Ultraviolet 308-nm excimer laser ablation of bone: an acute and chronic study

A comparative study was undertaken in rabbit tibiae to assess the healing of bone in response to osteotomies by a XeCl 308-nm excimer laser and a mechanical saw. The laser parameter producing the most efficient ablation rate for osteotomy was determined and shown to produce deep cuts with sharp edges. However, it was noted histologically that there was a significant delay in healing of the laser osteotomies compared with saw osteotomies. This delay was caused by thermal damage to bone adjacent to the laser cuts. It is suggested that the excimer laser at this wavelength ablates bone primarily through a photothermal as opposed to a photodissociative mechanism.

Pseudolymphoma of the earlobes due to ear piercing

Keloids are commonly seen as a complication of earlobe piercing. As biopsies are usually not performed routinely in many instances, some of the lesions might, in fact, represent other entities, such as cutaneous pseudolymphoma. Contrary to keloids, for which surgery alone is not recommended, a simple excision or superficial x-ray is sufficient in such cases.

Mid-infrared erbium:YAG laser ablation of bone: the effect of laser osteotomy on bone healing

A comparative study was undertaken in rabbit tibiae to assess the healing of bone in response to osteotomies by a mid-infrared erbium: YAG (2.94 microns) laser or a mechanical saw. Laser parameters necessary for osteotomy were shown to produce deep cuts with sharp edges and no gross charring or burning of adjacent bone. However, it was noted histologically that there was a delay in healing of the laser osteotomies as compared to saw osteotomies. This delay was caused by a microscopic zone of damage to bone adjacent to the laser cuts. It is concluded that, although the erbium: YAG laser may be a useful tool in orthopaedic surgery to ablate bone, under the conditions used in this study, there will be a delay in the healing process after laser osteotomy.

Mechanism of tumor destruction following photodynamic therapy with hematoporphyrin derivative, chlorin, and phthalocyanine

The effect of photodynamic therapy on the tumor microvasculature in the first few hours after treatment was studied at the light and electron microscopy levels. BALB/c mice with EMT-6 tumor received ip injections of hematoporphyrin derivative, chlorin, or phthalocyanine, and 24 hours later, the tumors were treated with light at 100 J/cm2 at the appropriate therapeutic wavelength for each photosensitizer. Animals were killed and their tumors removed at time 0, 30 minutes, 1 hour, and 2, 4, 6, 8, 12, 16, and 24 hours after treatment. The results indicate that for all three sensitizers the effects of photodynamic therapy leading to rapid necrosis of tumor tissue are not the result of direct tumor cell kill but are secondary to destruction of the tumor microvasculature. The first observable signs of destruction occur in the subendothelial zone of the tumor capillary wall. This zone, composed of dense collagen fibers and other connective tissue elements, is destroyed in the first few hours after phototherapy. However, the ultrastructural changes seen in this zone are different for the hematoporphyrin derivative, compared with chlorin and phthalocyanine. Binding of photosensitizers to the elements in this zone as well as altered permeability and transport through the endothelial cell layer because of the increased intraluminal pressure may be key features of tumor destruction.

Immunofluorescent localization of cytokeratin intermediate filaments as a means of defining the presence of recurrent basal cell carcinoma

Intermediate filament subunits are reliable markers of cytogenetic origin for both normal and neoplastic cells. Immunohistochemical localization of cytokeratin filaments offers a sensitive and specific means of identifying basal or reserve cells when studying histologic sections of skin biopsy specimens. We have applied this technique on eighteen cases in which unequivocal diagnosis or recurrent basal cell carcinoma could not be rendered by conventional histologic techniques. In three of the cases studied, microscopic islands of basal cell carcinoma could be demonstrated by positive staining with cytokeratin antibodies. In the remaining fifteen cases, the possibility of recurrent basal cell carcinoma could be conclusively eliminated on the basis of negative staining with this antibody. Immunolabeling with tissue specific cytokeratin antibodies by indirect immunofluorescent examination may thus constitute a reliable and relatively simple technique that may serve to establish a definitive diagnosis in equivocal cases of suspected recurrent basal cell carcinoma.

Mapping of the human body skin with the transcutaneous oxygen pressure method

Transcutaneous oxygen pressure (TcPO2) measurements are studied to determine whether location, side of body, sex, and age affect the values at 23 different sites. Measurements were taken on 19 healthy volunteers on one side or the other of the body. Values were similar at all sites with the exception of the forehead, cheek, medial aspect of the leg, and the scapular region. There was no difference between sides of the body or between younger and older subjects. Women had significantly higher values. The results are discussed, and it is concluded that most skin regions can serve as controls for areas under investigation.

Ablation of bone and methacrylate by a prototype mid-infrared erbium:YAG laser

An erbium:YAG laser was used to generate 200-microseconds pulses of mid-infrared 2.94-microns light in both the single and multimode configurations. Laser pulses were focused on the surfaces of both rabbit long bones and methacrylate blocks, and the tissue response was examined histologically. The depth of thermal injury was determined by ocular micrometry. Over all energy levels tested, the erbium:YAG laser produced ablation of bone and methacrylate with minimal thermal damage to adjacent tissue. Increasing the laser energy per pulse produced increasingly wider and deeper grooves in both bone and methacrylate. However, such increase in laser energy produced a proportionately greater increase in the zone of thermal injury in methacrylate as compared with bone. These studies suggest the feasibility of a surgical erbium:YAG laser in orthopaedics and other forms of ablative surgery.

Cystosarcoma phylloides treated by excision and immediate reconstruction with silicon implant

A case of cystosarcoma phylloides in an 11-year-old girl is described. Excision was followed immediately by reconstruction with a silicon implant. To the best of our knowledge, this is the first report of this technique in an adolescent girl. The etiology, incidence, diagnosis, and treatment of cystosarcoma phylloides are described.

Factitious lymphedema of the hand: a diagnostic challenge

A case of factitious lymphedema of the hand is presented. Attention is drawn to this entity and its differential diagnosis. Delayed detection in our case resulted in prolonged and costly hospitalization with some loss of hand function. Treatment should be left to those skilled in psychotherapy.

New technique for intralesional steroid injections

A fast, simple, and accurate method is described for intralesional injections using a laboratory repetitive pipette that was modified for this specific purpose.

Pseudomelanoma following laser therapy for congenital nevus

Benign nevi can be removed by a variety of procedures including surgical excision, electrocautery, slicing off the protruding portion by a shave biopsy, cryotherapy, dermabrasion, etc. Except in the case of complete excision, these procedures may often be followed by recurrence. We describe a congenital nevus that was incompletely removed by CO2 laser therapy. When the lesion recurred, it had clinical as well as histologic features in common with malignant melanoma, although it was completely benign.

Evaluation of the CASPAR alcohol education curriculum

The CASPAR education-prevention program was initiated when experimental results indicated that a 5-hr alcohol education curriculum at a Catholic high school was able to reduce frequent intoxication among teenagers. Attempts to institutionalize such a program in the public schools shows that (1) alcohol education can generate widespread community and school support; (2) workshops can successfully train teachers to adopt a decision-making approach, though close supervision is needed to ensure that this approach is adhered to in classroom teaching; (3) the CASPAR model of alcohol education produces classroom situations conducive to many children feeling free to express alcohol-related concerns; (4) trained teachers can serve as intermediaries between students with alcohol-related concerns and community resources, in particular those resources that are designed to help children from families with alcoholism; (5) the CASPAR curriculum, implemented by trained teachers, produces statistically significant knowledge and attitude gains, whereas alternate programs such as a special-events approach produce smaller knowledge gains and little attitude change; and (6) to a considerable extent, knowledge and attitude gains persist over time, although retention is greater on knowledge items and among older students. The results suggest that there may be a behavioral impact of instruction in the form of reduced alcohol misuse among teenagers, although if there is, it requires intensive and repeated exposure and can be demonstrated in these data only among younger students while they remain in junior high school. Although such results may be viewed as less supportive than the original experiment with which this work began, they do suggest that alcohol education remains an effective prevention strategy.

The effect of ischemia of the dog's colon on transmural migration of bacteria and endotoxin

The purpose of this investigation was to evaluate the effect of temporary ischemia created during the surgical preparation of the colon for resection on transmural migration of bacteria and passage of endotoxin through the ischemic wall of the canine colon. Eighteen dogs were used: in fourteen the colon was devascularized by ligating all marginal vessels. Aerobic and anaerobic cultures and washings for endotoxin assay were obtained from the surface of the bowel at intervals up to 6 hr after creating the ischemia. Peripheral and portal blood samples were also obtained at equal intervals for bacteriologic cultures and endotoxin assay. Bacterial transmural migration was examined in 10 dogs. In 6 of the dogs biologically marked bacteria were introduced into the colon via a rectal catheter before producing the ischemia. In 4 dogs radioactively labeled endotoxin was introduced into the colon in a similar fashion. In all the dogs, surface cultures, both routine and specific for the marked bacteria, were negative for the whole period of up to 6 hr after creation of ischemia. All portal and peripheral vein cultures were also negative. Transmural migration of endotoxin was investigated in 8 dogs, 4 of which served as controls and underwent a sham operation. In the 4 dogs in which the colon was devascularized endotoxin was discovered in peritoneal washings, and in portal and systemic blood samples, as early as 30 min after the preparation of the bowel was completed. In the control dogs endotoxin assays were negative throughout the experiment. In this model up to 6 hr of ischemia did not result in migration of bacteria through the ischemic wall. Endotoxin, however, entered the peritoneum and the blood very soon after producing the ischemia.

Hair-bearing neck flap for upper-lip reconstruction in the male

Reconstruction of the upper lip resulting in a hair-bearing area and a non-hair-bearing lining is described in two cases of full-thickness lip defects. A unipedicled neck flap was used in one case and a bipedicled neck flap in the other, both comprised of hair-bearing and adjacent non-hair-bearing areas. The neck flap has the advantages of providing the two layers of the lip, and the reconstructed lip is not too thick and is mobile and pliable, and the hair resembles lip hair in color, density, and quality. The multiple operative procedures can be performed under local anesthetic.

Effect of thyrocalcitonin on alkaline phosphatase and pyrophosphatase in rat tibia, kidney and intestine

The influence of thyrocalcitonin (TCT) on the enzymes alkaline phosphatase and inorganic pyrophosphatase in rat bone, kidney and intestine was studied.

The rats were injected with TCT every hour for 4 hours. They were divided into groups and were sacrificed 1 h after the first, second, third and fourth injection respectively. The plasma calcium was found to be reduced. Enzyme studies showed that: a) in tibia metaphysis homogenates alkaline phosphatase increased in response to TCT, to 198, 175, 154 and 183 per cent of the non-injected rats after 1, 2, 3, and 4 injections, respectively; inorganic pyrophosphatase was elevated to 356, 209, 221, 425 per cent after the same TCT injections. b) In kidney homogenates alkaline phosphatase was reduced to 75, 53, 79, 68 per cent of the non-injected rats after 1, 2, 3 and four doses, respectively; inorganic pyrophosphatase was reduced to 78, 56, 77 and 71 per cent after the same injections of TCT. c) In the jejunum, alkaline phosphatase was found to be 88.5, 71, 91 and 115 per cent of the untreated rats after 1, 2, 3 and 4 injections, respectively; pyrophosphatase in this tissue was found to be 105, 102, 102 and 113 per cent of the normal under the above conditions.

The results indicate: 1. TCT causes increases in alkaline phosphatase and inorganic pyrophosphatase activities in bone. The increase of pyrophosphatase is significantly more marked than the increase of alkaline phosphatase; 2. in kidney tissue, the action of TCT on these two enzymes is slower and their activities are equally reduced; 3. in the jejunum no significant effect of TCT on the activity of these two enzymes was observed.