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Biomedical subjects

M Maurer

Publications and source records attributed to M Maurer.

At least 91 records · Page 5Linked to original sources
PubMed1994

Melanogenesis during the anagen-catagen-telogen transformation of the murine hair cycle.

Melanin synthesis of follicular melanocytes is strictly coupled to the growth stage of the hair cycle (anagen), ceases during follicle regression (catagen), and is absent throughout the resting stage (telogen). Having previously characterized the expression and activity of melanogenesis-related proteins during the telogen-anagen transition of the murine hair cycle (JID 96:172, 1991), we here report a biophysical and biochemical analysis of follicular melanogenesis during the anagen-catagen-telogen transformation of the C57 BL-6 mouse hair cycle. Tyrosinase activity and concentration as well as dopachrome tautomerase activity were compared with melanin synthesis, as measured by electron paramagnetic resonance spectroscopy (EPR). The visible changes in skin color and the histologically appreciable switch-off of melanin formation during the anagen-catagen transformation were accompanied by a steep decline in 1) the melanin-associated EPR signal of full-thickness mouse skin, 2) tyrosinase and dopachrome tautomerase activities, and 3) the skin concentration of 80-85-kD melanogenesis related protein and 66-68-kD tyrosinase protein. Telogen skin displayed a minimum of the EPR amplitude as well as of tyrosinase and dopachrome tautomerase activity detected. By EPR, only eumelanin was identified during all hair cycle stages. The gradual switch-off of melanogenesis during anagen VI started with an unexpectedly early decline of the EPR melanin signal, followed by dopachrome tautomerase activity and the concentration of 80-85-kD melanogenesis related protein. The initiation of catagen was characterized by a significant and rapid decrease in activity and concentration of tyrosinase, and was accompanied by a second drop in dopachrome tautomerase activity. Together, these biochemical and biophysical parameters of follicular melanogenesis serve as novel and differential markers for the imminent termination of anagen and the development of catagen. They also show that the switch-off of melanogenesis during the anagen-catagen-telogen transition is a stochastic process commencing already in mid anagen VI.

Animals↗
PubMed1994

Murine skin as a target for melatonin bioregulation.

Specific binding sites for 3H-melatonin were detected in membrane fractions prepared from C57 BL-6 mouse skin, and were localized to the epidermis and the epithelial bulb of the hair follicle by in situ autoradiography. In skin organ culture, melatonin stimulated DNA synthesis by the epidermal keratinocytes at concentration 0.1-10 nM, while at > or = 1 microM it inhibited tyrosinase activity. We concluded that murine skin is a target for melatonin bioregulation.

Animals↗
PubMed1993

A randomized double-blind study of fluoxetine versus placebo in the treatment of dysthymia.

OBJECTIVE: The purpose of this study was to assess the efficacy of fluoxetine, a selective serotonergic antidepressant, in the treatment of dysthymia. METHOD: Thirty-five patients who met criteria for dysthymia, but not major depression, began randomized, double-blind 8-week trials of fluoxetine or placebo. RESULTS: Of 32 patients who completed the study, 10 (62.5%) of the 16 patients given fluoxetine and three (18.8%) of the 16 given placebo responded to treatment. Response was defined as 1) 50% or greater decrease in Hamilton Rating Scale for Depression score and 2) a score of 1 or 2 on the Clinical Global Impression (CGI) improvement subscale. Fluoxetine subjects showed significantly greater improvement at week 8 than placebo subjects on the Hamilton depression and CGI scales, but not on the Hopkins Symptom Check-list (58-item) or the Cornell Dysthymia Rating Scale. CONCLUSIONS: When compared to placebo, fluoxetine showed short-term effectiveness in treating dysthymic symptoms.

Adult↗
PubMed1992

CENP-C, an autoantigen in scleroderma, is a component of the human inner kinetochore plate.

We have isolated and characterized a set of overlapping cDNA clones that encode the human centromere autoantigen centromere protein C (CENP-C). The identity of these clones has been established using several criteria. First, they were shown to encode a polypeptide that migrates at the expected position for CENP-C on SDS-polyacrylamide gel electrophoresis. Second, we have demonstrated that this polypeptide shares at least two epitopes with human CENP-C. Polyclonal antibodies were raised to fusion proteins encoded by nonoverlapping regions of the cDNA clones. These antibodies were shown to recognize a protein at a position appropriate for CENP-C on immunoblots of human chromosomal proteins. In addition, we used indirect immunofluorescence to demonstrate that these antibodies recognize centromeres of HeLa chromosomes in the expected pattern for CENP-C. Localization of CENP-C by immunoelectron microscopy reveals that this protein is a component of the inner kinetochore plate.

Amino Acid Sequence↗
PubMed1992

[The value of imaging techniques in the diagnosis of non-specific abdominal pain in young patients].

In a retrospective study the use of imaging modalities in the diagnosis of non-specific abdominal pain in patients under 31 years was evaluated. 253 patients with primarily non-specific abdominal complaints were analysed. For further investigation one of the following methods had to be applied: abdominal sonography and/or upper gastrointestinal tract roentgenograms and/or enteroclysis and/or barium enema. In 66% (167/253) of all cases abdominal pain remained non-specific. Clinical history and physical examination led to the final diagnosis in 66/86 (76.7%) of patients with pathologic findings. 21/561 (3.7%) radiographic examinations revealed abnormalities of clinical importance. In 10/253 (4%) patients the final diagnosis could be established only with the help of radiologic and/or endoscopic examinations. The low efficacy of conventional radiology justifies the demand for a stricter indication in the young patient suffering from non-specific abdominal pain.

Abdominal Pain↗
PubMed1991

Improved neonatal survival following multiple doses of bovine surfactant in very premature neonates at risk for respiratory distress syndrome.

To determine whether multiple doses of bovine surfactant would improve neonatal mortality in very premature neonates, we conducted two multicenter controlled trials under identical protocols; the results were combined for analysis. Four hundred and thirty neonates born between 23 and 29 weeks gestation and weighing 600 to 1250 g at birth were assigned randomly at birth to receive either 100 mg of phospholipids/kg of Survanta, a modified bovine surfactant (n = 210), or a sham air placebo (n = 220) within 15 minutes of birth. Neonates who developed respiratory distress syndrome and required mechanical ventilation with at least 30% oxygen could be given up to three more doses in the first 48 hours after birth. Dosing was performed by investigators not involved in the clinical care of the neonates; nursery staff were kept blinded as to the treatment assignment. Cause of death was determined by a panel of three independent, board-certified neonatologists after blindly reviewing case report forms and autopsy reports. Fewer Survanta-treated neonates died of any cause (11.4% vs 18.8%, P = .031), died of respiratory distress syndrome (1.9% vs 15.6%, P less than .001), and either died or developed bronchopulmonary dysplasia due to respiratory distress syndrome (39.5% vs 49.1%, P = .044). The incidence of respiratory distress syndrome was also lower in Survanta-treated neonates (28.0% vs 56.9%, P less than .001), and the Survanta-treated neonates' oxygenation and ventilatory status were improved significantly at 72 hours. Survanta-treated neonates were also at lowered risk of developing pulmonary interstitial emphysema (23.3% vs 36.9%, P = .002) and other forms of pulmonary air leaks (9.6% vs 20.8%, P .002).(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Inhalation↗
PubMed1990

Delta-9-tetrahydrocannabinol shows antispastic and analgesic effects in a single case double-blind trial.

A double-blind study was performed comparing 5 mg delta-9-tetrahydrocannabinol (THC) p.o., 50 mg codeine p.o., and placebo in a patient with spasticity and pain due to spinal cord injury. The three conditions were applied 18 times each in a randomized and balanced order. Delta-9-THC and codeine both had an analgesic effect in comparison with placebo. Only delta-9-THC showed a significant beneficial effect on spasticity. In the dosage of THC used no altered consciousness occurred.

Adult↗
PubMed1990

Intrastriatal infusions of ascorbate antagonize the behavioral response to amphetamine.

Compared to saline, bilateral infusions of ascorbate (AA) into the neostriatum of freely moving rats attenuated rearing, head bobbing, and sniffing at various times after systemic amphetamine administration. Comparable AA infusions into overlying cerebral cortex failed to alter the amphetamine behavioral response. Intrastriatal AA also enhanced the ability of haloperidol to antagonize amphetamine-induced forepaw shuffling and locomotion. Voltammetric measurements in separate animals revealed a linear increase in neostriatal AA that remained within reasonable physiological limits over the course of the AA infusion. Thus, endogenous AA may modulate behavior via mechanisms intrinsic to the neostriatum.

Administration, Intranasal↗
PubMed1989

ELISA with enzyme amplification for sensitive detection of staphylococcal enterotoxins in food.

A highly sensitive amplified ELISA in microtitre plates for the detection of staphylococcal enterotoxins compared favourably with a commercially available kit. The amplified ELISA demonstrated a reduced effect of the food sample matrix and an ease of handling. Using the amplified ELISA, the influence of different parameters (pH, time, temperature, re-extraction, concentration procedure) on the recovery efficiency and assay reliability was tested on foods implicated in food poisoning outbreaks as well as on spiked foods containing low levels of enterotoxins.

Enterotoxins↗