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Biomedical subjects

F Bauer

Publications and source records attributed to F Bauer.

At least 19 recordsLinked to original sources

A retinoic acid receptor alpha antagonist selectively counteracts retinoic acid effects.

Retinoic acid (RA) exerts its pleiotropic effects on cell growth and differentiation through the activation of a family of transcription factors-the RA receptors (RARs). Three subtypes of these receptors exist, RAR alpha, RAR beta, and RAR gamma. The receptors are differentially expressed in different cell types and stages of development, suggesting that they may regulate different sets of genes. We have identified a synthetic retinoid with the characteristics of a selective RAR alpha antagonist. This antagonist counteracts RA effects on HL-60 cell differentiation and on B-lymphocyte polyclonal activation. Beyond its potential practical relevance, this and other specific antagonists will be useful to dissect the RAR system and to assign to one given receptor each of the many RA-regulated functions.

Animals

Nosocomial transmission of hepatitis B virus associated with the use of a spring-loaded finger-stick device.

BACKGROUND AND METHODS: From June 1989 through March 1990, 26 patients, of whom 23 had diabetes, contracted acute hepatitis B virus (HBV) infection in a hospital in California. All 26 patients and one HBV carrier (also a diabetic) had been admitted to a single medical ward during the six months before the case patients became infected with HBV. To determine the source of the infection, we conducted a retrospective cohort study of the 72 patients with diabetes who had been admitted to the ward from January through December 1989 and a case-control study comparing the 3 nondiabetic patients who contracted hepatitis with 20 nondiabetic controls. RESULTS: The retrospective cohort study of all the patients with diabetes who were admitted to the ward during 1989 found that those who underwent capillary blood sampling by finger stick with a spring-loaded lancet device were more likely to contract HBV infection than those who did not have finger sticks (attack rate, 42 percent vs. 0 percent; P = 0.08). In addition, a dose-response relation was observed between the number of finger sticks received and the frequency of hepatitis B (P = 0.002). The case-control study found that all 3 of the nondiabetic patients who contracted hepatitis underwent finger-stick blood sampling with the device, as compared with none of the 20 nondiabetic controls (P = 0.0006). A review of nursing procedures indicated that the platform of the device was not routinely changed after each use; this finding suggested that contamination of the platform by HBV-infected blood was the mechanism of percutaneous transmission of HBV. CONCLUSIONS: Proper use of finger-stick devices as well as strict adherence to universal precautions to avoid contamination by blood are required to decrease the possibility of transmission of blood-borne pathogens among hospitalized patients.

Acute Disease

[Effect of heat on the solubility and the electrophoretic behavior of myoglobin].

The heat stability of beef myoglobin was investigated by means of its solubility and intensity of protein bands separated by isoelectric focusing. A method for the sensitive determination of myoglobin in the extracts was developed based on its ability to form a red dye by the oxidative coupling of 2,4-dichlorophenol and 4-aminoantipyrine in the presence of hydrogen peroxide. By this method, myoglobin could be determined to a concentration of 0.01 mg/ml. For the detection of electro-focused myoglobins, o-dianisidine has proved to be the most sensitive compound. The myoglobin content of the extracts, according to the intensity of the myoglobin bands in the electrophoretic gel, decreased with increasing temperature and heating-time. However, the position of the bands was not changed by the heat treatment.

Animals

Effects of setting eggs small end up on hatchability and posthatching performance of broilers.

1. Hatchability of fertile eggs incubated with their small ends up (SEU) was 16 to 27% lower than for eggs set with their large ends up (LEU). In addition, the SEU position produced more nonviable chicks. 2. There were no differences in post-hatching performance between the two incubation treatments. 3. A survey in a commercial hatchery revealed that the frequencies of eggs set upside down by mistake varied from 0.3% to 3.4%. The setting of eggs upside down was attributed not to difficulties in distinguishing the large and small ends of the eggs but to human error. A decrease in the number of Grade-A chicks of about 0.2% was observed for every 1% of eggs set upside down, suggesting it may be of economic importance to ensure that the eggs are set properly with their large ends up.

Animals

[Diagnostic value of the early auditory evoked potentials in acute cranio-cerebral trauma in children].

The brainstem auditory evoked potentials were recorded in 54 children within the first 48 hours after a head trauma of different degree. In comparison with an age--appropriate standard group there are changed BAEP in 51% of the examined children after head trauma. The abnormalities mainly consist in changes of the wave--morphology, the latencies of the waves 1, 3 and 5 were significantly prolonged. The interpeak--intervals only unessentially differ from the standard group. The detected BAEP--changes are of different kind and incidence. A typical change of the potential for the infantile head trauma cannot be found. The regression of the traumatically conditioned BAEP--changes begins during the first days after trauma and it is finished within 6 months in half of the children. In the particular case changes can be detected after two years yet.

Adolescent

[Modification of blood coagulation by the anti-arrhythmia drug prajmalium bitartrate in vivo].

We studied the effects of prajmaliumbitartrate (PBT, Neo-Gilurytmal, Giulini Pharma, Hannover, FRG), an antiarrhythmic drug on some parameters of blood coagulation in patients. PBT, 20 mg given three times a day, significantly prolonged template bleeding time and ex vivo thrombus formation time in a modified Chandler's loop. Ex vivo platelet aggregation using different agonists and tests of the plasmatic coagulation system remained unchanged.

Ajmaline

[The effect of the antiarrhythmic, prajmalium bitartrate, on human thrombocyte function].

Studies of the in vitro effects of the antiarrhythmic drug prajmalium bitartrate (PBT, Neo-Gilurytmal) showed inhibitory effects on platelet aggregation and thromboxane production. PBT inhibited the primary and secondary phases of aggregation induced by adrenaline (epinephrine) or adenosine diphosphate (ADP). Platelet aggregation stimulated with collagen, platelet activating factor (PAF), and the thromboxane mimetic 9,11-azo-prostaglandin H2 (U 44064) was inhibited. The secondary phase of aggregation induced by ristocetin and aggregation caused by arachidonic acid (AA) were inhibited in samples from some donors (responders) but not in others (nonresponders). Platelet aggregation by the ionophore calcimycine (A 23187) was not inhibited, but small doses of calcimycine abolished the PBT-induced inhibition of aggregation caused by ADP. Thromboxane production of platelets with collagen of ADP was inhibited by higher concentrations of PBT, whereas AA-induced thromboxane synthesis remained unchanged. The observed antiplatelet activities of PBT are thought to result from calcium and sodium channel blocking properties of the drug.

Ajmaline

[Effect of o-phosphate on the myoglobin spectrum].

o-Phosphate causes myoglobin solutions to change colour from brown to reddish-brown. The spectrum of myoglobin in the presence of o-phosphate is characterized by two peaks, one at 540 nm and the other at 575 nm and also by a shift in the Soret band at 409 nm to 420 nm.

Hemeproteins

Localized thyroid plasmacytoma.

Two cases of localized thyroid plasmacytoma are described and the literature is reviewed. In most cases the tumors arise in thyroid glands with lymphocytic thyroiditis. Thyroidectomy with regional lymph node biopsy seems to be the initial treatment of choice. Postoperative irradiation appears to be indicated in cases with residual thyroid tissue remaining and in those with documented regional nodal involvement.

Aged

Anatomo-radiological study of a case of post-radiotherapeutic osteolysis of the hip.

Anatomo-radiological study of a case of osteolysis of the femoral head and neck in a 56-year old male who had recieved, 22 years earlier, an intense radiotherapeutic treatment for a soft tissue tumour of the corresponding hip region. The treatment is considered as being the main etiological factor responsible for the bone lesions. The latter seems to have been favored by an indolent joint due to a thoracic cordotomy for post-irradiation pains; it may have been prepared by a secondary osteodystrophy which preceded the radiotherapy and seems due to two previous surgical excisions.

Bone Resorption

[Salivary electrolytes, digitalis glycosides and cardiac insufficiency].

In a group of 29 patients treated with digoxin for cardiac failure, only 16 showed increased calcium and potassium concentrations in saliva. There was no correlation in the 29 patients between serum digoxin levels and concentrations of salivary electrolytes. On the other hand, in 4 normal subjects treated with digoxin no change in salivary electrolytes was noted. It is concluded that modifications in salivary electrolytes seen in patients with cardiac failure treated with digitalis are not due to this drug. However, a retrospective clinical study showed a good correlation between clinical signs of cardiac failure and increased levels of salivary calcium, potassium and CaX Kproduct. It is suggested that this phenomenon is due to the well-known adrenergic stimulation in patients with cardiac failure.

Adult

The formation of glycosidic bonds in yeast glycoproteins. Intracellular localisation of the reactions.

Membranes of Saccharomyces cerevisiae were separated on urografin gradients. The specific activity of the light membranes (endoplasmic reticulum), the Golgi-like vesicles and the plasma membrane in transferring mannosyl residues from GDP-mannose to mannoproteins and to dolichyl monophosphate has been determined. The first mannose of the O-glycosidically linked manno-oligosaccharides is incorporated with the highest specific activity by the endoplasmic reticulum. The incorporation of the second to fourth mannosyl groups is catalysed with increasing activity also by the Golgi-like vesicles and the plasma membrane. The incorporation of mannosyl groups into weak alkali-stable positions (N-glycosidically linked chains) is carried out with almost the same specific activity by all three membrane fractions, however, dolichol-dependent and -independent steps could not be distinguished as yet. The results are discussed in terms of a sequential addition of sugar residues along the route of export of the mannoprotiens. The dolichol-dependent steps seem to occur on the endoplasmic reticulum and thus very early in the event.

Cell Membrane

Blastomatous tumors of the respiratory tract.

Two cases of blastomatous tumors of the respiratory tract are presented. The first is a pulmonary blastoma of an 81-year-old man, diagnosed as adenocarcinoma by cytologic examination, the cells being exfoliated from the large carcinomatous component. The patient died 1 year after manifestation of the symptoms. The second case is a tumor that developed in the nasopharynx of a 62-year-old man. This is the first reported case of a nasopharyngeal blastoma that presented a histology comparable to that seen in the pulmonary tumor. The presence of a hamartomatous benign mesenchymal component raises histogenetic considerations as to whether this was an independent part of an otherwise malignant tumor or whether it was induced by the malignant growth. Following incomplete surgical treatment and postoperative radiation, no recurrence was observed during the next 8 months.

Aged