Enrique Gonzalez

Association between Cell Membrane Potential and Breast Cancer

Cell membrane potentials were measured in breast tissue and in breast epithelial cells to explore the relation between cell membrane potentials, oncogenesis and electrical potentials previously measured on the surface of the breast. The mean membrane potential in breast biopsy tissue from 9 women with infiltrating ductal carcinoma was significantly depolarized, compared with values measured in tissue from 8 women with benign breast disease. Depolarization was also observed in transformed breast epithelial cells, compared with normal breast cells; the transformed cells were particularly sensitive to the action of K+ channel blockers. The results were consistent with previous observations of electropositivity of skin sites over malignant tumors of the breast.

An animal model of necrotizing enterocolitis induced by infant formula and ischemia in developing piglets

BACKGROUND/AIMS The lipid component of piglet formula (0.5% fat) causes increased mucosal permeability in 1-day-old piglets after ischemia/reperfusion. The present study examined if luminal exposure to infant formulas (3.5% fat) and ischemia/reperfusion result in an animal model of necrotizing enterocolitis and if injury is dependent on the formula fat composition. METHODS Plasma-to-lumen clearance of 51Cr-ethylenediamine-tetraacetic acid was measured, and morphology was evaluated during luminal perfusion with preterm, term, and delipidated preterm cow milk-based infant formulas before and after ischemia/reperfusion in 1-day-old and 1-month-old piglet jejunoileum. In a separate set of experiments, a 1-2-cm segment of ileum was exteriorized and opened to expose the mucosal surface, and the villi were superfused with the above formulas (no ischemia). RESULTS Before ischemia, clearances were markedly higher for intestinal loops perfused with preterm formula than for loops perfused with term and delipidated formulas in 1-day-old animals. After ischemia, clearances in loops perfused with preterm formula were significantly greater and grossly hemorrhagic and histologically necrotic compared with loops perfused with delipidated formula (minimal injury). Superfusion with preterm formula caused diffuse hyperemia and hemorrhage into intestinal villi. CONCLUSIONS Luminal perfusion of 1-day-old piglet jejunoileum with predigested and bile acid-solubilized preterm infant formula, in combination with ischemia/reperfusion, produces an animal model of necrotizing enterocolitis, but only if the lipid fraction of the formula is present.

Testicular microlithiasis as a predictor of intratubular germ cell neoplasia

Sonographically detected testicular microlithiasis is an uncommon condition, which in recent years has been demonstrated with increased prevalence in patients with testicular tumors. We report a case of a 31-year-old man with left testicular carcinoma and right intratubular germ cell neoplasia diagnosed by biopsy of the right testis at the time of left radical orchiectomy. In this case, preoperative ultrasound revealed right testicular microlithiasis, signaling the presence of intratubular germ cell neoplasia. We propose ultrasound as a noninvasive tool for selecting patients for testicular biopsy.

Granulocyte turnover in the feline intestine

The objective of this study was to determine the turnover rate of the extravascular pool of granulocytes in different regions of the feline gastrointestinal tract. Leukocyte emigration from the vasculature was prevented over a 48-h period by repeated intravenous injections of a monoclonal antibody (MAb IB4) directed against the leukocyte adhesion glycoprotein complex CD11/CD18. Tissue-associated myeloperoxidase (MPO) activity was used to monitor the total tissue granulocyte pool at 0.5, 12, 24, and 48 h after MAb IB4 administration. The mucosal layer of the duodenum, jejunum, ileum, and colon exhibited different kinetics of granulocyte clearance, with average life-spans (t1/2) ranging between 6.9 (colon) and 10.4 h (duodenum). Granulocyte clearance rates of 0.5 × 106 and 2.4 x 106 cells/h/g tissue were estimated (from measured values oft1/2 and tissue granulocyte pool) for the small bowel and colonie mucosae, respectively. The submucosal layer of the intestine exhibited a biphasic reduction in tissue MPO activity following immunoneutralization of CD11/CD18, with an initialt1/2 ≤ 0.5 h followed by at1/2 of 36–60 h. The initial rapid decline in tissue MPO suggests that a significant fraction of granulocytes in the submucosa is localized in a readily exchangeable pool (e.g., marginated cells within the vasculature). The results of this study indicate that the average life-span of resident granulocytes varies significantly between different regions of the gastrointestinal tract, with the intestinal mucosa exhibiting at1/2 comparable to that previously reported for circulating feline neutrophils (R 8 h).

Pancreatic Transplantation and Subsequent Graft Surveillance by Pancreatic Portal–Enteric Anastomosis and Temporary Venting Jejunostomy

ObjectiveTo evaluate portal–enteric (PE) pancreas and kidney transplantation with venting jejunostomy (VJ) for its efficacy, safety, and reproducibility. Summary Background DataSimultaneous pancreas and kidney transplantation for patients with long-standing insulin-dependent diabetes mellitus that progresses to renal failure has revolutionized their treatment and quality of life. A current clinical focus is to refine the technical aspects of this procedure. Simultaneous pancreas and kidney transplantation with PE anastomosis with VJ appears to offer several advantages over bladder drainage. VJ allows initial decompression of the enteric anastomosis, monitoring of pancreatic function by ostomy amylase, and simple access for endoscopic evaluation and biopsy of the allograft. MethodsSimultaneous pancreas and kidney transplantation with VJ was performed in 21 patients from December 1996 to October 2000 at Willis Knighton/LSU Regional Transplant Center. All patients had long-standing insulin-dependent diabetes mellitus and subsequent renal failure. They were evaluated at the time of surgery by a multidisciplinary transplant team and monitored for numerous factors, including length of hospital stay, immunosuppressive regimen, and ischemia times. All patients had intermittent visual and biochemical evaluation of pancreatic secretions monitored by means of the VJ. ResultsOf the 21 patients, 10 were women and 11 were men. Four patients were black and 17 were white. The mean age at transplantation was 38 years; average human leukocyte antigen (HLA) match was one; and average cold ischemia time was 12 hours. The median hospital stay was 16 days. Four episodes of postoperative bleeding requiring exploration occurred in four patients. Postoperative wound infections developed in four patients. There were 12 episodes of rejection in nine patients. All patients with suspected acute pancreatic rejection underwent endoscopy by means of the VJ and duodenal biopsy for evaluation. Two patients lost pancreatic function subsequent to kidney failure, one secondary to noncompliance and the other as a result of hemolytic-uremic syndrome. Patient, kidney, and pancreatic survival rates were 100%, 90%, and 90%, respectively. The mean follow-up period was 25 (range 2–48) months. ConclusionThe authors believe that PE pancreatic drainage with VJ is a more physiologic method to perform pancreatic transplantation than bladder drainage. PE drainage allows rapid diagnosis of acute rejection and anastomotic leak and provides a simple way to monitor ostomy amylase and transplant duodenal bleeding. This technique is safe and has minimal associated complications.

Roux-en-y venting jejunostomy in pancreatic transplantation: a novel approach to monitor rejection and prevent anastomotic leak

Introduction: Pancreatic transplantation (PTx) with portal venous delivery of insulin and enteric drainage of the exocrine secretion is more physiologic than bladder‐systemic (BS) drainage. With portal‐enteric (PE) PTx, the diagnosis of acute rejection (AR) requires a percutaneous biopsy. The roux‐en‐y (RNY) venting jejunostomy in patients with PEPTx offers a novel approach to monitor rejection and prevent anastomatic leaks. 
Methods. From January 1996 to December 1998, we performed 17 simultaneous kidney/pancreas transplants (SKPTx). The initial 4 patients underwent BS drainage and the subsequent 13 patients underwent RNY venting jejunostomy with PE drainage. All patients were treated with quadruple therapy. There were 9 males, 14 patients were Caucasian with a mean age of 32 yr (range 30–54 yr), and a mean pre‐transplantation duration of diabetes of 25 yr. Six patients underwent endoscopic donor duodenal biopsy through the jejunostomy to rule out clinically suspected AR. Gastrograffin was inserted into the jejunostomy to examine the integrity of anastamosis when indicated. In 9 out of 13 patients, the venting jejunostomy was taken down 9–12 months post‐transplantation after allograft function was stable. 
Results. Actual patient, kidney, and pancreas graft survival rates were 100, 100 and 94%, respectively, after a mean follow‐up of 16 months. Renal allografts functioned immediately in 89% of patients. The mean length of hospital stay was 19 d. Four (23%) patients (2 with BS drainage and 2 with PE drainage) suffered an AR episode in the first month, and 4 (23%) patients had five AR from 3–36 months post‐transplantation. Other complications were post‐operative bleeding in 3 patients, wound infection in 2 patients and a proximal duodenal stump leak in 1 patient. In patients with clinical rejection, endoscopy through the venting jejunostomy showed inflamed, friable doudenal mucosa and doudenal biopsy findings were compatible with AR. 
Conclusion. These preliminary results suggest that RNY venting jejunostomy with PE drainage can be used safely to diagnose and monitor pancreas AR and to diagnose and prevent anastamotic leaks. This technique will be even more useful to visualize transplanted duodenal mucosa, collect pancreatic secretions (amylase) for analysis and perform endoscopic retrograde cholangiopancreatography if needed to obtain pancreatic biopsies.

Pyoderma Gangrenosum of Penile and Scrotal Skin

AbstractPyoderma gangrenosum is a unique cutaneous ulceration with characteristic clinical features. Although pyoderma gangrenosum may occur on any area of the body it is most commonly found on the lower extremities. Involvement of the external genitalia is rare. We report a case of pyoderma gangrenosum involving the penile and scrotal skin associated with ulcerative colitis. The cutaneous genital lesions were the major presenting manifestations of an underlying chronic inflammatory bowel disease.

Electrochemical modification of tumor growth in mice

We evaluated the effect of direct electrical current on large tumors in mice. Lewis lung carcinoma greater than 1 cm in the shortest dimension was treated percutaneously with 20 mA for 15 min. Separate groups were given one or more than one (two or three) percutaneous electrical treatments (PET). A third group was given sham electrical treatment, and a fourth group had surgical excision of the tumor. Animals in both PET groups survived longer and had smaller primary tumors at death compared with the sham group. PET did not alter the systemic course of the disease, judged by lung and spleen weights and by histological observation of the extent of metastatic burden in the lung. Surgery resulted in long-term survival of 17% and an increase in average survival time compared with both PET and sham treatment. PET produced rapid and polarity-dependent alterations in physiological solutions in vitro, and it is likely that similar electrochemical processes mediated the observed reduction in tumor growth. PET is potentially useful as an adjuvant modality because it reduces local tumor mass but does not alter the extent of metastasis.

Quasi-static charge interactions in bone

Abstract Bones respond to mechanical forces by modifying their architecture. Mechanical forces also result in at least two electromechanical signals in bone — streaming potentials and piezoelectric polarization. Observations of bones parallel architectural and electrical responses to forces have led to suggestions that one or both of the signals mediate the osteogenic response by directly triggering bone-cell activity. This study was undertaken to determine whether piezoelectric polarization could alter bone-cell physiological function. Piezoelectric and non-piezoelectric forms of the polymer polyvinylidene fluoride were implanted in rats, and the effect on periosteum and bone was studied histologically. More bone formation and periosteal reaction occured in association with the piezoelectric form of polyvinylidene fluoride. The effects were statistically significant at 1–6 and 1–2 weeks postoperatively for bone and periosteum, respectively. Nether mechanical nor chemical factors could account for the results, which therefore must have been due to the quasi-static piezoelectric polarization (about 90 pC/cm2). The osteoprogenitor cell but not the mesenchymal cell (its less differentiated precursor) was capable of responding to the polarization.

Primary Signet Ring Cell Adenocarcinoma of the Bladder (Linitis Plastica of the Bladder): Report of a Case and Review of the Literature

Signet ring cell adenocarcinoma of the bladder is a rare tumor that usually presents as a diffuse and infiltrating neoplasm, similar to the linitis plastica type of gastric adenocarcinoma. We report the thirteenth case of primary signet ring cell adenocarcinoma of the bladder, which is documented by light microscopic, immunohistochemical and electron microscopic studies. the pertinent medical literature is reviewed and analyzed. In general, this tumor present with hematuria and irritative symptoms, and may yield equivocal radiologic and cystoscopic findings. It is characterized by a rather rapid growth rate, infiltration of the surrounding pelvic organs, and variable response to radiotherapy and radical surgery. The prognosis is apparently favorably modified by early detection of localized forms of the tumor and aggressive treatment.