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Biomedical subjects

F T Peters

Publications and source records attributed to F T Peters.

At least 19 recordsLinked to original sources
PubMed2003

Prevalence of illicit drug use in plasmapheresis donors.

BACKGROUND AND OBJECTIVES: No data are presently available concerning the frequency of illicit drug use in plasmapheresis donors. We therefore examined source plasma units produced in the United States (US) and in Germany for evidence of illicit drug use among donors. MATERIALS AND METHODS: Seventy-five US plasma units from 10 different US states and 75 German plasma units that had been analysed principally for their protein composition were screened for drugs. Determinations were made, using automated immunoassays, of the presence of cannabis, cocaine, amphetamine, methamphetamine, methylenedioxymethamphetamine (MDMA), methylenedioxyethylamphetamine (MDE) and opiates. Positive results were confirmed by gas chromatography-mass spectrometry. RESULTS: Eleven US plasma units were found to be positive for cocaine (14.6%), whereas all German samples were cocaine negative (P = 0.0007). Fifteen US plasma units (20%) and one German unit (1.3%) were confirmed as positive for cannabis (P = 0.0003). Three out of 75 US plasma units were positive for both cannabis and cocaine. In none of the 150 samples were amphetamine, methamphetamine, MDMA, MDE or opiates detected. CONCLUSIONS: Our results strongly suggest differences in cocaine and cannabis consumption between US and German plasmapheresis donors. If these results are confirmed by larger-scale studies, random drug screening (including cocaine) of donors should be implemented in order to reduce the number of drug-containing plasma units, especially in the USA.

Blood Donors↗
PubMed2001

Validated gas chromatographic-mass spectrometric assay for determination of the antifreezes ethylene glycol and diethylene glycol in human plasma after microwave-assisted pivalylation.

A gas chromatographic-mass spectrometric assay is described for identification and quantification of the antifreezes ethylene glycol (EG) and diethylene glycol (DEG) in plasma for early diagnosis of a glycol intoxication. After addition of 1,3-propanediol as internal standard, the plasma sample was deproteinized by acetone and an aliquot of the supernatant was evaporated followed by microwave-assisted pivalylation. After gas chromatographic separation, the glycols were first identified by comparison of the full mass spectra with reference spectra and then quantified. The quantification has been validated according to the criteria established by the Journal of Chromatography B. The assay was found to be selective. The calibration curves for EG and DEG were linear from 0.1 g/l to 1.0 g/l. The limit of detection for EG and DEG was 0.01 g/l and the limit of quantification for both was 0.1 g/l. The absolute recoveries were 50 and 65% for the low quality control samples and 51 and 73% for the high quality control samples of EG and DEG, respectively. Intra- and inter-day accuracy and precision were inside the required limits. The glycols in frozen plasma samples were stable for more than 6 months. The method was successfully applied to several authentic plasma samples from patients intoxicated with glycols. It has also been suitable for analysis of EG and DEG in urine.

Ethylene Glycol↗
PubMed2001

Recurrent severe bleeding from gastrointestinal angiodysplasia in a patient with von Willebrand's disease, controlled with recombinant factor VIIa.

A patient with von Willebrand's disease had recurrent gastrointestinal bleeding from angiodysplasia, with inadequate response to von Willebrand factor substitution, medical and endoscopic treatment, and resection of affected bowel. Frequent blood transfusions were required. She started home treatment with recombinant activated factor VII (rFVIIa) at the onset of bleeding, in addition to her standard therapy. From then on, bleeds could be controlled rapidly and no more blood transfusions were needed. We conclude that rFVIIa is effective in this case of angiodysplasia and might be a therapeutic option in similar patients.

Angiodysplasia↗
PubMed2000

Toxicokinetics and analytical toxicology of amphetamine-derived designer drugs ('Ecstasy').

The phase I and II metabolites of the designer drugs methylenedioxyamphetamine (MDA), R,S-methylenedioxymethamphetamine (MDMA), R,S-methylenedioxyethylamphetamine (MDE), R, S-benzodioxazolylbutanamine (BDB) and R, S-N-methyl-benzodioxazolylbutanamine (MBDB) were identified by gas chromatography-mass spectrometry (GC-MS) or liquid chromotography-mass spectrometry (LC-MS) in urine and liver microsomes of humans and rats. Two overlapping pathways could be postulated: (1) demethylenation followed by catechol-O-methyl-transferase (COMT) catalyzed methylation and/or glucuronidation/sulfatation; (2) N-dealkylation, deamination and only for MDA, MDMA, MDE oxidation to the corresponding benzoic acid derivatives conjugated with glycine. Demethylenation was mainly catalyzed by CYP2D1/6 or CYP3A2/4, but also by CYP independent mechanisms. In humans, MDMA and MBDB could also be demethylenated by CYP1A2. N-demethylation was mainly catalyzed by CYP1A2, N-deethylation by CYP3A2/4. Based on these studies, GC-MS procedures were developed for the toxicological analysis in urine and plasma. Finally, toxicokinetic parameters are reviewed.

Amphetamines↗
PubMed2000

Effect of elimination of acid reflux on epithelial cell proliferative activity of Barrett esophagus.

BACKGROUND: Barrett esophagus (BE) is a premalignant condition resulting from chronic acid gastroesophageal reflux and is associated with increased epithelial cell proliferation. Elimination of acid reflux might decrease cancer risk by affecting cell proliferation in BE. The effect of elimination of acid reflux on epithelial cell proliferation in BE was studied. METHODS: Forty-five patients with long segment Barrett esophagus were treated in a randomized 2-year follow-up study with either omeprazole 40 mg b.i.d. (OME) or ranitidine 150 mg b.i.d. (RAN) and were compared for the effect on epithelial cell proliferation. Biopsies were taken 3 cm above the GE junction and just below the Z-line, at 0, 3, 9, and 24 months. Epithelial cell proliferation was determined by in vitro labeling with 5-bromo-2-deoxyuridine and immunohistochemistry. Labeling indices (LI) were established for luminal and crypt epithelium separately. Ambulatory 24-h esophageal pH-metry was performed at 0 and 3 months. Comparisons were made for the timeframes 0-3 months, 3-24 months, and 0-24 months. RESULTS: OME reduced mean acid reflux to 0.1 %/24 h, RAN to 9.4%. In the distal and the proximal biopsies, change in LI after 3 months was n.s. at either level for both treatments. In the distal biopsies (OME 22, RAN 23 patients) luminal LI increased significantly for RAN from 3 to 24 months (+12.64% month, mean area under the curve (AUC)), while that for OME remained stable, RAN versus OME P < 0.05. Crypt LI increased in both groups, only in RAN significantly so (+30.75% month), RAN versus OME n.s. In the proximal biopsies luminal LI at 24 months (OME 20, RAN 21 patients) had increased slightly but not significantly in RAN (+8.86% month), RAN versus OME n.s., whereas in the crypts LI in OME it had increased significantly (+28.80% month), OME versus RAN n.s. CONCLUSION: Elimination of acid reflux resulted in a stabilization of luminal cell proliferative activity of Barrett epithelium in the distal esophagus, whereas this activity increased during continued acid reflux. Whether this finding has any implication for the cancer risk in Barrett esophagus remains to be seen.

Adult↗
PubMed1999

The influence of Helicobacter pylori on oesophageal acid exposure in GERD during acid suppressive therapy.

BACKGROUND: Helicobacter pylori exaggerates the effect of acid suppressive drugs on intragastric pH. It is unknown whether this is relevant for the treatment of GERD. AIM: To compare oesophageal acid exposure and symptoms in H. pylori-negative and H. pylori-positive GERD patients during low and profound acid suppression. METHODS: Barrett's oesophagus patients with gastro- oesophageal acid reflux were studied by 24-h oesophageal pH-metry at baseline and during randomized treatment with omeprazole 40 mg b.d. or ranitidine 150 mg b.d. H. pylori status was determined by a serum IgG ELISA. Symptoms were scored on a four-graded scale. RESULTS: Of 58 patients, 26 (14 H. pylori-negative, 12 H. pylori-positive) were randomized to omeprazole, 32 (16 H. pylori-negative, 16 H. pylori-positive) to ranitidine. At baseline, oesophageal acid exposure and symptoms did not differ between H. pylori-negative and H. pylori-positive: mean time proportion pH < 4 per 24 h was 16.1% (95% CI 11.5-23.2) in H. pylori-negative, and 15.8% (11.3-21.4) in H. pylori-positive patients. Omeprazole treatment resulted in a decrease of acid reflux per 24 h from 23.4% (7.9-39.3) to 0.0% (0.0-2.9) in H. pylori-negative, and from 17.3% (8.9-38.8) to 0.1% (0.0-1.7) in H. pylori-positive patients; ranitidine resulted in a decrease from 14.4% (10.5-18.5) to 9.3% (5.6-12.8) in H. pylori-negative, and from 15.1% (9.8-21.0) to 9.0% (3.1-20.1) in H. pylori-positive patients, the difference between H. pylori-negative and H. pylori-positive patients being N.S. There was no significant difference between H. pylori-negative and H. pylori-positive patients with respect to erect and supine acid reflux, or symptom scores in both treatment groups. CONCLUSIONS: H. pylori infection does not influence oesophageal acid reflux and symptoms in patients with Barrett's oesophagus, either at baseline or during low as well as profound acid suppressive therapy. We conclude that the dose of acid suppression does not have to be titrated upon H. pylori status in GERD.

Adult↗
PubMed1999

Endoscopic regression of Barrett's oesophagus during omeprazole treatment; a randomised double blind study.

BACKGROUND: Barrett's oesophagus, columnar metaplasia of the epithelium, is a premalignant condition with a 50-100-fold increased risk of cancer. The condition is caused by chronic gastro-oesophageal reflux. Regression of metaplasia may decrease the cancer risk. AIMS: To determine whether elimination of acid gastro-oesophageal reflux induces a regression of metaplastic epithelium. METHODS: Sixty eight patients with acid reflux and proven Barrett's oesophagus were included in a prospective, randomised, double blind study with parallel groups, and were treated with profound acid secretion suppression with omeprazole 40 mg twice daily, or with mild acid secretion suppression with ranitidine 150 mg twice daily, for 24 months. Endoscopy was performed at 0, 3, 9, 15, and 24 months with measurement of length and surface area of Barrett's oesophagus; pH-metry was performed at 0 and 3 months. Per protocol analysis was performed on 26 patients treated with omeprazole, and 27 patients treated with ranitidine. RESULTS: Omeprazole reduced reflux to 0.1%, ranitidine to 9.4% per 24 hours. Symptoms were ameliorated in both groups. There was a small, but statistically significant regression of Barrett's oesophagus in the omeprazole group, both in length and in area. No change was observed in the ranitidine group. The difference between the regression in the omeprazole and ranitidine group was statistically significant for the area of Barrett's oesophagus (p=0. 02), and showed a trend in the same direction for the length of Barrett's oesophagus (p=0.06). CONCLUSIONS: Profound suppression of acid secretion, leading to elimination of acid reflux, induces partial regression of Barrett's oesophagus.

Adult↗
PubMed1998

Epithelial cell proliferative activity of Barrett's esophagus: methodology and correlation with traditional cancer risk markers.

Barrett's esophagus (BE) is a premalignant condition, due to chronic gastroesophageal reflux. Effective antireflux therapy may diminish cancer risk. To evaluate this option an intermediate marker is needed. We developed a methodology for measurement of epithelial cell proliferative activity of Barrett's mucosa as an intermediate marker and correlated the activity with traditional cancer risk markers and other parameters. Fifty-six patients (21-74 years of age) with Barrett's esophagus and established acid gastroesophageal reflux were included. Biopsies were taken from Barrett's mucosa at 3-cm intervals. Reflux was measured by 24-hr pH-metry. Proliferative activity was determined using in vitro labeling with 5-bromodeoxyuridine and immunohistochemistry and was expressed as labeling index (LI). The length of BE correlated with erect acid reflux (P=0.002). LI in specialized columnar metaplasia was higher than in gastric metaplasia, especially in crypt epithelium (P < 0.05). Multiple regression analysis revealed independent positive correlations for surface LI with dysplasia (P=0.011), distance from the incisors (P=0.041), and crypt LI (P=0.000). Crypt LI showed an independent positive correlation with the length of BE (P=0.033) and type of metaplasia (P=0.007). In conclusion, epithelial cell proliferative activity of BE correlates with several known risk factors for cancer. Proliferative activity is an attractive intermediate marker to evaluate the effects of interventional measures to decrease cancer risk in Barrett's esophagus.

Adenocarcinoma↗
PubMed1998

Gastric asthma: a pathophysiological entity?

BACKGROUND: Gastro-oesophageal reflux disease (GORD) is manifested by typical reflux symptoms and atypical extra-oesophageal symptoms. Important in this respect are respiratory conditions. Gastric asthma is a prominent example of these extra-oesophageal manifestations of GORD. There is, however, much debate about its prevalence, pathophysiology and clinical importance. METHODS: Narrative review of the literature. RESULTS: In asthmatics, the prevalence of GORD is generally reported to be higher than in normals, but with a wide range, probably due to patient selection. In a minority of asthmatics GORD aggravates or triggers asthma. The pathogenetic mechanisms can be a vagally transmitted reflex as well as micro-aspiration of refluxed material. The association with inflammatory mediator release has been insufficiently investigated. Selecting those who are likely to respond to anti-reflux measures is important: those with difficult to treat asthma, non-allergic asthma, adult-onset asthma with GORD. Oesophageal pH-metry to prove GORD and gastroscopy to diagnose Barrett's metaplasia are advisable.

Anti-Asthmatic Agents↗
PubMed1998

No effects of high-dose omeprazole in patients with severe airway hyperresponsiveness and (a)symptomatic gastro-oesophageal reflux.

Acid gastro-oesophageal reflux may aggravate respiratory symptoms in patients with asthma and chronic obstructive pulmonary disease (COPD) by increasing airway hyperresponsiveness through vagally-mediated pathways. We wanted to determine whether elimination of acid reflux could improve symptoms in such patients. In a randomized, double-blind, placebo-controlled study, 36 allergic and nonallergic subjects (17 males and 19 females, mean age 52 yrs), with airway obstruction and severe airway hyperresponsiveness despite maintenance treatment with an inhaled corticosteroid and with increased acid gastro-oesophageal reflux, were treated either with omeprazole, 40 mg b.i.d., or placebo for 3 months. Primary endpoints were: airway hyperresponsiveness, as determined by the provocative concentration of methacholine producing a 20% fall in forced expiratory volume in one second (PC20); and airway obstruction. Secondary endpoints were: peak expiratory flow variability; reversibility to inhaled ipratropium bromide as a parameter of vagal activity; asthma symptoms scores; and medication used. Reflux was measured by 24 h ambulatory intraoesophageal pH measurement. Omeprazole, 40 mg b.i.d., for 3 months had no beneficial effect on any of the pulmonary parameters, despite its profound effect on acid reflux and improvement of reflux symptoms scores, compared to placebo. The results of this study do not support a role for intensive antireflux therapy to improve pulmonary symptoms and function in patients with asthma and chronic obstructive pulmonary disease, who have severe airway hyperresponsiveness despite maintenance treatment with inhaled corticosteroids.

Adolescent↗
PubMed1993

[Amyloidosis as cause of severe abdominal symptoms in a young Somali immigrant?].

Extensive deposition of amyloid was detected in the digestive tract of a Somali woman aged 20 yr with abdominal pain, diarrhoea and cachexia. Immunohistochemical characterisation showed that the amyloid protein involved was of the AA type. Elevated levels were also found for serum amyloid A (SAA), an acute-phase protein which is the precursor of AA amyloid. The underlying inflammatory disease was peritoneal tuberculosis. The normalisation of the SAA levels and the recovery of the small intestine during tuberculostatic therapy showed that the tuberculosis was the cause of the enteropathy. This case report highlights the importance of early detection and effective treatment of the underlying inflammatory disease in case of AA amyloidosis.

Adult↗
PubMed1993

Is chemotherapy associated with development of Barrett's esophagus?

Columnar-lined or Barrett's esophagus is a premalignant condition. It is almost unvariably due to chronic gastroesophageal reflux. Since there are some reports that Barrett's esophagus can be induced by chemotherapy, we investigated 20 male patients, treated with chemotherapy for testicular cancer, and 18 female patients, treated with high-dose chemotherapy for breast cancer. Only one patient in the testicular cancer group had Barrett's esophagus of the circumferential type, in addition to typical reflux esophagitis and a hiatal hernia four years after chemotherapy. In the breast cancer group one patient had an indeterminate junction. Our results do not support the hypothesis that chemotherapy poses a substantially increased risk for the development of Barrett's esophagus.

Adult↗
PubMed1993

Barrett's oesophagus and carcinoma. Recent insights into its development and possible prevention.

Barrett's oesophagus or columnar epithelium-lined oesophagus is a condition due to chronic gastro-oesophageal reflux. In addition to acid-peptic reflux, reflux of duodenal contents may have a role in its aetiology. The clinical importance of Barrett's oesophagus is the increased risk for development of oesophageal adenocarcinoma. Measures to prevent cancer development have so far been limited to regular screening and early oesophagectomy in the case of severe dysplasia or early cancer. Other modes of intervention, directed toward prevention of dysplasia and possibly regression of Barrett's epithelium, should be sought. Early markers of development toward dysplasia and cancer are necessary if we are to be able to evaluate such measures. Determination of epithelial cell proliferative activity has the potential to be such a marker. A study is now being performed to evaluate the effect of elimination of acid reflux on proliferative activity of Barrett's epithelium in conjunction with the effects of inflammation and development of dysplasia.

Adenocarcinoma↗
PubMed1992

Intestinal pseudo-obstruction in myotonic dystrophy.

We describe four myotonic dystrophy (DM) patients who developed recurrent intestinal pseudo-obstruction. Some episodes were associated with gastroenteritis, while abdominal crowding may have occurred in one case during the third trimester of pregnancy. In most instances, however, no apparent cause could be identified. Intestinal pseudo-obstruction may occur at any stage of DM. In one of our cases intestinal pseudo-obstruction preceded significant muscle weakness by 15 years. Intestinal pseudo-obstruction is usually treated effectively with conservative measures. These include restriction of oral intake, intravenous fluids, and multiple enemas or colonoscopy. Improved intestinal function was noted in one case treated with the prokinetic agent cisapride. A partial sigmoid resection was performed in three cases with dolichomegacolon. No abnormalities were reported on histological examination. Since intestinal pseudo-obstruction is a rare complication of DM, it is of interest that two of our cases are sibs. Review of published reports showed several reports of familial occurrence of specific complications. These include cardiac conduction disturbances, focal myocarditis, mitral valve prolapse, pilomatrixomas, polyneuropathy, normal pressure hydrocephalus, and dilatation of the urinary tract. Myotonic dystrophy may show a tendency to familial clustering of organ specific involvement.

Adult↗