Biomedical subjects
Publications and source records attributed to H Hofmann.
This case study describes the diagnosis of a thrombosis of the inferior vena cava in the course of a sonographic examination of the upper abdomen. Using ultrasound, large abdominal vessels can be examined easily. Following diagnosis, sonographic examinations under intensive care allowed observation of the further progress of the thrombus up to its dissolution.
Iatrogenic damage to the orbital fascial system during strabismus surgery may lead to adherences with resulting problems of motility. To prevent new adherences in revisional surgery, several materials were tried, with varying degrees of success. The authors tested Polyglactin 910, popular as a suture material in strabismus surgery, in the form of a net. The material is hydrolytically soluble. Since the tissue response is finished before dissolution of the implant, it seemed that Polyglactin would be a suitable barrier to the formation of adhesions in Tenon's capsule. The implant was applied in 11 patients, some of whom had already undergone several strabismus operations and had adhesions at the surgical site. In one case the implant was used in a primary procedure. In one patient revisional surgery was needed four weeks after surgery because of overeffect, and this provided an opportunity to investigate the implanted area histologically.
Sperm-mucus interaction under in-vitro or in-vivo conditions might be affected by microorganisms colonizing the reproductive tract. In order to study the influence of antimicrobial therapy, an extensive microbial screening was performed including Chlamydia trachomatis, Mycoplasma hominis, Ureaplasma urealyticum, Neisseria gonorrhoeae, a broad spectrum of potentially pathogenic aerobic and anaerobic bacteria, Trichomonas vaginalis, herpes simplex virus and yeasts. One-hundred-and-six couples with a mean duration of infertility of 5.5 years (range 1-12 years) and with isolation of potentially pathogenic microorganisms in semen samples and/or cervical swabs were submitted to a prospective pilot study. None of the patients displayed signs or symptoms of infection in the lower genital tract. Before and after specific therapy, based on antimicrobial susceptibility testing, sperm analyses and in-vitro sperm penetration meter tests (SPMT) (Kremer) were performed. SPMT was evaluated with cervical mucus of patients' wives, collected after a standardized oral treatment with oestrogens and, additionally, in a crossed manner with cervical mucus and spermatozoa of fertile donors. The success of antimicrobial therapy was controlled by repeating the same microbial screening and was 96%. However, there was a marked change in the microbial pattern. A comparison of the results of sperm analyses before and after treatment revealed neither significant differences for sperm volume, sperm count, propulsive motility, morphology, vitality, pH, fructose concentration or number of round cells, nor was there a significant influence on the cervical index and the number of leukocytes in cervical mucus.(ABSTRACT TRUNCATED AT 250 WORDS)
In 17 patients with cardiac extrasystoles, prostaglandin (PG) F2a (= alpha) administered intravenously at consecutive infusion rates of 25 to 100 micrograms/min showed the following effects in a dose-dependent manner: prolongation of total electromechanical systole, pre-ejection period, and left ventricular ejection time, indicating a negative inotropic activity, increase in systolic and diastolic blood pressure, and incidence of side effects. An additional 2 patients were excluded from the uniform evaluation because the PGF2a dosage was changed owing to a clear antiarrhythmic action in one and serious side effects in the other. The results supplement clinical-pharmacological findings with PGF2a.
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The amino acid sequence of the 212-residues-long N-terminal aggregation and cross-linking region of the alpha 2(IV) chain of human basement membrane collagen is presented. Comparing this with the primary structure of alpha 1(IV)7S [Glanville et al. (1985) Eur. J. Biochem. 152, 213-219] revealed a high degree of similar subdivisions in three functional regions. These are the 21-residue-long N-terminal non-triple-helical regions (NH1) containing cysteine and lysine residues which are putative cross-linking sites, a 117-residue-long triple-helical region (TH1) responsible for the aggregation of four molecules to form the 7S domain and which also possess cross-linking sites, and finally a 10-residue-long non-triple-helical region (NH2) which introduces the first of many flexible areas into the triple helical body of the molecule [Hofmann et al. (1984) J. Mol. Biol. 172, 325-343]. Computer calculations of interaction scores between parallel and antiparallelly aligned triple-helical regions (TH1) of the 7S domain allowed the prediction of a detailed model for the structure of the 7S complex which agreed well with models based primarily on electron micrographs of rotary shadowed type IV collagen tetramers. The results indicated that the assembly of the 7S domain is directed by hydrophobic interactions and is self-limiting to a tetramer. The most favourable chain configuration is alpha 2-alpha 1-alpha 1.
In this paper, we show that the procoagulant action of Bothrops atrox venom is due in part to a protein component that activates prothrombin. The venom prothrombin activator was purified by ion-exchange chromatography and gel filtration. It was separated from a protease by affinity chromatography in a p-aminobenzamidine-CH-Sepharose column. It is a protein of about Mr 70,000, consisting of a single polypeptide chain. We have studied the kinetics of activation of prothrombin under different experimental conditions. The prothrombin activator from B. atrox venom is insensitive to reagents of serine and thiol proteases but is inactivated by ion chelators and by various divalent ions. These results suggest that it is a metalloenzyme. The prothrombin activator from B. atrox venom is inactive on the chromogenic substrates S-2337 and S-2238, and it is selective for prothrombin since it does not act on other blood coagulation factors such as fibrinogen and factor X. We have also studied the pattern of peptide cleavages produced in the human prothrombin molecule during the activation by the activator from B. atrox venom and compared it to that obtained with ecarin, a prothrombin activator from Echis carinatus venom. In the presence of thrombin inhibitors, e.g., hirudin, we found that the activators from B. atrox venom and ecarin act in a similar, or identical, manner by producing a thrombin intermediate, meizothrombin. In the absence of thrombin inhibitors, several peptides are generated, and alpha-thrombin is produced as a consequence of meizothrombin action.
We have characterized and purified the two components of the venom of Bothrops atrox that activate the coagulation factor X. Activator 1 and activator 2 were separated by ion-exchange chromatography but otherwise presented similar characteristics. They consist of a heavy polypeptide of Mr 59,000 and either one or two light chains forming a doublet of Mr 14,000-15,000. They are inactive on synthetic substrates and on prothrombin or fibrinogen and thus appear to act specifically on factor X. They are not sensitive to inhibitors of serine proteases or thiol esterases. The activation of factor X is activated by Ca2+ ions with a Hill coefficient of 2.4 and is inhibited by Hg2+, Ba2+, and Cd2+. Its pH dependency suggests that the activity depends on the ionization of a group with an apparent pK of 6.9. We studied the cleavage of purified bovine factor X by B. atrox activators and compared it to that obtained with the factor X activator from Vipera russelli venom. Like the physiological activators, the venom's activators cleave the heavy chain of factor X, producing the activated factor Xa alpha. They produce however two other cleavages: one near the N-terminal end of the heavy chain of factor X, generating factor Xmu, and a second one located at one extremity of the heavy chain of factor Xa alpha, generating factor Xav.
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Visual evoked potentials (VEPs) to pattern reversal and psychophysical contrast sensitivity (CS) were tested in five patients with Uhthoff's symptom before and after exercise. Four of the cases were related to a demyelinating disease and one patient had a severe brain injury. Uhthoff's symptom occurred also in neuropathies without previous clinical neuritis and in eyes with normal latency time of the VEPs. A depression of CS was observed by all five patients after exercise; a transient "overshoot" of CS following the depression was present in three of the patients. VEP amplitudes were reduced by exercise in three cases. Responses by stimulation with small checks were more affected. Paradoxical increased VEP amplitudes after exercise in the presence of a loss of psychophysical CS were found in one case.
Two-hundred-and-thirty-three asymptomatic couples with a mean duration of infertility of 5 years were submitted to postcoital testing (PT) and to sperm penetration meter test (SPMT) and simultaneous microbial screening. Cervical swabs and semen specimens were collected for culture of Mycoplasma hominis, Ureaplasma urealyticum, Chlamydia trachomatis, Neisseria gonorrhoeae, other potentially pathogenic and commensal aerobic and anaerobic bacteria, herpes simplex virus, vaginal swabs for Trichomonas vaginalis and yeasts. Results of microbial screening were analysed with regard to sperm penetration ability into wives' cervical mucus in vivo and in vitro, but no marked influence was revealed for most microorganisms. Samples of only one of the 233 couples proved to be completely sterile. The findings suggest that in asymptomatic patients microbial colonization is of minor importance for sperm-mucus interaction.
Ureaplasma urealyticum und Mycoplasma hominis are frequently isolated from the urogenital tract of sexually active persons. Their pathogenetic role in urogenital infections and infertility are still controversial. U. urealyticum can cause urethritis and most likely also chronic prostatitis. M. hominis can cause cystitis, salpingitis, and postpartal fever in women and meningitis in newborns. M. genitalium was recently isolated from patients with urethritis and salpingitis. The diagnosis is made by the cultivation of mycoplasmas in high concentrations and rising antibody titers in the serum. As in chlamydial infections, the therapy of first choice is tetracyclin. M. hominis can also be treated with clindamycin, U. urealyticum with erythromycin.
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As a consequence of the rubella epidemic in Austria in 1979, prophylaxis against this disease was intensified. In spite of this measure, however, there was an increase in cases of rubella in 1984/85. The peak incidence in both years occurred in May. In 1984, most cases were found in Vienna, Lower and Upper Austria, and Salzburg, whereas in 1985, Styria and Vienna were most affected. The clinical diagnosis of rubella was confirmed serologically in 685 patients. Of these, 151 were pregnant women and 104 were women of childbearing age who gave no information as to pregnancy. Due to the virtually complete recognition of cases, which usually led to therapeutic abortion, only 7 cases of intrauterine rubella infection were recorded. In spite of the vaccination of all prepuberal schoolgirls, of women at occupational risk, and of seronegative women after delivery, 10% of women of childbearing age still have no reliable immunity (HI titre 1:32) to rubella. This situation can be improved only by testing women at around 20 years of age for immunity (irrespective of their vaccination status) and vaccinating them if necessary.
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In order to classify events of bleeding in early pregnancy (7th-16th week of pregnancy), an ultrasonic examination was carried out on 72 pregnant women, as well as tests establishing the HCG-secretion in the early morning urine and the progesterone level in the serum before commencing hormone therapy. The collected medical evidence was compared with standard curves. In order to test its prognostic validity, it was related to the termination of the pregnancy. In cases of miscarriage, the placenta was examined histologically and the progesterone level decrease registered over 48 hours. In 34 women, the pregnancy ended with a birth; in 26 (76.5%) of these cases the progesterone values were with the normal area. The HCG-secretion was normal in 25 (74.3%) patients. The sonographic classification indicated an intact pregnancy in every case. In 38 cases the pregnancy was disturbed. In this group of patients, the progesterone level in 36 cases (94.8%) and the HCG values in 27 patients (71.1%) were below the normal. Signs of life were absent in 37 pregnancies (97.4%) in the ultrasonic examination. By virtue of the statistical evaluation of this data, a high reliability can be attributed to the sonographic evidence with regard to the correct prognosis for bleeding in early pregnancy.
Artificial gels prepared from Cu2+-ions and hyaluronic acid were studied in the electron microscope and compared with the native vitreous body. Additionally, the authors attempted to produce transparent gels from the native constituents of the vitreous body, namely collagen and hyaluronic acid. Mixing of solutions of these constituents formed no gels but white precipitates. The ultrastructure of these precipitates was also studied in the electron microscope.