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Biomedical subjects

W Hoffmann

Publications and source records attributed to W Hoffmann.

At least 91 records · Page 5Linked to original sources
PubMed1998

Radiation-induced gastrointestinal toxicity. Pathophysiology, approaches to treatment and prophylaxis.

BACKGROUND: Gastrointestinal toxicity is frequently observed during radiotherapy of malignancies in the abdomen and pelvis. The proposed pathophysiology of radiation enteritis is complex and a variety of different treatment strategies have been suggested for the management of acute radiation-induced diarrhea. MATERIAL AND METHODS: Data are presented from an extensive review of the current literature. RESULTS: Radiation-induced diarrhea results from a variety of different pathophysiological mechanisms including malabsorption of bile salts and lactose, imbalances in local bacterial flora and changes in the intestinal patterns of motility. Up to date acute radiation diarrhea is predominantly treated symptomatically using opioide derivates (loperamide) or adsorbants of bile salts such as smectite. Clinical trials have been performed using L. acidophilus, smectite or sucralfate for diarrhea prophylaxis with moderate reduction of acute symptoms. CONCLUSIONS: Further evaluation of strategies for diarrhea prophylaxis is warranted. Due to the complex nature of radiation enteritis a multimodal approach taking into account alterations in intestinal motility patterns, malabsorption of bile salts and an imbalance of mucosal bacterial flora may offer new perspectives.

Abdominal Neoplasms↗
PubMed1997

[Role of sodium selenite as an adjuvant in radiotherapy of rectal carcinoma].

BACKGROUND: In various epidemiologic studies an association of low selenium blood levels and reduced glutathione peroxidase with an increased risk of cancer incidence was described. The antitumoral therapy and a suboptimal nutrition could intensify this deficiency. Every reduction of disease related and therapeutic caused symptoms may improve life quality. APPLICATION: We report our preliminary experiences in the adjuvant radiochemotherapy of advanced rectal cancer (UICC II/III) corresponding to the NCl recommendation. An oral selenium supplementation was carried out with 2000 micrograms Na2SeO3 after every course of fluorouracil chemotherapy and daily 400 micrograms Na2SeO3 after irradiation of tumor region and lymph nodes. A weekly life quality assessment was explored with special interest in diarrhea, dysurie, pain, appetite, nausea and emesis. CONCLUSION: Damages to normal tissue specially to DNA enzymes and membranes caused by free radicals is one mechanism in tumorgenesis, tumor progression and therapeutic consequence. A radioprotective effect of selenium is verified by in vitro and in vivo data. Our data show that oral selenium intake in rectal cancer patients is easily tolerated with no side effects. Improving life quality and secondary cancer prevention with supplementation of selenium has to be proven in prospective randomized studies.

Antioxidants↗
PubMed1997

Radiotherapy and concomitant weekly 1-hour infusion of paclitaxel in the treatment of head and neck cancer--results from a Phase I trial.

PURPOSE: To define the maximum tolerated dose (MTD) by describing the dose-limiting toxicity (DLT) of weekly paclitaxel (PAC) given as a 1-h I.V. infusion in patients with head and neck cancer concomitant to irradiation. METHODS AND MATERIALS: Patients with unresectable or incompletely resected head and neck cancer were enrolled into a prospective, dose-escalating Phase I study. Toxicity was graded according to the WHO toxicity score. MTD dose was defined when two out of six patients developed DLT. The starting dose of PAC was 20 mg/m2 once weekly I.V. over 60 min, with a subsequent dose escalation of 10 mg/m2 in cohorts of three new patients. Radiation therapy was administered in three field technique over 6-7 weeks in 2.0 Gy/daily fractions for 5 consecutive days/week up to total doses of 60-70 Gy. RESULTS: From 1994-1996, 18 patients completing three dose levels were included into the study. Altogether, 101 courses of chemotherapy were evaluable for toxicity. On the second dose level (30 mg/m2) one of three patients experienced DLT with Grade IV mucositis. On the next dose level with 40 mg/m2 PAC weekly one patient experienced DLT being prolonged Grade III mucositis. From the following three patients required, two patients showed no DLT. The third patient showed mucositis of WHO Grade 4 and died from hemorrhage caused by a rupture of the a pharyngeal wall. Dose level 2 (30 mg/m2) was repeated and one of the three newly treated patients again suffered from mucositis WHO Grade 4. CONCLUSION: When PAC is given weekly as a 1-h infusion concomitant to radiotherapy, MTD is 30 mg/m2 with mucositis being DLT; hematological and further nonhematological toxicity is mild.

Adult↗
PubMed1997

Rolling in the clover: trefoil factor family (TFF)-domain peptides, cell migration and cancer.

Trefoil factor family (TFF)-domain peptides 1-3 are mucin-associated molecules, largely found in epithelia of gastrointestinal tissues. Structurally similar, resistant to enzymatic degradation, they are up-regulated around areas of epithelial damage such as ulcers. Transgenic expression or exogenous peptide ameliorates or prevents gastric mucosal damage due to indomethacin and some are rapidly up-regulated after cryogenic burns. A role in promoting cell migration is strongly suggested. Knockout mice lacking TFF1 or TFF3 show significant pathology, with the former developing gastric tumours. A recent Conference Philippe Laudat agreed upon a new nomenclature for these peptides.

Animals↗
PubMed1997

Similarities of integumentary mucin B.1 from Xenopus laevis and prepro-von Willebrand factor at their amino-terminal regions.

Frog integumentary mucin B.1 (FIM-B.1) contains various cysteine-rich modules. In the past, a COOH-terminal "cystine knot" motif has been found that is similar to von Willebrand factor; this region is generally known to be responsible for dimerization processes. Furthermore, a "complement control protein" motif is present as an internal cysteine-rich domain in FIM-B.1. We characterize here the missing 75% toward the NH2 terminus of the FIM-B.1 precursor by molecular cloning. Analogous to prepro-von Willebrand factor, four elements with considerable similarity to D-domains are present (i.e. D1-D2-D'-D3). These domains have been described as essential for the multimerization of von Willebrand factor. Thus, the general structure of FIM-B.1 resembles that of the human mucin MUC2 as well as prepro-von Willebrand factor; these three molecules at least seem to share common structural elements allowing similar multimerization mechanisms.

Amino Acid Sequence↗
PubMed1997

Intestinal trefoil factor (TFF 3) and pS2 (TFF 1), but not spasmolytic polypeptide (TFF 2) mRNAs are co-expressed in normal, hyperplastic, and neoplastic human breast epithelium.

pS2-TFF 1 is expressed in breast cancers and has been investigated as a potential prognostic factor reflecting oestrogen dependence. The relationship to the expression of other trefoil peptides, human spasmolytic polypeptide (hSP-TFF 2) and intestinal trefoil factor (hITF/hPI.B-TFF 3) is documented here. Fifty-seven breast specimens were selected from surgical pathology archives and included five normal breasts (two lactating), seven benign proliferative lesions, 11 ductal carcinomas in situ (DCIS), three lobular carcinomas in situ (LCIS), 24 invasive ductal carcinomas (IDC), and seven invasive lobular carcinomas (ILC). The comparative distribution of trefoil mRNAs was assessed by in situ hybridization using 35S-labelled riboprobes and immunohistochemical staining for pS2-TFF 1 and hSP-TFF 2. pS2-TFF 1 and hITF/hPI.B-TFF 3 mRNA were focally present at low signal intensity in normal and benign breast. Both pS2-TFF 1 and hITF/hPI.B-TFF 3 were expressed in all DCIS, LCIS and ILC, and 21/24 IDC. Overall, expression patterns of pS2-TFF 1 and hITF/hPI.B-TFF 3 coincided, but hITF/hPI.B-TFF 3 mRNA was usually found in a greater proportion of cells. Expression of hSP-TFF 2 peptide or mRNA was not detected in any of these cases. MCF 7 breast carcinoma cells also expressed hITF/hPI.B-TFF 3 and pS2-TFF 1 mRNAs but not hSP-TFF 2. hITF/hPI.B-TFF 3 co-expression with pS2-TFF 1 may act as a prognostic factor, but also raises questions about the regulatory pathway for pS2-TFF 1 hITF/hPI.B-TFF 3. Trefoil factors have effects on cell motility and spreading in vitro, and co-expression of hITF/hPI.B-TFF 3 with pS2-TFF 1 could be functionally significant if they form a heterodimer or compete for receptor binding. Absence of hSP-TFF 2 expression may be of equal relevance to tumour cell biology.

Blotting, Northern↗
PubMed1997

[The use of sucralfate in radiation oncology].

PURPOSE: Radiotherapy, a cornerstone in the management of head and neck cancer, pelvic cancer, and esophageal cancer is associated with a marked mucosal toxicity. Pain, malnutrition and diarrhea are the most prevalent clinical symptoms of radiation induced mucosal damage. Because there is no known way to obviate radiation mucositis all efforts to prevent aggravation and accelerate healing of mucosal changes are of great importance. Numerous agents including antimicrobials, local and systemic analgesics, antiinflammatory drugs, antidiarrheal drugs, in combination with intensive dietetic care are used to relieve symptoms. Recently coating agents like the polyaluminum-sucrose complex sucralfate were suggested for the prevention and treatment of mucosal reactions. Since sucralfate protects ulcerated epithelium by coating, liberates protective prostaglandins and increases the local availability of protective factors this drug might directly interact with the pathogenesis of mucositis. PATIENTS AND METHOD: The results of available studies are analysed and discussed. RESULTS: The results of several studies indicate that sucralfate treatment especially during radiotherapy for pelvic cancer leads to a significant amelioration of clinical symptoms and morphological changes. An application of sucralfate during radiotherapy of head and neck cancer reveals only limited benefits in most studies performed. CONCLUSION: Nevertheless sucralfate is a safe, cheap and active drug for the prevention and treatment of radiation mucositis especially in patients with pelvic irradiation.

Head and Neck Neoplasms↗
PubMed1997

The crystallization kinetics of sodalites grown by the hydrothermal transformation of kaolinite studied by 29Si MAS NMR.

The hydrothermal transformation of kaolinite to basic sodalite Na8[AlSiO4]6 (OH.H2O)2 and hydroxoborate sodalite Na8[AlSiO4]6 [B(OH)4]2 has been investigated at different temperatures (353 and 473 K). In the early stage of the reactions, the crystallization kinetics was studied by X-ray powder diffraction, thermogravimetry, IR spectroscopy and 29Si MAS NMR spectroscopy. Besides the crystallization of the sodalites, no further intermediate phases were formed. MAS NMR of the 29Si nucleus has been found to be a versatile tool to follow the progress of reactions from the signal ratio of the initial material and the crystallization product because the differences in chemical shifts result in well-separated signals. From these measurements, the growth rates of the sodalites could be determined quantitatively even for the very early stages of crystallization. It was found that sodium carbonate impurities in the NaOH solution used for the synthesis has an important influence on the reaction kinetics.

Crystallization↗
PubMed1997

Early reduction of the challenge recovery rate following immunization with irradiated infective larvae in a filaria mouse system.

The filaria Litomosoides sigmodontis, which develops a patent infection in BALB/c mice, was used to determine the fate of a challenge inoculum following immunization of mice with irradiation attenuated infective larvae (3 subcutaneous inoculations at weekly intervals with 25 L3 irradiated at 60 krad, and challenge with 25 L3 two weeks after the final immunization). The adult worm burden of vaccinated mice was reduced to 50% of that of controls although the pattern of larval migration and microfilaraemia were not affected. Necropsies showed that the increased killing of the filariae of the challenge inoculum occurred at the L3 stage within the first 2 days of challenge. This result draws attention on the protective mechanisms operating very early and probably in the subcutaneous region.

Animals↗
PubMed1997

Paclitaxel in simultaneous radiochemotherapy of head and neck cancer: preclinical and clinical results.

Several studies have presented evidence that paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) displays a radiation-sensitizing effect. We therefore analyzed the influence of paclitaxel and concomitant radiation on the proliferation kinetics of head and neck tumor cells and normal fibroblasts. Our data clearly support the notion that paclitaxel given with radiation exerts an additive effect on the clonogenic survival of squamous cell carcinoma cells and normal fibroblasts. Since concomitant radiochemotherapy has proven to be beneficial for the treatment of locally advanced head and neck cancer, we are testing the feasibility of simultaneous paclitaxel plus radiotherapy. Paclitaxel is given on a one-time weekly basis. Up to now, 13 evaluable patients have been treated, and the maximum tolerable dose has not been reached at 40 mg/m2. Mucositis is expected to be the dose-limiting toxicity.

Adult↗
PubMed1997

Progressive hydrocephalus in two members of a family with autosomal dominant Noonan phenotype.

We present a family with an autosomal dominant phenotype characterized by pulmonary valve stenosis, craniofacial dysplasia with marked hypertelorism and, as a variable feature, progressive hydrocephalus. This phenotype is manifested in four patients from three subsequent generations of a family, with expression ranging from mild pulmonary stenosis combined with slight but characteristic facial dysmorphism to severe cyanotic pulmonary valve stenosis with multiple malformations lethal in early childhood. We consider this to be an unusual variant of Noonan syndrome.

Adult↗
PubMed1997

[Rehabilitation of patients with alcoholic liver cirrhosis after orthotopic liver transplantation: a 7-year follow-up].

Alcoholic liver cirrhosis is the main indication for orthotopic liver transplantation. Since 1988, 52 patients with alcoholic liver cirrhosis have been transplanted at the Department of Surgery of the University of Heidelberg. The survival rates are as follows: 73% of the patients survived for 1 year, 68% for 2 and 3 years, 64% for 4 years, and 57% survived for 5 years. After transplantation, recidivism occurred in 6 patients. Remarkable in this case was the fact that all 6 patients had a relatively short period of abstention prior to surgery (2 to 5 months). In 12 patients, a small carcinoma was found in the cirrhotic liver. This had neither been seen previously by ultrasound nor by computer tomography. In summary, orthotopic liver transplantation is an excellent mode of treatment in end-stage alcoholic liver cirrhosis. However, the patients have to be carefully selected in order to avoid recidivism following transplantation.

Adult↗
PubMed1996

Earth-Based Observations of the Galileo Probe Entry Site

Earth-based observations of Jupiter indicate that the Galileo probe probably entered Jupiter's atmosphere just inside a region that has less cloud cover and drier conditions than more than 99 percent of the rest of the planet. The visual appearance of the clouds at the site was generally dark at longer wavelengths. The tropospheric and stratospheric temperature fields have a strong longitudinal wave structure that is expected to manifest itself in the vertical temperature profile.

Journal Article↗