Effects of fixation for immunohistochemistry on tissue concentrations of substance P and somatostatin determined by radioimmunoassay.
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Animals↗
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[Short-term results of modified chevron osteotomy with soft tissue technique and guide wire fixation--a prospective study].
AIM: A Chevron osteotomy with lateral soft-tissue release was performed at our department in 1993. In 1994 a prospective study to evaluate the temporary Kirschner wire fixation was started. Aim of this prospective study was to analyse the short-term clinical and radiological results with special attention to stability, necroses, and luxation of the first metatarsal head. METHOD: Between February 1994 and October 1995 45 patients (55 feet) were treated with a Chevron osteotomy combined with a lateral soft-tissue release and temporary Kirschner wire fixation. The average follow-up was 33.9 months. All patients were seen and evaluated preoperatively and at a minimum follow-up of 24 months using a standardized questionnaire based on the Hallux metatarsophalangeal interphalangeal Scale (HMIS) of the American Foot and Ankle Society. RESULTS: Results of the survey of patient satisfaction revealed excellent and good results in 83%, fair in 8%, and poor in 9%. The median HMIS at final follow-up was 86.9 pints of 100 points. The average hallux valgus angle correction was 19.8 (from 28.7 to 8.9) and the average first intermetatarsal angel correction was, 8.2 (from 14.4 to 6.2). No avascular necrosis of the first metatarsal head and no loss of correction were noted. In one case a luxation of the metatarsal head was observed. CONCLUSION: Combining the Chevron osteotomy with an excessive lateral soft-tissue release increases the likelihood of instability of the metatarsal head and consecutive loss of correction. The temporary Kirschner wire fixation increases the stability of the Chevron osteotomy and prevents the loss of correction. The disadvantage of this method is, that the wire has to be removed after 6 weeks.
Adult↗
External fixation and infection of soft tissues close to fracture localization.
We evaluated the method of external fixation for stabilization of unstable closed and open first-degree diaphyseal fractures of long bones of lower extremities in 19 patients with infections of soft tissues close to the fracture location. The results are compared with those of another group (n = 392) of patients, with similar fractures without infections close to the fracture site, treated with inner stabilization methods. In the first group of patients, we noticed postoperative osteitis of the tibia in two cases (10%), but no pseudarthrosis or lesions of important blood vessels. In the second group of patients, the incidence of postoperative osteitis was 8.6% (n = 34) and the incidence of pseudarthrosis was 2% (n = 8). Among these patients, three lesions of important blood vessels were diagnosed. Our conclusion is that when the method of external fixation is used in combination with skillful operative techniques, the infection of soft tissues near the fracture location has no principal influence on the frequency of osteitis.
Croatia↗
Influence of thread design on bioabsorbable interference screw insertion torque during retrograde fixation of a soft-tissue graft in synthetic bone.
PURPOSE: Bioabsorbable interference screw design may influence biomechanical characteristics. This study compared the insertion torque and load at failure characteristics of 2 types of screws during retrograde fixation of a soft-tissue graft. TYPE OF STUDY: Biomechanical study. METHODS: Eight matched pairs of doubled 100-mm long tibialis anterior allografts were prepared and fixed in appropriately sized tunnels created in 10 lb/ft 3 (0.16 g/cm3) dense synthetic bone blocks using screws of similar length and root and thread diameter designed with either a large buttress thread with a smaller taper or small buttress thread with a larger taper. Insertion torque was measured at one-third, two-thirds, and full screw insertion. After the graft fixation constructs were mounted in a servohydraulic-testing device with the loading axis aligned directly with the tunnel and preloaded to 25 N, they were cycled 3 times from 0 to 50 N, and then subjected to a 20 mm/minute traction force to failure. RESULTS: All constructs failed by graft slippage past the screw. Mean maximum load at failure (360.5 +/- 68 N v 341.6 +/- 58 N, P = .2) and stiffness (63.6 +/- 16 N/mm 2 v 66.4 +/- 14 N/mm 2 , P = .89) was similar between constructs fixed with a large buttress thread small-taper screw and small buttress thread large-taper screw, respectively. The small buttress thread screw with a large taper displayed greater mean insertion torque at one-third insertion (4.1 +/- 0.57 in-lb v 3.2 +/- 0.49 in-lb, P = .03), whereas the large buttress thread screw with a small taper displayed greater mean insertion torque at full insertion (11.1 +/- 0.74 in-lb v 9.4 +/- 1.3 in-lb, P = .012). Mean differences were not observed at two-thirds screw insertion (P = .12). CONCLUSIONS: Large buttress thread small-taper screws displayed biomechanical fixation characteristics comparable to small buttress thread large-taper screws. CLINICAL RELEVANCE: Given reports of superior screw-graft-bone tunnel contact area, these biomechanical results suggest that use of a large buttress screw with a small taper may be preferable for retrograde soft-tissue graft fixation.
Absorbable Implants↗
[Experimental studies of the effect of fixation time on ultrasound extinction in formalin-fixed testicular tissue].
The influence of fixation time on the ultrasound damping was investigated in vitro in both normal and altered formalin-fixed testicular tissue. By means of ultrasound spectroscopy the ultrasound damping coefficient alpha is estimated. The results of measurements in different time intervals after onset of fixation did show that in both normal and altered testicular tissue only slight changes of ultrasound damping was found. Therefore, the influence of fixation time could be neglected.
Fixatives↗
Complement fixation activities with rat tissue antigens of sera in hepatic diseases.
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Acute Disease↗
[Impulse cytophotometry determination of the DNA content of paraffin-fixed neuroblastoma].
The aim of the study was to develop a method to obtain a single cell suspension from paraffin fixated neuroblastoma tissue for measuring the DNA content by flow cytometry, and to detect possible correlation between the histological grading and the DNA stemline, and to relate these findings to the patients' prognosis. 51 samples of the fixated neuroblastoma tissue were measured. It was possible to determine the DNA content in 38 probes of the material. 79% of the evaluated samples showed aneuploid DNA stemlines, 21% showed euploid stemlines. Despite the small number of probes it was found, that in relation to the histological grading of neuroblastoma a lower grade of malignancy correlated with an euploid DNA content and a higher grade of malignancy correlated with an aneuploid DNA content. A correlation between DNA stemlines and the patients' prognosis was not found.
Adolescent↗
Effects of trypsinization and microwave treatment on lectin labelling of microglial cells in paraffin-embedded sections from pre- and postnatal bovine brains.
The effects of microwave heat treatment on lectin histochemical staining of microglial cells with Griffonia simplicifolia B4 isolectin (GSA I-B4) and Ricinus communis agglutinin-I (RCA-I) in paraffin-embedded pre- and postnatal bovine brain tissue fixed in two different fixatives (Bouin's fluid and 4% neutral buffered formaldehyde) were examined, and the results compared with lectin labelling obtained in untreated and trypsinized serial sections. The results indicate that lectin labelling of bovine microglial cells depends on the kind of lectin applied, the fixative used for tissue preservation, the isotype of microglia to be labelled, and the pretreatment of tissue sections. In brain tissue fixed in Bouin's fluid, GSA I-B4 staining of both microglial isotypes, i.e., amoeboid and ramified microglial cells, was achieved without trypsinization. Staining of sections with RCA-I, however, yielded negative results both on untreated and on trypsinized sections. These findings suggest that species-specific differences in the density of binding sites accessible to GSA I-B4 and RCA-I, respectively, may exist. Pretreatment of sections by microwave irradiation had different effects depending on the lectin and fixative used and on the microglial isotype to be stained. Microwave heat treatment of sections prior to incubation with RCA-I enabled the labelling of amoeboid and ramified microglial cells. The latter cell type, however, was exclusively stained in brain tissue fixed in Bouin's fluid. With GSA I-B4, exclusively the labelling of ramified microglial cells in sections fixed in Bouin's fluid was improved. It is assumed that by microwave pretreatment of sections from bovine brain the access of both lectins to their receptors, i.e., D-galactose residues on microglial cells, may be facilitated.
Animals↗
125I uptake competing with iodine absorption by the thyroid gland following povidone-iodine skin application.
Povidone-iodine solution is widely used to disinfect the skin surface or prevent suppuration during human and animal surgery. Using radioisotope 125I, we examined whether iodine may be absorbed and then concentrated in the thyroid gland when povidone-iodine solution is applied to the skin of rats or mice. The competition for 125I uptake was examined in mice and rats after the application of povidone iodine to the skin. We also traced the process of absorbed 125I in the thyroid glad during the fixation for tissue preparations. Povidone-iodine applied to the skin significantly reduced the uptake of 125I both in mice and rats. Significant flux of 125I from the thyroid gland in povidone-iodine treated animals was noted during the thyroid fixation of tissue preparations. From these results, povidone-iodine application to the skin instead of stable KI administration may be practical for preventing the uptake of 125I by the thyroid gland during 125I compound administration for medical therapy. In animal experiments concerning thyroid functions, careful attention must be paid when povidone-iodine is used for disinfection in animal surgery.
Administration, Cutaneous↗
[Management of compound high energy injuries of the limbs--lessons and recommendations].
We treated 49 patients with high energy injuries of the limbs between 1.1.94-31.12.97. They had sustained 61 fractures, 50 of which were open; 14 had bilateral injuries, and 3 had lost a limb. All fractures were stabilized on arrival with an A-O tubular external fixator. Soft tissue loss was covered by a combination of split skin graft and tissue flaps following repeated surgical debridement. After 10 days, or when all soft tissue defects were covered, the cantilever external fixation frame was exchanged for a hybrid ring which provided three-dimensional stability and allowed early full weight bearing and joint mobilization. The hybrid ring frame did not interfere with the care of soft tissue injuries. Furthermore, it kept the risk of developing deep infections to a bare minimum. At follow-up after a median of 20 months, 1 patient had developed osteomyelitis but all had returned to independent function.
Arm Injuries↗
HOG CHOLERA. 3. INVESTIGATION OF THE COMPLEMENT-FIXATION TEST FOR THE DETECTION OF THE VIRUS IN SWINE TISSUE.
The complement-fixation test was investigated as a means of detecting hog cholera virus in spleen from experimentally infected swine. Various methods of extracting the tissue for production of antigen are described and emphasis is placed on the necessity of using the modified direct complement-fixation test to obtain reactions. The tissue should be obtained from animals showing advanced clinical manifestations of the disease. Preferably, the tissue should be maintained frozen or at least well refrigerated. The results indicate that tissue from dead animals or from breeding sows should be avoided. The 77 per cent positive reactions obtained suggest the test could be of diagnostic value provided two or three samples are obtained from the same herd.
Animals↗
Nuclear morphometry in breast cancer: the influence of sampling rules and freezing of samples.
We studied nuclear morphometry of human breast cancer with special emphasis on two sources of variation: freezing prior to fixation and selection of measured objects on the basis of different sampling rules. Samples of 147 histologically verified invasive breast cancer cases were examined with a computer-based image overlay drawing system. Thirty-eight of the 147 samples of tissue frozen before embedding in paraffin were analyzed separately. Among the latter we found shrinkage of 35% and 46% (depending on the sampling rule) of the nuclear profile area as compared with samples not frozen before the standard tissue processing. These findings confirm that nuclear morphometry results from frozen and unfrozen tissue are not comparable. Frozen tissue later embedded in paraffin should not be used with prognostication models based on traditionally fixed tissue. In morphometry we applied two sampling rules that differed in the criteria used for selecting nuclei for measurement. We registered a significant difference in nuclear size and in the variation of nuclear size between the two sampling methods. Of the morphometric features studied, nuclear area was affected most. Finally, we examined the two sampling rules in light of the established prognosticators in breast cancer: tumor size, axillary lymph node status, and the Multivariate Prognostic Index (MPI). The two sampling rules resulted in different distributions of morphometric results in the prognostic groups. Our findings emphasize the significance of the sources of variation in nuclear morphometry. They also stress the need for well-standardized morphometric methods in predicting the outcome of breast cancer.
Breast Neoplasms↗
[Problems of distinction of normal, artificial, and pathological structures in mature human placental villi. II. Morphometrical studies on the influence of the mode of fixation (author's transl)].
Morphometrical relations of human placental villi from 14 normal placentas of the 38th to 42nd week of pregnancy terminated by Cesarean section were examined in relation to the method of fixation. Villous tissue was obtained from central areas of the in situ placenta with intact maternal circulation by means of puncture aspiration and punch biopsy. Further punch biopsies were performed 2, 5, 10 and 20 min after manual removal of the placenta. Semithin sections of these villi were photographed and examined morphometrically. The findings demonstrate clear effects on quantitative data as a result of the period of ischemia between manual removal and fixation of tissue. Significant changes of several parameters (mean trophoblastic volume, size of epithelial plates, volume of connective tissue, volume of fetal vessel lumina, etc.) occur as early as 2 min after separation of the placenta from the maternal circulation. They are mostly related to a collapse of intravillous vessels. The villous branches may be classified according to structure and morphometry, if they have been obtained under optimal conditions of fixation and prior to any vascular collapse.
Biopsy, Needle↗
Dynamic glutaraldehyde fixation of a porcine aortic valve xenograft. I. Effect of fixation conditions on the final tissue viscoelastic properties.
Sixty porcine aortic valves were fixed under dynamic conditions at specific durations, pressures and vibration rates in a 0.5% glutaraldehyde phosphate buffer (pH 7.4, 0.2 M). Tensile relaxation tests were performed at low through high extension rates (0.3, 3 and 30 mm s-1) and tissue denaturation temperatures were determined by the hydrothermal isometric tension method. Conventional statically fixed valves and fresh valves were used as controls. No differences between dynamic and static treatment were observed at pulsation rates above those expected in the physiological range (i.e. above 1.2 Hz) or at higher pressures such as 30 mmHg. However, differences in both stress relaxation rates and denaturation temperatures were delineated in milder fixation conditions, i.e. at low pressures (< 4 mmHg) and low vibration rates similar to that of the normal heart beat (approximately 1.2 Hz). In these conditions the relaxation rate of the dynamically fixed tissue (-7.4 +/- 0.7% of stress remaining per log(s)) was similar to that of the fresh tissue (-6.7 +/- 1.2% log(s-1)) and significantly higher than the statically treated tissue (-3.9 +/- 1.7% log(s-1)). The rates of stress relaxation appeared to be strain rate dependent in both radial and circumferential directions when the tissues were strained at physiological rates during testing (> approximately 15000% min-1). Dynamically treated valves showed higher denaturation temperatures (mean +/- SD) (89.4 +/- 0.5 degree C) compared with the statically fixed (82.7 +/- 1.4 degrees C) or untreated (fresh) valves (65.5 +/- 0.8 degree C). The results suggest a higher degree of internal cross-linking owing possibly to enhanced penetration of the glutaraldehyde reagent and a greater accessability of reactive cross-linking sites on the collagen molecules. Better stress relaxation rates are likely associated with an increase in potential shearing between adjacent collagen fibres thus preserving the natural stress-reducing mechanism of the fresh, untreated valves. The dynamically treated valves therefore possess characteristics that may enable them to better resist long-term mechanical fatigue and in vivo degradation.
Animals↗
Microvascular free-tissue transfer with rigid internal fixation for reconstruction of the mandible following tumor resection.
The authors described their experience using rigid internal fixation techniques in combination with free microvascular tissue transfer for the immediate reconstruction of mandibular defects following tumor ablation. The technique allows immediate return of jaw motion and limited function while assuring maintenance of occlusion and reasonable cosmesis.
Fracture Fixation, Internal↗
Effects of four different processing techniques on the microstructure of potatoes: comparison with fresh samples in the ESEM.
Four common scanning electron microscope (SEM) processing techniques involving freeze-substitution and chemical fixation were compared with fresh unprocessed samples imaged in an environmental scanning electron microscope (ESEM) using small pieces of potato tubers as test specimens. Potato tubers were chosen for this investigation because of their high moisture content and, consequently, the common need for extensive processing for conventional, high vacuum SEM imaging. ESEM results showed that the fresh unprocessed specimens were essentially unaltered, showing clear potato cell structure, morphology, and cell content. However, processed samples showed strong differences to the fresh samples: freeze-substituted specimens showed fine networks of material stretching across the surface of cells. These structures may represent fibrillar material or may be artifact caused during processing. Chemical fixation almost entirely destroyed the microstructure of these potato samples.
Cryopreservation↗
Insertion torque pullout strength relationship of soft tissue tendon graft tibia tunnel fixation with a bioabsorbable interference screw.
PURPOSE: The purpose of this study was to evaluate the relationship between insertion torque and the biomechanical characteristics of soft tissue tendon graft tibia fixation with a bioabsorbable interference screw. TYPE OF STUDY: Biomechanical study. METHODS: Doubled tibialis anterior allografts (n = 20, length = 100 mm, diameter = 9 mm) prepared for anterior cruciate ligament (ACL) reconstructions were divided into 3 groups. Maximum insertion torque was measured as grafts were fixed by the same surgeon with a 10-mm diameter, 35-mm long screw in a 7-mm diameter tunnel (dilated to 9 mm) created in either 0.16 or 0.32 g/cm3 dense synthetic bone or cadaveric tibiae (0.84 +/- 0.15 g/cm2). Tensile testing to construct failure was then performed. RESULTS: All constructs failed by tunnel pullout. Higher density synthetic bone had greater load at failure than lower density synthetic bone (486.6 +/- 83.8 v 271.6 +/- 52.6 N, P <.0001) and a slightly greater proportion of variance could be explained in synthetic bone (R2 = 0.74, P <.0001) than in cadaveric tibiae (R2 = 0.64, P =.017). Higher density synthetic bone displayed greater stiffness than lower density synthetic bone (68.1 +/- 21.6 v 37.7 +/- 11.2 N/mm, P =.012) and a higher proportion of variance could be explained in cadaveric tibiae (R2 = 0.72, P =.008) than in synthetic bone (R2 = 0.48, P =.012). Greater insertion torque levels were seen in higher density synthetic bone (2.97 +/- 0.35 v 1.24 +/- 0.06 Nm, P <.0001) than in lower density synthetic bone, and a higher proportion of variance could be explained in synthetic bone (R2 = 0.94, P <.0001) than in cadaveric tibiae (R2 = 0.74, P =.006). CONCLUSIONS: Strong relationships were evident between insertion torque, bone mineral density (BMD) and load to failure across constructs. Differences between the synthetic bone groups and cadaveric tibiae, however, suggest the influence of mixed cortical and cancellous bone, nonuniform structural patterning, and differing BMD levels and distributions in the cadaveric tibiae. CLINICAL RELEVANCE: Soft tissue graft tibial tunnel fixation is directly related to insertion torque and BMD. Synthetic models with mixed bone characteristics are needed to more accurately depict human tibiae during fixation testing.
Absorbable Implants↗
Angioarchitecture of the CNS, pituitary gland, and intracerebral grafts revealed with peroxidase cytochemistry.
Blood vessels of the fetal, neonatal, and adult subprimate and primate CNS, including circumventricular organs (e.g., median eminence, pituitary gland, etc.), and of solid CNS and nonneural (anterior pituitary gland) allografts placed within brains of adult mammalian hosts were visualized with peroxidase cytochemistry applied in three ways: to tissues from animals injected systemically with native horseradish peroxidase (HRP) or peroxidase conjugated to the lectin wheat germ agglutinin (WGA) prior to perfusion fixation; to tissues from animals infused with native HRP into the aorta subsequent to perfusion fixation; and to tissues from animals fixed by immersion and incubated for endogenous peroxidase activity in red cells retained within blood vessels. In neonatal and adult animals receiving native HRP intravascularly, non-fenestrated vessels contributing to a blood-brain barrier were outlined with HRP reaction product when tetramethylbenzidine (TMB) as opposed to diaminobenzidine (DAB) was used as the chromogen; fenestrated vessels of circumventricular organs were not discernible due to the density of extravascular reaction product. Fenestrated and non-fenestrated cerebral and extracerebral blood vessels exposed to bloodborne WGA-HRP were visible when incubated in TMB and DAB solutions. Native HRP infused into the aorta of fixed animals likewise labeled non- fenestrated vessels throughout the brain upon exposure to TMB or DAB but obscured fenestrated vessels of the circumventricular organs. Endogenous peroxidase activity of red cells, seen equally well with TMB and DAB, outlined blood vessels throughout the cerebral gray and white matter and all circumventricular organs in fetal, neonatal, and adult animals. Application of the three peroxidase cytochemical approaches to study the development or absence of a blood-brain barrier in intracerebral allografts demonstrated that the vascularization of day 16-19 fetal/1 day neonatal CNS allografts is not well defined prior to 7 days following intracerebral placement of the grafts. CNS allografts secured from donor sites expected to possess a blood-brain barrier exhibited blood vessels that were not leaky to HRP injected intravenously in the host. Fenestrated blood vessels associated with anterior pituitary allografts were evident prior to 3 days posttransplantation within the host brain and permitted blood-borne HRP in the host to enter the graft and surrounding host brain parenchyma.
Animals↗