Biomedical subjects

S Takac

Publications and source records attributed to S Takac.

8 recordsLinked to original sources

PubMed1991

[Reconstruction of the face on the basis of the skull in the case of N. P].

Reconstruction of face based on bone structure of the skull is always performed for identification of an unknown corpse when other procedures prove inadequate. This method requires close cooperation of forensic physicians, stomatologists, anthropologists and artists. First the skull is photographed in Frankfurt position together with a ruler. From this photography of the skull its facial tissues are schematically drawn. After that, the face is reconstructed in clay. The clay is systematically applied to the skull so that eyeballs, nose, lips, ears and other soft structures of the face are formed. It is recommended that hair should be superficially represented or that a wig should be used. It is uncertain whether this complex method can lead to satisfactory results in all cases. However, if the sculpture is conscientiously and correctly executed, the effort will usually be rewarded.

Face↗

PubMedDate not supplied

[Characteristics of laser light].

Laser is one of the greatest technical discoveries of the 20th century. It is important in basic sciences, but particularly in diagnosis and therapy of various pathologic conditions of human organism. It is electromagnetic radiation, not X-irradiation and, as such, it is not expected to produce new generation of iatrogenic malignancies. Laser falls between infrared and ultraviolet on the spectrum mainly in the visible light spectrum. Properties of laser light are: monochromacity (the same color), coherence (all of the light waves are in phase both spatially and temporally), collimation (all rays are parallel to each other and do not diverge significantly even over long distances). Lasers were first conceived by Einstein in 1917 when he wrote his "Zur Quantum Theorie der Strahlung" (the quantum theory of radiation) which enumerated concepts of stimulated and spontaneous emission and absorption. Drs. Arthur Schawlow and Charles Townes, in 1956, extended lasers into the optical frequency range and Maiman, in 1960, operated the first laser using ruby as the active medium (ruby laser). Laser is an acronym for Light Amplification by Stimulated Emission of Radiation. To understand the acronym, it is necessary to understand the basic physics of the atom. However, if the atom that is in the excited state is struck by another photon of energy before it returns to the ground state, two photons of equal frequency and energy, travelling in the same direction and in perfect spatial and temporal harmony, are produced. This phenomenon is termed stimulated emission of radiation. An external power source hyperexcites the atoms in the laser medium so that the number of atoms possessing upper energy levels exceeds the number of atoms in a power energy level, a condition termed a population inversion. This "pumping system" which imparts additional energy to the atoms may be optical, mechanical, or chemical. These atoms in a hyperexcited state spontaneously emit photons of light. The laser chamber or optical cavity contains an active lasing medium which usually determines the name of each laser. There are four types of lasing material commonly employed. Solid state lasers use a solid matrix material such as a ruby crystal. Gas lasers use a gas or mixture of gases such as helium, argon, and CO2. Dye lasers employ a complex organic dye in liquid solution or suspension such as rhodamine. Semiconductor lasers use two layers of semiconductor substances such as gallium arsenide.

Humans↗

PubMedDate not supplied

[The CO2 laser and verruca vulgaris].

INTRODUCTION: Verruca vulgaris, or a common wart, is a benign epithelial contagious tumour. It is usually flesh-coloured hyperkeratotic papule of a small size (few millimetres in diameter) although sometimes it may reach up to 2 cm in diameter. Milder, more conservative chemical therapy often requires weeks or months and is often unsuccessful. More aggressive therapy (e.g. electrodesiccation and curettage) may result in significant morbidity, tissue damage, and scarring. Plantar warts are particularly problematic. CO2 laser has numerous applications in dermatology and dermatologic surgery. It is versatile, being either a vaporising tool or a light scalpel. CO2 laser is an excellent modality for treating problematic or recurrent warts. In our experience it has now become the method of choice for warts. The aim of the present investigation was to evaluate the efficacy of the laser treatment in comparison to more conventional forms of treatment. MATERIAL AND METHODS: Surgical laser was used at 15 W power at superpulsating, pulsating and continuous beam. The wavelength was 10,600 nm and the laser was used at infrared spectrum. Active substance was CO2 in combination with nitrogen and helium at following proportion: CO2:N2:He = 4.5%:13.5%:82%. It was used under the pressure of 20-80 mbars. Lesions are treated with laser in a focused mode at low to medium-power density in a series of brief pulses (0.05-0.1 sec). Treatment was carried out under magnified vision (2.5x magnifying loupes) in order to see all small satellite warts and to judge more precisely when all wart tissue has been vaporized. All interventions were performed under local anaesthesia with either carticaine-chloride or 2% lidocaine-chloride. All interventions were performed between 1992-1996 in an outpatient clinic. Warts were excised with a combination of vaporization and resection of the wart root. RESULTS: The laser beam promptly sterilized the operative field more efficiently than any other commonly used disinfectant. Healing was by granulation and the post-operative period was relatively painless for the patient. Healing resulted in either no scar or a supple flexible scar which was asymptomatic. DISCUSSION: Verruca vulgaris most often occurs on fingers and hands of children and teenagers (most commonly between ages 18 to 20). Resistance to therapy is common, and recurrences are frequent. Carbon dioxide laser is a high-precision, bloodless light scalpel used for incising and excising tissues with sealing of small blood vessels. It is the treatment of choice for local destruction of intraephithelial neoplastic lesions. The carbon dioxide beam may be used to remove tissue in one of two ways. First, the lesion may be vaporized until a bed of healthy tissue is reached. The second and better technique is to use the beam as a scalpel to excise a lesion with appropriate margins. Post-operative morbidity and complications are low, and long-term results appear to be excellent. CONCLUSION: Laser therapy of common warts is a novel form of treatment of these papillomavirus-induced skin tumours. Our results show that this method has numerous advantages over more conventional forms of treatment.

Adolescent↗

PubMedDate not supplied

[Lasers in dermatologic surgery].

The authors review their experiences with the use of carbon-dioxide (CO2) lasers in dermatological surgery in a group of 3000 patients, with a total number of 3920 tumorous skin lesions, during a three-year period. The word LASER is an acronym for L-ight A-mplification by S-timulated E-mission of R-adiation. It must be pointed out that it is electromagnetic radiation, not X-irradiation. In regard to the spectrum laser light is between infrared and ultraviolet light, mainly in the visible spectrum, so its application does not produce new generations of iatrogenic malignancies as in the case of ionizing radiation. The laser is a new scalpel which differs from the metal surgical scalpel (also called "optical knife" and "light scalpel"). In the conclusion authors state that using (CO2) complete success was achieved in treatment of the following skin lesions: common viral warts, senile keratosis, seborrhoeic keratosis, plantar viral warts, papillomas, capillary telangiectasias of the face, hemangiomas, juvenile viral warts of the face, ingrown nails, condyloma acuminata, pendular fibromas, xanthelasmas, atheromas, pyogenic granulomas, keratoacanthomas, tattooed skin and basocellular epitheliomas.

Adolescent↗

PubMedDate not supplied

[A suicide by hanging suspected to be a homicide].

The paper presents a case of suicidal hanging that was suspected to be a homicide. The reasons for that were of circumstantial origin. The hanging took place in the woods, the victim had his hands tied and was with a hankerchief in his mouth. Those elements were the arguments in favor of the mentioned suspicion.

Forensic Medicine↗

PubMedDate not supplied

[Types of medical lasers].

The knowledge about different types of lasers and their potential use in medicine is presented. A very rapid development of laser technology in the world imposes a need for up-to-date information about the characteristics of different laser instruments. Without this kind of information it would be difficult to keep in touch with the latest developments in the world's technology. Different types of lasers have different indication range in the medical practice. An inquiry into the fundamental principles of lasers physics is an important prerequisite for successful application of this technology in medicine. Laser as a surgical knife has shown certain advantages over scalpel, electrocautery and cryosurgery, as the laser surgery is a noncontact method, bloodless, precise, with better visualization, minimal postoperative edema, painless healing, without complications. Although laser cannot entirely replace conventional surgical instruments, it is still the instrument of choice for treatment of numerous pathological conditions. The carbon dioxide laser is a highly precise, bloodless light scalpel used for incising and excising tissues and sealing small blood vessels. The infrared beam at 10,600 nm wavelength is absorbed by water and tissue destruction is due to the instantaneous vaporization at relatively low temperature of 100 degrees C. The beam seals blood vessels of up to 0.5 mm in diameter and if the beam is defocused, larger vessels may be controlled. The beam also seals lymphatics, possibly reducing the spread of tumour cells by this route, and seals nerve endings: there is no incidence of neuroma formation. Carbon dioxide laser has shown a great efficiency in otorhinolaryngology, in maxillo-facial surgery and plastic surgery, in urology and gynecology. Provides true "no touch" surgery, and is used increasingly in neurosurgery for the precise atraumatic removal of tissue and for creation of precise lesions for the control of pain. The carbon dioxide laser beam cannot, at present, be transmitted via a flexible fibre, although a number of fibres are being investigated. Delivery of laser energy to microscope, colposcope or handpiece is via an articulated arm which is a hollow tube with mirrors at the articulations. The argon laser produces blue-green coherent light at a number of wavelengts but 80% of the energy is at wavelengths of 488 and 514 nm. This laser was first used in ophtalmology to treat diabetic retinopathy through, and without damage to, the clear anterior parts of the eye. The argon laser is used for blood vessel coagulation but can be used to perform slow, thermal tissue destruction at higher power levels. Argon laser is most commonly used in ophthalmology for otological micro-surgery, particularly in the treatment of otosclerosis and tympanosclerosis. Very good results have been achieved in the argon laser treatment of gastrointestinal bleeding ulcers, vascular lesions and polyps. Dermatology is another field where argon laser has shown great efficiency: hemangyomas, telangiectasias, tattoos, small benign and malignant tumours are amenable to argon laser treatment. In neurosurgery it is used to control both normal and abnormal blood vessels but at present much work on treatment of arteriovenous malformations and aneurysms is experimental. Both the argon laser energy can be transmitted via flexible fibre optic delivery system which can then be attached to an operating microscope, slit lamp, endoscope delivery fibre or handpiece. The Neodymium-YAG laser is used both for tissue destruction with good haemostasis and for the control of normal and abnormal blood vessels. This laser produces infrared coherent light at 1060 nm wavelength, which is deeply absorbed in the tissues without colour or tissue specificity. Neodymium-YAG laser is mostly used in tracheobronchial, gastrointestinal and urologic pathology in the treatment of stenoses, granulomas, benign tumours, and for reduction of malignant tumours. (ABSTRACT TRUN

Laser Therapy↗

PubMedDate not supplied

[Diagnostic and biostimulating lasers].

In this brief report authors present data regarding the application of diagnostic and biostimulating laser instruments in medicine. For diagnostic purposes there are several types of laser instruments and procedures available: Laser Microscopic Masonic Analyzer (LAMMA), Flow cytometry. Doppler effects of laser rays (Laser Doppler velocytometry, Laser Doppler spermokhinezymetry, Laser Doppler spectrometry), Laser fluorescent microscopy, Laser nephelometry, Transilumination by lasers (diaphanography), Laser spectroscopy, Laser holography, Laser rethinoscopy, Microirradiation by lasers. Literary data concerning favorable effects of low power laser radiation on series of diseases covering different medical specialties are cited, pointing to possibility of significant enrichment of already available arsenal of physical methods, thera-pies and rehabilitation procedures. Mechanisms of biostimulation of human tissues and organs under low power laser radiation are also presented. All these stimulatory and regulatory mechanisms of the cell metabolism are involved in the wound epitelization, reduction of edema and inflammation and reestablishement of arterial, venous and lymph microcirculation and consequently inducing better tissue nutrition. The use of laser spectroscopy for quantitative analysis of cations from a single drop of dried blood on a piece of filter paper was not realized, although individual analyses of frozen skin biopsies for calcium, arsenic and gold were accomplished. In Europe, this technique has also found its application in forensic medicine. Furthermore, laser-based methods have been used to study air pollution with carcinogens in occupational exposures and also for the detection of narcotic drugs. Laser cytofluorometry utilizes the argon laser for scanning of single stained cells and has achieved utilization in mass examination programs for Pap-smear determinations. The same technique is used in cell sorting system that is now important in monoclonal antibody determination in hybridoma technology. Other possible diagnostic applications include laser particle size measurement techniques, and laser nephelometry for determination of immunoglobulins classes and autoantibodies such as rheumatoid factors. Laser Doppler velocimetry is used to measure blood flow by means of a simple probe that rests on the lip. Biostumulating laser instruments The world famous Hungarian scientist Mester Endre, from Budapest, is one of the pioneers with the greatest experimental and clinical experience in the use of biostimulating effects of lasers. His former student, O. Ribari first used biostimulating effects of He-Na laser (390 mJ power) for the epitelization of perforated tympanic membrane and treatment of postoperative fistulas of the neck and of the mastoid. Generally speaking, biostimulating effect of low level laser treatment (LLLT) is in its anti-inflammatory, analgesic and anti-edematous effect on tissues. There is absolute increase in microcirculation, higher rates of ATP, RNA and DNA synthesis, and thus better tissue oxygenation and nutrition. There is also increase in the absorption of interstitial fluid, better tissue regeneration and stimulation of the analgesic effect. The past three decades of laser medicine and surgery have shown great progress and promise for the future.

Humans↗

PubMedDate not supplied

[Classification of laser irradiation and safety measures].

The use of lasers in medicine and especially surgery is rapidly expanding in many disciplines from clinical laboratory to the office practice and operating room. It is essential that users of this powerful tool have knowledge of their potential hazards and the measures to protect patients and personnel against injuries or undesired effects. Below, we have included information about the way lasers are classified; the development of protective standards; the current status of protection standards that apply to lasers, especially those used in medicine/surgery; the specific kinds of hazards associated with medical/surgical applications; and the measures by which hazards have been controlled. Since laser technology is still a young field, it is likely that problems unknown at present will occur and methodologies for controlling hazards will evolve. The American National Standards Committee produced the first consensus standard Z136.1 in 1973. The Standard was revised in 1976 to accommodate differences in biological effects for different wavelengths in the visible spectrum. The ANSI Standard has been revised again in 1980, and currently (1984) there are two additional standards in preparation, Z136.2 and 136.3, which treat the safe use of light-emitting diodes and the safe use of lasers in the health care environment, respectively. Most surgical and medical lasers are Class III or IV. Some lasers have a Class IV therapy level beam plus a Class I or II alignment beam. When using lasers, it is possible to generate incandescence or fluorescence in an irradiated object. This can occur even with protective eyewear, because the correlated radiations are usually of a different wavelength. Generally, this should not be a problem when beams are directed at biological material. However, hazard could be caused by lasers designed to produce fluorescence. Control of correlative radiation in a laser system is required in the federal regulations. Hazards of lasers may be grouped as those to the eye, skin and associated hazards, fire, x-rays, electrical, fumes, toxic materials, etc. Effects on tissue are governed by the following factors:--the energy or power density of the beam;--the absorption in tissue at the laser wavelength;--the time the beam is held at a given area.;--the protective effects of heat removal by thermal conduction and by circulation. Eye hazards include thermal burns or acoustical disruption (shock waves) from high-powered or high-energy beams in the visible and near infrared wavelengths. Direct beam exposure or specular or diffuse reflaction from these very high-power lasers can also cause injuries to other parts of the retina. For example, beams can directly penetrate through the sclera and cause retinal injury. Near ultraviolet (less than 400 hm) and far infrared (.3000 hm including CO2 lasers) can cause moderate to severe corneal burns. Far ultraviolet (200-315 nm), mid infrared (1400-3000 nanometers) can cause welders' flash or snow blindness and chronic exposure could cause cataract, and exposure to ultraviolet rays may be carcinogenic. For CO2 lasers, the far infrared radiation is attenuated by plastic goggles, or by glasses, or quartz. Other eyewear with special filters is used for different lasers. The whole personnel who may be exposed to direct beams, specular reflections, and many times diffuse reflections must wear protective eyewear. In all cases the surgeon and others viewing the procedure through the endoscope need glasses or suitable protective lenses installed in the endoscope. Persons who are not viewing the beam may not need to wear protective glasses with the same level of optical density. Glasses may be selected to provide protection for lasers operating in the visible wavelength to the point where the normal aversion response could protect the individual.

Eye Injuries↗