Reorganization of the Flagellum Scaffolding Induces a Sperm Standstill During Fertilization

Mammalian sperm delve into the female reproductive tract to fertilize the female gamete. The available information about how sperm regulate their motility during the final journey to the fertilization site is extremely limited. In this work, we investigated the structural and functional changes in the sperm flagellum after acrosomal exocytosis and during the interaction with the eggs. The evidence demonstrates that the double helix actin network surrounding the mitochondrial sheath of the midpiece undergoes structural changes prior to the motility cessation. This structural modification is accompanied by a decrease in diameter of the midpiece and is driven by intracellular calcium changes that occur concomitant with a reorganization of the actin helicoidal cortex. Although midpiece contraction may occur in a subset of cells that undergo acrosomal exocytosis, live-cell imaging during in vitro fertilization showed that the midpiece contraction is required for motility cessation after fusion is initiated. These findings provide the first evidence of the F-actin network's role in regulating sperm motility, adapting its function to meet specific cellular requirements during fertilization, and highlighting the broader significance of understanding sperm motility.

Significant statement

In this work, we demonstrate that the helical structure of polymerized actin in the flagellum undergoes a rearrangement at the time of sperm-egg fusion. This process is driven by intracellular calcium and promotes a decrease in the sperm midpiece diameter as well as the arrest in motility, which is observed after the fusion process is initiated.

Structured Illumination Microscopy Improves Spot Detection Performance in Spatial Transcriptomics

Spatial biology is a rapidly growing research field that focuses on the transcriptomic or proteomic profiling of single cells within tissues with preserved spatial information. Imaging-based spatial transcriptomics uses epifluorescence microscopy, which has shown remarkable results for the identification of multiple targets in situ. Nonetheless, the number of genes that can be reliably visualized is limited by the diffraction of light. Here, we investigate the effect of structured illumination (SIM), a super-resolution microscopy approach, on the performance of single-gene transcript detection in spatial transcriptomics experiments. We performed direct mRNA-targeted hybridization in situ sequencing for multiple genes in mouse coronal brain tissue sections. We evaluated spot detection performance in widefield and confocal images versus those with SIM in combination with 20×, 25× and 60× objectives. In general, SIM increases the detection efficiency of gene transcript spots compared to widefield and confocal modes. For each case, the specific fold increase in localizations is dependent on gene transcript density and the numerical aperture of the objective used, which has been shown to play an important role, especially for densely clustered spots. Taken together, our results suggest that SIM has the capacity to improve spot detection and overall data quality in spatial transcriptomics.

Extending resolution within a single imaging frame

The resolution of fluorescence microscopy images is limited by the physical properties of light. In the last decade, numerous super-resolution microscopy (SRM) approaches have been proposed to deal with such hindrance. Here we present Mean-Shift Super Resolution (MSSR), a new SRM algorithm based on the Mean Shift theory, which extends spatial resolution of single fluorescence images beyond the diffraction limit of light. MSSR works on low and high fluorophore densities, is not limited by the architecture of the optical setup and is applicable to single images as well as temporal series. The theoretical limit of spatial resolution, based on optimized real-world imaging conditions and analysis of temporal image stacks, has been measured to be 40 nm. Furthermore, MSSR has denoising capabilities that outperform other SRM approaches. Along with its wide accessibility, MSSR is a powerful, flexible, and generic tool for multidimensional and live cell imaging applications.

Fluorescence fluctuation based super resolution microscopy, basic concepts for an easy start

Due to the wave nature of light, optical microscopy has a lower-bound lateral resolution limit of approximately half of the wavelength of visible light, i.e., within the range of 200 to 350 nm. Fluorescence Fluctuation based Super Resolution Microscopy (FF-SRM) is a term used to encompass a collection of image analysis techniques which rely on the statistical processing of temporal variations of the fluorescence signal. FF-SRM aims to reduce the uncertainty of the location of fluorophores within an image, often improving spatial resolution to several tens of nanometers. FF-SRM is suitable for live-cell imaging due to its compatibility with most fluorescent probes and relatively simple instrumental and experimental requirements, which are mostly camera-based epifluorescence instruments. Each FF-SRM approach has strengths and weaknesses, which depend directly on the underlying statistical principles through which enhanced spatial resolution is achieved. In this review, the basic concepts and principles behind a range of FF-SRM methods published to date are described. Their operational parameters are explained and guidance for its selection is provided. This article is protected by copyright. All rights reserved.

Capability of Far-Infrared for the selective identification of red and black pigments in paint layers

Artworks are complex objects that merit study and preservation. Far-infrared spectroscopy in ATR mode appears to be a suitable technique for this purpose because it enables information to be obtained regarding the material's composition in a non-destructive way. The use of Far-infrared is especially interesting because most organic compounds do not absorb in this energy range, suggesting the possibility of identifying inorganic pigments. Based on works performed by two research groups from the University of Bologna and the University of Tartu, this study attempts to obtain additional information regarding the capabilities and limitations of Far-infrared spectroscopy when it is applied to objects as complex as artworks. This article first studies the capability of the technique for identifying pigments by following the stability of the position of their absorption bands when mixed with linseed oil, the minimum amount of pigment necessary to be detected and how this amount changes when it is part of a paint layer. The consequences of the pigment: linseed oil interaction and the ageing process are also studied through changes in the linseed oil signal absorptions related to the acid carboxylic and carboxylate bands. The entire study leads to the conclusion that Far-Infrared in ATR mode is an interesting option for the selective identification of some inorganic pigments, but their potential application depends on each case considered.

FCSlib: an open-source tool for fluorescence fluctuation spectroscopy analysis for mobility, number and molecular brightness in R

SUMMARY

FCSlib is an open-source R tool for fluorescence fluctuation spectroscopy data analysis. It encompasses techniques such as Fluorescence Correlation Spectroscopy, Number and Brightness, Pair Correlation Function and Pair Correlation of Molecular Brightness.

AVAILABILITY AND IMPLEMENTATION

Source code available at https://cran.r-project.org/web/packages/FCSlib/ for Linux, Windows and macOS platforms. Sample data as well as a user's guide are available at https://github.com/FCSlib/FCSlib.

SUPPLEMENTARY INFORMATION

Supplementary data are available at Bioinformatics online.

Dielectric spectroscopy of novel bio-based aliphatic-aromatic block copolymers: Poly(butylene terephthalate)-b-poly(lactic acid)

Broadband dielectric spectroscopy has been used to characterize in deep the relaxation behavior of novel bio-based aliphatic-aromatic block copolymers based on poly(butylene terephthalate) (PBT) and poly(lactic acid) (PLA). The results indicate that the copolymerization decreases the ability to crystallize of the resulting block copolymer. The [Formula: see text] relaxation of the block copolymers is consistent with this fact exhibiting initially the characteristics features of an amorphous polymeric material cold crystallizing upon heating. The cold crystallization can be easily visualized by dielectric spectroscopy by a discontinuous and abrupt change of the shape parameters of the [Formula: see text] relaxation. The sub-glass dynamics of the block copolymers is complex and be ascribed to a [Formula: see text] relaxation composed of two local modes, [Formula: see text] and [Formula: see text], which can be assigned to the relaxation in PBT of the bond between the ester oxygen and the aliphatic carbon and to the bond between the aromatic ring carbon to the ester carbon, respectively. With increasing amount of the PLA block the crystallinity decreases as well as the activation energy of the [Formula: see text] mode approaching the expected value for amorphous PBT. On the contrary, the activation energy for the [Formula: see text] exhibits an unexpected increase as the amount of PLA increases. This effect has been explained by considering that at lower temperatures the [Formula: see text] mode of PBT is the more significant while at higher temperatures the [Formula: see text] relaxation of the PLA block becomes the dominant one.

Effect of chemical structure on the subglass relaxation dynamics of biobased polyesters as revealed by dielectric spectroscopy: 2,5-furandicarboxylic acid vs. trans-1,4-cyclohexanedicarboxylic acid

The chemical structure-dynamics relationship for poly(trimethylene 2,5-furanoate) and poly(trimethylene 1,4-cyclohexanedicarboxylate) was investigated via dielectric spectroscopy and compared with that of poly(trimethylene terephthalate) in order to evaluate the impact on the subglass dynamics of the chemical nature of the ring. Further comparison was accomplished with the neopentyl glycol containing counterparts: poly(neopentyl 2,5-furanoate) and poly(neopentyl 1,4-cyclohexanedicarboxylate). Our study reveals a multimodal nature of the subglass β process. For the more flexible polymers (containing cyclohexane rings) three modes for the β process were detected. The faster mode was assigned to the relaxation of the oxygen linked to the aliphatic carbon, the slower one to the link between the aliphatic ring and the ester group, and the third mode to the aliphatic ring. For stiffer polymers (containing aromatic rings), the local modes appear more coupled. This effect is more evident in the polymers with the furan ring where essentially a single β mode can be resolved.

Angiotensin type 1a receptors on corticotropin-releasing factor neurons contribute to the expression of conditioned fear

Although generally associated with cardiovascular regulation, angiotensin II receptor type 1a (AT1a R) blockade in mouse models and humans has also been associated with enhanced fear extinction and decreased post-traumatic stress disorder (PTSD) symptom severity, respectively. The mechanisms mediating these effects remain unknown, but may involve alterations in the activities of corticotropin-releasing factor (CRF)-expressing cells, which are known to be involved in fear regulation. To test the hypothesis that AT1a R signaling in CRFergic neurons is involved in conditioned fear expression, we generated and characterized a conditional knockout mouse strain with a deletion of the AT1a R gene from its CRF-releasing cells (CRF-AT1a R((-/-)) ). These mice exhibit normal baseline heart rate, blood pressure, anxiety and locomotion, and freeze at normal levels during acquisition of auditory fear conditioning. However, CRF-AT1a R((-/-)) mice exhibit less freezing than wild-type mice during tests of conditioned fear expression-an effect that may be caused by a decrease in the consolidation of fear memory. These results suggest that central AT1a R activity in CRF-expressing cells plays a role in the expression of conditioned fear, and identify CRFergic cells as a population on which AT1 R antagonists may act to modulate fear extinction.

Changes in visceral flow induced by laparoscopic and open living-donor nephrectomy: experimental model

Increased intra-abdominal pressure during laparoscopy changes visceral flow. The objective of the present study was to analyze the changes in peripheral and intra-abdominal flow induced by laparoscopic living-donor nephrectomy in an experimental model. Twenty pigs underwent left-sided nephrectomy, 10 at laparoscopy and 10 in an open approach. Renal blood flow (RBF), hepatic arterial flow (HAF), portal flow (PF), and carotid flow (CF) were measured using an electromagnetic probe placed around these vessels. Comparative analysis between the groups demonstrated increased CF (mean [SD], 125.73 [41.69] vs 291.70 [51.52] mL/min; P < .001) and decreased PF (973.67 [131.70] vs 546.83 [217.53] mL/min; P = .001) and HAF (278.00 [94.71] vs 133.33 [112.32] mL/min; P = .03) in pigs that underwent laparoscopy compared with those who underwent open surgery; no significant differences were observed in RBF. In conclusion, laparoscopic nephrectomy induces increased CF and decreased total hepatic flow, at the expense of PF and HAF. With adequate intravascular volume expansion, no differences were observed in RBF between the laparoscopic and open approaches.

Liver expression of matrix metalloproteases and their inhibitors in hepatocellular carcinoma

BACKGROUND

Several studies have suggested the significance of some metalloproteases in the malignant behaviour of hepatocellular carcinoma.

AIMS

To evaluate the liver expression of MMPs and their tissular inhibitors in patients with HCC.

METHODS

An immunohistochemical study using tissue microarrays on samples obtained from 30 HCC patients, with antibodies against MMPs (1, 2, 7, 9, 11, 13 and 14) and TIMPs (1, 2 and 3) was performed. Results were correlated with various clinico-pathological findings and with overall survival.

RESULTS

MMP-1 is mainly expressed by stromal cells, and MMP-13, TIMP-1 and TIMP-2 by inflammatory cells. A positive correlation between MMP-1 expression and larger size tumours (p<0.01) was found. Increased TIMP-2 expression was associated with higher preoperative serum levels of alpha-fetoprotein (p<0.01). Unsupervised hierarchical clustering for total score values designated two groups, one of them characterised by high MMPs and TIMPs expressions, including 21 cases (70%) for tumour cell clustering, 5 cases for fibroblasts (16.6%) and 6 cases for inflammatory cells (20%). All patients showing elevated MMPs and TIMPs expression in stromal cells presented a poor prognosis (p<0.05).

CONCLUSIONS

High liver MMPs and TIMPs expressions in peritumour stromal cells are related to a poorer prognosis in HCC.

Immunohumoral response during laparoscopic and open living donor nephrectomy: an experimental model

Measurement of interleukins (IL) and C-reactive protein (CRP) have demonstrated that a laparoscopic approach may induce less surgical stress than an open approach. The potential influence of this observation in living donor nephrectomy has scarcely been analyzed. The aim of the study was to analyze the immunohumoral response induced by laparoscopic versus open donor nephrectomy in an experimental model. Twenty pigs underwent left nephrectomy, 10 by laparoscopy and 10 by an open approach. In both groups the following parameters were measured: CRP, IL-2, IL-10, tumour necrosis factor alpha (TNF alpha), and endothelin-1 (ET-1). The determinations were done at different times: basal, immediately as well as on the first, third, fifth, and seventh days after the procedure. A comparative analysis between groups demonstrated a significant increases among the open group in the following markers: CRP (1.44 +/- 0.88 vs 1.32 +/- 0.14 mg/dL, P = .046); TNF alpha (131.14 +/- 41.37 vs 57.19 +/- 23.71 pg/mL; P > .001); and ET-1 (0.91 +/- 0.49 vs 0.56 +/- 0.5 fmol/mL; P = .001). The laparoscopic group showed higher levels of IL-2 than the open group. In conclusion, open donor nephrectomy produced a greater immunohumoral response than a laparoscopic approach. The influence of these observations on ischemia-reperfusion injury or on immediate graft function after kidney transplantation has not been clearly established.

Comparative Analysis of the Hemodynamic and Respiratory Parameters During Laparoscopic Versus Open Living Donor Nephrectomy: An Experimental Model

Increased intrabdominal pressure induced by pneumoperitoneum induces modifications in cardiovascular and respiratory systems. The aim of the study was to analyze the hemodynamic and respiratory modifications produced by pneumoperitoneum during living donor nephrectomy in a porcine experimental model. Twenty pigs underwent left nephrectomy, 10 by laparoscopy and 10 by an open approach. The following parameters were measured: mean arterial pressure (MAP), central venous pressure, cardiac output (CO), systemic vascular resistance (SVR), end tidal CO2 (ETCO2), minute volume (MV), respiratory airway pressure (RAP), and "compliance." Both groups were monitored for cardiac and respiratory systems at basal, 5, 30, and 60 minutes as well as postsurgery. The comparative analysis demonstrated increased CO with a higher difference at 30 minutes (4.33 +/- 0.73 vs 8.54 +/- 1.26 L/min, P < .001); decreased SVR (1118.81 +/- 302.52 vs 663.37 +/- 81.45 dinas x s x cm(-5), P < .001), and elevated MAP among the laparoscopic group (66.5 +/- 11.52 vs 80.25 +/- 2.49 mm Hg, P = .004). Analysis of respiratory modifications showed an initial increase in ETCO2 (44.3 +/- 2.6 vs 54.1 +/- 12.56 mm Hg, P < .035) and a higher MV administered (5.6 +/- 0.1 vs 7.01 +/- 0.96 L/min, P = .03) to the laparoscopy group. An increased RAP was observed at 5 minutes (22.11 +/- 2.76 vs 28.8 +/- 3.68 mm Hg, P < .001), in the laparoscopic group and lower levels of "compliance" at the same moment in that group (16 +/- 1.66 vs 14.9 +/- 4.07 cm H2O). Laparoscopic nephrectomy caused an increase in CO and MAP and decreased SVR. Likewise there were elevations of RAP, ETCO2, and MV and a slight decrease in the "compliance."

Liver expression of steroid hormones and Apolipoprotein D receptors in hepatocellular carcinoma

AIM: To evaluate the tissular expression of Androgen (A), Estrogen (E) and Progesterone (Pg) receptors, and Apolipoprotein D (ApoD), in liver tumors from resected hepatocellular carcinoma (HCC) cases in order to assess their possible relationship to prognosis.

METHODS: We performed an immunohistochemical study using tissue microarrays (containing more than 260 cancer specimens, from 31 HCC patients and controls) to determine the presence of specific antibodies against AR, ER, PgR and ApoD, correlating their findings with several clinico-pathological and biological variables. The staining results were categorized using a semi-quantitive score based on their intensity, and the percentage of immunostained cells was measured.

RESULTS: A total of 21 liver tumors (67.7%) were positive for AR; 16 (51.6%) for ER; 26 (83.9%) for PgR and 12 (38.7%) stained for ApoD. We have found a wide variability in the immunostaining score values for each protein, with a median (range) of 11.5 (11.5-229.5) for AR; 11.1 (8.5-65) for ER; 14.2 (4-61) for PgR; and 37.7 (13.8-81.1) for ApoD. A history of heavy ethanol consumption, correlated positively with AR and PgR and negatively with ER status. HCV chronic infection also correlated positively with AR and PgR status. However, the presence of ApoD immunostaining did not correlate with any of these variables. Tumors with a positive immuno-staining for PgR showed a better prognosis.

CONCLUSION: Our results indicate a moderate clinical value of the steroid receptor status in HCC, emphasizing the need to perform further studies in order to evaluate the possible role of new hormonal-based therapies.

Nutritional control, gene regulation, and transformation of vascular smooth muscle cells in atherosclerosis

Contractile-state smooth muscle cells (SMC), the only cell type in the arterial media, undergoes migration to the intima, proliferation, and abundant extracellular matrix production during the early stages of atherosclerosis. This involves the ingestion of low-density lipoprotein (LDL) and modified or oxidised LDL by macrophages together with SMC by several pathways including a scavenger pathway leading to accumulation of cholesterol esters and formation of foam cells. High-plasma cholesterol levels constitute a major causative risk for atherosclerosis. The membrane-bound transcription factor called sterol regulatory element binding protein (SREBP) activates gene-encoding enzymes of cholesterol and fatty acid biosynthesis. The SREBP expression, in response to diet, shows that are involved in both lipogenesis and cholesterol homeostasis, moreover SREBPs are regulated directly by cholesterol. Animal models were used in trials of atherosclerosis, and cholesterol feeding has been described elsewhere as producing atherosclerotic lesions. We have examined the morphological, molecular and proliferative change in arterial SMC mimicking such a cholesterol diet, this transformed SMC is a good model to study the alterations of the differentiated state of SMC, and the transformation into foam cell, caused by cholesterol-rich diet. Despite the complexity of the interactions in atherosclerosis, there are many opportunities to affect the homeostatic balance of the artery wall at SMC levels. We have considered here some of the possible targets for intervention with promising strategies for the nutritional control of the genes, and, in a general way, the possibilities for modulating the expression of genes influencing atherosclerosis.

Modifications of Renal Blood Flow and Serum Interleukin Levels Induced by Laparoscopic and Open Living Donor Nephrectomies For Kidney Transplant: An Experimental Study in Pigs

The increase of intraabdominal pressure (IAP) during laparoscopy modifies renal blood flow (RBF). However, laparoscopic techniques are less invasive than open procedures. The use of interleukins (IL) to evaluate operative trauma of different surgical techniques is controversial. The aim of the study was to analyze the, modifications induced by laparoscopic and open nephrectomies on RBF, renal function and IL levels. Thirty pigs underwent left nephrectomy, 15 by laparoscopy and 15 by an open approach in an experimental autotransplant model. A significant reduction in RBF was observed among the laparoscopic (80 +/- 27 mL/min) versus the open group (263 +/- 3 mL/min, P < .05). Laparoscopy reduced glomerular filtration (GF) (37.6 +/- 1.1%) to a greater extent than an open technique (80.5 +/- 0.4%; P < .05). Serum levels of IL-2, IL-6, IL-10, and tumor necrosis factor (TNF) were lower during laparoscopic than open nephrectomy: 6.8 +/- 0.6 versus 13 .9 +/- 1.1 pg/mL for IL-2, 46.2 +/- 2.3 versus 84.4 +/- 2.5 pg/mL for IL-6, 26.1 +/- 2.4 versus 92.8 +/- 12.6 pg/mL for IL-10, and 17.6 +/- 2.1 versus 38.5 +/- 4.8 pg/mL for TNF (P <.001). In conclusion, laparoscopic nephrectomy for living donor kidney transplant induced significant reductions in RBF and GF. However, there was less increase in IL levels during laparoscopic than the open approach. The influence of these circumstances on graft function after kidney transplantation is not clearly established.

Children's meal patterns have changed over a 21-year period: the Bogalusa Heart Study

OBJECTIVE

The objective of this study was to analyze children's meal patterns over 2 decades.

DESIGN

One 24-hour dietary recall was collected on each child who participated in one of seven cross-sectional surveys.

SUBJECTS/SETTING

Dietary intake data were collected on 1,584 10-year-old children (65% white, 35% African American), in Bogalusa, LA, from 1973 to 1994.

STATISTICAL ANALYSES

Descriptive statistics and one-way analysis of variance adjusting for gender and ethnicity.

RESULTS

From 1973 to 1978, there was a marked increase (P<.0001) in the percentage of children who skipped breakfast, from 8.2% to 29.6%. When school breakfast was introduced in 1981, the proportion of children skipping breakfast declined to 12.5% (P<.01). From 1973-1974 to 1993-1994, the percentage of children eating a school lunch declined from 89.7% (1973-1974) to 78.2% (1993-1994) (P<.001); eating lunch brought from home increased from 5.9% to 11.1% (P<.01); consuming a home dinner decreased from 89.2% to 75.9% (P<.01); eating a dinner prepared outside the home increased from 5.4% to 19.0% (P<.01); consuming a meal at a restaurant increased from 0.3% to 5.4% (P<.0001); consuming snacks decreased (P<.0001); total eating episodes decreased from 6.6 to 5.2 (P<.0001); and eating time span significantly decreased from 12.4 hours to 11.5 hours (P<.0001). Despite these changes in meal patterns, no associations were found between meal patterns and overweight status.

CONCLUSIONS

Striking alterations in the meal patterns of children occurred over the 2-decade period. These changes may have implications for the changes in the dietary intakes of children during the same time. However, data from this study do not support an association between meal patterns and children's overweight status. Further research with multiple days of assessment is needed to better understand the complexity of diet as it relates to childhood obesity.

Presence of bacterial infection in bleeding cirrhotic patients is independently associated with early mortality and failure to control bleeding

Bacterial infection is strongly associated with gastrointestinal bleeding in cirrhotic patients and seems to be related with the failure to control bleeding. The aims of this study were to assess the influence of infections on the failure to control bleeding and death in cirrhotic patients without antibiotic prophylaxis. Ninety-one consecutive bleeding cirrhotic patients were analyzed. Bleeding was managed using somatostatin with sclerotherapy for active bleeding. Screening for bacterial infection (analysis and culture of blood, urine, ascitic and other fluids, together with chest radiography) was made at time 0 and when clinical signs suggested infection. The cause of bleeding was variceal in 72 (79%) patients. Failure to control bleeding occurred in 24 (26%) patients, and 10 (11%) of the patients died. Compared with the group without infection, failure to control bleeding (65% vs 15%; P < 0.001) and mortality (40% vs 3%; P < 0.001), were observed more frequently in patients with infection. Multivariate analysis showed that bacterial infection (OR = 9.7; P < 0.001) and the presence of shock (OR = 3.5; P < 0.05) were independently associated with failure to control bleeding. Bacterial infection (OR = 12.6; P < 0.01), encephalopathy (OR = 6.9; P < 0.05), and shock (OR = 5.8; P < 0.05) were identified as predictive of death. In conclusion, in bleeding cirrhotic patients bacterial infection is associated with failure to control bleeding as well as mortality.

The reversal of the inhibition on lipids synthesis by L-659,699 in arterial smooth muscle cells cultures

The beta-lactone isolated from Fusarium sp. termed L-659,699 is a potent specific inhibitor of the enzyme 3-hydroxi-3-methylglutaril coenzyme A (HMG-CoA) synthase. In cultures of smooth muscle cells (SMC) isolated from aortic-arch of control (C-SMC) and 5% of cholesterol diet (Ch-SMC) treated chicks, the incorporation of (14C)-acetate to lipids (cholesterol, triacylglycerides and cholesterol ester) were greater in Ch-SMC cultures than in C-SMC and the presence of 0.05 microM L-659,699 for 2 h in the incubation medium decrease the synthesis of cholesterol however the triacylglycerides synthesis increase. The effect of inhibitor is stronger in young cultures (3-4 steps) than in the older ones (11-12 steps). In young C-SMC and Ch-SMC cultures the inhibition of cholesterol and triacylglycerides synthesis by L-659,699 was reversal.

Antipyrine clearance and metabolite formation in primary biliary cirrhosis

The disposition of antipyrine is altered and may be a prognostic factor in the presence of various types of hepatic dysfunction. The object of the present study was to investigate whether antipyrine clearance and metabolite formation are useful to detect altered metabolic function in primary biliary cirrhosis. Saliva clearance of antipyrine and the formation clearance of antipyrine metabolites (hydroxymethylantipyrine, HMA; norantipyrine, NORA; and 4-hydroxyantipyrine, OHA) were investigated in a group of 34 women with biopsy-proven PBC (mean age 60 years; range 39-87 years) and in 15 healthy control women (mean age 62 years; range 46-78 years). Parameters of antipyrine clearance of patients in stage I and II were similar to those observed in healthy subjects. When compared to patients in stage I, patients in advanced stages showed a reduction in antipyrine clearance (-29% and -44% in stages III and IV, respectively) and increases in antipyrine half-life (+24% and +75% in stages III and IV, respectively). The reduction in antipyrine clearance was due to a reduction in the formation of all three antipyrine metabolites, with the formation clearance of both HMA and NORA decreasing to a slightly greater extent than that of OHA. Antipyrine clearance correlated significantly with serum bilirubin (P < 0.017) and the Mayo risk score (P < 0.001). Logistic regression analysis indicated that antipyrine clearance was an independent predictor of the histological stage of the disease (P < 0.001). Antipyrine clearance and metabolite formation is a sensitive parameter for assessing hepatic metabolic function in primary biliary cirrhosis.

Metabolism of palmitic and docosahexaenoic acids in Reuber H35 hepatoma cells

In this work, we have modified the fatty acid composition of Reuber H35 hepatoma cells by supplementation of the culture medium with a saturated (palmitic) or a polyunsaturated (docosahexaenoic) acid. These fatty acids were incorporated into total lipids and phospholipids of hepatoma cells. Palmitic acid readily increased the percentage of its monounsaturated derivative (16:1 n-7). When both fatty acids were supplemented at the same concentration, the percentage of docosahexaenoic acid in the total lipids and phospholipids of Reuber H35 cells increased more than that of palmitic acid. Although the levels of 16:0 increased, the addition of docosahexaenoic acid to the culture medium decreased the percentages of monoenoic acids. From our results, it can be concluded that palmitic and docosahexaenoic acids modify the fatty acid composition of Reuber H35 hepatoma cells. The profound changes induced by docosahexaenoic acid, especially those in the phospholipid fraction, may be of great interest given the main role of these components in the regulation of chemical and physical properties of biological membranes and/or membrane systems.

Impact of community intervention to reduce patient delay time on use of reperfusion therapy for acute myocardial infarction: rapid early action for coronary treatment (REACT) trial. REACT Study Group

BACKGROUND

Reperfusion therapy for acute myocardial infarction (AMI) is a time-dependent intervention that can reduce infarct-related morbidity and mortality. Out-of-hospital patient delay from symptom onset until emergency department (ED) presentation may reduce the expected benefit of reperfusion therapy.

OBJECTIVE

To determine the impact of a community educational intervention to reduce patient delay time on the use of reperfusion therapy for AMI.

METHODS

This was a randomized, controlled community-based trial to enhance patient recognition of AMI symptoms and encourage early ED presentation with resultant increased reperfusion therapy rates for AMI. The study took place in 44 hospitals in 20 pair-matched communities in five U.S. geographic regions. Eligible study subjects were non-institutionalized patients without chest injury (aged > or =30 years) who were admitted to participating hospitals and who received a hospital discharge diagnosis of AMI (ICD 410); n = 4,885. For outcome assessment, patients were excluded if they were without survival data (n = 402), enrolled in thrombolytic trials (n = 61), receiving reperfusion therapy >12 hours after ED arrival (n = 628), or missing symptom onset or reperfusion times (n = 781). The applied intervention was an educational program targeting community organizations and the general public, high-risk patients, and health professionals in target communities. The primary outcome was a change in the proportion of AMI patients receiving early reperfusion therapy (i.e., within one hour of ED arrival or within six hours of symptom onset). Trends in reperfusion therapy rates were determined after adjustment for patient demographics, presenting blood pressure, cardiac history, and insurance status. Four-month baseline was compared with the 18-month intervention period.

RESULTS

Of 3,013 selected AMI patients, 40% received reperfusion therapy. Eighteen percent received therapy within one hour of ED arrival (46% of treated patients), and 32% within six hours of symptom onset (80% of treated patients). No significant difference in the trends in reperfusion therapy rates was attributable to the intervention, although increases in early reperfusion therapy rates were noted during the first six months of the intervention. A significant association of early reperfusion therapy use with ambulance use was identified.

CONCLUSIONS

Community-wide educational efforts to enhance patient response to AMI symptoms may not translate into sustained changes in reperfusion practices. However, an increased odds for early reperfusion therapy use during the initiation of the intervention and the association of early therapy with ambulance use suggest that reperfusion therapy rates can be enhanced.

Fish oil reduces cholesterol and arachidonic acid levels in plasma and lipoproteins from hypercholesterolemic chicks

The value of fish oil for prevention and/or treatment of human atherosclerosis has not been fully established. This study shows that replacement of saturated fat in young chick diet with menhaden oil produced a significant reversion of the hypercholesterolemia previously induced by coconut oil feeding. Fish oil also produced a clear decrease of plasma triacylglycerol levels. Coconut oil increased the percentages of 12:0 and 14:0 fatty acids, while menhaden oil increased those of 20:5 n-3 and 22:6 n-3. Percentages of 20:4 n-6, 18:2 n-6 and 18:1 n-9 significantly decreased by fish oil addition to the diet. Total cholesterol, phospholipid and protein contents of high and low density lipoproteins increased by coconut oil feeding. When coconut oil was replaced by menhaden oil, total cholesterol was significantly reduced in high, low and very low density lipoproteins. All chemical components of VLDL were decreased by menhaden oil feeding. Our results show a strong hypocholesterolemic effect of menhaden oil when this fat was supplemented to hypercholesterolemic chicks. The clear decrease found in arachidonic acid content of chick plasma and lipoproteins may contribute to the beneficial effects of fish oil consumption by lowering the production of its derived eicosanoids.

Alterations in 3-hydroxy-3-methylglutaryl-CoA reductase mRNA concentration in cultured chick aortic smooth muscle cells

We observed and compared alterations in 3-hydroxy-3-methylglutaryl (HMG)-CoA reductase at the transcriptional level in unsynchronized, three-passage cultures of smooth-muscle cells from the aorta of chicks fed on a control diet (C-SMC) and those of chicks fed on a similar diet plus cholesterol (Ch-SMC). Alterations in reductase mRNA concentrations in senescent cultures were much lower. We used a modification of the competitive (c) reverse transcription polymerase chain reaction method, using a Thermus thermophilus DNA polymerase (Tth pol) to quantify the very scarce species of HMG-CoA reductase mRNA in samples of cytoplasmic SMC mRNA. We cloned and sequenced a 199 bp cDNA fragment of chicken HMG-CoA reductase, which encoded a region of 66 amino acids belonging to the catalytic domain of the enzyme. HMG-CoA reductase mRNA concentrations from young C-SMC cultures rose 3.89-fold 4 h after the change of medium and returned to base levels between 8 to 12 h afterward. Concentrations in Ch-SMC cultures increased less (2.36-fold) 8 h after the change to fresh medium. Increases in reductase mRNA in senescent cultures of Ch-SMC and C-SMC measured under similar conditions were only 1.28- and 1.39-fold, respectively.

Dietary fish oil reduces cholesterol and arachidonic acid levels in chick plasma and very low density lipoprotein

The mechanisms involved in the hypolipidemic effects of fish oil have not been clearly established. This study shows that supplementation of 10% menhaden oil to the chick diet for 7 days produced a significant hypocholesterolemia and hypotriglyceridemia. Fatty acid composition of chick plasma drastically changed by the same dietary manipulation. Percentages of 20:5 and 22:6 n-3 fatty acids strongly increased, while percentages of 20:4 n-6, 18:2 n-6, and 18:1 n-9 significantly decreased. Changes observed in the relative percentages were parallel to those obtained in the amount of each fatty acid. Ratio of n-3/n-6 clearly decreased in plasma by fish oil feeding. Total cholesterol and triacylglycerol contents decreased in high density lipoprotein (HDL) but did not change in low density lipoprotein (LDL). All chemical constituents of very low density lipoprotein (VLDL) significantly decreased after the first week of menhaden oil supplementation to the diet. Similar modifications in fatty acid composition of the three lipoprotein fractions were also found. Our results suggest that the hypocholesterolemic effects of fish oil may be mediated by the depletion in VLDL synthesis and secretion into the chick plasma. On the other hand, the strong decrease found in the arachidonic acid (AA) content of chick plasma and lipoproteins may contribute to the beneficial effects of fish oil consumption by lowering the production of its derived eicosanoids.