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Biomedical subjects

T Heinrich

Publications and source records attributed to T Heinrich.

31 records · Page 2Linked to original sources
PubMed1992

[Results of conventional retinal detachment surgery. II. Changes in refraction].

In a comparative study we examined the refractive changes in 117 patients following conventional buckling retinal detachment surgery. Of these, 54 had a segmental scleral buckle, 18, an encircling buckle, and 45, a combination of both methods. Comprising about 2D, the changes in spherical equivalent were most marked in the patients who had combined operations. A correlation exists between buckle height and extent of refractive change (p = 0.0297).

Adolescent↗
PubMed1992

[Results of conventional retinal detachment surgery. III. Orthoptic results].

In a comparative study we examined orthoptic side effects in 117 patients following conventional retinal detachment surgery. Of these, 54 had had a segmental scleral buckle, 18 a simple encircling band and 45 encircling band combined with a radial buckle. Persistent diplopia was found in 6% of cases following segmental buckles, in 11% following simple encircling procedures and in 20% following combined operations with encircling bands and segmental buckles. The incidence of diplopia was more than 30% in cases with high encircling buckles.

Adolescent↗
PubMed1992

Identification of the gene encoding transcription factor NusG of Thermus thermophilus.

The nusG gene of Thermus thermophilus HB8 was cloned and sequenced. It is located 388 bp downstream from tufB, which is followed by the genes for ribosomal proteins L11 and L1. No equivalent to secE preceding nusG, as in Escherichia coli, could be detected. The nusG gene product was overproduced in E. coli. A rabbit antiserum raised against the purified recombinant NusG reacted exclusively with one protein band of T. thermophilus crude extracts in Western blot (immunoblot) analyses, and no cross-reaction of the antiserum with E. coli NusG was observed. Recombinant NusG and the reacting T. thermophilus wild-type protein had identical sizes on sodium dodecyl sulfate-polyacrylamide gels. T. thermophilus and E. coli NusG have 45% identical and 22.5% similar amino acids, and similarities between the two proteins are most pronounced in carboxy-terminal regions. The T. thermophilus nusG gene could not rescue a nusG-deficient E. coli mutant strain.

Amino Acid Sequence↗
PubMed1991

[Contact lenses--possibilities, problems and hazards].

Because use of contact lenses has become more common, knowledge of the basics is necessary. The most important kinds and materials of contact lenses, the indications for their application, and especially the important complications are illustrated by some clinical examples. Some simple first-aid measures are presented.

Adult↗
PubMed1991

Long-term treatment effects in patients with bilateral retinoblastoma: ocular and mid-facial findings.

A total of 99 patients with bilateral retinoblastoma who had been treated between 1965 and 1982 were reexamined in April 1988 to study the late effects of treatment. Their median age at the follow-up visit in 1988 was 16 years (range, 6-27 years), and the median follow-up was 15 years (range, 6-26 years). All patients underwent a full eye examination, morphometric measurements of the mid-face and genetic counselling. Each eye or orbit and the corresponding side of the patient's mid-face were evaluated separately, resulting in 198 data sets from 99 individuals. Subjects were divided into four treatment groups according to whether photo- and cryo-coagulation, enucleation, radiation therapy or various combinations thereof were used. In all, 81 eyes had a visual acuity of greater than 0.4 (in 23 of these, however, only with low-vision aids). Within a dose range of 36-51 Gy, the location of the tumor (36%) or cataract (15%) were the main factors responsible for poor visual acuity, whereas radiation retinopathy and/or optic neuropathy occurred in only three cases. Cataracts were more frequently observed following orthovoltage as compared with megavoltage therapy (P = 0.012). A total of 72 eyes had been enucleated and had not received radiation therapy at any time. Cosmetic results (as measured by several parameters) in these cases were significantly better then those in 28 subjects who underwent combined radiation therapy and enucleation. As defined by various subjective as well as objective findings, mid-facial hypoplasia occurred significantly more often following orthovoltage as compared with megavoltage therapy.

Adolescent↗
PubMed1991

Risk factors for metastases in patients with retinoblastoma.

The study is based upon a review of data from 583 consecutive patients with retinoblastoma over the years 1956 to 1986. Mean follow-up was 8 years, and median was 5.5 years. In 41 patients, metastases developed within 5 years. The influence of clinical and histopathologic risk factors on the occurrence of metastases was first analyzed by univariate tests. Significant variables were then reevaluated using the Cox proportional hazards method. Four factors were found to be independently associated with the development of metastases: optic nerve invasion with and without involvement of the resection line, choroidal invasion and enucleation of an affected eye more than 120 days after initial diagnosis. The 5-year metastatic risks associated with these factors were 67%, 13%, 8%, and 4%, respectively. The relative risk estimate, calculated from the Cox model, was used for a score classification with groups of low, medium, and high metastatic risk. The 5-year incidence of metastases was 4%, 43%, and 68%, respectively.

Adolescent↗
PubMed1991

[Healed (?) amoebic keratitis].

Acanthamoeba keratitis was seen in two contact-lens wearers. In both cases, this finding was verified by microbiological examination of conjunctival swabs and of the lens solution. One patient had perforating keratoplasty. While neither vital amoebae nor cysts could be detected in the host corneal explant, immunohistochemical examination revealed fluorescence-positive fragments which probably correspond to incomplete cycstic walls.

Acanthamoeba Keratitis↗
PubMed1991

[Risk of metastasis in retinoblastoma].

580 patients with retinoblastoma were analysed retrospectively. Median follow up was 5.5 years. 41 patients developed metastases within 5 years. Clinical and histopathological risk factors were analysed by univariate tests with regard to the occurrence of metastases. Significant variables were then reevaluated using Cox proportional hazards method. Four factors correlated independently with the development of metastases: optic nerve invasion with involvement of the resection line, optic nerve invasion without involvement of the resection line, choroidal invasion and enucleation of an affected eye more than 120 days after initial diagnosis. The regression coefficient beta of the Cox-model was used for a score classification with groups of high, medium and low metastatic risk. The 5-year incidence of metastases was 68%, 43% and 4% respectively.

Adolescent↗
PubMed1990

New and recurrent tumor foci following local treatment as well as external beam radiation in eyes of patients with hereditary retinoblastoma.

The study is based on a retrospective analysis of data from 200 patients with hereditary retinoblastoma. Apart from four unilateral cases with a positive family history all patients had bilateral disease; 229 appeared suitable for conservative treatment while 167 eyes had to be enucleated. Primary local treatment was performed in 102 eyes, while 127 eyes received primary external beam radiation using a linear accelerator. Follow-up was adjusted by life tables, with 75% of the patients being observed longer than 2 years. Using life-table statistics new and recurrent tumors were found in 41% of all patients and in 95% of these cases they were noted within 26 months after initiation of therapy. Among eyes treated with primary external beam radiation new and recurrent tumors were observed significantly less frequently when 50 Gy (22% compared with 49% after 40 Gy) and a highly accurate beam alignment technique (22% compared with 48% after alignment to the outer bony canthus) were applied. The incidence of recurrent tumors following primary local treatment did not differ significantly with regard to the application of either photo- or cryocoagulation (28% vs 33%), while no recurrence was observed among tumors that were suitable for primary treatment using ruthenium or cobalt plaques.

Brachytherapy↗
PubMed1990

A quantitative assay for tyrosine sulfation and tyrosine phosphorylation in peptides.

A method was developed to measure sulfation and phosphorylation of tyrosine in proteins after alkaline hydrolysis, ion-exchange chromatography, reaction with [3H]dinitrofluorobenzene and subsequent thin-layer chromatography. The method allows the detection of 10-20 pmol of modified tyrosine and was applied to determine the content of tyrosine-phosphate and -sulfate in fibrinogens, thyroglobulin, alpha-casein, cytochrome c and glyceraldehyde dehydrogenase.

Chemical Phenomena↗
PubMedDate not supplied

Comparison of methods for the analysis of 226Ra in water samples.

226Ra is one of the key nuclides among the natural radionuclides from the point of view of radiation protection. For monitoring the radiation exposure risk along the water pathway it has to be measured routinely with low detection limits. Because of the properties of 226Ra and its progenies, a number of quite different methods are possible for this purpose. This paper presents a comparison of routine techniques for the determination of 226Ra in water samples as applied by the authors.

Humans↗
PubMedDate not supplied

[The question of midface growth inhibition following retinoblastoma treatment in early childhood].

99 patients treated for bilateral retinoblastomas in the University Hospital of Essen between 1965 and 1983 were followed up for midface growth inhibition for an average period of 15 1/2 years. Depending on the type of treatment employed the patients were divided into four groups: Local tumor treatment using cryotherapy or laser techniques, ophthalmectomy alone, radiotherapy alone, and combined ophthalmectomy and radiotherapy. Statistically significant differences between the treatment groups were found regarding such symptoms as hypoplasia of the zygomatic bone, hypoplasia of the transversal orbit, hypoplasia of the temporal fossa, hypoplasia of the root of the nose as well as hypotelorism and enophthalmos. Combined surgery and radiotherapy caused the most severe growth disorders, followed by radiotherapy alone and ophthalmectomy alone. With local treatment detectable growth disorders were observed, if at all, only as a result of contralateral radiation scatter. Orthovoltage radiotherapy was found to produce growth disorders of significantly higher severity than megavoltage radiotherapy.

Adolescent↗