Investigating the link between miR-34a-5p and TLR6 signaling in sepsis-induced ARDS

Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) are lung complications diagnosed by impaired gaseous exchanges leading to mortality. From the diverse etiologies, sepsis is a prominent contributor to ALI/ARDS. In the present study, we retrieved sepsis-induced ARDS mRNA expression profile and identified 883 differentially expressed genes (DEGs). Next, we established an ARDS-specific weighted gene co-expression network (WGCN) and picked the blue module as our hub module based on highly correlated network properties. Later we subjected all hub module DEGs to form an ARDS-specific 3-node feed-forward loop (FFL) whose highest-order subnetwork motif revealed one TF (STAT6), one miRNA (miR-34a-5p), and one mRNA (TLR6). Thereafter, we screened a natural product library and identified three lead molecules that showed promising binding affinity against TLR6. We then performed molecular dynamics simulations to evaluate the stability and binding free energy of the TLR6-lead molecule complexes. Our results suggest these lead molecules may be potential therapeutic candidates for treating sepsis-induced ALI/ARDS. In-silico studies on clinical datasets for sepsis-induced ARDS indicate a possible positive interaction between miR-34a and TLR6 and an antagonizing effect on STAT6 to promote inflammation. Also, the translational study on septic mice lungs by IHC staining reveals a hike in the expression of TLR6. We report here that miR-34a actively augments the effect of sepsis on lung epithelial cell apoptosis. This study suggests that miR-34a promotes TLR6 to heighten inflammation in sepsis-induced ALI/ARDS.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-023-03700-1.

Factors predictive of Ponseti casting for treating clubfoot: analysis of Bayesian Poisson regression model

OBJECTIVE

Clubfoot is a growing public health concern in Bangladesh, with the incidence of approximately 0.64 to 6.8 in every 1000 live births. For over a decade, Ponseti method has been considered a gold standard for treating the clubfoot. Despite few studies have been estimating the number of casts required to correct the clubfoot deformities by Ponseti method, the subject of interest has always remained. Therefore, this current study aimed to investigate the significant predictive factors for the number of casts required to correct congenital clubfoot.

PATIENTS AND METHODS

In this retrospective cohort study, we used Bayesian Poisson Regression Model to investigate the influencing factors that could predict how many casts are needed to correct the clubfoot. We included 69 patients with 99 affected feet, who completed their corrective phase of treatment in the Ponseti method. For this cohort study, we integrated only pre-tenotomy casting data with no age restrictions. We used Bayesian Poisson regression analysis technique to estimate the predictive factors.

RESULTS

In Bayesian Poisson model, age was the most influencing predictive factor (24.3%) for increasing the number of castings to correct the clubfoot deformity. The clubfoot offspring of the ≤1-year-old was positive, and the incidence rate increased significantly with the casting number. The number of Ponseti casts in male clubfoot children was 28% higher than in female, and this was marginally statistically significant. There was no marked change estimated in the pattern of clubfoot, foot involvement and Pirani score of the severity.

CONCLUSIONS

We concluded that the age factor may influence the number of casts required for the correction of clubfoot and specifically ≤ 1-year-old children are highly impacted. Treating clubfoot at an early age is suggested in this study to increase the success of clubfoot treatment and decrease the risk of relapse.

P16 An audit of elderly patients with a femoral fracture: is the quality of care received by patients affected by where in the femur the fracture occurs?

Introduction

Elderly patients with femoral fractures are often frail and require a multidisciplinary approach to optimise medical care, rehabilitation and prevention of further injury. Previously, neck of femur fracture patients were the focus of such an approach, but NICE and BOAST guidelines emphasise extending this care to other elderly trauma patients.

Methods

A retrospective analysis of 43 patients over 60 years old at Gloucestershire Hospitals NHS Foundation Trust in 2019 with a femoral fracture other than a neck of femur fracture. BOAST guideline standards were surgery within 36 hours, orthogeriatric assessment within 72 hours, a documented ceiling of treatment, falls risk assessment, bone health review, nutritional assessment and physiotherapy review.

Results

Our study showed worse outcomes in all standards for patients with femoral shaft, distal femur and periprosthetic femur fractures compared to neck of femur fractures: surgery within 36 hours (63.9% vs. 66%); orthogeriatric assessment within 72 hours (32.6% vs. 91.9%); falls risk assessment (76.7% vs. 99.6%); bone health review (41.9% vs. 99.7%); nutritional assessment (55.8% vs. 99.6%); physiotherapy review (97.7% vs. 98.9%). The group also had worse outcomes for average length of stay (19 days vs. 14 days) and 30 day mortality (9.3% vs. 8.6%).

Discussion

Our study showed a discrepancy in care received by elderly patients with femoral fractures other than neck of femur. We will introduce a proforma for all femoral fractures, present our findings to orthogeriatric, bone health and physiotherapy teams to involve them in the care of such patients and re-audit following these recommendations.

Inhibition of miRNA-34a Promotes M2 Macrophage Polarization and Improves LPS-Induced Lung Injury by Targeting Klf4

Acute respiratory distress syndrome (ARDS) is an outcome of an accelerated immune response that starts initially as a defensive measure, however, due to non-canonical signaling, it later proves to be fatal not only to the affected tissue but to the whole organ system. microRNAs are known for playing a decisive role in regulating the expression of genes involved in diverse functions such as lung development, repair, and inflammation. In-silico analyses of clinical data and microRNA databases predicted a probable interaction between miRNA-34a (miR-34a), mitogen-activated protein kinase 1 (ERK), and kruppel like factor 4 (Klf4). Parallel to in silico results, here, we show that intra-tracheal instillation of lipopolysaccharides (LPS) to mice enhanced miR-34a expression in lung macrophages. Inhibition of miR-34a significantly improved lung histology, whereas over-expression of miR-34a worsened the lung injury phenotype. miR-34a over-expression in macrophages were also demonstrated to favour pro-inflammatory M1 phenotype and inhibition of M2 polarization. In a quest to confirm this likely interaction, expression profiles of Klf4 as the putative target were analyzed in different macrophage polarizing conditions. Klf4 expression was found to be prominent in the miR-34a inhibitor-treated group but down-regulated in the miR-34a mimic treated group. Immuno-histopathological analyses of lung tissue from the mice treated with miR-34a inhibitor also showed reduced inflammatory M1 markers as well as enhanced cell proliferation. The present study indicates that miR-34a intensified LPS-induced lung injury and inflammation by regulating Klf4 and macrophage polarization, which may serve as a potential therapeutic target for acute lung injury/ARDS.

Prenatal BPA and its analogs BPB, BPF, and BPS exposure and reproductive axis function in the male offspring of Sprague Dawley rats

Research in the past has indicated associated long-term and low levels of exposure of bisphenol A (BPA) in early life and neuroendocrine disorders, such as obesity, precocious puberty, diabetes, and hypertension. BPA and its analogs bisphenol B (BPB), bisphenol F (BPF), and bisphenol S (BPS) have been reported to have similar or even more toxic effect as compared to BPA. Exposure of rats to BPA and its analogs BPB, BPF, and BPS resulted in decreased sperm production, testosterone secretion, and histological changes in the reproductive tissues of male rats. In the present study, BPA, BPB, BPF, and BPS were administered in drinking water at concentrations of (5, 25, and 50 μg/L) from pregnancy day (PD) 1 to PD 21. Body weight (BW), hormonal concentrations, antioxidant enzymes, and histological changes were determined in the reproductive tissues. BPA and its analogs prenatal exposure to female rats induced significant statistical difference in the antioxidant enzymes, plasma testosterone, and estrogen concentrations in the male offspring when compared with the control. Histological parameters of both testis and epididymis revealed prominent changes in the reproductive tissues. The present study suggests that BPA and its analogs BPB, BPF, and BPS different concentrations led to marked alterations in the development of the male reproductive system.

Mechanisms of obesity in Prader-Willi syndrome

Obesity is the most common cause of metabolic complications and poor quality of life in Prader-Willi syndrome (PWS). Hyperphagia and obesity develop after an initial phase of poor feeding and failure to thrive. Several mechanisms for the aetiology of obesity in PWS are proposed, which include disruption in hypothalamic pathways of satiety control resulting in hyperphagia, aberration in hormones regulating food intake, reduced energy expenditure because of hypotonia and altered behaviour with features of autism spectrum disorder. Profound muscular hypotonia prevents PWS patients from becoming physically active, causing reduced muscle movements and hence reduced energy expenditure. In a quest for the aetiology of obesity, recent evidence has focused on several appetite-regulating hormones, growth hormone, thyroid hormones and plasma adipocytokines. However, despite advancement in understanding of the genetic basis of PWS, there are contradictory data on the role of satiety hormones in hyperphagia and data regarding dietary intake are limited. Mechanistic studies on the aetiology of obesity and its relationship with disease pathogenesis in PWS are required. . In this review, we focused on the available evidence regarding mechanisms of obesity and potential new areas that could be explored to help unravel obesity pathogenesis in PWS.

Prepartal Energy Intake Alters Blood Polymorphonuclear Leukocyte Transcriptome During the Peripartal Period in Holstein Cows

In the dairy industry, cow health and farmer profits depend on the balance between diet (ie, nutrient composition, daily intake) and metabolism. This is especially true during the transition period, where dramatic physiological changes foster vulnerability to immunosuppression, negative energy balance, and clinical and subclinical disorders. Using an Agilent microarray platform, this study examined changes in the transcriptome of bovine polymorphonuclear leukocytes (PMNLs) due to prepartal dietary intake. Holstein cows were fed a high-straw, control-energy diet (CON; NE_L = 1.34 Mcal/kg) or overfed a moderate-energy diet (OVE; NE_L = 1.62 Mcal/kg) during the dry period. Blood for PMNL isolation and metabolite analysis was collected at −14 and +7 days relative to parturition. At an analysis of variance false discovery rate <0.05, energy intake (OVE vs CON) influenced 1806 genes. Dynamic Impact Approach bioinformatics analysis classified treatment effects on Kyoto Encyclopedia of Genes and Genomes pathways, including activated oxidative phosphorylation and biosynthesis of unsaturated fatty acids and inhibited RNA polymerase, proteasome, and toll-like receptor signaling pathway. This analysis indicates that processes critical for energy metabolism and cellular and immune function were affected with mixed results. However, overall interpretation of the transcriptome data agreed in part with literature documenting a potentially detrimental, chronic activation of PMNL in response to overfeeding. The widespread, transcriptome-level changes captured here confirm the importance of dietary energy adjustments around calving on the immune system.

Molecular and Computational Studies on Apoptotic Pathway Regulator, Bcl-2 Gene from Breast Cancer Cell Line MCF-7

Cancer is a dreadful disease constituting abnormal growth and proliferation of malignant cells in the body. Next to lung cancer, breast cancer is the most common form of cancer affecting women. The apoptotic pathway regulators, B cell lymphoma family of protein, play a key role in various malignancies defining cancer and their constitutive expression plays an integral role in breast cancer chemotherapy. The research work discusses the identification and molecular cloning of a B cell lymphoma like gene from human breast cancer cell line. The open reading frame of the gene consisted of 965 nucleotides, encoding a protein of 380 amino acids with a predicted molecular weight of 42.5 kilodalton. The predicted physiochemical properties of the gene were as follows: Isoelectric point - 9.49, molecular formula - C₁₈₉₃H₃₀₀₄N₅₃₄O₅₄₈S_16, total number of negatively charged residues, (Aspartate+Glutamate) - 26, total number of positively charged residues, (Arginine+Lysine)-39, instability index-42.08 (unstable protein) and grand average of hydropathicity is -0.202. Additionally, phobius prediction suggested non-cytoplasmic localization of the putative protein. The presence of secondary structure in the protein was determined by Memsat program. A 3 dimensional protein homology model was generated using threading based method of protein modeling for structural and functional annotation of the putative protein. Future prospects accounts for the biochemical characterization of the enzyme including in vitro assays on breast cancer cell line would establish the functional characteristics of the protein and its physiological mechanisms in breast cancer development and its therapeutic-target role in future.

Risk Factors of Tendo-Achilles Injury in Football, Cricket and Badminton Players at Dhaka, Bangladesh

Achilles tendon is the tendon connecting the heel with the calf muscles. Tendo-achilles injury (TAI) in players is common in games. The frequency of TAI is unknown and aetiology is controversial: The present descriptive cross-sectional study was done to determine the prevalence of TAI and associated factors contributing to it in football, cricket and badminton. From January to June 2012, male players (n = 131), age -17-35 years, were selected by purposive sampling technique from renowned sporting clubs at Dhaka, Bangladesh. TAI was diagnosed through structured questionnaire and interviewing the respondents. The analysis by Statistical Package for Social Sciences (SPSS) programme revealed that 11.5% players suffered from TAI, i.e. prevalence was 115 per 1000 respondents. Most injuries (70/131; 53.4%) occurred in the playground and (59/131; 45.3%) happened in practice field. Injuries among the players of third division were higher, i.e. about 36% (p = 0.000). TAI was significantly dependent on occupation (p = 0.046), BMI (p = 0.008), divisional status (p = 0.023), game type (p = 0.043), ground condition (p = 0.05) and injury severity (p = 0.000). The injured players referred for treatment to the physiotherapist was highest (9/15, i.e. 60%) followed by the physicians (5/15, i.e. 33%) (p = 0.000). The associations of TAI with various factors were discussed suggesting effective measures be taken and treatment, particularly physiotherapy, be given to injured players. However, there is a need of team work with sports medicine specialist also to enable the injured players to continue their professional games.

Abundance of ruminal bacteria, epithelial gene expression, and systemic biomarkers of metabolism and inflammation are altered during the peripartal period in dairy cows

Seven multiparous Holstein cows with a ruminal fistula were used to investigate the changes in rumen microbiota, gene expression of the ruminal epithelium, and blood biomarkers of metabolism and inflammation during the transition period. Samples of ruminal digesta, biopsies of ruminal epithelium, and blood were obtained during -14 through 28d in milk (DIM). A total of 35 genes associated with metabolism, transport, inflammation, and signaling were evaluated by quantitative reverse transcription-PCR. Among metabolic-related genes, expression of HMGCS2 increased gradually from -14 to a peak at 28 DIM, underscoring its central role in epithelial ketogenesis. The decrease of glucose and the increase of nonesterified fatty acids and β-hydroxybutyrate in the blood after calving confirmed the state of negative energy balance. Similarly, increases in bilirubin and decreases in albumin concentrations after calving were indicative of alterations in liver function and inflammation. Despite those systemic signs, lower postpartal expression of TLR2, TLR4, CD45, and NFKB1 indicated the absence of inflammation within the epithelium. Alternatively, these could reflect an adaptation to react against inducers of the immune system arising in the rumen (e.g., bacterial endotoxins). The downregulation of RXRA, INSR, and RPS6KB1 between -14 and 10 DIM indicated a possible increase in insulin resistance. However, the upregulation of IRS1 during the same time frame could serve to restore sensitivity to insulin of the epithelium as a way to preserve its proliferative capacity. The upregulation of TGFB1 from -14 and 10 DIM coupled with upregulation of both EGFR and EREG from 10 to 28 DIM indicated the existence of 2 waves of epithelial proliferation. However, the downregulation of TGFBR1 from -14 through 28 DIM indicated some degree of cell proliferation arrest. The downregulation of OCLN and TJP1 from -14 to 10 DIM indicated a loss of tight-junction integrity. The gradual upregulation of membrane transporters MCT1 and UTB to peak levels at 28 DIM reflected the higher intake and fermentability of the lactation diet. In addition, those changes in the diet after calving resulted in an increase of butyrate and a decrease of ruminal pH and acetate, which partly explain the increase of Anaerovibrio lipolytica, Prevotella bryantii, and Megasphaera elsdenii and the decrease of fibrolytic bacteria (Fibrobacter succinogenes, Butyrivibrio proteoclasticus). Overall, these multitier changes revealed important features associated with the transition into lactation. Alterations in ruminal epithelium gene expression could be driven by nutrient intake-induced changes in microbes; microbial metabolism; and the systemic metabolic, hormonal, and immune changes. Understanding causes and mechanisms driving the interaction among ruminal bacteria and host immunometabolic responses merits further study.

Inflammation- and lipid metabolism-related gene network expression in visceral and subcutaneous adipose depots of Holstein cows

This experiment was conducted to determine the effects of energy overfeeding on gene expression in mesenteric (MAT), omental (OAT), and subcutaneous (SAT) adipose tissue (AT) from nonpregnant and nonlactating Holstein cows. Eighteen cows were randomly assigned to either a controlled energy [LE, net energy for lactation (NE(L)) = 1.35 Mcal/kg of dry matter (DM)] or moderate energy-overfed group (HE, NE(L) = 1.62 Mcal/kg of DM) for 8 wk. Cows were then euthanized and subsamples of MAT, OAT, and SAT were harvested for transcript profiling via quantitative PCR of 34 genes involved in lipogenesis, triacylglycerol (TAG) synthesis, lactate signaling, hepatokine signaling, lipolysis, transcription regulation, and inflammation. The interaction of dietary energy and adipose depot was not significant for any gene analyzed except LPL, which indicated a consistent response to diet. Expression of ACACA and FASN was greater in SAT than MAT, whereas expression of SCD and ADFP were greatest in SAT, intermediate in OAT, and lowest in MAT. However, the 2 visceral depots had greater expression of THRSP, ACLY, LPL, FABP4, GPAM, and LPIN1 compared with SAT. The transcription factor SREBF1 was more highly expressed in MAT and SAT than in OAT. The expression of PNPLA2 was greater in visceral AT sites than in SAT, but other lipolysis-related genes were not differentially expressed among AT depots. Visceral AT depots had greater expression of LEP, ADIPOQ, and SAA3 compared with SAT. Moreover, MAT had greater expression than SAT of proinflammatory cytokines (IL1B and IL6), IL6 receptor (IL6R), and chemokines (CCL2 and CCL5). However, TNF expression was greatest in SAT, lowest in OAT, and intermediate in MAT. Overall, results indicated that visceral AT might be more active in uptake of preformed long-chain fatty acids than SAT, whereas de novo fatty acid synthesis could make a greater contribution to the intracellular pool of fatty acids in SAT than in visceral AT. The visceral AT compared with SAT seem to have a greater capacity for expression (and potentially for secretion) of proinflammatory cytokines; thus, excessive accumulation of visceral lipid due to a long-term overfeeding energy may be detrimental to liver function and overall health of dairy cows, particularly during the transition period.

Postpartal immunometabolic gene network expression and function in blood neutrophils are altered in response to prepartal energy intake and postpartal intramammary inflammatory challenge

The effect of over-feeding energy prepartum on blood polymorphonuclear neutrophil (PMN) response remains unclear. Cows fed controlled (CON; 1.34Mcal/kg of dry matter) or excess energy (OVE; 1.62Mcal/kg dry matter) during the dry period (~45d before expected calving date) received an intramammary (IM) challenge with Escherichia coli lipopolysaccharide (LPS) during the postpartal period to determine the effects of IM LPS and prepartal diet on the expression of key genes associated with immunometabolic response in blood PMN. Feed intake and daily milk yield were recorded throughout the study period. At 7d in milk (DIM), all cows received LPS (200µg) into 1 rear mammary quarter. Blood PMN were isolated at 7, 14, and 30 DIM, as well as before (0h) and after (12h) IM LPS challenge for gene expression analysis using quantitative real time PCR. Phagocytosis capabilities in vitro were assessed at 7, 14, and 30 DIM. Data were analyzed using the MIXED procedure of SAS with repeated measures. No differences in feed intake and milk yield were observed between OVE- and CON-fed cows. As expected, IM LPS challenge altered the expression of genes associated with the immune response (e.g., 1.9- and 1.8-fold for SELL and TLR2, respectively), metabolism (e.g., 1.8- and -1.8-fold for LDHA and SLC2A1, respectively), and transcription (e.g., 1.1- and 1.7-fold for NCOR1 and PPARD, respectively). At 12h postchallenge, an upregulation of TLR2 (1.8-fold), HIF1A (1.9-fold), and NFKB1 (1.5-fold) was observed for OVE rather than CON. At 7 DIM, S100A9 tended (2.2-fold) to be upregulated for OVE rather than CON. At 14 DIM, OVE resulted in lower PMN phagocytosis and an upregulation of NCOR2 (1.6-fold) and RXRA (1.9-fold) compared with CON-fed cows. At 30 DIM, an upregulation of MPO (3.5-fold) and PLA2G4A (1.5-fold) and a tendency for RXRA (1.7-fold) was observed for OVE- rather than CON-fed cows. Our results suggest that IM LPS challenge altered gene expression associated with metabolism in PMN and that OVE impaired PMN phagocytosis and increased the expression of immunometabolic genes after IM LPS challenge and during the postpartal period. The current study provides new linkages among prepartal feed energy intake, metabolism, and immune response of blood PMN and risk of disease during early lactation.

MicroRNA expression patterns in the bovine mammary gland are affected by stage of lactation

The objective of this work was to determine the expression pattern of microRNA (miR) associated with cellular proliferation, lipid metabolism, and innate immunity in dairy cow mammary gland tissue at different stages of lactation. The expression of miR-10a, miR-15b, miR-16, miR-21, miR-31, miR-33b, miR-145, miR-146b, miR-155, miR-181a, miR-205, miR-221, and miR-223 was studied by real-time reverse-transcription PCR in tissue (n=7/stage) harvested via repeated biopsies during the dry period (-30 d prepartum), the fresh period (7 d postpartum), and early lactation (30 d postpartum). Except for miR-31, all miR studied increased in expression between the dry and fresh periods. Among those upregulated, the expression of miR-221 increased further at early lactation, suggesting a role in the control of endothelial cell proliferation or angiogenesis, whereas the expression of miR-223 decreased at early lactation but to a level that was greater than in the dry period, suggesting it could play a role in the mammary response to pathogens soon after parturition. The expression of miR-31, a hormonally regulated miR that inhibits cyclin gene expression, was greater at early lactation compared with the dry period. From a metabolic standpoint, the consistent upregulation of miR-33b during early lactation compared with the dry period suggests that this miR may exert some control over lipogenesis in mammary tissue. Overall, results indicate that expression of miR associated with transcriptional regulation of genes across diverse biological functions is altered by stage of lactation. The specific roles of these miR during lactation will require further research.

Evaluation of outcomes associated with placement of elective, urgent, and emergency cerclage

OBJECTIVES

The aim of this study was to assess pregnancy outcomes after cervical cerclage.

METHODS

A retrospective analysis of all cervical cerclages placed at Al Qassimi Hospital from 2004 to 2008 was performed. The primary outcome of interest was prolongation of pregnancy beyond 36 wks. Secondary outcomes were premature rupture of membranes, birth weight <1,500 g, and neonatal death.

RESULTS

Cerclage was placed in 145 women: 112 elective, 16 urgent, and 17 emergency groups. Delivery beyond 36 weeks occurred in 79.4, 73.3, and 47.1 % in the elective, urgent, and emergency groups, respectively, p = 0.011. When comparing between elective, urgent, and emergency groups, incidences of low birth weight were 9.8, 13.3, and 33.3 %, respectively, p = 0.06, and premature ruptures of membranes occurred in 7.2, 6.3, and 17.7 %, respectively, p = 0.16. There were five neonatal deaths.

CONCLUSION

Therefore, although cerclage gives best results when it is performed as an elective procedure, emergency cerclage still confers some benefits.

Effect of citric acid, avilamycin, and their combination on the performance, tibia ash, and immune status of broilers

The aim of this study was to determine the effect of the supplementation of an organic acid (citric acid), antibiotic growth promoter (avilamycin), and their combination for a period of 35 d on the growth, feed efficiency, carcass yield, tibia ash, and immune status of broilers. One hundred sixty 1-d-old broiler chicks (Hubbard Classic) were randomly distributed into 4 groups with 4 replicate cages having 10 birds in each. A corn-soybean-based diet was used as the basal diet (control). The basal diet was supplemented with an organic acid (citric acid, 0.5%), an antibiotic growth promoter (avilamycin, 0.001%), and their combination in other groups. The highest BW was attained in citric acid-fed chicks (1,318 g), which was significantly (P < 0.05) higher than control chicks (1,094 g) or avilamycin-fed chicks (1,217 g). The combination-fed chicks showed similar weight (1,246 g) as citric acid- or avilamycin-fed chicks (P > 0.05). Total feed intake was higher in citric acid-fed chicks compared with antibiotic-supplemented chicks. The addition of citric acid improved feed conversion efficiency (g of weight gain/ kg of feed intake) significantly (P < 0.05) compared with control chicks or its combination with avilamycin. Higher carcass weights were found in chicks fed the combination diet. Supplementation of citric acid increased tibia ash percentage significantly (P < 0.05) compared with controls. Addition of citric acid reduced the pH of the formulated diets. An improvement of immune status was detected by densely populated immunocompetent cells in the lamina propria and submucosa of cecal tonsils and ileum and also in the cortex and medulla of bursa follicles in citric acid-supplemented chicks. Supplementation of citric acid at 0.5% in the diet had positive effects on growth, feed intake, feed efficiency, carcass yield, bone ash, and immune status of broilers. Therefore, citric acid might be a useful additive instead of antibiotic growth promoters such as avilamycin, considering performance and health status of broilers.

Effects of kynurenic acid as a glutamate receptor antagonist in the guinea pig

Glutamate excitotoxicity is implicated in both the genesis of neural injury and noise-induced hearing loss (NIHL). Acoustic overstimulation may result in excessive synaptic glutamate, resulting in excessive binding to post-synaptic receptors and the initiation of a destructive cascade of cellular events, thus leading to neuronal degeneration and NIHL. The purpose of this study was to determine whether this apparent excitotoxicity can be attenuated by kynurenic acid (KYNA), a broad-spectrum glutamate receptor antagonist, and protect against noise-induced temporary threshold shifts (TTS). Guinea pigs were randomly assigned to three separate groups. Base-line compound action potentials (CAP) thresholds and cochlear microphonics (CM) were recorded. Group I was treated with physiologic saline as a vehicle control applied to the round window membrane that was followed by 110 dB SPL wide-band noise for 90 min. Group II received 5 mM KYNA followed by noise exposure, and group III received 5 mM KYNA alone without noise exposure. Post-drug and noise levels of CAP thresholds and CM were then obtained. Noise exposure in the control group caused a significant temporary threshold shift (TTS) of 30-40 dB across the frequencies tested (from 3 kHz to 18 kHz). Animals that received 5 mM KYNA prior to noise exposure (group II) showed statistically significant protection against noise-induced damage and demonstrated a minimal TTS ranging between 5 and 10 dB at the same frequencies. Animals in group III receiving KYNA without noise exposure showed no change in thresholds. Additionally, cochlear microphonics showed no considerable difference in threshold shifts when controls were compared to KYNA-treated animals. These results show that antagonizing glutamate receptors can attenuate noise-induced TTS, suggesting that glutamate excitotoxicity may play a role in acoustic trauma.

Biologic activity of mitochondrial metabolites on aging and age-related hearing loss

HYPOTHESIS

Compounds that upregulate mitochondrial function in an aging model will improve hearing and reduce some of the effects of aging.

BACKGROUND

Reactive oxygen metabolites (ROM) are known products of oxidative metabolism and are continuously generated in vivo. More than 100 human clinical conditions have been associated with ROM, including atherosclerosis, arthritis, autoimmune diseases, cancers, heart disease, cerebrovascular accidents, and aging. The ROM are extremely reactive and cause extensive DNA, cellular, and tissue damage. Specific deletions within the mitochondrial DNA (mtDNA) occur with increasing frequency in age and presbyacusis. These deletions are the result of chronic exposure to ROM. When enough mtDNA damage accrues, the cell becomes bioenergetically deficient. This mechanism is the basis of the mitochondrial clock theory of aging, also known as the membrane hypothesis of aging. Nutritional compounds have been identified that enhance mitochondrial function and reverse several age-related processes. It is the purpose of this article to describe the effects of two mitochondrial metabolites, alpha-lipoic acid and acetyl L-carnitine, on the preservation of age-related hearing loss.

METHODS

Twenty-one Fischer rats, aged 24 months, were divided into three groups: acetyl-l-carnitine, alpha-lipoic acid, and control. The subjects were orally supplemented with either a placebo or one of the two nutritional compounds for 6 weeks. Auditory brainstem response testing was used to obtain baseline and posttreatment hearing thresholds. Cochlear, brain, and skeletal muscle tissues were obtained to assess for mtDNA mutations.

RESULTS

The control group demonstrated an expected age-associated threshold deterioration of 3 to 7 dB in the 6-week study. The treated subjects experienced a delay in progression of hearing loss. Acetyl-l-carnitine improved auditory thresholds during the same time period (p<0.05). The mtDNA deletions associated with aging and presbyacusis were reduced in the treated groups in comparison with controls.

CONCLUSIONS

These results indicate that in the proposed decline in mitochondrial function with age, senescence may be delayed by treatment with mitochondrial metabolites. Acetyl-l-carnitine and alpha-lipoic acid reduce age-associated deterioration in auditory sensitivity and improve cochlear function. This effect appears to be related to the mitochondrial metabolite ability to protect and repair age-induced cochlear mtDNA damage, thereby upregulating mitochondrial function and improving energy-producing capabilities.

Sarthran preserves cochlear microcirculation and reduces temporary threshold shifts after noise exposure

The cause of noise-induced hearing loss remains unclear despite years of both epidemiologic and experimental investigation. Among the many possible pathophysiologic mechanisms that may contribute to noise-induced temporary or permanent threshold shifts are insufficiencies in cochlear blood flow. Although the literature is inconsistent, several histologic and physiologic studies demonstrate signs of reduced circulation in the cochlea after noise exposure. Recent studies using computer-enhanced intravital microscopy complement these earlier findings. Evidence suggests that these microcirculatory events are mediated in part by several circulating factors, including the potent vasoactive peptide angiotensin. This study investigated this possibility by pretreating with the angiotensin receptor antagonist sarthran during noise exposure and examining both cochlear microcirculation and auditory sensitivity. The results of these experiments show noise-induced ischemia in the lateral wall of the cochlea and temporary threshold shifts. Treatment with sarthran prevented this noise-induced microcirculatory ischemia and preserved auditory sensitivity at the low frequencies tested. These findings support a role for the angiotensinergic system during noise exposure and suggest that preservation of cochlear blood flow is functionally related to auditory sensitivity.

Mitochondrial DNA deletions associated with aging and presbyacusis

BACKGROUND

The membrane hypothesis of aging proposes an association between reactive oxygen metabolites and aging processes. Reactive oxygen metabolites are a normal by-product of oxidative phosphorylation and are also formed under conditions of ischemia, hypoperfusion, and as a result of environmental contaminants. Among the many detrimental activities of reactive oxygen metabolites, also known as free oxygen radicals, is direct damage to mitochondrial DNA. Progressive accumulation of mitochondrial DNA damage renders cells unable to conduct oxidative phosphorylation reactions effectively, thereby leading to a bioenergetically deficient cell. Over time, mitochondrial DNA damage accumulates and leads to cellular dysfunction with subsequent organ failure, aging, and ultimately, death. This sequence forms the basis of the membrane hypothesis of aging.

OBJECTIVE

To determine if the membrane hypothesis of aging may be involved in the development of presbyacusis.

DESIGN

Fischer rats from 4 age groups were tested for auditory sensitivity using the auditory brainstem response. Brain, stria vascularis, and auditory nerve tissues were harvested and mitochondrial DNA was amplified to identify the highly conserved cytochrome b and ND1-16S ribosomal RNA segment of the NADH genes, as well as a 4834-base pair (bp) deletion associated with aging.

SUBJECTS

Fischer rats (n=28) from 4 age groups were used: young (2-4 months [n=9]), mid-young (9-11 months [n=5]), mid-old (18-20 months [n=5]), and old (30-34 months [n=9]).

RESULTS

The results demonstrate a progressive reduction in auditory sensitivity with age. The mitochondrial DNA studies identify a significant increase in the presence of the 4834-bp deletion in the aged subjects compared with the young.

CONCLUSIONS

These findings raise the possibility that the 4834-bp deletion may be associated with presbyacusis, as well as with aging.

Age-related differences in cochlear microcirculation and auditory brain stem response

OBJECTIVE

To examine possible age-related differences in auditory sensitivity and cochlear vascular properties.

DESIGN

This study is designed to provide information regarding cochlear function using physiological and audiological measures. Each animal underwent intravital microscopic evaluation of red blood cell velocity, vessel diameter, and vascular permeability in the second turn of the cochlear lateral wall. Auditory brain stem responses were used to determine hearing sensitivity.

SUBJECTS

Four age ranges of male Fischer rats were studied: young, 2 to 4 months (n = 9); mid-young, 9 to 11 months (n = 8); mid-old, 18 to 20 months (n = 6); and old, 30 to 34 months (n = 10).

RESULTS

Auditory brain stem response testing showed an age-related decrease in auditory sensitivity. Intravital microscopic analysis showed age-related statistically significant decreases in red blood cell velocity and increased vascular permeability with a trend for reduced capillary diameters.

CONCLUSIONS

The process of aging is associated with many biochemical and physiological changes that include decrease in cellular water concentration, ionic changes, and decreased elasticity of cellular membranes. One contributing factor to this process may be altered vascular characteristics, such as reduced flow and vascular plasticity, as well as increased vascular permeability. These age-related changes may result in reductions in oxygen and nutrient delivery, and also waste elimination. Our results suggest that progressive age-associated vascular compromise may be a contributing factor in presbycusis.

In vitro mineral binding capacity of three fiber sources for Ca, Mg, Cu and Zn by two different methods

Acid-washing centrifugation (AWC) and cold-hot-water-enzyme incubation (WEI) methods were used to study the binding capacity (BC) of wheat bran, rice bran, and oat fiber for calcium, magnesium, copper, and zinc. Treated fibers were analyzed for protein, phytic acid (PA), total dietary fiber (TDF), and minerals. Protein content was significantly (P < 0.05) lower in WEI fibers than AWC fibers. WEI fibers had low protein concentration and no PA but higher TDF values (P < 0.05). Levels of Mg were the highest among the minerals studied. AWC treatment was significantly (P < 0.05) more efficient in stripping minerals than the WEI treatment. AWC fibers bound more minerals. Results indicate that the BC values of the fibers for minerals by the two methods were not comparable.

Association of mitochondrial DNA deletions and cochlear pathology: a molecular biologic tool

The purpose of these experiments was to develop a method of isolation, amplification, and identification of cochlear mitochondrial DNA (mtDNA) from minute quantities of tissue. Additionally, studies were designed to detect mtDNA deletions (mtDNA del) from the cochlea that previously have been amplified from other organ systems and tissues. MtDNA del have been associated with many pathologies, including neurological disorders, sensorineural hearing loss, ischemia, cardiomyopathies, and aging. DNA was extracted from rat and human tissues, and polymerase chain reaction was used to amplify mtDNA sequences. A 360 base pair (bp) cytochrome-b gene product and the highly conserved ND1-16S ribosomal ribonucleic acid regions found only in mtDNA were amplified from all tissues. Preliminary studies have identified a 4834 bp mtDNA del in aged rats and a corresponding 4977 bp mtDNA del in aged humans. Additionally, preliminary results in human archival temporal bone studies reveal the presence of the 4977-bp mtDNA deletion in two out of three patients with presbycusis. The deletion was not evident in age-matched control patients without a history of presbycusis. This technique of mtDNA identification makes it possible to investigate specific mtDNA defects from a single cochlea, promoting the study of hereditary hearing loss and presbycusis at a molecular biologic level.

Anesthetic considerations for parturients with primary pulmonary hypertension: review of the literature and clinical presentation

Primary pulmonary hypertension, though uncommon, is found relatively frequently in women of childbearing age and carries a high peripartum mortality. We present a patient with severe primary pulmonary hypertension who underwent two cesarean sections 3 and 6 years after the diagnosis of primary pulmonary hypertension was made. Epidural anesthesia was provided on both occasions and resulted in a good maternal and fetal outcome. We have reviewed the literature as it relates to the choice of anesthetic technique and maternal outcome in patients with primary pulmonary hypertension.

Regional changes in cerebral haemodynamics as a result of a visual stimulus measured by near infrared spectroscopy

Near infrared spectroscopy (NIRS) is used to measure global changes in cerebral haemodynamics. We have adapted the technique to measure regional changes in response to a visual stimulus. Ten volunteers were exposed to a computer generated visual stimulus designed to activate a large area of the visual cortex, including V1, V2, V3, V4 and V5. The stimulus was on for 30 s and off for 30 s. Changes in the concentrations of oxyhaemoglobin ([HbO2]) and deoxyhaemoglobin ([Hb]) were measured using a commercial spectrometer (NIRO500), over the occipital cortex. The data were summed over ten cycles. As a control, the experiment was repeated over the frontal cortex. For each subject [HbO2] increased during stimulation, and decreased when the stimulus was off. The mean (+/- s.e.m.) change in [HbO2] was 0.54 +/0 0.14 micromol 1(-1). The change in total haemoglobin concentration, given by [HbO2] + [Hb] was 0.61 +/- 0.21 micromol 1(-1), equivalent to a rise in cerebral blood volume of 0.04 +/- 0.01 ml 100 g(-1) which is about 2% of the total cerebral blood volume. There was no significant change in [HbO2] over the frontal cortex, implying that the changes in blood volume originated in the occipital lobe. This demonstrates that NIRS provides a non-invasive method of measuring regional changes in cerebral haemodynamics as a result of visual stimulation.

Feeding Strategy For Improving Dairy Cattle Productivity In Small Holder Farm In Bangladesh

Dairy animal rearing is an inseparable and integrated part of smallholder subsistence farming system. Dairy cattle production in the country is characterized by low productivity levels due mainly to genetic and nutritional constraints. Unless feeding management is improved these animals may be limited to fully express their potential genetic superiority. It is fundamental approach to provide good quality diets to dairy cattle in sufficient amount to maximize production. Dairying provides women with a regular daily income vital to household good security and family well being. Quantitative and qualitative shortage of feeds and fodder affects the performance of milking animal. Local cows yield on average 1.5 Lit. milk per day against 5-8 Lit. in cross bred cows, require better feeding mainly concentrates, which is not available to the farmers at the affordable prices. But income of farmers can be increased up to two fold (Tk.58 vs 115) by rearing cross bred cows. Since feed cost is becoming the most important factor in livestock production, increasing self sufficiency in feed production will be an important factor in future development programs. DOI: http://dx.doi.org/10.3329/bjas.v38i1-2.9914 BJAS 2009; 38(1-2): 67-85