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Biomedical subjects

G Ehlers

Publications and source records attributed to G Ehlers.

At least 19 recordsLinked to original sources
PubMed2006

Neutron spin-echo investigation of slow spin dynamics in kagomé-bilayer frustrated magnets as evidence for phonon assisted relaxation in SrCr9xGa12-9xO19.

A neutron spin-echo investigation of the low temperature spin dynamics in two well-characterized kagomé bilayer compounds SrCr9xGa12-9xO19 (x=0.95, SCGO) and Ba2Sn2ZnCr7xGa10-7xO22 (x=0.97, BSZCGO) reveals two novel features. One is the slowing down of the relaxation rate without critical behavior at Tg, where a macroscopic spin-glass-like freezing occurs. The second is, in SCGO at 4 K (approximately Tg)<T<7 K, the relaxation rate activation energy Ea=7+/-0.4 meV, equal to the energy of a phonon mode, pointing out the role of spin-lattice coupling.

Journal Article↗
PubMed2004

Dynamic properties of a diluted pyrochlore cooperative paramagnet (Tb(p)Y(1-p))2Ti2O7.

Investigations of the spin dynamics of the geometrically frustrated pyrochlore (Tb(p)Y(1-p))2Ti2O7, using muon spin relaxation and neutron spin echo, as a function of magnetic coverage p, have been carried out. Our major finding is that paramagnetic fluctuations prevail as T-->0 for all values of p, and that they are sensitive to dilution, indicating a cooperative spin motion. However, the percolation threshold pc is not a critical point for the fluctuations. We also find that the low temperature spectral density has a 1/f behavior, and that dilution slows down the spin fluctuations.

Journal Article↗
PubMed2000

Observation of two time scales in the ferromagnetic manganite La1-xCaxMnO3, x approximately 0.3.

We report new zero-field muon spin relaxation and neutron spin echo measurements in ferromagnetic (FM) (La,Ca)MnO3 which suggest at least two spatially separated regions possessing very different Mn-ion spin dynamics. One region displays diffusive relaxation, "critical slowing down" near T(C) and an increasing volume fraction below T(C), suggesting overdamped FM spin waves below T(C). The second region possesses more slowly fluctuating spins, a linewidth independent of q, and a decreasing volume fraction below T(C). The estimated length scale for the inhomogeneity is <or=30 A.

Journal Article↗
PubMed1991

Long-term therapy of HIV-associated Kaposi's sarcoma with recombinant interferon alpha-2a.

Five young male patients with HIV-associated Kaposi's sarcoma (KS) were treated with recombinant interferon alpha 2a (rIFN-alpha-2a) over a period of 2-2.5 years. An IFN dose of 18 x 10(6) IU was given subcutaneously every day during the first 3 months of treatment and then on alternate days. Additional treatment with radiotherapy and laser therapy was given and, in some cases, isolated skin nodules were excised. Within 7 months of initiation of therapy one patient had a complete remission of his tumours, however, tumour progression recurred after the patient discontinued treatment. In another patient the tumour cleared within 9 months of rIFN therapy, and after 52 months he is still free of KS. The condition of a third patient tended to become stabilized during the first 6 months of therapy, but after 60 months there has been a slow progression. The fourth and fifth patients died 25 and 28 months, respectively, after the histological diagnosis of KS and the initiation of treatment. While on therapy with rIFN-alpha-2a, no life-threatening opportunistic infections occurred. The side-effects were mostly well tolerated, and no severe changes in haematological parameters were caused by the therapy.

Adult↗
PubMed1991

Incidence and mortality of malignant melanoma in Berlin (West) from 1980 to 1986.

Newly diagnosed melanomas were investigated utilizing the histological reports from the 4 Departments of dermatology as well as from 3 Departments of pathology in Berlin (West) during the years 1980-86. The study included 960 melanomas and documented the histological features, age, gender and nationality of the patients involved. 936 patients were Germans (379 males, 557 females), and the mean age-adjusted incidence rate (for the European standard population) was 7.1 cases per 100,000 inhabitants and year for both genders with an increase between 1980-81 and 1985-86 in men from 6.0 to 9.8 and in women from 5.8 to 7.8/100,000 and year. Thus a 49% increase in incidence was observed for both genders combined during a 5-year period. In this study, a preponderance of male incidence rates was observed for the first time in Germany. Interestingly, the age-adjusted incidence rate for the Turkish population, which is the largest foreign population with more than 100,000 inhabitants in Berlin, was only 1.3/100,000 and year. 162 men and 145 women died of melanoma in the time period examined. From 1980-81 to 1985-86, the age-adjusted mortality rate changed from 3.5 to 2.6 for men and from 1.2 to 1.6 for women per 100,000 and year, thus revealing a slight decrease in mortality for both genders combined.

Adult↗
PubMed1991

[Chronic erosive, therapy-resistant perianal herpes (type II) with herpes proctitis in AIDS].

In an AIDS patient who had repeated successful treatment with acyclovir in his history, erosive herpes perianalis with herpes proctitis appeared, which persisted over several weeks. High-dose intravenous administration on of acyclovir (500-750 mg, 3 x daily, over 7 weeks) did not reveal any beneficial effects: However, almost complete clearing of the lesions occurred within 3 weeks of intravenous administration of Foscarnet (50 mg/kg body wt., 3 x daily). No relapse was seen in a follow-up period of 4 months. HSV type II was isolated by culture from the erosive lesions before treatment, but no virus was found 1 week after application of Foscarnet. The unusual chronic refractory course of a severe HSV type II infection in AIDS suggests the presence of an acyclovir-resistant HSV strain in this case. This is the first observation indicating acyclovir-resistance in the Federal Republic of Germany and a warning against the unlimited use of acyclovir in AIDS patients. Foscarnet may be beneficial in some of these cases.

Acquired Immunodeficiency Syndrome↗
PubMed1989

[Buschke-Ollendorff syndrome].

Buschke-Ollendorff syndrome means the coincidence of dermatofibrosis lenticularis disseminata and focal sclerotic bone dysplasia (osteopoikilosis). Referring to the case of a 5-year-old patient, we give as survey of this disease.

Collagen↗
PubMed1988

[Acute primary phase as an indicator of HIV-1 infection. The general symptoms and polymorphic exanthema with mouth mucosal involvement 2 to 6 weeks before seroconversion].

The initial symptoms of an HIV-1 infection were observed in four patients. The following were characteristic for the acute primary phase: (a) initial maculopapular exanthema, especially of the trunk, with occasional transition into a papulovesical appearance; (b) involvement of the oral mucosa, often of aphthous character; and (c) general malaise with fever and lymphadenopathy. The observed cutaneous changes had, on one hand, features of a Coxsackie or mononucleosis exanthema, on the other of secondary syphilis. In three patients seroconversion occurred within 2-6 weeks, the fourth failed to return for follow-up. The listed acute primary symptoms can be used as the earliest indicators of an HIV-1 infection having occurred.

Acquired Immunodeficiency Syndrome↗
PubMed1988

[Congenital telangiectatic erythema (Bloom syndrome)].

"Congenital telangiectatic erythema" (Bloom's syndrome) is very rare; it is linked to a group of hereditary diseases and a common feature is cellular hypersensitivity to a variety of physical or chemical agents. The mode of transmission is autosomal-recessive. Characteristic criteria for Bloom syndrome are: consanguinity of the parents; androtropia; low birth weight, short stature (proportional); and persistent telangiectatic erythema in sun-exposed areas, sometimes with blistering. The syndrome is also associated with a facultative lack of antibodies. Of great importance is the high leukaemia morbidity among individuals with this syndrome; chromosomal aberrations and breakages play a significant role. Histological changes comprise an increase in dilated vessels in the upper dermis and damage and loss of elastic fibers. We give a review of Bloom's syndrome and present a case report.

Bloom Syndrome↗
PubMed1987

[Disseminated mucocutaneous Kaposi sarcoma in AIDS. Clinical and therapeutic experiences in 13 patients].

Since 1980 a new epidemic form of disseminated mucocutaneous Kaposi's sarcoma (KS) with a progressive clinical course has been observed in populations at risk. Since 1982, 13 cases of AIDS-associated KS have been seen in our department; all of them were in young homosexual males with circulating HIV antibodies and a reduction in the ratio of T-helper to T-suppressor lymphocytes (0.05-1.3). Following systemic treatment with recombinant alpha A-interferon (rIFN-alpha A) over a period of 6 months (18 million IU/day for 3 months; later 18 million IU/3 X weekly) together with other concomitant measures (superficial X-ray radiation, argon laser radiation, surgical excision of isolated lesions) we registered complete remission of the remaining lesions in 2 cases, progression of the disease in 4 cases, and at least temporary stabilization of the disease in 7 cases. In 4 patients opportunistic infections occurred during rIFN treatment: Pneumocystis carinii pneumonia (PCP) with lethal outcome in 2 cases, atypical mycobacteriosis in 2 cases, and Legionella pneumoniae infection in 1 case. Two additional deaths were registered due to PCP appearing during the post-treatment period. Life-threatening virus infections were not observed during rIFN treatment. Out of 9 patients receiving prophylactic trimethoprim/sulfamethoxazole medication, only 1 developed allergic exanthema as a result of this drug combination. Occasionally, rIFN-induced leukopenia was seen and pronounced thrombocytopenia appeared in 1 patient during treatment. Overall, systemic rIFN therapy was well tolerated; its long-term administration in patients with AIDS-associated mucocutaneous KS seems to be well justified according to these preliminary observations.(ABSTRACT TRUNCATED AT 250 WORDS)

Acquired Immunodeficiency Syndrome↗
PubMed1986

HLA-B 16 in Hailey-Hailey's disease.

Hailey-Hailey's disease is an autosomal hereditary disease of the skin for which only few data exist in regard to genetic markers concerning the HLA system. We report on HLA-A, B and C typing results finding an increased frequency of 55.5% HLA-B 16 positive patients compared to 8.2% in healthy controls.

Adolescent↗
PubMed1985

Scattered radiation doses to some critical organs during pediatric radiotherapy.

The levels of scattered radiation doses imparted to the eyes, thyroid and gonads of pediatric patients treated with orthovoltage radiation (300 kVp, 2.0 mmCu HVL) and with a 4-MV linear accelerator, were determined by making thermoluminescent dosimeter (TLD) measurements in three paraffin phantoms of different sizes. These phantoms were made from molds of mannequins used for store display, of approximate heights 30", 40" and 50", representing children of ages 1-2, 4-5 and 8-10 yr, respectively. The sites chosen for irradiation were (1) the whole brain, (2) the chest, (3) the kidney bed, (4) the whole abdomen and (5) the spinal column. These sites are normally treated in such pediatric malignancies as medulloblastoma, neuroblastoma and Wilms' tumor. Some of the doses measured are less than 10 rad for an entire treatment regimen, and would therefore be categorized as low-level doses. Where radiation was the only mode of treatment for long-term survivors of such malignancies, especially those treated 20-30 yr ago with orthovoltage radiation, useful data may be extracted for contributing to our knowledge about the long-term effects of low levels of radiation.

Cerebellar Neoplasms↗
PubMed1983

[Chronic urticaria in the dermatology clinic].

In order to clarify the genesis of different forms of urticaria, particular experiences of the Practicing dermatologist are required regarding allergology as well as the equipment of his practice which is of considerable importance. Certain examination methods should, however, be carried out under clinical conditions, as far as special technical instruments, comparison and reproduction of results and allergy exposition are concerned. Special regard has to be paid to the phenomenon of intolerance. Corresponding reactions are being dealt with increasingly. Even clinical treatment only produced few discoveries of allergens. Therefore, steps have to be taken to set up more effective examination techniques.

Allergens↗
PubMed1982

Radiotherapy of regional epidermoid carcinoma of the lung: a study in fractionation.

This paper reports a prospective randomized multicenter trial of two fractionation schemes in the supervoltage radiotherapy of locally inoperable epidermoid lung cancer. This study was stimulated by the need to provide improved and more acceptable treatment methods for patients with this condition, the most common cell type of lung cancer. The majority of such patients are not suitable for resection because of metastasis or because of extensive local disease, even though exploratory thoracotomy may be performed. It was therefore considered important to identify preferred methods of irradiation in this situation which is found in a large proportion of patients with lung cancer.

Adult↗
PubMed1979

Congenital factor VII deficiency. A report of four new cases.

Four new cases with congenital homozygous factor VII deficiency are described. Factor VII levels were reduced to less than 1%, 3%, 8% and 10%, respectively. The incidence and severity of bleeding symptoms were well correlated with the measured factor VII activity. In the severe case of factor VII deficiency (less than 1%) a home treatment program was started because of severe recurrent hemarthroses. This entailed transfusions of 20 U/kg body weight prothrombin complex or factor VII concentrate in case of acute bleeding approximately every three weeks. These transfusions have been carried out successfully without any problems. In contradiction, two brothers with hypoproconvertinemia (factor VII 8% and 10% respectively) reached an age of more than 70 years. Despite replacement therapy postoperative bleeding followed one appendectomy, whereas no postoperative bleeding followed patients requiring Achilles tendon lengthening and an above knee amputation and only slight bleeding followed a tonsillectomy. Based on our experience we suggest that in patients with factor VII deficiency of less than 10%, when undergoing surgery, should be maintained a minimal factor VII activity of 10--15% during the first three postoperative days.

Adolescent↗