Characterization of a novel model of pancreatic fibrosis and acinar atrophy

Significant fibrosis and acinar atrophy are characteristics of chronic pancreatitis; however, because of the lack of a reproducible model, early phases of these changes are poorly understood. We have developed a model of severe hyperstimulation and obstruction pancreatitis (SHOP) to better define the mechanisms of early pancreatic fibrogenesis. Sprague-Dawley rats were used and SHOP was induced by complete pancreatic duct obstruction and daily cerulein hyperstimulation (50 microg/kg intraperitoneally). Animals were killed at 24, 48, 72, and 96 hours. Control animals underwent sham operation and received no cerulein. Pancreata were prepared for hematoxylin and eosin and sirius red (collagen-specific) staining and for hydroxyproline assay (measure of total collagen content). We found moderate amounts of edema and inflammation but minimal parenchymal necrosis. Significant loss of acinar cell mass was noted by 48 hours, and normal acinar cells were essentially absent by 96 hours. Tissue collagen content increased with time and large amounts of interstitial collagen were detected by 72 hours. In conclusion, SHOP is a novel model of early pancreatic fibrosis associated with minimal necrosis and a significant decrease in acinar cell mass, making it an ideal model to study the early cellular mechanisms of pancreatic fibrogenesis.

Dry soda lime markedly degrades sevoflurane during simulated inhalation induction

We have investigated gas composition during simulated inhalation induction with sevoflurane to elucidate possible mechanisms of incidental prolonged induction times and airway irritation. Using a circle system, 8% sevoflurane in oxygen 6 litre min-1 was washed into an absorbing canister filled with fresh soda lime containing 2.9% KOH (Draegersorb, 'D') or no KOH (< 0.01%, Sofnolime, 'S'). The absorbent was dried by oxygen 20,000 litre before every second experiment. Maximum soda lime temperatures attained after 4-6 min were 107 degrees C using dry D and 62 degrees C (61 degrees C) with dry S. Temperature did not increase with fresh soda lime. With dry soda lime, sevoflurane was not detected at the T-piece for 3 min and reached 6-7% within 6-10 min. After 1 min, we detected methanol and compound A (CH2F-O-C(= CF2) (CF3)). Total amounts over 20 min were: methanol 1125 mg (D dry), 334 mg (S dry) and < 5 mg (fresh soda lime); compound A 148 mg (D dry), 13 mg (S dry) and 3-8 mg (fresh); and fluoride 8.5 mg (D dry), 3.3 mg (S dry) and 1 mg (fresh). Formaldehyde was detected only with dry lime (D > 2.5 mg, S > 0.6 mg). In summary, the use of moist soda lime is of crucial importance during inhalation induction. With dry soda lime, the patient may inhale potentially toxic degradation products in significant amounts. Sevoflurane degradation is aggravated by a high KOH content of the lime. The observed airway irritation may be caused by formic acid, which is generated in isomolar concentrations with methanol (Cannizzaro reaction). The amount of compound A found with dry KOH-containing lime is unlikely to be noxious.

Sister chromatid exchange in human lymphocytes exposed to isoflurane and nitrous oxide in vitro

The question of whether or not inhalation anaesthetics are genotoxic remains controversial. Therefore, we have studied the in vitro genotoxic potential of isoflurane and nitrous oxide in human lymphocytes. Blood samples were obtained from eight healthy male, non-smoking volunteers, which were incubated and exposed to increasing concentrations of isoflurane (0.0, 0.3, 0.6 and 1.2 mmol litre-1) or 50% nitrous oxide in oxygen. Baseline sister chromatid exchange (SCE) rate per cell was mean 7.65 (SD 1.5) which increased to 9.15 (1.0), 9.55 (1.4) and 9.95 (1.8) SCE/cell during exposure to isoflurane 0.3, 0.6 and 1.2 mmol litre-1, respectively. During 50% nitrous oxide exposure, SCE rate was 9.26 (1.4). The difference between the control and exposed cells was statistically significant (P < or = 0.05). We conclude that exposure to nitrous oxide and subanaesthetic concentrations of isoflurane can produce genetic damage in peripheral lymphocytes in vitro.

Protein binding of piritramide: influence of various protein concentrations and the postoperative acute phase response

OBJECTIVE

Piritramide is a lipophilic opioid, which is widely used for postoperative analgesia and analgosedation in Europe. In this study we investigated the influence of various protein concentrations (total protein, alpha1-acid glycoprotein, albumin) and the postoperative acute phase response on the protein binding of piritramide.

METHODS

The influence of various protein concentrations on the protein binding of piritramide was investigated by either diluting the serum samples of five volunteers with isotonic saline or by adding different amounts of alpha1-acid glycoprotein. Albumin binding was measured in a 5% human albumin solution. The impact of the postoperative acute phase response was investigated by obtaining daily serum samples from 18 surgical patients until the third postoperative day, and measuring piritramide protein binding, alpha1-acid glycoprotein, total protein and albumin.

RESULTS

There was a significant relationship between piritramide protein binding and the concentrations of total protein and alpha1-acid glycoprotein. The binding to albumin was 88%. During the postoperative acute phase response, the protein binding of piritramide did not change. Serum concentrations of alpha1-acid glycoprotein increased, whereas total protein and albumin decreased.

CONCLUSION

Although there were significant changes in the piritramide-binding proteins, alpha1-acid glycoprotein and albumin, during the postoperative acute phase response, the protein binding of piritramide did not change. Therefore, a change in protein binding, which might be one factor to be considered in determining piritramide dosage in the postoperative period, does not have to be taken into account.

Colorectal cancer detection and screening

Colon cancer is a leading cause of death in the United States and is estimated to cause 56,500 deaths during 1998. Most cancers evolve from adenomatous polyps. Screening asymptomatic average-risk individuals is recommended to reduce colorectal cancer mortality by detection and removal of adenomatous polyps.

Purging and haemopoietic progenitor cell selection by CD34+ cell separation

Tumour cell contamination of autologous peripheral blood stem cell samples (PBSC) and bone marrow (BM) is frequent. Enrichment of CD34+ stem cells is a promising approach to purging tumour cells from autografts without damaging progenitor cells. Breast cancer cells were seeded (10(-3)-10(-7)) into mononuclear cells from G-CSF-mobilised PBSC and BM harvests from patients without breast cancer. CD34+ cells were enriched from mixtures either by immunomagnetic separation (Isolex-50, and MiniMACS) or by biotin-streptavidin immunoaffinity columns (Ceprate-LC). CD34+ cell fractions were determined by FACS, cancer cells were detected immunocytochemically with an anti-pancytokeratin antibody. The CD34+ cells were enriched with a median purity of 92.2% (43.5-96.1) (n = 17) (Isolex-50), 96.5% (66.6-99.2) (n = 17) (MiniMACS) and 77.9% (31.4-93.6) (n = 15) (Ceprate-LC) from PBSC and BM harvests. The percentages of median recovery of CD34+ cells were 30.8% (18.6-71.8) (Isolex-50), 69.9% (39.1-100) (MiniMACS) and 42.9% (23.7-100) (Ceprate-LC). The median tumour cell reductions in log steps were 3.7 (2.9-4.3) (n = 13) (Isolex-50), 3.5 (2.6-4.3) (n = 13) (MiniMACS) and 1.5 (0.9-2.9) (n = 17) (Ceprate-LC). Results were compared statistically by univariate analysis. Purity was significantly (P < 0.05) better after MiniMACS selection. Recovery rates were significantly different between all devices tested. Tumour cell purging was superior after immunomagnetic separation (P < 0.001). Tumour cell purging is a main objective of CD34+ selection in the autologous setting. Our in vitro data clearly indicate that immunomagnetic separation is more efficient in the prevention of accidental reinfusion of contaminating tumour cells compared to immunoaffinity. However, it is not yet known if the same results can be obtained with fresh contaminating tumour cells.

A polyoma-based episomal vector efficiently expresses exogenous genes in mouse embryonic stem cells

We describe the ability of novel episomally maintained vectors to efficiently promote gene expression in embryonic stem (ES) cells as well as in established mouse cell lines. Extrachromosomal maintenance of our vectors is based on the presence of polyoma virus DNA sequences, including the origin of replication harboring a mutant enhancer (PyF101), and a modified version of the polyoma early region (LT20) encoding the large T antigen only. Reporter gene expression from such extrachromosomally replicating vectors was approximately 10-fold higher than expression from replication-incompetent control plasmids. After transfection of different ES cell lines, the polyoma virus-derived plasmid variant pMGD20neo (7.2 kb) was maintained episomally in 16% of the G418-resistant clones. No chromosomal integration of pMGD20neo vector DNA was detected in ES cells that contained episomal vector DNA even after long term passage. The vector's replication ability was not altered after insertion of up to 10 kb hprt gene fragments. Besides undifferentiated ES cells, the polyoma-based vectors were also maintained extrachromosomally in differentiating ES cells and embryoid bodies as well as in established mouse cell lines.

Detection of cancer cells in peripheral blood stem cells of women with breast cancer by RT-PCR and cell culture

The benefit of high-dose therapy and blood stem cell reinfusion for women with high-risk breast cancer is currently under investigation. Contaminations of autologous blood stem cells with cancer cells have been described. Cancer micrometastases may be detected by immunocytochemistry, culture techniques and cytokeratin-19 mRNA reverse transcriptase PCR. Women with breast cancer received adjuvant HD-CTM with peripheral blood stem cell (PBSC) support after surgical therapy and 4 cycles conventional chemotherapy. Peripheral blood stem cells were mobilised by G-CsF and harvested after the third or fourth cycle of standard therapy. Aliquots of PBSC-collections (10(7)-2*10(7) cells) were subjected to CK19-mRNA reverse transcriptase PCR. RNA was extracted by standard methods and reverse transcription was performed with MMV-RT. Integrity of RNA was checked by coamplification of housekeeping sequences. Aliquots of the RT-mix were subjected to PCR-amplification with outer and inner primer pairs, subsequently. A second aliquot of 2*10(7) cells was cultured over 42 days in liquid culture. Cytospins were prepared weekly from cultured cells and evaluated by light microscopy with or without prior immunocytochemistry. Ten leukaphereses from 6 women were available for PCR-analysis and cell culture. Six leukaphereses were negative for CK19-mRNA and for detection of cancer cells by culture technique, two samples were positive for CK19-mRNA and culturally enriched cells and two samples were positive for CK19-mRNA and negative for cultured cancer cells. No sample was positive for cultured cells and negative for CK19-mRNA. Overall, the results corresponded in 80%. Two sensitive techniques for the detection of cancer micrometastases were applied to aliquots from 10 leukaphereses of six breast cancer patients with corresponding results in 80%. PCR-mediated detection of cancer cells was confirmed by culture technique and light microscopy, however, further comparison of CK19-PCR with standard techniques like cell culture and immunocytochemistry is still necessary.

Impact of fluorodeoxyglucose positron emission tomography on the clinical management of patients with glioma

The past decade has seen the identification of many clinical settings in the treatment of primary brain tumors in which information from fluorodeoxyglucose positron emission tomography (FDG-PET) might be useful, if not essential, to therapeutic formulation. FDG-PET is currently used at referral centers in the management of primary brain tumors. The clinical pattern of FDG-PET use was assessed and its value compared to other information sources in clinical decision making. The clinical records of 75 glioma patients who were evaluated by FDG-PET were reviewed. The range of circumstances in which FDG-PET was employed included: pretherapeutic baseline studies for monitoring the effect of a therapy (1% of all cases), mapping of hypermetabolic regions before surgery or biopsy (2%), mapping of hypermetabolic regions before radiotherapy (2%), postsurgical evaluation for residual tumor (2%), assessment of the malignancy of a mass as a substitute for biopsy (11%), and distinguishing between radiation necrosis and recurrent tumor (87%). Other sources of information that contributed to the therapeutic management of patients included: gadolinium-enhanced MRI, contrast-CT, and clinical findings.

Performance of flexible sigmoidoscopy by a clinical nurse specialist

According to the National Cancer Institute, 138,200 new cases and more than 55,000 deaths from colorectal cancer occurred in the U.S. in 1995. A high percentage of early cancers can be detected by screening asymptomatic persons older than age 50 with a digital rectal exam, fecal occult blood testing, and sigmoidoscopy. Evidence suggests that a decrease in mortality from colorectal cancer is associated with regular screening by sigmoidoscopy in an average risk population. As the population ages, more persons are eligible for colorectal cancer screening. Physician endoscopists are not available in all areas, and changes in reimbursement rates have caused some to discontinue this service. For these reasons, the Veterans Administration Medical Center in Buffalo, NY, developed a Colorectal Cancer Screening Program managed by a gastroenterology Clinical Nurse Specialist (CNS). Through study and supervision, the CNS has become proficient in the performance of 60-cm flexible sigmoidoscopic techniques and the diagnosis of multiple colon disorders, including sessile and pedunculated polyps, diverticulosis, tumors, hemorrhoids, and other conditions.

Transition rate kinetics from ethanol oxidation to glucose utilisation within a structured model of baker's yeast

The transition rate kinetics from ethanol oxidation to glucose utilisation, within a structured model of baker's yeast, described previously, were experimentally identified. The shift in metabolism has been assessed through glucose pulses during batch growth on ethanol. The influence of glucose concentration (between 0.25 g l-1 and 0.90 g l-1) and initial biomass concentration (between 0.61 g l-1 and 1.44 g l-1) on the transition rate was determined. The transition rate can not be described by a first-order saturation-type kinetics with respect to glucose only. A corrective term, which takes into account biomass concentration should be included.

A case-control study to examine the influence of maternal perinatal behaviors on the incidence of Crohn's disease

This case-control study, which examines maternal perinatal characteristics and behaviors during pregnancy, was an initial step to determine whether an association exists between breast feeding, oral contraceptive use, smoking habits during pregnancy, and the incidence of Crohn's disease. The population studied was mothers whose children were diagnosed with Crohn's disease before the age of 22. Population controls were selected by each case mother, who solicited two friends or neighbors with a child of similar age. Case mothers differed significantly on the variables of allergies (p = .05) and family history of inflammatory bowel disease (p = .001). No significant differences were found regarding feeding, oral contraceptives, or smoking. Using a forward step-wise logistic regression method, only family history remained in the equation.

Properties of bispecific single chain antibodies expressed in Escherichia coli

Single chain bispecific antibodies, in which the genes that encode the VH and VL regions are linked in tandem, may offer some advantages over other methods of bispecific antibody preparation. To begin to evaluate the potential of this system, a single chain bispecific antibody (scFv2) that binds to the T cell receptor of a cytotoxic T cell clone and to the hapten fluorescein was constructed. The individual scFv regions were joined by a 25 amino acid linker, and the scFv2 protein was obtained from insoluble inclusion bodies after guanidine solubilization and refolding. Fluorescein-purified scFv2 is active at concentrations of approximately 10 nM (approximately 1 microgram/ml) and above in mediating lysis of fluorescein-coupled tumor cells by the cytotoxic T lymphocytes (CTL). This system has now been used to evaluate various features of the scFv2 approach: (a) affinities of the scFv2 for the TCR and fluorescein, (b) yields of the scFv2 from several different purification schemes, (c) relationship of antigen density (i.e., fluorescein density on tumor cells) to the ability to redirect lysis of the tumor cell, and (d) relationship of scFv2 affinity for the tumor antigen to the ability to redirect lysis. This study was performed by using several analogs of fluorescein for which the scFv2 had different affinities. Results showed that it should be possible to select antibodies with appropriate affinities such that tumor cells with typical antigen densities of 10(4)-10(5) molecules per cell will be lysed and normal cells that have lower levels of the antigen will be spared.

Personality self-representations of patients with hand injury, and its relationship with work injury

This study compared the personality self-representations of 288 hand injured patients with those of 959 young people (15-25 years old) randomly selected from the general population (noted GP), and with those of 336 unemployed people of all ages in professional training (U) in Lorraine (north-eastern France). The relationship between patients' personality self-representations and injury was also investigated. Personality self-representations included 14 questions: in your own opinion are you sociable?, at ease with others?, serious?, careful?, dynamic?, optimistic?, worried?, irritable?, clumsy?, solitary?, organised?, ambitious?, do you have a sense of responsibility?, and many plans? The patients had similar self-representations to GP except for the items non clumsy (odds ratio adjusted on age and sex OR = 2.40, p < 0.05) and optimistic (OR = 1.70, but 0.05 < p < 0.10). The frequencies of non irritable, non clumsy and non solitary people were higher in patients than in the U group (OR about 2.40, p < 0.01). By contrast, the other items were more favourable for the U group except for the items sociable, organised and having many plans. Self-representation items were significantly related to some socio-demographic data. The work injured workmen having one or more previous work injuries during the last five years were more at ease with others than the other subjects. Among the work injured workmen who had had no previous work injury during this time, the people aged 29 or less (the highest risk age class) were more optimistic than the others (71% vs 49%, p < 0.05); a difference was also found for the items at ease with others, careful, dynamic, and non worried, but it was not significant possibly due to the small number of subjects. The sum of these five items differed between the two age groups (3.29 +/- 1.49 vs 2.55 +/- 1.68, p < 0.05). These simple items would provide an interesting approach in terms of personality which could explain in part the excess of work injuries in young people, though the work requirement still seemed to be the highest risk factor.

Electrocautery and patients with implanted cardiac devices

Implanted cardiac devices, pacemakers, and automatic cardioverter/defibrillators are becoming more common in the general population. There are more than one-half million persons with pacemakers living in North America, and approximately 20,000 patients have received automatic implantable cardioverter/defibrillators. As pacemaker and defibrillator patients experience common gastrointestinal afflictions, it is likely that more will require endoscopic procedures. Appropriate precautions must be undertaken during electrosurgical procedures in order to avoid damage and interruption of pacemaker/defibrillator devices. Through careful assessment, intervention, and discharge planning, the GI nurse and associate can reduce electrosurgical risks to the gastrointestinal patient with an implanted cardiac device. Specific recommendations for preprocedure patient assessment and intraprocedure interventions are discussed, and an actual case is presented to illustrate a successful plan of care.

Chemo-somatosensory event-related potentials in response to repetitive painful chemical stimulation of the nasal mucosa

The aim of the study was to investigate how chemo-somatosensory event-related potentials (CSSERPs) and pain ratings are modified by repetitive painful stimulation of the nasal mucosa (58% v/v CO2, 200 msec duration). Twenty-two subjects performed 3 experiments during which trains of stimuli were applied. The interstimulus interval (ISI) between stimuli was constant for each experiment, but varied between experiments (8, 4, and 2 sec). CSSERPs were obtained from 5 positions (Fz, C3, Cz, C4, and Pz). The subjects not only rated the overall perceived intensities but also reported the quality of the stimuli. At an ISI of 8 sec estimates decreased and only stinging sensations were reported. In contrast, at an interval of 2 sec estimates increased being accompanied by the buildup of burning pain. This phenomenon was interpreted in terms of the superposition of first (sharp and stinging pain: A delta fibers) and second pain (dull and burning pain: C fibers), respectively. However, given the special circumstances of short ISIs CSSERP amplitudes decreased the more the shorter the ISI was. In line with previous investigations it is hypothesised that CSSERPs predominantly reflect nociceptive information transmitted via A delta fibers.

Efficient tumor cell lysis mediated by a bispecific single chain antibody expressed in Escherichia coli

Recent advances in the expression of Abs in Escherichia coli have raised the possibility that virtually any specificity can be obtained by either cloning Ab genes from characterized hybridomas or by de novo selection using Ab gene libraries. Bispecific Abs have been more difficult to engineer because of problems inherent in the proper folding and association of VH and VL domains. In this report, a model system for expressing and testing the activity of a single chain bispecific Ab was used. The Ab contained the VH and VL genes from the anti-TCR Ab 1B2 joined by a 25 amino acid residue linker to the VH and VL genes from the anti-fluorescein Ab 4420. The 57-kDa single chain bispecific Ab (scFv2) was purified in a single step by affinity chromatography through a fluorescein column at a yield of 1 mg/L of bacterial culture. Despite the presence of 1B2 V regions at the NH2-terminus and a 10-residue c-myc peptide at the COOH-terminus, the refolded protein had an affinity for fluorescein that was nearly identical with the monospecific single chain Ab. The scFv2 also bound the TCR of the mouse CTL clone 2C and redirected the lysis of human tumor cells that had fluorescein covalently linked to their surface. Lysis was mediated at scFv2 concentrations that were 100-fold lower than the concentrations of Ab that inhibited normal recognition by CTL 2C. These results show that single chain bispecific Abs can mediate CTL lysis of target cells without the immunosuppressive side effects associated with the use of anti-TCR Abs.

Efficient tumor cell lysis mediated by a bispecific single chain antibody expressed in Escherichia coli

Recent advances in the expression of Abs in Escherichia coli have raised the possibility that virtually any specificity can be obtained by either cloning Ab genes from characterized hybridomas or by de novo selection using Ab gene libraries. Bispecific Abs have been more difficult to engineer because of problems inherent in the proper folding and association of VH and VL domains. In this report, a model system for expressing and testing the activity of a single chain bispecific Ab was used. The Ab contained the VH and VL genes from the anti-TCR Ab 1B2 joined by a 25 amino acid residue linker to the VH and VL genes from the anti-fluorescein Ab 4420. The 57-kDa single chain bispecific Ab (scFv2) was purified in a single step by affinity chromatography through a fluorescein column at a yield of 1 mg/L of bacterial culture. Despite the presence of 1B2 V regions at the NH2-terminus and a 10-residue c-myc peptide at the COOH-terminus, the refolded protein had an affinity for fluorescein that was nearly identical with the monospecific single chain Ab. The scFv2 also bound the TCR of the mouse CTL clone 2C and redirected the lysis of human tumor cells that had fluorescein covalently linked to their surface. Lysis was mediated at scFv2 concentrations that were 100-fold lower than the concentrations of Ab that inhibited normal recognition by CTL 2C. These results show that single chain bispecific Abs can mediate CTL lysis of target cells without the immunosuppressive side effects associated with the use of anti-TCR Abs.