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Biomedical subjects

P Theiss

Publications and source records attributed to P Theiss.

13 recordsLinked to original sources
PubMed2001

Clinical effectiveness of a potassium chloride containing chewing gum in the treatment of hypersensitive teeth.

Dental hypersensitivity has been observed in an increasing number of younger patients over the past few decades. The reasons for this include forced or false tooth-brushing techniques, and abrasions caused by bruxism or orthodontic procedures. The aim of the present study was to assess the possible benefits of a potassium chloride (KCl) containing chewing gum in dental hypersensitivity. The study population consisted of 59 selected university students (age: 25 +/- 4.4 years). Each subject suitable for entry into the study had more than 3 teeth sensitive to thermal stimulation (air stimulus range of 30-80 mm on a 100mm visual analogue scale (VAS), and showed signs of facial/cervical erosion, abrasion and/or gingival recession. Exclusion criteria were daily doses of medication, teeth with deep restorations, a gingival score of > 2, or periodontal surgery within the past 6 months. The total number of hypersensitive teeth was 217. Over a period of 3 weeks the subjects brushed with a non-desensitising toothpaste and, in addition, used the KCl chewing gum up to 6 times daily for 10 min on each occasion. This was followed by a period of 3 weeks of non-desensitising toothpaste use alone. The subjects were questioned on the severity of intraoral pain and asked to indicate the intensity of the pain on the VAS (baseline, 1, 3 and 6 weeks). Mean thermal sensitivity at baseline was 54.5 +/- 9 mm. There was a drop to 40.8 mm ( 1.9) after 1 week and to 28.6 mm (+/- 2) after 3 weeks. The reduction was statistically significant (p <0.001) at both measurement points. The mean rating increased to 29.1 mm after 6 weeks. The results of this study demonstrate that the daily use of a KCl containing chewing gum is a useful non-invasive method of reducing dental hypersensitivity over an extended period of time.

Adult↗
PubMed1997

Albert the Great's interpretation of neuropsychiatric symptoms in the context of scholastic psychology and physiology.

Albert the Great (ca. 1193-1280) serves as an example to show how the Latin West successfully integrated Greco-Arabian psychology with Galenic physiology. He divised a model of perceptive, cognitive and mnestic powers located in different areas of the "brain cells" and interacting with the immaterial and man-specific intellect. He managed to describe anmesis, epileptic seizures and psychotic states as results of disturbed brain fuction. Finally, further aspects of Scholastic theorizing on mental disorders are discussed.

Europe↗
PubMed1997

Localized frameshift mutation generates selective, high-frequency phase variation of a surface lipoprotein encoded by a mycoplasma ABC transporter operon.

The wall-less mycoplasmas have revealed unusual microbial strategies for adaptive variation of antigenic membrane proteins exposed during their surface colonization of host cells. In particular, high-frequency mutations affecting the expression of selected surface lipoproteins have been increasingly documented for this group of organisms. A novel manifestation of mutational phase variation is shown here to occur in Mycoplasma fermentans, a chronic human infectious agent and possible AIDS-associated pathogen. A putative ABC type transport operon encoding four gene products is identified. The 3' distal gene encoding P78, a known surface-exposed antigen and the proposed substrate-binding lipoprotein of the transporter, is subject to localized hypermutation in a short homopolymeric tract of adenine residues located in the N-terminal coding region of the mature product. High-frequency, reversible insertion/deletion frameshift mutations lead to selective phase variation in P78 expression, whereas the putative nucleotide-binding protein, P63, encoded by the most 5' gene of the operon, is continually expressed. Mutation-based phase variation in specific surface-exposed microbial transporter components may provide an adaptive advantage for immune evasion, while continued expression of other elements of the same transporter may preserve essential metabolic functions and confer alternative substrate specificity. These features could be critical in mycoplasmas, where limitations in both transcriptional regulators and transport systems may prevail. This study also documents that P63 contains an uncharacteristic hydrophobic sequence between predicted nucleotide binding motifs and displays an amphiphilic character in detergent fractionation. Both features are consistent with an evolutionary adaptation favoring integral association of this putative energy-transducing component with the single mycoplasma membrane.

ATP-Binding Cassette Transporters↗
PubMed1996

Antigenic topology of the P29 surface lipoprotein of Mycoplasma fermentans: differential display of epitopes results in high-frequency phase variation.

Antibodies to P29, a major lipid-modified surface protein of Mycoplasma fermentans, reveal phase variation of surface epitopes occurring with high frequency in clonal lineages of the organism. This occurs despite continuous expression of the entire epitope-bearing P29 product (detected by Western immunoblotting) and contrasts with phase variation of other surface antigens mediated by differential expression of proteins. To understand the structure and antigenic topology of P29, the single-copy p29 gene from strain PG18 was cloned and sequenced. The gene encodes a prolipoprotein containing a signal sequence predicted to be modified with lipid and cleaved at the N-terminal Cys-1 residue of the mature P29 lipoprotein. The remaining 218-residue hydrophilic sequence of P29 is predicted to be located external to the single plasma membrane. Additional Cys residues at positions 91 and 128 in the mature protein were shown to form a 36-residue disulfide loop by selectively labeling sulfhydryl groups that were liberated only after chemical reduction of monomeric P29. Two nearly identical charged amino acid sequences occurred in P29, within the disulfide loop and upstream of this structure. Two distinct epitopes binding different monoclonal antibodies were associated with opposite ends of the P29 protein, by mapping products expressed in Escherichia coli from PCR-generated 3' deletion mutations of the p29 gene. Each monoclonal antibody detected high-frequency and noncoordinate changes in accessibility of the corresponding epitopes in colony immunoblots of clonal variants, yet sequencing of the p29 gene from these variants and analysis of disulfide bonds revealed no associated changes in the primary sequence or disulfide loop structure of P29. These results suggest that P29 surface epitope variation may involve masking of selected regions of P29, possibly by other surface components undergoing phase variation by differential expression. Differential masking may be an important mechanism for altering the antigenic or functional surface topology of this mycoplasma and other wall-less mycoplasmas.

Amino Acid Sequence↗
PubMed1994

Vision and cognition in the natural philosophy of Albert the Great (Albertus Magnus).

Albert the Great (Albertus Magnus, ca. 1197-1280) descended from a nobleman's family in Upper Suebia and studied natural philosophy and theology at the University of Padova, where he joined the Dominican order. Confronted with Aristotelian thought mainly in its Arabic modification (Avicenna, Al-Farabi, Averroes, Alhazen, Costa ben Luca and others) from his days in Padova, he elaborated in several books on the principles of natural philosophy, biology, brain and sense functions and psychology in addition to his theological and exegetic works. His observations and concepts on vision are discussed in detail. It is pointed out that Albert discovered some phenomena of vision not before known such as vestibular nystagmus and rod monochromacy, i.e. total colour blindness accompanied by photophobia. Based on clinical observations Albert also postulated a decussation of the optic nerve fibres at the optic chiasm. Albert's concept of higher order cognitive function is discussed and some of his explanations of dreams and neuropsychiatric disease on the basis of his cognitive model are mentioned. Albert's thoughts on vision and other sense perceptions, higher brain functions and cognition are considered as progressive elaborations of Galenic concepts as adapted by some Patristic theologians and the Arabic natural scientists and philosophers of the 9th-11th century.

Cognition↗
PubMed1976

AMT catalepsy and hypokinesia: interaction with morphine and cocaine.

Acute morphine induced a dose-dependent hypokinesia and rigidity, but only mild and non-dose-dependent catalepsy. AMT, injected 1/2 h after morphine, slightly potentiated catalepsy but not hypokinesia during 3 h after morphine; in contrast, rigidity was decreased. The behavioral changes induced by AMT were accelerated in onset and reached their usual development, although AMT toxicity and hypothermia were completely antagonized; thus, it would appear that AMT hypokinesia/catalepsy are not the consequence of toxicity. When morphine was injected 4 h after AMT, a mutual potentiation of the two drugs on hypokinesia and catalepsy was observed, although previous biochemical measurements had shown no effect of morphine on CA depletion under these conditions. Rigidity appeared to be antagonized. After 17 days of repeated injections, morphine no longer elicited hypokinesia and catalepsy, but no cross-tolerance developed to the AMT behavioral changes. A similar lack of cross-tolerance to the effects of AMT or haloperidol was observed when morphine tolerance was induced by pellet implantation. Catalepsy and hypokinesia developed in a much more pronounced way after two large i.p. doses than after small, multiple administration of AMT; this difference was accompanied by a significantly lower concentration of brain DA, but not NA in the former group. The hyperthermic response observed after a 40 mg/kg s.c. injection of morphine was reversed to hypothermia when the same dose was given 4 or 10 h after CA synthesis inhibition. Cocaine strongly antagonized AMT hypokinesia and catalepsy when given 8 1/2 h after AMT, and, although to a lesser extent, even when injected 12 1/2 h after AMT.

Animals↗
PubMed1975

The effect of yohimbine on the turnover of brain catecholamines and serotonin.

Yohimbine moderately increased the depletion of brain dopamine (DA) after alpha-methyl-p-tyrosine (AMT) only when the two drugs were given at the same time; the baseline concentration of brain homovanillic acid (HVA) and its accumulation after probenecid were strongly increased by yohimbine. Yohimbine markedly decreased the concentration of brain noradrenaline (NA), both when given alone and before or at the same time as AMT; when it was given at an increasing interval after AMT, the effect became progressively smaller. The baseline concentration of brain 3-methyoxy-4-hydroxyphenylethyleneglycol sulphate and its accumulation after probenecid were increased by yohimbine; this effect was not as marked as that on HVA and was proportional to the quantity of NA depleted in the Amt method. The accumulation of brain k-hydroxyindoleacetic acid after probenecid was decreased by yohimbine pretreatment.

Animals↗
PubMed1975

Effects of morphine on the turnover of brain catecholamines and serotonin in rats-acute morphine administration.

Morphine increased the rate of brain dopamine (DA) depletion when given before alpha-methyl-p-tyrosine (AMT) or alpha-propyl-dopacetamide, but not when given after AMT. No effect of morphine was found on the rate of depletion of brain noradrenaline (NA) or serotonin (5-HT) after the two synthesis inhibitors. The accumulation of homovanillic acid and 5-hydroxy-indoleacetic acid induced by probenecid was significantly increased by morphine pretreatment, whereas the accumulation of 3-methoxy-4-hydroxy-phenylglycol sulphate was not changed. These findings can be best explained by the hypothesis that morphine increases the non-functional intraneuronal catabolism of newly synthesized DA and 5-HT, without much effect on the monoamines already taken up in the synaptic vesicles. NA turnover does not seem to be changed by acute morphine administration.

3-Methoxy-4-hydroxyphenylethanol↗
PubMed1975

Effects of morphine on the turnover of brain catecholamines and serotonin in rats-chronic morphine administration.

The turnover of brain monoamine was studied in rats in which different degrees of tolerance to and dependence on morphine were induced by pellet implantation. The degree of tolerance to morphine was assessed by measuring the increase in effective dose for an antinociceptive effect (vocalization test). The rate of depletion of brain dopamine (DA) and serotonin (5-ht) after alpha-methyl-p-tyrosine (AMT) or alpha-propyl-dopacetamide (dopacetamide) was not changed by chronic morphine treatment. In contrast, the accumulation of brain homovanillic acid HVA) and 5-hydroxyindoleacetic acid (5-HIAA) after probenecid was significantly increased, but there was no correlation between the biochemical changes and the degree of tolerance/dependence of the animals; at a very high degree of dependence 5-HIAA accumulation even became normal. In rats in which smaller amounts of morphine were repeatedly injected every 8 hr for 1 week the increased accumulation of HVA and 5-HIAA persisted in spite of complete tolerance to the antinociceptive effect. The rate of depletion of brain noradrenaline (NA) after AMT or dopacetamide was not changed and the accumulation of brain 3-methoxy-4-hydroxy-phenylglycol sulphate (MHPG-SO4) after probenecid was not affected in most chronic morphine groups. In the group with the highest degree of tolerance/dependence NA depletion after AMT was even retarded. The results suggest that chronic morphine treatment increases the synthesis and the intraneuronal destruction of newly synthesized DA and 5-HT without changing the rate of functional utilization of the monoamines. It is unlikely that the changes in monoamine metabolism are causally related to processes leading to morphine tolerance/dependence.

3-Methoxy-4-hydroxyphenylethanol↗