Parents' Perception of Fissure Sealant Therapy in 6-12 Year Old Children: Evaluating a theory-driven intervention

BACKGROUND

Dental caries is considered a major global health issue and among the most challenging diseases worldwide. An effective way of preventing dental caries is the fissure sealant (FS) therapy.

OBJECTIVE

To determine the effectiveness of an educational intervention developed based on the health belief model (HBM) for parents' perception of FS therapy for their children.

METHODS

Quasi-experiment among 300 parents of 6-12 year-old children, 150 in the intervention group (IG) and 150 in the control (CG), in the south of Iran recruited via both clustering and convenience sampling. Data were collected using a validated questionnaire collecting demographic information, knowledge and data on HBM constructs and FS behaviour. Eight intervention sessions, 40-60 minutes long, were held for over month. The primary outcome was child's receipt of fissure sealants 3 months after the intervention.

RESULTS

The two groups had similar knowledge and the HBM constructs at baseline. After the intervention, the receipt of FS therapy was 65% and 12% in the IG and CG, respectively (p ⟨ 0.001, Chi Sq.). ANCOVA supported post-test differences between the intervention and control groups when accounting for baseline scores (p⟨0.05).

CONCLUSIONS

The educational HBM-based intervention improved parents' perceptions and their children's receipt of FS therapy. The intervention affected the HBM constructs. Barriers to healthy oral/dental behaviours may be reduced by interventions at multiple layers (beyond the individual level).

COVID-19: A systematic review and update on prevention, diagnosis, and treatment

Since the rapid onset of the COVID-19 or SARS-CoV-2 pandemic in the world in 2019, extensive studies have been conducted to unveil the behavior and emission pattern of the virus in order to determine the best ways to diagnosis of virus and thereof formulate effective drugs or vaccines to combat the disease. The emergence of novel diagnostic and therapeutic techniques considering the multiplicity of reports from one side and contradictions in assessments from the other side necessitates instantaneous updates on the progress of clinical investigations. There is also growing public anxiety from time to time mutation of COVID-19, as reflected in considerable mortality and transmission, respectively, from delta and Omicron variants. We comprehensively review and summarize different aspects of prevention, diagnosis, and treatment of COVID-19. First, biological characteristics of COVID-19 were explained from diagnosis standpoint. Thereafter, the preclinical animal models of COVID-19 were discussed to frame the symptoms and clinical effects of COVID-19 from patient to patient with treatment strategies and in-silico/computational biology. Finally, the opportunities and challenges of nanoscience/nanotechnology in identification, diagnosis, and treatment of COVID-19 were discussed. This review covers almost all SARS-CoV-2-related topics extensively to deepen the understanding of the latest achievements (last updated on January 11, 2022).

Cardiac risk stratification in emergency resection for colonic tumours

Background

Despite advances in perioperative care, the postoperative mortality rate after emergency oncological colonic resection remains high. Risk stratification may allow targeted perioperative optimization and cardiac risk stratification. This study aimed to test the hypothesis that the Revised Cardiac Risk Index (RCRI), a user-friendly tool, could identify patients who would benefit most from perioperative cardiac risk mitigation.

Methods

Patients who underwent emergency resection for colonic cancer from 2007 to 2017 and registered in the Swedish Colorectal Cancer Registry (SCRCR) were analysed retrospectively. These patients were cross-referenced by social security number to the Swedish National Board of Health and Welfare data set, a government registry of mortality, and co-morbidity data. RCRI scores were calculated for each patient and correlated with 90-day postoperative mortality risk, using Poisson regression with robust error of variance.

Results

Some 5703 patients met the study inclusion criteria. A linear increase in crude 90-day postoperative mortality was detected with increasing RCRI score (37.3 versus 11.3 per cent for RCRI 4 or more versus RCRI 1; P < 0.001). The adjusted 90-day all-cause mortality risk was also significantly increased (RCRI 4 or more versus RCRI 1: adjusted incidence rate ratio 2.07, 95 per cent c.i. 1.49 to 2.89; P < 0.001).

Conclusion

This study documented an association between increasing cardiac risk and 90-day postoperative mortality. Those undergoing emergency colorectal surgery for cancer with a raised RCRI score should be considered high-risk patients who would most likely benefit from enhanced postoperative monitoring and critical care expertise.

Self-reported and actual adherence to the Tokyo guidelines in the European snapshot audit of complicated calculous biliary disease

BACKGROUND

Complicated acute biliary calculous disease poses clinical challenges. The European Society of Trauma and Emergency Surgery (ESTES) snapshot audit of complicated biliary calculous disease aims to make novel comparisons between self-reported institutional adherence to the Tokyo guidelines (TG18) and 'real-world' contemporary practice across Europe.

METHODS

A preplanned analysis of a prospective observational multicentre audit that captured patients undergoing emergency admission for complicated biliary calculous disease (complicated cholecystitis, biliary pancreatitis, or choledocholithiasis with or without cholangitis) between 1 and 31 October 2018 was performed. An anonymized survey was administered to participating sites.

RESULTS

Following an open call for participation, 25 centres from nine countries enrolled 338 patients. All centres completed the anonymized survey. Fifteen centres (60 per cent) self-reported that a minority of patients were treated surgically on index admission, favouring interval cholecystectomy. This was replicated in the snapshot audit, in which 152 of 338 patients (45·0 per cent) underwent index admission cholecystectomy, 17 (5·0 per cent) had interval cholecystectomy, and the remaining 169 (50·0 per cent) had not undergone surgery by the end of the 60-day follow-up. Centres that employed a dedicated acute care surgery model of care were more likely to perform index admission cholecystectomy compared with a traditional general surgery 'on call' service (57 versus 38 per cent respectively; odds ratio 2·14 (95 per cent c.i. 1·37 to 3·35), P < 0·001). Six centres (24 per cent) self-reported routinely performing blood cultures in acute cholecystitis; patient-level audit data revealed that blood cultures were done in 47 of 154 patients (30·5 per cent). No centre self-reported omitting antibiotics in the management of acute cholecystitis, and 144 of 154 (93·5 per cent) of patients in the snapshot audit received antibiotics during their index admission.

CONCLUSION

Awareness of TG18 recommendations was high, but self-reported adherence and objective snapshot audit data showed low compliance with TG18 in patients with complicated acute biliary calculous disease.

Beta-blocker Therapy is Associated with Decreased 1-year Mortality After Emergency Laparotomy in Geriatric Patients

Background and Aims:

Emergency laparotomy is associated with a great risk of mortality in the elderly. The hyperadrenergic state induced by surgical trauma may play an important role in the pathophysiology of this increased risk. Studies have shown that beta-blocker exposure may be associated with decreased morbidity and mortality in the perioperative period. We aimed to study the effect of beta-blocker on mortality in geriatric patients undergoing emergency laparotomy.

Material and Methods:

This is a retrospective study of patients who underwent emergency laparotomy between 1 January 2015 and 31 December 2016 at a single institution. The outcomes of interest were the association between post-operative complications and in-hospital and 1-year mortality in patients on beta-blocker therapy (BB(+)) and those who were not (BB(−)). The Poisson regression analysis was used to evaluate the association.

Results:

A total of 192 patients were included of whom 62 (32.2%) had pre-operative beta-blocker therapy with continued exposure during their hospital stay. The in-hospital mortality was 17.7% in the BB(+) and 23.8% in the BB(−) cohorts ( p = 0.441). One-year mortality was significantly lower in the BB(+) group compared to the BB(−) group (30.6% versus 47.7%; p = 0.038). After adjusting for confounders, the incidence of deaths during 1 year post-operatively decreased by 35% in the BB(+) group (incidence rate ratio = 0.65, p = 0.004). No significant differences in the incidence of post-operative complications between the two groups could be measured.

Conclusion:

Beta-blocker therapy may be associated with reduced 1-year mortality following emergency laparotomy in geriatric patients.

Effect of beta-blocker therapy on early mortality after emergency colonic cancer surgery

Background

Emergency colorectal cancer surgery is associated with significant mortality. Induced adrenergic hyperactivity is thought to be an important contributor. Downregulating the effects of circulating catecholamines may reduce the risk of adverse outcomes. This study assessed whether regular preoperative beta-blockade reduced mortality after emergency colonic cancer surgery.

Methods

This cohort study used the prospectively collected Swedish Colorectal Cancer Registry to recruit all adult patients requiring emergency colonic cancer surgery between 2011 and 2016. Patients were subdivided into those receiving regular beta-blocker therapy before surgery and those who were not (control). Demographics and clinical outcomes were compared. Risk factors for 30-day mortality were evaluated using Poisson regression analysis.

Results

A total of 3187 patients were included, of whom 685 (21·5 per cent) used regular beta-blocker therapy before surgery. The overall 30-day mortality rate was significantly reduced in the beta-blocker group compared with controls: 3·1 (95 per cent c.i. 1·9 to 4·7) versus 8·6 (7·6 to 9·8) per cent respectively (P &lt; 0·001). Beta-blocker therapy was the only modifiable protective factor identified in multivariable analysis of 30-day all-cause mortality (incidence rate ratio 0·31, 95 per cent c.i. 0·20 to 0·47; P &lt; 0·001) and was associated with a significant reduction in death of cardiovascular, respiratory, sepsis and multiple organ failure origin.

Conclusion

Preoperative beta-blocker therapy may be associated with a reduction in 30-day mortality following emergency colonic cancer surgery.

β-Blocker after severe traumatic brain injury is associated with better long-term functional outcome: a matched case control study

PURPOSE

Severe traumatic brain injury (TBI) is the predominant cause of death and disability following trauma. Several studies have observed improved survival in TBI patients exposed to β-blockers, however, the effect on functional outcome is poorly documented.

METHODS

Adult patients with severe TBI (head AIS ≥ 3) were identified from a prospectively collected TBI database over a 5-year period. Patients with neurosurgical ICU length of stay <48 h and those dying within 48 h of admission were excluded. Patients exposed to β-blockers ≤ 48 h after admission and who continued with treatment until discharge constituted β-blocked cases and were matched to non β-blocked controls using propensity score matching. The outcome of interest was Glasgow Outcome Scores (GOS), as a measure of functional outcome up to 12 months after injury. GOS ≤ 3 was considered a poor outcome. Bivariate analysis was deployed to determine differences between groups. Odds ratio and 95% CI were used to assess the effect of β-blockers on GOS.

RESULTS

362 patients met the inclusion criteria with 21% receiving β-blockers during admission. After propensity matching, 76 matched pairs were available for analysis. There were no statistical differences in any variables included in the analysis. Mean hospital length of stay was shorter in the β-blocked cases (18.0 vs. 26.8 days, p < 0.01). The risk of poor long-term functional outcome was more than doubled in non-β-blocked controls (OR 2.44, 95% CI 1.01-6.03, p = 0.03).

CONCLUSION

Exposure to β-blockers in patients with severe TBI appears to improve functional outcome. Further prospective randomized trials are warranted.

Consistent high prevalence of Exophiala dermatitidis, a neurotropic opportunist, on railway sleepers

Environmental isolation of black yeasts potentially causing human disorders is essential for understanding ecology and routes of infection. Several Exophiala species show prevalence for man-made environments rich in monoaromatic compounds, such as creosote-treated or petroleum-stained railway sleepers. Ambient climatic conditions play a role in species composition in suitable habitats. Therefore, the aim of the present study was to establish the composition of Exophiala species in railway stations as a potential source of human infections in a subtropical region with evaluation of their antifungal susceptibility profiles. We examined 150 railway samples using cotton swabs moistened with sterile physiological saline. Black yeasts and relatives were selected on theirs colony morphology and identified based on ITS rDNA sequencing. Overall, 36 (24%) of samples were positive for black yeast-like fungi, i.e., Exophiala dermatitidis (n=20, 55.6%) was predominant, followed by E. phaeomuriformis (n=9, 25%), E. heteromorpha (n=5, 13.9%), and E. xenobiotica (n=2, 5.6%). Massive contaminations of E. dermatitidis were seen on railway sleepers on creosoted oak wood at the region close to the sea level, while in cold climates were primarily contaminated with clinically insignificant or rare human opportunists (E. crusticola). It seems that, high temperature and humidity are significant effect on species diversity. Moreover, the MIC results for all E. dermatitidis and E. phaeomuriformis strains revealed the widest range and the highest MICs to caspofungin (range 1-16mg/L, Geometric mean 4.912mg/L), and the lowest MIC for posaconazole (0.016-0.031mg/L, G mean 0.061mg/L). However, their clinical effectiveness in the treatment of Exophiala infections remains to be determined.

Is human Dectin-1 Y238X gene polymorphism related to susceptibility to recurrent vulvovaginal candidiasis?

Background and Purpose:

Vulvovaginal candidiasis is a frequent disease affecting approximately more than %75 of all childbearing women at least once in their lifetime by overgrowth of opportunistic Candida species. Recurrent vulvovaginal candidiasis (RVVC) is common in otherwise healthy individuals. Several risk factors were reported to contribute to RVVC susceptibility. A polymorphism in Dectin-1 (Y238X, rs16910526 ) was identified in patients with RVVC and hypothesized that genetic factors play an important role in susceptibility to RVVC. Herein, we aimed to survey the polymorphisms in the Dectin-1 gene, linked to susceptibility to RVVC.

Materials and Methods:

In the current study, blood samples were obtained from 25 patients who had frequent vulvovaginal candidiasis relapses and were diagnosed as RVVC. In addition, blood cultures were obtained from control group comprising of healthy individuals (n=25) with no history of RVVC, vaginal discharge, or itching on the day of examination. Dectin-1 Y238X gene polymorphism was investigated using Bi-PASA and DNA sequencing.

Results:

The analysis revealed that all of the patients were wild-type homozygous for Dectin-1 Y238X polymorphisms. None of the individuals showed heterozygous or mutant homozygous Dectin-1 polymorphism.

Conclusion:

No significant correlations were observed between the susceptibility to RVVC and Dectin-1 Y238X polymorphism in the Iranian population, which was not previously studied.

Development of a label-free SPR sensor for detection of matrixmetalloproteinase-9 by antibody immobilization on carboxymethyldextran chip

Surface plasmon resonance (SPR) immunosensor has been widely utilized for monitoring antigen-antibody interactions. The sensor measures changes of refractive index upon binding of analyte molecules to specific ligand immobilized on the sensor chip. This effort reports development of SPR immunosensor for real-time and label-free detection of recombinant human matrix metalloproteinases-9 (MMP-9), which has been associated with malignant tumor progression and metastasis by matrix degradation. MMP-9 was expressed in Escherichia coli BL21 and purified by Ni-NTA agarose column. CMD 50 D was activated by EDC/NHS for immobilization of monoclonal anti-MMP-9. Atomic force microscopy images showed uniform distribution of anti-MMP-9 over the sensor chip. Equilibrium constant (KD), maximum binding capacity (Rmax) and ∆Gb values for interaction of MMP-9 and anti-MMP-9 were 0.4nM, 680 µRIU and -53.51kJ/mol, respectively. Concentration of MMP-9 in saliva samples was determined, with linearity in the range of 10-200ng/mL. The limit of detection was found to be 8pg/mL, being lower than most of the previously reported techniques.

GIS based analysis of Intercity Fatal Road Traffic Accidents in Iran

Road traffic accidents including intercity car traffic accidents (ICTAs) are among the most important causes of morbidity and mortality due to the growing number of vehicles, risky behaviors, and changes in lifestyle of the general population. A sound knowledge of the geographical distribution of car traffic accidents can be considered as an approach towards the accident causation and it can be used as an administrative tool in allocating the sources for traffic accidents prevention. This study was conducted to investigate the geographical distribution and the time trend of fatal intercity car traffic accidents in Iran. To conduct this descriptive study, all Iranian intercity road traffic mortality data were obtained from the Police reports in the Statistical Yearbook of the Governor's Budget and Planning. The obtained data were for 17 complete Iranian calendar years from March 1997 to March 2012. The incidence rate (IR) of fatal ICTAs for each year was calculated as the total number of fatal ICTAs in every 100000 population in specified time intervals. Figures and maps indicating the trends and geographical distribution of fatal ICTAs were prepared while using Microsoft Excel and ArcGis9.2 software. The number of fatal car accidents showed a general increasing trend from 3000 in 1996 to 13500 in 2012. The incidence of fatal intercity car accidents has changed from six in 100000 population in 1996 to 18 in 100000 population in 2012. GIS based data showed that the incidence rate of ICTAs in different provinces of Iran was very divergent. The highest incidence of fatal ICTAs was in Semnan province (IR= 35.2), followed by North Khorasan (IR=22.7), and South Khorasan (IR=22). The least incidence of fatal ICTAs was in Tehran province (IR=2.4) followed by Khozestan (IR=6.5), and Eastern Azarbayejan (IR=6.6). The compensation cost of fatal ICTAs also showed an increasing trend during the studied period. Since an increasing amount of money was being paid yearly for the car accidents, which were in their nature preventable, the key players in road safety including governments, car manufacturers, and road developers were recommended to use GIS based accident data for a more efficient planning and budgeting towards the intercity car accidents reduction.

Information needs assessment of medical equipment offices based on Critical Success Factors (CSF) and Business System Planning (BSP) methods

Introduction: Given the ever-increasing importance and value of information, providing the management with a reliable information system, which can facilitate decision-making regarding planning, organization and control, is vitally important. This study aimed to analyze and evaluate the information needs of medical equipment offices. Methods: This descriptive applied cross-sectional study was carried out in 2010. The population of the study included the managers of statistic and medical records at the offices of vice-chancellor for treatment in 39 medical universities in Iran. Data were collected by using structured questioners. With regard to different kinds of designing information systems, sampling was done by two methods, BSP (based on processes of job description) and CSF method (based on critical success factors). The data were analyzed by SPSS-16. Results: Our study showed that 41% of information needs were found to be critical success factors of managers of office. The first priority of managers was "the number of bed and bed occupancy in hospitals". Of 29 identified information needs, 62% were initial information needs of managers (from the viewpoints of managers). Of all, 4% of the information needs were obtained through the form, 14% through both the form and database, 11% through the web site, and 71% had no sources (forms, databases, web site). Conclusion: Since 71% of the information needs of medical equipment offices managers had no information sources, the development of information system in these offices seems to be necessary. Despite the important role of users in designing the information systems (identifying 62% of information needs), other scientific methods is also needed to be utilized in designing the information systems.

Spatial distribution and prevalence of physical disabilities in the provinces of Iran

Introduction: To identify the influential social factors and spatial distribution of physical disabilities in Iran between 2006 and 2011. Materials and Methods: First, the prevalence of physical disability in each province between 2006 and 2011 was mapped via GIS. Moreover, the percentage of physical disability was estimated with regard to age, sex, and residential area. Finally, the prevalence of physical disability was estimated with regard to the afore-mentioned variables. Findings: The findings revealed that in the majority of the provinces of Iran, there was a decreasing trend in the prevalence of physical disability from 2006 to 2011. The prevalence of physical disability in the total population of the country was also decreased during these years. The results were also indicative of a higher prevalence among men than among women and also in rural residential areas than in urban areas. Conclusion: The results of this research can be used to identify the high- and low-risk areas. In addition, this information can be used for the etiology and the specification of the factors that cause the residents of some regions to get afflicted more than the others.

Spatial distribution and the prevalence of speech disorders in the provinces of Iran

Objective: To identify the spatial distribution and prevalence of speech disorder in Iran. Materials and methods: First, the prevalence of speech disorder in 2006 and 2011 was mapped via GIS for each province. Moreover, the prevalence of this disorder was calculated and classified according to age, sex, and residential area. Results: The prevalence in the majority of provinces indicated an overall decrease. Furthermore, its prevalence among the whole population of Iran in 2006 and 2011 was 2.2 and 2 per 1000 people, respectively. The highest prevalence was observed among people aged 75 years and older. Results showed that speech disorders are more prevalent among men compared to women and also among rural residents compared to those in urban areas. Conclusion: It is necessary to identify the high-risk areas in order to well organize the limited facilities to meet the actual needs of patients with speech disorder.

Wheat CBF gene family: identification of polymorphisms in the CBF coding sequence

Expression of cold-regulated genes needed for protection against freezing stress is mediated, in part, by the CBF transcription factor family. Previous studies with temperate cereals suggested that the CBF gene family in wheat was large, and that CBF genes were at the base of an important low temperature tolerance trait. Therefore, the goal of our study was to identify the CBF repertoire in the freezing-tolerant hexaploid wheat cultivar Norstar, and then to examine if the coding region of CBF genes in two spring cultivars contain polymorphisms that could affect the protein sequence and structure. Our analyses reveal that hexaploid wheat contains a complex CBF family consisting of at least 65 CBF genes of which 60 are known to be expressed in the cultivar Norstar. They represent 27 paralogous genes with 1-3 homeologous copies for the A, B, and D genomes. The cultivar Norstar contains two pseudogenes and at least 24 additional proteins having sequences and (or) structures that deviate from the consensus in the conserved AP2 DNA-binding and (or) C-terminal activation-domains. This suggests that in cultivars such as Norstar, low temperature tolerance may be increased through breeding of additional optimal alleles. The examination of the CBF repertoire present in the two spring cultivars, Chinese Spring and Manitou, reveals that they have additional polymorphisms affecting conserved positions in these domains. Understanding the effects of these polymorphisms will provide additional information for the selection of optimum CBF alleles in Triticeae breeding programs.

Antibodies to amino acid 200-239 (p200) of Ro52 as serological markers for the risk of developing congenital heart block

Maternal autoantibodies to the p200-epitope of Ro52 have been suggested to correlate with development of congenital heart block. The aim of the present study was to evaluate the clinical relevance and predictive value of p200-antibodies in high-risk pregnancies. Sera from 515 Finnish, Swedish and American women were included in the study. Sera originated from 202 mothers with an infant affected by second- or third-degree atrioventricular block (AVB), 177 mothers with rheumatic disease having infants with normal heart rate and female blood donors (n = 136). A novel serological assay for Ro52 p200-antibodies with intra- and inter-assay variability of 3% and 3.8% respectively was developed. Mothers of children affected by AVB II-III had significantly higher p200-antibody levels than mothers with rheumatic disease having children with normal heart rate (P < 0.001). In the Swedish cohort, a distinction between foetuses with normal conduction, AVB I, AVB II and III was possible. A significant difference in anti-p200 levels between AVB I and AVB II-III groups compared with foetuses with normal conduction (P < 0.05 and P < 0.01) was observed. Using p200-antibodies as a second step analysis in Ro52-positive pregnancies increased the positive predictive value for foetal cardiac involvement (AVB I, II or III) from 0.39 (0.27-0.51) to 0.53 (0.37-0.68). In conclusion, Ro52 p200-antibodies may occur in women with unaffected children, but levels are significantly higher in mothers of children with congenital heart block and are suggested as a relevant marker in evaluating the risk for foetal AV block.

Hypoglycemic neuropathy

Hypoglycemia is a relatively common condition primarily affecting diabetic patients treated with insulin or other hypoglycemic drugs and insulinoma patients. Clinical experience and experimental studies show that hypoglycemia may cause alterations both in the central (CNS) and the peripheral (PNS) nervous system. Hypoglycemic effects on the CNS include various symptoms such as irritability and lack of concentration, disruption of cognitive functions, convulsions and unconsciousness. As for pathology, a loss of neurons has been noted, being more obvious in the cerebral cortex and the hippocampus than in the brain stem, cerebellum and spinal cord. Myelin damage and glial changes have also been observed in the CNS. The development of pathological changes in the brain has mainly been studied on autopsy material from patients who died in insulin coma and in animals exposed to a severe hypoglycemia and showing an isoelectric electroencephalogram. It has been suggested that hypoglycemic loss of neurons in the brain is related to excititoxic actions of aspartate on N-methyl-D-aspartate receptors. With respect to the PNS, scattered clinical observations in humans and experimental studies in animals show that hypoglycemia causes a distal axonopathy including both degenerative and regenerative events. In this respect, motor axons seem to be more vulnerable than sensory axons. Animal experiments show that a peripheral neuropathy may develop even in cases with a mild hypoglycemia compatible with a generally normal behavior. The cellular mechanisms behind the development of hypoglycemic PNS alterations are unknown. To elucidate the pathophysiology of hypoglycemic neuropathy more basic research is needed.

Hypoglycaemic neuropathy in diabetic BB/Wor rats treated with insulin implants affects ventral root axons but not dorsal root axons

It is believed that hyperglycaemia underlies diabetic neuropathy. However, low blood glucose values may also cause pathological changes in peripheral nerves and in neuronal perikarya. This study examined spinal roots, dorsal root ganglia and the ventral horn at the segmental level L5 in long-term insulin-treated eu-/hypoglycaemic diabetic rats with an obvious plantar nerve pathology. The purpose was to determine whether hypoglycaemic neuropathy affects sensory and/or motor neurons at root and/or perikaryal levels. Electron microscopic examination of dorsal roots from eu-/hypoglycaemic rats showed a normal qualitative morphology and normal numbers of unmyelinated and myelinated axons. In ventral roots the picture varied. Whereas two rats exhibited an essentially normal morphology, three rats presented moderate or marked signs of pathology such as clusters of small and medium-sized myelinated axons, medium-sized myelinated axons with abnormally thin sheaths, large unmyelinated axons and signs of past or ongoing axonal degeneration. Light microscopic examination of the L5 dorsal root ganglion and ventral horn showed a qualitatively normal picture in eu-/hypoglycaemic rats and the mean number of large ventral horn neurons per section was normal. These results suggest that the type of eu-/hypoglycaemia examined here affects ventral root axons but not dorsal root axons, that the degree of ventral root pathology is variable and that sensory and motor neuron perikarya do not appear to be affected.

Hypoglycaemic neuropathy: occurrence of axon terminals in plantar skin and plantar muscle of diabetic BB/Wor rats treated with insulin implants

It is generally believed that diabetic neuropathy is due to chronic hyperglycaemia. However, experience from insulinoma patients and experimental studies show that hypoglycaemia may also cause neuropathy. Accordingly, the plantar nerves of diabetic eu-/hypoglycaemic BB/Wor rats treated with insulin implants exhibit a distinct neuropathy. To what extent hypoglycaemic neuropathy affects axon terminals in skin and muscle is unknown. In the present study we examine the occurrence of epidermal axon profiles and the neuropeptide calcitonin gene-related peptide (CGRP) in plantar skin, and of end plate axon terminals in a plantar muscle of diabetic BB/Wor rats subjected to long periods of hypoglycaemia. The number of protein gene product-immunoreactive axon profiles was found to be normal in heel skin biopsy specimens from eu-/hypoglycaemic rats, but many profiles were short and thin. The content of CGRP in the skin biopsy samples was significantly below normal. After staining with antibodies against the vesicular acetylcholine transporter protein, the occurrence of end plate axon terminals was significantly reduced in sections from the flexor hallucis brevis muscle of eu-/hypoglycaemic rats. Moreover, the end plate axon terminals tended to be abnormally small in these rats. We conclude that the hypoglycaemic neuropathy seen in plantar nerve trunks of diabetic BB/Wor rats treated with insulin implants is accompanied by mild alterations in the epidermal innervation of plantar skin and a more obviously abnormal nerve terminal pattern in plantar muscle.

Neuropathy in diabetic BB/Wor rats treated with insulin implants

To elucidate the pathophysiology of diabetic neuropathy many workers have examined nerve specimens from diabetic rats. While most workers found that animals with high blood glucose levels develop neuropathy, some researchers report that the peripheral nerves are normal in hyperglycaemic rats. Hypoglycaemia may also cause neuropathy. Some workers suggest that neuropathy is linked to fluctuations of the blood glucose level. In the present study we examine plantar nerves of diabetic BB/Wor rats maintained on an eu-/hyperglycaemic or an eu-/hypoglycaemic regime with insulin implants. Treatment with implants worked well. Light microscopic examination of nerve fibres in non-diabetic control rats and in eu-/hyperglycaemic diabetic rats showed a normal picture. Preparations from eu-/hypoglycemic rats showed irregular myelin sheaths and signs of Wallerian degeneration. The lengths and diameters of the largest internodes were significantly subnormal. We conclude, that periodic moderate hypoglycaemia, but not periodic moderate hyperglycaemia, elicits neuropathy in diabetic BB/Wor rats treated with insulin implants.

Hypoglycaemic neuropathy in BB/Wor rats treated with insulin implants: electron microscopic observations

Insulin-dependent diabetes mellitus is a chronic metabolic disease that causes long-term secondary complications such as neuropathy. The occurrence of diabetic neuropathy has generally been thought of as being associated with hyperglycaemia. However, in a previous light microscopic examination of plantar nerves in diabetic BB/Wor rats treated with insulin implants we found that eu-/hyperglycaemic rats present a normal picture, whereas eu-/hypoglycaemic rats show severe changes. The aim of the present work is to supplement our previous light microscopic report with electron microsocpic data from the lateral plantar nerve of normal, eu-/hyperglycaemic and eu-/hypoglycaemic BB/Wor rats. Under the electron microscope lateral plantar nerves collected from eu-/hyperglycaemic rats presented a qualitatively normal picture. In addition, the fibre numbers and the size distribution of the myelinated fibres were normal. In contrast, specimens from eu-/hypoglycaemic BB/Wor rats showed severe qualitative changes, interpreted as signs of axonal de- and regeneration. The total number of axons was somewhat subnormal and the sizes of the myelinated fibres were strongly shifted towards smaller diameters. These data confirm our previous light microscopic observations. We conclude that eu-/hypoglycaemic BB/Wor rats treated with insulin implants, but not similarly treated eu-/hyperglycaemic animals, develop a neuropathy in their plantar nerves.