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PubMed1991

Effects of suspension-induced osteopenia on the mechanical behaviour of mouse long bones.

Whereas most studies of tail-suspension induced osteopenia have utilized rat femora, the present study investigated the effects of a 14 day tail-suspension on the mechanical behaviour of mice femora, tibiae and humeri. Force-deflection properties were obtained via three-point bending for long bones from suspended and control mice. Whole bone behaviour was characterized by converting the force-deflection values to stiffness, strength, ductility and energy parameters which were not normalized for specimen geometry. The effects of a systematic variation in the deflection rate over the range 0.1-10 mm min-1 were also evaluated. Statistical analysis indicated that the primary effect of the tail-suspension period was lowered bone mass which was manifested mechanically through lower values of the bone strength parameters. These effects were similar in the bones of both the fore and hind limbs. The results also demonstrated that the stiffness, ductility and energy characteristics were much less influenced by the tail-suspension. Whereas a significant dependence of the bone strength values upon deflection rate was observed for the femora and humeri, the other mechanical parameters were less sensitive. Based upon the nature of the physical and mechanical changes observed in the long bones following tail-suspension, the mouse appears to be a suitable animal model for the study of osteopenia.

Animals↗
PubMed1982

Anterior periosteal dermal suspension with suction curettage for lateral thigh lipectomy.

The standard excisional approach to lipectomy has now been expanded by the use of suction curettage either as an adjunct or a primary procedure. In severe cases of steatomeria (a term used to designate trochanteric obesity and eliminate the misuse of the term lipodystrophy), curettage serves to prepare and shape the flaps, while excision and "periosteal dermal suspension" are sometimes necessary to achieve adequate contour and lift. Periosteal anchoring ensures adequate permanent suspension and a tension-free closure. Achievement of lateral thigh contouring by an anterior approach is facilitated by the use of the suction curette. Undermining of the superior flap and contouring with suction, as well as overlapping the closure with buried dermal-fat suspension flaps, eliminates bulging above or below the incision. Periosteal dermal suspension decreases the possibility of scar widening and eventual ptosis, provides a fixation technique that permits more lift, and eliminates scarring from the lateral thigh. Lateral thigh suction lipectomy with periosteal dermal suspension has been done alone or in conjunction with buttock reduction or with medial thigh or abdominal lipectomy in 14 patients. The operating time was short, and the results were good with minimal morbidity.

Adipose Tissue↗
PubMed2000

Derivation of extracellular fluid volume fraction and equivalent dielectric constant of the cell membrane from dielectric properties of the human body. Part 1: Incorporation of fat tissue into cell suspension model in the arm.

The non-invasive characterisation of cell pathophysiology is clinically important. A cell suspension model is applied to derive the extracellular fluid (ECF) volume fraction and the equivalent dielectric constant of the cell membrane epsilon m from the dielectric properties of human arms. Frequency-dependent dielectric constants and electrical conductivities of arms are obtained from 35 surgical patients over a frequency range of 5-1000 kHz. The cell suspension model is applied to fit the data using a complex non-linear least-squares method. The arms show typical dielectric dispersions, although the cell suspension model yields a poor fitting in dielectric constants at lower frequencies and electrical conductivities at higher frequencies. In contrast, a new cell suspension model, taking into account the fat tissue component, remarkably improves the overall fitting performance, allowing estimation of the volume fractions of ECF (0.34 +/- 0.05) and fat tissue (0.16 +/- 0.04) and the equivalent epsilon m (23 +/- 9). The resulting estimates of the volume fraction of fat tissue are in good correlation with arm skinfold thickness (fat volume fraction of arm = 2.42 x 10(-3) x arm skinfold thickness (mm) + 0.099, R = 0.756, p < 0.0001). Therefore it is concluded that the newly derived cell suspension model is well suited for the description of the dielectric properties of human tissues and thus the derivation of the ECF volume fraction and equivalent epsilon m.

Adipose Tissue↗
PubMed1985

Zonal unit-gravity elutriation. A new technique for separating large cells and multicellular complexes from cell suspensions.

A new and simple technique, zonal unit-gravity elutriation, has been devised for separating very large cells, multicellular complexes, or small organisms from suspensions consisting mainly of small cells. The separation vessel is a conical chamber with an entrance at the lower, narrower part of the cone and an exit at the upper, wider part of the cone via a dome-shaped lid. A baffle at the entrance prevents turbulence from incoming fluid. Chambers of differing widths and wall slopes are chosen depending on the sedimentation rate of the particles to be separated. A small volume of the cell suspension is placed in the chamber on the bench in a cold-room. Medium stabilized by a shallow density gradient is pumped into the base of the chamber and ascends, creating a decreasing velocity gradient. Cells sediment at unit-gravity against this ascending counterstream, and are separated into bands according to sedimentation velocity. By adjusting the flow rate of the medium, different sizes of cells can be separated. Tumor cells can be enriched, and larger blast cells can be separated from small cells in lymphoid cell suspensions. The procedure produces complete separation of thymic nurse cells (epithelial-lymphoid complexes) from free thymocytes in digested thymus suspensions and produces substantial enrichment of thymic rosettes (macrophage-lymphoid complexes). A very favorable situation for applying this technique is the isolation of Taenia taeniaformis larvae, which can be completely purified from infected liver suspensions, representing a 4 X 10(5)-fold enrichment of the parasites, with high recovery, in a single 30 min operation.

Animals↗
PubMed1985

A method for flow cytometric cell cycle analysis of normal and psoriatic human epidermis based on a detergent/citric acid technique for suspension of nuclei.

A new method is described for flow cytometric cell cycle analysis of normal and psoriatic human epidermis, based on non-enzymatic tissue disaggregation. The epidermis was isolated by treatment with acetic acid and stored by freezing. After thawing, the epidermis was disintegrated into a nuclear suspension by 3 steps: incubation with dithiotreitol, whirling in a buffer (pH 7.4) with the non-ionic detergent Nonidet P40, EGTA, RNase and spermine, and whirling after addition of citric acid to a final concentration of 1% (pH 2.4). The suspension was stained with propidium iodide and filtered before flow cytometry. The yield of suspended nuclei was approximately 70% of the original number of cells in the tissue. The detergent/citric acid method was found to be preferable to an ultrasonication method previously used on human epidermis. All cell cycle and cell maturation stages were represented in the detergent/citric acid suspension, in contrast to the selection of immature G1, S and G2 stages with enzymatic methods. In the analysis of psoriatic epidermis inadequately matured (parakeratotic) cells were present in the suspension and had to be discriminated by gating on light scattering intensity, as they were not susceptible to lysis and did not stain properly. The fraction of S phase nuclei was on average 1.9% in normal and 7.7% in psoriatic epidermis, thus confirming the results of other investigators using enzymes. The presence of mitotic figures in the suspension was demonstrated by flow sorting. In this way the mitotic fraction was estimated to 0.06% in normal and 0.22% in psoriatic epidermis, confirming histological data of other investigators.

Biopsy↗
PubMed2000

Characterisation of extracellular polysaccharides from suspension cultures of members of the poaceae.

Microscopic examination of suspension- cultured cells of Phleum pratense L., Panicum miliaceum L., Phalarisaquatica L. and Oryza sativa L. showed that they were comprised of numerous root primordia. Polysaccharides secreted by these suspension cultures contained glycosyl linkages consistent with the presence of high proportions of root mucilage-like polysaccharides. In contrast, suspension-cultured cells of Hordeum vulgare L. contained mostly undifferentiated cells more typical of plant cells in suspension culture. The polysaccharides secreted by H. vulgare cultures contained mostly linkages consistent with the presence of glucuronoarabinoxylan. The soluble polymers secreted by cell-suspension cultures of Phleum pratense contained 70% carbohydrate, 14% protein and 6% inorganic material. The extracellular polysaccharides were separated into four fractions by anion-exchange chromatography using a gradient of imidazole-HCl at pH 7.0. From glycosyl-linkage analyses, five polysaccharides were identified: an arabinosylated xyloglucan (comprising 20% of the total polysaccharide), a glucomannan (6%), a type-II arabinogalactan (an arabinogalactan-protein; 7%), an acidic xylan (3%), and a root-slime-like polysaccharide, which contained features of type-II arabinogalactans and glucuronomannans (65%).

Cell Wall↗
PubMed2006

[A new approach to the transvaginal needle suspension technique after Raz. Technique and long-term results].

AIM: Our aim is to describe the surgical technique and to present a long-term evaluation of the results. MATERIALS AND METHODS: A total of 53 patients with stress incontinence underwent a Raz transvaginal needle suspension operation with the introduction of a polypropylene mesh strip (15x1.5-2 cm) pulled under the suspension threads. The suspension threads occur on the endopelvic fascia in order to support the bladder neck and to permit the function of the polypropylene mesh strip, which, however, does not take part in supporting the bladder neck. The same urologist carried out 53 consecutive operations with clinical evaluation at 6 months, 1 and 5 years after surgery. RESULTS: After 6 months, 51 of the patients (96.2%) reported remaining dry after increasing intra-abdominal pressure. Two (3.7%) still had stress incontinence symptoms. After 1 and 5 years, 47 (88.6%) were dry and urinated normally, with spontaneous disappearance of nightly enuresis in two and surgery for subvesicular obstruction in one. CONCLUSIONS: The introduction of a polypropylene mesh strip in the suspension threads in cases using the trasvaginal suspension technique has good, long-term results for the treatment of patients with stress incontinence.

Adult↗
PubMed2005

Long-term chronic complications from Stamey endoscopic bladder neck suspension: a case series.

UNLABELLED: Purpose/objective Long-term complications from anti-incontinence surgical procedures are rarely reported. We report on delayed presentation of complications relating to the synthetic bolster placed for the Stamey bladder neck suspension. MATERIALS AND METHODS: Patients undergoing re-operative surgery following prior Stamey endoscopic bladder neck suspension were selected from a surgical database. Four women with lower urinary tract and/or vaginal symptoms following prior Stamey endoscopic bladder neck suspension were identified. All patients had undergone removal of the bolster material by a single surgeon (ESR) at re-operation. Preoperative, operative, and postoperative inpatient and outpatient records were reviewed. RESULTS: Patients presented with a variety of symptoms including urinary incontinence, recurrent cystitis, vaginitis, and urinary frequency at 9, 11, 11, and 12 years after Stamey bladder neck suspension. In addition, two patients presented with recurrent, intermittent bloody vaginal discharge and two patients complained of recurrent urinary tract infections and irritative voiding symptoms. All patients underwent transvaginal excision of the Dacron bolster. Three patients also underwent placement of an autologous pubovaginal sling for symptomatic recurrent stress urinary incontinence. At a mean follow-up of 30 months all four patients were improved. There was no recurrence of vaginal discharge or urinary tract infections. Irritative voiding symptoms resolved. CONCLUSIONS: Delayed complications from surgically implanted synthetic materials can present many years after initial implantation. The clinical findings are often subtle and require a high degree of suspicion. Vaginal discharge and irritative urinary symptoms in patients with even a remote history of Stamey bladder neck suspension should prompt a thorough vaginal exam and cystoscopy. Excision of the bolsters can be performed and is usually followed by symptomatic improvement.

Aged↗
PubMed2002

Safety and efficacy of sacrospinous vault suspension.

The objective of the study was to determine the success rate and complications of sacrospinous vault suspension when performed by an experienced surgeon. Retrospective data collection was performed for 293 women who had undergone sacrospinous vault suspension at Mount Sinai Hospital, Toronto, between November 1993 and 19 December 1998. Primary outcome measures were complication rates (acute and long term) and success rate, with failure defined as any degree of vault prolapse requiring repeat operation, any degree of symptomatic isolated vault prolapse, or any vault prolapse at or beyond the introitus. Statistical analysis was performed using simple descriptive techniques. During the study period, 305 sacrospinous vault suspensions were performed; however, 12 cases were excluded because of inaccessible records. This study therefore comprised the remaining 293 cases: 129 at the time of vaginal hysterectomy, 5 with transvaginal cervical stump excision, 155 for post-hysterectomy vault prolapse, and 4 without hysterectomy. Two hundred had follow-up of 1 year or more, with maximum follow-up 5 years. Of these 200, there were 6 failures (3%). There were no acute hemorrhages and no deaths. There was a complaint of postoperative right buttock pain in 18 of the 293 procedures (6.1%), with this persisting on a chronic basis in 3 patients. Eight patients complained of new-onset postoperative dyspareunia. Nine patients had postoperative stress urinary incontinence, and 14 patients had de novo anal incontinence. Postoperatively, there were 17 patients with a cystocele and 7 with a rectocele. There were three other complications: one pelvic hematoma at the sacrospinous suspension site, one right foot drop which spontaneously resolved, and one case of pain in the right sciatic nerve distribution which spontaneously resolved. Forty-three patients complained of anal incontinence preoperatively, and 38 (88.4%) had the symptoms resolved postoperatively. It was concluded that, when performed by a surgeon experienced in the procedure, sacrospinous vault suspension is safe and effective, with a successful result at 1 year in more than 90% of cases, and rare major complications.

Adult↗
PubMed1998

Comparison of mesencephalic free-floating tissue culture grafts and cell suspension grafts in the 6-hydroxydopamine-lesioned rat.

Ventral mesencephalon (VM) of fetal rat and human origin grown as free-floating roller-tube (FFRT) cultures can survive subsequent grafting to the adult rat striatum. To further explore the functional efficacy of such grafts, embryonic day 13 ventral mesencephalic tissue was grafted either after 7 days in culture or directly as dissociated cell suspensions, and compared with regard to neuronal survival and ability to normalize rotational behavior in adult rats with unilateral 6-hydroxydopamine (6-OHDA) lesions. Other lesioned rats received injections of cell-free medium and served as controls. The amphetamine-induced rotational behavior of all 6-OHDA-lesioned animals was monitored at various time points from 18 days before transplantation and up to 80 days after transplantation. Tyrosine hydroxylase (TH) immunostaining of the histologically processed brains served to assess the long-term survival of grafted dopaminergic neurons and to correlate that with the behavioral effects. Additional cultures and acutely prepared explants were also fixed and stored for histological investigation in order to estimate the loss of dopaminergic neurons in culture and after transplantation. Similar behavioral improvements in terms of significant reductions in amphetamine-induced rotations were observed in rats grafted with FFRT cultures (127%) and rats grafted with cell suspensions (122%), while control animals showed no normalization of rotational behavior. At 84 days after transplantation, there were similar numbers of TH-immunoreactive (TH-ir) neurons in grafts of cultured tissue (775 +/- 98, mean +/- SEM) and grafts of fresh, dissociated cell suspension (806 +/- 105, mean +/- SEM). Cell counts in fresh explants, 7-day-old cultures, and grafted cultures revealed a 68.2% loss of TH-ir cells 7 days after explantation, with an additional 23.1% loss after grafting, leaving 8.7% of the original number of TH-ir cells in the intracerebral grafts. This is to be compared with a survival rate of 9.1% for the TH-ir cells in the cell-suspension grafts. Immunostaining for the calcium-binding proteins calretinin, calbindin, and parvalbumin showed no differences in the neuronal expression of these proteins between the two graft types. In conclusion, we found comparable dopaminergic cell survival and functional effects of tissue-culture grafts and cell-suspension grafts, which currently is the type of graft most commonly used for experimental and clinical grafting. In this sense the result is promising for the development of an effective in vitro storage of fetal nigral tissue, which at the same time would allow neuroprotective and neurotrophic treatment prior to intracerebral transplantation.

Amphetamine↗
PubMed1991

The long-term traffic safety impact of a pilot alcohol abuse treatment as an alternative to license suspensions.

During the 4-year period following a repeat driving under the influence (DUI) conviction, participants in 12-month treatment programs had worse overall traffic safety records than did recipients of license suspensions. The results from a series of analyses using repeated measures analysis of covariance showed that, in comparison with license-suspension recipients: (i) participants had significantly higher rates (70%) of nonalcohol-related accidents and convictions, (ii) participants had a significantly lower rate (9%) of alcohol-related convictions, but no difference was found on alcohol-related accidents, and (iii) participants had a significantly higher rate (30%) of total accidents (p less than .05). These results suggest that the use of license-suspension waiver as an incentive to participate in a drinking driver program had a negative impact on traffic safety. The predicted reductions in alcohol-related accidents among program participants did not occur, and reductions in nonalcohol-related accidents, which could have been achieved with license suspensions, were sacrificed. It was recommended that some other alternative besides license-suspension waivers be used as an inducement for repeat DUI offenders to participate in treatment.

Accidents, Traffic↗
PubMed1985

Intraperitoneal chromic phosphate P 32 suspension therapy of malignant peritoneal cytology in endometrial carcinoma.

Malignant peritoneal cytology in patients with endometrial carcinoma is a poor prognostic feature, identifying patients at high risk for early intra-abdominal recurrence. Between 1977 and January, 1983, 65 women with endometrial carcinoma who had malignant peritoneal cytology were treated with adjuvant intraperitoneal radioactive chromic phosphate P 32 suspension. Fifty-three patients (80%) were clinical Stage I, nine (14%) were Stage II, and three (7%) were clinical Stage III. Life-table estimates of disease-free survival were 89% for clinical Stage I patients and 94% for surgical Stage I patients beyond 24 months. One patient developed an intraperitoneal recurrence, four had simultaneous intraperitoneal and extraperitoneal recurrences, and six developed recurrences outside of the peritoneal cavity. Few significant acute complications occurred after therapy with radioactive chromic phosphate P 32 suspension. Chronic intestinal morbidity that required surgical correction was encountered in five of 17 patients (29%) who received adjuvant pelvic radiation, compared to none of the 48 patients (0%) who received only radioactive chromic phosphate P 32 suspension (p less than 0.001). Intraperitoneal instillation of radioactive chromic phosphate P 32 suspension is effective therapy for patients with malignant peritoneal cytology from endometrial carcinoma. Caution should be exercised when radioactive chromic phosphate P 32 suspension and external radiation therapy are combined.

Adenocarcinoma↗
PubMed1991

Allografts of CNS tissue possess a blood-brain barrier. II. Angiogenesis in solid tissue and cell suspension grafts.

Angiogenesis and patency of blood vessels were analyzed qualitatively in solid CNS and peripheral tissue syngeneic, allogeneic, and xenogeneic grafts and in individual cell suspension grafts of astrocytes, fibroblasts, PC12, and three additional tumor cell lines placed intracerebrally in adult host mice. Postgrafting survival times were 1 day through 4 weeks. The patency of graft vessels was determined in sections from immersion-fixed tissues incubated to reveal the endogenous peroxidase activity of host red cells trapped within the lumen of blood vessels. Additionally, horseradish peroxidase (HRP) was administered intravenously to live hosts; HRP labels host brain and graft vessels on the luminal surface and reveals the presence or absence of a blood-brain barrier (BBB) within the grafts. The origins of blood vessels supplying solid tissue xenografts were identified immunohistochemically with primary antibodies against host (athymic AKR mice) and donor (fetal Lewis rats) major histocompatibility complex (MHC) class I. Blood vessels supplying solid CNS grafts at 1-7 days post-transplantation were identified ultrastructurally and possessed interendothelial tight junctional complexes; however, they were not perfused with either host blood or blood-borne HRP prior to 8 days. Graft vessels at 10 days were outlined consistently by peroxidase-positive red cells in immersion-fixed material and labeled with blood-borne HRP. These vessels provided a BBB to the circulating HRP and exhibited interendothelial tight junctions. Evidence of angiogenesis within solid anterior pituitary grafts and the variety of cell suspension grafts was obtained prior to 3 days post-transplantation in immersion-fixed preparations; the vessels, with the notable exception of those supplying astrocyte cell suspensions, failed to present a BBB to blood-borne peroxidase. Endothelia in the solid pituitary allografts and the PC12 cell grafts were highly fenestrated and exhibited open interendothelial junctions; those in the tumor and fibroblast cell grafts, for the most part, appeared nonfenestrated, and many possessed open interendothelial junctional complexes. Immunostaining for host and donor MHC class I revealed that donor blood vessels predominate over host vessels in CNS xenografts and supply pituitary xenografts exclusively; in both preparations, donor vessels were not identified within the host CNS. Because cell suspension grafts were derived from endothelia-free preparations grown in culture, blood vessels supplying these grafts were necessarily of host CNS origin and manifested a morphological transformation from a BBB to a non-BBB endothelium. The data suggest that angiogenesis in solid CNS grafts placed into the adult host CNS, compared to similarly placed solid peripheral tissue/cell suspension grafts, is not rapid.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1984

A simple reliable assay for myeloperoxidase activity in mixed neutrophil-eosinophil cell suspensions: application to detection of myeloperoxidase deficiency.

Quantitation of myeloperoxidase (MPO) activity by guaiacol peroxidation (GP) assay is profoundly affected by the peroxidase present in eosinophils (EPO) that contaminate the granulocyte suspensions. Inclusion of 3-amino-1,2,4-triazole (AMT) in the GP assay permits quantitation of MPO activity in mixed neutrophil-eosinophil suspension because of the differential inhibition of EPO and MPO by AMT. Results show that: (1) the peroxidase activity of eosinophil-free granulocyte suspensions is not appreciably affected by AMT; (2) in the presence of AMT the peroxidase activities of granulocyte preparations containing different numbers of eosinophils are similar on a neutrophil basis, regardless of the number of eosinophils and correspond with the activity of eosinophil-free granulocyte suspensions; (3) AMT almost completely inhibits the activity of partially purified EPO, only slightly affecting the catalytic activity of partially purified MPO; (4) AMT completely inhibits the residual peroxidase activity of granulocyte suspensions from MPO-deficient subjects contributed by contaminating eosinophils. The GP assay in the presence of AMT was used to study the pattern of hereditary transmission of MPO deficiency. The genealogy derived on the basis of this assay was compatible with an autosomal recessive inheritance, in agreement with previously reported results, while no definite pattern of inheritance could be established by use of the GP assay without AMT. We suggest that the GP assay supplemented with AMT is the method of choice for detection of MPO deficiency, particularly partial deficiency.

Amitrole↗
PubMed1996

The surgical anatomy of needle bladder neck suspension.

OBJECTIVE: To define the surgical anatomy of needle bladder neck suspension in order to explain this operation's effect on urethral support and gain information useful in minimizing intraoperative complications. METHODS: Needle bladder neck suspension was carried out on two unembalmed, multiparous cadavers. After fixing the suspensory sutures in place, the pelvis of one cadaver was completely dissected. The second cadaver was serially sectioned at 1-cm intervals, and the sections were subjected to both anatomic and histologic examination. These findings were correlated with the findings noted during an autopsy dissection of a woman who previously had undergone needle bladder neck suspension at our institution and with our surgical experience with this operation. RESULTS: The plane of dissection used to enter the space of Retzius lay between the vaginal mucous membrane and the visceral endopelvic fascia. The point of entry into the retropubic space lay between the levator ani muscles and its superior fascia, lateral to the arcus tendineus fasciae pelvis, the paraurethral vascular plexus, and bladder neck. It was cephalad to the perineal membrane (urogenital diaphragm). The paraurethral supporting tissues incorporated in the suspensory suture included the portion of the endopelvic fascia that lies between the vagina and urethra and, usually, the arcus tendineus fasciae pelvis. Attaching the suspensory sutures in needle bladder neck suspension seems to stabilize the bladder neck by providing a new point of lateral fixation for its supporting endopelvic fascia. CONCLUSION: Needle bladder neck suspension stabilized the supportive fascia of the urethra, and vascular injury may be minimized by detailed knowledge of paraurethral anatomy.

Cadaver↗
PubMed1994

In situ and suspension protocols for chemically-induced mutation at the tk locus in L5178Y MOLY cells: dose response and colony size distribution.

We used EMS up to concentrations of 0.25 microliters/ml (292 micrograms/ml) to induce mutations at the tk locus in L5178Y MOLY cells, measured the cellular response by the in situ mutation assay protocol and compared these results to those obtained in a concomitant suspension assay. EMS induced mutagenic responses with both protocols. The mutant fraction for the solvent control was 89 mutants per million viable colonies for the suspension protocol and 426 mutations per million viable cells plated for the in situ protocol. These numbers increase to 447 and 2073 respectively, with 0.25 microliter/ml EMS treatment. Sizing curves indicated that the in situ protocol detected a greater proportion of smaller colonies than did the suspension protocol. Not only were the number of small colonies greater than large colonies in the in situ protocol, but their rate of increase was also slightly higher than that of the large colonies. The in situ protocol also reduces the time and cost of experimentally performing the assay compared to the suspension protocol. In this paper we compare the use of the suspension and in situ protocols to measure chemically-induced mutations and demonstrate that the latter method detects a larger fraction of induced mutations at the tk locus in L5178Y MOLY cells.

Animals↗
PubMed1985

Endothelial binding of transferrin in fractionated liver cell suspensions.

Several studies using crude liver cell suspensions incubated with labeled transferrin have led to a conclusion that hepatocytes have transferrin receptors. When a visual probe, which permits evaluation of transferrin binding to individual cells, was used, the binding was unexpectedly found to be limited to endothelial cells in liver cell suspensions. Neither hepatocytes nor Kupffer cells contained transferrin receptors. In the present study, we fractionated liver cell suspensions using metrizamide gradients and centrifugal elutriation to obtain hepatocytes, Kupffer cell and endothelial cell fractions of high purity. Incubation of these fractions with 125I- or 59Fe-labeled transferrin led to exclusive binding to endothelial cells but not hepatocytes nor Kupffer cells. Kinetic analysis demonstrated Kd of 1.9 X 10(-7) M, Bmax of 3.1 pmol/10(6) cells per min, corresponding to 2.1 X 10(5) molecules/cell per min. At 4 degrees C, the binding reached a steady-state plateau within 5 min. Comparison of our data with those of previous investigators demonstrates a consistency if we consider that crude liver cell suspensions are contaminated with 2-3% endothelial cells. Thus, the previously reported findings may be entirely due to the contamination of crude liver cell suspensions with a small number of endothelial cells.

Animals↗
PubMed1991

Effects of body suspension on soleus muscle fibres and spinal motoneurones in the rat.

1. After 14 days of body suspension, fibre type composition and fibre cross-sectional area in the soleus muscle of 17-week-old male Sprague-Dawley rats were investigated. Oxidative enzyme activity of soleus motoneurones in the spinal cord was also examined. 2. After suspension, soleus muscle weight decreased by 44.2%, the cross-sectional area of SO and FOG fibres decreased by 60.4% and 58.6%, respectively. 3. The percentage of fibre types was not changed by suspension. However, ATPase activity after alkaline preincubation was markedly inhibited in FOG fibres. 4. Oxidative enzyme activity of soleus motoneurones was not changed by suspension. 5. This study demonstrates that using mature animals body suspension induces atrophy of fast- and slow-twitch fibres accompanied with the selective inhibition in ATPase activity of fast-twitch fibres, and without changes in histochemical profiles of the corresponding motoneurones.

Animals↗