Release of immunoreactive serotonin into the lumen of the feline gut in response to vagal nerve stimulation.

Immunoreactive serotonin was detected in the lumen of the proximal jejunum of food-deprived cats. During perfusion of this intestinal segment in vivo, there was a constant basal rate of intraluminal secretion of this amine. The rate of secretion was significantly increased during efferent electrical stimulation of the cut cervical vagal nerves. This stimulatory effect was not altered after bilateral adrenalectomy was performed in the same animals. A synchronous release of substance P into the gut lumen was also demonstrated during vagal stimulation. During the period of increased intraluminal secretion of immunoreactive serotonin, there was no demonstrable change in the portal or systemic blood levels of this amine.

Prostaglandin A compounds as antiviral agents.

Prostaglandins of the A series strongly inhibit the production of Sendai virus in African green monkey kidney cells and are able to prevent the establishment of persistent infection ("carrier" state). This action is specific for prostaglandin A and is not due to alteration in the host cell metabolism or in the virus infectivity. The possibility that this effect is mediated by interferon is discussed.

Radioimmunoassay for prostaglandins.

Antibodies to prostaglandin were obtained by immunization of rabbits with PGA(1), PGA(2), and PGE(1), protein conjugates of prostaglandins. The antibodies demonstrated specificity toward both the cyclopentane ring and the aliphatic side chains. With the use of these antibodies a highly sensitive radio-immunoassay capable of measuring less than picomolar amounts of PGA1, PGA2, and PGE1 has been developed.

Is thymosin action mediated by prostaglandin release?

Treatment of spleen cells derived from adult thymectomized mice with thymosin fraction 5 resulted in a rapid and dose-dependent stimulation of the release of immunoreactive prostaglandin E2. The release of prostaglandin E2 was associated with induction of theta antigen and was totally inhibited by indomethacin. In contrast, prostaglandin E2 release from spleen cells from intact donors was inhibited by treatment with fraction 5. The data support the concept that prostaglandin E2 mediates the effects of thymosin fraction 5 on lymphocytes.

Radioimmunoassay measurement of prostaglandins E, A, and F in human plasma.

The details of a radioimmunoassay capable of measuring as 5 pg of prostaglandin A, E, and F (PGA, PGE, and PGF) in human and rat plasma are described. Plasma samples are extracted (with 4000 cpm [(3)H] PGE(1) added for calculation of recovery) with an organic solvent system at an apparent pH of 5.8 and then chromatographed on silicic acid columns with increasing concentrations of methanol to separate PGA, PGE, and PGF. Each chromatographed sample is measured by radioimmunoassay, using the homologous antibody and tritiated marker. 40 normal individuals had mean plasma concentrations of PGA, PGE, and PGF of 1062+/-107 pg/ml, 385+/-30 pg/ml, and 141+/-15 pg/ml, respectively. Elevated PGE levels were measured in the plasma of patients with medullary carcinoma of the thyroid, carcinoid, and neuroblastoma. Treatment of rats with indomethacin decreased serum PGE levels by 67%. The radioimmunoassay appears to be of considerable experimental as well as clinical interest.

Local regulation of blood flow in the feline jejunum. A possible role for endoluminally released substance P.

Serotonin and substance P of gastrointestinal origin have been measured by radioimmunoassay in the bowel lumen under basal and stimulated conditions. To investigate the possibility that local blood flow may be influenced by these endoluminal hormones, 26 cats were studied with exogenous serotonin and substance P infused endoluminally into isolated proximal jejunal segments in vivo. Regional blood flow was measured by using the radioactive microsphere technique before, during, and after the endoluminal instillation of two doses of substance P (3.9 and 30 ng/min) or serotonin (0.9 and 21 micrograms/min). Neither dose of substance P changed systemic blood pressure. Substance P at the low dose caused an increase in blood flow to the experimental jejunal mucosa (from 53 +/- 10 ml/min per 100 g to 102 +/- 20 ml/min per 100 g, P less than 0.01). The higher dose of endoluminal substance P similarly increased blood flow to the experimental jejunal mucosal fraction, and also increased blood flow to the experimental jejunal muscularis fraction (from 17 +/- 3 ml/min per 100 g to 23 +/- 3 ml/min per 100 g, P less than 0.02). Serotonin increased blood flow to the experimental jejunal muscularis only at the high dose (17 +/- 4 ml/min per 100 g to 25 +/- 4 ml/min per 100 g tissue, P less than 0.01). These results provide evidence for a dose-related local effect of endoluminal substance P on gastrointestinal blood flow.

Meal-stimulated release of methionine-enkephalin into the canine jejunal lumen.

Application of enkephalins to the luminal surface of the bowel augments intestinal absorption. However, to date, endogenous enkephalins have not been demonstrated within intestinal luminal fluid. To determine whether enkephalins are present in the intestinal lumen, five adult dogs had 25-cm chronic jejunal Thiry-Vella loops constructed. Dogs were studied in the awake, fasted state. Jejunal loops were perfused with isoosmotic, neutral Krebs buffer containing protease inhibitors. After basal sampling, the dogs received a high fat meat meal. Collections were made during the meal and for 60 min postprandially. Luminal met-enkephalin levels were determined by radioimmunoassay and confirmed by HPLC. HPLC separation of luminal samples demonstrated two immunoreactive peaks which co-eluted with pure met-enkephalin and met-enkephalin-sulfoxide. Basal met-enkephalin outputs averaged 52 +/- 13 ng/min. The meal significantly increased mean luminal met-enkephalin output to 137 +/- 71 ng/min. During the initial 20-min postprandial period, output remained elevated (180 +/- 73 ng/min), after which it returned to basal levels. We conclude that met-enkephalin is present in the jejunal lumen, and that luminal release of this opioid is augmented by a meal.

Inhibition of B-16 melanoma growth in vivo by a synthetic analog of prostaglandin E2.

The effect of systemic administration of 16,16-dimethyl prostaglandin E2-methyl ester (di-M-PGE2) on the growth of B-16 melanoma tumors has been studied in C57BL/6J mice. Daily i.p. injection of 5 mu of di-M-PGE2 commencing on the day of tumor inoculation with 10(5) and 10(6) viable cells delayed appearance of tumors; for the smaller tumor inoculum, it also increased median survival among treated mice from 23 to 33 days. Di-M-PGE2 treatment of mice with established tumors caused significant inhibition of tumor growth, as measured by a number of parameters including tumor diameters and volumes. At the time of sacrifice, di-M-PGE2-treated mice had tumors that were an average of 32% smaller (by weight), contained 60% fewer melanoma cells, and had higher concentrations of cyclic adenosine 3':5'-monophosphate and cyclic guanosine 3':5'-monophosphate (+225% and +100%, respectively).

Acromegaly and Cushing's syndrome associated with a foregut carcinoid tumor.

We report an 18-yr-old youth with a metastatic foregut carcinoid tumor, Cushing's syndrome, and hypersomatotropic gigantism. Administration of cyproheptadine caused a dramatic fall in urinary cortisol excretion and plasma ACTH levels associated with clinical remission of the Cushing's syndrome. GH secretion was not affected by cyproheptadine administration. Ectopic ACTH secretion was confirmed by RIA of tumor extracts and immunohistochemical demonstration of ACTH-containing cells in hepatic metastases. There were two sources of GH production demonstrated in this patient. Ectopic secretion of GH by the carcinoid hepatic metastases was documented by both RIA and immunohistochemical techniques. A somatotrophic pituitary tumor was also present. The histological characteristics of this tumor suggest adenomatous hyperplasia rather than de novo neoplastic change as the likely mechanism of its pathogenesis. GH releasing factor-like activity was demonstrated in extracts of plasma and in extracts of the carcinoid tumor. We conclude that cyproheptadine exerted an effect on the ectopic ACTH-producing cells but not on the ectopic GH-producing cells or on adenohypophyseal GH secretion. Production of a GH releasing factor-like activity by the carcinoid tumor may have caused the pituitary somatotrophic tumor.

The gastrointestinal tract as an endocrine organ.

During the past several years gastrointestinal endocrinology has expanded its scope. Several specific clinical syndromes can be directly ascribed to abnormalities in the control of the gastrointestinal hormones. New concepts interrelating the gut and the brain have served as a stimulus for investigation of the interactions among control mechanisms in all aspects of human biology. The rapid, almost explosive progress in this area has been spearheaded by surgical physiologists, for which Dr. Graham would have been justly proud. Finally, it is important to spotlight the role that Washington University researchers have played in this developmental process.

Effect of transplantation on tissue levels of substance P, vasoactive intestinal polypeptide, and serotonin in rat small intestine.

Denervation of the gut, resulting in altered bowel function, has been viewed as an impediment to the clinical success of small intestinal transplantation. This study examined the effect of complete extrinsic denervation of the jejunum and ileum on tissue levels of VIP, SP, and 5-HT in a rat model of small intestinal transplantation. Orthotopic total small bowel isograft transplants were performed in 18 Lewis inbred rats. Sham operations consisted of occluding the superior mesenteric artery of 18 Lewis rats for 10 minutes to provide comparable degrees of ischemia. Six rats from each group were sacrificed 1, 2, and 4 weeks following transplantation or sham operation. The jejunum and ileum were removed and extracted in acid for measurement of VIP, SP, and 5-HT by radioimmunoassay. There were no statistically significant differences in the jejunal or ileal content of VIP or 5-HT or the jejunal content of SP between the transplant and sham groups. An initial decrease in ileal SP content at 1 week following transplantation was no longer evident by the fourth week. We conclude that the extrinsic denervation of small intestinal transplantation has minimal effects on the intestinal content of VIP, SP, and 5-HT and should not significantly affect physiologic function controlled by these gastrointestinal hormones.

Complications of thyroid surgery performed by residents.

The purpose of this report is to study the incidence of complications in thyroid surgery performed by the residents in a surgical training program. This is a report of complications in 200 consecutive thyroidectomies performed by residents with attending surgeons' assistance. There were 128 female and 72 male patients, ranging in age from 16 to 89 years. Ten patients had undergone previous thyroid surgery. There were 40 total thyroidectomies, 38 subtotal thyroidectomies, and 122 lobectomies with isthmusectomy. Preoperative and postoperative evaluation of the vocal cords was a standard routine. Identification of the recurrent laryngeal nerve was routine except in patients with large goiters, who underwent intracapsular subtotal thyroidectomy. An attempt was made to identify and preserve all four parathyroid glands. Even in lobectomy procedures, the ipsilateral parathyroids were identified and preserved. Parathyroid autotransplantation into the sternomastoid muscle was performed in thirteen instances, whenever any of the parathyroids was devascularized. Complications included superior laryngeal nerve palsy (one case) and temporary recurrent laryngeal nerve palsy (one case). There was only one patient in whom temporary hypoparathyroidism developed. In three patients hematomas developed in the recovery room and reexploration was required. Two diabetic patients had wound infections develop that required drainage. Seromas and minor wound collections were noted in 6% of the patients. The incidence of major postoperative complications of thyroidectomy is low, even when residents are the primary surgeons. Thyroidectomy appears to be a safe operation in the hands of residents with close supervision and assistance by the attending surgeons.

Completion thyroidectomy: a critical appraisal.

BACKGROUND: Completion thyroidectomy can most accurately be described as reexploration of the neck to remove the contralateral thyroid lobe. This procedure has commonly been performed when the histopathologic condition of the ipsilateral thyroid lobe reveals papillary or follicular carcinoma of the thyroid. Because of a definitely increased risk of complications with completion thyroidectomy, avoiding its routine use is important. The purpose of this paper is to define the specific indications for completion thyroidectomy. METHODS: Over the past 9 years, we have performed 400 thyroidectomies; the patients ranged in age from 18 to 88 years. Although we have routinely used preoperative needle biopsy and intraoperative frozen section, decisions regarding the extent of thyroidectomy have been based on the gross findings at operation, taking into consideration such prognostic factors as patient age, tumor grade and size, the presence of extracapsular spread or distant metastasis, and associated risk factors. The minimal procedure for solitary thyroid nodule has been lobectomy with isthmusectomy. If the contralateral lobe is grossly normal, lobectomy with isthmusectomy has also been the maximal operation in most of patients. Very few specific indications exist for removal of the opposite lobe. RESULTS: Only three patients underwent completion thyroidectomy. All three patients had aggressive follicular carcinoma requiring radioactive iodine ablation, and all were referred after the initial surgery. We have not performed completion thyroidectomy on any of the patients on whom we initially operated. CONCLUSIONS: The most common indication considered for completion thyroidectomy is a frozen section diagnosis of a benign follicular adenoma that is subsequently changed on permanent pathologic condition to follicular carcinoma based on the presence of capsular and/or vascular invasion. However, if minimal invasion has occurred, no difference exists in survival related to the extent of the thyroidectomy. Local recurrence in the contralateral lobe occurs in less than 10% of the time. Because completion thyroidectomy carries more risks, it should be avoided in most patients when possible. The definitive decision should be made during the initial operation based on gross findings, prognostic factors, and frozen section, and this plan should only be changed to mandate completion thyroidectomy in select circumstances.

Acute airway distress due to thyroid pathology.

Patients with multinodular goiter or related thyroid disorders rarely have acute airway distress due to tracheal deviation or compression. However, our institution cares for a large number of patients with untreated multinodular goiters, and in the progression of this disorder, tracheal deviation and airway problems are relatively common. During the past 4 years, we have cared for 24 patients who were admitted with acute, life-threatening airway distress that required emergency intervention. Nine patients had emergency intubation, the remaining 15 had stridor on admission and underwent emergency operations. The series consists of 19 females and five males whose ages ranged from 37 to 89 years. Only four patients had malignant thyroid lesions (two papillary-follicular, two anaplastic), and two of these had multiple pulmonary metastases. Fifteen of the patients with multinodular goiters had a mediastinal extension that led to marked tracheal deviation. Three patients had recurrent multinodular goiters decades after previous surgery. Twenty-one patients underwent surgery at our institution, and all did well. Only one patient required sternotomy for thyroidectomy. Two patients required tracheostomy procedures, one because of tracheomalacia and the other because of poor pulmonary reserve. Interestingly, two patients had acute symptoms when in their third trimester of pregnancy. We have routinely used the laryngoscope (fiberoptic rigid or flexible) for preoperative and postoperative evaluation of the vocal cords and for determination of the condition of the larynx. On the basis of our experience with acute airway distress, we strongly advocate elective surgery for patients with multinodular goiter at the first sign of tracheal compression, especially if they have mediastinal extension.

The effects of cyclosporine on varying segments of small-bowel grafts in the rat.

The relationship between the cyclosporine A (CSA) dose and rejection of varying lengths of small-bowel grafts was studied in a rat heterotopic microsurgical small-bowel transplantation model involving a haploidentical strain combination. When Lewis X Brown Norway F1 hybrid (LBN) small-bowel grafts were transplanted into Lewis (LEW) rats without CSA, all grafts in the proximal 10 cm, the proximal 40 cm, and the entire (approximately 80 cm) small bowel were rejected on days (mean +/- SEM) 6.6 +/- 0.2 (n = 11), 7.0 +/- 0.4 (n = 6), and 7.8 +/- 0.7 (n = 6), respectively. A 10-day course (days 0-9) of CSA 2 mg/kg significantly (p less than 0.05) prolonged the survival of the proximal 10 cm, the proximal 40 cm, and the entire small bowel allografts to days 18.8 +/- 1.7 (n = 5), 16.5 +2- 1.3 (n = 6), and 13.5 +/- 1.0 (n = 4), respectively. Similarly, the CSA 5 mg/kg regimen significantly (p less than 0.05) delayed the rejection of the 10 cm, the 40 cm, and the 80 cm small-bowel grafts to days 50.2 +/- 7.2 (n = 6), 47.7 +/- 2.6 (n = 3), and 40.3 +/- 5.8 (n = 3), respectively. However, 6 of 12 rats treated with CSA 5 mg/kg died of pneumonia, and these animals were all in groups with the 40 cm and 80 cm grafts. When these animals were included in calculations of rejection-free survival, the averages for the 40 and 80 cm groups treated with CSA 5 mg/kg were 34.2 +/- 6.4 and 28.7 +/- 6.1 days, respectively. CSA suppressed rejection of small-bowel allografts in a dose-related fashion. More important, significantly (p less than 0.05) lower doses of CSA were necessary for rats that received shorter intestinal grafts. In fact, the relationship between rejection and CSA dose in the 10 cm grafts was characterized by the formula: day of rejection = 9.3 [CSA dose]1.03. We conclude that the ideal small intestinal graft should be the smallest possible segment that maintains adequate nutrition and CSA doses should be matched for segment lengths.

The effects of size and site of origin of intestinal grafts on small-bowel transplantation in the rat.

This study was initiated to evaluate the effects of varying the length and site of origin of small-intestine transplants on rejection and on graft-versus-host disease (GVHD). Eighty rats had heterotopic transplants performed with systemic venous drainage of the grafts. The host native bowel was left in situ and no immunosuppressive agents were used. Twenty male Lewis inbred (LEW) rats who received isogenic grafts survived without any evidence of rejection or GVHD. When intestine from Lewis X Brown Norway hybrid rats (LBN) was transplanted into LEW rats, rejection occurred between day 6 and 9 and the time of onset of rejection was not influenced either by the length of transplanted bowel (10 to 80 cm, n = 6 each) or by whether the graft was from the jejunum or the ileum. However, rates of survival for 100 days from rejection were significantly better if 10 cm (100%) or 20 cm (84%) was transplanted than if the grafts were 40 cm or more in length (56%). The LBN recipients of LEW allografts developed GVHD on days 7 through 9, and this response was similarly unrelated to the length or segment of bowel transplanted. However, host survival was quite dependent on graft segment length and site of origin. All animals who received 20 cm or less of proximal bowel survived (with GVHD but no evidence of rejection). While 50% of the animals that received proximal intestinal grafts 40 cm in length survived GVHD, none who received identical-sized grafts from the distal ileum survived (all were dead by day 20). Our data document that the results of small-intestine transplantation is dependent on the length and site of origin of the grafts.

Effect of a synthetic analogue of PGE2 on exocrine and endocrine pancreatic function in the rat.

The effect of 16,16-dimethyl PGE2-methyl-ester (di-M-PGE2, a long-acting synthetic analogue of PGE2) on exocrine and endocrine pancreatic secretion was studied in rats with chronic pancreatic fistulas. Under basal conditions as well as after stimulation with secretin and OP-CCK, pancreatic exocrine secretion was inhibited markedly by intravenous injection of di-M-PGE2 at 10 microgram/kg and 100 microgram/kg. Secretory volumes and bicarbonate and protein outputs decreased within 10 minutes after the administration of di-M-PGE2, and this inhibitory effect persisted throughout the following 40 minutes. The smaller dose of di-M-PGE2 (10 microgram/kg) inhibited the volume of pancreatic secretion by an average of 47.7% and decreased bicarbonate and protein output by 41.1% and 70.5%, respectively. The larger dose (100 microgram/kg) caused a mean 48.3% inhibition of pancreatic secretory volume and decreased bicarbonate and protein outputs by 41.7% and 64.5%, respectively. Plasma insulin levels were lowered markedly after injection of di-M-PGE2 under basal conditions (mean inhibition 63.1% by PG-10 and 55.3% by PG-100) as well as after secretin stimulation (mean inhibition 89.5% by PG-10 and 82.4% by PG-100). These observations document that di-M-PGE2 is a potent inhibitor of pancreatic exocrine and endocrine function in the unanesthetized rat. In these actions the PGE2-analogue antagonized the stimulatory effects of both secretin and OP-CCK.

Tissue levels of prostaglandin E following heterotopic rat heart allografting.

Heterotopic rat heart allografts were performed in 35 rats. At intervals after transplantation, rats were killed and tissue concentrations of immunoassayable prostaglandin E (PGE) were measured in the native heart, transplanted heart, spleen, and thymus. A significant increase in allograft PGE activity was observed at days 5 through 7, coinciding with the onset of the rejection reaction. These studies implicate PGE in the host response to allografting, but further studies are needed to determine what (if any) role prostaglandins play in the rejection reaction.

The prostaglandin response to cholesterol feeding by the rabbit gallbladder in vitro.

Eleven rabbits (five female, six male) were fed a high (2%) cholesterol diet for 2 weeks. Twelve control rabbits (six female, six male) were fed standard rabbit chow. As expected, the cholesterol feeding raised serum and bile cholesterol concentrations and increased the lithogenic indexes. The gallbladders were harvested, and the mucosa and serosa were separately exposed to arachidonic acid in an in vitro incubation chamber at 37 degrees C. Cholesterol feeding stimulated the rates of synthesis of PGI2, but this effect was limited to the serosa (and not the mucosa) of gallbladders from female (but not male) animals. In contrast, cholesterol did not induce any changes in PGE biosynthesis.

The effects of short-term ethanol exposure on the canine jejunal handling of calcium and glucose.

The effects of ethanol on simultaneous jejunal handling of calcium and glucose were studied in long-term canine jejunal Thirty-Vella loops. The loops were perfused intraluminally in a random sequence with physiologic buffer, buffer containing 3.5% ethanol, and buffer containing 7% ethanol. The addition of 3.5% or 7% ethanol to the buffer reduced the net absorption of glucose by 13% and 26%, respectively. The addition of 7% but not 3.5% ethanol significantly increased the net secretion of calcium (168% of basal). In contrast, luminal perfusion with ethanol did not significantly alter intestinal handling of water, sodium, or potassium. Serum calcium and glucose levels were similarly unaffected by the ethanol perfusion. Mean serum ethanol levels were all less than 10 mg/dl. We conclude that intraluminal ethanol has a significant effect on the jejunal handling of glucose and calcium, and this effect is not dependent on systemic intoxication.