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Biomedical subjects

F Hoffmann

Publications and source records attributed to F Hoffmann.

At least 91 records · Page 5Linked to original sources
PubMed1991

The total surface and number of occlusal contacts in the static and dynamic occlusion of the teeth. Development of the methods.

For reasons of different data in literature on occlusal parameters and their metric registration at the beginning of the eighties two methods, independent from each other, were developed to registrate the total occlusal contact area and the number of occlusal surfaces of contact on dental casts--the capacity measuring method and the quasi-planimetry method. The results obtained independently from each other show a high degree of correspondence. Because of its easy handling the method of quasi-planimetry was further developed and used for direct analysis of enorally obtained wafers of different characteristics. The total surface of occlusal contacts in the static occlusion ran up to 4-6 mm2, and the number of stops to 19-30. The method of qualitative and quantitative analysis of occlusal parameters is improved with a modern system of digital analysis. The results obtained up to now admit the conclusion that the occlusion of the teeth represents an individual condition of high variability.

Adolescent↗
PubMed1991

[Psychosocial problems in patients with chronic osteomyelitis].

52 patients suffering from a chronical bone infection were followed up with a special interest in psychosocial problems. In all cases psychosocial disturbances of different importance were evaluated. Possible causes have to be seen in long time of hospitalisation (average = 304 days), and apparent inadequate enlightenment of patients and in functionally and cosmetically insufficiencies. Conclusions are shown for the management in treatment of chronical bone infections.

Activities of Daily Living↗
PubMed1990

Pollen germination is impeded by tap water.

Pollen germination in vitro is totally inhibited in tobacco (Nicotiana tabacum) and other species if tap water is used to prepare the germination medium. This effect is already fully present if tap water accounts for only 25% of the medium. Furthermore, the pollen grains deteriorate rapidly and the culture medium turns yellowish-brown. The water toxicity is not caused by one or several compounds regularly monitored by the water authorities but can be removed by ion exchange purification. Although the factor(s) responsible for the inhibition were not identified, the study clearly shows the presence of such a contaminant in three different Orange County (Southern California) water wells. The fact that a fundamental botanical process like pollen germination is inhibited by a factor in drinking water not included in water quality control causes some general health concern. In addition, crop yield might be largely reduced if overhead spray irrigation with this water is utilized. The experiments also suggest that pollen germination in vitro could serve as a sensitive and simple bioassay for water quality.

Journal Article↗
PubMed1990

Accuracy of the microkeratome keratectomies in pig eyes.

Keratokyphosis is a procedure of lamellar refractive corneal surgery in which corneal tissue does not have to be frozen. Corneal lamellae of 30 pig eyes were separated with either the Berlin microkeratome developed for keratokyphosis or the Barraquer microkeratome. The layer thickness was measured within the optical area at 25 measuring points 0.2-mm apart using the Universal Measuring Microscope. Corneal lamellae separated parallel to the surface by means of the Berlin microkeratome showed layer-thickness differences of 0.008 +/- 0.028 mm in the optical zone between the beginning and end of the incision. When using a convex applanation surface in the microkeratome with an optical zone of 5 mm and a vertex of 0.22, 0.2, and 0.15 mm, the vertex of the central part of the optical zone in the corneal disc attained a value of 0.114 +/- 0.018 mm instead of 0.114 mm (100%), 0.075 +/- 0.015 mm instead of 0.105 mm (72%), and 0.076 +/- 0.014 mm instead of 0.080 mm (84%) (mean +/- standard deviation [SD]). When using a concave applanation surface with the same vertex, it attained 0.076 +/- 0.020 mm (67%), 0.075 +/- 0.019 mm (72%), and 0.067 +/- 0.027 mm (84%). The measured vertex of the corneal lamellae was shifted up to 0.8 +/- 0.5 mm in the feed direction of the microkeratome, probably due to the frictional forces acting on the blade during the cutting process. After separation of the lamellae, the cut surface of the eye was measured planimetrically.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

[Combined valuation of the success of therapy of orthodontic anomalies, periodontal diseases and dental caries].

Using the DMF/T, GPM/T and CPITN-index systems, the numerical evaluation method according to Eismann and measuring the occlusal contact areas in static occlusion in 101 orthodontically treated adolescents and young adults the effect of complex preventive and therapeutic programs was studied. The used parameters allow to characterize oral health status. After completing the orthodontical treatment there is a need to continue preventive programmes and therapeutic interventions in adults to reach stable oral health conditions.

Adolescent↗
PubMed1990

[Psychosocial factors of preserving health? Prospective studies of breast cancer, bronchial cancer and fibrocystic mastopathy].

Do psychosocial factors affect the development of health? 156 patients were interviewed and tested before a breast biopsy or before the initial medical treatment of lung cancer. Multiple regressions examined the influence of age, diagnosis (tumor stage) and different psychosocial parameters as dependent variables the development of health after 2 or 5 years as independent variables. The breastbiopsy-group (n = 52) shows five psychological variables being effective in a positive (health promoting) manner: autonomy, emotional outlet, expression of one's needs, family support, lack of life stress. In lung cancer (n = 104) the development of health 2 years after diagnosis is only influenced by the type of tumor (small cell versus non small cell) and by the initial tumor stage. A structuralequation model (LISREL) shows for the first 3 months of illness that almost exclusively biological variables have an influence on psychological variables. Despite this family dynamics had a moderate effect on the patient's general wellbeing (Karnoffsky-Index).

Adult↗
PubMed1989

[Objectivization of the methods for recording the total contact surface and the number of occlusal contacts in static occlusion].

The occlusal contacts of teeth in a dentition have been analysed metrically with the aid of a new method. The outstanding advantage of this method is offered by the fact that the contacts of teeth are registered immediately in the subject and then evaluated with the aid of the teleplanimetric measuring variant. From error computation it follows that the method leads to reproducible and largely objective results. In 84 subjects with an average age of 16.9 +/- 3.7 years the total contacting area and the number of contacts in static occlusion were determined and examined with respect to specific groups.

Adolescent↗
PubMed1989

[Arthroscopic semitendinosus-plasty with lateral extra-articular stabilization in anterior knee joint instability].

Within the framework of a prospective study, 40 patients were examined postoperatively 12 months after their anterior cruciate ligament had been replaced by a doubled semitendinosus tendon arthroscopically combined with a lateral extra-articular procedure. "Second look" arthroscopy was possible in four cases. Evaluation was conducted according to the system of Müller and the Lysholm scoring system. According to the Müller system very good or good results were achieved in 97.5%; 95% of the patients achieved 91-100 points in the Lysholm scoring system. No substantial restrictions in the knee joint's range of movement were reported; there were also no other complications. The operative technique and the rehabilitation regimen are documented.

Adolescent↗
PubMed1989

A simple plant and tissue culture growth chamber for the regeneration of tobacco mesophyll protoplasts.

The isolation and regeneration of tobacco mesophyll protoplasts from fully developed leaves, an important methodological step in plant genetic engineering as well as in plant cell biology and physiology, has been proven unreliable to the extent that it has become a significant setback to basic research. This unfortunate situation is primarily due to the suboptimal physiological state of greenhouse-grown protoplast donor plants. A technically simple and inexpensive method, based on the utilization of commercial Phototron units, is described for the production of suitable tobacco donor plants. Furthermore, a modified version of such a culture unit can be used to regenerate plants from protoplast-derived calli.

Atmosphere Exposure Chambers↗
PubMed1989

Predisposing factors in corneal graft rejection.

During a period of 12 years, 390 patients were treated with perforating keratoplasty and given regular annual follow-ups. Of these, 357 records were evaluated, and there was a 20% incidence of immunoreactions. The transplants were assessed according to four criteria and subdivided into a low-risk and a high-risk group. For high-risk patients, the relative risk of developing an immunoreaction was 2.9 times greater with subdivision according to the preoperative diagnosis, 2.1 times greater with a transplant diameter of 7.5 mm or more, 2.6 times greater with compatibility between fewer than two HLA-B or -DR antigens of the donor and recipient, and 4.2 times greater with blood or fibrin in the anterior chamber on the first postoperative day. There was a linear relation between the frequency of being placed into the less-favorable-prognosis group and the occurrence of an immunoreaction.

Child↗
PubMed1987

[Significance of progesterone production in regulating the menstrual cycle].

Premature luteolysis, which can be brought about by injection of a crystalline suspension of estradiol into the ovary carrying the corpus luteum, is cancelled out by a concomitant injection of an appropriate dose of a crystalline progesterone suspension, together with a simultaneous increase in the plasma progesterone level. The authors discuss whether preovulatory production of progesterone has a similar protective influence on the growth and estrogen and androgen production of the vesicular ovarian follicles and the dominant follicle.

Corpus Luteum↗
PubMed1987

[Combination of phacoemulsification and trabeculectomy. Results of a retrospective study].

Combined trabeculectomy and phacoemulsification was performed on 21 eyes with poorly controlled glaucoma (15 open-angle glaucomas, 5 capsular glaucomas, and one secondary glaucoma) and coexisting cataract. In 20 of these eyes there was severe glaucomatous damage of the optic nerve with visual field loss. With the procedure used by the present authors there was a higher incidence of choroidal detachments, whereas other complications occurred at a lower rate than reported by other authors combining cataract extraction and trabeculectomy. Mean IOP was lowered from 25.7 +/- 6.1 to 17.1 +/- 3.2 mmHg after 18 months. Thirteen patients (62%) required no medication, while 5 (24%) required additional therapy for sufficient control of IOP (less than or equal to 21 mmHg). The results indicate that the combined phacoemulsification and trabeculectomy procedure may be a useful approach in eyes with severe glaucomatous damage and cataract.

Aged↗
PubMed1987

Human immunodeficiency virus transmission by organ donation. Outcome in cornea and kidney recipients.

The human immunodeficiency virus (HIV) is reportedly transmitted by sexual contact, sharing of infected needles among intravenous drug abusers, blood and blood products, artificial insemination, and kidney transplantation. This study reports on cornea and kidney recipients of two HIV-infected donors. HIV was transmitted to two kidney recipients who developed symptoms of acute HIV infection (i.e., fever, leukopenia, mild thrombopenia, splenomegaly) starting 12 days after transplantation. These signs of acute infection ended with seroconversion of HIV antibodies on approximately the 56th day after transplantation. The three cornea recipients showed no signs of acute infection and no HIV antibodies were detected up to three years after transplantation. The nontransmission observed in our cases, however, may not be representative of cornea transplantations in general. HIV is neurotropic in the later stages of the disease, and transmission of other neurotropic viruses like rabies and Creutzfeldt-Jakob disease by cornea transplantation has been reported. All tissue and organ donors should be tested for anti-HIV prior to donation.

Acquired Immunodeficiency Syndrome↗