Biomedical subjects

L B Katz

Publications and source records attributed to L B Katz.

At least 19 recordsLinked to original sources

PubMed1999

Bronchopulmonary segmental lavage with Surfaxin (KL(4)-surfactant) for acute respiratory distress syndrome.

We performed a trial to assess the safety and tolerability of sequential bronchopulmonary segmental lavage with a dilute synthetic surfactant (Surfaxin) in 12 adults with ARDS. Patients received one of three dosing regimens in which aliquots of Surfaxin were administered via a wedged bronchoscope to each of the 19 bronchopulmonary segments. Suctioning was performed 10-30 s after instillation of individual aliquots. Group 1 patients (n = 3) received one 30-ml aliquot of a 2.5-mg/ml concentration of Surfaxin in each segment, followed by a second 30-ml aliquot with a 10-mg/ml concentration. Group 2 patients (n = 4) received two 30-ml aliquots of the 2.5-mg/ml concentration followed by a third lavage with the 10-mg/ml concentration. Group 3 patients (n = 5) received therapy identical to that received by patients in Group 2 and were eligible for repeat dosing 6 to 24 h later. All patients tolerated the procedure. There were no serious adverse experiences ascribed to either the procedure or the surfactant. In the 96 h after treatment initiation, FI(O(2)) decreased from 0.80 to 0.52 and PEEP decreased from 10.3 to 7.6 cm H(2)O. Bronchoscopic "cleansing" of the lungs with dilute Surfaxin may offer a safe and feasible approach to improving outcomes in patients with ARDS. Wiswell TE, Smith RM, Katz LB, Mastroianni L, Wong DY, Willms D, Heard S, Wilson M, Hite RD, Anzueto A, Revak SD, Cochrane CG. Bronchopulmonary segmental lavage with Surfaxin (KL(4)-surfactant) for acute respiratory distress syndrome.

Bronchoalveolar Lavage↗

PubMed1999

The role of surgery in occult gastrointestinal bleeding.

The surgeon is frequently involved in the management of patients with occult gastrointestinal bleeding. It is important to have a systematic approach to these patients to avoid the "looking for a needle in a haystack" approach to this problem. These are a group of patients who have undergone extensive standard gastroendoscopic evaluation and continue to bleed. Five percent of gastrointestinal bleeding occurs between the ligament of Treitz and the ileocecal valve. Therapeutic management may be guided by the age of the patient. Patients aged younger than 50 years will usually bleed from readily identifiable palpable lesions, such as leiomyoma, Meckel's diverticulum, or other small-bowel tumors, whereas the patients aged older than 50 years most commonly bleed from angiodysplasias or arteriovenous malformations that are not palpable, frequently multiple, and may be evanescent.

Age Factors↗

PubMed1995

Laparoscopic resection of two liver hemangiomata.

New laparoscopic instrumentation coupled with standard surgical techniques allows one to perform procedures previously thought impossible via the laparoscope. This report reviews the natural history, the indications for resection, and the technique of laparoscopic resection of hepatic hemangiomata. Two women, 24 and 62 years of age, were first seen with abdominal pain. A diagnosis of hemangioma was made in each case, and both lesions were removed laparoscopically. Operative blood loss was 200 cc in each case, and neither patient required transfusion. Diets were started on the first postoperative day (POD), and the patients were discharged on the second and fourth PODs without narcotic analgesia. If the size and location of the tumor are favorable, laparoscopic resection of liver hemangiomata can be performed safely. Blood loss comparable to that of open procedures and a quicker recovery support an endosurgical approach to resection of liver hemangiomata in selected cases.

Abdominal Pain↗

PubMed1994

Jejunal obstruction as a late result of neonatal jejunal atresia.

The authors report on two adults who had jejunal dilatation after having had resection for jejunal atresia in the neonatal period. Both patients presented 20 years after the initial procedure, with severe iron deficiency anemia, marked jejunal dilatation proximal to the old anastomotic site (which was not narrowed), and a bezoar within the dilated segment. Upper gastrointestinal series were used to evaluate both patients before surgical resection of the enlarged intestine, with subsequent correction of the anemia.

Adult↗

PubMed1993

Novel thieno[2,3-b]- and [3,4-b]pyrans as potassium channel openers. Thiophene systems--XVII.

The syntheses and antihypertensive activity of the thieno[3,4-b]pyran and thieno[2,3-b]pyran isosteres of the potassium channel opener (PCO) RWJ 26629 (+/- 2a) are reported. While the unsubstituted thiophene derivatives were active at 20 mg/kg, introduction of a strong electron withdrawing group in the 2-position of the thieno[3,2-b] series increased potency. Similar substitution on the thieno[3,4-b] series significantly lowered potency. Compounds 26 and 30 are approximately 5-fold more potent than the prototypic PCO cromakalim (+/- 1).

Animals↗

PubMed1993

RWJ 26629, a new potassium channel opener and vascular smooth muscle relaxant: a potential antihypertensive and antianginal agent.

The effects of trans-5,6-dihydro-6-hydroxy-5,5-dimethyl-2-nitro-7-(2-oxopiperidin -1-yl)-7H- thieno[3,2-b]pyran (RWJ 26629) were compared with those of the standard potassium channel opener cromakalim and several standard calcium channel blockers. RWJ 26629 lowered the mean arterial blood pressure in conscious spontaneously hypertensive (ED30 = 10 micrograms/kg p.o. or 8 micrograms/kg i.v.) and renal hypertensive (15 micrograms/kg p.o.) rats, conscious renal hypertensive (ED20 = 4 micrograms/kg p.o.) and normotensive (ED20 = 5 micrograms/kg p.o. or 2 micrograms/kg i.v.) dogs and anesthetized rhesus monkeys (ED20 = 6 micrograms/kg i.v.). RWJ 26629 was more potent than cromakalim and had a maximal activity greater than the calcium channel blockers. At antihypertensive doses, RWJ 26629 had no significant effect on cardiac force, cardiac output, stroke volume or stroke work in dogs and had little or no effect on renal, carotid or femoral blood flow or vascular resistance. RWJ 26629 was also selective for antihypertensive activity in rats compared with its ability to inhibit intestinal motility. However, RWJ 26629 did relax contracted pulmonary smooth muscle in vivo at antihypertensive doses. All compounds tested caused reflex tachycardia in conscious dogs, although this effect was lowest for RWJ 26629. Most importantly, RWJ 26629 potently and selectively increased coronary blood flow with a potency and duration of action greater than that of cromakalim or nifedipine without affecting contractile force. In vitro, RWJ 26629 selectively relaxed precontracted coronary arteries compared with its effect on femoral arteries.(ABSTRACT TRUNCATED AT 250 WORDS)

Angina Pectoris↗

PubMed1992

Thiophene systems. 14. Synthesis and antihypertensive activity of novel 7-(cyclic amido)-6-hydroxythieno[3,2-b]pyrans and related compounds as new potassium channel activators.

The synthesis and antihypertensive activity of novel 7-(cyclic amido)-6-hydroxy-5,5-dimethylthieno[3,2-b]pyrans and related compounds are described. The compounds were tested for oral antihypertensive activity in spontaneously hypertensive rats (SHR) and selected compounds were evaluated in vitro for increases in 86Rb efflux in rabbit isolated mesenteric arteries. The effects on activity in SHR of lactam ring size, the presence of heteroatoms in the lactam ring, the relative stereochemistry at C-6 and C-7, and the substituents on the thiophene ring are examined. The best racemic compound in this series is 32, trans-5,6-dihydro-6-hydroxy-5,5-dimethyl-2-nitro-7-(2-oxopiperidin -1-yl)-5H- thieno[3,2-b]pyran, which is 10-fold more potent than cromakalim with an ED30 = 0.015 mg/kg in SHR. Compound 32 could be resolved and the antihypertensive activity determined to reside primarily in the (6S,7S)-(-)-enantiomer 41. Surprisingly, the elimination of water to give the enamides 50-52, thiophene isosteres of bimakalim, diminishes activity significantly.

Animals↗

PubMed1992

Surgical approach to occult gastrointestinal bleeding.

In 5% of patients with gastrointestinal bleeding, standard evaluation fails to reveal the source of the bleeding. We describe the management of 71 patients treated for obscure gastrointestinal bleeding at the Mount Sinai Medical Center, New York, New York, from 1985 to 1991. There were 38 men (54%) and 33 women (46%). The mean age was 60 years. The patients had bleeding episodes for a mean period of 26 months and required an average of 20 units of blood prior to surgical treatment. All had undergone an extensive diagnostic workup including barium contrast studies, endoscopies, and angiographies. Some had multiple bleeding scans, Meckel scans, and surgical explorations. Three patients were found to have "watermelon stomach" on endoscopy and had an antrectomy. Sixty-eight (96%) patients underwent a preoperative small bowel enteroscopy, which revealed the precise diagnosis in 50 (70%) of the patients. All patients underwent surgery. In 30 (42%) patients in whom the bleeding site was not apparent at exploration, intraoperative enteroscopy was performed. Two actively bleeding patients had intraoperative enteroscopy, which failed to localize the bleeding site, and intraoperative scintigraphy was utilized. The bleeding was found to originate in small bowel arteriovenous malformation (AVM) (28 patients), leiomyoma (8 patients), primary small bowel malignancies (11 patients), and other causes (24 patients). Fifty-six patients (80%) had no further bleeding; 9 with multiple small bowel AVM have experienced rebleeding and are alive. Six patients died of recurrent bleeding, and six died of metastatic cancer. An aggressive approach should be applied in patients in whom standard evaluation fails to localize the source of gastrointestinal bleeding. Enteroscopy, surgical exploration with additional intraoperative enteroscopy, and occasional intraoperative scintigraphy can achieve an excellent yield and allow resection and potential cure.

Algorithms↗

PubMed1990

Liesegang rings in renal cyst fluid.

Peculiar ring-like structures identified as Liesegang rings (LRs) were found in renal cyst fluid from three patients with benign renal cysts. They ranged in size from 5 to 820 mu. Most had a double-layer outer wall with equally spaced radial cross-striations and an amorphous central nidus. Special stains were performed in one case, and the results are discussed. Reports of LRs in cystic or inflamed tissues have recently appeared in the literature. Some LRs have been mistaken for eggs or mature components of the giant kidney worm, Dioctophyma renale. We propose that cytologic assessment of renal cyst fluid in conjunction with histologic examination decreases the likelihood of misdiagnosis of LRs.

Aged↗

PubMed1990

Aspiration cytology of papillary cystic neoplasm of the pancreas.

The authors present a case of papillary and cystic neoplasm of the pancreas (PCN) in which fine-needle aspiration was performed intraoperatively. Only a few reports of fine-needle aspiration of this rare tumor have been published. The features most helpful in reaching a diagnosis of PCN were a monotonous population of tumor cells, round to oval bland-appearing nuclei, scanty to moderate ill-defined cytoplasm, and the presence of numerous capillaries. Despite the lack of branching papillary clusters described in previous reports, it was possible to suggest the correct diagnosis by identifying these other characteristic features. In addition, estrogen and progesterone receptor levels were measured and found to be negligible. A review of the literature with emphasis on cytologic features also is presented.

Adult↗

PubMed1990

Intraoperative scintigraphy for active small intestinal bleeding.

Localizing active sites of bleeding within the small intestine remains a difficult task. Endoscopic, angiographic or scintigraphic studies may point to the small intestine as the site of blood loss, but at operation, without a palpable lesion, the exact site of bleeding remains elusive. Patients are managed at laparotomy with intraoperative endoscopy, angiography, multiple enterotomies, "blind" resections, or placement of an enterostomy. We describe two patients in whom intraoperative scintigraphy accurately identified active sites of bleeding in the small intestine when other modalities failed. Intraoperative scintigraphy is rapid, easy to perform and is an effective means of identifying active sites of bleeding within the small intestine.

Aged↗

PubMed1989

Slow release delivery of rioprostil by an osmotic pump inhibits the formation of acute aspirin-induced gastric lesions in dogs and accelerates the healing of chronic lesions without incidence of side effects.

Rioprostil, a primary alcohol prostaglandin E1 analog, inhibits gastric acid secretion and prevents gastric lesions induced by a variety of irritants in experimental animals. Because rioprostil is relatively short-acting, it would be of significant benefit clinically if its duration of action could be extended to allow once daily dosing. This investigation demonstrates that when administered via an osmotically driven pump (Osmet, Alza Corp.), rioprostil prevents the acute effects of aspirin on the gastric mucosa of dogs, accelerates the healing of aspirin-induced gastric lesions, and heals preexisting aspirin-induced gastric lesions during chronic administration of aspiring. The potency of rioprostil against acute gastric lesion formation was greatest when delivered from a 24-hr release pump (ED50 = 0.77 micrograms/kg/24 hr) and was 37 times greater than when administered as a single oral bolus. In addition, this activity occurred at doses which had little or no gastric antisecretory activity in betazole-stimulated Heidenhain pouch dogs. When delivered from a 24-hr pump, rioprostil (100 micrograms/kg/24 hr) healed preexisting aspirin-induced gastric lesions within 8 days after removal of aspirin, or after 15 days during continued daily aspirin administration. Additional studies determined that administration of rioprostil at doses of 720, 1440, or 2160 micrograms/kg/24 hr (935-2805 times the gastroprotective ED50 in 24 hr pumps) was well tolerated, with only slight, transient increases in body temperature, softening of the stools, and mild sedation at the highest dose. Administration of rioprostil daily for 5 days at 960 micrograms/kg/24 hr from 24-hr release pumps was also well tolerated by all dogs with no evidence of any accumulation of effect of rioprostil. In summary, administration of rioprostil via an osmotic pump increases its potency and duration of action against the gastric lesion-inducing effect of aspirin, and maintains a wide ratio of safety.

Acute Disease↗

PubMed1989

Rioprostil prevents aspirin-induced fecal blood loss in dogs. Correlation of Hemoquant (Hb) with endoscopic findings.

Rioprostil, a primary alcohol prostaglandin E1 analog, prevents gastric lesion formation induced by a variety of irritants, including aspirin, in rats and dogs. In the present study, rioprostil reduced both gastric lesion formation and fecal blood loss in dogs caused by daily aspirin administration (1,950 mg/day) for 3 consecutive days. A gastric antisecretory dose of 100 micrograms/kg p.o. t.i.d. of rioprostil reduced fecal blood loss by 96% to a level (0.76 +/- 0.10 mg Hb/g stool) similar to basal blood loss in non-aspirin-treated vehicle dogs (0.61 +/- 0.08 mg Hb/g stool) as determined by HemoQuant assay. A nonantisecretory dose of rioprostil (1 microgram/kg p.o. t.i.d.) reduced fecal blood loss by 70% compared to vehicle-treated dogs. Gastric lesion severity scores in dogs treated with 100 or 1 micrograms/kg p.o. t.i.d. of rioprostil were 61 and 52% lower, respectively, than the mean severity score in the vehicle-treated group. There was a highly significant (p less than 0.001) correlation between gastric lesion score and fecal blood loss independent of the treatment each dog received. The efficacy of a nonantisecretory dose suggests that the gastric lesion effect of rioprostil may be independent of gastric antisecretory effects. The correlation of fecal blood loss with gastric lesion score suggests the possibility that either measurement may be used as an indication of gastric lesion occurrence or severity.

Animals↗

PubMed1989

Gastric antisecretory and antigastrolesive pharmacology of rioprostil.

Rioprostil, a primary alcohol prostaglandin E1 analogue, inhibits gastric acid secretion, both in vivo and in vitro, and prevents the formation of experimentally-induced gastric lesions in rats and dogs. In vitro experimental evidence suggests that the mechanism of the gastric antisecretory activity of rioprostil involves inhibition of the membrane bound histamine-stimulated adenylate cyclase. In vivo, rioprostil inhibits gastric acid secretion in 4-h pylorus-ligated rats, in gastric fistula dogs stimulated by betazole, tetragastrin, bethanechol, or 2-deoxy-D-glucose, and in Heidenhain pouch dogs stimulated by food. Rioprostil can completely prevent macroscopically visible gastric lesions induced by a variety of noxious agents in rats, including 50% ethanol, aspirin, indomethacin, strong acid, strong base and hypertonic saline. In dogs, rioprostil, but not the H2-blockers cimetidine or ranitidine, totally prevents endoscopically visible gastric lesions induced by aspirin tablets or 60% ethanol, and accelerates the healing of established aspirin-induced gastric lesions from 20 days (vehicle control) to 6 days (33 micrograms/kg p.o., t.i.d.) or 11 days (3 micrograms/kg p.o., t.i.d.). The precise mechanism for the antigastrolesive activity of rioprostil is not known, but may involve increased mucus and bicarbonate secretion, maintaining or increasing gastric mucosal blood flow, increasing the rate of cellular restitution, or possibly antigastrin activity that has been demonstrated in dogs. In rats, rioprostil also prevents duodenal lesions induced by cysteamine, small intestinal lesions induced by indomethacin, and colonic lesions induced by ethanol. The antisecretory and antigastrolesive potency of rioprostil given transdermally to rats is similar to its potency when given systemically, although its diarrhoeagenic potential is lower when given topically compared to oral administration. When used in combination with several non-steroidal anti-inflammatory drugs (NSAIDs) in a model of arthritis in rats, rioprostil inhibits gastric lesion formation without interfering with the anti-inflammatory or analgesic potency of the NSAIDs. In addition, concomitant use of either antacid or cimetidine with rioprostil does not inhibit either the antisecretory or antigastrolesive potency of rioprostil, with the effect of the combination being additive. The doses required to inhibit formation of experimentally-induced gastric lesions in both rat and dog are lower than those required to inhibit gastric acid secretion. This separation of antigastrolesive from antisecretory activity distinguishes rioprostil from other non-prostanoid antisecretory agents, such as histamine H2- receptor antagonists, and establishes rioprostil as a 'selective antigastrolesive agent' (SAGA).(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed1989

Rioprostil heals pre-existing aspirin-induced gastric lesions in dogs during daily aspirin administration without altering the anti-inflammatory or analgesic efficacy of aspirin.

Rioprostil (3-100 micrograms/kg/day p.o.), but not cimetidine (30 mg/kg/day p.o.), healed pre-existing aspirin (1950 mg)-induced gastric lesions in dogs despite daily aspirin (975 mg) administration. Gastric antisecretory doses of rioprostil (10 and 100 micrograms/kg/day) decreased lesion scores by 71 to 77 and 90 to 93% after 7 and 11 days, respectively. A nonantisecretory dose of rioprostil (3 micrograms/kg/day) decreased lesion scores by 80% after 14 days. In contrast, lesion scores in dogs receiving either vehicle or a maximal gastric antisecretory dose of cimetidine (30 mg/kg/day) remained unchanged during the 28-day course of treatment. In addition, rioprostil prevented the weight loss which accompanied daily administration of aspirin (975 mg) in vehicle- or cimetidine-treated dogs. When cimetidine-treated dogs were switched to daily rioprostil (100 micrograms/kg/day) and aspirin (975 mg/day) therapy, lesions healed within 6 days. In separate studies, rioprostil had no effect on the sensitivity of the gastric mucosa to subsequent aspirin administration. In addition, discontinuation of maintenance therapy during rioprostil treatment was of no increased benefit (i.e., lesions did not heal faster). Finally, in a model of urate-induced knee-joint synovitis, rioprostil treatment did not inhibit the anti-inflammatory or analgesic efficacy of aspirin, or have any proinflammatory effect of its own.

Analgesia↗

PubMed1989

Oral KCl dietary supplement extends survivability of dogs with Heidenhain pouch gastric fistulas.

Supplementing the food of Heidenhain pouch gastric fistula dogs with a KC1 product greatly extends the survivability of these dogs. Since there is a continuous discharge of gastric juice from the pouch to the exterior each time a meal is consumed, clinical signs such as dehydration, anorexia, rough hair coat and lethargy usually occur within a few months after gastric pouch surgery and, unless extensive supportive measures are taken, most dogs will die shortly thereafter. The five dogs which did not receive KC1 supplementation died within 6 months after surgery with a mean survival time of 2.4 +/- 0.9 months. Seven dogs that received a daily oral supplement of 1.5 g KC1 (20 mEq) in their food have, on average, survived more than ten times longer than dogs which received no KC1 supplementation, with a mean survival time of 25.1 +/- 4.4 months. All KC1 supplemented dogs survived for more than 15 months with three dogs currently surviving for 36-40 months. When two dogs experienced decreased serum potassium, sodium and/or chloride levels and showed clinical signs of electrolyte imbalance despite receiving daily oral KC1 supplementation, intervention with intravenous (i.v.) lactated Ringer's solution and increased amounts of oral KC1 supplement reversed these symptoms within 1-2 weeks. Dogs that received only i.v. Ringer's therapy died with 1 week of the onset of clinical signs. Daily oral KC1 supplementation, careful observation of behavior and eating patterns, and routine physical examinations and serum electrolyte measurements can greatly extend the life expectancy of dogs with Heidenhain pouch gastric fistulas.

Administration, Oral↗

PubMed1987

Antigastrolesive, gastric antisecretory, diarrheagenic and mucus-stimulating effects in rats following topically applied rioprostil, a synthetic prostaglandin E1 analog.

Prostaglandins may have many biological actions including hypotensive and antipeptic ulcer activity. The purpose of this investigation was to determine if the primary alcohol prostaglandin E1 analog rioprostil1 prevents ethanol-induced gastric lesions (antigastrolesive activity), inhibits gastric acid secretion (antisecretory activity), or causes diarrhea in rats when administered topically, and to compare these responses to the effect of rioprostil following enteral (oral or intraduodenal) administration. Rioprostil exhibited antigastrolesive activity in rats when administered either orally or when applied topically. The topical antigastrolesive potency of rioprostil against ethanol-induced lesions [ED50 = 3.7 (0.5-12) micrograms/kg] was similar to its oral potency [ED50 = 1.9 (1.7-2.2) micrograms/kg]. In 4 hr pylorus-ligated rats, topically administered rioprostil inhibited total gastric acid output with a potency [ED50 = 5.1 (2.6-24) mg/kg] similar to intraduodenal administration [ED50 = 3.7 (2.8-5.3) mg/kg]. In addition, in these rats rioprostil increased mucin levels and did not cause dermal irritation. Finally, the incidence of diarrhea was lower when rioprostil was applied topically than when given orally with a 16-fold difference in potency between these two routes of administration. These data show that when rioprostil is applied via the skin it has antigastrolesive, gastric antisecretory and mucus stimulatory effects in rats equal to enteral administration, and a diarrheagenic potency lower than following oral administration. This profile suggests that topical administration of rioprostil may be a useful means of delivery for clinical treatment of peptic ulcer disease.

Administration, Topical↗

PubMed1987

Antisecretory and antigastrin effects of rioprostil in gastric fistula dogs.

This investigation examined the effect of rioprostil, a primary alcohol prostaglandin E1 analog, on betazole-stimulated gastric acid secretion and on basal and food-stimulated (postprandial) serum gastrin levels in gastric fistula dogs. Rioprostil inhibited betazole-stimulated gastric acid secretion with an ED50 of 16 (10-24) micrograms/kg, intragastrically. A near-maximal gastric antisecretory dose (100 micrograms/kg, intragastrically) had no effect on basal serum gastrin levels but significantly attenuated the rapid rise in serum gastrin which follows feeding, a result different from that reported for other prostaglandin E1 analogs. A nonantisecretory dose of rioprostil (1.0 micrograms/kg, intragastrically) also attenuated the rise in postprandial serum gastrin. An antigastrin effect using a nonantisecretory dose of an antiulcer agent has not been reported previously and may indicate that rioprostil has a direct inhibitory effect on secretion of gastrin. The ability of rioprostil to inhibit gastric acid secretion and decrease postprandial peak serum gastrin levels, coupled with previously established cytoprotective efficacy, makes it an attractive clinical candidate for the treatment and prevention of peptic ulcer disease.

Animals↗