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B C Sheppard

Publications and source records attributed to B C Sheppard.

35 records · Page 2Linked to original sources
PubMed1997

Herbicide/pesticide effects on intestinal epithelial growth.

The purpose of the present study was to examine the effects of some common herbicides and pesticides on the growth of normal intestinal and colonic epithelial cells. Preconfluent cultures of normal rat intestinal cells (IEC-6 cell line) and normal human colonic epithelial cells were treated with 0.05-50 microM doses of atrazine, diazinon, and endosulfan. After 3 days of treatment, the change in cell proliferation was quantified by cell counting or the MTT growth assay. Both intestinal and colonic epithelial cell cultures had increases in cell growth when treated with as little as 1.0 microM atrazine, diazinon, or endosulfan. The observed changes in both cultured intestinal and colonic cell growth rates were not due to the influence of the vehicle control dimethyl sulfoxide (DMSO). That is, the treatment of the cell cultures with concentrations of DMSO as high as 0.5% for 3 days resulted in no change in cell growth compared with untreated control cultures. A consistent observation with all three of the compounds was that the highest doses (50 microM) had the least "proliferative potential" in stimulating either IEC-6 cell or human colonic epithelial cell growth. Within the concentration range used, none of the herbicides or pesticides caused a decrease in cell proliferation below that of the untreated control cultures. Overall, treatment of IEC-6 cell cultures with atrazine, diazinon, or endosulfan produced a biphasic growth response, whereas the same treatment in the human colonic epithelial cell cultures produced a more sustained level of growth over the same period. This culture system may provide the basis for an in vitro model to further study the cellular and molecular basis of the effects of herbicides and pesticides on intestinal epithelial proliferation.

Animals↗
PubMed1996

Establishment of human colonic epithelial cells in long-term culture.

Study of normal colonic function is important in understanding the cellular mechanisms of carcinogenesis and other diseases of the colon. However, colonic pathophysiological studies have been limited due to the lack of long-term cultures of normal human colonic epithelial cells. The purpose of the present study was to develop methods of isolating viable human colonic epithelial cells for the establishment of nontransformed colonic epithelial cell lines. Human colonic epithelial cells were isolated from surgically resected normal human colons. We found that the use of a short enzymatic digestion gave a consistently higher number (>90%) of viable human colonic epithelial cells. These isolated colonocytes were grown on plastic, collagen-coated filters, or feeder layers using different media formulations. Those colonocytes from the initial primary cultures that were most "epithelial" in appearance were cloned and passaged to establish long-term cultures of nontransformed human colonic epithelial cells. The epithelial nature and secretory function of these established cell lines were confirmed by morphological criteria (light microscopy,, phase contrast microscopy, and electron microscopy). We found that the long-term cultures remained immunopositive to anti-cytokeratin antibodies and immunonegative to anti-vimentin antibodies. Using a soft agar assay we found that the colonocytes did not form colonies, suggesting that the long-term culturing did not cause these cells to become transformed. Under serum-free conditions, we found that epidermal growth factor and transforming growth factor-alpha were equally potent in their mitogenic effects for these colonocytes. Some of the subcultured cells could be maintained for at least 8 months and still retain their epithelial characteristics. We believe that this methodology will serve as a valuable tool for the isolation and culturing of human colonic epithelial cells for studies of normal and malignant colonic disease processes.

Agar↗
PubMed1996

Laparoscopic bilateral adrenalectomy following failed hypophysectomy.

BACKGROUND: Laparoscopic adrenalectomy has recently been shown to be a safe and effective means of treating adrenal pathology with much lower morbidity than the traditional approach. The majority of reports in the literature involve removal of adrenal tumors. Although open bilateral adrenalectomy has been utilized for persistent Cushing's syndrome following attempted hypophysectomy, there is little data available describing the application of laparoscopic adrenal surgery to this problem. METHODS: Four patients with persistent Cushing's syndrome after attempted treatment with hypophysectomy underwent laparoscopic bilateral adrenalectomy at our institution. One procedure was done transabdominally in the supine position. Three procedures were done transabdominally using sequential lateral decubitus positions. RESULTS: All procedures were completed laparoscopically. The mean operative time was 4.6 h (range 3.9-5.25). Repositioning and reprepping the patients resulted in a slight increase in operative time, but visualization was improved using the lateral decubitus position. Average blood loss: 156 cc (range 50-300). One patient required early reoperation for bleeding from the left adrenal bed, which was controlled laparoscopically. Three patients were eating the following day and were discharged on postoperative days 1, 2, and 5. The fourth patient remained hospitalized for 18 days due to problems unrelated to surgery. After a mean follow-up of 10 months, all patients have done well and have no clinical or biochemical evidence of recurrent disease. CONCLUSION: Our clinical experience indicates that laparoscopic bilateral adrenalectomy is a viable treatment option for Cushing's syndrome following failed hypophysectomy.

Adrenalectomy↗
PubMed1996

Identification of an EGF/TGF-alpha receptor in primary cultures of guinea pig gastric mucous epithelial cells.

Binding and localization of transforming growth factor-alpha (TGF-alpha) and epidermal growth factor (EGF) were assessed using in vitro primary cultures of guinea pig gastric mucous epithelial cells (GMEC). GMEC were isolated and cultured in six-well plates with Dulbecco's modified Eagle's medium + 10% serum and then changed to serum-free medium for 24 h for binding studies. The binding time course of 125I-labeled EGF and 125I-TGF-alpha in GMEC cultures at 4 degrees C was saturable, reaching a plateau within 4-6 h. Competition-binding curves revealed that the amount of unlabeled EGF and TGF-alpha to reduce 125I-EGF binding by 50% was 0.35 and 0.23 nM, respectively. The amount of unlabeled EGF and TGF-alpha to decrease 125I-TGF-alpha binding by 50% was 0.30 and 0.21 nM, respectively. A Scatchard analysis of the data disclosed that a single class of high-affinity binding sites (dissociation constant = 0.24 nM) was present. The maximal binding capacity was approximately 20 fmol/10(6) cells or approximately 12,000 receptors per cell. The binding of 125I-EGF and 125I-TFG-alpha to GMEC cultures was maximal between pH 7.0 and 8.5. No specific binding of EGF or TGF-alpha could be detected below pH 5.0. The half-maximal pH dissociation value for EGF and TGF-alpha was pH 5.89 and pH 6.83, respectively. We found no difference in the final amounts of membrane-bound or internalized 125I-EGF and 125I-TGF-alpha. However, there was a significant difference (P < 0.05) at 5-30 min in the rate of dissociated and internalized 125I-EGF- and 125I-TGF-alpha. Immunofluorescence microscopy of GMEC cultures for EGF/TGF-alpha receptors showed increased fluorescence at the leading edges and around the perimeter of cells. Detection of an EGF/TGF-alpha receptor was also confirmed by Western blotting. Our findings demonstrate that guinea pig GMEC possess a specific EGF/TGF-alpha receptor, which further supports a physiological role for EFG and TFG-alpha as mitogens in these cells.

Animals↗
PubMed1995

Clostridium difficile colitis: an increasing hospital-acquired illness.

BACKGROUND: Colitis caused by Clostridium difficile is receiving increased attention as a nosocomial hospital-acquired infection. METHODS: To determine the incidence of C difficile colitis in our facility and the relative proportion of patients dying from the colitis or requiring colectomy for it, we retrospectively reviewed 201 cases of colitis caused by C difficile from 1984 to 1994. RESULTS: The incidence of C difficile colitis appears to be sharply increasing and is associated with the use of cephalosporins. Among patients who subsequently developed C difficile colitis, the most frequent indication for antibiotic use was perioperative prophylaxis; surgical patients comprised 55% of the total cases. Surgical intervention was required for 5% of patients with C difficile colitis, with an operative mortality of 30%. The overall mortality was 3.5% and was associated with a delay in diagnosis. The only discriminative factor between patients who died and those who survived was length of time from symptoms to treatment--5.43 days for survivors versus 10.7 days for those who died (P < 0.05). CONCLUSIONS: Most cases of C difficile colitis seen by surgeons have followed the use of perioperative prophylactic antibiotics. Strict guidelines for using perioperative antibiotics should be observed. Prompt recognition of C difficile colitis and aggressive therapy for it are essential for a favorable outcome.

Adolescent↗
PubMed1993

Pulmonary metastatic disease in ameloblastoma.

Ameloblastoma is a rare disease of odontogenic origin with indeterminate metastatic potential. The first site of metastatic disease is usually the lung. We report aggressive surgical treatment of a patient with bilateral disease with five subsequent recurrences. A review of the literature suggests that in the absence of effective chemotherapy or radiation, surgery should be considered the treatment of choice for metastatic ameloblastoma confined to the lung.

Adult↗
PubMed1992

Pulsatile activation of the hypothalamic-pituitary-adrenal axis during major surgery.

To examine the response of the hypothalamic-pituitary-adrenal (HPA) axis to severe surgical stress, we measured the immunoreactive plasma levels of corticotropin-releasing hormone (CRH), corticotropin, cortisol, arginine-vasopressin (AVP), atrial natriuretic factor (ANF), neuropeptide Y (NPY), interleukin-1 (IL-1), IL-6, interferon gamma (INF), and tumor necrosis factor-alpha (TNF-alpha) in eight patients with Zollinger-Ellison syndrome (ZES) or mediastinal parathyroid carcinoma, all undergoing major surgery with a standardized anesthetic technique. Blood samples were drawn the morning before surgery, every 10 to 30 minutes throughout surgery (average, 308.7 +/- 15 minutes), and every morning for the next 4 postoperative days (POD). During surgery, plasma CRH concentrations were slightly but not significantly elevated compared with those before surgery and with those of the next 4 POD. However, the values were within the normal range (less than 2.2 pmol/L) and showed 8.9 +/- 0.6 pulses (one pulse every 34.7 +/- 1.6 minutes). Plasma corticotropin, on the other hand, was quite elevated, but was also released in a pulsatile fashion during the surgical procedure (one pulse every 36.7 +/- 1.6 minutes). Most of these secretory episodes of corticotropin were temporally related to those of CRH. Corticotropin returned to basal levels on the first POD and remained so for all 4 POD. Plasma cortisol concentrations increased steadily during surgery and remained elevated the first POD. Cortisol showed 6.2 +/- 1.1 pulses during the operative sampling period (one pulse every 71.8 +/- 13 minutes). Plasma AVP concentrations were also markedly elevated during surgery, but individual secretory pulses were not detected.(ABSTRACT TRUNCATED AT 250 WORDS)

Cytokines↗
PubMed1991

Treatment with recombinant human tumor necrosis factor-alpha protects rats against the lethality, hypotension, and hypothermia of gram-negative sepsis.

Tumor necrosis factor (TNF) is a peptide secreted by macrophages in response to endotoxin that can produce many of the changes seen in septic shock. After cecal ligation and puncture (CLP) rats gradually develop tachycardia, hypotension, tachypnea, and hypothermia. At 5 h post-CLP, rats have a peak in serum levels of endotoxin and 60% of rats have blood cultures that grow Gram-negative rods (Escherichia coli and Klebsiella pneumonia). At 20 h post-CLP all rats develop positive blood cultures. Serum levels of TNF are not reproducibly measurable in rats following CLP. Rats undergoing CLP have a 50-80% mortality with deaths usually occurring 24-72 h postinjury. Repetitive (twice daily x 6 d) i.p. injection of sublethal doses of recombinant human TNF-alpha (100 micrograms/kg) to rats undergoing CLP 1 d after the treatment period resulted in a significant reduction in mortality compared to control rats previously unexposed to rTNF (P less than 0.03). Animals treated with rTNF had no hypotension or hypothermia after CLP and regained normal food intake faster than control rats. 12 h after CLP the gene expression for manganous superoxide dismutase (MnSOD), an inducible mitochondrial metalloenzyme responsible for cellular resistance to injury from toxic reactive oxygen species, was higher in livers of rats treated with rTNF suggesting that the TNF treatment augmented expression of this protective enzyme. Unlike MnSOD, expression of the gene for copper-zinc SOD was not affected by CLP or rTNF treatment. The results suggest that prior treatment with recombinant TNF can ameliorate the lethality, hypotension, hypothermia, and anorexia of Gram-negative sepsis in rats and that the mechanism may be related to enhanced hepatic expression of the gene for MnSOD. Repeated administration of recombinant TNF may be a strategy to minimize mortality and morbidity of Gram-negative sepsis.

Animals↗
PubMed1991

Tumor necrosis factor and interleukin-1 protection against the lethal effects of tumor necrosis factor.

Based on the hypothesis that tumor necrosis factor (TNF) causes the lethality of gram-negative sepsis and previous work of tolerance to the lethal effects of TNF induced by repetitive exposure to sublethal intraperitoneal doses of human recombinant (r) TNF, we studied the protective role of a single sublethal intravenous dose of either rTNF (100 micrograms/kg) or recombinant interleukin-1 (rIL-1; 10(5) units/kg) or both before a subsequent lethal intravenous dose of rTNF (800 to 1000 micrograms/kg) in C3H/HEN mice. Mice were treated with a single intravenous dose of saline, rTNF, rIL-1 or both cytokines and challenged within 2 hours to 10 days with a lethal dose of rTNF. Mice treated with rTNF showed significant protection against the lethal effects of TNF when the treatment dose was given only 2 hours before the lethal dose, but maximal protection required a 24-hour interval and lasted as long as 8 days. The treatment dose of rTNF was toxic, and it resulted in occasional treatment deaths. Mice treated with rIL-1 showed maximal protection when treatment was given only 2 hours before challenge and protection lasted for 8 days. No toxicity was apparent secondary to IL-1 treatment. The combination of rIL-1 and rTNF was not as effective as either cytokine alone. The results suggest that rTNF or rIL-1 may be clinically useful in the prevention and treatment of sepsis lethality by the induction of tolerance to the lethal effects of TNF. The more promising cytokine appears to be rIL-1 because it has less toxicity and more rapid induction of full therapeutic effectiveness.

Animals↗
PubMed1990

Prolonged survival of tumor-bearing rats with repetitive low-dose recombinant tumor necrosis factor.

Tumor necrosis factor may be a mediator of the syndrome of cancer cachexia. Tachyphylaxis or tolerance to the cachectic effects of recombinant tumor necrosis factor (rTNF) has been previously described. In this study, we investigate whether repetitive exposure to rTNF can induce similar tolerance in tumor-bearing (TB) rats and ameliorate cachexia induced by the tumor. In experiment 1, non-tumor-bearing (NTB) and TB rats were randomized to either escalating low doses of rTNF or saline i.p. twice daily for 9 consecutive days. NTB rats treated with rTNF demonstrated a significant decline in food intake and weight change (P less than 0.00001) but soon developed tolerance to the cachectic effects of rTNF; they consumed significantly more food than on the first day of treatment and had weight change similar to NTB rats treated with saline. TB rats treated with rTNF showed a similar significant decline in food intake and weight change (P less than 0.0001) and also demonstrated similar tolerance to the cachectic effects of rTNF with continued treatment. Following treatment, TB rats that had been treated with rTNF ate significantly more and lost less weight than TB rats that had been treated with saline (P less than 0.00001). rTNF treatment of TB rats also demonstrated antineoplastic activity, as estimated tumor weight of tumors from rats treated with rTNF were significantly less than controls (P = 0.003). The anticachexia and antineoplastic effects of rTNF resulted in prolonged survival of TB rats treated with rTNF compared to control TB rats (P = 0.015). Experiment 2 utilized two different rTNF treatment regimens in TB rats: one group received 12 days of escalating doses of rTNF, and another group received 15 days of rTNF treatment. TB rats treated with rTNF again had a significantly greater food intake (P less than 0.00001) and delayed weight loss (P = 0.0001) posttreatment that was further augmented by additional doses of rTNF. Antineoplastic activity of rTNF was less clear, and overall tumor growth curves were not affected by rTNF treatment. Survival of TB rats treated with rTNF was again significantly increased in a dose-dependent manner (P = 0.006). Repeated administration of low doses of rTNF to TB rats induces mild reduction in tumor growth, tolerance to the cachectic effects of rTNF that results in tolerance to the cachectic effects of tumor, and prolongation of survival.

Animals↗
PubMed1990

Impact of tolerance on antitumor efficacy of tumor necrosis factor in mice.

Repetitive sublethal doses of tumor necrosis factor (TNF) can induce tolerance or tachyphylaxis to the toxic effects of TNF. Because tumor-bearing (TB) mice are more sensitive to the toxic effects of TNF, this study investigates whether similar tolerance occurs in TB mice and whether it affects the antitumor response of TNF. Nontumor-bearing C3H/Hen mice were treated with twice daily i.p. sublethal escalating doses of human recombinant TNF (2, 2, 3, 3, 4, and 4 micrograms i.p. every 12 h for 6 days) and were challenged 2 days later with a lethal i.v. dose (40 micrograms) of TNF. TNF-pretreated mice had 100% survival as compared to 0% survival in control mice previously treated with saline (P less than 0.01). Tumor-bearing C57BL/6 mice bearing an MCA-106 or MCA-102 sarcoma were treated with an identical TNF-tolerizing regimen (2, 2, 3, 3, 4, and 4 micrograms i.p. every 12 h for 6 days) beginning 3 days following tumor inoculation and were similarly more resistant to a subsequent 100% lethal i.v. treatment dose of TNF than control TB mice. A significantly greater percentage of TNF-pretreated mice bearing the MCA-106 sarcoma survived treatment doses of 8, 12, and 16 micrograms of TNF i.v. than control TB mice. Similarly, a significantly greater percentage of TNF-pretreated mice bearing the MCA-102 sarcoma survived treatment doses of 6 and 9 micrograms of TNF i.v. than control TB mice. However, the ability to administer higher doses of TNF i.v. to TNF-pretreated TB mice did not improve therapeutic efficacy. In mice bearing the MCA-106 tumor the most efficacious treatment responses were seen in animals that were previously naive to TNF, and treatment toxicity (lethality) correlated directly with antitumor efficacy such that larger treatment doses of TNF in tolerant mice resulted in similar antitumor effects as smaller treatment doses in control TB mice. In mice bearing the MCA-102 tumor, equitoxic treatment doses of TNF produced similar antitumor effects in both control and tolerant TB mice. There were no differences in cure rate for TNF-tolerant or control TB mice bearing either tumor. The results suggest that TNF tolerance occurs in TB mice and reduces the toxicity as well as the therapeutic efficacy of TNF.

Animals↗
PubMed1990

Malignant melanoma metastatic to the thyroid as initial evidence of disseminated disease.

A 48-year-old Caucasian male with a 3 mm sub-ungual right middle finger melanoma underwent cisplatin forequarter perfusion, ray amputation, and ipsilateral axillary node dissection. Two months post-operatively he presented with a thyroid mass as initial evidence of disseminated disease. Subsequent workup also demonstrated pulmonary metastases. A total thyroidectomy radical neck dissection and multi-agent chemotherapy has controlled the disease in his neck. As far as we are aware, this is the first case report of malignant melanoma metastatic to the thyroid. The potentially beneficial role of surgery in the management of metastatic melanoma and the relation of melanoma to the hormonal axis is discussed.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1989

Management of islet cell tumors in patients with multiple endocrine neoplasia: a prospective study.

As part of a study to manage islet cell tumors in patients with multiple endocrine neoplasia (MEN), patients with MEN I and Zollinger-Ellison syndrome (ZES) underwent surgery if a pancreatic islet cell tumor was identified on imaging studies. Patients with MEN I and either insulinoma or vasoactive intestinal polypeptide tumor (VIPoma) underwent surgery whether or not a tumor was identified. Each patient underwent preoperative portal venous sampling (PVS). Nine patients with MEN I and one with MEN II underwent surgery; seven had ZES, one had insulinoma, one had VIPoma, and one had both insulinoma and ZES. Eight of the nine patients with MEN I had an identifiable hormone gradient on PVS. Islet cell tumors were removed from the pancreas of each patient; two patients also had duodenal wall tumors, and three patients had malignant islet cell tumors. No patient with ZES and MEN I was cured of ZES despite the fact that islet cell tumor was removed from the region of the gastrin gradient in five of six patients. The single patient with MEN II and ZES and the three additional patients with MEN I and either insulinoma or VIPoma were cured by islet cell tumor resection. The results indicate that islet cell tumors in patients with MEN I can be both extrapancreatic and malignant. In patients with MEN I and ZES, ZES cannot be cured by tumor resection, and PVS cannot be used to select patients for curative surgery. It appears that gastrinoma in patients with MEN II, as well as either insulinoma or VIPoma in patients with MEN I, can be cured by islet cell tumor resection.

Adenoma, Islet Cell↗
PubMed1989

Prevention and treatment of endotoxin and sepsis lethality with recombinant human tumor necrosis factor.

Tumor necrosis factor (TNF) is a macrophage product released in response to endotoxin that has been implicated as a cause of the toxicity and lethality seen in septic shock. Previous work suggests that tolerance to nutritional and lethal effects of TNF occur after repeated exposure to recombinant tumor necrosis factor (rTNF). In this study pretreatment of rats with a single low intravenous dose of rTNF prevented subsequent death when a lethal dose of rTNF was administered 24 hours later (tolerance or tachyphylaxis). Pretreatment with rTNF also afforded protection against the lethal effects of either endotoxin or cecal ligation and puncture when rats were challenged 24 hours later. Recombinant TNF injected 6 hours after cecal ligation and puncture initially resulted in a significant survival advantage for treated animals. When this experiment was repeated with a different lot of rTNF, however, the therapeutic benefit of rTNF was not obtained until the dose was decreased by a factor of 10. Protection against the lethal effects of cecal ligation and puncture did not occur when rTNF was given 24 hours after the insult. A single low dose of rTNF can result in tolerance or tachyphylaxis to the lethal effects of TNF. The results suggest that the early administration of low-dose rTNF may be useful in the prevention and treatment of the lethality of sepsis.

Animals↗
PubMed1985

Effect of dopamine and dopamine-receptor blockade on in vitro renin release, tissue renin content and tissue cyclic AMP content in the rat.

This study evaluated the in vitro renin release, tissue cyclic AMP content (TcAMPc), and tissue renin content (TRC) changes with time, in response to administration of dopamine (DOP) and of the dopamine-receptor blocking agent pimozide (PIM) to renal cortical slices from sodium deficient (SD) rats. Addition of 10(-3)M DOP to the slice preparation resulted in a gradual stimulation of RR with time, which was significantly different from that seen in control samples after 60 min of incubation. In contrast, TcAMPc of the DOP-treated samples was significantly greater than that of controls after 5 min of incubation. At 60 min, mean TRC of DOP-treated samples was greater than that of controls but not significantly. Two PIM doses (10(-8)M and 10(-6)M, whether added alone or together with 10(-3)M DOP to the cortical slice system, significantly increased RR in each instance while simultaneously depressing TcAMP content markedly below that of unstimulated controls at all incubation times examined. Mean TRC of pimozide-treated samples was also lower than that of controls by 60 min. These in vitro data in the SD rat suggest that: 1) stimulation of renin release by DOP is time-dependent and is mediated by a TcAMP-generating mechanism, and 2) the increase in renin release by PIM administration appears to involve pharmacological inactivation of TcAMP-generating pathways and disruption of membrane permeability, leading to uncontrolled RR.

Animals↗
PubMedDate not supplied

Long-term outcome of completion gastrectomy for nonmalignant disease.

Between 1989 and 1995 we performed completion gastrectomy for non-malignant disease in 21 patients (11 men and 10 women, mean age 48.4 years). These patients had undergone a total of 48 prior gastric operations. Indications for completion gastrectomy in this group were anastomotic ulceration with stricture in eight patients, alkaline reflux gastritis and/or esophagitis in eight, postsurgical gastroparesis in two, gastroesophageal necrosis in two, and gastrocutaneous fistula in one. Major preoperative symptoms included nausea and vomiting in 16 cases, abdominal pain in 15, dysphagia in 14, heartburn in seven, and weight loss in five. Following completion gastrectomy, five patients (24%) had serious complications and there was one postoperative death (5%). Five patients were lost to follow-up. For the remaining 15 patients, mean follow-up has been 30 months with a range of 1 to 70 months. These patients were all interviewed and eight (53%) report significant improvement, two (13%) report moderate improvement, and four (27%) report no improvement; one patient (7%) has had worsening of symptoms since undergoing completion gastrectomy. The average body weight index was essentially unchanged after completion gastrectomy. We conclude that completion gastrectomy with Roux-en-Y esophagojejunostomy results in a favorable outcome in the majority of selected patients with diseases of the foregut who are unresponsive to less radical treatment.

Female↗