bluuebunny/crossref_metadata_2025 huggingface dataset:
Hepatitis C virus infection of mononuclear cells from peripheral blood and liver infiltrates in chronically infected patients
Authors: Zignego Anna Linda , De Carli Marco , Monti Monica , Careccia Grazia , La Villa Giorgio , Giannini Carlo , D'Elios Mario Milco , Prete Gianfranco Del , Gentilini Paolo
Published: March 2007

The mechanisms underlying chronicity of hepatitis C virus (HCV) infection are poorly understood, but the importance of impaired viral clearance by the immune system has been suggested. The prevalence of HCV infection of peripheral blood mononuclear cells (PBMC) was in investigated in 34 persistently infected patients with anti‐HCV (7 with liver cirrhosis, 10 with chronic active hepatitis, 5 with chronic persistent hepatitis, 4 with chronic lobular hepatitis, and 8 healthy carriers) by polymerase chain reaction (PCR). HCV infection of 116 T cell clones derived from liver infiltrating mononuclear cells obtained from 3 patients with chronic liver disease was examined using the same methods. HCV genomic sequences were found in fresh, unstimulated PBMC from 20 patients with cirrhosis, and chronic active and persistent hepatitis, but in none of the healthy carriers and only in mitogen‐activated cells from 1 out of 4 patients with autoresolving chronic lobular hepatitis. Active PBMC infection was confirmed by identification of anti‐genomic HCV sequences in the majority of HCV RNA‐positive cells (fresh or mitogen‐stimulated). A high percentage of T cell clones obtained from liver infiltrates were found to be infected by HCV. These findings suggest that HCV infection of lymphatic cells plays a role in the pathogenesis of chronically evolving liver damage. PBMC may represent a reservoir for latent infection and a site for viral multiplication. © 1995 Wiley‐Liss, Inc.
Seroepidemiology of inoue‐melnick virus in the general population of buffalo, New York
Authors: Ito M.
Published: March 2007

The prevalence of antibodies to Inoue‐Melnick virus (IMV) types 1 and 2 in the general population of Buffalo, New York, was studied. Serum specimens were collected from blood donors, and pediatric sera were provided from the Buffalo Children's Hospital. Neutralizing antibody titers against IMV were measured with established procedures. Very high prevalence of antibodies to both IMV types 1 and 2 were found in sera from children of Buffalo, especially in the age group 15‐19 years (nearly 100%). The antibody positivity gradually decreased with advancing age, except for the groups of age 60 and older. This is in sharp contrast to a previous report examining sera from the people of Osaka, Japan, in which IMV antibody was not found in children under 10 years of age. In the group of teenagers in Buffalo, with high geometric mean antibody titers, an association with any disease was not found. The peculiar distribution of antibodies to IMV was considered to be possibly related to the high incidence of multiple sclerosis (MS) in the Buffalo area, in contrast to the data from Osaka, Japan, which is a low incidence area for MS. © 1995 Wiley‐Liss, Inc.
Human herpesvirus‐6: A survey of presence and distribution of genomic sequences in normal brain and neuroglial tumors
Authors: Luppi Mario , Barozzi Patrizia , Maiorana Antonio , Marasca Roberto , Trovato Raffaella , Fano Rita , Ceccherini‐Nelli Luca , Torelli Giuseppe
Published: March 2007

In an attempt to study the frequency and distribution of human herpesvirus‐6 (HHV‐6) infection both in normal and neoplastic brain tissues in vivo, polymerase chain reaction was used to look for HHV‐6 genomes: 1) in samples, obtained at necropsy, from different regions of the brain of immunocompetent adult subjects and of patients who died of AIDS; 2) in the surgical biopsies of a well‐characterized series of primary brain tumors of neuroglial origin. HHV‐6‐specific sequences were identified in six of nine brain samples from immunocompetent subjects, and in four of seven brain samples from AIDS patients. Viral sequences were identified in the specimens derived either from the grey (frontal cortex and basal ganglia) or from the periventricular white matter. HHV‐6 DNA was found only in 6 of the 37 primary brain tumor biopsies examined. This study provides for the first time molecular evidence of a wide distribution of HHV‐6 infection in the brain tissues of a high proportion of subjects, both in normal and in impaired immunity. In this large series of tumor biopsies the presence of HHV‐6 genomic sequences is a rare phenomenon, arguing against a major role of this herpesvirus in the pathogenesis of primary brain tumors of neuroglial origin in immunocompetent subjects. © 1995 Wiley‐Liss, Inc.
Probable implication of mutations of the X open reading frame in the onset of fulminant hepatitis B
Authors: Kaneko Miki , Uchida Toshikazu , Moriyama Mitsuhiko , Arakawa Yasuyuki , Shikata Toshio , Gotoh Kenichiro , Mima Satoaki
Published: March 2007

A pathogenic role of precore‐defective mutation in the onset of fulminant hepatitis B has been suggested. However, precore‐defective mutants do not always cause fulminant hepatitis B and are not always isolated from affected patients. These findings strongly suggest the presence of some additional important mutations outside the precore region in fulminant hepatitis. In the present investigation an attempt was made to sequence the X open reading frame of hepatitis B virus DNA isolated from seven patients with fulminant hepatitis B and five patients with acute hepatitis B. The latter were used as controls. Since the X open reading frame encodes the X protein and contains the core promoter/enhancer II complex, some critical mutations may enhance or disrupt the replication and expression of hepatitis B virus DNA leading to fulminant hepatitis.

A C‐to‐T substitution was found at nucleotide (nt) 1655, an A‐to‐T substitution at nt 1764 and a G‐to‐A substitution at nt 1766 in 4, 5 and 5 patients, respectively, out of the seven with fulminant hepatitis. These substitutions were not recognized in the patients with acute hepatitis. These mutations might change the function of the X protein and core promoter/enhancer II complex. It is suggested, therefore, that these mutations, as well as the precore‐defective mutation, may play an important role in the pathogenesis of fulminant hepatitis. © Wiley‐Liss, Inc.
Double resistance to ganciclovir and foscarnet of four human cytomegalovirus strains recovered from AIDS patients
Authors: Sarasini Antonella , Baldanti Fausto , Furione Milena , Percivalle Elena , Brerra Roberto , Barbi Maria , Gerna Giuseppe
Published: March 2007

Four human cytomegalovirus (HCMV) isolates from four different AIDS patients treated with both ganciclovir and foscarnet and not responding clinically to antiviral treatment, were studied in order to verify the occurrence of double resistance to both drugs, and to define whether single or multiple HCMV strains could be responsible for the double resistance. Peripheral blood leukocytes (PBL), the relevant conventional viral isolates, and plaque‐purified strains from all four patients were examined by antiviral drug susceptibility testing by an immediate‐early antigen plaque reduction assay and by restriction fragment length polymorphism (RFLP) analysis using polymerase chain reaction (PCR)‐amplified multiple genome regions and endonucleases. All four HCMV strains had a high level of resistance to both ganciclovir and foscarnet. A single HCMV strain was shown to be responsible for the dual resistance in each patient. HCMV strain identity and uniqueness were shown for each of the four patients in blood samples, viral isolates, and plaque‐purified strains. In addition, in two patients the same single HCMV strain shifted progressively from drug sensitivity to ganciclovir and then to ganciclovir‐foscarnet resistance. These findings document that resistance to both ganciclovir and foscarnet of HCMV strains recovered from blood of AIDS patients represents an emerging problem. Although it is known that multiple HCMV strains may cocirculate in the blood of AIDS patients, single strains appear to be responsible for the dual resistance. Molecular mechanisms responsible for the double resistance of the four reported strains are under study. © Wiley‐Liss, Inc.
Immunohistochemical identification of varicella‐zoster virus gene 63‐encoded protein (IE63) and late (gE) protein on smears and cutaneous biopsies: Implications for diagnostic use
Authors: Nikkels Arjen F. , Debrus Serge , Sadzot‐Delvaux Catherine , Piette Jacques , Rentier Bernard , Piérard Gérald E.
Published: March 2007

Early and specific recognition of varicella zoster virus (VZV) infection is of vital concern in immunocompromised patients. The aim of this study was to compare the diagnostic accuracy of histochemical and immunohistochemical identification of the VZV ORF63 encoded protein (IE63) and of the VZV late protein gE on smears and formalin‐fixed paraffin‐embedded skin sections taken from lesions clinically diagnosed as varicella (n = 15) and herpes zoster (n = 51).

Microscopic examinations of Tzanck smears and skin sections yielded a diagnostic accuracy of Herpesviridae infections in 66.7% (10/15) and 92.3% (12/13) of varicella, and 74.4% (29/39) and 87.8% (43/49) of herpes zoster, respectively. Immunohistochemistry applied to varicella provided a type‐specific virus diagnostic accuracy of 86.7% (13/15; IE63) and 100% (15/15; gE) on smears, and of 92.3% for both VZV proteins on skin sections. In herpes zoster, the diagnostic accuracy of immunohistochemistry reached 92.3% (36/39; IE63) and 94.9% (37/39; gE) on smears, and 91.7% (44/48; IE63) and 91.8% (45/49; gE) on skin sections.

These findings indicate that the immunohistochemical detection of IE63 and gE on both smears and skin sections yields a higher specificity and sensitivity than standard microscopic assessments. © Wiley‐Liss, Inc.
Genetic and antigenic characterization of a serotype G6 human rotavirus isolated in melbourne, Australia
Authors: Palombo Enzo A. , Bishop Ruth F.
Published: March 2007

An unusual rotavirus strain, MG6, was isolated from a 16‐month‐old child admitted to hospital with acute gastroenteritis. The virus could not be serotyped (G‐typed) by enzyme immunoassay using standard reagents specific for common serotypes of human Group A rotaviruses. Nucleotide sequencing of cDNA derived from the gene encoding the outer capsid protein, VP7, and deduction of the VP7 amino acid sequence indicated that this strain belonged to serotype G6, a serotype normally associated with viruses causing disease in cattle. This was confirmed by polymerase chain reaction typing and enzyme immunoassay using a G6‐specific monoclonal antibody. The VP4 genotype of MG6 was determined by hybridization of its VP4 cDNA to genomic RNA isolated from standard strains of defined P‐types. This analysis, confirmed by deduced amino acid sequence analysis, classified MG6 into the novel genotype P13. MG6, therefore, is related to the previously described G6P13 human strain PA169, isolated in Italy. The emergence of strain MG6, the first human G6 rotavirus identified in Australia, provides further evidence of reassortment between human and animal rotaviruses. © Wiley‐Liss, Inc.
Seroepidemiology of hepatitis E virus in the Egyptian Nile Delta
Authors: Kamel Moamena A. , Troonen Hugo , Kapprell Hans‐Peter , El‐Ayady Ahmed , Miller F. Dewolfe
Published: March 2007

The seroendemicity of hepatitis E virus (HEV) in an entire village population located in the Egyp‐tain Nile Delta is described. Serum specimens were obtained from 68% of the total population of 1, 850 villagers. The lack of serum specimen was greatest in the youngest age group (< 5). Commercially available enzyme immunoassays (EIA) for antibody to hepatitis A virus (anti‐HAV), to hepatitis B virus core antigen (anti‐HBc), to second‐generation hepatitis C virus (anti‐HCV) core and nonstructural antigen, and to hepatitis E virus (HEV) were used. Only repeated reactive sera were coded as positive. Stool specimens were examined for Schistosoma mansoni by the Kato method and standard methods for the examination of the liver and spleen by ultrasonog‐raphy were used. Unadjusted for nonrespone, the seroprevalence of anti‐HEV was 17.2% (SE ± 1.1). Anti‐HEV seroprevalence increased by age and was not associated statistically with any of the other viral markers including HCV. Anti‐HAV seroprevalence was consistently > 95%, even in the youngest age group (< 5). The overall sero‐endemicity of HEV was higher than reported elsewhere and appears not to have been introduced into the village population recently. © Wiley‐Liss, Inc.
HCV infection in a rural population of the Central African republic (CAR): Evidence for three additional subtypes of genotype 4
Authors: Fretz C. , Jeannel D. , Stuyver L. , Herve V. , Lunel F. , Boudifa A. , Mathiot C. , de Thé G. , Fournel J. J.
Published: March 2007

The prevalence of hepatitis C virus (HCV) antibodies, HCV infection, and genotypes was studied in a rural population of the Central African Republic. In five villages, blood samples were taken from all the inhabitants present during the survey, belonging to Pygmies (299) and to Bantu and Banda ethnic groups (247). Using a second‐generation ELISA screening and confirmation by immunoblot assay for the detection of HCV antibodies, all the Pygmies were negative, whereas seven Bantus/Bandas, aged > 35 years and with no familial relationship, were positive, giving a prevalence of 2.8% in this ethnic group. Five samples were also PCR positive; all belonged to genotype 4, but with three new subtypes identified by phylogenic analysis. These results indicate the co‐existence of different HCV subtypes and raise questions about the natural transmission of HCV in this secluded population. © Wiley‐Liss, Inc.
Social Issues and Body Image Concerns of Port Wine Stain Patients Undergoing Laser Therapy
Authors: Michael Kalick S. , Goldwyn Robert M. , Noe Joel M.
Published: March 2007

When applying lasers to treatment of port wine stains and other flaws of appearance, the physician needs to have an appreciation of the psychological and social aspects of body image as well as the physical aspect. A number of aspects of our society impinge upon port wine stain patients to make their condition psychologically burdensome. Fortunately, the 82 patients in our sample have received extraordinary support from family members in coping with their affliction. As a group they do not display an unusual degree of emotional disturbance in comparision with a normal control population. However, their initial expectations tend to be unrealistically perfectionistic, and many seem to be unwilling to absorb the fact that laser treatment is accompanied by certain hazards and limitations. An especially conscientious adherence to the canons of informed consent with these patients is therefore recommended.
Microvasculature Can Be Selectively Damaged Using Dye Lasers: A Basic Theory and Experimental Evidence in Human Skin
Authors: Rox Anderson R. , Parrish John A.
Published: March 2007

Basic theoretical considerations of the optical and thermal transfer processes that govern the thermal damage induced in tissue by lasers are discussed. An approximate, predictive model and data are proposed for the purpose of selecting a laser that maximizes damage to cutaneous blood vessels and minimizes damage to the surrounding connective tissue and the overlying epidermis. The variables of wavelength, exposure duration, and incident energy density are modeled, and a flashlamp‐pumped dye laser operating at or near the 577 nm absorption band of HbO2, with a pulsewidth (0.3 μsec) less than the estimated, approximately 1 millisecond, thermal relaxation times for microvessels is chosen for experimental exposures of normal Caucasian skin. Highly specific laser‐induced damage to blood vessels is demonstrated both clinically and histologically. This is in striking contrast to the previously reported widespread, diffuse necrosis caused by other lasers. The incident energy and preliminary observations of wavelength and temperature dependence for vascular damage thresholds are consistent with theoretical predictions. Whereas typically 20 joules/cm2 of argon laser irradiation (514 and 488 nm, ∼100 msec) is required to induce widespread thermal damage, the pulsed dye laser requires only about 2 joules/cm2 to induce highly specific vascular damage. The potential usefulness of dye laser‐induced selective vascular damage as a treatment modality for portwine stain hemangiomas and other vascular lesions is discussed. In addition to possible treatment applications, the dye laser or other sources meeting the requirements for producing such damage may also offer a useful experimental tool for inducing predictable damage to microvas‐culature. Histopathologic and clinical studies related to these possibilities are in progress.
Observations on the use of three laser sources in sequence (co2‐argon‐nd: yag) in neurosurgery
Authors: Aldo Fasano Victor
Published: March 2007

In neurosurgical practice the laser can be considered an additional instrument to improve conventional techniques, or even a new method of treatment of some cerebral lesions. A complete laser surgery requires the association of three laser sources in combination. The CO2 laser is useful for cutting small lesions in important brain areas. Nd: YAG is particularly suitable for tumor surgery‐allowing a deeper destruction with predictable effects associated with a more complete hemostasis. The combination Nd: YAG‐Argon has clear indications for irradiation of the vessels.
The power density of a surgical laser beam: Its meaning and measurement
Authors: Fisher John C.
Published: March 2007

This paper discusses the fundamental concepts of matter, energy, power, and power density, with specific emphasis on the power density of a laser. It points out that a laser beam does not have a single, unique value of diameter within which all of its radiation is confined. Therefore, a computation of power density requires both a value of diameter, and the value of the fraction of total power which is transmitted within that diameter. Some possible means of measuring diameter, power, and power density are presented.
Prototype of a Multipurpose Trilaser Unit in a Teaching Hospital Surgical Department
Authors: Chavoin J. P. , Costagliola M. , Laffitte F. , Vachaud M.
Published: March 2007

We describe our experience and the problems we encountered organizing an autonomous surgical unit in which the equipment and organization enable three lasers to be used in many different applications in medicine and surgery. The three lasers—CO2, Nd:YAG, and argon—may now be used by all the departments concerned within our teaching hospital.

As our unit goes into operation, we have determined that we must now begin an evaluation 1) To assess the clinical value of laser usage via the careful selection of cases for laser treatment, the storage of data for future reference on card and computer records, and the assessment of the vital role of the laser within a range of modern therapeutic aids; 2) to achieve technical improvements, by the optimum use of laser sources and related optical equipment; and 3) to assess the economics of the unit, the profitability of bringing together the three types of laser, and the total cost involved.
Mechanisms of Selective Vascular Changes Caused by Dye Lasers
Authors: Rox R. Anderson , Jaenicke Kurt F. , Parrish John A.
Published: March 2007

On the basis of models describing optical and thermal transfer in tissue, it has been shown that unfocused, pulsed 577‐nm laser irradiation of human skin selectively damages microvessels with little or no direct damage to other tissue structures such as the epidermis. This is in sharp contrast to the histologically nonselective necrosis induced by continuous lasers, in which essentially all structures near the site of exposure are damaged. We report here preliminary data in an animal model regarding mechanisms by which tunable dye lasers selectively alter blood and microvasculature. Irradiations of the hamster cheek pouch were used for direct microscopic observations of immediate changes in vessel integrity and morphology, and in the appearance and flow of blood. In 20‐ to 100‐/*m‐ diameter vessels, a sequence of brown discoloration and viscidification of blood, transient hemostasis, permanent hemostasis, and hemorrhage were observed with increasing exposure doses.
Laser Subtotal Meniscectomy in Rabbits
Authors: Whipple Terry L. , Caspari Richard B. , Meyers John F.
Published: March 2007

This study investigates the healing potential of the peripheral rim of rabbit meniscus following laser subtotal meniscectomy. Thirty animals were operated with 23 bilateral meniscectomies and 7 sham controls. When sacrificed at intervals up to 6 months, the harvested peripheral rims demonstrated a devitalized layer of fibrocartilage averaging 17 μm in thickness, indicating an extremely superficial thermal effect of the laser energy utilizing power densities of 20 to 38 W. Viable chondrocytes and minimal alteration of collagen fibril structure and orientation were noted within 20 to 50 μm of the meniscus free margin. By 2 weeks, a proliferation of vascular buds near the free margin of the meniscus was observed with an increase in ground substance production and chondrocyte population. By 10 weeks, the free margin was completely sealed and was composed of logically oriented collagen fibers and only slightly increased numbers of chondrocytes.

It was concluded that the healing potential of rabbit meniscus is unimpaired following laser resection of the central margin, and that the repair process is mediated by a proliferation of chondrocytes, supported in part by neovascularity within the substance of the meniscus.
Photoradiation therapy of endobronchial lung cancers employing the photodynamic action of hematoporphvrin derivative
Authors: Balchum Oscar J. , Doiron Daniel R. , Huth Gerald C.
Published: March 2007

Thirty‐five patients with tumors within the tracheobrochial tree were treated with photoradiation therapy (PRT) employing the photodynamic action of hematoporphyrin derivative (HPD). An effective protocol has been developed consisting of 3.0 mg/kg HPD given intravenously 72 hours prior to the bronchoscopic illumination of the endobronchial tumor sites with red light (630 mm) from an argon pumped dye laser. Light applicators were developed that provided surface (area) and insertion (volume) illumination of tumor masses. Average light dosages of 100 J/cm2 and J/cm were used for surface and insertion illumination, respectively. Delivery rates were 200 mW/cm2 and 400 mW/cm. There was no immediate visible effect such as coagulation or charring noted.

All malignant endobronchial tumors responded. Tumors included primary and metastaic lesions of various histologic types. Response was complete for tumor within the bronchus after one treatment in 80% of instances. The remaining cases required two treatments to obtain a complete response due to the extensive length of bronchus involved or because multiple sites were present. A complete response, that is, the full opening up of the lumen to the bronchial wall, was accomplished in all but one instance. Atelectatic lungs or lobes were re‐expanded and reaerated. Dyspnea and cough became significantly less. The follow‐up achieved to date indicates improvement in symptoms, activity level, and the return to work in a significant number of cases.
Far‐ultraviolet laser ablation of atherosclerotic lesions
Authors: Linsker Ralph , Srinivasan R. , Wynne James J. , Alonso Daniel R.
Published: March 2007

Far‐ultraviolet (far‐UV) (193 nm) laser radiation ablates arterial wall tissue, including noncalcified atherosclerotic lesions, with no apparent thermal damage to remaining tissue. This effect contrasts sharply with the thermal damage produced by visible‐wavelength laser irradiation. The mechanism by which far‐UV radiation interacts with tissue is predominantly photochemical rather than photothermal. Potential clinical applications include thsoe in which geometrically precise removal of tissue, without thermal damage to the reamaining substrate, is desired. Ultraviolet laser catheterization appears practical with respect to the availability of fiberoptic materials and high‐pulse‐rate excimer lasers.
Eye‐safety requirements for Nd:YAG laser application in gastroenterology, urology, and neurosurgery
Authors: Frank F. , Halldorsson Th.
Published: March 2007

The preconditions relating to radiation safety for application of the Nd:YAG laser in the various fields of open and endoscopic surgery are studied. Potential eye hazards of clinical personnel using a Nd:YAG laser photocoagulator in surgical procedures are investigated and methods of eye protection are discussed. The amount of exposure of the eye to radiation back‐scattered from stomach and bladder tissue, as can occur in clinical practice, has been determined for several commercially available rigid cystoscopes and flexible gastroscopes. In addition, the amount of back‐scatter from brain and liver tissue has been established under the usual surgical working conditions.

The International Electrotechnical Commission (IEC) and the American National Standard Institute (ANSI) provisions relating to laser safety are briefly explained in relation to the use of the Nd.YAG laser. The results of experimental investigations are compared with the maximum permissible exposure (MPE) limiting values as per the IEC and ANSI drafts. The precautions necessary for safe application of the Nd:YAG laser in the various medical spheres are described.
The use of the CO2 laser in otolaryngology: Ten years of experience
Authors: Andrews Albert H.
Published: March 2007

Accessory instruments have been developed consisting of retractors, the axial adapter, the slip‐on adapter for the laryngoscope and the lynch suspension apparatus, the upper‐hand abdominal retractor modified, and chain for neurological sponges, and mirrors. The initial bronchoscopic coupler was used until a manufactured one was obtained from Cavitron. In addition to the cases shown in the table, the laser has been used in conjunction with the Department of Ophthalmology, the Department of Orthopedic Surgery, and the Department of Gynecology. The advantages to laser surgery are stated.
Ultrastructural findings after the use of a CO2 laser in carpal tunnel surgery
Authors: Strohecker J. , Piotrowski W. , Lametschwandtner A.
Published: March 2007

The laser beam enables tissue cutting and care of the cut edges, which prevents an increased scar tissue formation. For this reason we have used the laser beam in carpal tunnel surgery for transection or sealing of the transverse carpal ligament since 1981 because scar tissue formation is for the most part the cause of recurrence. Scanning‐electron microscopic studies of the carpal ligament show the difference between the laser and traditional cutting techniques. After using the laser beam, there is no normal tissue structure; the cut surface appears as uneven and rough in contrast to the cut surface of the cold knife.
Continuous wave (CW) and pulsed laser effects on vascular tissues and occlusive disease in vitro
Authors: Davi S. K.
Published: March 2007

Human arterial segments with occlusive defects and acute dog hearts were exposed, in vitro, to high‐energy pulsed and continuous wave (CW) laser beams at argon (514 nm) and Nd‐YAG (1,064 nm) wavelengths, using various pulse powers, durations and pulse repetition rates. The laser effects included vaporization of plaques in the arterial segments and penetration of the pericardial sac, evaporation of pericardial fluid, and discoloration of tissue with crater‐like lesions in the impact zone, all as a result of vaporization of heart muscle tissues. The areas affected and depth of penetration depended on the wavelength, power, pulse duration, and mode of energy deposition. Focused nanosecond Nd‐YAG laser pulses at repetition rates of 40‐50 Hz caused ablation or vaporization of hard plaques and kidney stones in air and saline. Picosecond (mode‐locked) argon laser pulses at repetition rates of 3.8 MHz–average power 6.5 W, peak power of 230 W–caused effective vaporization of hard plaques and kidney stones in air and saline. Picosecond argon laser pulses–average power 1 W, peak power 250 W– were not effective in vaporization. Transmission characteristics of the various types of laser pulses through fiber optic waveguides were determined. The energy and power density required to vaporize fatty and hard plaques and kidney stones were tabulated as a function of laser wavelength, pulse energy, duration, and repetition rates.
The comparative effects of the Argon, Nd:YAG, and Argon‐pumped Dye lasers on human platelets and erythrocytes in vitro
Authors: Doerger Phyllis T. , Glueck Helen I. , Bel‐Kahn J. van der , Taylor Allen , Goldman Leon
Published: March 2007

The effects of three lasers, Argon, Nd:YAG, and Argon‐pumped Dye, on three types of platelet preparations were evaluated. Either EDTA or buffered citrate served as anticoagulants. Platelets separated from plasma and suspended in buffer showed no decrease in counts following lasering, but morphologic damage was evident with transmission electron microscopy (TEM). In platelet‐rich plasma, a fall in counts was noted for the Argon and the YAG (at high energy only) but was absent when the Dye laser was employed. Morphologic damage (TEM), however, was noted with all three lasers. When whole blood preparations were used, more marked changes in both RBCs and platelets were seen in samples collected in EDTA compared with citrated samples. Morphologic damage (TEM) to platelets and RBCs occurred with all three lasers. An artifactual increase in “platelet counts,” the appearance of spherocytes, and an increase in plasma Hb indicated RBC injury. Both platelets and erythrocytes were sensitive to variations in power (wattage) despite constant total energy delivery.
Thermal and optical properties of living tissue: Application to laser‐induced hyperthermia
Authors: Svaasand Lars O. , Boerslid Tone , Oeveraasen Marit
Published: March 2007

This report discusses the thermal distribution in living tissue during hyperthermic treatment with visible or infrared electromagnetic irradiation. The underlying physical mechanisms that determine the transient as well as the steady‐state temperature distribution are discussed. Results from the treatment of a murine tumor model, C3H/Tif mammary adenocarcinoma in C3D2F1/Bom mouse strain, are reported. Total cure, defined by a nonrecurrent tumor, was obtained in 30% of the cases.
Effects of argon, dye, and Nd: YAG lasers on epidermis, dermis, and venous vessels
Authors: Landthaler M. , Brunner R. , Braun‐Falco O. , Haina D. , Waidelich W.
Published: March 2007

The aim of the present study, which was performed at the dorsal aspects of the ears of guinea pigs, was to compare effects of different lasers on epidermis, dermis, and small venous vessels. Irradiations were performed with argon, dye, and Nd:YAG lasers.

In the first series tissue repair processes were studied after argon laser application. Laser defects were excised after 1, 4, 8, and 14 days and were prepared for routine histological examination. The breadth of epidermal defect and extent of dermal coagulation and occlusion of vessels by thrombus formation were examined histologically. In a second series parameters of irradiation (ie, exposure time, laser power) of the three different lasers were changed systematically. Laser‐induced morphological tissue changes could be best observed 24 hours after irradiation. Each of the lasers led to occlusion of vessels by thrombus formation and also coagulated epidermis and dermis. The extent of dermal and epidermal coagulation was less pronounced after dye laser application. Using short exposure times it was possible to reduce the extent of epidermal damage caused by argon and Nd:YAG lasers. Only 50‐msec dye laser pulses led to intravascular thrombus formation without epidermal and dermal damage.
Effects of Nd: YAG laser photoradiation on intra‐abdominal tissues: A histological study of tissue damage versus power density applied
Authors: Brackett Kim A. , Sankar M. Y. , Joffe Stephen N.
Published: March 2007

Liver, spleen, and pancreas were subjected to laser photoradiation of 50– to 100‐Watt power levels. Samples were evaluated by light microscopy at 0 hours and 7, 14, and 21 days. Four zones of cellular damage were visible in liver and pancreas: coagulum, cavitation, acidophilia, and transition. Only the first three zones were clearly visible in the spleen. Mean lateral tissue penetration was 3.1 mm in liver, 3.3 mm in spleen, and 1.0 mm in pancreas. No significant increase in lateral penetration occurred with increasing power. Normal healing was observed in liver and spleen. Pancreatitis was found in all samples at 7 days postoperatively. At power levels of 80 W or less, recovery was observed. Above 80 W, pancreatic pseudocysts and necrosis led to death of the animals.
Biological effects of laser welding on vascular healing
Authors: White Rodney A. , Patrick Abergel R. , Lyons Richard , Klein Stanley R. , Kopchok George , Dwyer Richard M. , Uitto Jouni
Published: March 2007

The feasibility of welding thin‐walled microvessels by laser has been established. This report summarizes our experience using laser welding to repair thick‐walled, high‐pressure, 4 to 8‐mm canine arteries using CO2, Nd:YAG, and argon lasers. The CO2 laser did not produce seals that could withstand arterial pressure. Nd:YAG laser welds were initially successful, but the majority failed within 20 to 40 minutes. The argon laser uniformly sealed 2‐cm‐length arteriotomies that healed rapidly within 4 to 6 weeks and had less foreign body response compared to sutured controls. Laser welding may represent an alternative for repair of small‐and large‐diameter vessels with several advantages compared to conventional suture techniques.
CO2laser in brain stem gliomas
Authors: Mattos Pimenta L. H. , Mattos Pimentar T. M. , Mattos Pimenta A.
Published: March 2007

The author presents his experience with the use of carbon dioxide laser surgery on five patients with brain stem gliomas. Such problematically located tumors, when removed by this freehand, secure, and efficient technique, were completely evaporated with minimum trauma to neighboring tissue. This method represents new hope for these unfortunate patients. Additional time is needed before we can draw the conclusions regarding long‐term results of the treatment described.
Light dosimetry in brain tissue: An in vivo model applicable to photodynamic therapy
Authors: Powers Stephen K. , Tony Brown J.
Published: March 2007

The intensity of blue‐green (488 nm) and red (633 nm) light as a function of increasing distance from an implanted laser fiberoptic source in the brains of anesthetized rats was measured. There was significant (90%) attenuation of the light intensity for both 488 nm and 633 nm at a distance of 2.5 mm from the intracerebral laser light‐emitting source. At greater distances from the light‐emitting source that corresponded to areas in the cerebral cortex, there was greater attenuation of light intensity for increasing distance with 488 nm than with 633 nm because of the increased vascularity of the cortical mantle and absorption of 488 nm by hemoglobin. When hematoporphyrin derivative was given intravascularly, there was increased attenuation of 633 nm through the cerebral cortex that was similar to that seen for 488 nm in normals. Direct assessment of light intensity in living tissue, which we have shown is possible in this report, will aid in our understanding and interpretation of the histological changes that occur following photodynamic therapy.
Photodynamic therapy of endobronchial tumors
Authors: Mccaughan James S. , Williams Thomas E. , Bethel Bradley H.
Published: March 2007

After presensitization with IV hematoporphyrin derivative (HpD), neoplasms in the tracheobronchial tree of 18 patients were treated by photodynamic therapy (PDT) with 630‐nm light from a tunable dye argon laser system delivered through quartz fibers passed through the biopsy channel of a flexible bronchoscope under local anesthesia. Tumor effect was measured by complete response (CR)—no visible tumor in area treated, partial response (PR)—tumor size or degree of obstruction reduced by more than 50% and some response (SR)—tumor or degree of obstruction reduced by more than 20% but less than 50%. One month or less after 30 treatments to 26 areas in 18 patients, there was 40% CR, 57% PR, and 3% SR. All tumors showed at least some response.

Since many of these patients had end‐stage disease, the effect on the clinical condition and symptoms were evaluated using the Karnofsky Performance Status (KPS), oxygen requirements, and the presence or absence of respiratory symptoms. One month after treatment, 61% were clinically improved, with an increase of the average KPS from 48 to 61.

Three patients with stage III primary lung cancer improved from being severely disabled requiring hospitalization to normal activity with effort and lived an average of 3.5 months.

One patient with metastatic colon cancer was palliated from bedrest with continuous oxygen to normal activity with no oxygen for 12 months. A patient with hemoptysis and carcinoma in situ remains biopsy‐ and symptom‐free for 34 months.

A patient with hemoptysis and cough from breast cancer metastases maintained CR, biopsy‐ and symptom‐free for 7 months.

A patient with hemoptysis from recurrence at the bronchial stump maintained CR, biopsy‐ and symptom‐free for 13 months.

Six patients with Stage III primary lung cancer with average KPS of 27 (severe) died in the hospital and lived an average of 5 weeks (two CR, two PR, two SR).

One patient with atelectasis of the right lower lobe re‐expanded 14 days after treatments began.
Endoscopic papillotomy with Nd: YAG laser: An alternative to electrocautery
Authors: Sander Rainer , Poesl Hans
Published: March 2007

With the presentation of two cases of successfully performed endoscopic papillotomies, a new indication for Nd YAG laser treatment in gastroenterology is introduced.

To the extent it thus far has been used, photocoagulation is a complementary alternative method if the usual papillotomy cannot be placed in the right cutting position.
CO2 laser in cancer surgery of the breast: A comparative clinical study
Authors: Ansanelli Vincent W.
Published: March 2007

Review of the literature reveals little to no data regarding the use of the CO2 laser as a surgical modality in the local treatment of breast cancer. This study was undertaken to determine if the CO2 laser is a surgical improvement over the scalpel, influencing patient care during the surgical and postsurgical period. In the author's series, a total of 209 procedures were performed. Within this group, 105 cases were performed with CO2 laser and 104 cases performed with the scalpel. Biopsies were always performed as a separate procedure prior to definitive surgery. This study was not designed to compare cure rates, the medical follow‐up period being 1 year. The results of this study demonstrate a significant improvement in patients' postoperative care, surgical technique, and hospital cost‐effectiveness.
Far‐ultraviolet laser ablation of the cornea: Photoacoustic studies
Authors: Srinivasan R. , Dyer Peter E. , Braren Bodil
Published: March 2007

Wide bandwidth piezoelectric transducers made of thin (9 m̈m) polyvinylidene fluoride film have been used to make time‐resolved measurements of the stress‐wave generated by far‐ultraviolet (193 nm) laser ablation in corneal tissue in vitro. At high fluence (∼ 250 mJ/cm2), ablation commences within 10 ns (± 5 ns) of the laser pulse and generates short acoustic impulses (∼ 30 ns). The time profile of the ablation, when coupled to the energy requirements for ablation from earlier work, allows the estimation of a temperature and a half‐life for the thermal decomposition of the collagen in cornea. These values do not support a photo‐thermal mechanism for the ablation under the experimental conditions.
A histologic study of laser‐induced transmyocardial channels
Authors: James Frederick W. , Kaplan Samuel , Hardy Roger Ian , Goldman Leon , Bove Kevin E.
Published: March 2007

Carbon dioxide lasers are reported to provide ischemic myocardium direct access to blood within the ventricular cavity by inducing transmyocardial channels which maintain patency in long‐term experiments. We have histologically examined the natural history of channels produced with this technique and compared them with transmyocardial channels created by needle puncture. Immediately after application of the laser, four concentric zones vaporization, carbonization, fixation, and transition could be distinguished along the transmyocardial path. Needle puncture channels were fully occluded within 48 hr, whereas laser‐induced channels maintained partial patency for a 2‐week period, after which they also became occluded. It appears likely that the instantaneous vaporization produced by the laser may delay the release of factors which mediate the healing process, but occlusion of channels was universal in this study. It remains to be determined whether or not variables such as wattage, beam diameter, or tissue temperature influence long‐term channel patency.
The use of the carbon dioxide laser permits primary closure of contaminated and purulent lesions and wounds
Authors: Raymond Hinshaw J. , Raul Herrera H. , Lanzafame Raymond J. , Pennino Ralph P.
Published: March 2007

Excision of contaminated and purulent wounds with the carbon dioxide laser makes it safe to close the wounds primarily when certain steps are observed during the operation. The contaminated surface is sterilized with the defocused beam. The surgeons' and assistants' hands should not touch the contaminated areas, and both should wear two pairs of rubber gloves to protect against accidental contamination. All infected tissue is excised completely, and the wound cleansed by copious irrigation and the defocused laser. The wound may then be safely closed by simple sutures, skin graft, or by the rotation of a vascularized musculocutaneous flap. A series of cases are presented in order to illustrate these points.
Preliminary clinical studies with PDT by topical TPPS administration in neoplastic skin lesions
Authors: Sacchini V. , Melloni E. , Marchesini R. , Luini A. , Bandieramonte G. , Spinelli P. , Cascinelli N.
Published: March 2007

Cutaneous photosensitization by topical administration of a porphyrin derivative has been previously reported from experimental studies. Preliminary clinical trials performed at the National Cancer Institute of Milan in the last six months have confirmed the feasibility of treating skin lesions by topical application of photosensitizers. Fourteen cases of basal cell carcinoma were treated by local administration of tetraphenylporphinesulphonate (TPPS), vehicled by azone. Later, the tumor was exposed to a wavelength of 630 nm from a dye laser.

We noted complete remission, as documented by biopsies, in all tumors, with clinical thickness less than 2 mm, whereas partial remission was obtained in tumors with clinical thickness more than 2 mm. Our experience suggests the possibility of a routine treatment by this method for flat basal cell carcinoma and pre‐malignant lesions, with remarkable advantages to conventional therapies. Our results have to be confirmed by increasing the number of cases and length of follow up; our short follow up does not allow us to make definitive claims regarding this therapy.
Bone fracture consolidates faster with low‐power laser
Authors: Trelles M. A. , Mayayo E.
Published: March 2007

Low‐power laser radiation is currently used in the treatment of pain and osteoarticular inflammation. However, the mechanisms of the laser biostimulating effects on tissue are still not completely understood. With laser treatment, we have achieved activation of osseous regeneration in human bone fractures. After 7 years of positive clinical control in human beings, we decided to start an experimental study of fractures in the tibia of mice, histologically controlling its reparation after exposure to 632 nm. He/Ne laser in doses of 2.4 Joules in one point was used. The radiation was directly applied to the area of fracture in a series of 12 treatments (one treatment every second day). By optic microscope we observed, in the treated animals, an important increase in vascularization and faster formation of osseous tissue with a dense trabecular net compared to the control group, which presented only chondroid tissue and poor vascularization corresponding to an earlier stage of bone consolidation (controls were also analyzed by electron microscopy). Potentially, the laser effect might modulate the function of osteocytes, promoting faster metabolism and reaction of bone callus.
Head and neck applications of the milliwatt laser
Authors: Fried Marvin P. , Vernick David M. , Breslin Kathryn Ann , Moll Erik R. S.
Published: March 2007

The head and neck surgeon often uses the carbon dioxide laser. With the advent of new instrumentation, the frequency of usage will increase. The CO2 miliwatt laser offers the adventages of tissue welding, as well as cutting and ablation by virtue of the small spot size produced combined with low power output. Potential applications include microvascular and microneural anastomoses. The milliwatt laser can be used endoscopically for tissue resection with a high degree of precision with power densities comparable to current CO2 lasers. Moreover, the milliwatt laser can be applied to otology for cutting and welding of the tympanic membrane, tissue removal, and stapedotomy.
Quantitative and ultrastructural studies of excimer laser ablation of the cornea at 193 and 248 nanometers
Authors: Puliafito Carmen A. , Wong Kai , Steinert Roger F.
Published: March 2007

Excimer laser radiation at 193 nm and 248 nm was used to create linear etch perforations of enucleated calf corneas. The etch depth per pulse was determined for various exposures, and specimens were examined by light and transmission electron microscopy. Compared to 248 nm, excimer laser ablation at 193 nm was found to have a lower threshold for onset of ablation, less increase in etch depth per pulse at increasing fluences, and less structural alteration in adjacent cornea. For 193 nm, structural alterations were minimal, confined to an area less than 0.3 μm wide, and did not increase with increasing fluence. These studies suggest that clinical strategies for excimer laser refractive surgery will employ the 193‐nm wavelength, with fluence chosen depending on surgical strategy. Ablation exposures above 600 mJ/cm2 at 193 nm may give the most repeatable etch depth.
Simple and sensitive CO2 laser visual screen
Authors: Huang Yao‐Xiong
Published: March 2007

The present paper describes a simple and sensitive CO2 laser visual screen which is made from silica gel with cobalt chloride as indicator. The screen can directly and almost immediately display a clear mode pattern of an exposing CO2 laser beam, it can respond to laser intensities ranging from 80 mW/cm2 to 26 W/cm2. It is suitable for the observation of both high‐power lasers, which are used for surgery, and very low power ones, which are used for biostimulation.
Spectroscopic, morphologic, and cytotoxic studies on major fractions of hematoporphyrin derivative and Photofrin II
Authors: Sun Chung‐Ho , Duzman Eran , Mellott John , Liaw L.‐H. , Berns Michael W.
Published: March 2007

This study characterizes the special properties of hematoporphyrin derivative (HpD) (Photofrin I) and Photofrin II with respect to the absorption and fluorescence spectra of the subfractions of the compounds in both solution and cells. In addition, data are presented demonstrating variation in the spectral amplitudes with respect to the age (shelf‐life) of the commercially available compounds. Data are also presented confirming that fraction III is the active ingredient‐containing fraction with respect to photosensitivity. The morphologic and electron microscopic analyses demonstrate that the first visible effect on cells following porphyrin sensitization can be detected within 1 minute of low level light exposure (10 J/cm2, 630 nm). The initial sites of morphologic damage are the mitochondria.