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Biomedical subjects

S N Joffe

Publications and source records attributed to S N Joffe.

At least 37 records · Page 2Linked to original sources
PubMed1987

An experimental study of the effects of electrocautery and various lasers on gastrointestinal tissue.

It is possible that in the future, lasers will replace electrocautery in gastrointestinal surgical procedures. Few studies exist that compare the tissue effects of electrocautery with newer laser modalities. In this study, the tissue effects of electrocautery, noncontact Nd:YAG, contact Nd:YAG, and CO2 lasers were studied in the stomach, small bowel, colon, liver, and pancreas in 24 rats. At light microscopic examination, all tissue damage was thermal in nature, irrespective of the modality used. Furthermore, an independent observer was unable to distinguish which method has been used in most tissues. Tissue effects were similar in the stomach, small intestine, and colon after use of all the modalities. The CO2 laser caused slightly less damage than the other methods (p less than 0.05), but with use of this modality, hemostasis could not be achieved in the liver and pancreas. The contact Nd:YAG laser caused moderate damage with excellent hemostasis in all tissue. The noncontact Nd:YAG caused significantly more tissue damage than all other methods (p less than 0.01), especially in the liver and pancreas. The results suggest that the new contact laser system provides an effective method of performing gastrointestinal surgery with especially good hemostatic effects on liver and pancreatic resections.

Abdominal Muscles↗
PubMed1987

Acid reduction by intragastric contact Nd:YAG laser photoradiation in rats.

Gastric acid reduction in the treatment of duodenal ulcers occurs following extragastric vagotomy, antrectomy, or seromyotomy. This study examines the effects of intraluminal LCV and/or pyloric MA using laser photoradiation in Sprague-Dawley rats. Groups were compared to sham-operation and truncal vagotomy with pyloroplasty (TVP) regarding gastric acid secretion, plasma gastrin, pancreatic polypeptide, and histology, including immunocytochemistry for G-cells. All operative procedures reduced acid output (P less than 0.001) both immediately and at 8 weeks, with LCV being more effective than TVP or MA. Moreover, LCV with MA was no more beneficial than LCV alone. Plasma gastrin increased slightly following TVP but not following the LCV group in the acute study, and no difference was seen in the chronic group. Histologically, the depth of laser penetration was optimum with no perforations. Although the G-cells were destroyed following the laser photoradiation, they reappeared in lesser numbers at 8 weeks. Laser photoradiation of the intramural nerve plexuses on the lesser curve of the stomach by intragastric mucosal myotomy is effective in reducing gastric acid and may have a clinical and therapeutic role with flexible fiberoptic gastroscopy.

Animals↗
PubMed1987

Synthesis of neuropeptide Y.

Neuropeptide Y (NPY), a hexatriacontapeptide amide, was synthesized on benzhydrylamine resin. The peptide product obtained by HF treatment contained 63% of the target peptide, NPY. A comparison of the chemical, immunochemical and biological properties of the synthetic peptide with natural NPY indicated that they were identical.

Amino Acid Sequence↗
PubMed1987

Laserthermia: a computer-controlled contact Nd:YAG system for interstitial local hyperthermia.

Contact Nd:YAG laser surgery is assuming a role of greater importance in endoscopic and open surgery, allowing coagulation, cutting, and vaporization with greater precision and safety. A synthetic sapphire probe allows a wider angle of irradiation and diffusion of low power laser energy (less than 5 W) using an interstitial technique for producing local hyperthermia. Sensors placed directly into surrounding tissue or tumor continuously monitor temperature, and a pertinent computer program produces a controlled and stable temperature (e.g., 42 degrees C) over a period of time (e.g., 20-40 min). The Laserthermia system (Surgical Laser Technologies, Inc., Malvern, PA), using the Nd:YAG laser, offers many advantages in the experimental and clinical treatment of carcinoma by local interstitial hyperthermia.

Body Temperature↗
PubMed1986

The effect of indomethacin on muscle and liver protein synthesis and on whole-body protein degradation during abdominal sepsis in the rat.

It has been recently suggested that increased muscle protein degradation during injury or infection is at least partially mediated by the increased production of prostaglandin E2 in muscle, and some have suggested that cyclooxygenase inhibitors might decrease protein loss in injured or septic patients. In these experiments, fractional synthesis rates of mixed muscle and liver protein and whole-body tyrosine flux were measured by constant intravenous infusion of tyrosine labeled with carbon 14 in 17 rats with sham operations and 15 severely septic rats with or without indomethacin treatment (20 mg/kg/d). Fractional synthesis rates in muscle and liver were decreased in late sepsis and were lowest in the septic group receiving indomethacin. Unlike the fractional synthesis rate, which was affected by indomethacin in septic rats only, tyrosine flux was significantly lower in indomethacin-treated rats with sham operations and those with sepsis. Although indomethacin reduced total-body protein breakdown during sepsis, it was also associated with lower plasma albumin levels and with decreased protein synthesis in muscle and liver at a time when the survival of the septic host may be dependent on its ability to produce new protein for a variety of vital functions. These results do not support the use of indomethacin in sepsis.

Abdomen↗
PubMed1986

Effects of Nd:YAG laser photoradiation on intra-abdominal tissues: a histological study of tissue damage versus power density applied.

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.

Abdomen↗
PubMed1986

Contact neodymium:YAG laser surgery in gastroenterology: a preliminary report.

Fifty-four patients have been successfully endoscopically treated without complications using contact neodymium:YAG laser probes (endoprobes) for tumors and bleeding and, during open surgery (laser scalpel), for liver and pancreatic resections. The contact probes made from a synthetic sapphire crystal with its optical properties, geometric design, and thermal conductivity have proven to be more effective than the current conventional noncontact method of delivering laser energy through a quartz fiber. Advantages include greater precision, sterilizability, avoidance of the tip melting, and a requirement for lower neodymium:YAG laser energy with reduced tissue damage. The configuration of the probes allows coagulation, cutting, or vaporization, depending on the clinical condition being treated.

Adult↗
PubMed1986

Liver resection. A comparison using the Nd-YAG laser, an ultrasonic surgical aspirator, or blunt dissection.

Before gaining wide acceptance, possible surgical tools should be compared with the standard ones. This study, therefore, compared the Nd-YAG laser and the CUSA with the standard blunt dissection technique for liver resection in 24 dogs (8 in each group). Using a noncontact technique, the Nd-YAG laser was used for cutting as well as coagulation. The Nd-YAG laser or the CUSA reduced the resection time, with the laser being the faster of the two, and was accompanied by a probable but not significant decrease in perioperative blood loss. The CUSA delineated the blood vessels and bile ducts and gave superior control. It also caused significantly less tissue damage on light and electron microscopic examination than the other two methods. Cultures taken 1 week after operation showed that the risk of bacterial infection correlated well with the extent of tissue necrosis and was significantly greater after use of the Nd-YAG laser than after use of the CUSA. The numbers of animals are small and the conclusions should be tempered by caution, but it appears that the CUSA, but not the Nd-YAG laser, may improve the results of elective liver resection.

Animals↗
PubMed1986

Effects of micellar oleic acid on canine jejunal blood flow and neurotensin release.

The purpose of this study was to evaluate the role of neurotensin in the local regulation of the lipid-induced jejunal hyperemia. Total blood flow and the arteriovenous hormone concentration difference were measured in isolated jejunal loops of anesthetized dogs with either saline, bile (10% in normal saline), oleic acid (40 mM in normal saline), or oleic acid and bile in the lumen. The bile-oleic acid mixture produced a sustained increase (+25 +/- 3%) in jejunal blood flow, whereas neurotensin release reached a maximum (1.14 +/- 0.34 pmol X min-1 X 100 g-1) 2 min after initiation of the response and then returned to control. Venous neurotensin concentrations also reached a maximum (51 +/- 17 pmol/l) at 2 min. There were no significant changes in either blood flow or neurotensin release in response to the other test solutions. Intra-arterial infusion of neurotensin did not significantly decrease jejunal vascular resistance (-12 +/- 3%) until venous concentrations of 478 +/- 101 pmol/l were attained. It seems unlikely, then, that neurotensin plays any role in the regulation of the lipid-induced jejunal hyperemia.

Animals↗
PubMed1986

Resection of the liver with the Nd:YAG laser.

Controlled studies of experimental hepatic resection have shown noncontact Nd:YAG techniques to be superior in hepatic resection when compared with conventional finger-fracture or ultrasonic aspirator, although tissue damage was extensive. The noncontact technique is compared with the contact technique of hepatic resection (25 to 30 per cent) in male Wistar rats (n equals 60) using a specially designed artificial sapphire laser scalpel attached to the optic fiber. Contact required only low power ranges (5 to 25 watts) for a rapid hepatic lobe resection associated with less bleeding and smoke. Noncontact resection at low power (10 to 20 watts) caused uncontrollable bleeding leading to death whereas in power density ranges greater than 30 watts, successful resection of a lobe of the liver could be done, but as the power increased, there was greater tissue damage. Light microscopy showed laser penetration of 0.5 to 1.0 millimeters with the contact method with evidence of healing, fibrosis and minimal necrotic material at 15 days. In the noncontact group, laser penetration was 2 to 4 millimeters in depth with accumulated necrotic material encapsulated by fibrous tissue at 15 days. Contact hepatic resection with the laser scalpel offers many new advantages than conventional noncontact Nd:YAG laser techniques.

Animals↗
PubMed1985

Use of Nd:YAG laser in pancreatic resections with duodenal preservation in the dog.

The trend in recent years for treatment of pancreatic carcinoma and occasionally for pancreatitis has been towards total pancreatectomy. The pancreas is also now being harvested for transplantation. Any operative technique that can reduce operating time, blood loss, and associated morbidity and mortality would be of tremendous advantage. The aim of this study was to undertake a total pancreatectomy using the Nd:YAG laser (wavelength 1,060 nm) with a helium neon laser (wavelength 628 nm) incorporated to provide a marker beam. The laser beam was passed into a 400 micron flexible glass fiber enclosed in a 2.5 mm polyethylene cannula, which also served as a conduit for coaxial CO2. The laser was operated in a continuous wave mode, and the fiber exit beam had a divergence of 10 degrees. For photocoagulation and tissue vaporization, peak powers of 50 W were used with 0.5-1 sec pulses. The total pancreatectomy using the Nd:YAG laser was performed in eight dogs, and ten dogs undergoing the conventional operative procedure served as controls. The findings indicate that the Nd:YAG laser could be used effectively and safely. The operating time was considerably diminished (P less than 0.01); the number of ligatures used was smaller; blood loss, graft survival, and duodenal viability were similar. The Nd:YAG laser offers a new therapeutic modality in the performance of tedious and often difficult pancreatic surgery.

Animals↗
PubMed1985

Postoperative enteral versus parenteral nutritional support in gastrointestinal surgery. A matched prospective study.

The effects of an elemental-enteral diet administered by a needle catheter jejunostomy or central total parenteral nutrition were prospectively studied in 15 patients undergoing abdominal operations. Infusions were started 1 day after operation and continued for 7 to 10 days. The two nutrient modalities were matched to deliver equal amounts of nitrogen and calories. Both promoted positive nitrogen balance and preserved body weight and serum proteins (albumin, transferrin, thyroxine-binding prealbumin, and retinol-binding protein). Both enteral and parenteral nitrogen caused a similar increase in plasma insulin levels. Pancreatic glucagon, total glucagon, gastrin, and pancreatic polypeptide were also maintained at similar levels in both groups. Plasma vasoactive intestinal polypeptide levels declined in patients receiving total parenteral nutrition but remained stable in the patients who were fed enterally. Both routes caused modest, inconsequential elevations in liver enzymes, but were otherwise equally safe. Patients tolerated total parenteral nutrition far better in the early postoperative period. Patients whose needs are great are probably better treated by total parenteral nutrition. Needle catheter jejunostomy feeding, however, is much less expensive. These studies do not support the commonly held belief that enteral nutrition is a more efficient route for administration of calories and protein.

Adult↗
PubMed1985

Release of secretin immunoreactivity from the ileum.

In the rat, about 80% of the intestinal content of secretin immunoreactivity is found distal to the duodenum with a peak in the ileum. This work therefore studied whether the secretin immunoreactivity in distal ileum could be released by substances normally found in the intestinal lumen. An isolated loop of ileum or duodenum was perfused with 100 mM HCl, 3 mM HCl, 50 mM taurocholate, 50 mM oleate, 308 mM glucose, 273 mM amino acids, or 308 mM NaCl in anesthetized rats. Release of secretin immunoreactivity was estimated by the integrated response above basal in portal blood. Substantial release of secretin immunoreactivity was seen after both ileal and duodenal perfusion with concentrated HCl and taurocholate, whereas perfusion with oleate was followed by a lesser response. The response to taurocholate was slower than that to HCl, but more likely represents a physiologic mechanism. The results show that the distal small intestine is capable of contributing to secretin immunoreactivity in the circulation and it is speculated that bile salts and secretin constitute parts of a negative feedback loop.

Animals↗
PubMed1985

Vasoactive intestinal polypeptide, cholecystokinin, glucagon, and bile-oleate-induced jejunal hyperemia.

The purpose of this study was to evaluate the roles of vasoactive intestinal polypeptide (VIP), cholecystokinin (CCK), and glucagon in the local regulation of the lipid-induced intestinal hyperemia. Total blood flow and the arteriovenous hormone concentration gradient were measured in isolated jejunal loops of anesthetized dogs with either saline, bile (10% in normal saline), oleic acid (40 mM in normal saline), or oleic acid and bile in the lumen. The bile-oleic acid mixture increased both blood flow (+21 +/- 7%) and VIP release (+118 +/- 7%), while CCK release was considerably less. There was a transient rise in glucagonlike immunoreactivity but no change in pancreatic glucagon release. Neither bile nor oleic acid alone altered either local blood flow or hormone release. Infusion of VIP into the arterial circulation of the jejunum significantly reduced vascular resistance (-11 +/- 4%) but at a dose (150 ng . min-1 X 100 g-1) 10 times that released in response to the bile-oleic acid mixture. This study indicates that oleic acid increases both blood flow and intestinal hormone production only when present in the lumen in micellar form and suggests that VIP could play a role in the jejunal vascular response to fat.

Animals↗
PubMed1985

Gastrin and gastric secretion in patients with recurrent peptic ulceration--unexpected correlations.

The role of gastrin in the pathogenesis of recurrent peptic ulceration is not established although it is known that plasma gastrin levels are frequently elevated after vagotomy. This study aims to determine whether there is a relationship between gastrin and gastric secretion in patients with and without recurrent ulceration after surgery for duodenal ulceration (DU). The basal acid output (BAO) in 23 and the peak acid output to pentagastrin (PAOPg) in 10 patients with symptomatic recurrent ulcers after DU surgery were determined along with the BAO and PAOPg in 10 control patients who were asymptomatic following DU surgery. The fasting plasma gastrin was determined in all patients and correlated with the acid output. An inverse correlation was demonstrated between the BAO and plasma gastrin in the asymptomatic patients (p less than 0.05) and the patients with proven recurrent ulcers (p less than 0.01) and there was a direct correlation between the PAOPg and plasma gastrin in the recurrent ulcer group (p less than 0.05) which was not observed in the control group. It is suggested that in a subgroup of recurrent ulcer patients 'G cell hyperfunction' may occur and this may have a role in the aetiology of this condition.

Adolescent↗
PubMed1985

Glucagon, secretin and vasoactive intestinal polypeptide immunoreactivities in rat gut after jejuno-ileal bypass and resection.

Jejuno-ileal bypass (JIB) and resection are associated with hyperplastic and other changes in residual functional gut. In studies on endocrine changes, circulating hormone levels are usually measured. In this study with Sprague-Dawley rats, glucagon, secretin and vasoactive intestinal polypeptide (VIP), immunoreactivities were measured in extracts of gut tissues including formerly adjacent segments of functional and bypassed jejunum and ileum. Young adult (200-220 g) and mature (404-440 g) rats received greater than 90% JIB. Though slight differences were observed in the response of the young and old rats to the operations, and between the effects of JIB and resection, the results do not indicate major involvement of secretin, VIP or gut glucagon-like immunoreactivity in the effects of surgery. Changes include increased immunoreactivity of secretin in the upper and of VIP in the lower functional gut following JIB. N-terminal-to central glucagon immunoreactivity in the functional ileum did not change substantially after operations, but was significantly lower in the non-functional than functional ileum after bypass. Plasma levels of this immunoreactivity were higher following operations and highest following resection.

Age Factors↗