Cloning and sequencing of the pancreatic islet neogenesis associated protein (INGAP) gene and its expression in islet neogenesis in hamsters.

Induction of islet neogenesis by cellophane wrapping (CW) reverses streptozotocin-induced (STZ) diabetes. Administration of Ilotropin, a protein extract isolated from CW pancreata, causes recapitulation of normal islet ontogeny and reverses STZ diabetes, reducing mortality by 50%. We investigated the hypothesis that a novel gene encoding a constituent of Ilotropin was expressed in the hamster pancreas undergoing islet neogenesis. Islet neogenesis associated protein (INGAP) is a product of a novel gene expressed in regenerating hamster pancreas. Northern blot analysis showed a strong single transcript of 850 bp at 1 and 2 d after CW that disappeared by the 6th day and was absent from untreated control pancreata. INGAP gene is expressed in acinar cells, but not in islets. Western blot analysis demonstrated the presence of INGAP in Ilotropin but not in extracts from control pancreata. A synthetic pentadecapeptide, corresponding to a region unique to INGAP, stimulated a 2.4-fold increase in [3H]thymidine incorporation into hamster duct epithelium in primary culture and a rat pancreatic duct cell line but had no effect on a hamster insulinoma tumor cell line. A portion of human INGAP gene was cloned and appears to be highly homologous to the hamster gene. This data suggests that the INGAP gene is a novel pancreatic gene expressed during islet neogenesis whose protein product is a constituent of Ilotropin and is capable of initiating duct cell proliferation, a prerequisite for islet neogenesis.

Induction of nesidioblastosis will reverse diabetes in Syrian golden hamster.

Nesidioblastosis, which is the formation of new islets and the differentiation of cells within the islets, represents part of the spectrum of hyperfunctioning states of the islets of Langerhans at the clinical level. Nesidioblastosis in the Syrian golden hamster can be induced by wrapping the head of the pancreas with cellophane tape. Ligation of the duct is not involved, and acinar cell atrophy does not occur. The purpose of this study was to determine whether the induction of nesidioblastosis could be used as a means of reversing streptozocin-induced diabetes. Outbred hamsters (n = 32), 8 wk of age, were rendered diabetic by treatment with 40 mg/kg i.p. streptozocin, administered daily for 3 days. Four days later, 16 animals chosen at random underwent laparotomy with cellophane wrapping of the pancreas. Before surgery, the serum glucose and insulin levels (means +/- SE) in the unoperated control animals (389.0 +/- 18.6, 33.9 +/- 3.8) did not differ from those in the animals awaiting the operation (373.2 +/- 18.6, 37.9 +/- 3.8). After 7 wk, 50% of the operated animals had serum glucose and insulin levels that were normal, compared to only 12% of the unoperated control animals (chi2 = 5.53, P less than .05). Islets from normoglycemic operated animals were characterized by increased numbers, including many small islets, positive immunoreactive insulin staining, and minimal vacuolation of cells. Islets from hyperglycemic operated hamsters and from the unoperated control animals were decreased in number and generally larger in size, demonstrated little or no immunoreactive insulin staining, and exhibited marked vacuolation of cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Trophic stimulation of the ductal/islet cell axis: a new approach to the treatment of diabetes.

The purpose of this study was to demonstrate that the pancreas of the hamster contains a growth factor(s) that can induce cells associated with the ductular epithelium to differentiate along an endocrine pathway and thereby provide a means of regenerating a functioning islet cell mass. We have shown previously that partial obstruction of the pancreatic duct leads to the induction of nesidioblastosis. A cytosol extract prepared from the partially obstructed hamster pancreas was injected at a dose of 4000 microliters intraperitoneally twice a day for 2 days and produced significant increases in pancreatic weight, protein, and deoxyribonucleic acid of 18%, 18% and 42% respectively, over saline-treated control animals. To assess the effects of this extract on morphology, 150 microliters intraperitoneally twice a day was administered for 21 days. Tissue was processed for histologic, morphometric, and autoradiographic analysis. Budding of endocrine cells from cells of the terminal ductules was observed in cytosol-injected animals and the number of islets per square millimeter was determined to be increased by 100% compared with saline-treated controls (p less than 0.01). Tritiated thymidine uptake by ductal and islet cells was increased tenfold and sixfold, respectively, over that of control animals (p less than 0.01). Cytosol extract was also administered to hamsters rendered diabetic by streptozocin. Survival in these animals was 100% compared with only 60% for saline-treated control animals (p less than 0.05). Furthermore, the blood levels of glucose in cytosol-treated animals was significantly less than the levels in saline-treated controls (p less than 0.05). We conclude that the pancreas does indeed contain a growth factor(s) responsible for the induction of nesidioblastosis and the new islet tissue is functionally capable of stabilizing a diabetic state.

Rational management of malignant colon polyps based on long-term follow-up.

We reviewed the long-term results of management of 38 patients with carcinoma in colorectal polyps. Of these, 16 patients demonstrated malignant invasion of the lamina propria but not the muscularis mucosa (group I), and 22 patients showed malignant invasion of the muscularis mucosa (group II). Primary therapy for group I patients consisted of polypectomy in 12, local excision in one, and colonic resection in three. One patient had a subsequent abdominal-perineal resection and was found to have no residual disease and no lymph node involvement. Follow-up of the group I patients showed that 11 were alive and well (mean 5.8 years) and five died of unrelated causes (mean 5.2 years). Of group II patients, 12 underwent polypectomy, six local excision, and four colectomy. Of these 22 patients, 11 underwent further operation, including nine major bowel resections and two local re-excisions. None of these 11 patients had either residual tumor or lymph node metastases. One patient died of complications after abdominal-perineal resection. Follow-up showed that 18/22 group II patients were alive and well 5 to 15 years later (mean 7.5 years); four died of unrelated causes (mean 3.2 years). We then reviewed another group of 220 patients who had undergone resection for invasive colon cancer to relate the presence or absence of lymph node metastases to the depth of malignant invasion in the bowel wall. We found that 44% of this entire group had lymph node involvement. Of 36 patients with tumor confined to the bowel wall, nodal metastases occurred in only 22%. Of eight patients with malignancy superficial to the muscularis propria, only one had nodal involvement. We conclude that colon cancer tends to progress in an orderly fashion and the risk of nodal metastases increases with the depth of invasion. Carcinoma in a polyp represents a very early stage of colon cancer. We therefore recommend polypectomy as primary treatment for pedunculated polyps containing carcinoma either superficial to or invading muscularis mucosa. If histologic review demonstrates incomplete excision, lymphatic invasion, or poor differentiation, patients with lesions invading the muscularis mucosa should undergo formal colonic resection.

Elemental diet as prophylaxis against radiation injury. Histological and ultrastructural studies.

We investigated whether elemental diet feeding would protect the intestine from radiation injury. Five dogs were fed an elemental diet for three days before receiving pelvic irradiation (500 rad/day for four days) and were maintained on the diet during the days of irradiation. These dogs were compared with five dogs that were fed normal kennel ration, but were treated similarly otherwise. One day and five days following completion of the radiation treatment, the dogs were anesthetized and a biopsy specimen of terminal ileum was taken for histologic and electron microscopic studies. In the dogs fed the elemental diet, there was no significant damage to the intestine seen on histological examination, and electron microscopy disclosed elongated microvilli and no organelle damage. However, both histological and electron microscopic examination of the intestine from dogs maintained on normal kennel ration showed that severe damage had occurred from the irradiation procedure. It seems, therefore, that the feeding of an elemental diet to dogs as a prophylaxis can afford protection to the intestine from the acute phase of radiation injury.

The effect of cellophane wrapping of the pancreas in the Syrian golden hamster: autoradiographic observations.

We examined the effects of cellophane wrapping of the pancreas on the age-related uptake of tritiated thymidine (3H-TdR) by the differentiated cell types of the pancreas of the Syrian golden hamster. Fifty-two hamsters were studied. At 7 weeks of age, hamsters underwent cellophane wrapping (n = 32) or were allocated to a control group (n = 20). Animals 8-22 weeks of age (four at each interval) received 3H-TdR (2 microCi/g) intraperitoneally and were killed 1 h later. Pancreatic tissues from each animal was processed for autoradiography. The percent of acinar cells labeled with 3H-TdR at 8 weeks, in control and wrapped animals, was 1.17 +/- 0.26 and 1.51 +/- 0.38 respectively (p = N.S.). In control animals, this steadily diminished to 0.02 +/- 0.00 at 22 weeks. In wrapped animals, there was less of a tendency for acinar cell labeling to decrease with age, and the percent of labeled acinar cells in wrapped animals at 22 weeks was 0.05 +/- 0.00. The percent of ductular cells labeled with 3H-TdR at 8 weeks in control and wrapped animals was 0.24 +/- 0.24 and 0.98 +/- 0.24, respectively (p = N.S.), and at 22 weeks was 0.13 +/- 0.90 and 0.60 +/- 0.03, respectively (p less than 0.01). The percent of islet cells labeled with 3H-TdR at 8 weeks in control and wrapped animals was 0.16 +/- 0.01 and 0.42 +/- 0.01, respectively (p less than 0.05), and at 22 weeks was 0.18 +/- 0.01 and 0.63 +/- 0.05 (p less than 0.05), respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Early changes of gene expression during cerulein supramaximal stimulation.

Administration of supramaximal doses of cerulein results in acute interstitial pancreatitis. To understand the pathogenesis of this disease, it would be of great importance to elucidate the changes during the early phase of the process. We report changes of gene expression in the pancreas during the first 6 h of cerulein supramaximal stimulation. The expression of genes, including the secretory enzyme amylase, the lysosomal enzyme cathepsin B, as well as the housekeeping genes beta-actin and glyceraldehyde-3-phosphate dehydrogenase (GAPD), was investigated in this study. The most prominent alteration in gene expression is beta-actin messenger RNA (mRNA), which increased continuously after cerulein infusion. Immunostaining for beta-actin was observed along the membrane of large cytoplasmic vacuoles in pancreatic acinar cells. The level of amylase mRNA decreased during the first 30 min of cerulein infusion, recovered to the control level at 1 h and increased twofold at 2 h. An obvious increase in cathepsin B mRNA was observed after 3 h of cerulein infusion and reached sixfold of the control at 6 h. A significant increase of GAPD mRNA level was observed at 6 h of cerulein stimulation. In conclusion, this study provides direct evidence that the changes in gene expression, such as cathepsin B and amylase, after supramaximal cerulein stimulation, are regulated at the transcriptional level. It also suggests that beta-actin is involved in the formation of cytoplasmic vacuoles during supramaximal cerulein administration. Finally, this study indicates that beta-actin and GAPD may not be appropriate as RNA-loading controls for Northern blot analysis of pancreatic tissue.

The structural integrity of the islet in vitro: the effect of incubation temperature.

The purpose of this study was to examine the effect of incubation temperature on the structural integrity of the islet during culture. Islets were isolated from the pancreas of the Syrian golden hamster and cultured in a collagen gel for < or =12 days at 24 degrees C or 37 degrees C. At 24 degrees C, cells in the islet periphery died, leading to a complete disintegration of the mantle region in 37.4+/-5.6% of the islets. In comparison, at 37 degrees C, few islets exhibited mantle disintegration (p<0.001). Insulin immunoreactivity was distributed nonhomogeneously in islets at 24 degrees C, and the intensity of the staining, by using a semiquantitative scale (0-3), was +1. Islets cultured at 37 degrees C had a normal homogeneous distribution of insulin immunoreactivity with a score of +3. As the pancreas is a complex gland composed of different cell types, and cell-cell interactions are known to be important in the maintenance of cell survival, additional experiments were repeated to include the coculture of islets with duct epithelial cells. The proportion of islets that developed mantle disintegration was now reduced to 2.5+/-0.3% (p<0.001), comparable to that seen at 37 degrees C. Similar results were obtained for islets cultured in the presence of duct-conditioned medium (DCM). Together with the preservation of the islet mantle, islets cultured in the presence of duct epithelial cells or DCM had a normal homogeneous distribution of insulin immunoreactivity, with a staining intensity of +3. We conclude that incubation temperature has a profound effect on the structural integrity of islets, and that the detrimental effects of low-temperature culture can be mitigated by coculture of islets with secretory products derived from pancreatic ductal cells. These data provide evidence for a trophic relation between pancreatic islets and ductal epithelium.

Pancreatic schwannoma: report of two cases and review of the literature.

Solitary intrapancreatic schwannoma is a rare tumor. We present two patients with this tumor and review 13 previously reported cases from the English-language literature. While the final diagnosis was made based on pathological examination of the tumors, both computed tomography scan and magnetic resonance imaging helped establish the benign nature of the lesion, narrow the differential diagnosis, and define the anatomical locations of the small tumors. Both tumors were treated by enucleation from the surrounding pancreatic parenchyma, and both patients, after 2 years of follow-up, are alive and well. It is concluded that multimodality radiologic investigations are useful in the workup of unusual pancreatic masses. In addition, based on the known biologic behavior of schwannomas occurring elsewhere in the body, simple enucleation, rather than more radical resection, is likely to be adequate therapy for these tumors.

Induction of islet cell differentiation and new islet formation in the hamster--further support for a ductular origin.

Partial obstruction of the adult hamster pancreas leads to islet cell differentiation and new islet formation. From morphologic and morphometric observations, we have tentatively identified the source of the new islet tissue to be from cells in the ducts. In this study, in vivo labeling with a single pulse of tritiated thymidine after partial duct obstruction was used to ascertain whether newly formed islet cells were in fact derived from cells in the ductal epithelium. Supportive evidence for this formulation was also sought using immunocytochemistry for islet hormones and in situ hybridization for glucagon and insulin mRNA to probe areas of proliferating duct cells. Endocrine cell differentiation was observed as a migration of cells out from small ducts beginning at about 10 days after obstruction. Duct and islet cell labeling indices (LI;%) in control animals remained at a low level (0.25 +/- 0.01 and 0.26 +/- 0.03, respectively) throughout the experiment. In contrast, at 2 weeks after partial obstruction, the duct and islet cell LI were 4.2 +/- 0.7 and 0.80 +/- 0.1 (p < 0.05 vs. control). After 2 weeks, there was a rapid and significant 86% decline in the duct cell LI to a low of 0.6 +/- 0.2 at 8 weeks, which was accompanied by a comparable, but reciprocal, 113% increase in the islet cell LI to a high of 1.7 +/- 0.8 (p < 0.05). In situ hybridization demonstrated glucagon and insulin mRNA-positive cells within intralobular ducts as early as 6 and 8 days, respectively, after obstruction. Glucagon and insulin peptides appeared in these cells at approximately 8 and 10 days, respectively, as cells migrated out from the duct wall. This study provides additional evidence that further supports our concept that pancreatic endocrine cell differentiation in this model reiterates the normal ontogeny of beta cell differentiation from cells in the ductular epithelium.

Alterations in pancreatic microcirculation and expression of endothelin-1 in a model of chronic pancreatitis.

Chronic pancreatitis (CP) is characterized by the presence of an inflammatory infiltrate with progressive destruction of acinar cells and fibrosis. The finding that endothelin-1 (ET-1), an endothelium-derived peptide having vasoconstrictive and mitogenic properties, reduces pancreatic blood flow (PBF) in normal rats suggested that the peptide may be associated with the reduced PBF seen in animal models of CP and with the morphological abnormalities of the disease. This study investigates changes in blood flow to the pancreas and other abdominal organs in a rat model of CP and compares ET-1 production in the pancreata of these rats and normal controls. CP was induced in male Wistar rats by the injection of oleic acid into the common bile/pancreatic duct. The radiolabeled microsphere technique was employed to measure blood flow to the pancreas, duodenum, liver, spleen, and kidneys. Immunohistochemistry was used to investigate the cellular production of ET-1. After 3 weeks, significant decreases were noted in body weight, pancreatic weight, and pancreatic DNA, amylase, and protein content in the animals with CP. PBF was reduced by 64% and duodenal blood flow by 80% relative to those in control animals. Hepatic and splenic blood flows were increased by 91 and 88%, respectively, compared to those in controls. A 50% decrease in renal blood flows were increased by 91 and 88%, respectively, compared to those in controls. A 50% decrease in renal blood flow was also seen in the experimental group after 3 weeks. Pancreata from animals with CP stained diffusely for ET-1 in the cytoplasm of vascular endothelial, acinar, and ductal cells. In the control pancreata, focal staining for ET-1 was observed only in acinar cells. This difference was significant in endothelial and ductal cells. There was weak staining of islet cells in both groups. The results suggest that elevation in local production of ET-1 may be associated with the morphological and hemodynamic changes of CP.

Neurotropic malignant melanoma of right temple with orbital metastasis: a clinicopathological case report.

A case is reported of neurotropic melanoma developed from a superficial spreading melanoma with minimal cytological deviation, situated in the right temple. The nine-year course was clinically characterised by local recurrences, involvement of the orbit and the parotid region via neurogenic invasion, and systemic metastases to lung, seventh rib, and the brain. The histopathology was characterised by fascicles of dysplastic spindle cells, neuroid arrangement in loose fibrillary matrix, and peri- and intraneural permeation of the nerve trunks. Despite minimal atypism the neoplasm metastasised and had a fatal outcome. The spindle cell component of the neurotropic melanoma lacked melanogenesis; Fontana stains were negative. As previously demonstrated, the histogenesis of the neurotropic melanoma is possibly a Schwann cell differentiation of the dysplastic atypical melanocytes, as shown by the positive reactions to Bodian's stain.

Development of experimental cancer in the head of the pancreas by surgical induction of tissue injury.

The majority of carcinomas of the pancreas in humans are of ductal origin and are located in the head of the gland. These clinical characteristics however, are not affected in traditional animal models of the disease. Partial pancreatic duct obstruction with ductal epithelial hyperplasia was produced in the Syrian golden hamster by wrapping the head of the pancreas with cellophane tape. Wrapped and unwrapped animals were then exposed to an exogenous carcinogen (N-nitrosobis[2-oxopropyl]amine). Assay of serum ribonuclease activity was used as a marker of disease. Invasive lesions developed in both groups of animals. Fifty percent of the tumors in the Group II (cellophane wrap and N-nitrosobis [2-oxopropyl] amine) hamsters were located in the head of the gland and were of ductal origin. All tumors in animals receiving N-nitrosobis [2-oxopropyl]amine alone (Group I) occurred peripherally and were derived from ductular or acinar tissue. Elevation of serum ribonuclease activity was noted early in the course of carcinogenesis, thereafter returning to normal, which may explain the clinical controversy regarding this marker. This new model should enhance our knowledge of the interrelationships between etiologic factors, precursor lesions, and pancreatic cancer.

Renal cell carcinoma presenting as nephrotic syndrome complicated by acute renal failure.

A case of minimal change nephropathy occurring in association with a renal cell carcinoma is presented and discussed. The case was unusual in that it was associated with acute renal failure necessitating hemodialysis for five weeks. The renal failure resolved but the nephrotic state persisted in spite of therapy with prednisone then cyclophosphamide. The literature on nephrotic syndrome causing acute renal failure and its association with solid tumors is briefly reviewed.

Extramedullary plasmacytoma of the orbit: case report with results of immunocytochemical studies.

Orbital involvement as the initial manifestation of primary extramedullary plasmacytoma is rare. The case presented in this article illustrates several interesting aspects of the disease. The neoplastic process involved monoclonal B-lymphocytes that produced IgG-lambda chains.