A study of some current methods for assessment of nasal histamine reactivity

The aim of this study was to investigate the reactivity of the nasal mucosa of patients with pollen allergy compared to healthy controls, when challenged with histamine outside the pollen season. Assessments were made with symptom score, acoustic rhinometry, nasal peak expiratory and inspiratory flow (NPEF and NPIF) and rhinomanometry in order to find the most sensitive method for the purpose. Twenty-one patients with seasonal allergic rhinitis and 20 healthy controls were challenged with histamine dihydrochloride in increasing concentrations (0.01, 0.1, 1.0 mg/ml) locally in the nose. Our results show no difference in mucosal reactivity between the patients and controls regardless of the method used. When comparing the methods we find that NPIF and NPEF are more sensitive to mucosal changes than the other methods we have studied.     

Peel bond strength of resilient liner modified by the addition of antimicrobial agents to denture base acrylic resin

In order to prolong the clinical longevity of resilient denture relining materials and reduce plaque accumulation, incorporation of antimicrobial agents into these materials has been proposed. However, this addition may affect their properties.

Objective

This study evaluated the effect of the addition of antimicrobial agents into one soft liner (Soft Confort, Dencril) on its peel bond strength to one denture base (QC 20, Dentsply).

Material and Methods

Acrylic specimens (n=9) were made (75x10x3 mm) and stored in distilled water at 37ºC for 48 h. The drug powder concentrations (nystatin 500,000U - G2; nystatin 1,000,000U - G3; miconazole 125 mg - G4; miconazole 250 mg - G5; ketoconazole 100 mg - G6; ketoconazole 200 mg - G7; chlorhexidine diacetate 5% - G8; and 10% chlorhexidine diacetate - G9) were blended with the soft liner powder before the addition of the soft liner liquid. A group (G1) without any drug incorporation was used as control. Specimens (n=9) (75x10x6 mm) were plasticized according to the manufacturers'' instructions and stored in distilled water at 37ºC for 24 h. Relined specimens were then submitted to a 180-degree peel test at a crosshead speed of 10 mm/min. Data (MPa) were analyzed by analysis of variance (α=0.05) and the failure modes were visually classified.

Results

No significant difference was found among experimental groups (p=0.148). Cohesive failure located within the resilient material was predominantly observed in all tested groups.

Conclusions

Peel bond strength between the denture base and the modified soft liner was not affected by the addition of antimicrobial agents.     

Lability of N-alkylated peptides towards TFA cleavage

Trifluoroacetic acid (TFA) is a common reagent in both solid-phase and solution peptide synthesis. It is used for the deprotection and/or cleavage of the synthesized peptide from the resin. The use of TFA under these standardized conditions is thought to be sufficiently mild, thereby preventing degradation of the desired product. However, peptides of the general structure R¹-(N-alkyl X₁)-X₂-R² are hydrolyzed by standard TFA solid-phase peptide synthesis (SPPS) cleavage/deprotection conditions providing fragments R¹-(N-alkyl X₁)-OH and H-X₂-R². The fragmentation is observed during a TFA cleavage both from the resin and in solution. The hydrolysis is proposed to proceed via an oxazolone-like intermediate in which equilibration of the chiral center of the N-alkylated residue occurs. This mechanism is supported by H/D exchange as observed by MS and NMR in conjunction with HPLC. © Munksgaard 1996.     

Comparison of four continuously administered progestogen plus oestradiol combinations for climacteric complaints

Summary. Sixty women with climacteric complaints who had not menstruated for at least 1 year were randomly allocated to receive one of four hormonal replacement regimens. All four formulations were administered daily and continuously and each contained 2 mg of micronized oestradiol-17β in combination with either norethisterone acetate 1 mg (group A) or 0·5 mg (group B) or megestrol acetate 5 mg (group C) or 2·5 mg (group D). The clinical efficacy was the same although the alleviation of vasomotor symptoms was somewhat slower in those women receiving preparation A. The endometrium was atrophied in nearly all biopsies. Irregular uterine bleeding was almost entirely confined to the earlier phase of the study and was substantially less with the formulation containing 1 mg norethisterone acetate. It is concluded that a continuous oestradiol-progestogen combination can be used for longterm treatment of climacteric complaints in postmenopausal women and that after 4 months the clinical efficacy is the same irrespective of the type and dose of progestogen administered.     

Visceral Leishmaniasis Complicating Polycythemia Vera

Abstract. A case of visceral leishmaniasis is presented, where a pre-existing polycythemia vera obscured signs of the infection. Visceral leishmaniasis is a life-threatening but curable protozoan infection of the reticuloendothelial system. We wish to report a case where symptoms and signs were obscured by a preexisting hematologic disease, polycythemia vera.     

MOLECULAR ACTIONS OF RACEMIC KETAMINE ON HUMAN CNS SODIUM CHANNELS

In search of a molecular site and mechanism of action for anaesthetics,we have examined the effects of racemic ketamine on single humanCNS sodium channels with the new planar lipid bilayer technique.In the dose range studied (0.05–9.2 mmol litre^–1)ketamine depressed in a dose-dependent manner two major functionsof the sodium channel, by reducing the fractional open timein a voltage-independent manner (ED₅₀ 1.1 mmol litre^–1;maximal conductance block 71 %) and by interfering with thevoltage-dependent, steady-state activation. These actions occurredat concentrations which were greater than those used clinicallyin general anaesthesia (up to 0.02 mmol litre^–1), thereforethey reflect local rather than general anaesthetic effects whichmay be related to the hydrophobic properties of ketamine. Incomparison with two other i.v. anaesthetic agents, pentobarbitoneand propofol, racemic ketamine behaves differently at both themolecular and the clinical level. ^*Present address: Institut fur Anasthesiologie der RheinischenFriedrich-Wilhelms-Universitfit Bonn, Sigmund-Freud-Str. 25,D-W 5300 Bonn 1, Federal Republic of Germany