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Biomedical subjects

A Lundström

Publications and source records attributed to A Lundström.

At least 37 records · Page 2Linked to original sources
PubMed1991

Proportional analysis of the facial profile in natural head position in Caucasian and Chinese children.

A proportional analysis of the facial soft tissue profile in natural head position involving 11 indices (ratios), was applied to 80 Caucasian, and 80 Chinese male and female 12-year-old children in Hong Kong. The analysis is based on the true horizontal and the porion vertical, and has the advantage that its foundation lies on a more stable (less growth affected) region of the head compared to profile soft tissue landmarks. Measurements were made on cephalograms recorded in natural head position. Male subjects were larger than the females for most of the horizontal measurements, but for both population samples the vertical measurements displayed virtually no significant intersex differences at 12 years. No very significant intersex differences were found for the proportional indices. Ethnic differences were mainly found with the horizontal measurements. Relative to the porion vertical the Caucasian children were more protrusive over soft tissue nasion, nose tip, and sulcus labialis superior, whilst the Chinese displayed more protrusion over the lower lip and sulcus labialis inferior. Ethnic proportional differences relative to nasion were combined with a shorter porion-nasion distance in the Chinese as compared with the Caucasian children. The sella-nasion line was found to be more forwards-upwards inclined in Chinese than Caucasian children. It was concluded that a proportional soft tissue profile analysis, based on natural head position, is a useful method for the comparison of ethnic population groups. This study amplified ethnic differences previously reported by Cooke (1986) and Cooke and Wei (1989).

Asian People↗
PubMed1991

Intercellular lamellar lipids in plantar stratum corneum.

Plantar stratum corneum was examined by means of transmission electron microscopy after conventional osmium fixation and after fixation with ruthenium tetroxide. The latter fixative was used in order to reveal the possible existence of lamelarly ordered lipids in the intercellular space, as has previously been demonstrated for non-palmo-plantar stratum corneum. A major part of the plantar stratum corneum intercellular space was occupied by extracellular parts of desmosomes. In specimens fixed with ruthenium tetroxide the intercellular space not occupied by desmosomes was found to contain multiple alternating electron dense and electron lucid bands, suggestive of membraneous structures. This pattern appeared to be similar to that previously described for non-palmo-plantar stratum corneum. It is suggested that the intercellular lipids of palmo-plantar stratum corneum may be qualitatively similar to the intercellular lipids of non-palmo-plantar stratum corneum. The lower lipid content, expressed as weight per unit weight of tissue, in palmo-plantar stratum corneum as compared to non-palmo-plantar stratum corneum may be related to the fact that a larger portion of the intercellular space of the former tissue is occupied by desmosomes. The relatively high water permeability of palmo-plantar stratum corneum implies that desmosomes, i.e. non-lipid regions of the intercellular space, may have a high water permeability and hence could establish a hydrophilic route through the stratum corneum.

Body Water↗
PubMed1991

Stratum corneum chymotryptic enzyme: a proteinase which may be generally present in the stratum corneum and with a possible involvement in desquamation.

A chymotrypsin-like proteinase that may be involved in the desquamation process in plantar stratum corneum has recently been partially characterized. The aim of the present study was to elucidate whether a similar proteinase is also present in non-palmo-plantar stratum corneum. Stratum corneum was obtained by tape stripping of volar forearm skin after the skin surface had been painted with colourless nail varnish. The adherent tissue was released from the tape strips by acetone treatment, then extracted with diethyl ether and dried. Extracts of this acetone-ether powder were analyzed with respect to proteolytic activity by means of electrophoresis under non-reducing conditions in polyacrylamide gels containing sodium dodecyl sulphate and casein. The extracts were found to contain one major chymotrypsin-like proteinase with an apparent molecular weight of around 25 kDa, and several minor proteinases with trypsin-like activity. The 25 kDa proteinase was active at pH 5.5-8, and could be inhibited by aprotinin, chymostatin and zinc ion, but not by leupeptin. No difference could be found between the 25 kDa enzyme in forearm stratum corneum and the recently described chymotrypsin-like enzyme in dissociated plantar stratum corneum cells as regards electrophoretic mobility, pH dependency, and inhibitor profile. The fact that the enzyme could degrade casein at pH 5.5 and that it appears to be present in stratum corneum in general suggests that it may play a role in the desquamation process under in vivo conditions. The tentative name "stratum corneum chymotryptic enzyme" is proposed for this newly discovered proteinase.

Cell Adhesion↗
PubMed1990

Cell shedding from human plantar skin in vitro: evidence that two different types of protein structures are degraded by a chymotrypsin-like enzyme.

A recently described endogenous proteolytic process in pieces of human plantar stratum corneum incubated in vitro has been further studied. This process leads to a decrease in cohesion between the cells that had been facing outwards in vivo. Using two methods, that differed with respect to efficiency, to detach surface cells with decreased cohesion, the process could be divided into two steps. The first step took place irrespective of the presence of ethylenediaminetetraacetate (EDTA) and led to a moderate decrease in cohesion between surface cells. The second step occurred only in the presence of EDTA and advanced to a point where the surface cells could be separated from the remaining cohesive tissue pieces by simple agitation. Both degradation steps could be inhibited by aprotinin and chymostatin but not by leupeptin. Zinc sulfate inhibited the first step. The results indicate that there are two different types of protein structures being degraded during the process of cell shedding in vitro. A chymotrypsin-like enzyme may be involved in the process.

Aprotinin↗
PubMed1990

Gingival blood flow and temperature changes in young humans with a history of periodontitis.

Whether such individuals have different gingival blood flow and temperature responses to local cooling than age- and sex-matched healthy controls was tested. Ten patients with a history of localized juvenile periodontitis or rapidly progressive periodontitis were selected from a periodontal clinic and matched with healthy controls. Gingival blood flow and temperature were monitored continuously before and after cooling via a twin probe placed in the gingival sulcus on the buccal of tooth No. 26. Blood flow was assessed by laser Doppler flowmetry and temperature by a small metal thermistor. Resting values were first recorded for 5 min, followed by 3 min of cooling to 19 degrees C by a gentle stream of cool air, then 12 min of rewarming was allowed. This protocol was repeated twice. Blood flow changes were analysed as the slope of the line formed between the last 2 min of cooling and the last 2 min of rewarming; temperature curves were analysed by a least-squares curve fit of a bi-exponential function. Patients with localized juvenile periodontitis and rapidly progressive periodontitis had similar rewarming temperature curves, but significantly faster blood flow recovery curves than controls (p less than 0.03). Thus, gingival blood flow in young periodontitis patients recovered more rapidly after local cooling than in healthy controls.

Adolescent↗
PubMed1990

The dependence of detergent-induced cell dissociation in non-palmo-plantar stratum corneum on endogenous proteolysis.

We have recently shown that cell cohesion in plantar stratum corneum is mediated to a significant extent by protein structures, and that endogenous proteolysis plays an important role in desquamation in this tissue. This paper is a report of our investigations into whether similar mechanisms for cell cohesion and desquamation can be found in non-palmo-plantar stratum corneum. Biopsies of non-palmo-plantar human skin were incubated at 37 degrees C, pH 8, in a buffer with and without additions of detergents (a mixture of N,N-dimethyldodecylamine oxide and sodium dodecyl sulphate), ethylene diamine tetraacetate (EDTA), and the proteinase inhibitor aprotinin. Released cells were examined by phase contrast microscopy and counted. The incubated biopsies were examined by light microscopy. As has been previously shown by others, we found that in the presence of detergents there was a dissociation of stratum corneum cells. This dissociation was stimulated by EDTA and inhibited by aprotinin. After 36 h of incubation the entire stratum corneum and, on some parts of the biopsies, the stratum granulosum had dissociated. There was no evidence of cell dissociation in the spinous or basal epidermal layers. We conclude that the detergent-induced cell dissociation in non-palmo-plantar human stratum corneum is dependent on the action of proteinases present in the tissue on protein structures. These structures may be of significant importance for non-palmo-plantar stratum corneum cell cohesion.

Aprotinin↗
PubMed1990

Evidence that cell shedding from plantar stratum corneum in vitro involves endogenous proteolysis of the desmosomal protein desmoglein I.

We have recently described a process leading to a unipolar cell shedding from pieces of plantar stratum corneum incubated in vitro, which seems to be dependent on the activity of a serine proteinase. This process has been studied further. Electron microscopy studies suggest that cell dissociation is preceded by a degradation of the intercellular parts of desmosomes. An antiserum was raised against the transmembrane protein desmoglein I (DG I) of bovine desmosomes. In extracts of layers of plantar stratum corneum with strong intercellular cohesion, this antiserum reacted with a protein of the same apparent molecular weight as bovine DG I. In dissociated cells this DG I-like protein could not be detected; instead components with molecular weights lower than DG I which reacted with the antiserum were found. During incubation of pieces of plantar stratum corneum, under conditions leading to unipolar cell shedding, there was a progressive decrease in the amounts of the DG I-like protein, and the appearance of the lower molecular weight components with DG I-like immunoreactivity. This apparent degradation of the DG I-like protein was inhibited by aprotinin, chymostatin, and zinc ion, but not by leupeptin. The results suggest that proteolytic degradation of desmosomes may be an important part of the process leading to cell dissociation in plantar stratum corneum in vitro, and that desmosomes may play an important role in plantar stratum corneum cell cohesion.

Animals↗
PubMed1989

Panel assessments of the facial frontal view as related to mandibular growth direction.

This paper describes study No. 6 in a series dealing with mandibular growth direction (Lundström and Woodside, 1980). Study No. 5. (Lundström, Woodside and Popovich 1987) investigated facial harmony and disharmony of the facial profile. The present paper describes a study of the frontal views of the same children as paper No. 5. A mixed panel of 17 individuals (four categories of three, four and six people in each) made an aesthetic evaluation of the frontal facial view of 64 subjects (32 of each sex) from the Burlington serial experimental group. The sample consisted of equal numbers of individuals who displayed vertical, average or horizontal mandibular growth between the ages 6-20 years. We calculated correlations between the four assessor groups and found these to be acceptable. On average the panel found no change in frontal appearance between 12 and 18 years because of the balance between individuals improving and deteriorating. Our earlier work showed systematic differences in profile view between those with vertical growth on the one hand and average o horizontal on the other. The vertical cases were more disharmonious than the other categories. Corresponding findings were made also in the frontal view. Mean overall evaluations by all assessors showed a positive correlation between profile and front view assessments.

Adolescent↗
PubMed1989

Clinical evaluation of maxillary and mandibular prognathism.

This study focuses on the importance of using natural head posture as a basis for cephalometric analysis. It describes a simple method for transferring a vertical plumbline from a lateral head photograph to a profile radiograph. The method is shown to have a relatively small technical error. Means and standard deviations for the angles HOR/N-A and HOR/N-B between the horizontal line (HOR) on one side and the nasion-subspinale (A-point) and nasion-supramentale (B-point) lines on the other, in random individuals, are presented as standards from which individual cases can be evaluated.

Adolescent↗
PubMed1989

Stepwise modifications of keratin polypeptides during keratinization in palmar-plantar epidermis.

Precursor-product relationships among keratin polypeptides (cytokeratins) were studied in living and cornified layers of palmar-plantar epidermis. Serial 10 microns horizontal freeze-cut sections of punch biopsies were analysed by means of light microscopy and one-dimensional electrophoresis in a system that permitted identification of all major keratin polypeptides with apparent molecular weights over 60 kDa. Peptides that appeared to be related were compared by means of peptide mapping after partial proteolysis. The results suggest that both the basic-neutral (type II) cytokeratin no. 1 and the acidic (type I) cytokeratin no. 9 undergo two distinct modification steps with subsequent decreases in apparent molecular weight during keratinization. For both polypeptides the first modification appeared to take place and run to completion in close relation to the transition between the uppermost living epidermal layers and the lowest cornified layers. The second conversions of cytokeratins nos. 1 and 9 both appeared to take place within the stratum corneum but differed in two respects: 1) they appeared to start at different tissue sites; 2) whereas the second modification step appeared to comprise all cytokeratin 1 molecules, only a fraction of the cytokeratin 9 molecules passed through this step. These variations suggest that the different modification steps may be produced by different mechanisms that are regulated separately. It is concluded that the processing of cytokeratins during keratinization may be more complex than has previously been realized.

Electrophoresis, Gel, Two-Dimensional↗
PubMed1989

Immunochemical analysis of the distribution of the desmosomal protein desmoglein I in different layers of plantar epidermis.

An antiserum raised against the bovine desmosomal protein desmoglein I (DGI), Mr approximately 160 kDa, was used in an immunochemical analysis of human plantar epidermis. Different layers of the tissue were prepared by means of horizontal freeze sectioning. Loosely attached surface layers were obtained by means of scraping of the skin surface with a scalpel. Tissue extracts were analysed by means of sodium dodecylsulphate polyacrylamide gel electrophoresis followed by immunoblotting. Significant amounts of a component with Mr approximately 160 kDa, reactive with the DG I-antiserum, were found in all layers except the loosely attached surface layers. In these layers the antiserum detected a component with Mr approximately 80 kDa, not found in other layers. This component may be a degradation product of DG I. Since DG I belongs to the group of transmembrane desmosomal proteins that is believed to constitute the link between the intracellular parts of desmosomes of opposing cells, it is concluded that desmosomes may play an important role in plantar stratum corneum cell cohesion, and that degradation of desmosomes may be an important step in desquamation in plantar epidermis.

Adult↗
PubMed1988

Cell shedding from human plantar skin in vitro: evidence of its dependence on endogenous proteolysis.

Cell shedding from plantar stratum corneum was studied in vitro. Cells were shed only from the surface that had faced outwards in vivo. A quantitative measure of the cell release was obtained by determining the amount of protein that could be extracted from released and sedimented cells with 1 M sodium hydroxide. The cell release was optimal at pH 7-9 but was significant also at pH 6. The rate of cell release increased with increasing temperature, but was decreased abruptly at temperatures above 50 degrees C. The cell dissociation could be inhibited by aprotinin (Trasylol) and soybean trypsin inhibitor. Thus, it is evident that the unipolar cell dissociation in this system is mediated by an enzymatically catalyzed process, most likely with the involvement of a serine protease with an alkaline pH-optimum. The in vitro cell release shows properties indicating that it may be mediated by mechanisms also active in vivo.

Cell Adhesion↗