Function of rat skeletal muscles after storage at 10 degrees C in various preservation solutions

1. The purpose of this study was to assess the potential of various preservation solutions, orginally designed for solid organs, to protect muscle function during cold storage. 2. The soleus (SOL) and the cutaneous trunci (CT) muscle from the rat were isolated and stored for 2, 4 or 8 h at 10 degrees C. The solutions used, listed in order from an intracellular to an extracellular-like composition, were: University of Wisconsin (UW), Euro-Collins (EC), HTK-Bretschneider (HTK), reversed St. Thomas' Hospital (ST2) and Krebs-Henseleit (KH). After cold storage, the muscles were tested by direct electrical stimulation to obtain the maximum twitch tension (Pt) and the maximum tetanus tension (P0). Subsequently, the muscles were prepared for morphological analysis. 3. In general, storage at 10 degrees C caused a gradual decrease of Pt and P0 with time. After 8 h of storage in the extracellular-like solutions KH and ST2, the P0 was about 50% (SOL) and 35% (CT) of control. Eight hours of storage in intracellular-like solutions resulted in a P0 of 50% of control for HTK, in a P0 of 40% (SOL) and 67% (CT) for UW, but in a P0 of 5% (SOL) and 26% (CT) for EC. These findings corresponded well with the morphological observations. 4. It is concluded that the effects of 10 degrees C storage on skeletal muscle function are not predominantly determined by the intra- or extracellular-like composition of the solutions used. Both UW and HTK were most effective (P0 > 50% of control) in preserving muscle function.

Amount of hydroxyl radical on calcium-ion-implanted titanium and point of zero charge of constituent oxide of the surface-modified layer

To compare the surface properties of calcium-ion (Ca2+)-implanted titanium with those of titanium and to investigate the mechanism of bone conductivity of Ca2+-implanted titanium, amounts of hydroxyl radical of Ca2+-implanted titanium and titanium were estimated. Also, the point of zero charge (p.z.c.) of oxide constituting surface oxides of Ca2+-implanted titanium and titanium was determined. Results showed that the amount of active hydroxyl radical on Ca2+-implanted titanium was found to be significantly larger than that on titanium, indicating that the number of electric-charging sites of Ca2+-implanted titanium in electrolyte is more than that of titanium. The p.z.c. values of rutile (TiO2), anatase (TiO2), and perovskite (CaTiO3), were estimated to be 4.6, 5.9, and 8.1, respectively. Thus, Ca2+-implanted titanium surface is charged more positively in bioliquid than titanium, accelerating the adsorption of phosphate ions.

Reversed palmaris longus muscle causing effort-related median nerve compression

Two cases of effort-related distal median nerve compression in the dominant forearm caused by a reversed palmaris longus muscle are presented. Simple resection of the muscle belly was performed. Carpal tunnel release was done in one case, but in retrospect this was probably not necessary.

Effects of added antibiotics on the basic properties of anti-washout-type fast-setting calcium phosphate cement

The effect of added antibiotics on the basic properties of anti-washout-type fast-setting calcium phosphate cement (aw-FSCPC) was investigated in a preliminary evaluation of aw-FSCPC containing drugs. Flomoxef sodium was employed as the antibiotic and was incorporated into the powder-phase aw-FSCPC at up to 10%. The setting time, consistency, wet diametral tensile strength (DTS) value, and porosity were measured for aw-FSCPC containing various amounts of flomoxef sodium. X-ray diffraction (XRD) analysis was also conducted for the identification of products. To evaluate the drug-release profile, set aw-FSCPC was immersed in saline and the released flomoxef sodium was determined at regular intervals. The spread area of the cement paste as an index of consistency of the cement increased progressively with the addition of flomoxef sodium, and it doubled when the aw-FSCPC contained 8% flomoxef sodium. In contrast, the wet DTS value decreased with increase in flomoxef sodium content. Bulk density measurement and scanning electron microscopic observation revealed that the set mass was more porous with the amount of flomoxef sodium contained in the aw-FSCPC. The XRD analysis revealed that formation of hydroxyapatite (HAP) from aw-FSCPC was reduced even after 24 h, when the aw-FSCPC contained flomoxef sodium at > or = 6%. Therefore, the decrease of wet DTS value was thought to be partly the result of the increased porosity and inhibition of HAP formation in aw-FSCPC containing large amounts of flomoxef sodium. The flomoxef sodium release from aw-FSCPC showed the typical profile observed in a skeleton-type drug delivery system (DDS). The rate of drug release from aw-FSCPC can be controlled by changing the concentration of sodium alginate. Although flomoxef sodium addition has certain disadvantageous effects on the basic properties of aw-FSCPC, we conclude that aw-FSCPC is a good candidate for potential use as a DDS carrier that may be useful in surgical operations.

Tissue response to fast-setting calcium phosphate cement in bone

Fast-setting calcium phosphate cement (FSCPC) is a promising new bioactive cement with a significantly short setting time (approximately 5-6 min) compared to conventional calcium phosphate cement (c-CPC) (30-60 min) at physiologic temperatures. As a result of its ability to set quickly, it is applicable in surgical procedures where fast setting is required. In this study, FSCPC was implanted in rat tibiae to evaluate tissue response and biocompatibility. FSCPC was converted to hydroxyapatite (HAP) in bone faster than c-CPC in the first 6 h. By 24 h, significant amounts of both FSCPC and c-CPC had been converted to HAP. The conversion of FSCPC into HAP further proceeded gradually, reaching 100% within 8 weeks. Infrared spectroscopic analysis disclosed the deposition of B-type carbonate apatite, which is a biological apatite contained in human dentin or bone, on the surface of the FSCPC. Histologically, FSCPC showed a tissue response similar to that of c-CPC. A slight inflammatory reaction was observed in the soft tissue apposed to both cements in the early period, and new bone was formed along the surface of the FSCPC at the adjacent bone. However, no resorption of either cement by osteoclasts or macrophages was observed within 8 weeks. We conclude that FSCPC is superior to c-CPC in clinical applications in oral and maxillofacial, orthopedic, plastic, and reconstructive surgery, since it shows a faster setting time and higher mechanical strength in the early period that are required in these surgical procedures, as well as osteoconductivity and excellent biocompatibility similar to that of c-CPC.

Influence of modification of Na2O in a glass matrix on the strength of leucite-containing porcelains

The desirable thermal properties of matrix glass to the strength of feldspar porcelain with leucite crystal were investigated. Five kinds of feldspar glasses, each with different a content of Na2O, were prepared for the matrix glasses of the leucite-containing porcelains. The specimens were arranged by mixing each glass powder with high-purity natural leucite crystals (0, 20 and 40%) followed by firing. The thermal properties of the glass and the transformation temperature of the leucite were measured. A three-point bending test was performed to measure the flexural strength of the porcelains. The glass transition temperature and deformation temperature of the glass-only porcelains were decreased as the Na2O content increased. The Na2O-modified glasses were substantially strengthened by the leucite dispersion. However, the strength of the porcelains was affected by the relation between the transformation temperature of the leucite and the thermal properties of the glass matrix. It was concluded that control of the residual stress in the composite porcelain is an important factor in developing high strength porcelain containing leucite.

Non-decay type fast-setting calcium phosphate cement: hydroxyapatite putty containing an increased amount of sodium alginate

A hydroxyapatite [(HAP) Ca10(PO4)6(OH)2] putty that behaves like a putty or self-curing resin was made by increasing the amount of sodium alginate in non-decay type fast-setting calcium phosphate cement (nd-FSCPC). nd-FSCPC became viscous as the sodium alginate concentration was increased. The best handling properties were obtained when nd-FSCPC contained 8% sodium alginate in its liquid phase. When a 2-kg glass plate was placed on the paste, HAP putty spread to form an area three times that of FSCPC paste. Thus, HAP putty is expected to be easier to use than FSCPC in the filling of bone defects. HAP putty did not decay; in fact, it set within approximately 20 min when immersed in distilled water immediately after mixing. The wet diametral tensile strength value of HAP putty was approximately 12 MPa after 24 h, the same as that for nd-FSCPC containing 0.5% sodium alginate in its liquid phase, or FSCPC that is free from sodium alginate. The elements constituting set HAP putty were examined using powder X-ray diffraction and found to be predominantly apatitic minerals after 24 h. Since the handling properties of a putty or self-curing resin-like cement are very useful in certain surgical procedures, HAP putty made by increasing the sodium alginate concentration in nd-FSCPC is potentially a valuable new biomaterial for use in plastic and reconstructive surgery, as well as oral and maxillofacial surgery.

The role of suture material in hypertrophic scar formation: Monocryl vs. Vicryl-rapide

The development of hypertrophic scars and keloids is an unsolved problem in the process of wound healing. There are indications that inflammation plays an important role in this process, but its exact mechanism remains unclear. In this study the amount of inflammation and the development of hypertrophic scars and keloids was investigated in inframammary skin incisions sutured with synthetic absorbable suture materials: a monofilamentous suture (Monocryl) compared with a multifilamentous suture (Vicryl-rapide). In 81 breast reduction patients Monocryl (N = 28) has proved to give significantly smaller, less reactive scars with a lower tendency toward hypertrophic scar formation compared with Vicryl-rapide (N = 53).

Review of facilitated approaches to vascular anastomosis surgery

BACKGROUND

There is an increasing demand for an easier, quicker, less damaging, but reliable procedure to create a vascular anastomosis. This demand is not new but is revitalized by the movement of vascular procedures in various specialties, including cardiac surgery, toward minimally invasive procedures. This article reviews the most important representatives of devices or methods that have been developed in the last two centuries.

METHODS

A thorough literature search was performed. The outcome is presented and discussed in four parts: (1) stapling and clipping devices, (2) coupling devices, (3) glues, and (4) laser welding.

RESULTS

Stapling devices have not become the standard fashion to create an anastomosis because they are too complicated to use. In selected cases clips have potential in vascular surgery. There is a ring-pin coupling system available that is easy to use and especially suitable for creating an end-to-end anastomosis. The ideal glue is yet to be developed, and the currently available laser welding techniques have to become refined.

CONCLUSIONS

It is anticipated that the future lies in hybrid techniques that combine sutures or clips with glues or laser-welding techniques.

Adventitial stripping does not strip the adventitia

This study investigates the process of stripping the adventitia off a blood vessel, which is a normal procedure prior to performing a microvascular anastomosis. In five rats, the common carotid and the superficial femoral arteries of one side were stripped sharply, whereas the arteries of the other side were left unstripped to serve as controls. In a further set of five rats, the arteries were stripped bluntly. Immediately following stripping, experimental and control arterial segments were removed. Histology of cross sections of the segments was studied. In no case was there complete removal of the adventitia. When stripped and control arterial sections were compared, no significant difference between cross-sectional adventitial areas could be demonstrated. Morphologic study revealed that stripping mainly removes large collagen fibers from the adventitia. The small collagen fibrils that are still in place fan out in such a way that although considerable tissue is removed, the volume that the adventitia occupies remains the same. Stripping the adventitia does not cause complete removal of the adventitia, and in this study no significant reduction in the adventitial volume could be found. Stripping does, however, allow a better view of the cut edge of the vessel wall under an operating microscope. Since blunt stripping could cause damage to other vessel wall layers, sharp stripping is to be preferred.

[Iatrogenic cicatricial endometriosis]

A woman aged 36, who two years previously had undergone a caesarean section, developed a painful swelling of the scar attributed to cicatricial endometriosis. This is a rare disorder brought about by peroperative displacement of normally or ectopically situated uterine mucous membrane to the surgical wound. There, it may proliferate and cause characteristic signs and symptoms that are simple to diagnose: cyclic pain, swellings and sometimes, bleedings. Pharmaceutical, possible hormonal treatment is of limited value, because cessation of the medication is frequently followed by recurrences. Consequently, ample surgical excision in endometriosis is to be preferred; this is to be regarded as a curative therapy.

Surface modifications of titanium in calcium-ion-containing solutions

The surface of titanium was modified in calcium-ion-containing solutions to improve bone conductivity. Three kinds of aqueous solutions for the modification were prepared using calcium nitrate, calcium chloride, and calcium oxide. The pH values of the solutions were 3.9, 7.4, and 12.6, respectively. At first, anatase powder was immersed in the solutions of 7 days to confirm the effect of the solutions on the modification. As a result, calcium titanate was formed on the anatase powder, indicating that the titanium surface was possibly modified by the solutions. Titanium plates were then immersed in the solutions at ambient temperature for 7 days, washed by deionized water, and dried. X-ray photo-electron spectroscopy of surface-modified titanium revealed that the surface-modified layer contained calcium hydroxide and/or calcium titanate. The surface-modified layer in which titanium was modified was thickest in this order: calcium oxide, calcium chloride, and calcium nitrate solutions. Apatite was formed on the surface-modified titanium in Hanks' solution while apatite was undetected on unmodified titanium. Therefore, the surface modification of titanium may improve bone conductivity. The amount of apatite corresponded to the thickness of the surface-modified layer and the amount of calcium in the layer.

Effect of barium in porcelain on bonding strength of titanium-porcelain system

The bonding strength to titanium, thermal expansion, and bending strength of glassy porcelain containing barium of 5, 10, and 15 mass% were estimated and compared with those of barium-free porcelain, to estimate the effect of barium content on bonding strength to titanium. The three different glassy porcelains containing barium were made by melting at 950 degrees C. The bonding strength of a commercial porcelain to titanium increased with the addition of barium. Bending strength and thermal expansion were not affected by the barium content. Therefore, the addition of barium to porcelain is effective for strengthening the bonding of porcelain to titanium.

Auricular hypermobility due to agenesis of the extrinsic muscles

A patient is presented with complaints of a hypermobile right ear due to agenesis of the superior and posterior auricularis muscles and a thin concha cartilage. Suturing the concha cartilage to the mastoid bone and temporal fascia gave sufficient support of the external ear without creating a gross difference in appearance of both ears.

Non-decay type fast-setting calcium phosphate cement: setting behaviour in calf serum and its tissue response

Non-decay type fast-setting calcium phosphate cement (nd-FSCPC) was evaluated in terms of its setting behaviour in calf serum and its tissue response to investigate the feasibility of its clinical use in surgical applications. Non-decay type cements were prepared by adding various amounts of sodium alginate to the liquid phase of base cements, fast-setting calcium phosphate cement (FSCPC) and conventional calcium phosphate cement (c-CPC). Cement pastes were immersed in serum at 37 degrees C immediately after mixing, and decay behaviour, setting time and mechanical strength were measured to evaluate the possibility of their use in surgical applications. Also, nd-FSCPC was implanted into rat subcutaneous tissue for the initial evaluation of biocompatibility of this potential bioactive cement. nd-FSCPC set in approximately 6-7 min in serum, even when the cement paste was immersed in the serum immediately after mixing, whereas c-CPC and FSCPC decayed completely upon immersion. nd-FSCPC transforms to hydroxyapatite (HA) within 24 h and shows a diametral tensile strength of approximately 4-5 MPa. As a result of transformation to HA, nd-FSCPC showed excellent tissue response when implanted subcutaneously in rats. We conclude that nd-FSCPC has good potential value for use in orthopaedics, plastic and reconstructive surgery, and oral and maxillofacial surgery, where the cement is exposed to blood.

Fascia lata suspension of malpositioned ears

A new technique for the correction of malpositioned ears in congenital or acquired disorders is described. The use of a fascia lata strip makes a rigid fixation of the ear to the pericranium possible without total fixation of the ear in all directions. The configuration of the auricle is not altered, and the scars are inconspicuous.

Dysfunctional postures of the hand as part of a conversion reaction

A dysfunctional posture of the hand could be due to an anatomical disorder or a conversion reaction. A conversion reaction implies that an unconscious intrapsychic conflict is expressed in a physical dysfunction. Treatment of dysfunctional postures due to conversion reactions is often difficult, and case reports are used to outline management. The need for a multidisciplinary approach is stressed.

Correction of severe blepharoptosis

An analysis is made of 81 patients with severe blepharoptosis who underwent correction with autogenous fascia. In case of severe blepharoptosis, which means a levator function of less than 5 mm, correction by levator resection gives insufficient results. Better results are obtained by frontalis suspension, whereby the upper eyelid is connected to the frontalis muscle using fascia lata strips according to Crawford. The operative technique is described in detail. Particular interest has been paid to the width of the vertical lid fissure and symmetry between both upper eyelids after operation. The overall results were rated satisfactory to excellent with an average of 9 mm of postoperative vertical lid fissure. Comparison of the results of unilateral versus bilateral blepharoptosis correction revealed better results in the group of bilateral ptosis correction. In 76% of the bilateral patients, there was an asymmetry of less than 0.5 mm between both palpebral fissures, while in the unilateral group this result was achieved in only 35% of the cases. Symmetry is difficult to achieve in the unilateral group, especially when the vertical lid fissure of the nonptotic eye is 10 mm or more. In these cases, correction of both upper eyelids should be considered. The best time to operate on patients with severe congenital blepharoptosis is around the age of 4 to 5 years, because lagophthalmus after operation is better tolerated and the leg has developed sufficiently to provide an adequate amount of fascia. The correction of severe blepharoptosis by frontalis suspension with autogenous fascia shows a high rate of success and few complications.

Camptodactyly caused by an anomalous origin of the flexor digitorum superficialis tendon. Case Report

A 20 year old man with a progressive flexion contracture of the proximal interphalangeal joint of his right ring finger had an anomalous origin of the flexor digitorum superficialis tendon. After excision of the aberrant flexor tendon the patient had a normal range of movement of the proximal interphalangeal joint.

Oxidative processes and free radical scavengers in ischaemia-reperfusion injury in adipocutaneous flaps: in vitro lipid peroxidation assessment

An in vitro lipid peroxidation study measuring Schiff base and TBAR formation in homogenates of the fat and skin fractions of epigastric free flaps of DA-rats was performed to determine the role of oxygen-derived free radicals (ODFRs) in the aetiology of ischaemic injury and of ischaemia and reperfusion injury following cold (0-1 degree C) storage. The storage intervals were 0, 48, 72, 96 and 120 h in the study on ischaemic injury and 72 and 96 h in the study on combined ischaemia and reperfusion injury. Reperfusion was accomplished by anastomosing the pedicle vessels of the flap to the femoral vessels of a recipient; the reperfusion period was 15 min. In addition to a control group (C), three experimental groups were created to test the benefit of a preischaemic single passage perfusion with a hypertonic citrate solution (HCA), a pre- and postischaemic treatment with desferrioxamine (DFX) and a pre- and postischaemic treatment with lipoic acid (LA). The susceptibility of homogenates of skin and fat fractions of epigastric free flaps in DA-rats for lipid peroxidation increased significantly whenever the cold (0-1 degree C) ischaemic interval was prolonged from 0 to 72 h. These findings offer circumstantial evidence for the role of ODFRs in the aetiology of ischaemic injury. Following a short reperfusion period after extended periods of cold (0-1 degree C) ischaemia, no significant increase in susceptibility for lipid peroxidation could be found. Furthermore, no unequivocal role in the prevention of ischaemia and/or reperfusion injury by the use of either HCA, or DFX or LA could be found. The exact role of ODFRs in the aetiology of ischaemia-reperfusion injury in this setting remains unclear.

Thigh augmentation

Based on the experience with calf and buttock augmentation, a new type of implant was designed for thigh augmentation. A case report is presented.

In vivo setting behaviour of fast-setting calcium phosphate cement

The in vivo setting behaviour of fast-setting calcium phosphate cement (FSCPC) between femoral muscles of the rat was investigated to evaluate the possible value of FSCPC for medical and dental application. Conventional CPC (c-CPC) and FSCPC were implanted between femoral muscles, and various aspects of the setting behaviour such as setting time, mechanical strength and conversion ratio of cement into hydroxyapatite (HAP: Ca10(PO4)6(OH)2) were measured by the Vicat needle method, diametral tensile strength (DTS) measurement, and quantitative powder X-ray diffraction (XRD) analysis, respectively. The setting time of FSCPC in vivo was 5-7 min, in contrast to 48 min for c-CPC. As a result of its fast setting, set specimens of FSCPC showed higher mechanical strength from the initial stage than c-CPC. Higher DTS values were observed in FSCPC than c-CPC implanted after 24 h. Powder XRD analysis revealed faster conversion of FSCPC than c-CPC into HAP, which was responsible both for the faster setting and higher mechanical strength from the initial stage. We concluded, therefore, that FSCPC may be used for a wide range of clinical applications, i.e. fields where fast setting is required such as orthopaedic, plastic and reconstructive, and oral and maxillofacial surgery.

Development of calcium phosphate based functional gradient bioceramics

A functional gradient bioceramic that can function gradually with respect to body tissue was studied by changing the composition of calcium phosphate gradually from the surface to the inside. Diamond powder was spread on the surface of compact hydroxyapatite (HA) powder and fired at 1280 degrees C under reduced pressure, followed by firing under atmospheric conditions. The sintered body thus prepared was dense and alpha-tricalcium phosphate (alpha-TCP: alpha-Ca3(PO4)2) was found on its surface. The content of alpha-TCP gradually decreased with increasing depth from the surface. In contrast, the content of HA increased with increasing depth from the surface. The gradient ratio of alpha-TCP and HA depends on the firing time for each condition, i.e. reduced or atmospheric pressure. The alpha-TCP formation was ascribed to the decomposition of HA due to the spontaneous combustion of diamond powder.

Non-decay type fast-setting calcium phosphate cement: composite with sodium alginate

Non-decay type fast-setting calcium phosphate cement (nd-FSCPC) was prepared by introducing sodium alginate (0-2.0 wt%) into the liquid phase of FSCPC. nd-FSCPC was stable even when the cement paste was immersed in distilled water immediately after mixing, whereas conventional FSCPC (c-FSCPC) decayed completely within 1 min upon immersion. The setting time of the cement, approximately 5 min, was not dependent on the presence of sodium alginate. In contrast, the introduction of sodium alginate into conventional CPC, i.e. CPC without neutral phosphate in the liquid phase, resulted in no setting when the amount of sodium alginate introduced was more than 1 wt%. Powder X-ray diffraction analysis revealed no significant difference for the conversion of cement to apatite for any concentrations of sodium alginate studied (0-2.0 wt%). The mechanical strength of the cement increased rapidly with the addition of sodium alginate up to 0.8 wt% when the cement paste was immersed and kept in distilled water at 37 degrees C, whereas further addition of sodium alginate decreased the mechanical strength. The results obtained in this investigation, taken together with sodium alginate's known excellent biocompatibility and absorption behaviour, indicate that the use of sodium alginate composite FSCPC as nd-FSCPC should be of value in orthodontics and oral and maxillofacial surgery where the cement is exposed to blood.

A histological study of cutaneous thermal wounds using a Clostridium perfringens-derived wound healing substance with wound healing stimulation activity

We studied the effects of a Clostridium perfringens-derived wound-healing substance (WHS) on the healing of thermal burn wounds. Third-degree burn injuries were inflicted on the back skin of rats. We histologically evaluated the effects of WHS ointments and compared them with those of lysozyme chloride ointment. We observed the formation of dermal collagen fibers and the increase of capillaries in the WHS ointment treated groups. From the results of hematoxylin and eosin staining and silver staining, an increase in capillaries was observed one week after the application of WHS ointment. Three weeks after the application, when the epithelization was in the final stage, capillary formation ceased. In the WHS ointment-applied groups, electron microscopic observation showed that new collagen fibers were regularly formed in the dermis. On the other hand, in the lysozyme chloride ointment-applied groups, new collagen fibers were present, but were irregularly formed. The main wound healing stimulative action of the WHS ointment could be due to its acceleration of new capillary formation.

Effect of leucite crystals on the strength of glassy porcelain

Porcelains with leucite crystals dispersed into various glass matrices were prepared for investigating the effects of the leucite crystals on the mechanical strength of glassy porcelain. The strength of glassy porcelains containing leucite crystals was affected by the differences of thermal expansion coefficients, compositions and deformation temperatures of the glass matrices. In the case of a large mismatch of thermal expansion between the leucite crystals and boro-silicate glass, the strength decreased with increasing amount of leucite. In leucite porcelains using a feldspar glass matrix, there was little or no effect of leucite on the strength. However, the strength of porcelains consisting of leucite crystals and a soda-lime glass matrix was enhanced with increasing leucite content, compared with that of the glassy matrix alone. Such an increase in strength is considered to be because the interface between the glassy matrix and leucite particles occurred in continuous phases, with an effect due to fusion occurring during the transition from leucite particles to the glass phase.

Diffusion of elements in porcelain into titanium oxide

The diffusion of elements of commercial porcelain for titanium into titanium oxide during heating was investigated. Titanium was deposited on three kinds of disk-shaped porcelains by vacuum-vaporization and the porcelains were then heated. A thin titanium oxide film was formed on the porcelains by the heating. X-ray photoelectron spectroscopy was used to characterize the surfaces of the porcelains with and without titanium oxide. Only sodium, potassium, and barium diffused into titanium oxide during heating, where they formed a complex oxide with titanium. The diffusion of these elements may be involved in the bonding of porcelain to titanium.

Shock-absorbing behavior of four processed soft denture liners

The cushioning effect of soft denture liners was evaluated with the use of a free drop test with an accelerometer. The materials tested included SuperSoft, Kurepeet-Dough, Molteno Soft, and Molloplast-B brands. All materials were found to reduce the impact force when compared with denture base resin. A 2.4 mm layer of soft denture material demonstrated good shock absorption. The Molloplast-B and Molteno Soft materials showed excellent shock absorption. When the soft denture liner was stored in distilled water for 180 days, the damping effect recorded for all materials tested was increased. The aging of all materials also affected the cushioning effect.

Effect of crystallization on fracture strength of castable glass-ceramics containing two crystals

The relationship between fracture strength and crystallization in castable glass-ceramics was studied using castable glass-ceramics which contained crystalline apatite and magnesium titanate. Bending strength was increased with increases in crystal phases; 90, 124, 122 and 162 MPa were recorded for as-cast specimens and specimens cerammed at temperatures of 905 degrees, 925 degrees and 945 degrees C, respectively. The results of bending tests suggest that the crystallization of magnesium titanate is more effective than that of apatite in increasing the strength of glass-ceramics. Fracture toughness in specimens reheated at 905 degrees C was doubled compared with as-cast specimens. The apatite particles precipitated during ceramming treatment were thought to be an important factor in increasing both the fracture toughness and crack pinning effect.

Cold (0 degree C) ischaemic tolerance of latissimus dorsi free flaps in rats: a macroscopic and morphological study

The purpose of this study was to define the cold (0 degree C) ischaemic tolerance (CIT) of the latissimus dorsi free flap in inbred rats. Flaps were isolated, stored at 0 degree C for periods of time ranging from 0 to 120 hr and then revascularised and reperfused for 14 days. Thereafter the CIT was assessed macroscopically, and by light microscopy. Electron microscopy was performed in flaps after 0 and 24 hr of reperfusion following a cold ischaemic interval ranging from 0 to 120 hr. From this preliminary study, it was concluded that the CIT was 48-72 hr.

Effect of adding diamond particles on the fracture toughness of apatite ceramics

Composite ceramics dispersed through diamond particles with hydroxyapatite as a matrix were prepared by firing at 1250 degrees C under reduced pressure or normal atmosphere. The fracture toughness and physical properties of sintered composite ceramics were examined to determine methods of strengthening hydroxyapatite ceramics. The diamond crystal in composite ceramics was transformed to graphite by firing and the fracture toughness of hydroxyapatite ceramics increased with diamond addition. At 10 wt% diamond, the maximum value for fracture toughness was obtained, and the further addition of diamond particles over 10 wt% caused fracture toughness to decrease. Such increases in fracture toughness were considered the result of microcracking which occurred during the transformation from diamond to graphite.

The benefit of a single-passage perfusion with a hypertonic citrate solution on the cold ischemia tolerance of epigastric free flaps in Dark-Agouty rats

In this study the effectiveness of a single-passage perfusion with hypertonic citrate solution on the cold ischemia tolerance in epigastric free flaps in Dark-Agouty rats was investigated. In the control group a significant decline in survival percentage was observed when the storage time was extended from 72 hours to 96 hours. A single (pressure controlled) passage perfusion with hypertonic citrate solution was able to prevent this decline.

Non-revascularized epigastric free flap: no all-or-none survival pattern

We have previously shown that the epigastric flap in Dark Agouty rats, measuring approximately 6 x 4 cm with borders related to well-defined anatomical structures, does not exhibit an all-or-none survival pattern. This study was designed to investigate the survival pattern of non-revascularized epigastric flaps in three other rat strains (Sprague-Dawley, Brown-Norway, and Lewis). In concordance with our earlier observations, but in contrast to reports by many other groups, in none of the used strains was an all-or-none survival pattern observed. Survival varying from 2 to 30% (mean, 12%) of the original flap, without significant differences between the strains, was found. The locations of survival exhibited a clear pattern, probably owing to the fat pad in the subcutis and revascularisation from the recipient wound edges.

Neither desferrioxamine nor lipoic acid enhances the cold ischaemic tolerance of epigastric free flaps in rats

This study was designed to test the ability of pre- and postischaemic administration of desferrioxamine (DFX), a combination of a preischaemic single passage perfusion with hypertonic citrate solution (HCA) and postischaemic administration of DFX, and pre- and postischaemic administration of lipoic acid (LA) to enhance the cold (0 degree C) ischaemia tolerance in epigastric free flaps in inbred rats. The ischaemic intervals varied between 0 and 120 hr. The area of flap survival 2 weeks after revascularisation as a percentage of original flap size was recorded as an exponent of ischaemic tolerance. None of the treatment regimens was able to increase flap area survival. Histologically, there were no major differences between the different treatment regimens.

Cutaneous trunci myocutaneous flap: a new and reliable model for muscle free flap research in the rat

This paper deals with the first myocutaneous flap in the rat. It is located just caudal to the axilla and consists of the insertion of the cutaneous trunci muscle with overlying subcuticular fat and skin and is supplied by the lateral thoracic vessels. It exhibits an all-or-none survival pattern. Because the skin can serve as a marker for muscle viability, we believe that this flap has great potential in future free muscle research.

Survival characteristics of the epigastric free flap in DA-rats

Epigastic flaps measuring approximately 6 x 4 cm with borders related to well-defined anatomical structures were isografted (Dark Agouty to Dark Agouty inbred rats) with or without anastomosing their epigastric pedicle, after various periods of ischaemia, ranging from 0 to 120 h. During the ischaemic insult the flaps were stored at 0 degrees C in a hypertonic citrate solution. The non-revascularized flaps exhibited survival percentages varying from 2 to 34% (mean, 16%) of the original flap,. independent of the storage interval. The flaps that were revascularized after ischaemia had a 100% survival when transplanted immediately after isolation and following 48 h of cold storage. Mean survival percentages of 78% after 72 h of ischaemia, 32% after 96 h, and 4% after 120 h of ischaemia were found. It is concluded that the model described in this study is suitable for free flap research, because of its delineated borders. However, when the area of flap survival is lower than 30% in revascularized flaps there is a distinct likelihood that the flaps have survived regardless of the pedicle as simple Wolfe or composite grafts. Results must therefore be interpreted with great care.

[Deformities due to finger sucking]

Finger sucking can result in deformities of the fingers as well as the deformities well-known in orthodontics. Besides skin changes resulting from chronic irritation, more serious deformities in position or function of the fingers appear to occur. In these cases it is mostly the index finger that is affected. Upon ceasure of the habit the skin changes prove to be reversible; the deformities in position and function of the fingers however do not always display spontaneous improvement. A review of relevant literature and an account of two patients with characteristic case histories is given.

[Clinical evaluation of intra-arterial infusion of hyperthermo-chemotherapy in gastric cancer]

We performed intra-arterial infusion hyperthermochemotherapy by retaining an intra-arterial reservoir in 17 lesions of 12 patients with non-resectable, metastatic or recurrent gastric cancers. The 12 patients consisted of one with a primary gastric cancer lesion, 6 with a solitary gastric cancer lesion metastasizing to the liver, 4 with gastric cancer accompanied by hepatic metastasis, lymph node metastasis or local recurrence, and one with a gastric cancer lesion metastasizing to Douglas' pouch. A catheter was retained in the hepatic artery of all 6 patients with a solitary gastric cancer lesion metastasizing to the liver, and a catheter was retained in the aorta of the patient with a primary lesion, 3 of the 4 patients with two or more metastatic lesions, and the patient with a lesion metastasizing to Douglas' pouch. The duration of each hyperthermia session was 50 minutes, and one or two sessions were performed within a week. One course consisting of 5 or 6 sessions was repeated. Antineoplastic drugs such as MMC, 5-FU, ADR, epi-ADR, CDDP and VP-16 were injected in bolus form or administered serially through the reservoir. Nine of the 12 patients had polypharmacy. One to 3 courses or 4 to 20 sessions at maximum (average 9.8 sessions) were given. The rate of efficacy of intra-arterial infusion hyperthermochemotherapy was 44% for hepatic metastasis and 25% for lymph node metastasis. The local recurrent lesions, the lesion metastasizing to Douglas' pouch and the primary lesion did not respond to therapy.

Firework injuries to the hand

Hand injuries by fireworks occur every year especially around New Year's Eve. These complex injuries show a combination of avulsion, laceration, blast, crush and burns. Three typical cases are presented and their treatment is outlined.

Geometrical approach to the end-to-side anastomosis

We analyzed the procedure of performing an arterio- or venotomy in rats and changed it from parallel to the long axis to perpendicular to the long axis. Simultaneously, geometrical analysis of the shape of an arterio- or venotomy led to a new approach for the end-to-side anastomosis in experimental free flap transplantation. This new method was applied in 268 anastomoses. It necessitated only six sutures and resulted in 100% arterial early and late patency and in 99% venous early and late patency.

Viscosity of dental porcelains in glass transition range

Changes in the viscosity of dental porcelain as a function of temperature are the controlling factor determining incompatible stresses in porcelain-fused-to-metal restorations. A new method was used to estimate viscosity using a viscoelastic analytical model that considers the relation between the heating rate and deformation temperature (Td) of dental porcelain with stress applied during heating. The activation energy of viscous flow and the viscous constant in the Arrhenius equation were calculated for six kinds of commercial body and opaque porcelains. The effect of the heating rate on the instantaneous coefficient of thermal expansion was also measured. Tg onset was graphically determined using data on thermal deformation and agreed well with the strain point as defined by viscosity. The data gathered in this study was also compared to the experimental results of previous works by others.

Effects of zirconia addition on fracture toughness and bending strength of dental porcelains

Zirconia dispersed composite porcelains with glass and aluminous porcelain as matrix were prepared as models of dental porcelains. The bending strength and fracture toughness of the composite porcelains were examined. The bending strength and fracture toughness of composite porcelains containing 50 wt% zirconia were 20 to 80% greater than in glass alone. However, bending strength and fracture toughness decreased upon the addition of zirconia at more than 50 wt%. Moreover, in the case of aluminous porcelain as matrix, fracture toughness increased to a maximum value of 2.6 M Pa.m1/2by addition of 23 wt% zirconia, twice the toughness of glass alone. On the other hand, no increase of bending strength was observed in this case. Deflection and bowing of cracks as well as microcracking effects were related to these increases of mechanical properties in zirconia dispersed composite porcelains.