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PubMed2003

Integration of single cell injection, cell lysis, separation and detection of intracellular constituents on a microfluidic chip.

A microfluidic system was developed for the analysis of single biological cells, with functional integration of cell sampling, single cell loading, docking, lysing, and capillary electrophoretic (CE) separation with laser induced fluorescence (LIF) detection in microfabricated channels of a single glass chip. Channels were 12 microm deep and 48 microm wide, with a simple crossed-channel design. The effective separation channel length was 35 mm. During sampling with a cell suspension (cell population 1.2 x 10(5) cells per mL in physiological salt solution), differential hydrostatic pressure (created by adjusting liquid levels in the four reservoirs) was used to control cell flow exclusively through the channel crossing. Single cell loading into the separation channel was achieved by electrophoretic means by applying a set of potentials at the four reservoirs, counteracting the hydrostatic flow. A special docking (adhering) procedure for the loaded cell was applied before lysis by repeatedly connecting and disconnecting a set of low potentials, allowing precise positioning of the cell within the separation channel. Cell lysis was then effected within 40 ms under an applied CE separation voltage of 1.4 kV (280 V cm(-1)) within the working electrolyte (pH 9.2 borate buffer) without additional lysates. The docked lysing approach reduced dispersion of released intracellular constituents, and significantly improved the reproducibility of CE separations. Glutathione (GSH) was used as a model intracellular component in single human erythrocyte cells. NDA derivatized GSH was detected using LIF. A throughput of 15 samples h(-1), a retention time precision of 2.4% RSD was obtained for 14 consecutively injected cells. The average cellular concentration of GSH in human erythrocytes was found to be 7.2 [times] 10(-4)+/- 3.3 x 10(-4) M (63 +/- 29 amol per cell). The average separation efficiency for GSH in lysed cells was 2.13 x 10(6)+/- 0.4 x 10(6) plates per m, and was about a factor of 5 higher than those obtained with GSH standards using pinched injection.

Electrophoresis, Capillary↗
PubMed2005

Continuous particle separation in a microchannel having asymmetrically arranged multiple branches.

A new method for continuous size separation and collection of particles in microfabricated devices, asymmetric pinched flow fractionation (AsPFF), has been proposed and demonstrated. This method improves the separation scheme of pinched flow fractionation (PFF), which utilizes a laminar flow profile inside a microchannel. In this study, multiple branch channels with different channel dimensions were arranged at the end of the pinched segment, so that the flow rate distributions to each branch channel were varied, and a large part of the liquid was forced to go through one branch channel (drain channel). In the proposed channel system, the flow profile inside the microchannel was asymmetrically amplified, enabling the separation of one-order smaller particles compared with PFF. After introducing the method, we examined the effect of the asymmetric amplification by controlling the outlet of the drain channel. Also, a mixture of 1.0 approximately 5.0 microm particles was separated, and erythrocytes were successfully separated from blood. The results indicate that the AsPFF method could be applied to the separation of much smaller-size particles, since more precise separation can be achieved simply by changing the geometries of branch channels.

Journal Article↗
PubMed2005

DC-dielectrophoretic separation of microparticles using an oil droplet obstacle.

A new dielectrophoretic particle separation method is demonstrated and examined in the following experimental study. Current electrodeless dielectrophoretic (DEP) separation techniques utilize insulating solid obstacles in a DC or low-frequency AC field, while this novel method employs an oil droplet acting as an insulating hurdle between two electrodes. When particles move in a non-uniform DC field locally formed by the droplet, they are exposed to a negative DEP force linearly dependent on their volume, which allows the particle separation by size. Since the size of the droplet can be dynamically changed, the electric field gradient, and hence DEP force, becomes easily controllable and adjustable to various separation parameters. By adjusting the droplet size, particles of three different diameter sizes, 1 microm, 5.7 microm and 15.7 microm, were successfully separated in a PDMS microfluidic chip, under applied field strength in the range from 80 V cm-1 to 240 V cm-1. A very effective separation was realized at the low field strength, since the electric field gradient was proved to be a more significant parameter for particle discrimination than the applied voltage. By utilizing low strength fields and adaptable field gradient, this method can also be applied to the separation of biological samples that are generally very sensitive to high electric potential.

Electrophoresis, Microchip↗
PubMed2006

A microfluidic device for continuous, real time blood plasma separation.

A microfluidic device for continuous, real time blood plasma separation is introduced. The principle of the blood plasma separation from blood cells is supported by the Zweifach-Fung effect and was experimentally demonstrated using simple microchannels. The blood plasma separation device is composed of a blood inlet, a bifurcating region which leads to a purified plasma outlet, and a concentrated blood cell outlet. It was designed to separate blood plasma from an initial blood sample of up to 45% inlet hematocrit (volume percentage of cells). The microfluidic network was designed using an analogous electrical circuit, as well as analytical and numerical studies. The functionality of this device was demonstrated using defibrinated sheep blood. During 30 minutes of continuous blood infusion through the device, all the erythrocytes (red blood cells) traveled through the device toward the concentrated blood outlet while only the plasma was separated at the bifurcating regions and flowed towards the plasma outlet. The device has been operated continuously without any clogging or hemolysis of cells. The experimentally determined plasma selectivity with respect to blood hematocrit level was almost 100% regardless of the inlet hematocrit. The total plasma separation volume percent varied from 15% to 25% with increasing inlet hematocrit. Due to the device's simple structure and control mechanism, this microdevice is expected to be used for highly efficient continuous, real time cell-free blood plasma separation from blood samples for use in lab on a chip applications.

Fluorescent Dyes↗
PubMed2000

Gray scale and color Doppler sonography in the third stage of labor for early detection of failed placental separation.

OBJECTIVE: The purpose of this study was the characterization of normal and abnormal third stage placental separation using gray scale and color Doppler sonography. METHODS: The third stage of labor was examined in 62 patients using gray scale and color Doppler sonography. After identification of placental basal plate vessels by color Doppler sonography, the placentation site was examined throughout the third stage with combined gray scale and color Doppler mode. Placental separation from the myometrium was defined clinically and correlated to cessation of color Doppler detected blood flow in basal plate vessels. RESULTS: Three sonographic phases of placental separation were: (1) latent = interval between delivery of the fetus and beginning placental separation; (2) detachment = mono- or multiphasic shearing off of the placenta and (3) expulsion = interval between completed separation and vaginal delivery of the placenta. In 57 cases with clinically normal placental separation blood flow between placenta and myometrium ceased immediately after delivery of the fetus during the latent period. In five cases manual or instrumental removal was necessary because of placenta adhaerens in one case and placenta accreta in four cases. The latter showed maternal blood flow from the myometrium deep into the placenta beyond the latent phase. CONCLUSION: Cessation of blood flow between the basal placenta and myometrium following delivery of the baby is the sonographic hallmark of normal placental separation. Persistent blood flow demonstrated by color Doppler sonography is suggestive of placenta accreta.

Adult↗
PubMed2003

Prevalence of bacterial faecal pathogens in separated and unseparated stored pig slurry.

AIMS: To examine the prevalence and diversity of bacterial faecal pathogens in unseparated slurry, separated solids and liquid fractions from a commercial pig farm. METHODS: A total of 43 stored slurry specimens originating from a fattening house over the period February-April 2002 were analysed, consisting of unseparated (n = 14) slurry, separated solids (n = 16) and separated liquid (n = 13). Specimens were examined for the presence of five bacterial pathogens including Salmonella spp., Shigella spp., Campylobacter spp., Escherichia coli O157 and Yersinia enterocolitica. Selective enrichment and plating methods were employed for detection of Salmonella spp. and Campylobacter spp. and conventional selective plating techniques for the remaining genera. Antibiogram profiles to 12 antibiotic agents were obtained for all Salmonella isolates obtained. RESULTS: Salmonella spp. were identified in all components of the slurry specimens, whereas Campylobacter spp. was only recovered from the unseparated and separated liquid fractions. In both cases, the separated liquid fraction had the highest prevalence of pathogens and the separated solid fraction had the lowest prevalence. None of the slurry specimens examined were positive for E. coli O157:H7, Shigella spp. or Y. enterocolitica. Twenty-nine isolates of Salmonella were recovered from the slurry specimens, comprising seven serovars, of which Salmonella manhattan was the most prevalent, accounting for over half [15 of 29 (51.7%)] of all Salmonella isolates. Salmonella anatum, Salm. derby, Salm. give, Salm. heidelberg, Salm. simi and Salm. stanley serovars were also recovered. All Salmonella isolates were sensitive to ampicillin, augmentin (amoxicillin/clavulanic acid), chloramphenicol, ciprofloxacin, gentamicin, kanamycin and trimethoprim, but has variable resistance to tetracycline (100%), sulphonamides (84.6%), furazolidone (38.5%), nalidixic acid (15.4%) and streptomycin (15.4%). The majority (57.7%) of isolates displayed antibiotic resistance to at least two antibiotic agents, followed by 34.6% of isolates being resistant to three agents and the remainder (7.7%) being resistant to four antibiotics. SIGNIFICANCE AND IMPACT OF THE STUDY: This study demonstrated a marked reduction in the prevalence of Campylobacter and Salmonella in the solids component of separated pig slurry. The adoption of control processes such as aeration of slurry prior to its spread onto agricultural land and newer approaches to pathogen reduction should be investigated, to reduce the transmission of pathogens from pig slurry to the environment.

Animal Husbandry↗
PubMed1998

Platelet collection with the Amicus and the AS.TEC 204 blood cell separators.

BACKGROUND: Platelet collection with two new blood cell separators was compared with respect to platelet yield, separation efficiency, white cell (WBC) contamination, and measures of component quality. Both machines offer a menu for the collection of a desired platelet yield. The harvesting of a definite platelet yield is a means of collecting a standardized therapeutic platelet dose. STUDY DESIGN AND METHODS: One hundred seventy-two platelet collections were carried out with different protocols in the two devices (Amicus and AS.TEC 204). For that reason, healthy donors underwent plateletpheresis procedures using the continuous- and discontinuous-flow systems. Separations with a definite endpoint volume and the option of collecting a desired platelet yield of 5.5 x 10(11) in the Amicus and 3.3 x 10(11) in the AS.TEC 204 machine were investigated. RESULTS: With the Amicus blood cell separator, platelet yield (5.02+/-0.46 x 10[11]) and separation efficiency (66.9+/-6.2%) were significantly higher than those with the AS.TEC 204 (3.02+/-0.62 x 10[11] and 46.4+/-6.7%, respectively). There was less deviation between the platelet yield and the desired platelet yield in the AS.TEC 204 machine than in the Amicus device. WBC contamination was 2.06+/-2.91 x 10(6) in components obtained from the AS.TEC 204 machine, and 87.5 percent of the platelet concentrates had a WBC content <5 x 10(6). None of the components from the Amicus device contained more than 5 x 10(6) WBCs. Except for platelet morphology score, measures of component quality were almost equal in the platelet concentrates obtained from the studied machines. CONCLUSION: Platelet yield and separation efficiency were significantly higher in the Amicus blood cell separator. The collection of a desired platelet yield was better achieved with the AS.TEC 204 device.

Blood Component Removal↗
PubMed2003

Three-dimensional imaging clarifies the process of tracheoesophageal separation in the rat.

BACKGROUND/PURPOSE: The process of tracheoesophageal separation during early development of the foregut has been disputed and has led to difficulties explaining how congenital abnormalities of the trachea and esophagus might occur. This study clarifies the embryogenesis of tracheoesophageal separation by using sequential 3-dimensional imaging at crucial stages of foregut development. METHODS: Timed pregnant Sprague Dawley rats were killed at days 11, 11.5, 12, 12.5, and 13. The embryos were harvested, histologically sectioned, and stained with H&E. Digitized photographs were taken of sequential serial transverse sections and their tracings layered in a 3-dimensional rendering program before being "skinned" to produce a 3-dimensional object. RESULTS: The first respiratory structures to develop are the bronchi on day 11.5. They are evident first as bulges on the ventrolateral wall of the foregut approximately two thirds of the way between the lowest pharyngeal pouch and the level of the hepatic diverticulum and pancreatic buds. Lateral grooves dorsal to the respiratory bud on the lateral walls extend cranially. On day 12 the lateral bulges have developed into the 2 main bronchi, although the trachea is yet to separate from the foregut. On days 12.5 to 13 the trachea progressively elongates, and by day 13 tracheoesophageal separation is complete. CONCLUSIONS: After the main bronchi have developed, the trachea forms when the ventral component of the foregut is "cut" away from the dorsal component. There is an area of apoptosis at the point of tracheoesophageal separation, and, as the embryo grows, this causes the separation point to stay at a constant distance from the pharynx. Meanwhile, the trachea and esophagus distal to it increase dramatically in length. The area immediately caudal to the initial point of tracheoesophageal separation ultimately forms the stomach.

Animals↗
PubMed2005

Separation of gas mixtures using a range of zeolite membranes: a molecular-dynamics study.

Gas separation efficiencies of three zeolite membranes (Faujasite, MFI, and Chabazite) have been examined using the method of molecular dynamics. Our investigation has allowed us to study the effects of pore size and structure, state conditions, and compositions on the permeation of two binary gas mixtures, O(2)N(2) and CO(2)N(2). We have found that for the mixture components with similar sizes and adsorption characteristics, such as O(2)N(2), small-pore zeolites are not suited for separations, and this result is explicable at the molecular level. For mixture components with differing adsorption behavior, such as CO(2)N(2), separation is mainly governed by adsorption and small-pore zeolites separate such gases quite efficiently. When selective adsorption takes place, we have found that, for species with low adsorption, the permeation rate is low, even if the diffusion rate is quite high. Our results further indicate that loading (adsorption) dominates the separation of gas mixtures in small-pore zeolites, such as MFI and Chabazite. For larger-pore zeolites such as Faujasite, diffusion rates do have some effect on gas mixture separation, although adsorption continues to be important. Finally, our simulations using existing intermolecular potential models have replicated all known experimental results for these systems. This shows that molecular simulations could serve as a useful screening tool to determine the suitability of a membrane for potential separation applications.

Journal Article↗
PubMed1988

Cell expansion and single-cell separation induced by colchicine in suspension-cultured soybean cells.

Single plant cells have been obtained without the preparation of protoplasts by culturing pieces of soybean callus tissue with colchicine. Cell expansion and separation were evoked by colchicine (1 mM) within a week of culture. Microscopic observation showed that cells took on a spherical shape in the presence of colchicine and then separated into single cells. Addition of colchicine to the culture medium did not affect the composition of cell wall polysaccharides, but a uronic acid-rich extracellular polysaccharide appeared during cell expansion and separation. Addition of microtubule stabilizers, glycerol (300 mM) or dimethyl sulfoxide [3% (vol/vol)], inhibited the secretion of the polysaccharide as well as cell expansion and separation. The extracellular polysaccharide elicited by colchicine was isolated by ion-exchange chromatography on DEAE-Sepharose and gel filtration on Sepharose CL-6B from the conditioned medium of colchicine-treated soybean cells. The purified 18-kDa polysaccharide immediately enhanced cell expansion and separation when added to soybean callus tissue cultured in medium containing colchicine, even at low concentrations (0.1 mM). The polysaccharide was composed of galacturonic acid and, after digestion with a pectinase preparation, had no effect on the cells. Methylation analysis suggests that the polysaccharide consists of approximately 100 sequential alpha-1,4-galacturonic acids. The galacturonan increased the viability of separated cells cultured in medium containing colchicine, and the single cells obtained did not produce a wound-response callose. (Aminoethoxyvinyl)glycine, a specific inhibitor of ethylene production, extensively decreased the cell expansion and separation but did not inhibit the formation of the extracellular polysaccharide, suggesting that the polysaccharide may exert its effect by stimulating ethylene production.

Journal Article↗
PubMed1997

Ability of laying hens to negotiate horizontal perches at different heights, separated by different angles.

1. This paper describes how birds move between horizontal perches at different heights with different angles separating them, using the time to complete the task and the number of birds failing to indicate ability. 2. For the first experiment, 4 groups of 15 birds (ISA Brown) were subjected to each of the experimental treatments (using three perches with angles of 0 degree (horizontal control), 30 degrees, 45 degrees or 60 degrees between them). The birds were required to move upward between the perches for each treatment and then to move downward between the perches, as a second part of the experiment. 3. Birds moving up between the perches took significantly longer at 60 degrees than at any other angle. No birds failed to complete the task. 4. For birds moving downward between the perches, the median time to complete the task increased significantly with angle. Furthermore, the number of birds failing to complete the task increased with angle. 5. A second experiment was conducted to test whether the vertical or horizontal component of distance affected birds' ability to negotiate perches separated by different angles. 6. For the second experiment 4 groups of 10 Lohmann Brown laying hens were subjected to each of the following treatments: two horizontal perches separated by 30 degrees or 60 degrees and either directly, horizontally or vertically separated by a set distance of 50 cm. Birds were required to move both up and down between perches. 7. Birds negotiated horizontally-separated perches more successfully at 30 degrees than at 60 degrees. However, when the vertical distance between the perches was 50 cm there was no significant difference in the ability of birds to move downward at 30 degrees or 60 degrees. For birds moving upward, 60 degrees was easier to negotiate than 30 degrees. 8. The vertical and horizontal separations, as well as the different angles affected the ability of birds to move between perches. There was a general decreasing trend in ability with increasing vertical separation between perches. 9. The findings are important in terms of arrangements of perches to improve bird welfare. To minimise the risk of injury, the angle between perches at different heights should be no more than 45 degrees, and the horizontal and vertical distances between these perches minimised, to allow the birds to be able to move downwards more easily.

Animal Welfare↗
PubMed2001

Effect of solid-liquid separation on BOD and VFA in swine manure.

Fresh swine manure was sieved into seven different particle size categories, i.e., <0.075 mm, < 0.15 mm, < 0.25 mm, < 0.5 min, < 1.0 mm, < 1.4 mm, and < 2.0 mm. Manure was stored in seven PVC columns and sampled every 5 days up to 30 days. Manure samples were analyzed for total volatile fatty acids (VFAs), 5-day biochemical oxygen demand (BOD5), total solids (TS), total suspended solids (TSS), and total volatile solids (TVS). Two parameters (VFAs and BOD5) were used to determine the odor generation potential of the test manure. The results showed that total VFAs correlated well with BOD5 (R2 = 0.8297). The levels of ISS only explained 40% of BOD5 and 46% of VFAs, both of which increased with storage time, regardless of solid particle sizes. Also, the data inferred that most of the odorous compounds (measured by VFA and BOD levels) were contained in manure solid particles less than 0.075 mm. These cannot be removed by commercial mechanical separators with screen size ranging from 0.5 to 3.0 mm. With an average separation efficiency of 25% for most commercially available mechanical separators, the removal efficiencies of BOD5 and VFAs were as low as 10% and 12%, respectively. These findings cannot justify the use of solid-liquid separation tocontrol odor. Data also showed that for swine manure, it is critical to run separation treatment within the first ten days after the manure is excreted to potentially improve the separation efficiency. After ten days, the degradation of TSS was accelerated due to the increased biological activities, which may greatly reduce the separation efficiency.

Animals↗
PubMed2005

The impact of emotional stress early in life on adult voluntary ethanol intake-results of maternal separation in rats.

The combination of genetic and environmental factors determines the individual vulnerability for excessive ethanol intake, possibly leading to dependence. The environmental influences early in life represent examples of determinant factors for adult behaviour and can be protective as well as risk factors. Maternal separation is one model to examine the long-term consequences of early environmental experiences on neurochemistry and behaviour, including drug-taking behaviour in experimental animals. In the present review, findings from studies using repeated short and prolonged periods of maternal separation, with emphasis on effects on voluntary ethanol intake in rats with or without a genetic predisposition for high voluntary ethanol intake, are summarized. Despite some contradictory results, the general picture emerging shows that short periods of maternal separation during the postnatal period result in a lower adult voluntary ethanol intake in male rats. Prolonged periods of maternal separation were found to induce a high voluntary ethanol intake in male rats, including rats with a genetic predisposition for high ethanol intake. Results from the literature also show that changes were not just related to time of separation but were also related to the degree of handling. Interestingly, in terms of voluntary ethanol intake, female rats were generally not affected by postnatal maternal separation. The reasons for these sex differences need further investigation. In terms of neurobiological consequences of maternal separation, conclusive data are sparse and one of the future challenges will, therefore, be to identify and characterize underlying neurobiological mechanisms, especially in the individual animal.

Alcohol Drinking↗
PubMed2003

Solids separation coupled with batch-aeration treatment for odor control from liquid swine manure.

Previous studies on solids/liquid (S-L) separation for odor control from swine manure indicated that the practice might not technically be feasible because of the complexity of removing the fine particles, which are usually the major source of the odor problems. This study coupled S-L separation by sedimentation with an aeration treatment to quickly break down the fine as well as dissolved solids. Results showed that S-L separation of manure prior to aeration, at the same level of aeration, took only 1.5 days compared to 3 days needed for the control, to bring down volatile fatty acids (VFAs) to the "threshold of unacceptable level". In addition, it took 2.3 and 5 aeration-days for VFAs to reach the "acceptable level" for the separated liquid manure and the control, respectively. Results also showed that within the three weeks of post-aeration storage, the VFAs in the separated liquid manure consistently stayed 13.5 folds below the acceptable level. In the unseparated manure, the VFAs gradually increased upwards from 2.2 folds below acceptable level achieved at the end of aeration treatment, to 1.38 folds below the acceptable level at the end of the third week of storage and looked poised to definitely rise above the acceptable level in a matter of days. A strong relationship (R=0.99) between pH and the VFAs in the manure suggested that; degradation of VFAs rendered manure more basic as shown by the increase in pH. After only three days of aeration, the oxidation reduction potential (ORP) in the separated liquid manure stabilized at a much higher level of -15 mV, while the ORP in unseparated manure stabilized at a much lower level of -200 mV. The S-L separation treatment thus significantly improves the oxygen transfer efficiency, which in turn significantly reduces the aeration power needed to maintain adequate ORP if prolonged aeration is desired.

Animals↗
PubMed1983

The separation of neutral glycosphingolipids from mammalian erythrocytes by droplet counter-current chromatography (DCC).

In a previous paper (Otsuka, H. & Yamakawa, T. (1981) J. Biochem. 90, 247-254), we reported the separation of acidic glycolipids by droplet counter-current chromatography using 500 columns with a commercially available DCC apparatus and described the precise conditions of the separation. In this paper, separation of neutral glycolipids from rabbit and human erythrocytes by DCC is described. For efficient separation of neutral glycolipids, addition of a definite amount of benzene was required. The solvent system of chloroform: benzene: methanol: water = 50: 50: 70: 20 gave clear separation of these glycolipids and further modification of this solvent system to chloroform: benzene: methanol: water = 50: 25: 65: 30 gave satisfactory results for the separation of Globoside I from human erythrocytes due to the difference between the amide linked fatty acids. Also under the same conditions, the clear separation of two peaks with blood group A activity was demonstrated by a hemagglutination inhibition test.

ABO Blood-Group System↗
PubMedDate not supplied

Separated flows in artificial organs. A cause of early thrombogenesis?

Separated flow is unavoidable in artificial blood-wetted devices. Surfaces bound by separated flows cause abnormal protein adsorption, then platelet adhesion and activation, and eventually thrombogenesis and embolization. A prolonged abnormal adsorption pattern is expected, especially in separated flows, as blood first displaces a wetting liquid during start-up of a device. The authors obtained patterns of immunoglobulin G (IgG), fibrinogen, and high molecular weight kininogen (HMK) adsorption in and near a separated flow. The flow was induced in flowing saline, replaced at time zero by plasma. The separated flow was induced behind a 4 mm bar introduced into a steady shear flow (Re = 26.4) in an apparatus designed so that the surface behind the bar was a standard glass microscope slide. The staining technique revealed the distribution of each protein of interest over the surface of the slide, and was applied to slides residing in the flow for 1, 5, 10, 30, and 60 min after the introduction of plasma (final dilution, 3.5% and 8.5%). Results show the expected, rapid disappearance of fibrinogen from surfaces near (but not in) the separated region, and prolonged appearance and even more prolonged disappearance of fibrinogen from the surface bounding the separated region. Slides removed from the apparatus, when exposed to a platelet suspension, showed that platelets adhered where fibrinogen was present on the surface.

Adsorption↗
PubMed1982

The stress of marital separation: intervention in a Health Maintenance Organization.

Relationships between life stress and illness form the basis of much current thinking and practice in psychosomatic medicine. This study examines a particular life stress, marital separation, in a controlled, prospective design. Participants are 237 Health Maintenance Organization [HMO] subscribers followed over a two-year period. Marital separation was experienced by 117 of these participants early in the two-year study period. A stratified random half of these separated individuals participated in a short-term psychoeducational group intervention, "Seminars for the Separated." Measures of psychosocial adjustment and medical utilization were analyzed to describe correlates of experiencing marital separation and to evaluate the intervention. Statistically significant increases in medical utilization by people experiencing marital separation were observed in comparisons with married control subjects. Much of this increased utilization is in the year surrounding the actual separation and is accounted for by mental health visits. Effects of the intervention were not evident until controls for baseline levels of medical utilization were introduced. Even then, intervention effects were slight. Methodological problems and implications for further study are presented.

Adult↗
PubMed2003

Maternal separation alters acquisition of ethanol intake in male ethanol-preferring AA rats.

BACKGROUND: Prolonged daily maternal separation can increase the risk for developing substance abuse, whereas brief maternal separation has been reported to induce positive behavioral effects, decrease voluntary ethanol intake and induce long-lasting changes in brain opioid peptides. The ethanol-preferring AA (Alko, Alcohol) rats have altered basal levels of endogenous opioid peptides that may relate to their high voluntary ethanol intake. The purpose of this study was to investigate whether maternal separation could affect acquisition of ethanol intake in AA rats. METHODS: The rat pups were exposed to 15 min (MS15) or 360 min (MS360) of maternal separation during postnatal day 1-21, while control rats were exposed to normal animal facility rearing. As adults, the male rats were gradually introduced to increasing concentrations of ethanol. Furthermore, the effect of restraint stress on voluntary ethanol intake was investigated. RESULTS: The MS15 rats reached a high voluntary ethanol intake later than MS360 and control rats. The MS15 rats had a lower ethanol intake and preference at 8% ethanol compared to MS360 rats and lower ethanol intake compared to control rats. MS15 rats also had a lower 10% ethanol intake in comparison with MS360 rats. Restraint stress decreased the ethanol intake in MS15 and MS360 rats, whereas the ethanol intake in control rats was unaffected. CONCLUSIONS: We have previously shown that prolonged periods of maternal separation in Wistar rats result in an increased ethanol intake later in life. This was not repeated in this study, using AA rats with an inherent high ethanol intake. However, it is shown that brief maternal separation can delay acquisition of high ethanol intake and in addition decrease voluntary ethanol intake and preference in AA rats. Maternal separation for 15 min is therefore suggested to protect against high voluntary ethanol intake later in life.

Alcohol Drinking↗