulin mRNA was assessed by in situ hybridisation.

RESULTS

The pancreas from diabetic patients had amyloid deposition in about 15 % of the islets, intensified reactions of 8-OHdG and HNE, as well as reduced expression of SOD. Islet volume density of beta cells and total beta-cell mass in the pancreas from diabetic patients were reduced by 22 % (p < 0.001) and 30 % (p < 0.05). Islet volume density and total mass of (pro)insulin mRNA-positive cells were similarly reduced in diabetic patients by 22 % (p < 0.001) and 39 % (p < 0.05), respectively. Islet volume density of A cells was increased by 20 % (p < 0.001) but total mass did not change. There were no changes in volume densities of islet, D and PP cells. Reduced beta-cell volume density correlated with increased positive staining of 8-OHdG.

CONCLUSION/INTERPRETATION

Japanese Type II diabetic patients show a reduction of beta-cell mass and evidence of increased oxidative stress-related tissue damage that is correlated with the extent of the beta-cell lesions.

Reduced beta-cell mass and expression of oxidative stress-related DNA damage in the islet of Japanese Type II diabetic patients

AIMS/HYPOTHESIS

We examined the pancreatic islet lesions in Japanese patients with Type II diabetes mellitus to determine if the damage was related to oxidative stress.

METHODS

Morphometric analyses were performed on immunostained sections of the tail portion of the pancreas from 14 diabetic and 15 non-diabetic patients. Amyloid deposition and oxidative stress-induced tissue damage were evaluated by Congo-red staining and immunostaining. Resistance to oxidative stress was assessed from immunostaining results for Cu, Zn-superoxide dismutase (SOD). Expression of (pro)insulin mRNA was assessed by in situ hybridisation.

RESULTS

The pancreas from diabetic patients had amyloid deposition in about 15 % of the islets, intensified reactions of 8-OHdG and HNE, as well as reduced expression of SOD. Islet volume density of beta cells and total beta-cell mass in the pancreas from diabetic patients were reduced by 22 % (p < 0.001) and 30 % (p < 0.05). Islet volume density and total mass of (pro)insulin mRNA-positive cells were similarly reduced in diabetic patients by 22 % (p < 0.001) and 39 % (p < 0.05), respectively. Islet volume density of A cells was increased by 20 % (p < 0.001) but total mass did not change. There were no changes in volume densities of islet, D and PP cells. Reduced beta-cell volume density correlated with increased positive staining of 8-OHdG.

CONCLUSION/INTERPRETATION

Japanese Type II diabetic patients show a reduction of beta-cell mass and evidence of increased oxidative stress-related tissue damage that is correlated with the extent of the beta-cell lesions.

Intramyocardial delivery of basic fibroblast growth factor-impregnated gelatin hydrogel microspheres enhances collateral circulation to infarcted canine myocardium

The present study examined whether basic fibroblast growth factor (bFGF)-impregnated acidic gelatin hydrogel microspheres (AGHM) would enhance collateral development to the infarct area in dogs with coronary occlusion. Studies were conducted in 28 dogs with a 2-week occlusion of the proximal left anterior descending coronary artery (LAD). The dogs were divided into 3 groups according to treatment: Group A treated with bFGF-impregnated AGHM in the infarct area; Group B with free-form bFGF; Group C with AGHM alone. Coronary angiography (n=15; Group A, 7 dogs; Group B, 5 dogs; Group C, 3 dogs) and a regional myocardial blood flow study (n=13; Group A, 6 dogs; Group B, 4 dogs; Group C, 3 dogs) were repeated at a 2-week interval. Coronary angiography revealed that in Group A, antegrade flow in the LAD distal to the occlusion, which was assessed by Thrombolysis in Myocardial Infarction (TIMI) grade, was significantly increased after treatment. In contrast, in Groups B and C, the treatment did not change the flow grade in the LAD. In Group A, the regional myocardial blood flow in the collateral dependent area was significantly increased after treatment, and the regional myocardial blood flow reserve after adenosine injection was also significantly increased. These measurements remained after treatment in Groups B and C. The immunohistochemical study with factor VIII-related antigen revealed an increase of vascular density in the ischemic region in Group A. Intramyocardial delivery of bFGF-impregnated AGHM, but not free-form bFGF, improves the collateral circulation to the infarct area of a coronary occlusion in dogs.

Neuropathy in diabetic mice overexpressing human aldose reductase and effects of aldose reductase inhibitor

The present study was designed to examine the effect of aldose reductase (AR) overexpression on the development of diabetic neuropathy by using mice transgenic for human AR. At 8 weeks of age, transgenic mice (Tg) and non-transgenic littermates (Lm) were made diabetic with streptozotocin. After 8 weeks of untreated diabetes, plasma glucose levels and the reduction in body weight were similar between the groups of diabetic animals. Despite the comparable levels of hyperglycaemia, levels of sorbitol and fructose were significantly greater in the peripheral nerve of diabetic Tg than in diabetic Lm (both P < 0.01). Ouabain sensitive Na(+),K(+)-ATPase activity was similarly decreased in both diabetic Tg and Lm. Protein kinase C activity in the sciatic nerve membrane fraction was unaffected by diabetes in Lm, but was reduced by nearly 40% in the diabetic Tg. Although both groups of diabetic animals exhibited a significant decrease in tibial nerve motor nerve conduction velocity (MNCV), this decrease was significantly more severe (P < 0.01) in diabetic Tg than in diabetic Lm. Consistent with these findings, nerve fibre atrophy was significantly more severe in diabetic Tg than in diabetic Lm (P < 0.01). These findings implicate increased polyol pathway activity in the pathogenesis of diabetic neuropathy. In support of this hypothesis, treating diabetic Tg with an aldose reductase inhibitor (WAY121-509, 4 mg/kg/day) for 8 weeks significantly prevented the accumulation of sorbitol, the decrease in MNCV and the increased myelinated fibre atrophy in diabetic Tg.

[Epidemiologic study of diabetic retinopathy in nine hospitals in the Aomori area]

PURPOSE

To examine the prevalence of diabetic retinopathy and the relationship between diabetic retinopathy and systemic risk factors.

METHODS

A cross sectional study of diabetic retinopathy was conducted on 1,826 eyes of 913 randomly selected patients with type 2 diabetes in 9 central hospitals in Aomori Prefecture and the surrounding district. Retinopathy levels and maculopathy were assessed by binocular funduscopy, fundus photography and, if necessary, by fluorescein angiography. Multiple logistic regression analysis was performed to determine independent effects of systemic risk factors on diabetic retinopathy.

RESULTS

The prevalence of background retinopathy was 31%, of preproliferative retinopathy 5%, and of proliferative retinopathy 5% in all patients. However, in 3 hospitals in which the patients were routinely examined by fluorescein angiography, background retinopathy was found to be present in 60%, preproliferative retinopathy in 5%, and prolifertive retinopathy in 7%. Maculopathy was found in 8% of diabetic patients and the prevalence was 11% in the eyes with background retinopathy, 40% with preproliferative retinopathy, and 50% with proliferative retinopathy. Multiple logistic regression analysis showed that retinopathy was significantly associated with duration of diabetes, methods of diabetic control, hypertension, nephropathy, and neuropathy.

CONCLUSION

The detection rate of background diabetic retinopathy by fluorescein angiography was twice as sensitive as that by binocular funduscopy and fundus photography. The prevalence of maculopathy increases with the progression of retinopathy. Several systemic risk factors have significant association with diabetic retinopathy and maculopathy.

Granulomatous colitis associated with botryomycosis of Propionibacterium acnes

Propionibacterium acnes, an anaerobic, non-spore-forming, gram-positive bacillus, is a common inhabitant of the skin, and its virulence is considered to be low in humans. This report describes an unusual case of granulomatous colitis associated with P acnes infection in a 46-year-old woman. The affected cecum exhibited a tumor histologically characterized by massive transmural infiltrates of small lymphocytes and noncaseating epithelioid granulomas with multinucleated giant cells. Botryomycotic granules were also found in the muscular layer and paracolic connective tissues and consisted of gram-positive bacilli with filamentous growth. Polymerase chain reaction confirmed the presence of P acnes 16S ribosomal DNA in the surgical specimen of the colon. The patient developed a postoperative P acnes-induced peritonitis, which subsided with treatment with antibiotics and surgical drainage. The present case indicates that P acnes is one of the possible pathogens for granulomatous colitis.

Malignant glomus tumor in the branchial muscle of a 16-year-old girl

Malignant glomus tumor is an extremely rare neoplasm and its histological features are not well characterized. We report a 16-year-old female patient with a malignant glomus tumor. The patient was admitted to our hospital presenting with a mass in the right upper arm that she had noticed for the previous 6 months. Computed tomography and magnetic resonance imaging revealed an expanded mass involving the surrounding tissues. At surgery, an ill-defined and expanded mass was found, 5 x 4 x 3 cm in size, in the right branchial muscle. The tumor was extirpated, along with neighboring muscle tissues. Histologically, tumor cells were round to short-spindle shaped, forming solid sheets admixed with vessels of varying size. Their nuclei were uniformly oval to round, and their cytoplasms were slightly eosinophilic. The growth pattern of the tumor cells resembled that of glomus tumor, but mitotic figures were frequent (as high as 10 per 10 high-power fields). Immunohistochemically, the tumor cells were positive for vimentin and muscle actin, but negative for desmin. There were no areas typical of benign glomus tumor or sarcomatous change. These findings led us to a diagnosis of primary malignant glomus tumor arising de novo. There has been no recurrence or metastasis for 21 months after wide excision.

Enhanced in situ expression of aldose reductase in peripheral nerve and renal glomeruli in diabetic patients

To explore the relationships between polyol pathway-related enzymes and pathologic features, we examined the immunohistochemical expression of aldose reductase (AR) and sorbitol dehydrogenase (SDH) in the peripheral nerve and kidney tissues collected postmortem from diabetic patients and compared it with those from non-diabetic patients. Tissue AR protein concentrations were also quantified. In non-diabetic patients, AR distributed in pericytes, smooth muscle cells of endo- and epi-neurial microvessels, Schwann cells in the sciatic nerve, and tubular cells of the renal medulla. By contrast, positive SDH reactions were observed in tubular cells of the renal cortex but were faint in the sciatic nerve. Diabetic patients frequently showed dense AR expressions in the sciatic nerve. In nephropathic diabetic patients, the glomerular mesangial area showed diffuse positive reactions for AR. The severity of structural changes in glomeruli correlated with the intensity of immunoreactive AR (r2=0.626, P<0.01). AR contents in the renal cortex and sciatic nerve from diabetic patients were 1.5- and 1.8-fold greater than those from non-diabetic patients, respectively (P<0.05 for both). These findings are the first to demonstrate enhanced AR expressions in peripheral nerve and renal glomeruli in diabetic patients and its relevance to the characteristic pathology.

Effects of OPB-9195, anti-glycation agent, on experimental diabetic neuropathy

BACKGROUND

Nonenzymatic glycation of neural proteins and their end-products (advanced glycation end-products, AGE) have been implicated in the pathogenesis of diabetic neuropathy. We need a development of effective ant-glycation agents for future clinical use.

MATERIALS AND METHODS

We examined the effects of OPB-9195 (OPB), a new inhibitor of glycation, on the peripheral nerve structure and function in diabetic rats. Eight-week-old Wistar rats were made diabetic by streptozotocin (40 mg kg(-1), i.v.) and OPB (60 mg kg(-1) day(-1)) was given by gavage for 24 weeks. Age- and sex-matched normal Wistar rats were used for comparison.

RESULTS

During the experimental period, OPB treatment did not affect the reduced body weight, elevated levels of blood glucose and glycated haemoglobin in diabetic rats. At the end of the experiment, delayed tibial motor nerve conduction velocity was significantly improved (by 60%) in treated diabetic rats, with reduction of serum AGE levels. Expression of immunoreactive AGE in the sciatic nerve was reduced in treated diabetic rats compared with those in untreated rats. Sciatic nerve (Na+, K+)-ATPase activity was also restored in treated diabetic rats. On the cross-sectioned sciatic nerves, positive cells with oxidative stress-related DNA damage, as expressed by 8-hydroxy-2'-deoxyguanosine, were less in the peripheral nerve of treated diabetic rats compared with those of untreated rats.

CONCLUSION

The current study suggested that OPB is beneficial for the reduction of serum AGE and the prevention of diabetic neuropathy.

Primary chondrosarcoma arising in the parotid gland

We report an extremely rare case of chondrosarcoma arising in the left parotid gland in a 45-year-old man who complained of painless swelling of the postauricular region. Computed tomography revealed a well-circumscribed tumor in the parotid area with a rim of scattered calcification. Under the diagnosis of benign parotid tumor, the tumor mass was removed with adequate margin. Histologic features were consistent with a low-grade chondrosarcoma showing lobular growth but clearly separated from adjacent glandular tissue of the parotid gland. Entire examination of the tumor disclosed no component of pleomorphic adenoma. There has been no evidence of recurrence for 2 months after the operation. The current case indicates that the parotid gland could be the site of occurrence of de novo primary chondrosarcoma.

Effects of 15-month aldose reductase inhibition with fidarestat on the experimental diabetic neuropathy in rats

We examined the effects of long-term treatment with an aldose reductase inhibitor (ARI) fidarestat on functional, morphological and metabolic changes in the peripheral nerve of 15-month diabetic rats induced by streptozotocin (STZ). Slowed F-wave, motor nerve and sensory nerve conduction velocities were corrected dose-dependently in fidarestat-treated diabetic rats. Morphometric analysis of myelinated fibers demonstrated that frequencies of abnormal fibers such as paranodal demyelination and axonal degeneration were reduced to the extent of normal levels by fidarestat-treatment. Axonal atrophy, distorted axon circularity and reduction of myelin sheath thickness were also inhibited. These effects were associated with normalization of increased levels of sorbitol and fructose and decreased level of myo-inositol in the peripheral nerve by fidarestat. Thus, the results demonstrated that long-term treatment with fidarestat substantially inhibited the functional and structural progression of diabetic neuropathy with inhibition of increased polyol pathway flux in diabetic rats.

Apoptosis, bcl-2 expression and p53 accumulation in myelodysplastic syndrome, myelodysplastic-syndrome-derived acute myelogenous leukemia and de novo acute myelogenous leukemia

Apoptosis and its dysregulation have been implicated in dysplastic and ineffective hematopoiesis and the neoplastic transformation of bone marrow in myelodysplastic syndrome (MDS). To explore the role of apoptosis in hematological disorders, we examined the frequency of apoptotic cells by the in situ end labeling method in bone marrow specimens from 37 patients with MDS [refractory anemia (RA) 10 cases, RA with excess of blasts (RAEB) 27 cases including 12 cases with leukemic transformation], 12 patients with MDS-derived acute myelogenous leukemia (AML) and 13 patients with de novo AML. In addition, we investigated the relationship of apoptosis to the immunohistochemical expression of bcl-2 and p53 in these cases, and the association of apoptosis, bcl-2, and p53 with the leukemic evolution of MDS by examining sequential bone marrow samples of the same patient from the time of initial diagnosis to the time of overt leukemia. The percentage frequency of apoptotic cells was significantly greater in MDS (RA: 9.46 +/- 2.99%, m +/- SD; RAEB: 5. 60 +/- 3.09) as compared with those in MDS-derived AML (0.62 +/- 0. 37), de novo AML (0.28 +/- 0.11) and controls (1.00 +/- 0.59). On the other hand, the cases of RAEB with leukemic transformation exhibited a lower frequency of apoptotic cells and a higher frequency of bcl-2- and p53-positive cells than those without transformation. When the RAEB cases transformed to AML, the frequency of apoptotic cells was significantly reduced (2.96 +/- 1. 54 --> 0.62 +/- 0.37), while the frequencies of bcl-2-positive cells and p53-positive cells were greater (10.88 +/- 3.66 --> 30.54 +/- 7. 14, and 20.21 +/- 6.21 --> 32.34 +/- 14.71, respectively). In contrast to MDS-derived AML, over a half of de novo AML cases showed few p53-positive cells. These findings corroborate the earlier notion that apoptosis may play a substantial role in dysplastic and ineffective hematopoiesis in MDS. It is also suggested that the suppression of apoptosis associated with enhanced bcl-2 expression and p53 accumulation increases the probability of developing leukemia in MDS, and that oncogenetic development might be different between MDS-derived AML and de novo AML.

Inhibition of progressive reduction of islet beta-cell mass in spontaneously diabetic Goto-Kakizaki rats by alpha-glucosidase inhibitor

The Goto-Kakizaki (GK) rat, an animal model of type 2 diabetes, exhibits mild hyperglycemia with a reduction of beta-cell mass. The mechanism for islet structural changes in this model and whether the changes are affected by metabolic control are not known. In the present study, we examined the process of islet changes in male GK rats aged 6, 8, 12, 24, and 36 weeks. Treatment effects with an alpha-glucosidase inhibitor (Voglibose; Takeda, Osaka, Japan) for 24 weeks (12 to 36 weeks of age) were also evaluated. The beta-cell mass increased until 8 weeks of age in both GK and control rats, but the increase was significantly (P < .01) smaller in GK rats versus at 8 weeks of age. Thereafter, the beta-cell mass decreased in GK rats, whereas it remained constant in controls. Voglibose treatment significantly (P < .01) inhibited the reduction of beta-cell mass in GK rats. Proliferative activity of beta cells as measured by bromodeoxyuridine (BrdU) uptake was significantly (P < .05) lower in GK rats versus control rats at 6 and 8 weeks, but the difference disappeared after 12 weeks of age, regardless of Voglibose treatment. The present study thus demonstrates a progressive loss of beta cells in GK rats that was mitigated by Voglibose treatment. We consider that the beta-cell loss in GK rats was due to an early impairment in proliferative activity and reduced survival. Voglibose did not appear to stimulate beta-cell proliferation, but exerted its effect via a reduction of hyperglycemia.

Increased in situ expression of nitric oxide synthase in human colorectal cancer

There is growing evidence that nitric oxide (NO) has an important role in tumor growth. However, information on the expression of NO synthase (NOS) in colorectal cancers is scanty. We therefore investigated the distribution and expression of NOS in human colorectal cancers. The expression of three types of NOS, inducible (iNOS), endothelial (eNOS) and neuronal (nNOS), was examined by immunohistochemistry in 25 cases of colorectal cancer. The expression of iNOS was also investigated at the mRNA level using the reverse transcriptase polymerase chain reaction (RT-PCR) in 6 cases. Correlations were made between iNOS expression and the histopathological findings. Immunoreactive iNOS was detected in the tumor cells in 22 cases (88%) with diffuse cytoplasmic reactions. Expression of iNOS-mRNA detected by RT-PCR in three tumor tissues was over five-fold that in normal mucosa. Intensified immunoreactivity of iNOS was associated with vascular invasion. iNOS expression did not correlate with pathological staging, tumor size, lymph node metastasis, p53 expression or tumor vessel density. Immunoreactive eNOS stained more strongly in the endothelial cells of microvessels within and around the tumor than in the areas remote from the tumor. There is enhanced expression of iNOS and eNOS in human colorectal cancers, which may correlate with tumor growth and vascular invasion.

Effects of long-term treatment with alpha-glucosidase inhibitor on the peripheral nerve function and structure in Goto-Kakizaki rats: a genetic model for type 2 diabetes

BACKGROUND

Continuous hyperglycemia is implicated in the pathogenesis of chronic diabetic complications. It is not well known, however, how and to what extent the development of neuropathy is inhibited by blood glucose control in subjects with Type 2 diabetes. We investigated therefore the effects of an alpha-glucosidase inhibitor (voglibose; Vg) on neuropathic changes in diabetic Goto-Kakizaki (GK) rats, a genetic model for Type 2 diabetes.

METHODS

Twelve week-old male GK rats were given a diet containing Vg (50 ppm) for 24 weeks and monitored for blood glucose, glycated hemoglobin, motor nerve conduction velocity (MNCV). At the end of the administration period (Na(+), K(+))-ATPase activity and the structure of the peripheral nerves were examined. Age- and sex-matched normal Wistar rats were treated similarly and served as controls.

RESULTS

GK rats showed fasting hyperglycemia after 8 weeks of age, and Vg treatment significantly lowered levels of blood glucose and glycated hemoglobin. Slowing of MNCV to 80% of normal control levels was detected in GK rats. Vg treatment inhibited this delay by 24% at 24 weeks and 57% at 36 weeks of age. Nerve (Na(+), K(+))-ATPase activity was reduced to 80% of normal control levels in GK rats and was restored by Vg treatment. Teased fiber studies revealed a higher incidence of fibers with paranodal, segmental demyelination and axonal degeneration in GK rats. Vg treatment significantly inhibited the development of these nerve-fiber abnormalities.

CONCLUSIONS

Lowering of high blood glucose levels achieved by the use of Vg in GK rats improved MNCV and demyelinative nerve changes with restoration of (Na(+), K(+))-ATPase activity.

Expression of tumor necrosis factor-alpha and interleukin-6 in oral squamous cell carcinoma

To explore the role of cytokines in tumor development and clinical manifestations, we examined the expressions of tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) in tumor tissues obtained from 57 patients with oral squamous cell carcinoma (OSCC) and their relationships to pathological grade and staging. Enzyme-linked immunosorbent assay on the tumor tissues demonstrated elevated concentrations of TNF-alpha and IL-6 proteins and upregulated mRNA levels were detected by the reverse transcription-polymerase chain reaction method when compared to those in normal control tissues. These cytokines and their transcripts were localized in stromal macrophages and in the tumor cells in particular of the front area of tumor tissues, possibly indicating active synthesis of these cytokines by tumor cells. Larger-sized tumors (T3, 4) contained significantly greater levels of IL-6 proteins than small-sized tumors (T1, 2) (P<0.05). The levels of these cytokines were significantly reduced in cases with effective pre-treatment with radiation or anti-cancer agents compared to those in the less effective group (P<0.05, grade IIa vs. grade IV for both TNF-alpha and IL-6). The present study thus demonstrated enhanced expression of cytokines in OSCC tissues.

Rectal adenocarcinoid with lymph node metastasis

We describe a case of a rare variant of a rectal carcinoid tumor that showed mucous gland differentiation accompanied by a lymph node metastasis with a histological appearance similar to that of the primary site. The tumor consisted of a typical argyrophilic carcinoid component and of goblet cell glands. The carcinoid component was positive for neuron-specific enolase, chromogranin A and synaptophysin. The goblet cells stained positively with periodic acid-Schiff (PAS) and alcian blue, and expressed carcinoembryonic antigen, but were negative for neuroendocrine markers. This case suggests that carcinoid tumor can differentiate towards mucus glands, which can also be found in the metastatic site.

Only limited effects of aminoguanidine treatment on peripheral nerve function, (Na+,K+)-ATPase activity and thrombomodulin expression in streptozotocin-induced diabetic rats

AIMS/HYPOTHESIS

Aminoguanidine, a potent anti-glycation reagent, is known to be beneficial in experimental diabetic neuropathy. In this study, we explored the mechanisms of how aminoguanidine inhibits neuropathic changes in diabetes and compared its effects with those of insulin treatment.

METHODS

Wistar rats, aged 8 weeks, were made diabetic by streptozotocin and given aminoguanidine dissolved in drinking water (1 g/l) for 8 weeks. Effects of daily insulin (protamine-zinc) treatment were also examined for comparison. At the end of the 8 weeks, we examined the peripheral nerve function and (Na+,K+)-ATPase activity and their relation to serum thrombomodulin concentrations that are considered as a marker of endothelial injury.

RESULTS

Aminoguanidine treatment reduced the diabetes-induced decrease in tibial nerve conduction velocity by 47% (p < 0.05 vs untreated diabetic rats) and inhibited the loss of sciatic nerve (Na+,K+)-ATPase activity by 54% (p < 0.05 vs untreated diabetic rats). Insulin-treatment of diabetic rats restored these variables by 83% and 75%, respectively (both, p < 0.01 vs untreated diabetic rats). Thrombomodulin concentrations were increased (p < 0.01) in diabetic rats compared with those in non-diabetic controls and unaffected by aminoguanidine treatment. In contrast, the concentrations remained within the normal range in the insulin-treated group.

CONCLUSION/INTERPRETATION

Although aminoguanidine treatment improved nerve conduction velocity and (Na+,K+)-ATPase activity, its effects were considerably less than those of insulin and were not apparent in some measures of endothelial cell injury.

Peripheral nerve structure and function in long-term galactosemic dogs: morphometric and electron microscopic analyses

Experimental galactosemia for activating the polyol pathway is used extensively to explore the pathogenesis of diabetic complications. However, despite the presence of severe neuropathy in galactosemic rats, changes in the peripheral nerve have not been well established in galactosemic dogs. We therefore conducted biochemical, electrophysiological, and morphometric studies on peripheral nervous systems (PNS) in dogs given a 30% galactose diet for 44 months. Age- and sex-matched dogs given a 30% cellulose diet were used as control. Chronic galactosemia resulted in accumulation of galactitol and decrease in myo-inositol in the sciatic nerve. Electrophysiological and teased fiber analyses demonstrated no significant abnormalities in the ulnar and peroneal nerves in galactosemic dogs. Morphometric analyses revealed a tendency of myelinated fiber atrophy (24% reduction of average fiber size) associated with 20% decrease (P < 0.05 vs control) in mean myelinated fiber occupancy rate in the peroneal nerve in galactosemic dogs. In the anterior mesenteric ganglion, there was a slight but significant increase (8%) in mean neuronal cell size in galactosemic dogs (P < 0.05 vs control). Electron microscopy revealed that galactosemia did not produce dystrophic and degenerative changes in the autonomic ganglion in dogs. We conclude that structural and functional changes in the PNS of galactosemic dogs are mild and different from those of the rat model. These findings suggest that the severity of peripheral neuropathy induced by chronic galactosemia may be species dependent.

Accelerated loss of islet beta cells in sucrose-fed Goto-Kakizaki rats, a genetic model of non-insulin-dependent diabetes mellitus

The Goto-Kakizaki (GK) rat is a spontaneously diabetic animal model of non-insulin-dependent diabetes mellitus, which is characterized by progressive loss of beta cells in the pancreatic islets with fibrosis. In the present study, we examined the effects of sucrose feeding on the islet pathology in this model. Six-week-old GK rats were fed with 30% sucrose for 6 weeks to induce severe hyperglycemia, and their condition was compared with that of nontreated rats. Age-matched normal Wistar rats were also given sucrose for the same periods and used for comparison. The sucrose-treated GK rats showed elevated blood glucose levels on oral glucose tolerance tests at 60 minutes and 120 minutes, representing 123% and 127% of values in untreated GK rats, respectively. At the end of the study, the mean beta-cell volume density in GK rats was 50% less than that in untreated Wistar rats. Sucrose feeding further reduced the volume densities of beta cells to only 50% of the levels of age-matched GK rats. Apoptotic cells were found in islet beta cells only in GK rats fed sucrose (mean 0.067%). There appeared to be more islets that immunohistochemically stained strongly positive with 8-hydroxy-deoxyguanosine as a marker of oxidative damage of DNA in GK rats fed sucrose compared with those not given sucrose. GK rats not fed sucrose showed significantly lower proliferative activity of beta cells measured by 5-bromo-2'-deoxyuridine uptake and intensified expression of Bcl-2 immunoreactivities at 6 weeks of age compared with those in age-matched Wistar rats. These two indices were reduced in both GK and Wistar rats with increasing age and were not affected by sucrose feeding in either group. The present study thus indicated that sucrose feeding promoted the apoptosis of beta cells in GK rats through increased oxidative stress without altering their proliferative activity.

Rerupture of coil-embolized aneurysm during long-term observation. Case report

The authors describe the histopathological findings in a case involving rerupture of a recanalized aneurysm of the internal carotid artery 8 months after partial (95%) embolization with interlocking detachable coils. The aneurysm was filled with poorly organized thrombus, and its orifice was devoid of endothelial cells. It appears likely that a long period of observation may be required to confirm the complete thrombotic organization of coil-embolized aneurysms. This indicates that caution is needed because rupture may follow recanalization of the aneurysm.

Localization in human diabetic peripheral nerve of N(epsilon)-carboxymethyllysine-protein adducts, an advanced glycation endproduct

The present study was designed to elucidate in situ distribution of advanced glycation endproducts (AGE) in human peripheral nerve and whether the reaction products were excessive in the diabetic condition. For the detection of AGE, immunoperoxidase staining was undertaken on peripheral nerve samples obtained from 5 non-insulin-dependent diabetic patients and 5 non-diabetic control subjects. The anti-AGE antibody used in this study contained an epitope against N(epsilon)-carboxymethyllysine. Light microscopically, AGE localized in the perineurium, endothelial cells and pericytes of endoneurial microvessels as well as myelinated and unmyelinated fibers. At the submicroscopic level, AGE deposition appeared focally as irregular aggregates in the cytoplasm of endothelial cells, pericytes, axoplasm and Schwann cells of both myelinated and unmyelinated fibers. Interstitial collagens, basement membranes of the perineurium also reacted with this antibody. The AGE depositions were detected in both control and diabetic nerves, but were more intense in the latter. The excessive AGE deposition correlated with a reduction in myelinated fiber density. However, the localization of AGE was not directly associated with degeneration of nerve fibers and the link between AGE deposition and nerve fiber degeneration is yet to be determined. The present study thus demonstrated the excessive deposition of intra- and extracellular AGE in human diabetic peripheral nerve and strengthened the contention that the enhanced glycation may play a role in the development of diabetic neuropathy.

Immunohistochemical assessment of proliferative activity in mammary adenomyoepithelioma

AIMS

Two cases of adenomyoepithelioma of the breast were examined by immunohistochemistry to evaluate proliferative activity of epithelial and myoepithelial components.

METHODS AND RESULTS

The tumours showed a bicellular pattern of gland-forming epithelial cells and proliferative myoepithelial cells with clear cytoplasm. They showed foci of monotonous growth of myoepithelial cells devoid of glands with low mitotic rate (1-2/10 high-power fields) and mild cytological atypia. Immunohistochemically, the glandular cells were positive for epithelial membrane antigen, cytokeratin (KL-1 and CAM5.2) and carcinoembryonic antigen, whereas tumour cells with clear cytoplasm were reactive with muscle-specific actin (MSA), alpha smooth muscle actin, vimentin, and S100 protein but negative for desmin. Proliferative activities assessed by MIB-1 (Ki-67)/MSA positive cell index were greater in myoepithelial cells in both cases (19.2% and 17.7%) as compared to those in epithelial cells (MIB-1/CAM5.2 index: 10.2% and 9.5%).

CONCLUSIONS

These results might account for the previous findings that myoepithelial components predominate over the epithelial ones in an advanced stage of this tumour as well as in recurrent or metastatic lesions.

Effects of cilostazol on the peripheral nerve function and structure in STZ-induced diabetic rats

We examined the effect of cilostazol (CZ), antiplatelet agent and potent vasoactive compound, which has an inhibitory effect on tissue phosphodiesterase, on peripheral nerve in streptozotocin-induced diabetic rats. Diabetic rats were fed for 12 weeks with a chow containing 0.01% or 0.03% CZ (w/w) and the results were compared with untreated diabetic rats. The 0.03% CZ treatment significantly improved motor nerve-conduction velocity and restored nerve Na+, K(+)-ATPase activity in diabetic rats without affecting body weight and glycated hemoglobin levels, but the effects of 0.01% CZ treatment did not reach statistical difference. Elevated sorbitol and reduced myo-inositol levels in diabetic nerve tissues were not influenced by CZ treatment. Structural analysis of the sural nerve demonstrated a partial but significant effect on decreased mean myelinated fiber area and atrophic changes of the axon in diabetic rats treated with 0.01% CZ. CZ treatment inhibited reduction of pericyte area of endoneurial microvessels in diabetic rats. Expansion of endoneurial microvessels and luminal area in relation to vascular area also tended to be inhibited by CZ treatment. Thus CZ treatment ameliorated, although not completely, functional and structural abnormalities in peripheral nerve of diabetic rats without effecting the polyol pathway. These results support the contention that vascular factors may play an important role in the etiology of experimental diabetic neuropathy and suggest that CZ may have a beneficial therapeutic effect on diabetic neuropathy.

c-myc, c-erbB-1 and c-erbB-2 expressions in urothelial carcinoma

The expression of c-myc, c-erbB-1 and c-erbB-2 in 24 cases of urothelial carcinoma by Southern and northern blot analysis, and immunohistochemistry was examined. The results were compared with the pathological grade and stage. We found elevated mRNA expressions of c-myc and c-erbB-1 in 19 and 11 of 21 cases, respectively, but there was no apparent amplification or rearrangement of these oncogenes in any of the cases examined. By immunohistochemistry using anti-epidermal growth factor receptor antibody, most of the cases showed positive immunoreactivity on the cancer cell membranes, and cancers of higher pathological grade and stage showed more intense staining. By contrast, amplification of c-erbB-2 was detected in four of 24 cases, all of which were assigned to a high pathological grade (G3). Elevated c-erbB-2 mRNA levels appeared to correlate with the pathological grade of the cancers. Positive immunohistochemical reactions to c-erbB-2 were found in the cancer cell membranes in three of 24 cases, which were accompanied by amplification and elevated mRNA levels of c-erbB-2. In conclusion, expressions of c-myc, c-erbB-1 and c-erbB-2 were all elevated in the majority of urothelial carcinomas, but the amplification was not universal.

Effects of aminoguanidine on structural alterations of microvessels in peripheral nerve of streptozotocin diabetic rats

This study was designed to explore the effect of aminoguanidine (AG) on the structural abnormalities of microvessels in the sural nerve of streptozotocin-induced diabetic rats. Diabetic rats were treated with AG (25 mg/ kg, sc) for 16 weeks, a dose high enough to prevent glycation but also inhibit inducible nitric oxide synthase. Non-treated diabetic rats and normal Wistar rats were used for comparison. Morphometric analysis disclosed an expansion of vascular and luminal areas of endoneurial microvessels in diabetic rats, particularly of large size, compared to control rats. These changes were partially but significantly corrected by AG treatment. There was no closure of microvessels in diabetic rats. The mean ratio of basement membrane area to vascular area was significantly smaller in diabetic rats than that in normal control rats and basement membrane was not thickened in diabetic rats. The mean ratio of endothelial cell area to vascular area was smaller in diabetic rats than that in nondiabetic control rats, and it was not influenced by AG treatment. Numbers of microvessels per unit endoneurial area in diabetic rats were not different from those of control rats. These findings in conjunction with previous reports suggest that alterations of nerve blood flow detected in diabetic peripheral nerve may be relevant to structural alterations of endoneurial microvessels, which may be an early sign of endoneurial microangiopathy. We also consider that AG treatment is beneficial for experimental diabetic neuropathy, partially through the correction of endoneurial microcirculation.

Crystalloid formation in gastrointestinal schwannoma

We found intracytoplasmic crystalloids in two of six cases (33.3%) of gastrointestinal (GI) schwannomas. The crystalloid inclusions were periodic acid-Schiff (PAS) positive with diastase-resistance and stained blue with Masson's trichrome. They were needle-shaped and about 1 to 15 microm in length at microscopic levels. They had varying electron density revealed by electron microscopy and some of them showed distinct lattice structure with periodicity of about 9 nm. Survey of soft tissue schwannomas (n = 20) and S-100-negative GI stromal tumors (n = 41) did not detect such crystalloids. Although the origin and differentiation of GI stromal tumors (GISTs) have been a source of controversy, these intracytoplasmic crystalloids may be a marker for Schwann cell differentiation in some GIST.

P53 protein expression in pancreatic tumors and its relationship to clinicopathological factors and prognosis

We examined the expression of p53 protein by immunohistochemical method in a series of pancreatic tumors and evaluated its relationships to the clinicopathological factors and prognosis. The study involved 108 cases of pancreatic tumors (79 ductal carcinomas, 1 acinar cell carcinoma, 14 endocrine tumors, 6 solid cystic tumors, 8 benign ductal tumors) and 8 chronic pancreatitides. Thirty-nine cases of pancreatic ductal carcinoma (49.4%) were positive for p53 protein. Analysis of the Cox hazards model identified p53 positivity and stage at the initial operation as an independent prognostic factor. Patients with p53 positive ductal carcinomas had a greater risk of death compared to p53 negative cases (P < 0.05). There was, however, no statistically significant correlation between p53 protein expression and other clinicopathological factors. Cases of stage III and IVb with positive p53 showed a bleak prognosis compared to p53 negative cases (P < 0.05). Our results suggest that p53 expression is common in invasive pancreatic ductal carcinomas and may have a prognostic value.

Expression of nitric oxide synthase in macula densa in streptozotocin diabetic rats

Renal haemodynamic changes are suggested to be an early sign of diabetic glomerulopathy. The juxtaglomerular apparatus relevant to the renin angiotensin system, known to be the site of nitric oxide (NO) production, is considered to play a role in the regulation of glomerular blood flow. This study was therefore designed to clarify whether in situ expression of nitric oxide synthase (NOS) is altered in the kidney of diabetic rats. Streptozotocin-induced diabetic rats with 6, 8, 12 and 32 weeks diabetes duration and age-matched normal control rats were used. The expression of a constitutive form of NOS (cNOS, neural type) and NADPH diaphorase activity in the renal cortex were studied immunohistochemically and histochemically. Diabetic rats had lower body weight and heavier kidney mass compared to control rats at each time point examined. Mean glomerular surface area was greater in 6, 8 and 12-week diabetic rats compared to age-matched control rats. cNOS reaction was localized in the macula densa and appeared less intense in diabetic rats compared to age-matched control rats. The mean number of macula densa cells positive for cNOS in each glomerulus and in each glomerular area was significantly lower in diabetic rats compared to control rats at any time examined. In contrast, NADPH diaphorase activity was detected in both juxtaglomerular arterioles and macula densa cells. The staining reaction of NADPH diaphorase in the arterioles remained positive but appeared less intense in macula densa cells in diabetic rats. These results suggest that NO production in macula densa cells may be reduced in diabetic rats, modulating the vasodilatory function of afferent arterioles. Further investigation on the changes in inducible NOS as well as endothelial cNOS are necessary to clarify mechanisms of haemodynamic changes in the diabetic kidney.

Peripheral nerve pathology in rats with streptozotocin-induced insulinoma

Peripheral nerve structure was systematically examined in rats with insulinoma induced by streptozotocin (STZ). Normal Wistar rats, aged 3 months (n = 10), were treated with intravenous injections of STZ (20 mg/kg) and housed in plastic cages with free access to water and chow until 24 months of age. Three rats with insulinoma survived and were examined pathologically. Age-matched normal Wistar rats (n = 6) were used for comparison. The insulinoma-bearing rats showed a marked increase in body weight and decrease in blood glucose. In a teased nerve fiber study of the sciatic nerve, the percentage of abnormal fibers undergoing axonal degeneration and de- and remyelination in age-matched normal control rats was 3.9 +/- 2.5% (means +/- SD), whereas in the three insulinoma-bearing rats 49%, 50%, and 24%, respectively, of the fibers showed such changes. Regenerating fibers were also numerous in each insulinoma-bearing rat (36%, 42% and 27%, respectively). Morphometric analysis revealed smaller mean myelinated fiber and axonal areas in all the nerves examined (sciatic, tibial and sural) in insulinoma-bearing rats as compared to those in age-matched normal rats. Fiber area frequency histograms showed a decrease in large myelinated fibers and an increase in small regenerated fibers in insulinoma-bearing rats. Ultrastructurally, endoneurial microvessels exhibited a narrowed vascular lumen with swollen endothelial cells and vacuolar degeneration of pericytes, suggesting an involvement of vascular changes in the neuropathic development. The present study demonstrated marked structural changes in both motor and sensory peripheral nerves of rats bearing experimentally induced insulinoma. We consider that axonal degeneration, regeneration and demyelination constitute the main pathology in the peripheral nerves of insulinoma-bearing rats, although no particular difference in severity of the lesions between sensory and motor and between proximal and distal nerves was apparent.

Inhibition of development of peripheral neuropathy in streptozotocin-induced diabetic rats with N-acetylcysteine

N-acetylcysteine (NAC) is a precursor of glutathione (GSH) synthesis, a free radical scavenger and an inhibitor of tumour necrosis factor alpha (TNF). Because these functions might be beneficial in diabetic complications, in this study we examined whether NAC inhibits peripheral neuropathy. Motor nerve conduction velocity (MNCV) was significantly decreased in streptozotocin-induced-diabetic Wistar rats compared to control rats. Oral administration of NAC reduced the decline of MNCV in diabetic rats. Structural analysis of the sural nerve disclosed significant reduction of fibres undergoing myelin wrinkling and inhibition of myelinated fibre atrophy in NAC-treated diabetic rats. NAC treatment had no effect on blood glucose levels or on the nerve glucose, sorbitol and cAMP contents, whereas it corrected the decreased GSH levels in erythrocytes, the increased lipid peroxide levels in plasma and the increased lipopolysaccharide-induced TNF activity in sera of diabetic rats. Thus, NAC inhibited the development of functional and structural abnormalities of the peripheral nerve in streptozotocin-induced diabetic rats.

Galactosemic neuropathy in transgenic mice for human aldose reductase

We studied the functional consequences of an enhanced polyol pathway activity, elicited with galactose feeding, on the peripheral nerve of transgenic mice expressing human aldose reductase. Nontransgenic littermate mice were used as controls. With a quantitative immunoassay, the expression level of human aldose reductase in the sciatic nerve was 791 +/- 44 ng/mg protein (mean +/- SE), about 25% of that in human sural nerve. When the transgenic mice were fed food containing 30% galactose, significant levels of galactitol accumulated in the sciatic nerve. Galactose feeding of nontransgenic littermate mice led to a 10-fold lower accumulation of galactitol. Galactose feeding for 16 weeks caused a significant and progressive decrease in motor nerve conduction velocity in transgenic mice to 80% of the level of galactose-fed littermate mice, which was not significantly different from that of galactose-free littermate mice. A morphometric analysis of sciatic nerve detected > 10% reduction of mean myelinated fiber size but no alterations of myelinated fiber density in galactose-fed transgenic mice compared with other groups. The functional and structural changes that develop in galactose-fed transgenic mice are similar to those previously reported in diabetic animals. The results of these studies suggest that transgenic mice expressing human aldose reductase may be a useful model not only for defining the role of the polyol pathway in diabetic neuropathy but also for identifying and characterizing effective inhibitors specific for human aldose reductase.