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Biomedical subjects

J O Naim

Publications and source records attributed to J O Naim.

At least 37 records · Page 2Linked to original sources
PubMed1994

Expression of growth factors in early wound healing in rat skin.

Growth factors are a group of hormone-like polypeptides that have been shown to play a central role in different phases of wound healing. The expression of these growth factors in early wound healing has not been quantified, and the pattern and distribution of these growth factors in early wound healing has not been described completely. Furthermore the quantity and pattern of distribution of these growth factors have not been investigated in early wounds produced by various methods of surgical incision. Comparison of the rate of healing between the CO2 laser wound and the scalpel wound has produced conflicting results. The present immunohistochemical study uses polyclonal antibodies specific for epidermal growth factor (EGF), platelet-derived growth factor (PDGF), transforming growth factor beta (TGF-beta), and basic fibroblast growth factor (bFGF) to observe the pattern and distribution of these growth factors in rat skin wound and elucidate whether there are differences in the expression of these growth factors which might account for the delayed healing of the CO2 laser wounds compared to the scalpel as has been observed by some authors. Our results indicate that EGF, TGF-beta, PDGF, and bFGF are expressed and distributed in same areas of the early skin wound. The area of expression of these growth factors was associated with presence of wound inflammatory cells and wound fibroblasts.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute-Phase Reaction↗
PubMed1994

Preliminary assessment of the Con-Bio laser in vivo.

A variety of lasers are available for the treatment of pigmented and vascular lesions. This paper presents our preliminary evaluation of the Q-switched 532 nm Con-Bio laser (Continuum Biomedical, Livermore, CA) in a murine model. Mice were anesthetized with intraperitoneal pentobarbital. Laser impacts (10 nsec, 150 mJ max.) were created on the ears at fluences of 1.5, 2, 3, 4, 5, and 6 J/cm 2. Acute study animals were sacrificed 15 min postinjury. Tissues were fixed in formalin and examined via light microscopy. Chronic study animals were allowed to heal for 3 weeks postoperatively. Parameters analyzed included the presence or absence of blistering, hemorrhage, visual assessment of thermal injury, microscopic evidence of vascular coagulation, or disruption and cosmesis. Acute vascular disruption and coagulation were present in all samples. Healing and cosmesis were good at all fluences tested. Tests of the laser in a prefocused mode produced a tissue cavitation effect with a depth of coagulation of 0.73 +/- 0.44 mm and hemorrhage of 0.68 +/- 0.41 mm. A chronic study of the vascular effect on larger vessels (1-2 mm) was conducted on a rabbit ear. Acute disruption was observed, however, all vessels were recanalized when examined grossly and histologically at 3 weeks. These preliminary results suggest that this new laser may be useful for the treatment of cutaneous vascular lesions. Further studies and clinical trials are warranted.

Animals↗
PubMed1994

The effect of laser irradiation on the release of bFGF from 3T3 fibroblasts.

Studies have shown that low-level laser irradiation increases the proliferation of fibroblasts in cell culture. The mechanism of action is unknown. Basic fibroblast growth factor (bFGF) is a multifunctional polypeptide that has been detected in most tissues and which supports cell proliferation and differentiation. The purpose of this study was to determine whether laser irradiation (660 nm) can stimulate production of bFGF from fibroblast cells in cell culture. Our study showed that fibroblasts irradiated with laser energy at 2.16 J/cm2 demonstrated increased cell proliferation and enhanced production of bFGF, whereas fibroblasts irradiated with laser energy at 3.24 J/cm2 neither demonstrated increased cell proliferation or an enhanced release of bFGF as compared to the control group. These results provide direct evidence that the proliferation of fibroblasts as a result of stimulation by low level laser irradiation may be associated with the autocrine production of bFGF from fibroblasts.

3T3 Cells↗
PubMed1993

Reduction of postoperative adhesions to Marlex mesh using experimental adhesion barriers in rats.

Polypropylene mesh (Marlex) is commonly used to reinforce the abdominal wall during hernia repair. Recently, hernia repair has been performed using laparoscopic techniques. Marlex used for reinforcement is placed directly onto the peritoneum (i.e. transperitoneal) in some repairs. This practice of placing Marlex mesh directly onto the peritoneum may, however, lead to clinically significant bowel adhesions. This study tests whether three different adhesion barriers (Gore-Tex, Interceed, and poloxamer) can reduce bowel adhesion formation when placed directly over the fixed Marlex mesh in the rat. Interceed and poloxamer significantly reduced adhesion formation to Marlex mesh. Gore-Tex had the greatest amount of adhesion formation but this was not significantly different from Marlex control. Poloxamer treatment appeared to significantly reduce tensile strength and Marlex mesh incorporation. The Interceed treatment also appeared to reduce tensile strength as compared to Marlex alone, however, this difference was not significant. The use of Marlex mesh with an Interceed barrier reduces intraabdominal adhesions while not reducing the tensile strength of the Marlex mesh incorporation.

Abdominal Muscles↗
PubMed1993

The adjuvant effect of silicone-gel on antibody formation in rats.

The extent of immunological adjuvancy of silicone-gel, from mammary implants, up to now, has not been determined definitively. This study compares the immune potentiation effects of silicone-gel with that of Freund's adjuvant, using bovine serum albumin (BSA) as the test antigen in rats. Sixty, 250 gr., male Sprague Dawley rats were divided into six groups: I- phosphate buffered saline (PBS) only, II- silicone oil (Dow Corning Medical Grade 360 liquid silicone), III- 50% silicone-gel (McGhan Medical Corp.- mammary implant) in silicone oil, IV- complete Freund's adjuvant (CFA), V- incomplete Freund's adjuvant (IFA), and VI- 50% silicone oil in IFA. Each adjuvant was mixed or emulsified with an equal volume of 50 micrograms of BSA in 150 microliters of PBS. Each immunization was given intramuscularly in a single injection. Cardiac puncture test bleeds were taken at 12, 22, 40 and 56 days post immunization and the serum anti-BSA-antibody was measured by ELISA. The results indicate that silicone-gel is a potent immunological adjuvant, compared to both CFA and IFA. Silicone oil alone is not as potent as adjuvant and seems to inhibit the immune response when mixed with IFA. There thus appears to be a distinct possibility that silicone-gel may also be able to mediate an auto-immune reaction.

Animals↗
PubMed1992

Augmentation of the systemic host anti-tumor response through laser excision.

This study examines whether primary laser excision results in augmentation of the systemic host anti-tumor response to tumor rechallenge. Single R3230AC mammary tumor implants, (0.5 x 0.5 x 1.0 mm), were grown in 112 female Fisher 344 rats. The animals were randomized. Group S tumors were excised by scalpel. Group E was excised with a Surgistat electrocautery (Valley Labs, Boulder, CO). Group CS was excised with a Sharplan 1100 CO2 laser (Sharplan, Allendale, NJ) at 25 watts (W) continuous wave (CW) (0.2 mm spot size) and the wound was "sterilized" with a 5-mm spot size by gently heating the tissue without blanching. Group K was excised with a KTP/532 laser (Laserscope, San Jose, CA) at 17 W CW using a 400 microns fiber. Group Y was excised with a Sharplan 2100 Nd:YAG laser set at 15W CW using a 0.2 mm clear sapphire tip. A second tumor implant, (0.5 x 0.5 x 1.0 mm), was placed at a remote site 14 days postoperatively. An unoperated control group was implanted. Secondary tumor volumes were measured for 36 days and the mean tumor volumes (MTV) were statistically compared. The MTV in groups CS, K, Y, and E was less than control (P less than 0.01). The MTV in groups CS, K, Y, and E was less than group S, although this was not statistically different. Lasers and cautery appear to increase the host response against subsequent tumor challenge. This study corroborates earlier studies of other modalities. Further studies to determine whether this host sensitization is an immune response and to elucidate the mechanisms of this effect are warranted.

Animals↗
PubMed1992

The effect of Nd:YAG laser-induced hyperthermia on local tumor recurrence in experimental rat mammary tumors.

The influence of Nd:YAG laser hyperthermia (45 degrees C for 20 min) on local tumor recurrence followed by CO 2 laser or scalpel excision was studied on 150 F344 female rats that were implanted with R3230AC mammary tumor in the mammary ridge. The development of local tumor recurrence was observed for 39 days postoperatively. All groups undergoing CO 2 laser excision showed a significant reduction in local tumor recurrence (p less than 0.05) compared with the scalpel technique. Animals that underwent CO 2 laser excision and wound sterilization 48 h following laser hyperthermia demonstrated the lowest recurrence when compared with scalpel excision (p less than 0.01). These results indicate that the local thermal effect achieved by laser hyperthermia or laser sterilization plays an important role in the reduction of local tumor recurrence and augments complete local tumor resection.

Aluminum↗
PubMed1992

The effect of hydrophilicity-hydrophobicity and solubility on the immunogenicity of some natural and synthetic polymers.

The general effects of solubility and hydrophobicity-hydrophilicity on the immunogenicity of synthetic and natural polymers are presented. The degree of hydrophobicity or hydrophilicity was determined from contact angle measurements. The surface tension components, obtained from the contact angles, were then correlated with the degree of immunogenicity for each substance. The results indicate that highly hydrophobic and highly hydrophilic polymers are not immunogenic. Moderate hydrophobicity as well as moderate hydrophilicity, and solubility in water favor immunogenicity (provided the molecular mass be at least 10,000 Da). For example, the solubilization of zein (a hydrophobic insoluble maize protein) prior to immunization causes zein to become immunogenic.

Animals↗
PubMed1991

The generation of antibody in mice to tuftsin: a naturally occurring phagocytosis stimulating tetrapeptide.

Tuftsin (Thr-Lys-Pro-Arg) is a naturally occurring tetrapeptide that stimulates most known functions of the polymorphonuclear leukocyte and macrophage cell lines. We previously reported our unsuccessful attempts to generate antituftsin antibodies by conjugating tuftsin to several carrier proteins and by polymerizing the peptide with glutaraldehyde. To render tuftsin antigenic the following modifications were made to native tuftsin: three glycine residues were added to the N terminus of tuftsin (Gly3-tuf) and cysteine was added to the N terminus (Cys-tuf) and to the C terminus (tuf-Cys). Native tuftsin was covalently conjugated to sheep red blood cells (SRBC). In a separate experiment Balb/c mice primed with SRBC were immunized with 10(7) SRBC peptide conjugate. Native tuftsin and Gly3-tuf were also conjugated to keyhole limpet hemocyanin (KLH). In another experiment KLH and cationized bovine serum albumin (cBSA) were activated with sulfo-succinimidyl 4-(N-maleimidomethyl)cyclohexane-1-carboxylate (s-SMCC), which was used to control orientation of tuf-Cys and Cys-tuf when conjugated to each carrier protein. All conjugates were administered in complete Freund's adjuvant (CFA) except for cBSA conjugates which were administered in alum. Antibody response was determined by solid phase radioimmunoassay. Results showed that specific antituftsin antibodies were elicited only by Cys-tuf, conjugated to KLH. This study reaffirms that tuftsin is weakly antigenic and confirms the previous work by Gottlieb et al. that antibody to tuftsin can only be elicited when tuftsin is conjugated to the carrier protein KLH in a manner that leaves the peptide carboxyl end free.

Amino Acid Sequence↗
PubMed1990

Methods for the endoscopic photographic and visual detection of helium cadmium laser-induced fluorescence of Photofrin II.

Endoscopic detection of small tumors is key to the early diagnosis and treatment of malignancy. This paper describes a simple, endoscopic detection system which enables tumor localization and a permanent record based on the laser-induced fluorescence of dihematoporphyrin ether (LIFD). Spectral analysis of dihematoporphyrin ether (DHE, Photofrin II) was performed with a Perkin Elmer LS-5 scanning fluorimeter. DHE at concentrations of 50 micrograms/ml and 5 micrograms/ml in 95% ethanol were tested, demonstrating fluorescence quenching at 50 micrograms/ml DHE at 406 nm excitation. This phenomenon was not observed at 442 nm excitation. Based on this data and the availability of the helium cadmium laser, a series of endoscopic detection systems was developed and tested utilizing a LiConix 4240NB helium cadmium laser (TEMoo, 442 nm, 40 mW). A fiber with a microdiverging (MDL) lens was used. Irradiance achieved at the tip of the fiber was 31.58 mW/cm2 for MDL. A Corning 34832 (550 nm) sharp cutoff barrier filter was coupled to an Olympus OES BF2T10 bronchoscope. Successful detection of LIFD was obtained. Direct observation of LIFD is possible when wearing Laserguard argon safety goggles (OD 15 at 488 nm, OD 11 at 514 nm). Photographic recording of LIFD was performed with the following cameras and parameters: Olympus OM-2S camera (OM2) with EES135 film (ISO 1600) with a 4-second exposure (method 1) and the Olympus OES SCP-10 instant camera with Polaroid 779 (ISO 640) film and a 120-second exposure (method 2). The photographic methods demonstrate the red fluorescence of DHE on filter paper disks at concentrations of 0.5 micrograms/ml (500 ng/ml). (ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
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

The lack of antigenicity of tuftsin: a naturally occurring phagocytosis stimulating tetrapeptide.

Tuftsin (Thr-Lys-Pro-Arg) is a naturally occurring tetrapeptide that stimulates all known functions of the polymorphonuclear leukocyte and macrophage cell lines. Tuftsin is located in the FC region of IgG between the 289 and 292 amino acid sequence of the CH2 domain. We describe unsuccessful attempts to generate antituftsin antibodies. In separate experiments tuftsin was chemically conjugated to methylated bovine serum albumin (CH3BSA), BSA, keyhole limpet hemocyanin (KLH) and purified protein derivative (PPD). Tuftsin was also polymerized with glutaraldehyde. Animals used for immunization were rabbits, roosters, and dogs. All experiments failed to produce antituftsin antibody. Probable reasons for the lack of antigenicity include: I) Lack of "foreignness" of tuftsin in mammal species. II) The small size of the tetrapeptide. III) Tuftsin may be exerting an adjuvant effect when coupled to foreign antigens and is therefore not recognized by the host immune system.

Animals↗
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

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↗