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At least 19 recordsLinked to original sources
PubMed1979

Morphology of the hemostatic plug in human skin wounds: transformation of the plug.

The transformation of hemostatic plugs in human skin wounds was studied in vivo after bleeding had stopped. Standardized bleeding time incisions were made on the dorsal side of the forearm of four normal male volunteers. The wounds were excised by punch biopsy 10 minutes, 30 minutes, or 2 hours after they had been made and studied by light and electron microscopy. The wounds were filled with red blood cells, and a network of fibrin strands was found in the wound, particularly near transected vessels. Polymorphonuclear leukocytes were encountered within transected vessels and at 2 hours also in the wounds and in concentric rings around the vessels up to 0.5 mm. from the wound. On top of the wounds a superficial scab, consisting of red blood cells and presumably air-dried proteins, had formed. Hemostatic plugs were found at the ends of transected blood vessels. At 10 minutes the plugs consisted of largely degranulated platelets which showed strong interdigitation. Fibrin was still absent from the center of the plugs. At 30 minutes the platelets became less densely packed, and small fibrin fibers were deposited between the platelets in large peripheral areas of the plugs. At 2 hours some of the platelets had assumed rounded shapes with few interdigitations and larger spaces between them. Areas in the plug with platelets that had lost their integrity alternated with areas where platelets still had their cytoplasmic matrix and were interdigitated. Fibrin fibers were especially demonstrable between the degenerated platelet vesicles. This occurred everywhere in small hemostatic plugs and in the periphery of larger plugs. In one individual it was also observed in the center of large hemostatic plugs. In the other individuals fibrin was present centrally as amorphous dark staining material which was fibrillar in tangential sections.

Adult↗
PubMed1984

The haemostatic plug in haemophilia A: a morphological study of haemostatic plug formation in bleeding time skin wounds of patients with severe haemophilia A.

Haemostatic plug formation in four patients with severe haemophilia A (VIII:C less than 1%) was studied in skin biopsies taken at 3, 10 and 30 min and 2 h after a template bleeding time wound had been made. The primary haemostatic plug showed relatively minor changes, consisting of a delay in platelet degranulation and interdigitation. Some platelet aggregates not attached to vessels were encountered in the wound. Subsequently the primary haemostatic plug changed into a firm stable degranulated mass of interdigitated platelets. The major abnormality occurred during the fibrinous transformation. At 2 h many haemostatic plugs consisted of a thin peripheral layer of fibrin and platelet remnants around a central area containing red and white blood cells with a varying amount of plasma and only relatively few fibrin fibres. These observations suggest that fibrin formation in the periphery of the plug is less dependent of factor VIII than in central areas. The lack of fibrin formation in the centre of the plug compensating for the platelet lysis at 2 h may have caused the central erosion of the plug.

Adult↗
PubMed1981

Dual functions of bacteriophage T4D gene 28 product: structural component of the viral tail baseplate central plug and cleavage enzyme for folyl polyglutamates. I. Identification of T4D gene 28 product in the tail plug.

The T4D bacteriophage gene 28 product is a component of the central plug of the tail baseplate, as shown by the following two independent lines of evidence. (i) A highly sensitive method for radioactive labeling of only tail baseplate plug components was developed. These labeled plug components were incorporated by a complementation procedure into new phage particles and were analyzed by radioautography after sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Three new structural proteins were found in addition to the three known tail plug proteins (i.e., gP29, gP27, and gP5). One of the three newly identified components had a molecular weight of 24,000 to 25,000 and appeared to be a product of T4D gene 28. (ii) Characterization of mutants of Escherichia coli bacteriophage T4D which produced altered gene 28 products also indicated that the gene 28 product was a viral tail component. T4D 28(ts) phage particles produced at the permissive temperature had altered heat labilities compared with parent T4D particles. We isolated a single-step temperature revertant of T4D 28(ts) and found that it produced phage particles which phenotypically resembled the original T4D particles. Since the properties of the phage baseplate components usually determine heat lability, these two changes in physical stability after two sequential single mutations in gene 28 supported the other evidence that the gene 28 product was a viral baseplate component. Also, compared with parent T4D particles, T4D 28(ts) and T4D 28am viral particles adsorbed at different rates to various types of host cells. In addition, T4D 28(ts) particles exhibited a different host range than parent T4D particles. This T4D mutant formed plaques with an extremely low efficiency on all E. coli K-12 strains tested. We found that although T4D 28(ts) particles adsorbed rapidly and irreversibly to the E. coli K-12 strains, as judged by gene rescue experiments, these particles were not able to inject their DNA into the E. coli K-12 strains. On the other hand, the T4D 28(ts) revertant had a plating efficiency on E. coli K-12 strains that was quite similar to the plating efficiency of the original parent, T4D. These properties of phage particles containing an altered gene 28 product supported the analytical finding that the gene 28 product is a structural component of the central plug of the T4D tail baseplate. They also indicated that this component plays a role in both host cell recognition and viral DNA injection.

Adsorption↗
PubMed1990

[Experiments of contamination with bacteria while transfusion between the newly developed porous polymer plug and by air needle plug].

We newly developed a transfusion plug that has an air passage of polymer porous material (I Cap). This porous polymer material theoretical does not pass the infectious microorganisms. We experimented contaminations during the transfusions by I Cap and that using air needles. Trypticated soy broth was used for the experiments. Experiments of transfusion in a dusty environment revealed that the transfusions by air needles got 100% contamination and that by I Cap was 0%. The experiments in a clinic room transfusions also revealed that air needle resulted in 30.3% contamination but on the contrary 0% with the I Cap. Dusty air was flown under high pressure (1.5 atmospheric pressure) through the same filter of I Cap for 30 minutes into the trypticated soy broth. These experiments revealed that the filter did not permeate bacteria and that transfusions with air needle was contaminated with dust.

Air↗
PubMed1994

Plug the lung until it grows (PLUG): a new method to treat congenital diaphragmatic hernia in utero.

Fetal lungs normally produce fluid that flows through the upper airway into the amniotic fluid. In fetuses with congenital diaphragmatic hernia (CDH), obstructing the flow of lung fluid may expand the lungs and propel the viscera from the chest, alleviating the pulmonary hypoplasia associated with CDH. To test this hypothesis, left-sided diaphragmatic hernias were created in sixteen 75-day-gestation fetal lambs (full-term, 145 days). At 120 days, the trachea was ligated in eight lambs; it was left unligated in the other eight. At 135 to 140 days, the fetuses were delivered, and a tracheostomy performed. Newborns were ventilated for 1 hour and then killed. Blood gas analysis was performed at 0,5,20,40, and 60 minutes. Lung dry weight, DNA, protein, and lipid analyses, as well as plasma cortisol measurements were performed. At autopsy, in the ligated lambs, the abdominal viscera was reduced from the thorax; however, the unligated lambs had viscera completely occupying the left chest. The lungs of the ligated lambs had a higher dry weight (4.22 +/- 1.37 g/kg v 1.95 +/- 0.59 g/kg; P =.001), DNA (193.8 +/- 90.5 mg/kg v 91.5 +/- 66.4 mg/kg; P = .02), and protein (1798 +/- 691.6 mg/kg v 766.6 +/- 201 mg/kg; P = .004). Lung saturated phosphatidyl choline (SPC) levels, DNA:protein ratio, and plasma cortisol were not different between the groups. Neonatal Po2 at 60 minutes was higher in the ligated group (179.4 +/- 127.0 mm Hg v 60.9 +/- 62.4 mm Hg; P < .05), and Pco2 was lower (44.1 +/- 21.4 v 83.9 +/- 23.5; P < .05) in the ligated group.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

The urethral plug II: an alternative treatment in women with genuine urinary stress incontinence.

An improved design of the recently developed urethral plug was evaluated for the treatment of women with genuine urinary stress incontinence. The plug consists of an oval meatal plate, a soft stalk and 1 or 2 spheres along the stalk with fixed distances between the meatal plate and the spheres. Inside the stalk is a removable semi-rigid guide pin to ease insertion. Forty women were randomly allocated to treatment with either the 2-sphere or the 1-sphere plug during period 1 (2 weeks). In period 2 (2 weeks) the patients used the other plug. They then continued with what they judged to be the better plug in period 3 (2 months). Eighteen patients (45%) completed period 3 with the "preference" plug and 17 were subjectively and objectively continent or improved. Fourteen of these women preferred the 2-sphere device. The plugs were equally effective in patients with mild or severe incontinence. To accommodate variations in urethral length and to avoid the loss of plugs, the devices are available in different lengths. Six women developed urinary tract infections and 2 of these had a plug in the bladder. The urethral plug is an effective treatment in a group of women with stress incontinence. Removal by hand is advisable in order to avoid retention of plugs in the bladder.

Adult↗
PubMed1992

Leukocyte plugging in vivo in skeletal muscle arteriolar trees.

To provide quantitative data on leukocyte plugging and to estimate its effects on blood flow resistance in the microcirculation, in vivo observations of leukocyte plugging of capillaries were made in all branches of 27 terminal arteriolar trees in spinotrapezius muscles of anesthetized Sprague-Dawley rats. The durations of 1,257 observed plugs had a lognormal distribution with a median of 0.12 s. Of 596 branches, 211 experienced at least one plug; this subpopulation had a median plugging frequency of 0.016/s and a median plugging fraction (plugging frequency times average duration) of 0.28%. A new variable, the network occlusion fraction, was defined to quantify plugging in a whole arteriolar tree. Applying in vivo data to a model relating plugging to resistance increases resulted in a lognormal distribution of resistance increases with a median of 1.6%. Each of the resistance increases that were greater than 3% was due to one or two individual leukocytes that plugged a capillary for greater than 30 s. The results suggest that, under physiological conditions, leukocyte plugging has little effect on blood flow resistance.

Animals↗
PubMed1993

Effects of ear plugging on single-unit azimuth sensitivity in cat primary auditory cortex. I. Evidence for monaural directional cues.

1. Single-unit recordings were carried out in primary auditory cortex (AI) of barbiturate-anesthetized cats. Neurons, sensitive to sound direction in the horizontal plane (azimuth), were identified by their responses to noise bursts, presented in the free field, that varied in azimuth and sound pressure level (SPL). SPLs typically varied between 0 and 80 dB and were presented at each azimuth that was tested. Each azimuth-sensitive neuron responded well to some SPLs at certain azimuths and did not respond well to any SPL at other azimuths. This report describes AI neurons that were sensitive to the azimuth of monaurally presented noise bursts. 2. Unilateral ear plugging was used to test each azimuth-sensitive neuron's response to monaural stimulation. Ear plugs, produced by injecting a plastic ear mold compound into the concha and ear canal, attenuated sound reaching the tympanic membrane by 25-70 dB. Binaural interactions were inferred by comparing responses obtained under binaural (no plug) and monaural (ear plug) conditions. 3. Of the total sample of 131 azimuth-sensitive cells whose responses to ear plugging were studied, 27 were sensitive to the azimuth of monaurally presented noise bursts. We refer to these as monaural directional (MD) cells, and this report describes their properties. The remainder of the sample consisted of cells that either required binaural stimulation for azimuth sensitivity (63/131), because they were insensitive to azimuth under unilateral ear plug conditions or responded too unreliably to permit detailed conclusions regarding the effect of ear plugging (41/131). 4. Most (25/27) MD cells received either monaural input (MD-E0) or binaural excitatory/inhibitory input (MD-EI), as inferred from ear plugging. Two MD cells showed other characteristics. The contralateral ear was excitatory for 25/27 MD cells. 5. MD-E0 cells (22%, 6/27) were monaural. They were unaffected by unilateral ear plugging, showing that they received excitatory input from one ear, and that stimulation of the other ear was without apparent effect. On the other hand, some monaural cells in AI were insensitive to the azimuth of noise bursts, showing that sensitivity to monaural directional cues is not a property of all monaural cells in AI. 6. MD-EI cells (70%, 19/27) exhibited an increase in responsiveness on the side of the plugged ear, showing that they received excitatory drive from one ear and inhibitory drive from the other. MD-EI cells remained azimuth sensitive with the inhibitory ear plugged, showing that they were sensitive to monaural directional cues at the excitatory ear.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1986

Ultrastructure of proteinaceous bladder plugs in male rats.

Proteinaceous plugs in the bladder (bladder plugs) were found in male rats with an incidence of 14.1 to 17.8% in ages ranging from 10 weeks to 2 years. No evidence of urinary obstruction was found due to the plugs, but they appeared to irritate the bladder epithelium mechanically causing denudation. Consequently, exfoliated epithelial cells were incorporated into the plugs. Early in development, the plugs consisted of loosely organized eosinophilic masses with fine eosinophilic granules and fenestrated filaments in which eosinophilic globules were suspended. The components of plugs were similar to that contained in seminal vesicles. Subsequently, the plugs became more compact in structure with formation of densely interwoven amphophilic trabeculae containing exfoliated cells and spermatozoa. The periphery of the plugs was surrounded by exfoliated cells, cellular debris, eosinophilic granular materials and spermatozoa. Under electron microscopy, the eosinophilic granules surrounding the plugs were dense aggregates of electron-dense globules and vesicles derived from disintegrated bladder epithelium. The amphophilic trabeculae had a dense compact granular structure consisting of densely aggregated protein globules with a filamentous network. The intertrabecular proteinaceous material had a spongy like structure consisting of sparsely scattered protein globules with fine fenestrated filaments. Proteinaceous plugs having exfoliated cells and spermatozoa were found also in the male accessory sex glands. The plugs in the urinary bladder or male sex accessory glands appeared to be developed from back-flow of semen following ejaculatory disturbance.

Aging↗
PubMed1990

The urethral plug: a new treatment modality for genuine urinary stress incontinence in women.

A new modality, the urethral plug, was used to treat 22 women with genuine urinary stress incontinence. The plug is made of thermoplastic elastomer (Kraton G), and consists of a meatal plate, a soft stalk and 1 or 2 spheres along the stalk. The spheres were located according to the result of the urethral pressure profile. The midpoint of the proximal sphere was placed at the bladder neck and the distal sphere was placed just above the maximum urethral pressure point. At voiding the plug was removed and afterwards a new plug was inserted. The plug with 2 spheres was tested in week 1 (period 1) and the plug with only the distal sphere was tested in week 2 (period 2). A total of 22 patients completed period 1. Eight patients did not complete period 2, mostly due to either unchanged incontinence during period 1 or a repeated loss of the plug with 1 sphere. In periods 1 and 2, 73 and 79% of the patients were subjectively and objectively continent or improved. A total of 14 patients completed both periods. Eight patients preferred the plug with 2 spheres, 1 preferred the other plug and 5 had no preference. The side effects were few. This preliminary study shows that the urethral plug seems to be a promising alternative treatment for female genuine urinary stress incontinence.

Equipment Design↗
PubMed1995

[The urethral plug--an alternative treatment of women with urinary stress incontinence].

A developed urethral plug was evaluated for the treatment of women with genuine urinary stress incontinence. The plug consists of an oval meatal plate, a soft stalk and one or two spheres along the stalk with fixed distances between the meatal plate and the spheres. Inside the stalk is a removable semi-rigid guide pin to ease insertion. Forty women were randomly allocated to treatment with either the two-sphere or the one-sphere plug during period one (two weeks). In period two (two weeks) the patients used the other plug. They then continued with what they judged to be the better plug in period three (two months). Eighteen patients (45%) completed period three with the "preference" plug and 17 were subjectively and objectively continent or improved. Fourteen of these women preferred the two-sphere device. The plugs were equally effective in patients with mild or severe incontinence. Six women developed urinary tract infections and two of these had a plug in the bladder. The urethral plug is an effective treatment in a group of women with stress incontinence. Removal by hand is advisable in order to avoid retention of plugs in the bladder.

Adult↗
PubMed1990

Structural plugs at microtubule ends may regulate polymer dynamics in vitro.

Microtubules contain in their lumens distinct structures (plugs) that influence their dynamic behavior in vitro. As observed by electron microscopy, plugs are stain-occluding structures 10-30 nm in length that occur along the lengths and at the ends of microtubules. Plugs occur at a frequency of 20-40% at the ends of microtubules assembled from cycled microtubule protein containing MAPs. While the composition of plugs is not known, preliminary evidence suggests that they are accretions of tubulin, that they are labile, and that they are more common in preparations containing MAPs. When polymers are induced to depolymerize by endwise subunit dissociation, the frequency of plugged microtubule ends increases transiently, suggesting that plugs temporarily stabilize microtubules. The functional significance of plugs may be that they prevent the sudden complete loss of microtubules through catastrophic disassembly. It is possible that plugs, by slowing the rate of disassembly, enable a polymer to add GTP-tubulin subunits, thereby forming a stabilizing GTP-cap. These observations suggest that plugs may stabilize polymers and account for the frequent transitions from shortening to growing phases that characterize dynamic instability.

Animals↗