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Biomedical subjects

E Geyer

Publications and source records attributed to E Geyer.

At least 19 recordsLinked to original sources
PubMed2001

Experience with split-course external beam irradiation +/- chemotherapy and integrated Ir-192 high-dose-rate brachytherapy in the treatment of primary carcinomas of the anal canal.

PURPOSE: The effect of the treatment of anal cancer by performing a high-dose-rate (HDR) brachytherapy boost during a short split between the external beam radiotherapy series (EBR) +/- chemotherapy was investigated. METHODS AND MATERIALS: Thirty-nine patients with anal canal cancers, stages T1-T4 N0-2 M0, were treated with split-course EBR (50-50.4 Gy) and a Iridium 192 ((192)Ir-) HDR boost (6 Gy) performed during the 1-2-week split. Patients who failed to achieve a complete tumor response received additional brachytherapy. Chemotherapy with 5-fluorouracil and mitomycin C was offered to patients with tumors > 3 cm and employed concomitantly on days 1-5 and day 1, respectively, of each EBR series. RESULTS: Follow-up ranged from 3 to 140 months (median 31). Median treatment duration was 56 days. The 3-year (5-year) actuarial rates of locoregional control (LRC) and disease-specific survival (DSS) were 81% (76%) and 80% (76%), respectively. The crude rate of anal preservation was 77% overall, and 97% in patients in whom LRC was achieved. Uncompromised anal function was recorded in 93% of these patients. The actuarial 3-year (5-year) rate of colostomy-free survival (CFS) was 78% (73%). There was a statistically significant difference in LRC and DSS according to stage, tumor size, and nodal status. Complications requiring surgical intervention occurred in 7.6% of patients. CONCLUSION: The integration of the HDR boost in a split-course EBR regimen +/- chemotherapy resulted in excellent sphincter function without an increase of severe complications and with rates of LRC, DSS, and CFS, which compare favorably with those reported in the literature.

Adult↗
PubMed1997

Endocavitary Ir-192 radiation and laser treatment for palliation of obstructive rectal cancer.

Endoscopic laser therapy (ELT) either alone or combined with endocavitary Ir-192 radiation is performed for advanced, inoperable rectal cancer and when patients are ineligible for surgery due to severe concomitant medical illness. During the period from January 1984 to January 1997 we treated 81 patients (51 males, 30 females). Sixty-seven patients had ELT only using a ND-Yag Laser system. Twenty-five patients (average age: 80.5 years) were ineligible for surgery (Group I). Forty-two patients (74.1 years) had an advanced locally inoperable tumour (Group II). Fourteen patients (76.5 years) underwent a combined therapeutic regime with endocavitary Ir-192 afterloading following ELT (Group III). Adequate desobliteration was achieved in 100% (groups I and III) and 97% (group II) of the patients. The average interval to aftertreatment was 8.4 weeks in group I and 9.4 weeks in group II, compared to 11.5 weeks in group III. Serious complications (perianal abscess, rectovaginal fistula) occurred in 3.7%, minor complications (laser-induced bleedings, unclear fever) in 12.3%. All laser-induced bleedings could be dealt with using laser therapy. The frequency of treatment was governed by tumour mass and the patient's survival. The results suggest that additional endocavitary radiation significantly prolongs the maintenance of normal bowel function compared with laser therapy alone.

Aged↗
PubMed1996

Neutral glycolipids of Schistosoma mansoni as feasible antigens in the detection of schistosomiasis.

The neutral glycolipid fraction from mouse-propagated, Schistosoma mansoni adult worms has been investigated as to its chromatographic and antigenic properties, and whether it fulfills the serodiagnostic antigen requirements of sensitivity and specificity in the detection of schistosomiasis. Serological analyses were performed by thin-layer chromatography immunostaining and ELISA. In the acute-phase form of mouse schistosomiasis, the kinetics of development of neutral glycolipid-specific antibody levels was correlated with the intensity of the initial infection and the response was dominated by IgG, as represented by the subclass IgG1. With the experimental animal helminthiases screened, glycolipid antigenicity fulfilled the fundamental traits for a serodiagnostic reagent. In the chronic-phase form of human schistosomiasis mansoni, neutral glycolipid-specific antibody levels were not correlated with the intensity of infection, as estimated from the faecal content of parasite eggs, whilst the isotypic response was dominated by IgM and IgG, the latter represented primarily by IgG1 and secondarily by IgG3. With other human helminthiases, glycolipid antigenicity was incomplete, in that, the specificity was only partially fulfilled. The reason for this incomplete specificity has been clarified, in part, by the detection of cryptic schistosomiasis infections in the cohorts of African patient sera examined.

Animals↗
PubMed1996

Intraoperative radiation therapy, endotracheal hyperthermia and IR-192-brachytherapy in patients with advanced thyroid cancer.

Tracheal stenosis due to infiltrative nonresectable thyroid cancer causes severe reduction in life quality. Palliative therapy, apart from tracheostomy is--up to now--intraluminal and/or external radiation. Good tumor control is achieved by local hyperthermia. A combined modality treatment (CMT) consisting of surgery, brachytherapy and intraoperative radiation, eventually combined with intraluminal NdYg-Laser-desobliteration was performed. An intraoperative radiation therapy (IORT)-protocol was designed for poorly differentiated non-anaplastic thyroid carcinoma. Out of 155 cases of differentiated thyroid tumors, 12 showed marked vascular and/or capsular invasion. Five entered the study (3 primarily local invasive tumors, 2 local recurring). IORT was administered after tumor surgery (4-10 Gy) and combined with postoperative percutaneous irradiation. The tumor control rate in the thyroid bed is 5/5, 1/5 developed mediastinal nodes, 1/5 with primary mediastinal tumor extend shows tumor progression. No specific complications occurred.

Adenocarcinoma, Follicular↗
PubMed1995

Bovine cysticercosis: demonstration in experimentally infected calves of serum IgG antibodies reactive with neutral glycolipids of Taenia saginata and T. crassiceps metacestodes.

The immunoreactivity of Taenia saginata and T. crassiceps metacestode neutral glyco(sphingo)lipids towards IgG antibodies derived from the sera of calves with experimental cysticercosis has been established. The glyco(sphingo)lipids are separable by normal-phase HPTLC (high-performance thin-layer chromatography) into groups of increasing sugar-chain length (lipid/ceramide mono-, di-, tri-, tetra- and > tetrasaccharides), with those corresponding to three and four hexoses being the main immunoreactive components (HPTLC immunostaining). In ELISA (enzyme-linked immunosorbent assay), reverse-phase HPTLC-isolated T. crassiceps metacestode glyco(sphingo)lipids equivalent to tri- and tetrahexoside allowed a discrimination between non-infected and infected calves (at least 80 metacestodes recovered). The formation of IgG antibodies was correlated with the infection, not with other non-specific inducing factors, as seen by the differential humoral response detected in experimentally infected (T. saginata) calves before and after Praziquantel treatment (HPTLC immunostaining and ELISA).

Animals↗
PubMed1995

Intraoperative radiation therapy in advanced thyroid cancer.

An intraoperative radiation therapy (IORT)-protocol was designed for poorly differentiated non-anaplastic thyroid carcinoma. Out of 155 cases of differentiated thyroid tumours, 12 showed marked vascular/capsular invasion. Five entered the study (three primarily local invasive tumours, two local recurring). IORT was administered after tumour surgery (4-10 GY) and combined with post-operative percutaneous irradiation. The tumour control rate in the thyroid bed was achieved in all five patients, 1/5 developed mediastinal nodes and 1/5 with primary mediastinal tumour extension showed tumour progression. No specific complications occurred.

Adenocarcinoma, Follicular↗
PubMed1995

Initiation of chemical studies on the immunoreactive glycolipids of adult Ascaris suum.

There is a general lack of basic information concerning one class of glycoconjugate, the glycolipids, from parasitic nematodes. As the prototype, the neutral glycolipid fraction derived from adult males of Ascaris suum was investigated as to its chromatographic, differential chemical staining, antigenic and chemical properties. The thin-layer chromatography-resolved neutral fraction glycolipids could be classified into components of fast and slow migrating band groups. Immunoreactivity was restricted to the latter as detected by IgG and IgM anti-neutral fraction glycolipid antibody levels in serial infection sera of mice. Similarities of chromatography, antigenicity and serological cross-reactivity have been extended to the neutral glycolipid fractions of other parasitic nematodes: Litomosoides carinii and Nippostrongylus brasiliensis. Chemical, differential chemical staining and enzymatic analyses identified the Ascaris suum antigenic, slow migrating band group of components as amphoteric glycosphingolipids, and not the originally hypothesized glycoglycerolipids or glycosylphosphatidylinositols, that contained typical neutral monosaccharide constituents and a zwitterionic phosphodiester linkage, most probably phosphocholine. Glycosphingolipid-immunoreactivity is eliminated on cleavage of the zwitterionic phosphodiester linkage by hydrofluoric acid treatment.

Animals↗
PubMed1994

Interstitial hyperthermia and high dose rate brachytherapy in the treatment of anal cancer: a phase I/II study.

PURPOSE: The rate of local failure is sufficiently high following sphincter conserving surgery and radiation therapy for advanced anal cancers to warrant investigation of improved local treatment techniques. This Phase I/II study was undertaken to investigate the site-specific toxicities and response of Stage II and III anal cancers to interstitial thermoradiotherapy using a hot water interstitial system. METHODS AND MATERIALS: Between September 1988 and March 1991, 14 patients with primary carcinomas of the anal canal, UICC Stage T2-3, N0-1, M0, were treated with split-course external beam irradiation to the pelvis (30 Gy + 20 Gy) and 1 or 2 interstitial Iridium-192 high dose rate (Ir-192 HDR) implants (6-8 Gy each) immediately followed by interstitial hyperthermia (HT). Patients with tumor diameters > 3 cm were scheduled to receive chemotherapy consisting of 2 courses of 5-fluorouracil and mitomycin C given concomitantly with external beam radiation. Interstitial hyperthermia was induced by circulating warm water through the needles that were implanted to hold the Ir-192 source. The treatment goal was to achieve and maintain a temperature of 42.5 degrees C over a time period of 40 min. A 3-point thermocouple probe inserted into one or two additional needles was used for thermometry. The temperatures were recorded by manual mapping along these needles at steps of 0.5 or 1 cm. RESULTS: A total of 20 Ir-192 HDR-HT implants were performed in 14 patients. All but two patients completed the external beam irradiation; five patients received concomitant chemotherapy. Analysis of thermal parameters showed that minimum intratumoral temperatures (Tmin) of 42 degrees C, 42.5 degrees C, 43 degrees C, and 44 degrees C were achieved in 64%, 37.5%, 14%, and 7% of patients, respectively. Intratumoral mean Tmin, mean average, and mean maximum temperatures for these patients were 41.7 degrees C, 42.4 degrees C, and 43.4 degrees C, respectively. Brachytherapy and HT were well tolerated. Clinical complete responses (cCR) were obtained in 11/14 (78.5%) patients, complete histopathological responses (pCR) in 10/14 (71%). Only one patient with pCR recurred and succumbed to her disease. Patients with persistent disease (1 minimal and 3 partial responders, including 1 cCR) underwent abdominal-perineal resection but subsequently died from local-regional recurrence. One patient with pCR died from unrelated causes. Median survival for all patients from onset of radiation to death or last follow-up is 26 months. Eight patients are alive disease-free after a follow-up ranging from 16-44 months (median: 30, mean: 30 months). Treatment complications were limited to two patients who developed persistent ulcers. Sphincter function was maintained in 50% of patients. CONCLUSION: This study demonstrates that interstitial warm water hyperthermia in combination with brachytherapy for anal carcinomas is feasible and did not add to complications when compared to studies employing external beam irradiation and brachytherapy alone. The thermal parameters obtained by the warm water system compare favorably to those reported by others using radiofrequency and microwave systems.

Adult↗
PubMed1994

Evaluating intraoperative radiation therapy (IORT) and external beam radiation therapy (EBRT) in non-small cell lung cancer (NSCLC). Five years experience.

A pilot study on intraoperative radiation therapy (IORT) combined with external beam radiation therapy (EBRT) in nonresectable non-small cell lung cancer (NSCLC) was performed in 31 patients (mean age: 66.2 years, range: 51-80; 10 anatomically and functionally, 21 functionally, nonresectable; 20 squamous-cell, 11 adenocarcinoma). The tumor was exposed by lateral thoracotomy and a staging lymph node dissection was performed (final staging 7 T1, 16 T2, 8 T3; 11 nodal positive). Ten to 20 Gy IORT (energy: 7-20 MeV electrons) were delivered to the tumor. Unilateral continuous positive airway pressure ventilation of the diseased lung was used to reduce the amount of healthy lung tissue in the IORT port and to minimize the ventilatory movement. Secondary collimation and direct shielding of radio-sensitive structures within the IORT port by aluminium sheets were used to further reduce collateral damage. Four weeks after IORT, 46 Gy EBRT (2 Gy/day 5 times a week; 8-23 MeV photons) were administered to the mediastinum and to the tumor-bearing area on an outpatient basis. In nodal positive cases the mediastinal dose was increased to 56 Gy. Twenty-three patients were evaluable. In 13 complete, in 8 partial (50-97% regression) and in 2 minor response has been achieved. Five patients experienced a recurrence (local only: 2; local and distant: 1; distant only: 2). Twelve patients died of underlying cardio-respiratory disorders within 6 to 25 months after IORT; 7 died of cancer. The overall 5-year survival rate including the incidental deaths is 14.7%. The recurrence-free survival rate is 53.2%.

Adenocarcinoma↗
PubMed1994

Litomosoides carinii: macrofilariae-derived glycolipids--chromatography, serology and potential in the evaluation of anthelminthic efficacy.

A preliminary characterization of the glycolipids of Litomosoides carinii macrofilariae, resolved according to their chromatographic, chemical and serological properties, has been performed. Emphasis has been placed on the neutral fraction glycolipids. These are separable on thinlayer chromatography into two groups of fast and slow migrating band components, that differ in their migration, differential chemical staining and serological traits, respectively. Serological analyses have been accomplished by thin-layer chromatography immunostaining and ELISA. Only components of the slow migrating band group react with infection serum from Litomosoides carinii-infected Mastomys coucha. Cross-reactivity experiments with homologous and heterologous infection sera of various helminthiases indicate that, epitopes bound to the neutral glycolipid fraction show structural similarity within the Nematoda, but not to the Cestoda or Trematoda. The dynamic development of specific Ig-, IgG- and IgM-anti-neutral glycolipid fraction antibody levels were correlated with the different progression of L. carinii and Brugia malayi infections in the multimammate rat, Mastomys coucha. The reduction in the dynamics of IgG- and IgM-antibody levels on chemotherapeutic treatment with the filaricides flubendazole and CGP 20376 has been related to their macrofilaricide-activity.

Animals↗
PubMed1994

Preparation and sequence analysis of Taenia crassiceps metacestode recombinant antigens with potential for specific immunodiagnosis of human cerebral cysticercosis.

A Taenia crassiceps metacestode cDNA expression library in lambda gt 11 was screened with rabbit antisera to metacestodal T. solium and T. saginata crude extract. Primary clones (121) were identified, and after rescreening and lysogenization in Escherichia coli Y 1089, were tested in Western blot for reactivity with the same antisera. In addition, analyses were performed with rabbit antisera directed towards T. crassiceps and Echinococcus granulosus metacestode crude extract, sera from humans with neurocysticercosis (Mexico) and other important helminth diseases, mice and calves with experimental T. crassiceps and T. saginata infections and normal sera. Of those tested, 22 clones expressing beta-galactosidase fusion proteins (approximately 118-132 kDa) were reactive with IgG antibodies of cysticercotic patients and T. crassiceps infected mice. Of these clones, 11 were also sero-positive with calf-IgG antibodies against T. saginata larvae. None of the 22 clones reacted with IgG antibodies due to human cystic and alveolar echinococcosis, intestinal/hepatic or urinary schistosomiasis, African onchocerciasis or with sera from uninfected controls (man, rabbit, calf and mouse). Of these 22 clones, 15 have been subcloned into the plasmid vectors pGEX-2T (modified) and pT7T3 alpha 19. Expressed glutathione-S-transferase fusion proteins were again tested for sensitivity and specificity by Western blot, and concentrated by affinity chromatography. The nucleotide sequence of the cDNA inserts of 9 clones has been determined in pT7T3 alpha 19 and revealed identity in 4 and 5 clones, respectively.

Amino Acid Sequence↗
PubMed1993

Chromatographic and antigenic properties of Echinococcus granulosus hydatid cyst-derived glycolipids.

The neutral and acidic fraction glycolipids of Echinococcus granulosus metacestode tissue compartments were isolated, defined by their chromatographic and antigenic properties, and assessed as to their efficacy as antigens in the serodiagnosis of human hepatic cystic and alveolar echinococcosis, and other helminthiases. Analyses were accomplished by thin-layer chromatography immunostaining and ELISA. The neutral glycolipid fraction's major carbohydrate epitope was the same as or very similar to that of Taenia crassiceps neutral glyco(sphingo)lipids, as represented by the 'neogala'-series core structure. The blood group-active, carbohydrate epitope P1 was expressed by a number of neutral fraction glycolipid component bands. The reverse-phase, thin-layer chromatography-isolated neutral fraction glycolipid component, designated Ag1, was efficient in the serological discrimination of cystic echinococcosis medium to high-titred sera. Ag1 did not specifically discriminate low-titred sera, i.e., other human helminthiases. The detected sialic acid residues of the acidic fraction glycolipids, on enzymatic cleavage, were identified as N-acylneuraminic acid and terminal. The acidic fraction glycolipids exhibited the paradox of only chemically minor components being antigenic towards cystic and alveolar echinococcosis infection sera. The combined acidic fraction glycolipid components Ra and Rx were capable of serological discrimination between cystic echinococcosis, alveolar echinococcosis and other helminthiases.

Animals↗
PubMed1992

Glycosphingolipids in cestodes. Chemical structures of ceramide monosaccharide, disaccharide, trisaccharide and tetrasaccharide from metacestodes of the fox tapeworm, Taenia crassiceps (Cestoda: Cyclophyllidea).

The presence of glycosphingolipids in the metacestodes of the fox tapeworm, Taenia crassiceps, has been established. The normal-phase TLC pattern of the neutral-fraction glycolipids revealed groups of bands corresponding to homologous components of increasing sugar chain length. The three simplest glycolipid components have been isolated and their chemical constitution determined as being of the neogala series: Gal beta 1Cer, Gal beta 6Gal beta 1Cer and Gal beta 6Gal beta 6Gal beta 1Cer. The ceramide tetrasaccharide fraction has been found to consist of a mixture of neogalatetraosylceramide, as an elongation of the neogala series, Gal beta 6Gal beta 6Gal beta 6Gal beta 1Cer and the component Gal alpha 4Gal beta 6Gal beta 6Gal beta 1Cer (both occurring in approximately equimolar proportions). The long-chain bases of the ceramide monogalactoside, digalactoside, trigalactoside and tetragalactosides contain, as well as small amounts of sphingosine, predominantly dihydrosphingosine/phytosphingosine in the approximate ratios 1.7:1, 1.4:1, 1:1 and 2.3:1, respectively. The major ceramide fatty acids have particularly long chains, with hexacosanoic and octacosanoic acids predominating. Upon reverse-phase TCL, the glycolipid components ceramide monogalactoside, digalactoside and trigalactoside were each separable into five component bands. Parent glycolipid components therefore show component band distributions comparable to one another in being governed by similar ceramide constitutions.

Animals↗
PubMed1992

Comparative serological reactivity of Taenia crassiceps, Taenia solium and Taenia saginata metacestode neutral glycolipids to infection serum from Taenia crassiceps-infected mice.

A comparative survey was undertaken of the neutral fraction glycolipids from the metacestodes of 3 taeniid species, Taenia crassiceps, Taenia solium and Taenia saginata, to determine their chemical and serological staining patterns on separation by thin-layer chromatography. The orcinol-positive patterns of T. solium and T. saginata metacestodes exhibited a closer superficial resemblance to each other than to T. crassiceps or T. saginata adults. A comparison of component migration properties against standards of known structure indicated the main oligosaccharide chains to be mono-, di-, tri- and tetrasaccharides; however, in T. solium this was extended to at least a heptasaccharide. The multiple banding characteristic of each component is a consequence of lipid moiety heterogeneity. Serologically, the patterns of the 3 taeniid species neutral fraction glycolipids showed virtually the same immunological reactivity towards mouse normal serum, infection serum and a monospecific, polyclonal antibody directed against the trisaccharide component of T. crassiceps. The latter antibody was isolated from mouse infection serum by affinity chromatography on a column of glycolipid-bound octyl-Sepharose CL-4B. Immunochemically, the major common epitope expressed by the neutral fraction glycolipids of the 3 taeniid species is the same or very similar to the glycosphingolipid, neogalatriaosyl ceramide derived from the marine mollusc Turbo cornutus (Gal(beta 1-6) Gal(beta 1-6) Gal(beta 1-1)Cer). Host tissue neutral fraction glycolipids, porcine muscle and bovine muscle, as well as human spleen, were not immunoreactive.

Animals↗
PubMed1991

Immunological recognition of larval Taenia crassiceps glycolipids by sera from parasite-infected mice.

The isolation and purification of a neutral glycolipid fraction from Taenia crassiceps metacestodes (KBS strain), harvested from both male and female NMRI mice at 70-80 days following intraperitoneal infection, revealed 24 thin-layer chromatography-designated glycolipid bands. The glycolipids were defined as ceramide mono- (n = 3), di- (n = 3), tri- (n = 4), tetra- (n = 5), and greater than tetrasaccharides (n = 9) according to their running properties as defined by thin-layer chromatography against standards of known structure. The defined glycolipids were tested for immunoreactivity with sera from noninfected and T. crassiceps-infected NMRI mice (intraperitoneal injection or implantation of 15 larvae/animal) using the enzyme-linked immunosorbent assay (ELISA) until day 33 p.i. (IgM and IgG reaction) and high-performance thin-layer chromatography (HPTLC) combined with immunostaining (IgG reaction) until day 7 p.i. ELISA-determined IgM and IgG titres were significantly elevated from day 5 p.i. Immunostaining revealed early reactivity for certain ceramide tetra- and greater than tetrasaccharides (n = 6) on day 3 p.i. From day 5 p.i. onwards, nearly all glycolipids, including ceramide mono- and disaccharides, were recognized by the sera from metacestode-challenged mice. On day 7 p.i., a total of 22 bands were serologically active; of these, a considerable number (n = 10) showed increased staining intensity. Remarkably, in many cases (10 of 20), 3 glycolipids (tetra- and greater than tetrasaccharides) were weakly recognized by mouse sera taken before infection.

Animals↗