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Biomedical subjects

M Laine

Publications and source records attributed to M Laine.

At least 73 records · Page 4Linked to original sources
PubMed1997

Hormone replacement therapy and some salivary antimicrobial factors in post- and perimenopausal women.

OBJECTIVES: The effect of hormone replacement therapy (Cyclabil) on non-immunoglobulin (peroxidase) and immunoglobulin (total IgA, IgG, IgM) antimicrobial factors as well as on total protein and microorganisms in whole saliva was assayed in 19 postmenopausal and 8 perimenopausal women. METHODS: Paraffin-stimulated whole saliva was collected before as well as 3 and 5 months after the onset of the treatment. Time- and group-related differences between post- and perimenopausal women were analyzed. RESULTS: Peroxidase and total protein output per min increased significantly (P = 0.004 and 0.001) during the treatment in both groups. No significant time- or group-related differences in the mean concentrations of the respective variables were found. The mean concentrations of salivary IgA and IgG showed a significant time-related decrease in both groups (P = 0.012 and 0.010). Salivary IgM concentration in perimenopausal women also showed a significant time-related decline (P = 0.017) and the difference in changes of salivary IgM between the two groups was significant (P = 0.033). Total IgA output per min increased in perimenopausal whereas it decreased in postmenopausal women (interaction; P = 0.021). Hormone treatment had no effect on the amount of salivary bacterial floras. CONCLUSIONS: The composition of saliva in post- and perimenopausal women was found to be estrogen-dependent. The second finding was that all women participating in the study reported a sense of enhanced oral well-being including relief of oral dryness.

Adult↗
PubMed1997

Relative alpha desynchronization and synchronization during speech perception.

Brain processes elicited by speech were studied in 10 right-handed subjects by means of examining the desynchronization and synchronization of the 8-10 Hz and 10-12 Hz EEG alpha frequency bands. The subjects listened to an auditorily presented 5 min text passage. The text was presented both forward and backward. Listening to the text forward elicited alpha desynchronization in both of the frequency bands studied, whereas listening to the same text presented backward elicited synchronization in the 10-12 Hz frequency band only. Listening to the text forward elicited greater desynchronization than listening to the text backward. In the 10-12 Hz frequency band, listening to the text forward elicited desynchronization whereas listening to the same text backward elicited synchronization. This dissociation was not observed in the 8-10 Hz frequency band. The results suggest that the lower and upper alpha bands differ such that the 10-12 Hz frequency band exhibits reactivity to the presence of linguistic content while the 8-10 Hz band shows an unspecific response.

Acoustic Stimulation↗
PubMed1997

Febrile infection changes the expression of IgG Fc receptors and complement receptors in human neutrophils in vivo.

We have examined the expression of the IgG Fc receptors (FcRI, FcRII, FcRIII) and complement receptors (CR1, CR3) in neutrophils from 42 patients with febrile bacterial infection, 20 patients with febrile viral infection and 69 non-febrile healthy individuals. Using receptor-specific MoAbs and immunofluorescence flow cytometry the relative fluorescence intensity (as a measure of receptor number) and the proportion of receptor-positive cells were determined in peripheral blood neutrophils exposed to minimal processing, consisting only of erythrolysis. Both the percentage of FcRI-positive neutrophils and FcRI number per neutrophil were significantly (P < 0.001 and P < 0.0001) increased in bacterial infected patients compared with controls, whereas in viral infected patients only the FcRI percentage was markedly elevated (P < 0.05). In addition, both FcRII and CR1 levels were significantly higher in the bacterial infection group than in the viral infection and control groups (bacterial versus control P < 0.001, bacterial versus viral P < 0.0001). No changes in expression of FcRIII or CR3 were found in the patient groups. The kinetic analysis of receptor expression in bacterial infection patients revealed a shift in the percentage of FcRI-bearing neutrophils towards normal values already on day 2 after the first analysis. On the other hand, the levels of FcRI, FcRII and CR1 remained clearly elevated in these patients during 1 week's follow-up period. We conclude that febrile infection may cause systemic activation of the entire pool of circulating neutrophils, resulting in alterations in cell surface receptor expression, some of which are characteristic of the nature of the infectious agent.

Adolescent↗
PubMed1997

Picture naming deficits in vascular dementia and Alzheimer's disease.

Picture naming deficits in Alzheimer's disease (AD) have been extensively studied but less is known about anomia in vascular dementia (VaD). We tested sources of anomia in these two dementia types by administering an extensive naming battery to 10 patients with VaD, 13 patients with probable AD, and 20 healthy age- and education-matched controls. Both dementia groups evidenced a semantic component in their anomia but the semantic deficit was more clearcut in the patients with AD than in the patients with VaD even though the groups were matched on dementia severity. Case-by-case analyses showed considerable performance variability but confirmed that when anomia is present, it commonly has a semantic component in both VaD and AD.

Aged↗
PubMed1996

Lexical retrieval deficit in picture naming: implications for word production models.

In models of word retrieval, it is common to differentiate lexical-semantic (word meaning) and lexical-phonological (word form) levels. There has been considerable interest in the relationship between these two levels. The so-called discrete two-stage model claims that phonological activation follows selection at the lexical-semantic level and is limited only to the selected item. In contrast, nondiscrete (interactive and cascade) models assume that all activated lexical-semantic candidates are also phonologically activated to some extent. We addressed this issue by studying an anomic patient who suffered from a partial functional disconnection between lexical-semantic and lexical-phonological levels. A multitarget repeated naming task with phonological training was employed. Systematic manipulation of semantic and phonological relatedness between the to-be-named items indicated that our patient's word error patterns were sensitive to both types of lexical relatedness. A delayed repetition task employing the same items failed to show similar effects, suggesting that they were specific to naming. The discrete two-stage model is unable to explain the observed effects of semantic and phonological relatedness. However, they are consistent with assumptions of nondiscrete models of lexical retrieval. In addition to the theoretical implications of this study, the observed effects of lexical context on word retrieval have implications for treatment of anomia.

Aged↗
PubMed1996

Androgen receptor in rat Harderian and submandibular glands.

Androgens regulate the development and sexual dimorphism of rodent Harderian and submandibular glands. This effect is believed to be mediated by the androgen receptor. Immunohistochemistry and immunoblotting were carried out to study the receptor in normal, castrated and dihydrotestosterone-supplemented rat Harderian and submandibular glands. Immunohistochemically, the most intense nuclear staining was observed in the acinar cells of the submandibular glands, followed by intercalated duct cells. The granular convoluted tubules showed weak immunostaining and the striated ducts were negative. In the Harderian gland, nuclear staining was seen in both type I and II secretory cells. Castration and treatment had no effect on the expression of the androgen receptor protein in either gland. A 110 K androgen receptor signal was detected by immunoblotting in the Harderian gland but not in the submandibular gland. An experiment was designed to explore the possible effect of proteinases on the receptor protein in the homogenate of submandibular gland. Our results demonstrate the cell-specific location of the receptor in Harderian and submandibular glands, and show that the expression of the receptor protein is androgen-independent.

Animals↗
PubMed1996

Role of calcium in stretch-induced release and mRNA synthesis of natriuretic peptides in isolated rat atrium.

To investigate the role of Ca2+ in stretch-induced synthesis and release of atrial natriuretic peptide (ANP) and B-type natriuretic peptide (BNP) isolated superfused rat atria were stretched by raising intra-atrial pressure. The immunoreactive (ir-) ANP and BNP concentrations were analysed by radioimmunoassay and the corresponding mRNA levels were quantified by Northern blot and dot blot analyses. Stretch-induced ir-ANP release and a rise in BNP mRNA levels increased at high (3.0 mM) compared to low (0.5 mM) extracellular Ca2+ concentration ([Ca2+]o). Moreover, the adaptation of stretch-induced ir-ANP release was dependent on [Ca2+]o. Atrial BNP mRNA levels were increased by stretch also in non-paced, electrically silent atria, where voltage-activated Ca2+ channels are not activated. The stretch-induced rise in BNP mRNA was blocked by gadolinium (80 microM), but not by the L-type channel blocker diltiazem (3.0 microM). This study indicates that both the stretch-secretion coupling of ir-ANP release and the pressure-stimulated synthesis of BNP mRNA are Ca2+-dependent processes. Gadolinium inhibits the stretch-stimulated rise in BNP mRNA levels in contracting and non-contracting atria, which is similar to its ability to block stretch-activated ir-ANP release, suggesting the involvement of Ca2+-permeable stretch-activated channels.

Animals↗
PubMed1996

Effect of hormone replacement therapy on salivary flow rate, buffer effect and pH on perimenopausal and postmenopausal women.

The effects of hormone replacement therapy (HRT) on salivary gland functions were examined in a longitudinal study. The flow rate, buffer effect and pH of paraffin-stimulated whole saliva were analysed in 8 perimenopausal and 19 postmenopausal women. The saliva samples were collected 1-2 days before as well as 3 and 5 months after the start of HRT. Salivary flow rates were higher (p <0.033) in the perimenopausal than in the postmenopausal group. The flow rates increased significantly (p <0.001) during HRT in both groups. Similarly, buffer effect and pH showed significant (p = 0.004 and p = 0.009, respectively) time-related changes without any differences between the groups. It appears that HRT improves both the quantity and the quality of salivary gland function in peri- and postmenopausal women.

Adult↗
PubMed1996

Event-related EEG desynchronization and synchronization during an auditory memory task.

Event-related desynchronization (ERD) and synchronization (ERS) of the lower (8-10 Hz) and upper (10-12 Hz) alpha bands of background EEG were studied in 10 subjects during an auditory memory scanning paradigm. Each experimental trial started with the presentation of a visual warning signal, after which an auditory 4-vowel memory set was presented for memorization. Thereafter the probe, a fifth vowel, was presented and identified by the subject as belonging or not belonging to the memorized set. In 50% of the cases, the probe was among the previously presented memory set. The presentation of the memory set elicited a significant ERS in the both alpha frequency bands. In contrast, the presentation of the probe elicited a significant bilateral ERD in both alpha frequency bands studied. The results suggest that the ERD phenomenon is closely associated with higher cortical processes such as memory functions rather than with auditory stimulus processing per se. Event-related desynchronization provides a potentially valuable tool for studying cortical activity during cognitive processing in the auditory stimulus modality.

Adult↗
PubMed1996

Semantic processing without conscious understanding in a global aphasic: evidence from auditory event-related brain potentials.

We report a global aphasic who showed evidence of implicit semantic processing of spoken words. Auditory event-related brain potentials (ERPs) to semantically congruous and incongruous final words in spoken sentences were recorded. 17 elderly adults served as control subjects. Their ERPs were more negative to incongruous than to congruous final words between 300 and 800 ms after stimulus onset (N400), and more positive between 800 and 1500 ms (Late Positivity). The aphasic showed an exactly similar pattern of ERP components as the controls did, but his performance in a task demanding explicit differentiation between semantically congruous and incongruous sentences was at the chance level. During follow-up, his explicit understanding recovered over the chance level but the ERPs remained fairly similar. We conclude that implicit semantic activation at the conceptual level can take place even in the absence of conscious (explicit) comprehension of the meaningfulness of linguistic stimuli.

Acoustic Stimulation↗
PubMed1996

A video-based method for evaluation of low-back load in long-cycle jobs.

A method for evaluation of the physical load on the lumbar spine in industrial work is presented. It is suitable for identification of high spinal loads and their time duration. The method is based on biomechanical analysis of video-recordings. It takes into account the posture of the body as such, as well as the possible occurrence of external load and support. Compression of the L5-S1 intervertebral disc and strain on the lumbodorsal fascia is determined at 5-s intervals in each work task.

Biomechanical Phenomena↗
PubMed1996

Effect of gadolinium on stretch-induced changes in contraction and intracellularly recorded action- and afterpotentials of rat isolated atrium.

1. Atrial arrhythmias, like atrial fibrillation and extrasystoles, are common in clinical situations when atrial pressure is increased. Although cardiac mechanoelectrical feedback has been under intensive study for many years, the mechanisms of stretch-induced arrhythmias are not known in detail. This is partly due to methodological difficulties in recording intracellular voltage during stretch stimulation. In this study we investigated the effects of gadolinium (Gd3+), a blocker of stretch-activated (SA) channels, on stretch-induced changes in rat atrial action potentials and contraction force. 2. By intracellular voltage recordings from rat isolated atria we studied the effects of Gd3+ (80 microM) on stretch-induced changes in action potentials. The stretch was induced by increasing pressure inside the atrium (1 mmHg to 7 mmHg). An elastic electrode holder that moved along the atrial tissue was used in the recordings. Thus the mechanical artifacts were eliminated and the cell-electrode contact was made more stable. To examine the influence of Gd3+ on atrial contraction we stretched the atria at different diastolic pressure levels (1 to 7 mmHg) with Gd3+ application of (80 microM) or diltiazem (5.0 microM). Contraction force was monitored by recording the pressure changes generated by the atrial contractions. 3. Our results show that: (1) atrial stretch induces delayed afterdepolarizations (DADs), increase in action potential amplitude and increase in relative conduction speed; (ii) Gd3+ blocks stretch-induced DADs and action potential changes; (iii) Gd3+ inhibits pressure-stimulated increase in the atrial contraction force, while similar inhibition is not observed with diltiazem, a blocker of L-type calcium channels. 4. This study suggests that Gd3+ inhibits stretch-induced changes in cell electrophysiology and contraction in the rat atrial cells and that the effects of gadolinium are due to rather specific block of stretch-activated ion channels with only a small effect on voltage-activated calcium channels.

Action Potentials↗
PubMed1995

Low back pain in the young. A prospective three-year follow-up study of subjects with and without low back pain.

STUDY DESIGN: This was a prospective 3-year follow-up study of randomized matched subgroups of 15-year-old school children with or without low back pain initially. OBJECTIVE: In addition to low back pain and leisure time physical activity, spinal mobility, trunk muscle strength, and early degenerative findings of the lumbar spine were evaluated. SUMMARY OF BACKGROUND DATA: Reliable epidemiologic studies on the prevalence of low back pain and development of early degenerative changes of the lumbar spine in young persons have been sparse. Along with several other characteristics, the relationship of these changes to frequent low back pain in young persons is not known. METHODS: After a questionnaire-based survey was administered, subjects with or without low back pain were examined initially and at follow-up with special reference to leisure time physical activity, anthropometry, spinal mobility, trunk muscle strength, and magnetic resonance imaging findings of the lumbar spine. RESULTS: At baseline and at follow-up, those subjects with initial low back pain were characterized by a low frequency of physical activity and decreased spinal function. During follow-up, the occurrence of disc degeneration increased significantly more in the original group with low back pain than among asymptomatic subjects. Furthermore, disc degeneration at baseline significantly predicted future frequent low back pain. Initial disc protrusion also predicted future frequent low back pain. CONCLUSION: After the rapid physical growth period, there seemed to be a causal relationship between the early evolution of the degenerative processes of the lower lumbar discs and frequent low back pain in several subjects.

Adolescent↗