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Biomedical subjects

D W Rogers

Publications and source records attributed to D W Rogers.

At least 55 records · Page 3Linked to original sources
PubMed1990

Blood contamination of anaesthetic and related staff.

The incidence of skin contamination of anaesthetic and related staff by patient's blood and saliva was studied during 270 anaesthetics in Cardiff hospitals over seven continuous days in October 1989. A survey was also made of current Hepatitis B immunisation status and glove-wearing habits of 75 anaesthetists. Blood from 35 (14%) patients caused skin contamination of 65 staff during 46 incidents. Twenty-eight (61%) of the contamination incidents occurred during vessel cannulation. Five (8%) of the 65 staff contaminated by blood already had cuts on their hands. There were nine incidents (4%) of skin contamination by saliva. Fifty-three (71%) anaesthetists were immunised against Hepatitis B. Only seven (9%) anaesthetists wear gloves for oral or nasal intubation, six (8%) for insertion of peripheral venous cannulae, 47 (63%) for insertion of arterial lines and 67 (89%) for insertion of central lines. All anaesthetic and associated staff should wear gloves on a routine basis.

Anesthesiology↗
PubMed1989

Beneficial effects following carbon dioxide laser excision on experimental neuroblastoma.

Treatment of neuroblastoma in children consists of primary excision with adjuvant radiation and chemotherapy. When the tumor invades surrounding structures that cannot be safely excised or when distant metastasis is present, the patient has a poor prognosis. Because the CO2 laser can be used to excise malignant tumors without seeding the surrounding tissue and because the defocused beam can vaporize malignant cells, we compared partial scalpel excision and partial laser excision of C1300 murine neuroblastoma to the growth rate of residual tumor. In 25 mice, 75% of the tumor was excised with a scalpel, and in another 25, the same percentage was excised with the CO2 laser (10 W). CO2 laser excision significantly decreases the growth of residual neuroblastoma (P less than .01). However, the effect appears to be a function of increased tumor immunogenicity after laser excision rather than the increased tumor kill. We conclude that CO2 laser excision of neuroblastoma may prove to be superior to scalpel excision for primary surgical treatment of neuroblastoma.

Animals↗
PubMed1989

Monoclonal antibodies for detecting bone marrow invasion by neuroblastoma.

One hundred and sixty six bone marrow aspirates from children with abdominal neuroblastoma were independently examined for the presence of neuroblastoma cells by conventional haematological staining techniques and by indirect immunofluorescence using one or more of five monoclonal antibodies. Results using the two methods were evaluated by comparison with the results of bone marrow, bone and lymph node biopsy specimens taken at the same time, and in the light of the child's clinical course. One antibody, UJ13A, was found to have 98.5% specificity and 85.7% sensitivity, compared with sensitivities for conventional staining of 50% for aspirate alone and of aspirate or trephine biopsy specimen of 71.4%. The remaining antibodies UJ127/11, UJ223/8, UJ181/4 and UJ167/11, with specificities in the range 94-99%, were found to have sensitivities in the range 47-61%, lower than the sensitivity of conventionally stained aspirate or trephine biopsy specimen. Routine immunofluorescence staining with monoclonal antibody UJ13A should increase the sensitivity of detection of metastatic neuroblastoma.

Abdominal Neoplasms↗
PubMed1988

Comparison of continuous-wave, chop-wave, and super pulse laser wounds.

Some of the latest generation of CO2 lasers incorporate features that alter the wave form. The present study was undertaken to evaluate the relative zone of coagulation in acute laser wounds created in continuous-wave (CW), chop-wave (CPW), and super pulse wave (SPW) modes. The damage from single-point impact sites and incisions was compared in a guinea pig model. Animals were anesthetized with pentobarbital, and wounds were created with a 125-mm handpiece in focus (0.2-mm spot size) on dorsal and flank skin sites with the Sharplan 743 and 1100 CO2 lasers (Sharplan, Ltd., Allendale, NJ). Point impacts of CW and CPW were compared at power levels of 5, 10, 25, 40, 60, and 80 W at time durations of 0.05, 0.1, 0.2, and 0.5 seconds. Incisions of 3.0 cm were created at 25 W in CW, CPW, and SPW modes. Histologic sections stained with hematoxylin and eosin and Van Giesen elastin stains were evaluated by a single observer (R.J.L.). Zones of coagulation for the point-impact study varied from 79 to 257 +/- 66 (SD) micron in width with no significant differences between any of the wounds. Greater thermal damage (coagulation) occurred as the time interval increased. The zones of coagulation in the incision study were 309 +/- 83 (SD) micron for CW, 238 +/- 51 (SD) micron for SPW1 (743), 260 +/- 79 (SD) micron for CPW, and 194 +/- 56 (SD) micron for SPW2 (1100). These results are significant to the P less than 0.01 level.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Comparison of local tumor recurrence following excision with the CO2 laser, Nd:YAG laser, and Argon Beam Coagulator.

This study compares the incidence of local tumor recurrence following primary excision with the CO2 laser, Nd:YAG laser (contact), Argon Beam Coagulator, or electrocautery. One hundred eight Fisher 344 rats with R3230AC mammary tumors (1.6 +/- 0.04 [SD] cm diameter) were used. All animals were randomized into groups of similar tumor size. In groups C and CS, excision was performed with a Sharplan 1060 CO2 laser (TEMoo, 25 W, continuous wave [CW], 0.2-mm spot size). Wounds in group CS were "sterilized" (0.5-mm spot size, 25 W, CW) by gently heating the wound without causing blanching or charring. In group N, a 0.4-mm contact Laser Blade and a Cooper 8000 Nd:YAG laser at 20 W CW was used. In groups SA1 and SA2, tumors were excised with the scalpel, and hemostasis and wound "sterilization" were accomplished with the Bard System 6000 Argon Beam Coagulator (ABC) at 40 W and 4 liters/min argon gas flow in SA1 and 12 liters/min in SA2. In group E, excision was accomplished at 40 W blend mode, 10 W spray mode. In group EA, excision was accomplished at 60 W cutting current, and hemostasis was achieved with the ABC. The animals were examined for evidence of recurrence for 34 days postoperatively. Mortalities were excluded from analysis. The incidence of recurrence was 11/14 (79%) in C, 6/16 (38%) in CS, 10/14 (71%) in SA1, 6/13 (46%) in SA2, 6/15 (40%) in N, 7/10 (70%) in EA, and 3/15 (20%) in E. Group E is statistically different (P less than .01) from groups EA, C, and SA1. Group C was different (P less than .01) from groups E, CS, and N. These results demonstrate an inverse relationship between tumor recurrence and local thermal effects at the surgical site. The ABC did not increase tumor recurrence. Contact YAG surgery was similar to CO2 laser excision and "sterilization." An attempt to study the influence of gas flow and pressure on local tumor recurrence and metastases should be made.

Adenocarcinoma↗
PubMed1988

Generation of photon energy deposition kernels using the EGS Monte Carlo code.

The EGS Monte Carlo code was used to generate photon energy deposition kernels which describe the energy deposited by charged particles set in motion by primary, first scattered, second scattered, multiple scattered and bremsstrahlung plus annihilation photons. These were calculated for a water medium irradiated with monoenergetic photons with energies in the range 0.1-50 MeV. In addition to the primary energy deposition kernels, primary charged particle transport was further characterised by computing the effective centre of the voxels, and the effective penetration depth, effective radius and effective lateral distance travelled by these particles. The dose per unit collision kerma for parallel monoenergetic primary photons beta' was calculated. Additional applications of the energy deposition kernels are discussed.

Computer Simulation↗
PubMed1988

Mechanisms of reduction of tumor recurrence with carbon dioxide laser in experimental mammary tumors.

This study compares local tumor recurrence after low energy CO2 laser wound sterilization with recurrence after scalpel, laser or electrocautery excision. Wound histologic changes were studied to understand the mechanism of the interaction between the laser and wound. Single implants of R3230AC mammary tumor were grown to an average diameter of 24 millimeters in the mammary ridge of 80 female fisher 344 rats. Rats were anesthesized with pentobarbital and randomized into groups, each with similar tumor size: scalpel (S), laser (L), laser with wound sterilization (LV), scalpel with sterilization (SV) and electrocautery (E). All surgical procedures were performed by the same surgeon with the same technique, with the exception of the instruments used. Tow rats from each group were sacrificed immediately and the wounds examined histologically. The Sharplan 1100 CO2 laser was used with a 125 millimeter hand piece in focus and in continuous wave for groups L and LV. Sterilization in groups LV and SV was performed with 5 millimeter spot size by heating the site gently without causing blanching of tissue. Excision in group E was performed with coagulating current from a monopolar cautery (Valley Lab). Rats were examined periodically for 30 days and those dying during this period were excluded from analysis. The incidence of wound recurrence was eight of 12 in group S; five of eight, L; four of 13, E; three of 12, LV, and two of nine, SV (p less than 0 .05). Histologic changes in the wound demonstrated viable tumor in all groups, with fewer areas present in groups E, SV and LV. Local thermal effects and the noncontact nature of the CO2 laser make it an effective adjunct in reducing local tumor recurrence by enhancing the cytoreductive capability of surgical procedures.

Adenocarcinoma↗
PubMed1987

The influence of hands-on laser training on usage of the CO2 laser.

A questionnaire was distributed to all participants in the Rochester General Hospital CO2 laser training workshops for surgeons (1982 to January 1985). The results of this study indicate that, while laser training is necessary prior to being able to use the laser, only a small fraction of trainees actually use the laser in their clinical practice. Surgeons who are using the laser do so in a minority of their cases. New incentives for laser usage must be investigated.

Education, Medical, Continuing↗
PubMed1987

Effect of hematoporphyrin derivative 2 on estrogen receptors in experimental mammary tumors.

This study reports the effect of hematoporphyrin derivative 2 (HPD2) on estrogen receptors (ER) in the animal model used to develop the clinical ER assay. Fifty 200-g female Sprague-Dawley rats were given 20 mg of dimethylbenzanthracene by gastric intubation. Spontaneous mammary tumors occurred in 35 animals. Animals were anesthetized and 50% of each tumor was removed when the tumors were 2 cm in diameter. Animals were then randomized to receive 5 mg/kg (group A), 10 mg/kg (group B), or 0 mg/kg (group C) HPD2 intravenously 48 hours after biopsy. The remaining tumor was excised 48 hours post HPD2 injection. All samples were weighed, placed on ice, and frozen to -70 degrees C. ER assay was performed by batch run. Results (fmol/mg cytosol) were as follows: All animals (n = 35) pre HPD2 34.2 +/- 5.4, post HPD2 34.2 +/- 5.8; group A: (n = 11) pre HPD2 33.9 +/- 7.9, post HPD2 37.1 +/- 7.8; group B: (n = 13) pre HPD2 29.2 +/- 3.8, post HPD2 25.5 +/- 3.6; group C: (n = 11) pre HPD2 40.3 +/- 5.2, post HPD2 41.5 +/- 7.9. HPD2 does not affect ER in this animal model. Confirmatory studies with human tumor material must be completed.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1986

Bone-marrow transplantation has a limited role in prolonging second marrow remission in childhood lymphoblastic leukaemia.

Fifty-three children with acute lymphoblastic leukaemia whose first complete remission ended in bone-marrow relapse received similar reinduction and consolidation therapy. Thirteen had an HLA-compatible sibling donor and were eligible to receive a bone-marrow transplant (BMT); five survive, all off treatment in continuing remission. Forty had no donor and received further chemotherapy; sixteen survive, twelve in remission and six off treatment. After 1-5.5 years' follow-up from relapse, there is no significant difference in survival between the groups. The major obstacle to success is marrow relapse which occurred in two eligible patients before BMT could be carried out. The lengths of first and second remissions in both groups were significantly correlated. Morbidity in survivors was substantial. The scope of BMT as retrieval therapy for ALL is limited by the instability of second remissions; this difficulty will not be overcome by increasing the number of potential donors or the use of autologous marrow.

Adolescent↗
PubMed1986

The effect of CO2 laser excision on local tumor recurrence.

This study was undertaken to determine the effect of CO2 laser surgery on the incidence of local recurrence following tumor recurrence and to study the effect of "sterilization" of the operative site on this phenomenon. Sixty Fisher 344 rats were implanted with R323OAC mammary carcinoma. Animals were anesthetized with intraperitoneal pentobarbital, and all tumors were completely excised at 21 days postimplantation. The animals were randomized into groups of 12 as follows: Group S underwent excision with the scalpel. Group E underwent excision with electrocautery (Bovie, Valley Labs, Boulder, CO). Group L and LV underwent excision with the Sharplan 733 CO2 laser (Laser Industries, Israel) (TEMoo, 125-mm handpiece, 25-W continuous wave). Group LV wounds were then "sterilized" by using the laser defocused to a 5-mm spot size and gently heating the site without producing blanching or charring of the tissues. Primary tumor size was 2.0 +/- 0.5 cm and was similar in all groups. Animals were observed for recurrence for 33 days postoperatively. Mortalities were excluded from analysis. Tumors recurred in 7/9 (78%) in group S, 5/11 (45%) in group E, 4/10 (40%) in group L, and only 1/12 (8%) in group LV. All results are significant at P less than 0.05. The CO2 laser is an effective surgical adjunct to reduce local tumor seeding and recurrence. This effect is enhanced by "sterilizing" the surgical site with the defocused laser beam.

Animals↗
PubMed1986

Bursting pressures of CO2 laser-welded rabbit ileum.

In this study, the short-term bond strength of laser-welded New Zealand white rabbit ileum was examined. Forty-eight longitudinally oriented 0.5-cm transmural, scalpel incisions were reanastomosed solely through the use of the CO2 continuous wave laser at low energy levels. Random power levels of 250, 500, 750, or 1,000 mW were delivered to weld sites by either continuous application for 30 seconds or a pulsating application (ie, 0.5 seconds on, 0.5 seconds off) for 60 seconds. This provided 53.6, 107.1, 160.7, and 214.3 J/cm2, respectively. With the aid of a plexiglass clamp and pressure monitored infusion system, each type of weld was tested six times to determine the intraluminal hydrostatic pressure required to burst the welded seam 1 minute after completing the weld. For the welds made with 107.1, 160.7, and 214.3 J/cm2 in both lasing modes, the mean bursting pressure was 40.7 mmHg (SD +/- 24.9) with no statistically significant difference in weld strengths at these energy densities. There was also no difference between continuous and pulsating delivery methods. However, the energy density of 53.6 J/cm2 in either method produced a mean bursting pressure significantly lower than those produced by the higher energy densities tested and below the estimated basal ileal intraluminal pressure of approximately 9 mmHg. Since 107.1 J/cm2 energy density caused the minimal gross tissue changes while producing an equally strong bond and since continuous is faster than pulsating, 500 mW of continuous delivery was considered the optimal setting for the CO2 laser welding of rabbit ileum.

Animals↗
PubMed1986

Hematoporphyrin derivative fluorescence: photographic techniques for the localization of malignant tissue.

Three simple methods for the detection of malignancy by the photography of hematoporphyrin derivative (HPD) fluorescence are presented. Two methods employ a single lens reflex camera with macrolens and Kodak high-speed Ektachrome (EL 400) film. Both employ a Corning Glass #3482 filter as a barrier on the lens. In method I, a single Kodak Wratten #39 filter is placed over a fluorescent "black light" source (two General Electric F20T12BL 20-W bulbs). In method II, twin electronic flash units (5,500 BCPS unfiltered) with a double thickness of Kodak Wratten #39 filter over them provide the light of excitation. Method III employs an adapted Polaroid SLR 680E Sun camera with two electronic flash units (5,500 BCPS, total unfiltered) rigged with a slave trigger. A Corning Glass #3482 filter is placed on the lens to act as a barrier, and two filters of Kodak Wratten #39 glass are placed on each flash unit. Photographs are taken in a darkened room.

Animals↗