Regulated cell death pathways in the sodium iodate model: Insights and implications for AMD

The sodium iodate (NaIO3) model of increased oxidative stress recapitulates dry AMD features such as patchy RPE loss, secondary photoreceptors, and underlying choriocapillaris death, allowing longitudinal evaluation of the retinal structure. Due to the time- and dose-dependent degeneration observed in diverse animal models, this preclinical model has become one of the most studied models. The events leading to RPE cell death post- NaIO3 injection have been extensively studied, and here we have reviewed different modalities of cell death, including apoptosis, necroptosis, ferroptosis, and pyroptosis with a particular focus on findings associated with in vivo and in vitro NaIO3 studies on RPE cell death. Because the fundamental cause of vision loss in patients with dry AMD is the death of these same cells affected by NaIO3, studies using NaIO3 can provide valuable insights into RPE and photoreceptor cell death mechanisms and can help understand mechanisms behind RPE degeneration in AMD.

The retinal pigment epithelium in Sorsby Fundus Dystrophy shows increased sensitivity to oxidative stress-induced degeneration

Sorsby Fundus Dystrophy (SFD) is a rare inherited autosomal dominant macular degeneration caused by specific mutations in TIMP3. Patients with SFD present with pathophysiology similar to the more common Age-related Macular Degeneration (AMD) and loss of vision due to both choroidal neovascularization and geographic atrophy. Previously, it has been shown that RPE degeneration in AMD is due in part to oxidative stress. We hypothesized that similar mechanisms may be at play in SFD. The objective of this study was to evaluate whether mice carrying the S179C-Timp3 mutation, a variant commonly observed in SFD, showed increased sensitivity to oxidative stress. Antioxidant genes are increased at baseline in the RPE in SFD mouse models, but not in the retina. This suggests the presence of a pro-oxidant environment in the RPE in the presence of Timp3 mutations. To determine if the RPE of Timp3 mutant mice is more susceptible to degeneration when exposed to low levels of oxidative stress, mice were injected with low doses of sodium iodate. The RPE and photoreceptors in Timp3 mutant mice degenerated at low doses of sodium iodate, which had no effect in wildtype control mice. These studies suggest that TIMP3 mutations may result in a dysregulation of pro-oxidant-antioxidant homeostasis in the RPE, leading to RPE degeneration in SFD.

Modulation of mtDNA copy number ameliorates the pathological consequences of a heteroplasmic mtDNA mutation in the mouse

Heteroplasmic mtDNA mutations typically act in a recessive way and cause mitochondrial disease only if present above a certain threshold level. We have experimentally investigated to what extent the absolute levels of wild-type (WT) mtDNA influence disease manifestations by manipulating TFAM levels in mice with a heteroplasmic mtDNA mutation in the tRNA^Ala gene. Increase of total mtDNA levels ameliorated pathology in multiple tissues, although the levels of heteroplasmy remained the same. A reduction in mtDNA levels worsened the phenotype in postmitotic tissues, such as heart, whereas there was an unexpected beneficial effect in rapidly proliferating tissues, such as colon, because of enhanced clonal expansion and selective elimination of mutated mtDNA. The absolute levels of WT mtDNA are thus an important determinant of the pathological manifestations, suggesting that pharmacological or gene therapy approaches to selectively increase mtDNA copy number provide a potential treatment strategy for human mtDNA mutation disease.

Need of The Ministry of Health in Federal Democratic Republic of Nepal

The constitution of Nepal provides appointing a council of ministers both at federal and provincial levels without defining portfolios. There is a political agreement that MOH will be retained at the federal level. This article draws evidences around the world to meet health needs of Nepalese, the role of provincial ministry of health and coordinating structure at district/local level. The constitution emphasises on health and pronounced in 46 articles which provides guidance for the creation of federalized governance levels at federal, provincial and local levels. Retaining ministry of health at federal level without creating devolved structure at province and local levels in health sector will create difficulty in translating the spirit of the constitution and may not be effective in addressing health issues nationally and meeting global achievements like SDGs. It is suggested to establish an elaborate health system accordingly in Nepal to ensure constitutional mandate of health as a basic human right.

CD40 signaling drives B lymphocytes into an intermediate memory-like state, poised between naïve and plasma cells

Immunological memory comprising of antigen-specific B and T cells contributes to the acquisition of long-term resistance to pathogens. Interactions between CD40 on B cells and CD40L on T cells are responsible for several aspects of acquired immune responses including generation of memory B cells. In order to gain insights into events leading to memory B cell formation, we analyzed the genome-wide expression profile of murine naive B cells stimulated in the presence of anti-CD40. We have identified over 8,000 genes whose expression is altered minimally 1.5-fold at least at one time point over a 3-day time course. The array analysis indicates that changes in expression level of maximum number of these genes occur within 24 h of anti-CD40 treatment. In parallel, we have studied the events following CD40 ligation by examining the expression of known regulators of naive B cell to plasma cell transition, including Pax5 and BLIMP1. The expression profile of these regulatory genes indicates firstly, that CD40 signaling activates naïve B cells to a phenotype that is intermediate between the naive and plasma cell stages of the B cell differentiation. Secondly, the major known regulator of plasma cell differentiation, BLIMP1, gets irreversibly downregulated upon anti-CD40 treatment. Additionally, our data reveal that CD40 signaling mediated BLIMP1 downregulation occurs by non-Pax5/non-Bcl6 dependent mechanisms, indicating novel mechanisms at work that add to the complexity of understanding of B cell master regulatory molecules like BLIMP1 and Pax5.

Cling wrap, an innovative intervention for temperature maintenance and reduction of insensible water loss in very low-birthweight babies nursed under radiant warmers: a randomized, controlled trial

AIM

The value of polythene film ('cling wrap') to improve thermal control and reduce postnatal weight loss in preterm, very low-birthweight babies was investigated.

METHODS

Consecutively born babies with birthweights between 750 and 1500 g were stratified by birthweight (<1250 g, 1251-1500 g) and randomised either to the cling wrap (CW) or no cling wrap (NCW) group. The baby bassinette of the RW was covered with cling wrap up to the level of the neck in the CW group for the 1st 7 days. The primary outcome variables were the incidence of hypothermia (axillary temperature < or = 36 degrees C) after initial stabilisation during the first 7 days and cumulative weight loss (percentage of birthweight) at 48 hours of age.

RESULTS

Of 51 babies, 26 were randomised to the CW and 25 to the NCW group. None of the babies in the CW group developed hypothermia in the 1st 7 days but 36% in the NCW group (p = 0.001) did. Babies who were hypothermic on admission took less time to reach normal temperature in the CW group. Cumulative weight loss in the 1st 48 hours was 5.0 + 5.6% in the CW group and 8.6 + 7.0% in the NCW group (p = 0.06).

CONCLUSION

Use of CW might be a simple method of maintaining temperature in very low-birthweight babies in developing countries.

Mini-implants for retraction, intrusion and protraction in a Class II division 1 patient

This case report demonstrates the clinical utility and versatility of mini-implants in carrying out different types of tooth movement in a 14-year-old boy with a 'severe' Class II division 1 malocclusion. Mini-implants were placed for 'en masse' retraction and intrusion of maxillary anterior teeth and for lower molar protraction. More than 11 mm of maxillary incisor retraction was achieved together with 3 mm of intrusion. There was significant reduction in the dentoalveolar protrusion and retraction of the upper lip, which resulted in decreased mentalis strain and improved chin projection. Cephalometric superimposition and panoramic radiographs showed no anchorage loss and good occlusion at the end of treatment.

Hypocalcemia in the newborn

Healthy term babies undergo a physiological nadir in serum calcium levels by 24-48 hours of age. This nadir may be related to the delayed response of parathyroid and calcitonin hormones in a newborn. This nadir may drop to hypocalcemic levels in high-risk neonates including infants of diabetic mothers, preterm infants and infants with perinatal asphyxia. This early onset hypocalcemia which presents within 72 hours, requires treatment with calcium supplementation for at least 72 hours. In contrast late onset hypocalcemia usually presents after 7 days and requires long term therapy. Ionized calcium is crucial for many biochemical processes and total serum calcium is a poor substitute for the diagnosis of hypocalcemia.

Zinc uptake, oxidative stress and the FNR-like proteins of Lactococcus lactis

Lactococcus lactis ssp. cremoris MG1363 contains two FNR homologues, FlpA and FlpB, encoded by the distal genes of two paralogous operons (orfX(A/B)-orfY(A/B)-flpA/B). An flpA flpB double mutant strain is hypersensitive to hydrogen peroxide and has a depleted intracellular Zn(II) pool. The phenotypes of the flp mutant strains suggest that FlpA and FlpB control the expression of high and low affinity ATP-dependent Zn(II) uptake systems, respectively. Plate tests revealed that expression from a orfX(B)::lac reporter was activated by Cd(II), consistent with other Zn(II)-regulated systems. The link between a failure to acquire Zn(II) and hypersensitivity to oxidative stress suggests that Zn(II) may be required to protect vulnerable protein thiols from oxidation.