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Biomedical subjects

O Keller

Publications and source records attributed to O Keller.

At least 37 records · Page 2Linked to original sources
PubMed1984

Monoclonal antibody against a cryptic carbohydrate antigen of murine and human lymphocytes. I. Antigen expression in non-cryptic or unsubstituted form on certain murine lymphomas, on a spontaneous murine mammary carcinoma, and on several human adenocarcinomas.

This paper describes an IgM monoclonal antibody (49H.8) which was produced following immunization of BALB/c mice with human neuraminidase-treated erythrocytes (NE-RBC). 49H.8 reacts with NE-RBC, neuraminidase-treated T lymphocytes (NE-T) and NE B lymphocytes of both human and murine origin. Little or no reactivity with untreated T or B cells could be detected. Thus the 49H.8 antigen is "cryptic" in most normal lymphocytes of both humans and mice. In contrast, the 49H.8 antigen was detected in non-cryptic or unsubstituted form on many non-treated murine lymphomas of both B- and T-cell origin, on the spontaneous murine mammary carcinoma, TA3-HA and on several human adenocarcinomas. The 49H.8 antigen appears to be related to the previously described 49H.24 antigen as shown by sugar inhibition experiments. 49H.24 reacts most strongly with the synthetic disaccharide (betaGa1 (I leads to 3)alpha Ga1NAc) but not at all with beta Ga1(I leads to 3)beta Ga1Nac. 49H.24 does not react with any of the murine or human tumors tested. 49H.8 reacts with both the alpha and beta forms of the disaccharide but reacts most strongly with phenyl-beta-galactoside-containing compounds. In contrast, phenyl-alpha-galactoside-containing compounds produced no reaction. The natural determinant detected by this antibody was not determined but various possibilities are considered. 49H.8 was used to detect antigen apparently shed from growing TA3-Ha cells into the serum and ascites of tumor-bearing mice. These observations suggest that the 49H.8 monoclonal antibody will be valuable as a specific reagent for a common tumor-associated antigen shared by certain murine and human tumors, and as a means of assaying shed tumor antigen in circulation as in the TA3-Ha mammary adenocarcinoma model.

Adenocarcinoma↗
PubMed1983

[Social consequences of Crohn's disease].

Impairment of social function was measured by questionnaire in 270 patients with Crohn's disease. In about half of them, the disease had had its onset below the age of 20 years. In 10%, schooling or job training was delayed or even had to be abandoned. Ten percent of the patients were forced to change their occupation because of the disease. 23.5% of the patients stated that their illness had prevented them from having whole-day jobs. Ten percent had temporary or permanent pensions; 3.8% were unemployed. 43.7% of patients stated that the relation to their family and (or) partner was impaired by the disease; in 36.4% the disease had interfered with leisure time activities. The results show that Crohn's disease has social effects which in the individual case can be very serious; they correlate with the duration and severity of the disease. Nonetheless, the majority of patients succeeds in mastering their chosen training and occupation and leading an active life.

Adolescent↗
PubMed1981

Projection of tooth pulp afferents to the brainstem and to the cortex in the cat.

The projection of tooth pulp afferents in the spinal trigeminal nucleus (N.V.sp.) and the effect of dorsolateral medullotomy on cortical potentials evoked by electrical stimulation of Adelta tooth pulp nerve fibres were studied in cats. It was confirmed that antidromic responses were recorded in the tooth pulp nerve to stimulation of the ipsilateral but not the contralateral N.V.sp.[11]. Dorsolateral medullotomy at the level of the obex did not alter the cortical potentials induced by single pulses applied to the tooth pulp. It is concluded that Adelta tooth pulp afferents project exclusively to the ipsilateral trigeminal nucleus and that the impulse transmission to the cortex persists after transection of the pars caudalis of the N.V.sp.

Afferent Pathways↗
PubMed1981

Synthesis of 2-(trimethylsilyl)ethyloxycarbonylamino acids and their use in peptide chemistry.

2-(Trimethylsilyl)ethyl-4-nitrophenyl carbonate has been prepared as a new reagent for the introduction of the 2-(trimethylsilyl)ethyloxycarbonyl group into amino acids or amino acid derivatives. The resulting N alpha-protected amino acids were found to represent suitable intermediates for the synthesis of peptides. The amino-protecting group proved to be stable under the usual conditions of peptide synthesis and readily cleaved in selective conditions via fluoride ion-mediated fragmentation.

Amino Acids↗
PubMed1979

Low impedance coaxial K+ selective microelectrodes.

A procedure for preparing coaxial K+ selective microelectrodes with a low longitudinal resistance (Re) of the liquid ion exchanger selective barrel is described. The low resistance was attained by inserting another microelectrode filled with 0.5 mol . 1-1 KCl into the ion-exchanger column (Corning 477317). The lower longitudinal resistance decreases the noise level and consequently increases the resolving power five times. This modification makes it possible to measure small and rapid K+ concentration changes.

Electrophysiology↗
PubMed1979

[Not Available].

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History of Pharmacy↗
PubMed1977

Tooth pulp stimulation as an unconditioned stimulus in defensive instrumental conditioning.

In an experiment performed on five cats, stable escape and avoidance reflexes in a bar-pressing situation were established using tooth pulp electric stimulation as the unconditioned stimulus. The influence of changes in parameters of the unconditioned stimulus (current intensity, single pulse and train durations, frequency of pulses and rate of train presentations) on unconditioned and instrumental responses was analysed in three additional subjects. Among other relationships the dependence of the threshold of bar press responses on the amount of charge in a single pulse was determined.

Animals↗
PubMed1977

[Postsynaptic potentials of trigeminal nerve nucleus motor neurons evoked by stimulation of the dental pulp in cats].

PSPS of the digastric and masseter motoneurons evoked by stimulation of the upper canine pulp of the ipsi- and contralateral side were studied in the nembutal-chloralose anesthetized cats. Stimulation by single volleys of tooth pulp evoked EPSP and action potentials in digastric motoneurons (latency for ipsilateral pulp was 4.0-5.5 ms, for contralateral--7.0-8.0 ms) and IPSP in masseter motoneurons (latency for ipsilateral pulp was 3.5-4.2 ms, for contralateral--3.8-5.5 ms). All PSPS were polysynaptic.

Animals↗
PubMed1977

Spinal trigeminal tractotomy and nociceptive reactions evoked by tooth pulp stimulation in the cat.

The effect of transection of the descending root of the spinal trigeminal tract on nociceptive and aversive reactions evoked by stimulation of the tooth pulp nerve was studied in cats. The transection was performed 1-1.5 mm caudally to the obex. 1. The nociceptive reaction, characterized by wide opening of the jaw, dorsiflexion and rotation of the head and by signs of affective behaviour, remained unchanged after transection of the descending root of the trigeminal nerve (n = 6). 2. The instrumental escape reaction was elaborated in three cats before transection of the descending root of the trigeminal nerve and in three cats after transection. The escape reaction was retained after transection of the descending root and the speed of learning to escape the tooth pulp stimulation did not significantly differ in these two groups of animals. 3. It is to be concluded that the transection of the descending root of the spinal trigeminal tract in the cat does not result in dental analgesia.

Animals↗
PubMed1976

[Fluorescence serologic studies for the detection of Trichinella spiralis].

Attempts were made to find out, if Trichinella (Tr.) spiralis could be detected by means of immunofluorescence. An applicable Trichinella antigen was prepared by applying pepsin digestion to trichinous muscular tissue of experimentally infected guinea pig. Different quantities of Trichinae were orally administered to guinea pig and rabbit, and even parenteral infection of rabbit was attempted, with the view to obtain immune sera. Oral infection was followed by the occurrence of antibody titres, between the tenth day from infection and the sixtieth day, when the experiment was disrupted. Highest antibody titres were established in the fourth through sixth weeks after infection. Titres in excess to 1:64 could not be recorded by means of indirect immunofluorescence. No antibody were detected by fluorescence serology after parenteral immunisation. The detection of Trichinella spiralis by fluorescence microscopy was somewhat problematic. When the preparations were evaluated, some secondary fluorescence was observed. It had been caused by remnants of undigested muscular fibrils, contaminants, and cell detritus not removable by the authors' method of preparation and, therefore, also recorded. That secondary fluorescence, however, was eliminated by secondary staining, using methylen blue. Hence, fluorescence should not pose any obstacle to automatic reading of the reaction. Some five or six hours were required to detect by means of indirect immunofluorescence Trichinella antigen as extracted from test animals. Yet, in practice carcass processing would go on in that time. The above results, consequently, appear to suggest that for detection of Trichinella spiralis immunofluorescence cannot even replace trichinoscopy under the condition that the time of antigen preparation was shortened.

Animals↗