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Biomedical subjects

L Salemark

Publications and source records attributed to L Salemark.

35 records · Page 2Linked to original sources
PubMed1995

Mandibular reconstruction by secondary reimplantation of resected segments: a preliminary report.

This paper presents a new method of reconstructing the mandible after ablative surgery for cancer. This method uses autogenous grafts consisting of the respected part of the mandible, which is hollowed out, defatted in chloroform/methanol, sterilized with ethylene oxide, irradiated with beta-radiation (dose 25 kGy), and stored for 7-10 months. At reimplantation, they were filled with compressed, autogenous, particulate cancellous bone. All grafts took, and four of six host-graft junctions healed.

Aged↗
PubMed1994

Platelet accumulation and thrombus formation after microarterial injury. An experimental study in rabbits.

Patency rats and accumulation of 32P-labelled platelets were studied in the central ear arteries of rabbits (which were not treated with antithrombotic agents) after three types of vascular injury: End to end anastomosis, arteriotomy and superficial injury to the vessel wall to expose the lamina elastica interna/juxtaluminal parts of the tunica media, arteriotomy and deep injury to the vessel wall to expose the deeper layers of the tunica media. The superficial and deep vessel injuries were 5 mm long. Patency rates were 100% after end to end anastomosis and superficial injury, and 48% after deep injury. In a separate group of vessels with deep injuries the time course of formation of occlusive thrombi was investigated: occlusion was already present 15 minutes after reperfusion in all but one of seven occluded vessels. Platelet accumulation ratios were significantly higher after deep injury than after end to end anastomosis or superficial injury. In deeply injured patent vessels, platelet accumulation reached a maximum after about 30 minutes, which was later followed by a gradual decrease. Platelet accumulation patterns indicating sustained thrombogenicity throughout the measurement interval (embolization/reaccumulation patterns or late increases in accumulation) were encountered in only three of 22 deeply injured vessels. We conclude that: to cause formation of occlusive thrombus in otherwise healthy arteries and animals, a deep injury to the tunica media is necessary, and following reperfusion after repair of damaged vessels the time course of the thrombotic challenge is short.

Anastomosis, Surgical↗
PubMed1994

Effects of streptokinase and urokinase on microarterial thrombosis and haemostasis. An experimental study in rabbits.

The effects of streptokinase and urokinase on haemostasis, accumulation of platelets radiolabelled with phosphorus (32P) and patency were studied after arteriotomy and deep vessel wall trauma of the central arteries of rabbits' ears. In one study, 12 rabbits were given 1700 IU/kg body weight of streptokinase or urokinase as intraaortic bolus injections five minutes before vascular reperfusion (opening of vascular clamps). A further six were given saline (controls). In the second, 12 further rabbits were each given 3,400 IU/kg of either substance, one fifth as a bolus before reperfusion and the remainder as a continuous infusion during the next two hours. A further six were given saline (controls). Irrespective of the dosage regimens, neither substance improved patency compared with saline-treated controls. Separate dose response studies with streptokinase showed that bolus or bolus+infusion doses larger than those given caused troublesome arteriotomy bleeding. Compared with controls, streptokinase increased, and urokinase decreased, accumulation of platelets. This was not reflected in differences in patency rates, which were similar in all groups. In conclusion, fibrinolytic stimulation with non-thrombolytic doses of streptokinase or urokinase did not prevent microarterial thrombosis in rabbits. The therapeutic index for these substances in clinical microvascular surgery is probably low, as haemorrhagic complications may be expected.

Animals↗
PubMed1992

Clonal structural chromosome aberrations in nonneoplastic cells of the skin and upper aerodigestive tract.

Cytogenetic analyses of tumors of the skin and upper aerodigestive tract have repeatedly revealed small, pseudodiploid clones characterized by balanced structural rearrangements and a high frequency of cells with nonclonal structural aberrations. However, the lack of common cytogenetic denominators within the different histologic subtypes, the discrepancy between cytogenetic findings and data obtained from flow cytometric DNA content studies, and the occasional identification of tumors with massively rearranged karyotypes indicate that the chromosome rearrangements present in pseudodiploid cells have little to do with the tumorigenesis or progression. Further support for this conclusion, and indirect evidence that the pseudolipid clones probably do not represent the tumor cell populations, derives from the present study in which clonal and nonclonal structural rearrangements were also found in short-term cultures from nonneoplastic skin and pharyngeal mucosa. It is possible that the aberrations are present in subepithelial fibroblast that have accumulated DNA damage due to extensive exposure to potentially carcinogenic agents.

Adult↗
PubMed1992

Prevention of microvascular thrombosis with low-dose tissue plasminogen activator.

In a blind, randomized study, two groups, each of seven rabbits, were treated with either a very low dose of human melanoma cell line-derived tissue-type plasminogen activator (t-PA) or isotonic saline. t-PA (0.067 mg/kg of body weight) was administered intraaortically, 20 percent being given as a 30-second "bolus" infusion just prior to the reperfusion of intimectomized central ear arteries and the rest as a continuous infusion during the next 2 hours. Arteriotomic bleeding times, accumulations of 32P-labeled platelets, patency, and sizes of thrombus deposits 2 hours after reperfusion were recorded. To confirm the presence of tissue plasminogen activator in plasma, fibrin-plate lysis assays of arterial plasma were performed immediately before and 1/2 hour and 2 hours after starting drug infusion. Arteriotomic bleeding times were similar in both groups. Transient "oozing" from wound edges occurred in 40 percent of rabbits treated with tissue plasminogen activator. Patency was significantly increased and thrombus deposits were smaller in the tissue plasminogen activator group. Plasma from animals treated with tissue plasminogen activator caused massive lysis of fibrin plates, whereas plasma from control animals caused little or no lysis. Platelet accumulations were very similar in both groups, indicating that occlusive thrombi mainly consisted of other elements than platelets (e.g., fibrin and red cells). Scanning electron microscopy showed normally adhering and aggregating platelets in both groups. This study shows that mild fibrinolytic stimulation with tissue plasminogen activator significantly improves patency in severely traumatized small-caliber arteries and indicates that such treatment may be one approach to prevent thrombosis at microvascular anastomotic sites.

Animals↗
PubMed1991

Cytogenetic analysis of 33 basal cell carcinomas.

Cytogenetic analysis of short-term cultures from 33 basal cell carcinomas (BCC), a type of neoplasm for which no previous karyological data exist, revealed clonal chromosome aberrations, all of them different, in 8 tumors. In 2 cases, 2 cytogenetically unrelated clones were detected, suggesting a multicellular origin in at least a subset of BCC. A remarkably high level of nonclonal structural rearrangements, mostly in the form of seemingly balanced translocations, was found in 23 tumors; namely, in 6 of 8 BCC with clonal karyotypic abnormalities and in 17 of 25 without. It is possible that some of these aberrations represent additional neoplastic clones, thus indicating an even higher level of cytogenetic heterogeneity in BCC. We think that the most likely interpretation of the results is that BCC may have a multicellular origin, reflecting field cancerization of the skin. During subsequent tumor development, the selection pressure narrows down the number of clones that infiltrate the surrounding tissue. The finding by karyotypic analysis of some apparently monoclonal, some polyclonal BCC, may reflect that different tumors have been examined at different points in the clonal evolution of the neoplastic cells.

Aged↗
PubMed1991

International survey of current microvascular practices in free tissue transfer and replantation surgery.

The replies to a questionnaire about current microvascular practice circulated to microsurgeons worldwide are summarized and discussed. The material comprises results of 6,594 procedures performed during 1989. The survey topics dealt with include overall success rates in free flap transfer and replantation surgery, antithrombotic therapy, frequency of thrombosis, and frequency of reoperation. At centres not using antithrombotic therapy, the frequency of thrombosis in free flap procedures was higher than at centres using antithrombotic therapy, the result being a higher reoperation rate at the former. However, the final success rates for free flap transfers were about the same (95-96%). The success rate for replantation with antithrombotic therapy was 92%; few centres attempted replantation without such treatment, and at these centres, the success rate was 82%, and reoperation was not attempted. The same modes of antithrombotic therapy and postoperative monitoring are used worldwide.

Europe↗
PubMed1991

Importance of fibrinolysis in limiting thrombus formation following severe microarterial trauma: an experimental study in the rabbit.

In a blind randomized study, two groups of six rabbits were treated with either the fibrinolytic inhibitor tranexamic acid, 14 mg/kg bw, or isotonic saline solution (control group) given intraaortically as single bolus injections 5 min prior to arteriotomy and intimectomy of central ear arteries. Arteriotomic bleeding times, accumulations of 32P-labeled platelets, patency, and sizes of thrombus deposits 2 hr after reperfusion were recorded. Fixed vessels were observed by scanning electron microscopy. Bleeding times were similar in the two groups. The patency rate in the tranexamic acid group was 2/12, i.e., a significant reduction (P less than 0.05) from 7/12 in the control group. Thrombus deposits in occluded vessels contained large amounts of fibrin and red cells. Platelet accumulations in occluded vessels were significantly lower in the tranexamic acid group than in the control group, which indicates that the ratio of fibrin to platelets was increased in thrombi formed during antifibrinolytic treatment. This study has demonstrated the importance of normal fibrinolytic capacity in limiting thrombus formation following microarterial trauma. It is suggested that the use of antifibrinolytic agents in microvascular surgery should be restricted.

Animals↗
PubMed1991

Studies of the antithrombotic effects of dextran 40 following microarterial trauma.

The effects of dextran 40 on platelet function and thrombus formation have been studied in vivo in arteries of the rabbit ear. Intra-aortic infusions of 32P-labelled platelets were followed by infusions of 1.7 g dextran 40 in 17 ml saline/kg b w. Treated and untreated groups were studied using as trauma either end-to-end anastomosis or arteriotomy (7 mm)/intimectomy (5 mm). After restoring blood flow, bleeding times at the sites of anastomosis and arteriotomy/intimectomy were recorded. Accumulations of labelled platelets were followed in vivo for 2 hours, after which patencies were determined and amounts of red thrombotic material evaluated. In a separate series of measurements, haematocrit levels after dextran infusion were studied. Nearly all vessels in the end-to-end anastomosis groups were patent. In the arteriotomy/intimectomy groups, there was a significant increase in patency following dextran infusion. Dextran infusion did not alter platelet accumulation following end-to-end anastomosis, but following arteriotomy/intimectomy median values were somewhat reduced. Its antithrombotic effects must therefore arise mainly at stages of thrombus formation subsequent to platelet deposition.

Anastomosis, Surgical↗
PubMed1991

Adverse effects of topical prostacyclin application in microvascular surgery: an experimental study.

The efficacy of topical prostacyclin as an antithrombotic agent was tested in a model of microvascular trauma. Preliminary measurements were made to determine a suitable dosage. Twenty-seven central arteries of rabbit ears were then prepared and 32P-labelled platelets infused intraaortically. Arteriotomy (7 mm) was followed by intimectomy (5 mm). Fifteen vessels in a control group were irrigated with Ringer's lactate and 12 vessels in an experimental group were treated with prostacyclin (10 ng/ml) in normal saline. Bleeding times at the sites of arteriotomy intimectomy, in vivo accumulations of isotope-labelled platelets, amounts of red thrombotic material, and patency were recorded. Patency was lower following prostacyclin treatment (1/12 as against 5/15) but not significantly so, and there were no statistically significant differences in other parameters. Prostacyclin treatment decreased vessel wall tone, interfering with blood-flow and promoting thrombus formation.

Administration, Topical↗
PubMed1991

Effect of low and ultra low oral doses of acetylsalicylic acid in microvascular surgery. An experimental study in the rabbit.

About 10 h after administering acetylsalicylic acid (ASA) orally in doses of 4 mg and 20 micrograms/kg b.w., the central arteries of rabbit ears were subjected to severe vascular trauma (arteriotomy/intimectomy). Bleeding times from the trauma regions at reperfusion were measured and the activities from accumulating 32P-labelled homologous platelets recorded until 2 h after reperfusion when patencies were determined. In other studies, the effects of ASA on ex vivo platelet aggregation (aggregometry), thromboxane production, euglobulin clot lysis time and bleeding time following arterial puncture were investigated. Relative to controls, the following parameters were changed: patency was increased, as were the bleeding times following arterial puncture and thromboxane production was reduced. The median values of platelet accumulation were lower, but the changes were not statistically significant. Aggregometry showed decreased rates of platelet aggregability following treatment with ASA 4 mg/kg.

Administration, Oral↗
PubMed1991

Pneumatocele after removal of squamous cell carcinoma in the scalp--a rare complication? Case reports.

Two patients with squamous cell carcinoma of scalp had the outer table of the skull opened with an osteotome and a drill. Split skin grafts were applied to the defect in one and delayed split skin grafts in the other. In both cases the lesions were on the vertex and resulted in leakage of cerebrospinal fluid and formation of intracranial pneumatoceles. In one case there was serious disturbance of the central nervous system. We conclude that deep resection within the vertex region overlying the lateral lacuna in close proximity to the sagittal sinus must be done with care and the residual defect should preferably be covered with local flaps.

Aged↗
PubMed1990

Time of low-dose acetylsalicylic acid administration influences in vivo platelet function and thrombus formation following arteriotomy and intimectomy; an experimental study in small arteries of rabbits.

To investigate if low-dose acetylsalicylic acid (ASA), 4 mg/kg b.w., infused peroperatively or 10 hours preoperatively has antithrombotic effects, the central arteries of rabbit ears were prepared and 32P-labeled platelets injected. Arteriotomy and intimectomy were performed and blood flow was restored. Bleeding times at the sites of arteriotomy/intimectomy, in vivo accumulations of isotope-labeled platelets, amounts of red thrombotic material, and patency were recorded. Bleeding times following arterial puncture and the effect of ASA on thromboxane production were studied separately. Ten hours after ASA administration, bleeding times were shortened at the sites of arteriotomy/intimectomy but were prolonged following arterial puncture. Platelet accumulations were lower in patent vessels in this group than in an untreated control group. Peroperative ASA treatment increased but treatment 10 hours prior to blood flow restoration did not significantly affect the number of occlusions. Thromboxane production in ASA-treated rabbits is largely inhibited even 14 hours after administration.

Animals↗
PubMed1990

Hydroxyethyl starch increases patency and reduces thrombus formation following arteriotomy/intimectomy in small arteries: an experimental study in the rabbit.

Twenty-four arteries of rabbit ears, divided into two groups of 12 vessels each, were prepared and 32P-labelled platelets were infused. Arteriotomy/intimectomy was performed after 1 hr and in vivo platelet accumulation recorded for 2 hr. Group A comprised untreated control animals and group B was treated with 1 g hydroxyethyl starch (HES), MW 450,000 in 17 ml saline/kg b.w. (Plasma-steril). Vessel bleeding-times were normal, patency was improved, and intraluminal thrombotic material was reduced after HES treatment. Initial in vivo platelet accumulation was rapid and reached similar levels in both groups. However, the platelet accumulation curves decreased more frequently following HES than in the control group. HES does not prevent platelet accumulation at trauma sites, but reduces the sizes of the thrombi formed and may enhance disaggregation/fibrinolysis.

Animals↗
PubMed1981

Diaphanoscopy and diaphanography for breast cancer detection in clinical practice.

Transillumination of the female breast has during the past few years been reintroduced as an aid in the diagnosis of breast lesions. A series of 259 women with symptoms from the breast were examined by mammography, clinical examination by two independent surgeons, diaphanoscopy by one of the surgeons, diaphanography, and fine needle aspiration biopsy of material taken from palpable tumours. The results were evaluated in order to ascertain the contribution made by transillumination procedures to the diagnosis of malignancy. Carcinoma of the breast was confirmed in 26 women. The malignancy was correctly suggested in 21 and 23 women, respectively, at clinical examination, in 19 by mammography, in 20 by diaphanoscopy, in 16 by diaphanography and in 20 by aspiration cytology. The number of false positive cases was high, especially with the transillumination procedures. All malignancies detected by diaphanoscopy were also believed to be carcinoma at the clinical examination. The three cancers falsely classified as benign at clinical examination were correctly identified as malignant only by mammography or cytology or both.

Adult↗
PubMedDate not supplied

Comparison of surface swab cultures and quantitative tissue biopsy cultures to predict sepsis in burn patients: a prospective study.

This study aimed at evaluating the possibility of predicting septicemia in burn patients by using wound surface and tissue culture techniques as well as blood cultures. Fifty patients with full-thickness burn wounds covering at least 10% of the total body surface area were included. Signs of septicemia were noted in 21 patients (42%) and 29 patients died (58%). The bacterial colonization of the burn wounds consisted mainly of Staphylococcus aureus and Pseudomonas aeruginosa. Sepsis was better correlated to quantitative burn tissue biopsy cultures than surface swab cultures but the time needed for processing limits its predictive and therapeutic value.

Adolescent↗