PubMed Health⌕ Search

Biomedical subjects

M Kirjavainen

Publications and source records attributed to M Kirjavainen.

10 recordsLinked to original sources
PubMed2001

Vitamin C enhances differentiation of a continuous keratinocyte cell line (REK) into epidermis with normal stratum corneum ultrastructure and functional permeability barrier.

A continuous rat epidermal cell line (rat epidermal keratinocyte; REK) formed a morphologically well-organized epidermis in the absence of feeder cells when grown for 3 weeks on a collagen gel in culture inserts at an air-liquid interface, and developed a permeability barrier resembling that of human skin. By 2 weeks, an orthokeratinized epidermis evolved with the suprabasal layers exhibiting the differentiation markers keratin 10, involucrin, and filaggrin. Granular cells with keratohyalin granules and lamellar bodies, and corneocytes with cornified envelopes and tightly packed keratin filaments were present. Morphologically, vitamin C supplementation of the culture further enhanced the normal wavy pattern of the stratum corneum, the number of keratohyalin granules present, and the quantity and organization of intercellular lipid lamellae in the interstices of the stratum corneum. The morphological enhancements observed with vitamin C correlated with improved epidermal barrier function, as indicated by reduction of the permeation rates of tritiated corticosterone and mannitol, and transepidermal water loss, with values close to those of human skin. Moreover, filaggrin mRNA was increased by vitamin C, and western blots confirmed higher levels of profilaggrin and filaggrin, suggesting that vitamin C also influences keratinocyte differentiation in aspects other than the synthesis and organization of barrier lipids. The unique REK cell line in organotypic culture thus provides an easily maintained and reproducible model for studies on epidermal differentiation and transepidermal permeation.

Animals↗
PubMed2000

Influence of lipids on the mannitol flux during transdermal iontophoresis in vitro.

The aim of the present study was to evaluate the influence of the lipids EPC (L-alpha-phosphatidylcholine, egg lecithin), DSPC (distearoylphosphatidylcholine), and SA (stearylamine) on the iontophoretic mannitol transport through human skin in vitro. The skin was pretreated with 1 mM lipid suspension with ethanol (32%) for 24 h prior to the iontophoretic experiment with mannitol. In addition, the penetration of fluorescent lipids into the epidermis during the pretreatment was studied by confocal laser scanning microscopy (CLSM). The results of the present study show that pretreatment of the skin with zwitterionic EPC increases the iontophoretic transdermal mannitol flux about three-fold compared to iontophoretic control without pretreatment. However, skin pretreatment with another zwitterionic phospholipid, DSPC, did not influence the iontophoretic flux of mannitol. In contrast, pretreatment of the skin with cationic SA decreased the iontophoretic mannitol flow from the anode. It is concluded that EPC works as a penetration enhancer further increasing the transdermal mannitol flux during iontophoresis. In contrast, the cationic stearylamine changes the charge of the skin, thus leading to decreased electroosmosis and decreased mannitol flux. Hence, the effects of stearylamine are assumed to be mediated by the alterations in the charge of the stratum corneum structures, while EPC is suggested to decrease the permeability barrier of the skin.

Administration, Cutaneous↗
PubMed2000

Orthopedic cervical headgear with an expanded inner bow in class II correction.

Forty consecutively referred children, 20 boys and 20 girls, with a Class II division I malocclusion and protrusive maxilla were treated with orthopedic cervical headgear with a 10 mm expanded inner bow and a long outer bow bent 15 degrees upwards. The mean age of the children at the beginning of treatment was 9.3 years (SD 1.3, range 6.6 to 12.4 years), and the average treatment time was 1.8 years (SD 0.6, range 0.8 to 3.1 years). In all patients Class II molar relationships were successfully corrected to Class I molar relationships. This was accompanied by a marked widening of both maxillary and mandibular dental arches. The cephalometric analysis suggested that the observed improvement of the occlusion was due to an inhibition of forward growth of the maxilla and anterior downward rotation of the palate.

Age Factors↗
PubMed1999

Phospholipids affect stratum corneum lipid bilayer fluidity and drug partitioning into the bilayers.

Phospholipids, e.g. fluid-state EPC (l-alpha-phosphatidylcholine from egg yolk), may diffuse into the stratum corneum and enhance dermal and transdermal drug penetration, while many other phospholipids, e.g. gel-state DSPC (distearoylphosphatidyl choline), are not able to do this. These effects are suggested to be due to the interactions between the phospholipids and the skin lipid bilayers, and so an in vitro method was developed to evaluate the influence of phospholipids on the distribution of drugs to stratum corneum lipids. The distribution coefficients of estradiol, progesterone and propranolol between stratum corneum lipid liposomes (SCLLs) without phospholipids or with EPC, DSPC, SPC (l-alpha-phosphatidylcholine from soybean) or DOPE (dioleylphosphatidyl ethanolamine), and pH 7.4 buffer were determined. Fluid-state phospholipids in SCLLs increased the partitioning of drugs into SCLLs, while gel-state lipid, DSPC, did not. The increased distribution of drugs into the SCLLs was at least partially due to the increased fluidity of SCLL bilayers by phospholipids, which was shown using steady-state fluorescence anisotropy. This in vitro method enables screening of the effects of phospholipids and other permeation enhancers on stratum corneum bilayer fluidity and drug partitioning.

Administration, Topical↗
PubMed1999

Late results of Senning operation.

OBJECTIVES: Few data exist for long-term results after the Senning operation for transposition of the great arteries. Sinus node dysfunction and systemic ventricular dysfunction have been the main problems. We evaluated risk factors for late death and the incidence of late death, sinus node dysfunction, and right ventricular dysfunction in 100 patients. METHODS: The study was a retrospective analysis with a mean follow-up time of 12.8 +/- 3.1 years. No patients were lost to follow-up. Patients were divided in 2 groups according to ventricular septal defect (73 simple, 27 complex). The electrocardiogram, ambulatory electrocardiogram, echocardiogram, and chest radiograph were reviewed for each patient. RESULTS: The overall mortality rate was 10%. The actuarial survival was 90% (simple) and 78% (complex); the probability of staying in sinus rhythm was 34% and 7%, and the probability of normal right ventricular function was 52% and 39%, respectively, 15 years after operation. The incidence of sinus node dysfunction increased gradually over time, although the incidence of right ventricular dysfunction increased rapidly after 10 years of follow-up. Late deaths, arrhythmias, and right ventricular dysfunction were significantly more frequent in the complex group. Right ventricular dysfunction and active arrhythmias were risk factors for late death. CONCLUSION: Long-term follow-up after the Senning operation shows increasing incidence of sinus node dysfunction and right ventricular dysfunction over time. Deteriorating right ventricular function is a major concern. Its early recognition and initiation of appropriate management to preserve cardiac function is an important follow-up goal.

Actuarial Analysis↗
PubMed1999

Liposome-skin interactions and their effects on the skin permeation of drugs.

The aim of the study was to evaluate the interaction of phospholipid liposomes with skin and stratum corneum lipid liposomes (SCLLs). The influence of phospholipid liposomes on the skin permeability of model drugs was also studied. The transdermal flux of the drugs applied in various phospholipid containing formulations through human epidermis was studied in diffusion chambers. Liposomes in water solutions did not enhance the skin permeability of the drugs, but when ethanol (32% w/v) was present in the donor with EPC (egg yolk lecithin), permeabilities of some model drugs were substantially increased. Confocal microscopy studies revealed that EPC do not penetrate into the skin from water solutions, while from ethanol solutions, EPC penetrates deeply into the stratum corneum. Also, resonance energy transfer between different liposome compositions and the release of calcein from SCLLs showed that interactions between phospholipid liposomes and SCLLs increased with increasing ethanol concentration in the liposome solutions.

Adrenergic beta-Antagonists↗
PubMed1997

Changes in dental arch dimensions by use of an orthopedic cervical headgear in Class II correction.

Orthopedic cervical headgears are commonly used in Finland for early treatment of the Class II malocclusion, but there is a lack of follow-up studies on the effect of this treatment. We have evaluated the effects of the cervical headgear therapy with an expanded inner bow to treat Class II malocclusion and dental arches. Forty children, 20 boys and 20 girls, with Class II, Division 1 malocclusion, were treated with the orthopedic cervical headgear. No other appliances were used. The mean age of the subjects in the beginning of the treatment was 9.3 +/- 1.3 years (range 6.6 to 12.4 years). The mean treatment time was 1.8 +/- 0.6 years (range 0.8 to 3.1 years). The cervical headgear was used with a 10 mm expanded inner bow and a 15 degrees upward bend of the long outer bow, 12 to 14 hours a day with a force of 500 gm per side. Class I relationships were achieved in all subjects. At the same time, the maxillary and mandibular dental arches were widened. The annual increment in the intercanine and intermolar distances was significantly greater than in healthy control subjects (literature data), except for the mandibular intercanine distance in boys. The maxillary arch lengths were also significantly increased; there were no consistent changes of the mandibular arch lengths. Class II malocclusion may be treated with the orthopedic cervical headgear. The treatment results in increased growth of the dental arch widths by expansion of the inner bow of the headgear. The widening of the maxilla is followed by spontaneous widening of the mandible.

Child↗
PubMed1996

Interaction of liposomes with human skin in vitro--the influence of lipid composition and structure.

Liposomes have been suggested as a vehicle for dermal and transdermal drug delivery, but the knowledge about the interaction between lipid vesicles and human skin is poor. Therefore, we visualized liposome penetration into the human skin by confocal laser scanning microscopy (CLSM) in vitro. Liposomes were prepared from phospholipids in different compositions and labeled with a fluorescent lipid bilayer marker, N-Rh-PE (L-alpha-phosphatidylethanolamine-N-lissamine rhodamine B sulfonyl). Fluorescently labelled liposomes were not able to penetrate into the granular layers of epidermis. However, the fluorescence from liposome compositions containing DOPE (dioleylphosphatidyl ethanolamine) was able to penetrate deeper into the stratum corneum than that from liposomes without DOPE. Pretreatment of skin with unlabeled liposomes containing DOPE or lyso-phosphatidyl choline (lyso-PC) enhanced the subsequent penetration of the fluorescent markers, N-Rh-PE and sulforhodamine B into the skin, suggesting possible enhancer activity, while most liposomes did not show such enhancement. Resonance energy transfer (RET) and calcein release assay between stratum corneum lipid liposomes (SCLLs) and the phospholipid vesicles suggested that the liposomes containing DOPE may fuse or mix with skin lipids in vitro and loosen the SCLL bilayers, respectively. Among the factors not affecting stratum corneum penetration were: negative charge, cholesterol inclusion and acyl chain length of the phospholipids. In conclusion, fusogenicity of the liposome composition appears to be a prerequisite for the skin penetration.

Drug Carriers↗