Noam Kariv

Temperature controlled CO2 laser welding of soft tissues: Urinary bladder welding in different animal models (rats, rabbits, and cats)

Laser welding of tissues is a method of closure of surgical incisions that, in principle, may have advantages over conventional closure methods. It is a noncontact technique that introduces no foreign body, the closure is continuous and watertight, and the procedure is faster and requires less skill to master. However, in practice, there have been difficulties in obtaining strong and reliable welding. We assumed that the quality of the weld depends on the ability to monitor and control the surface temperature of the welded zone during the procedure. Our objective was to develop a “smart” fiberoptic laser system for controlled temperature welding.

Leukergy in inflammatory bowel disease

In the phenomenon of leukergy, white blood cells agglomerate in peripheral blood slides. This agglomeration has been described in inflammatory infections of various causes. This study assesses this phenomenon in inflammatory bowel disease. A correlation was found between the severity of inflammatory bowel disease activity and the percentage of leukergy. Leukergy was found to parallel the clinical and endoscopic findings of inflammatory bowel disease. Furthermore, leukergy was found to be more accurate than white blood count and erythrocyte sedimentation rate. It is also found to accurately assess the course of the disease when clinical and other laboratory tests were masked by steroid and antibiotic administrations Leukergy is a quick, inexpensive test that can easily be performed at the patients bedside.

Castration prevents calcium channel blocker-induced gingival hyperplasia in beagle dogs

1 The purpose of this study was to investigate testosterones role on the calcium channel antagonist oxodi-pine-inducing gingival hyperplasia in a dog model. 2 Two experiments were conducted using castrated and intact male dogs. Oxodipine was administered orally for 90 days, at a dose of 24 mg/kg/day. In the first experiment, the occurrence of gingival hyperplasia was evaluated. In the second, the gingival index (GI) and gingival hyperplasia index (GHI) were recorded and correlated with serum levels of testosterone. 3 A significant positive correlation between GI, GHI and plasma testosterone was noted. Castrated dogs were injected with testosterone, 4 months after the start of oxodipine treatment, while in the non-castrated dogs, administration of oxodipine was stopped. Castration correlated with lack of GH, while testosterone injection to the same dogs was associated with an increase of GI and GHI. 4 Since it is known that testosterone receptors are present in the gingiva, it is proposed that oxodipine-induced gingival hyperplasia could be mediated by the calcium channel blocker on plasma testosterone levels.

Efficacy of orally administered deferoxamine, activated charcoal, and sodium bicarbonate in acute iron intoxication in rats: implications for the treatment of pediatric iron poisoning

Abstract Background: Iron supplements are the most frequent cause of pediatric fatalities from unintentional ingestion. The ability to prevent iron absorption from the digestive tract is limited. Although activated charcoal (AC) alone does not absorb iron, the oral administration of deferoxamine (DFO) and AC has been shown to reduce iron absorption in human volunteers. In the presence of sodium bicarbonate (NaHCO 3 ), ferrous iron is oxidized to ferric iron. Therefore, the coadministration of DFO, AC, and NaHCO 3 may enhance enteral iron chelation. Objective: The purpose of the study was to determine whether the oral administration of DFO and AC, with or without NaHCO 3 , can reduce iron absorption from the digestive tract. Methods: In a rat model of acute iron overloading, ferrous sulfate (FeSO 4 ) 100 mg/kg body weight was administered by gavage, followed by DFO 150 mg/kg, AC 500 mg/kg, and NaHCO 3 1 mEq/kg. Results: The administration of FeSO 4 100 mg/kg increased serum iron concentrations to > 350 μg/100 mL. Oral dosing with DFO and AC (separately and simultaneously, immediately or after 10 to 20 minutes) did not prevent iron absorption from the digestive tract. Subsequently, however, DFO significantly decreased the elevated serum iron concentrations ( P 3 further decreased ( P Conclusions: Although orally administered DFO and AC do not prevent iron absorption from the digestive tract, DFO does increase the rate of iron excretion from the body, and NaHCO 3 enhances this effect.

In-vivo CO2 laser rat urinary bladder welding with silver halide fiber optic radiometric temperature control

Laser welding has been used for connecting various tissues in the body. In urology such welding has the advantage of forming an immediate water tight seal. We have developed a fiberoptic system that makes it possible to monitor and control the temperature of the tissue during welding. In previous work we demonstrated that this system could be successfully used to weld punctures in the urinary bladder of rats. It was found that optimal welding was obtained at a temperature of 55 degree(s)C. In this work we used the same system for welding of large openings (cystotomy) in the urinary bladder of rats. In early experiments we used stay sutures and decompressing catheters. It was later found that complete closure can be obtained with CO2-laser welding alone. This work demonstrates the feasibility of using temperature controlled laser welding as an efficient surgical tool.

Esophageal Incisions Repair by CO2 Laser Soldering

PURPOSE: This study evaluated the feasibility of fiberoptic CO2 laser soldering for the repair of esophageal injuries under tight temperature feedback control in an animal model. Healing was compared to conventional suture closure. MATERIALS AND METHODS: A CO2 soldering system equipped with infrared transmitting silver halide fibers was used. The soldered tissue temperature was monitored continuously, and laser power was adjusted to provide constant temperature. The procedure was done with 50% bovine serum albumin solder. Longitudinal incisions measuring 8 to 10 mm were made under general anesthesia in the cervical esophagus of 25 rats. Twenty rats (group I) underwent laser tissue bonding; 8 of which were tested in a preliminary study to determine optimal laser parameters. In the remaining 5 rats (group II, controls), closure was performed with 1 layer of 6/0 Vicryl sutures. The rats were sacrificed 2, 3, 4, and 6 weeks postoperatively, and the esophagus was examined histologically. RESULTS: Optimal temperature was found to be 65 to 70° C and optimal exposure time, 150 to 200 seconds. Laser soldering was successful in 9 of the 12 rats (75%) treated under optimal settings; suturing was successful in 4 of the 5 control rats (80%). There were no significant differences between the groups in healing or complication rates. CONCLUSIONS: These results indicate that the CO2 laser soldering technique is a valid option for the correction of esophageal tears or incisions in rats. The confirmation and extension of these findings in further studies with larger animals may ultimately lead to the routine in vivo use of temperature-controlled laser repair for the esophagus and other organs. This method lends itself to endoscopic bonding of tissues.

Temperature controlled CO 2 laser soldering of pig cornea

Objectives: To determine the feasibility and reproducibility of laser soldering of cornea using biolog ical solder and a fiberopitc temperature conrolled CO2 laser system. Methods: We developed a system based on IR fiber delivery of CO2 laser radiation, for heating a spot on tissue, a fiberoptic radiometer for non-tactile infrared thermometry of the heated spot, and a computer control of the temperature of the spot.Experiments were performed in vivo in 8 corneas of 12Kg piglets eyes, which had 180°, 6mm diameter corneal trephnation perforating cuts.Soldering was done on some of the cuts at a set temperature of 65°C, with adjuvant 47% albumin solder, and standard suturing was done on other cuts, as control.Macroscopic and histologic evaluation was then carried out. Results: On macroscopic examination, the corneas were centrally clear, with corneal neovascularisation only around the sutures.Histologic examination of piglets corneas one week, one month, two months and five months after soldering revealed stromal lamellae which were organized with a fewer inflammatory reaction, in contrast to marked inflammatory response in the suture controls. Conclusions: The laser soldering technology appears to be reliable for closure of large corneal perforating cuts, and may overcome some of the technical difficulties and disadvantages of conventional corneal suture technique.

Laser soldering of the cornea in a rabbit model using a controlled-temperature CO2 laser system

This study was to determine the feasibility and reproducibility of laser welding of cornea with a CO2 laser system capable of real times infrared fiberoptic radiometric control of tissue temperature. A fiberoptic radiometric temperature control system for the CO2 10.6 micrometers laser was developed that enabled a real time nontactile temperature measurement of welding surface. The system was tested on the cornea in 40 in vitro bovine eyes, and also in 6 in vivo corneas of rabbit eyes. Welds performed at a set point temperature of 65 degree(s)C, with or without adjuvant 50% albumin solder. Leaking pressure, surgical time and histologic evaluation were determined for welding and for suturing controls of 6 mm central corneal perforating cuts.

CO2 Laser Welding of Corneal Cuts with Albumin Solder Using Radiometric Temperature Control

Purpose: To examine the efficacy and reproducibility of CO2 laser soldering of corneal cuts using real-time infrared fiber-optic radiometric control of tissue temperature in bovine eyes (in vitro) and to evaluate the duration of this procedure in rabbit eyes (in vivo). Methods: In vitro experiment: a 6-mm central perforating cut was induced in 40 fresh bovine eyes and sealed with a CO2 laser, with or without albumin soldering, following placement of a single approximating nylon suture. A fiber-optic radiometric temperature control system for the CO2 laser was used. Leaking pressure and histological findings were analyzed and compared between groups. In vivo experiment: following creation of a central perforation, 6 rabbit eyes were treated with a CO2 laser with albumin solder and 6 rabbit eyes were treated with 10-0 nylon sutures. The amount of time needed for completion of the procedures was compared. Results: In vitro experiment: effective sealing was achieved by CO2 laser soldering. Mean (± SD) leaking pressure was 109 ± 30 mm Hg in the bovine corneas treated by the laser with albumin solder compared to 51 ± 7 mm Hg in the sutured control eyes (n = 10 each; p < 0.001). Mean leaking pressures were much lower in the corneal cuts sealed only with the laser without albumin solder (48 ± 12 mm Hg) and in the cuts sealed only with albumin without laser welding (6.3 ± 4 mm Hg) than in the cuts treated with laser welding and albumin solder. In vivo experiment: mean surgical time was 140 ± 17 s in the laser-treated rabbits compared to 330 ± 30 s in the sutured controls (n = 6; p < 0.001). A histopathological study of the rabbit corneas 1 day after laser soldering revealed sealed corneal edges with a small gap bridged by coagulated albumin. The inflammatory reaction was minimal in contrast to the sutured controls. No thermal damage was detected at the wound edges. Conclusions: CO2 laser soldering combined with the fiber-optic radiometer is an effective, reliable, and rapid tool for the closure of corneal wounds, and holds advantages over conventional suturing in terms of leaking pressure and surgical time.

Laser soldering of rabbit skin using IR fiber optic temperature control system

Laser soldering of tissues is based on the application of a biological solder on the approximated edges of a cut. Our goal was to use laser soldering for sealing cuts in skin under temperature feedback control and compare the results with ones obtained using standard sutures. Albumin solder was applied onto the approximated edges of cuts created in rabbit skin. A fiberoptic system was used to deliver the radiation of a CO2 laser, to heat a spot near the cut edges, and to monitor and control the temperature. Laser soldering was carried out, spot by spot.