Two distinct types of dying back axonal degeneration in vitro.

AIMS: In many neurodegenerative diseases and following traumas, dying back degeneration is a common phenomenon that aggravates the pathology and may eventually lead to death of the affected neurone. We aimed to investigate the mechanism of dying back degeneration with an in vitro axonal injury model. METHODS: We cultured adult mouse dorsal root ganglion neurones and with a precise laser beam, cut the axons they extended. Preparations were imaged continuously and images were analysed to describe and quantify ensuing events. Potential contributions of calpains and caspases to the degeneration were explored using specific inhibitors and immunohistochemistry. In vivo implications of the results were sought in nerve sections after sciatic nerve cut. RESULTS: The proximal part of the transected axons went under basically two types of dying back degeneration, fragmentation and retraction. In fragmentation the cytoplasm became condensed and with concomitant axial collapse the axon disintegrated into small pieces. In retraction, the severed axon was pulled back to the soma in an organized manner. We demonstrated that fragmentation was associated with a high risk of cell death, while survival rate with retraction was as high as those of uninjured neurones. Regeneration of transected axon was more likely after retraction than following fragmentation. Activities of caspase-3 and calpains but not of caspase-6 were found linked with retraction and regeneration but not with the fragmentation. CONCLUSIONS: This study describes two quite distinct types of dying back degeneration that lead an injured neurone to quite different fates.

Effects of pinealectomy and exogenous melatonin on the brains, testes, duodena and stomachs of rats.

BACKGROUND: It is generally agreed that physiological levels of melatonin, a hormone secreted by the pineal gland, are important in protecting against oxidative stress-induced tissue damage. AIM: We investigated the effects that pinealectomy and the administration of exogenous melatonin have on the brains, testes, duodena and stomachs of rats. MATERIALS AND METHODS: Pinealectomized (Px) and sham-operated (non-Px) rats were used. We evaluated structural changes, and catalase (CAT), reduced glutathione (GSH), super oxide dismutase (SOD) and malondialdehyde (MDA) levels. The rats were divided into the following five groups (eight rats in each group): sham (non-Px), Px+ vehicle, Px+ melatonin (10 mg/kg given daily intraperitoneally for a week), melatonin and ethyl alcohol. RESULTS: The antioxidant levels in the tissue of Px rats were significantly lower than in those of the sham group. Administering melatonin significantly increased antioxidant levels (p < 0.05). The Px rats also showed a significant increase in MDA levels when compared to the sham group, and administering melatonin to the Px rats significantly reduced their MDA levels (p < 0.05). The severity of caspase-3 staining was lower in the Px+ melatonin group than in the Px+vehicle group. CONCLUSIONS: These findings suggest that significantly more oxidative and structural changes occur in rats' brains, spinal cords and testes after pinealectomy, but that this can be diminished by melatonin treatment. However, Px does not have important effects on the duodenum and stomach.

Laboratory parameters associated with prolonged hospital length of stay in COVID-19 patients in Johannesburg, South Africa.

BACKGROUND: Coronavirus disease (COVID-19) has imposed unprecedented stressors on South Africa (SA)'s healthcare system. Superimposed on the country's quadruple burden of disease, pandemic-related care further exposes existing inequities. Some of these inequities are specific to hospital-based inpatient services, such as the geographical maldistribution of hospital beds, lack of oxygen supplies and assisted ventilation, and scarcity of trained healthcare workers. Certain high-risk groups, such as individuals with cardiometabolic comorbidity, are likely to develop severe COVID-19 disease requiring hospitalisation with potential for a prolonged length of stay (LoS). It may be helpful for health authorities to identify those at risk for prolonged LoS to facilitate appropriate health systems planning. OBJECTIVES: To identify hospital admission laboratory parameters associated with a hospital stay >14 days in patients with COVID-19 pneumonia. METHODS: A retrospective observational study design was used. Laboratory data were obtained from an SA private laboratory for 642 inpatients with suspected or confirmed COVID-19 pneumonia, comprising 7 months of admission laboratory data from six private hospitals in Johannesburg, Gauteng Province. RESULTS: Of 642 hospital admissions for pneumonia, 497 were confirmed to have COVID-19 infection (reverse transcription-polymerase chain reaction test positive). In the COVID-19-positive group, hospital LoS was prolonged in 35.4% of admissions. Univariate analysis demonstrated an association with the following risk factors for prolonged LoS: older age; male sex; high serum creatinine, sodium (Na), chloride, potassium and urea levels and low estimated glomerular filtration rate; raised white blood cell count, lymphopenia, neutrophilia and an elevated neutrophil-to-lymphocyte ratio (NLR); and elevated levels of D-dimers, interleukin-6 (IL-6), and procalcitonin (PCT). The strongest univariate associations (relative risk (RR) ≥2.0) with a hospital stay >14 days were high Na levels, NRL >18, high PCT levels and IL-6 >40 pg/mL. On multivariable analysis, the following factors remained significantly associated with prolonged LoS: older age (RR 1.015 per year of age; 95% confidence interval (CI) 1.005 - 1.024); hypernatraemia (RR 1.80; 95% CI 1.25 - 2.60); hyperkalaemia (RR 1.61; 95% CI 1.18 - 2.20); and neutrophilia (RR 1.47; 95% CI 1.15 - 1.88). CONCLUSIONS: COVID-19 pandemic preparedness requires hospital-based inpatient care to be prioritised in resource-limited settings, and availability of beds and prompt admissions are essential to ensure good clinical outcomes. In this study of COVID-19 patients admitted with pneumonia, multivariable analysis showed older age, hypernatraemia, hyperkalaemia and neutrophilia to be associated with LoS >14 days. This may assist with healthcare systems planning.

Differential analysis of effect of high glucose level in the development of neuropathy in a tissue culture model of diabetes mellitus: role of hyperosmolality.

To analyse the contributions of metabolic toxicity of high glucose level and accompanying hyperosmolality to the development of diabetic neuropathy, mouse dorsal root ganglion (DRG) cultures were used. DRGs from postnatal day 7 mice were embedded in collagen gel and incubated in RPMI 1640 culture medium with increasing concentrations of glucose or equimolar amounts of mannitol which would create similar osmolalities. Outgrowth of axons from the peripheral nerve attached to DRG and migration of cells into the gel were quantified. The extent of cell death, apoptosis and mitosis among the migrating cells and apoptosis among DRG neurons following exposure to high glucose or mannitol were also evaluated. The growth of axons was almost equally affected by increasing concentrations of glucose or mannitol up to 395 mOsm/kg H (2)O. Number of migrating cells was close to control values with mannitol between 340-395 mOsm/kg H (2)O while high concentrations of glucose always decreased it. Exposure to high glucose or mannitol led to increased proportions of dead and apoptotic migrating cells and apoptotic DRG neurons. Mitotic activity was also negatively affected by high glucose or mannitol. While glucose proved significantly more detrimental to migrating cells than mannitol in the latter tests, the extent of apoptosis was similar among DRG neurons in both conditions. In conclusion, the contribution of hyperosmolality to the development of neuropathy in high glucose condition appears to be quite significant. The peripheral nerve cells and neurons, however, are differentially affected by hyperosmolality and metabolic toxicity of high glucose.

Effects of caffeic acid phenethyl ester on cerebral cortex: structural changes resulting from middle cerebral artery ischemia reperfusion.

Overproduction of free radicals is important in the pathogenesis of the cerebral damage induced by ischemia reperfusion. Caffeic acid phenethyl ester, an active component of propolis extract, exhibits antioxidant properties. The study was carried out in 16 male Wistar albino rats, divided into two groups: ischemia reperfusion and ischemia reperfusion with caffeic acid phenethyl ester. The middle cerebral artery was occluded for 60 min with an intraluminal suture, followed by 24-h reperfusion. In this study, widespread infarcted areas, red neurons (eosinophilic degeneration), pyknotic cells, vacuolization and neuroglial cell infiltration were observed in the cerebral cortex in the ischemia reperfusion group. In the caffeic acid phenethyl ester group, slightly infarcted areas were observed and neuroglial cell infiltration was not determined. Congestion of choroid plexus and pia mater was found more severe in the ischemia reperfusion group than in the caffeic acid phenethyl ester group. In the caffeic acid group, neuroglial cell activation was rare. Vacuolization, an indication of brain edema, was prevented by caffeic acid phenethyl ester. In the present study, we showed that pre-treatment with a single i.p. injection of caffeic acid phenethyl ester at 50 microM/kg dose reduced the structural changes.

Orthogonal thiol-ene 'click' reactions: a powerful combination for fabrication and functionalization of patterned hydrogels.

A combination of 'orthogonal' thiol-ene 'click' reactions is utilized for fabrication and functionalization of micro-patterned hydrogels. A furan-protected maleimide-containing parent copolymer is partially activated via the retro Diels-Alder reaction to obtain an 'orthogonally' functionalizable copolymer, where the different functional groups can be exploited for multi-functionalization or fabrication of functional hydrogels using combination of the nucleophilic and radical thiol-ene reactions.

Intravenous pulse cyclophosphamide therapy in focal segmental glomerulosclerosis.

AIMS: We herein report the results of intravenous pulse cyclophosphamide (IVCP) therapy of 5 patients with steroid-resistant focal segmental glomerulosclerosis (FSGS). All patients had been treated with oral and intravenous pulse methylprednisolone and failed to respond to steroids from onset and were considered as primary steroid-resistant. Before starting IVCP, all patients were also treated with other immunosuppressive drugs with or without steroids, but none of them responded to such therapies and no patient had any NPSH2 gene mutations. METHODS: IVCP was given monthly at a dose of 500 mg/m2 for 6 months. At the end of 6 months, IVCP was discontinued in case there was no response. Otherwise, IVCP was continued for every 2 months. Oral prednisone was given concurrently at 60 mg/m2 daily for 6 weeks and then 40 mg/m2 on alternate days for 4 weeks. Prednisone was then tapered to 10 mg/m2 alternate days and continued during the therapy period. RESULTS: Only 1 of these patients achieved remission after IVCP while 4 patients showed no response to IVCP. 2 patients who did not achieve remission progressed to end-stage renal disease (ESRD) and 2 others who had not been treated with cyclosporine before underwent cyclosporine therapy. None of our patients has suffered from adverse effects of IVCP. CONCLUSION: We found that IVCP had a limited beneficial effect in treatment of steroid-resistant FSGS and it may be suggested that IVCP can be tried to treat steroid-resistant patients, also for patients with primary steroid resistance and those who do not respond to other immunosuppressive therapies.

Relationship between chronic inflammation and cardiovascular risk factors in children on maintenance hemodialysis.

Cardiovascular disease is one of the most important causes of morbidity and mortality in children with end-stage renal failure. Chronic inflammation and malnutrition have been suggested to be risk factors for cardiovascular disease. However, to date, biomarkers of inflammation have not been well studied in children. The aim of this study was to investigate the relation between chronic inflammation and cardiovascular risk factors in children on hemodialysis therapy. Twenty-seven patients on hemodialysis (14 girls, 13 boys) of mean age 15.3 +/- 2.4 years and 20 healthy children (13 girls, 7 boys) of mean age 14.3 +/- 2.7 years were included the study. C-reactive protein (CRP), albumin, prealbumin, transferrin, ferritin, and fibrinogen were measured as the markers of inflammation. The levels of CRP, ferritin, and erythrocyte sedimentation rate among hemodialysis patients were significantly higher than those of control subjects (P < .001 for all). Albumin and transferrin levels were found to be lower than those of control group (P = .02 and P < .001, respectively). CRP levels were negatively correlated with albumin, prealbumin, apoprotein A1, HDL, and hemoglobin levels, and positively correlated with erythropoietin/Htc ratios. This study suggests that hemodialyzed children are exposed to chronic inflammation. In addition, CRP may be an indicator of chronic inflammation related to cardiovascular risk factors, such as malnutrition, dyslipidemia, and anemia. In conclusion, we suggest that the risk of cardiovascular disease could be reduced by defining markers of chronic inflammation and malnutrition in hemodialyzed children and by taking necessary measures at an early stage.

Relationship between leptin and bone mineral density in renal transplant recipients.

INTRODUCTION: Leptin plays an important role in regulating appetite and energy expenditure and also functions in the neuroendocrine, hematopoietic, and immune systems, among others. Leptin may be involved in modulating bone mineralization. The relationship between leptin and bone mineral density (BMD) is not clear. This study examined the relationship between BMD and serum leptin levels in renal transplant recipients. MATERIALS AND METHODS: Forty-one patients (28 men and 13 women; age 16 to 55 years) were grouped according to percentile of serum leptin level hypoleptinemic (<5th percentile, n = 14), normoleptinemic (between the 5th and 95th percentiles, n = 19), or hyperleptinemic (>95th percentile, n = 8). The patients also were grouped according to lumbar z score) and total femur z scores (>-2 vs <-2 for both). RESULTS: The groups with different leptin statuses were compared with respect to age, sex distribution, and body mass index. Mean lumbar z score and mean lumbar BMD were higher in the hyperleptinemic group than in the normo- and hypoleptinemic groups (P < .05 for all). Considering the 42 patients overall, those with lumbar z scores >-2 had higher mean serum leptin/BMI than those with lumbar z scores <-2 (0.55 +/- 0.65 vs 0.18 +/- 0.23, respectively, P < .05). Serum leptin/BMI ratio was correlated with lumbar z score (r = .38, P < .05) and lumbar BMD (r = .32, P < .05). CONCLUSION: In conclusion, the data indicate that elevated leptin level is associated with increased bone mass at lumbar sites in renal transplant recipients. This suggest that increased leptin has a bone-sparing effect, especially in the lumbar region, in this patient group.

Mycophenolate mofetil in children with multidrug-resistant nephrotic syndrome.

AIM: The aim of the present study is to report our clinical experiences with MMF in problematic children with chronic glomerulonephritis resistant to corticosteroids and/or other immunosuppressive drugs. PATIENTS AND METHODS: Ten patients with chronic glomerulonephritis resistant to treatment with corticosteroids and other immunosuppressive drugs were treated with mycophenolate mofetil (MMF). Causes of chronic glomerulonephritis were mesangial proliferative glomerulonephritis (4), membranoproliferative glomerulonephritis (3), chronic sclerosing glomerulonephritis (1), focal segmental glomerulosclerosis (1), diffuse endo- and extracapillary proliferative glomerulonephritis (1). MMF 15 mg/kg was used in combination with low-dose corticosteroids and angiotensin-converting enzyme inhibitors. RESULTS: During 24 weeks of MMF therapy, no significant changes were detected in mean serum creatinine, albumin and proteinuria. Severe leukopenia was seen in 1 patient. Additional adverse effects, including nausea and diarrhea, were observed in another patient when the dosage was increased to 20 mg/kg per day. During MMF treatment proteinuria decreased slightly without remission in 6 of 10 patients. CONCLUSION: Further data and clinical trials are needed to evaluate the possible role of MMF in the treatment of chronic glomerulonephritis of similar etiologies in pediatric patients.

Recurrent supraventricular tachycardia in a newborn treated with amiodarone: is hyperkalemia the apparent cause?

Supraventricular tachycardia (SVT) is the most common type of arrhythmia observed in children, especially in newborns. Infants with severe SVT must be treated immediately with first-line drugs such as amiodarone. There are some minor and major side effects of amiodarone in this patient group, but no associated electrolyte disorders have been observed. This report describes a newborn whose recurrent SVT attacks during amiodarone treatment were suspected to have been caused by hyperkalemia.

Metronidazole-induced encephalopathy in a uremic patient: a case report.

A variety of neurologic disorders may develop in patients with chronic renal failure. Drug toxicity must be thought of in the differential diagnosis of these disorders. We report a case with renal failure developing serious neurotoxicity after metronidazole use.

Adult metachromatic leukodystrophy: three cases with normal nerve conduction velocities in a family.

Here, we report three cases of late onset metachromatic leukodystrophy (MLD) within a family. The patients presented with psychiatric disturbances and dementia. The arylsulphatase A (ASA) level in leucocytes was zero in all the patients. The cranial magnetic resonance imaging (MRI) revealed bilateral symmetrical demyelination but the nerve conduction velocities were normal in all three cases. The clinical, biochemical, imaging and electrophysiological data of the family has been discussed.

Effects of chronic ethanol consumption on alpha-adrenergic-induced contractions and endothelium-dependent relaxations in rat thoracic aorta.

The effects of chronic oral administration of ethanol (7.2% daily during 24 weeks) on the contractions induced by phenylephrine (Phe) and the endothelium-dependent relaxation responses to acetylcholine (ACh) were studied in rat thoracic aorta. Ethanol pretreatment significantly attenuated the contractile responses to Phe, resulting in parallel shift of the concentration-response curve to the right. EC(50)values of Phe were 64.6+/-11.2 and 95.5+/-8.5 nmol l(-1)in control and ethanol-fed rats, respectively. On the other hand, either calcium-induced contractions or relaxation responses to ACh and sodium nitroprusside were similar in the vessels of the control and ethanol-treated rats. These results suggest that chronic ethanol ingestion significantly attenuates the alpha(1)-adrenergic-induced contractions but does not affect the relaxation responses mediated by nitric oxide in rat aortic rings.