Histamine H2-receptor antagonists stimulate proliferation but not migration of human gastric mucosal cellsin vitro

Gastric mucosal cell migration and proliferation are crucial events in the repair of gastric mucosal erosions. This study was designed to test the hypothesis that the H₂ blockers roxatidine and ranitidine might stimulate migration and proliferation of gastric mucous cells derived from a human well-differentiated gastric adenocarcinoma cell line (MKN 28 cells)in vitro, in conditions independent of systemic factors and of acid inhibition. Confluent monolayers of MKN 28 cells were wounded with a razor blade and were then incubated with roxatidine or ranitidine. The number of cells migrating to the damaged area was determined 24 hr later. Cell proliferation was assessed by means of [³H]thymidine uptake and cell counts after incubation with roxatidine or ranitidine. Neither H₂ antagonist significantly stimulated cell migration. On the other hand, cell proliferation was dose-dependently and significantly enhanced by incubation with roxatidine and ranitidine. Exogenous administration of TGF- significantly stimulated MKN 28 cell division. However, incubation with roxatidine or ranitidine did not increase the steady-state mRNA expression of TGF- or EGFR as assessed by northern blot analysis. Based on thesein vitro findings, we postulate that the ulcer healing effect of these H₂ antagonistsin vivo might be due in part to stimulation of gastric mucosal cell proliferation.Data from this paper have been presented in part at the 1995 meeting of the American Gastroenterological Association and published in abstract form in Gastroenterology 108:A72, 1995.     

Effects of long-term treatment with trandolapril on augmented vasoconstriction in rats with chronic heart failure

Background:

Despite the clinical relevance of angiotensin I-converting enzyme (ACE)inhibitors, their effects on impaired vascular function in patients and animals with chronic heart failure (CHF) have not been fully understood. This study was undertaken to determine whether long-term treatment with an ACE inhibitor improved the altered contractile properties of vessels from rats with CHF.

Methods and Results:

Twelve weeks after coronary artery ligation, the rats were sacrificed and the isometric tension development of thoracic aorta, pulmonary artery, and mesenteric artery with and without endothelium was examined. Contractile responses to norepinephrine and prostaglandin F₂α were augmented in endothelium-intact, but not in endothelium-denuded, thoracic aorta and pulmonary artery segments of the rat with CHF. The contractile response to angiotensin II was augmented in endothelium-denuded mesenteric artery segments of the rat with CHF, which was attenuated by indomethacin or diclofenac sodium but not by bunazosin. Trandolapril (3 mg/kg/d) was administered orally from the 2nd to 12th week after the operation. Treatment with trandolapril reversed the augmented contractile response of the rat with CHF to norepinephrine, prostaglandin F₂α, and angiotensin II almost to the levels in the sham-operated rat.

Conclusions:

The results demonstrate that an ACE inhibitor is capable of reversing altered vascular function in the rat with CHF, suggesting that vascular beds are possible sites of action for ACE inhibitors in the therapy for CHF.     

Clinical Measurement of Testicular Volume in Adolescents: Comparison of the Reliability of 5 Methods

Purpose

Measurement of the testis is a more readily available method of estimating spermatogenesis. Doubt remains about the best instrument for measuring testicular volume. Lack of bias or accuracy of instruments has received too much emphasis in some studies, while to our knowledge no one has yet appropriately compared reliability statistically. We propose a simple new method for measuring testicular size based on visual comparison with graphic models, and describe the reliability and bias of this and 4 traditional methods.

Materials and Methods

Measurements of 42 adolescent testes were made in a certain sequence: graphic method, dimensional measurement, Prader orchidometer, ring orchidometer and ultrasound with ultrasound assumed to be the standard. Statistical analysis was based on the linear structural model.

Results

Statistical tests indicated that all 5 methods are equally reliable (R greater than 0.9). Although they are not equally accurate, actual testicular size can be calculated using each of these 5 methods and the equations of the linear structural model.

Conclusions

The new graphic method proposed in this study is as reliable as other well-known methods for measuring testicular size. Actual testicular volume can be estimated without bias and with equal reliability from any of the 5 methods using the equations of the linear structural model. This statistical approach is more relevant than the sole comparison of lack of bias or accuracy, which has been the main concern of previous studies.     

Catecholamines modulate growth and differentiation of human preosteoclastic cells

Using a clonal cell line of human osteoclast precursors (FLG 29.1 cells), that after treatment with 12-O-tetradecanoyl phorbol 13-acetate (TPA) show many functional characteristics of osteoclasts, we demonstrated that catecholamines act as inducers of osteoclast maturation in vitro and as stimulators of osteoclast activity via the binding to ₂ adrenergic receptors. Scatchard analysis of¹²⁵I-labelled iodocyano-pindolol to untreated (undifferentiated) or TPA-treated (differentiated) FLG 29.1 cells revealed the presence of a single high-affinity site with aK _d value around 24 pM and 8 pM respectively and with superimposable binding capacity (1.18 fmol/mg protein). Catecholamines increased in a dose-dependent fashion the intracellular cyclic AMP (cAMP) accumulation in both undifferentiated and TPA-treated FLG 29.1 cells. Pretreatment of untreated and TPA-treated FLG 29.1 cells with propranolol inhibited the catecholamine effect on cAMP accumulation, while pretreatment with clonidine had no effect. Catecholamines also reduced cell proliferation, increased tartrate-resistant acid phosphatase (TRAcP) activity, interleukin 6 (IL-6) production, multinuclearity and response to salmon calcitonin (sCT) in undifferentiated FLG 29.1 cells. In differentiated FLG 29.1 cells only IL-6 release was induced by catecholamine treatment. These findings support a potential role for catecholamines in modulating osteoclast differentiation and mature osteoclast activity.     

Pay Status as a Predictor of Outcome in Surgical Treatment of Obesity

Background: Higher complication rates and lower success in surgery for severe obesity have been reported for patients with government pay status. We examined the effect of pay status upon outcome in surgical treatment of obesity. Methods: This was an observational study from an aggregate data set of individual patient information. Government pay status (G) was defined as full or partial medical care payment through Medicare, Medicaid, or Veterans Administration. Payment entirely by private insurance was defined as private (P). Operations were classified as either simple (S, gastric restriction) or complex (C, gastric restriction with small bowel bypass). Two measures of outcome, perioperative complication rate and weight loss success (≤50% excess weight), were examined to determine pay status effect. Results: More G than P patients were treated with simple procedures (79% vs 51%, p < 0.05). Perioperative complication rates were more common for G than P patients (14.4% vs 9.1%, p < 0.05). One-year weight loss success was higher for P than G, regardless of operation type. Conclusion: Pay status should be included in characterization of patient groups and in the analysis of results when effectiveness of surgical treatment for severe obesity is reported.     

Comparative Pharmacology of Cisatracurium (51W89), Atracurium, and Five Isomers in Cats

Background: Atracurium has four chiral centers and the marketed product is a mixture of ten optical and geometric isomers. Six of the isomers were prepared and evaluated for neuromuscular blocking activity and autonomic effects in anesthetized cats. This study reports the comparative pharmacology of the six isomers and atracurium that led to the selection of one isomer, cisatracurium (Nimbex, 51W89) for clinical development.

Methods: Purpose bred cats, anesthetized with alpha-chloralose (80 mg/kg) and pentobarbital sodium (7 mg/kg) administered intraperitoneally, were used in this study. Neuromuscular blocking effects were assessed from the effects on the tibialis anterior twitch evoked at 0.15 Hz. Inhibition of the autonomic nervous system was assessed from the effects on the nictitating membrane contraction, in response to preganglionic sympathetic nerve stimulation and the bradycardia/vasodepressor responses to vagal nerve stimulation. Cardiovascular effects and plasma histamine concentrations were determined after a bolus injection of cisatracurium or atracurium.

Results: Like atracurium, all six isomers produced dose-dependent neuromuscular block (NMB). The calculated ED95 NMB values varied approximately tenfold (43+/-2 micro gram/kg-488+/-56 micro gram/kg). The "R-series" isomers were more potent than the corresponding "S series" isomers. With the exception of the S,Trans-S', Trans isomer, the NMB effects, i.e., onset times (range 2.6+/-0.2 min to 4.7+/-0.3 min) and total durations (range 9.9+/- 1.4 min to 14+/-0.9 min), of the other five isomers were very similar to that of atracurium. The former isomer had a relatively short duration of action. The 25-75% recovery times after cisatracurium at 1x ED sub 95 (4.4+/-0.4 min), 4x ED95 (4.5+/-0.4 min), and continuous infusions lasting at least 60 min that maintained 95-99% NMB (4.8+/-0.4 min) indicated a noncumulative effect. The vagal ID50: NMB ED95 ratios for atracurium and the six isomers ranged from 2 to 27. The sympathetic ID25: NMB ED95 ranged from 2.7 to 60. Atracurium and all of the isomers, except cisatracurium, produced cardiovascular effects after intravenous bolus administration at large doses (700-4,800 micro gram/kg). In contrast to atracurium, there were no changes in plasma histamine concentrations associated with the administration of doses of cisatracurium equivalent to 60x the NMB ED95 (62+/-8 micro gram/kg).     

Back to the future for wound care?

The European Renaissance was a time of enormous change and rapid progress in the arts, sciences, and medicine. A glimpse of wound care in the last phase of the European Renaissance is provided by the analysis of work by Wilhelm Fabry, the "father of German surgery," as provided in his book De Combustionibus ("Burns") which details his range of treatments for the burn wound, as well as his approach to the later problems of scarring and contracture. We describe some of the historic events which may have stimulated Fabry's writings, in particular, the influences passed down from the medical school of Padua which thereby advanced the cause of wound care and surgery. Finally, we briefly explore the potential of such an approach to the works of our medical forefathers.     

Molecular diagnosis of exocrine pancreatic cancer using a percutaneous technique

Background: The K-ras oncogene is activated by point mutations at codon 12 in most patients with exocrine pancreatic cancer. Mutant-enriched polymerase chain reaction (PCR) amplification can enhance the detection of mutated K-ras. This technique was applied to patients undergoing percutaneous fine-needle aspiration (FNA) biopsy of suspect pancreatic lesions. Methods: Twenty-five patients underwent percutaneous FNA of the pancreas for cytologic and molecular analysis. After preparing cytologic smears, the 22-gauge needle and syringe used for FNA were rinsed in RPMI-1640. The specimen was centrifuged, and DNA was extracted from the supernatant and subjected to mutant-enriched PCR using appropriate mismatched primers that introduce a BstNI restriction endonuclease cleavage site at codon 12 of wild-type, but not mutant, K-ras. After digestion with BstNI, the DNA was reamplified. To increase assay sensitivity, the final five PCR cycles were completed incorporating 5 μCi of (α-32P)dCTP. The DNA was then redigested and subjected to gel electrophoresis and autoradiography. Results: The median amount of DNA retrieved per specimen was 3.33 μg. Mutant K-ras was detected as a band of 143 bps; residual wild-type DNA was seen as a 114-bp fragment. Twenty-one of 25 specimens demonstrated mutated K-ras DNA. Two patients with nondiagnostic cytology results had mutated K-ras DNA; adenocarcinoma of pancreatic origin was confirmed in both cases after pancreatectomy. Conclusion: The molecular diagnosis of pancreatic cancer through identification of mutations in K-ras can be readily performed on specimens obtained by percutaneous FNA. As aggressive multimodality management of this disease becomes more common, pretreatment analysis of molecular determinants may have greater clinical significance. Presented at the 48th Cancer Symposium of The Society of Surgical Oncology, Boston, Massachusetts, March 23–26, 1995.     

Role of endogenous interferon gamma in murine tumor growth and tumor necrosis factor alpha antitumor efficacy

Background: The anticancer role of tumor necrosis factor-alpha (TNF-) has been limited by toxicity. These experiments evaluate blocking endogenous interferon-gamma (IFN-) activity to abrogate TNF- toxicity. Methods: C57Bl/6 mice bearing MCA 105 tumor were treated with TNF- and anti-IFN- antibody (Ab) to evaluate the effect on the acute lethality of TNF- and their efficacy as evaluated by tumor growth rate, tumor histology, and survival. Results: Anti-IFN- Ab decreased TNF- lethality. Anti-IFN- Ab alone increased tumor growth significantly more than did nonimmune IgG (p₂<0.0001). Tumor-bearing mice that received nonimmune IgG and TNF- had slower tumor growth (p₂<0.02) and a trend toward improved survival (p=0.07) compared with saline-treated controls. Anti-IFN- Ab abrogated the antitumor effect of TNF-, prevented acute tumor necrosis histologically, and resulted in tumor growth rate and host survival similar to that of controls. The findings in mice that received anti-IFN- Ab and high-dose TNF- were comparable with those in mice that received a lower, equitoxic dose of TNF- alone. Conclusions: Blocking endogenous IFN- accelerates tumor growth in this model and partially abrogates the toxic and antitumor activity of exogenous TNF- equally. This suggests that blocking endogenous IFN- activity is not a useful strategy for limiting TNF- treatment toxicity.Presented in part at the 45th Annual Cancer Symposium of The Society of Surgical Oncology, New York, New York, March 15–18, 1992.