Tetrasomy 8 is associated with a major cellular proliferative advantage and a poor prognosis. two cases of myeloid hematologic disorders and review of the literature.

We report two cases of acute myeloid leukemia (AML) with tetrasomy 8 detected in patients' bone marrow samples using chromosome GTG-banding, fluorescence in situ hybridization (FISH) and primed in situ labeling (PRINS) techniques. Case 1 was a myelodysplastic syndrome (MDS) in transition to AML-M4 and case 2 was an AML-M2. In case 1, the tetrasomy 8 was found in 40% of metaphase cells and constituted the only chromosome abnormality. In case 2, it was accompanied by a double Ph, trisomy 18 and disomy Y and was found in 68% of metaphase cells. However, FISH and PRINS techniques revealed the coexistence of tetrasomy 8 and trisomy 8 in interphase nuclei of both cases. When the proportion of cells with tetrasomy 8 was compared between metaphases and interphase nuclei, it showed a much higher percentage of cells with tetrasomy 8 in metaphases than in interphase nuclei. Moreover, in case 2, although multi-PRINS and FISH-PRINS techniques showed other populations of interphase nuclei with different combinations of chromosome anomalies with respect to the copy numbers for chromosomes 8, 18, Y and Ph, only cells that contained either a single Ph or tetrasomy 8 plus trisomy 18, disomy Y, and double Ph could be seen in metaphases. This strongly suggests that tetrasomy 8 confers a higher proliferative advantage to cells. Our cases also show that the tetrasomy 8 is associated with a poor prognosis.

Physical characterization of unimplanted gel filled breast implants. Should old standards be revisited?

Physical characterization of unimplanted gel filled mammary prostheses was undertaken using both destructive and non-destructive test methods. Physical properties measured included mass, volume, optical transmittance, coefficient of kinetic friction, mechanical stiffness, dynamic response to a stationary random vibration, bursting strength, elasticity of the envelopes, and nuclear magnetic resonance relaxation times. The data obtained from this study will provide reference points for quantifying the rate of degradation of prostheses in past and current clinical use. Some of the test methods are suitable for use as routine quality control procedures to improve the uniformity of the properties and performance of breast prostheses. This investigation also showed that some currently used prostheses do not comply with the relevant American Society for Testing and Materials standards, or even with the manufacturers' own stated claims or specifications.

Increased expression of a novel leukocytic factor in patients with hemolytic anemia.

Misprimed polymerase chain reaction (PCR) products were generated from the crude leukocytic DNA extract of four of five patients with hereditary hemolytic anemia, during the course of exon 6 pyruvate kinase L gene amplification. These by-products, which originated from abundant mRNA templates, were not observed in seven healthy individuals. Two markers were cloned (GenBank accession numbers M64700 and M64701). We focused further studies on one of the human markers associated with hereditary hemolytic anemia, human DNA marker B (HUMDNAMB). HUMDNAMB is a 451-bp open reading frame that has never been described previously. The nucleic acid sequence region 303-416 is 63% homologous to a coding region of the bovine interferon alpha-A gene. Matrix analysis of the amino acid sequences reveals a structural similarity between the two proteins. The HUMDNAMB protein is expected to be larger than interferons, based on the size of its 2-kb messenger RNA detected by Northern blot in human leukocytes, fetal liver, and fetal intestine.

Hereditary nonspherocytic hemolytic anemia due to pyruvate kinase deficiency: a prevalence study in Quebec (Canada).

Fifty-eight cases of hereditary nonspherocytic hemolytic anemia due to pyruvate kinase deficiency were collected from both laboratories that have performed the assay since 1972 and from attending physicians in the province of Quebec. Using the postal addresses of the probands, a prevalence map was constructed according to the administrative regions of the province of Quebec. The prevalence was found to be higher in eastern Quebec (1/81,838) than in western Quebec (1/139,086). Fifty probands were of French Canadian origin whereas the remaining 6 were recent immigrants.

Soft filamentous woven polyester arterial prosthesis from China.

Woven polyester arterial prostheses have traditionally been known for their tight construction and smooth surface which has limited their healing capacity and resulted in poor attachment of their internal and external capsules. A new woven prototype has recently been developed in the Peoples' Republic of China. Among its unique features are its high physical porosity, softness and flexibility. This study undertook a series of in vitro tests to characterize its structure and physical properties in comparison with four commercial polyester grafts of North American origin. In addition, an animal trial was completed in which the new prototype was implanted as an infrarenal aortic substitute in 20 dogs for periods ranging from 4 h to 12 month. The in vitro tests confirmed a unique lightweight, highly porous, satin weave construction. Because of its high water permeability, preclotting was necessary before implantation. Once preclotted and installed, no significant blood loss was observed, and 19 of the 20 grafts remained patent at the sacrifice. Rapid full-width healing was achieved with tightly bound capsules, and more extensive tissue ingrowth was observed. Further work is needed to evaluate its long-term durability as an arterial substitute.

Nondestructive investigations on ninety-seven surgically excised mammary prostheses.

The information contained in the medical files of 68 patients having undergone surgical excision of a total of 97 internal mammary prostheses allowed us to define a typical patient profile at time of first implantation. Age: 33 years 11 months, height: 1.59 m, weight: 51.5 kg, two children. Twenty-one percent of these patients had the operation done subsequent to a mastectomy, while 79% requested it for cosmetic reasons. The duration of implantation was less than 55 months for 76% of the prostheses received after excision. The most frequent evolutive complications were the formation of a fibrous capsule followed by silicone bleeding, as well as mineralization. Macroscopic examination of the 97 explanted prostheses provided information on their integrity (38.1% of prostheses ruptured), gel differentiation (24.7%), sticky surfaces (26.8%), surface deposits (33%), memory folds (54.6%), and Dacron fixation patches (20.6%). According to the medical files, a fibrous capsule was found in association with 69.8% of the breast implants. We received only 46 capsules. The average thickness was 1.4 mm. Mineralizations were present on 15 capsules (32.6%). Two zinc phosphates were identified, for the first time, in human body: parascholzite and hopeïte. Statistical examination showed that Heyer-Schulte prostheses stayed in place for a longer time. Integrity and gel differentiation depended on the duration of the implantation. Presence of mineralization was model-related (Dow Corning prostheses were associated with deposits) and depended on the presence of fixation patches.

Collagen coatings as biological sealants for textile arterial prostheses.

Two collagen-coated grafts were studied: Hemashield (bovine collagen cross-linked with formaldehyde vapours and softened by exposure to glycerol) and Tascon (collagen fibres cross-linked with glutaraldehyde solution). The weight of the coating was 310 +/- 5 mg/g for Hemashield and 45 +/- 2.5 mg/g for Tascon. However, notwithstanding these differences, both coatings were efficient in making the walls of the grafts impervious to blood. The water permeabilities for the Hemashield and the Tascon were 8.7 and 5.9 ml.min-1.cm-2 at 120 mmHg respectively. The Hemashield collagen coating was rapidly eroded in vitro (4 h) after exposure to buffer, trypsin or pancreatin solutions, whereas the Tascon collagen coating remained well preserved after 7 d incubation. Both coatings were safe and did not interfere with the physical properties of the graft which was used as a skeleton. The healing properties of the Hemashield were similar to that observed with preclotted polyester prostheses, except in the early hours following graft implantation. On the other hand, the absence of erosion in the coating of the Tascon seemed to contribute to early antithrombogenicity. It also induced marked inflammatory reactions in the surrounding tissues and thus the healing appeared to be delayed.

First observation of hopeïte and parascholzite in fibrous capsules surrounding silicone breast implants.

We observed mineralization in 32.6% of the capsular tissue of 97 mammary prostheses recovered after surgical excision. Three distinct mineralogical phases were identified. The first was composed of common hydrated carbonate hydroxylapatite, a well-known physiological and pathological mineral. Hopeïte and parascholzite constituted the second and third phases. They are zinc and calcium hydrate phosphates that have not been observed previously in human tissues. Statistical analysis of the data showed relationships between the presence of mineralizations and the manufacturers on the one hand, and the presence of Dacron fixation patches at the surface of the prostheses on the other.

An arterial prosthesis from Argentina: the Barone Microvelour arterial graft.

The manufacture of a polyester vascular prosthesis in the southern hemisphere is a new development in the global dissemination of this maturing technology. Hence the recent introduction of the Barone Microvelour arterial graft from Argentina has highlighted the need for a comparative in vitro and in vivo study to compare its structure and performance with that of existing commercial products. Following a series of laboratory tests and implantations as a thoracoabdominal bypass in dogs, the Barone Microvelour has been identified as a strong graft constructed after the style of early weft-knitted designs. It provides an equivalent sequence and rate of healing to that of other polyester knitted grafts.

Characteristics of polyester arterial grafts coated with albumin: the role and importance of the cross-linking chemicals.

Preclotting is mandatory prior to implanting a knitted polyester arterial graft, unless the structure is made impermeable to blood by coating with a bioerodible material. Before achieving wide-spread clinical acceptance, the technique of impregnating with cross-linked albumin must be optimized in order to develop a graft that is immediately implantable, easy to handle and suture and has improved healing characteristics. The choice of the chemical to cross-link the albumin is of paramount importance. In this study two alternative candidates have been evaluated by using a series of tests to measure the physical properties, the morphology and the cytocompatibility of albumin-coated grafts. A carbodiimide cross-linking agent appears more promising than glutaraldehyde, since it is equally effective in producing a blood impermeable prosthesis, yet presents improved biocompatibility and provokes a less intense inflammatory response from the host.

In vitro and in vivo characterization of an impervious polyester arterial prosthesis: the Gelseal Triaxial graft.

Over the years, textile polyester arterial prostheses have acquired an excellent reputation for easy handling and good healing characteristics. Until recently, the main drawback in using them was the need for preclotting. This, however, is no longer true. Nonporous polyester grafts which have been coated with an impervious bioerodible layer during manufacture are now commercially available. The Gelseal Triaxial prosthesis is one of this new generation of grafts. It is manufactured by impregnating a Triaxial prosthesis with a gelatin coating. An in vivo and in vitro evaluation of this new device has found that its water permeability is almost zero. It has good handling and conformability characteristics, and its bursting strength is slightly greater than that of the uncoated prosthesis due, no doubt, to the presence of the gel. The rates of degradation of the gelatin coating have proven to be rapid under both in vitro and in vivo conditions. In fact, only a few traces of the gel were found remaining on the graft after 2 wk in the canine thoracic aorta. In addition, this study has demonstrated that the use of a bioerodible gelatin coating, with its ability to promote cellular regeneration, is a feasible approach with which to achieve earlier and more complete biological healing.

Per-operative uncontrollable bleeding at polyester (Dacron) arterial prosthesis implantation.

An aortobifemoral knitted polyester graft was placed in a 58-year-old woman with aorto-iliac occlusive disease. Although the prosthesis was preclotted in the usual manner, it never became impervious to blood under normal intra-arterial pressure. Examination of the graft showed lipid infiltration not ordinarily seen. We recommend that when a knitted prosthesis fails to preclot a woven graft should be used instead.

Physicochemical characterization of a hydrophilic microporous polyurethane vascular graft.

There is still a need for a viable small-diameter synthetic vascular graft. The expanded PTFE device appears to be the best presently available, but is still inferior to the autologous saphenous vein. Recently, a novel microporous, small-diameter vascular graft fabricated from Mitrathane, a polyether urethane urea (PEUU), has been developed. In this article, we report the findings of an in vitro evaluation of the morphological, mechanical, and chemical properties of this new device. The results are compared with those of established vascular prostheses made from alternative materials including expanded PTFE and bovine heterograft, and with natural blood vessels. The PEUU graft displays good mechanical properties in spite of the presence of some structural defects or anomalies. In particular it compares favorably to the expanded PTFE device by providing both superior radial compliance and improved suture tearing strength.

[Progressive complications associated with polyester arterial prostheses. Study of 61 specimens following surgical excision]. / Complications évolutives associées aux prothèses artérielles en polyester. Etude de 61 spécimens après exérèse chirurgicale.

Reports of individual surgical cases tend to be anecdotal because of the unique circumstances surrounding the patient, the surgeon, the intervention and, where applicable, the prosthetic device. To overcome this limitation the authors have taken a wider collaborative approach and report the analysis of 61 explanted polyester arterial prostheses associated with delayed complications on 53 patients reoperated upon in six different French hospitals. One advantage of such an independent and centralized retrieval programme is that the impact of centre specific factors, such as patient selection and surgical techniques, is minimized. Consequently, by following a standardized protocol for the evaluation of the morphologic, pathologic and mineralogic characteristics of the tissue surrounding the excised grafts, as well as the textile structure of the prostheses themselves, it has been possible to distinguish between iatrogenic and disease related complications and to demonstrate a number of general findings associated with the clinical performance of polyester arterial prostheses. Complications such as thromboses, infections and false aneurysms appear to occur randomly after different lengths of implantation, thicker fibrous tissue capsules are associated with velour grafts with highly textured yarns, the incidence of mineralized tissue and of endothelialized luminal surfaces is rare, weft knitted textile prostheses appear less mechanically stable and more sensitive to iatrogenic trauma than warp knitted, and the incidences of lipid and cholesterol adsorption, bacterial colonization and sterile fluid loss need further investigation. These observations lead to the recommendation that for patients with longer life expectancies surgeons should consider selecting low porosity, woven or warped knitted prostheses which contain yarns that have not been highly textured.

Textile arterial prostheses: is water permeability equivalent to porosity?

Porosity and water permeability are two distinct terms that describe different characteristics of vascular prostheses. The porosity is a measure of the void fraction within the prosthesis wall and is believed to give a rough prediction of the capacity of the graft to anchor newly formed surrounding tissue after implantation, whereas the water permeability indicates the rate at which water can flow through the prosthesis wall and, when measured under physiological pressure conditions, provides the surgeon with information about the need for preclotting prior to implantation. The literature has not always clearly distinguished between these two terms, and some authors in fact have suggested that they both refer to the same property of a prosthesis. In an attempt to clarify the issue, porosity and water permeability measurements were made on 34 commercial vascular prostheses having different textile constructions. Linear regression analysis demonstrated that these two characteristics are only weakly related (r = 0.59). It is therefore recommended that the current draft standards for such devices reference both properties: porosity and water permeability.

Albumin-coated polyester arterial prostheses: is xenogenic albumin safe?

This paper adds a new dimension to the series of studies concerned with the development of an albumin-coated polyester vascular prosthesis by addressing the question of the origin of the albumin. Previous experiments in dogs have used canine albumin-coated polyester arterial grafts. This study evaluated the biocompatibility of xenogenic material by implanting in dogs prostheses coated with bovine albumin and cross-linked with glutaraldehyde. Two series of albuminated grafts, one gamma radiation sterilized, the other ethylene oxide sterilized, as well as a preclotted control series were undertaken. The origin of the albumin did not appear to be significant. In fact, the healing pattern of the xenogenic albumin coated grafts was identical to that found previously with isogenic albumin. Nor did the method of sterilization produce significantly different pathological results. However, a slower rate of healing with the coated grafts compared to the preclotted controls did appear to be related to the slow rate of albumin erosion and the potentially cytotoxic effect of the glutaraldehyde cross-linking agent.

New polyester arterial prostheses from Great Britain: an in vitro and in vivo evaluation.

Two models of knitted velour polyester prostheses have been developed in Great Britain, i.e. the VP1200K and the VP50K Triaxial. The evaluation of these new devices in vitro and in vivo in dogs has demonstrated that, while the first model has similar surgical, mechanical and healing characteristics in the short term to other commercial knitted velour prostheses, the second model has lower water permeability and superior strength and dimensional stability. On the basis of these results, clinical investigations can be undertaken.