Biomedical subjects

M Dittrich

Publications and source records attributed to M Dittrich.

61 records · Page 4Linked to original sources

PubMedDate not supplied

[Postoperative sonographic follow-up of brain tumors in childhood].

Postoperative neurosonography was performed in 69 babies and children after osteoclastic neurosurgery for primary cerebral tumors. Astrocytoma of the posterior fossa (26 cases) and medulloblastoma (25 cases) were frequent histological findings. Early postoperative bed-side examinations revealed reliably complications such as cerebral hemorrhage, edema or hygroma. Postoperative baseline studies were performed and reliability of sonographic criteria for tumor recurrence, such as high echogenicity and dense echotexture, were established. Regressive tissue changes under the usual postoperative cerebral radiation therapy and chemotherapy included transient increase in perifocal edema followed by tumor shrinking and cystic lesions or calcifications. Shunt dynamics were controlled by morphometrical studies of ventricular size. Long-time follow-up examinations were performed in most cases and covered periods of up to 4 years. Sensitivity of neurosonography for tumor recurrence was superior to non-contrast computed tomography; there were no false positive findings as proven by CT and magnetic resonance.

Adolescent↗

PubMedDate not supplied

[Kawasaki syndrome with acute gallbladder hydrops--case report and review of the literature].

We describe a 2 3/4-year-old boy with Kawasaki disease associated with the rare complication of acute hydrops of the gallbladder. Because of the severe abdominal symptoms cholecystectomy was performed. A review of the literature shows that about half of the patients had been operated upon. Therefore conservative treatment may provide complete improvement. Ultrasonography is not only very helpful in the diagnosis but also in follow-up.

Child, Preschool↗

PubMedDate not supplied

Branched oligoester microspheres fabricated by a rapid emulsion solvent extraction method.

Methyl formate was used as the solvent of biodegradable oligoesters for the fabrication of microspheres with encapsulated bovine serum albumin (BSA). The procedure of dispersion of the double emulsion of the w/o/w type and its dilution and solvent extraction is very rapid, taking only several minutes. A higher yield and better encapsulation efficiency were obtained with copolymers of DL-lactic acid with mannitol than with pure linear poly DL-lactic acid. The procedure was accelerated, and yields and encapsulation efficacy were enhanced by the addition of 5% methyl formate to the external water phase. The microspheres were smaller than 100 microm. No benefits were obtained from the addition of wetting agents or other additives to the intermediate (oligoesteric) phase. Further development should concentrate particularly on hydrodynamic conditions and optimization of the composition of the external phase.

Animals↗

PubMedDate not supplied

Antigenic and adjuvant activities of branched aliphatic oligoester (M-DL-LA) microspheres with incorporated bovine rotavirus.

Branched aliphatic oligoester microspheres (msp) with incorporated rotavirus were used to induce the production of systemic and mucosal antibodies in mice. The msp with a mean diameter of 7.4 microm were prepared by the w/o/w technique. The mice were immunized intraperitoneally or orally. High ELISA titres of systemic and local IgG and IgA antibodies were indicative of rotavirus incorporation and of the adjuvant activity of msp. Oral immunization with a split dose administered on three consecutive days, resulted in the production of systemic IgG and IgA antibodies, but failed to induce the production of mucosal antibodies even if the immunization dose was increased threefold. Specific antibodies were detectable in faeces of orally immunized mice only after another triple administration of the same dose in the fourth week of the experiment. Reactions of blood serum IgG with the structural viral proteins VP4, VP6, and VP7 were demonstrated by western blotting. Both systemic, and faecal IgA antibodies were specific for the VP6 protein and the dimeric form of the glycoprotein VP4.

Adjuvants, Immunologic↗

PubMedDate not supplied

Release of albumin from oligoester plastic matrices: effect of magnesium oxide and bivalent stearates.

Biodegradable implantable matrices containing bovine serum albumin were prepared from oligoesters by melting, and subsequently tested on in vitro albumin release. The linear poly (DL-lactic acid) and the branched terpolymer of DL-lactic acid, glycolic acid, and mannitol were synthesized. Products were of similar molecular weight and possessed different thermal and swelling characteristics. Oligoesters were loaded with 4% albumin and plasticized by 30% triacetin. Other additives added into the matrices as albumin stabilizers were divalent stearates and magnesium oxide. The influences of oligomer molecules constitution, divalent ion stearates or magnesium oxide addition, and triacetin concentration on the albumin release were quantified. SDS-PAGE revealed protein hydrolysis during the dissolution tests.

Albumins↗

PubMedDate not supplied

A contribution to the evaluation of microcapsules by light microscopy.

Light microscopy has been used for the evaluation of the internal and external structure of dry microcapsules. The method involves surface and penetrative staining with various dyes after which the microcapsules were embedded in suitable optically translucent material. Using this method the core material, its shape and position within the microcapsules either in total or as subunits of the core are clearly distinguishable from the wall material. The surface characteristics of the microcapsules can be observed with either light or fluorescent microscopy after staining with a fluorescent dye. Furthermore, it is a relatively simple and inexpensive method by comparison with the scanning electron microscopy. The natural character of microcapsules, without any artificial structures, has been maintained. It could serve as a routine auxiliary method for complex evaluation or control of the microencapsulation process and its optimization.

Drug Compounding↗

PubMedDate not supplied

Influence of total surface area of core material on yield of deposited coacervate.

Influence of total surface area of core material on yield of deposited coacervate was evaluated. A simple coacervation method was employed solvent-evaporation method were used as a model core substance. A mixed polymer system--aqueous solution of gelatin and potassium salt of cellulose acetate phthalate--was used as a wall material. A sodium sulphate solution acted as a desolvating agent. Results obtained clearly show an opposite effect of the size of core material and derived total surface area on the yield of attached coacervate. While keeping the amount of core material constant, the amount of deposited coacervate increased both with the decreased size of core particles (increased total surface area), and increased concentration of desolvating agent. The proportion of wall material gradually increases with the increased concentration of sodium sulphate solution in the range from 1 to 9 per cent of the weight of microcapsules. Analysis of variance was used for the evaluation of obtained data.

Capsules↗