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Biomedical subjects

V B Meyer-Rochow

Publications and source records attributed to V B Meyer-Rochow.

At least 19 recordsLinked to original sources
PubMed2006

Depressive symptoms and insulin resistance in young adult males: results from the Northern Finland 1966 birth cohort.

The association between insulin resistance (IR) and depression is a subject of growing research interest, especially as previous population-based studies have presented conflicting findings. The present study extends our understanding about the putative impact of the severity of depressive symptoms on this association and it provides further epidemiological evidence in support of earlier findings, suggesting that the association between IR and depression is present already in young adult males. To determine the impact of the severity of depressive symptoms on the putative association between IR and depression in young adult males, we were given access to the Northern Finland 1966 Birth Cohort database. During the 31-year follow-up survey of this genetically homogeneous birth cohort, IR was assessed by 'Qualitative Insulin Sensitivity Check Index' (QUICKI), and severity of depressive symptoms by 'Hopkins' Symptom Checklist-25' (HSCL-25). This study involved 2,609 male cohort members with complete variable information. In men, the means of the QUICKI-values decreased (i.e., IR increased) in line with the increased severity of depressive symptoms as assessed by HSCL-25 subgroups (analysis of covariance P-value for trend, P=0.003). In multivariate generalized logistic regression analyses, after adjusting for confounders, IR was positively associated with current severe depressive symptoms, the odds ratio (OR) being over threefold (adjusted OR 3.15, 95% confidence interval 1.48-6.68) and the value of OR increased in parallel with a tighter definition of IR (P-value for trend=0.007). The results indicate that in young males, a positive association exists specifically with severe depressive symptoms.

Cohort Studies↗
PubMed2005

Photoreceptor cell types in the retina of the tuatara (Sphenodon punctatus) have cone characteristics.

The tuatara Sphenodon punctatus, restricted to a few New Zealand offshore islands and now strictly protected, belongs to the Rhynchocephalia, the smallest order of extant reptiles. Earlier light microscopical studies on the retina of this species described photoreceptors with both rod- and cone-like features and the presence of a fovea. A limited amount of retinal material from S. punctatus has now allowed us to prepare the first-ever electron microscopic observations on the eye of this reptile. We were able to distinguish three types of photoreceptor, all with fine structural features characteristic of cone cells. Large single cones as well as double cones had open discs in their outer segments and straight axons with pedicle-type terminals. An additional cone type, characterized by somewhat more slender inner and outer segments, vitreally-displaced cell bodies and oblique axons, resembled short-wavelength cones known from other sauropsids. No cells with rod characteristics could be confirmed in the samples, although they might occur in retinal regions not available for this study. We conclude that the tuatara has cone-like photoreceptors, which-as in other crepuscular or nocturnal reptiles-have acquired rod-like features. The phenotypic adaptations notwithstanding, the set of photoreceptor types is quite typical of the reptilian eye and in some respects reminiscent of those seen in lizards and turtles.

Animals↗
PubMed2003

First immunocytochemical study of echinoderm smooth muscle: the Antarctic cushionstar Odontaster validus Koehler (Echinodermata, Asteroidea).

Our immunocytochemical observations reveal that the muscle present in the tips of the arms of the Antarctic cushionstar Odontaster validus contains caldesmon and calponin but not troponin. Thus, the muscle clearly belongs to the smooth muscle category. Distributions of contractile proteins such as actin, myosin (the latter a typical vertebrate muscle filament protein), paramyosin, and miniparamyosin (the latter two being characteristic of thick invertebrate muscle filaments) were also determined immunocytochemically. The results suggest that the thin filaments of the starfish smooth muscle are similar to those of the vertebrate muscle, but that the thick filaments differ from those of vertebrates and possess traits that are also seen in the muscle organization of invertebrates. The absence from the O. validus muscle of titin and nebulin, proteins so far known almost exclusively from the striated vertebrate muscle, comes as no surprise, but immunoreactivity to mini-titin (a protein of the same family as titin and its replacement in invertebrates) was strong and unambiguously recognizable between filaments. Odontaster validus' histochemical characteristics may be a reflection of the phylogenetic position of the echinoderms as deuterostome invertebrates or they may express an adaptation of the muscle to the harsh environmental conditions under which it has to function in the Antarctic water.

Actins↗
PubMed2003

Atopy and depression: results from the Northern Finland 1966 Birth Cohort Study.

Several studies have suggested an association between IgE-mediated atopic allergies and depression. The present study extends our understanding about putative gender differences of this association and provides further epidemiological evidence for our previous finding that the association between atopy and depression may be characteristic for females only. In order to clearly determine the presence of atopic disorders and depression, we used more valid tools than had been employed earlier and we had access to a database (the Northern Finland 1966 Birth Cohort), in which individuals were followed up prospectively until the age of 31 years. The information on allergic symptoms, verified by skin-prick tests and comprising data of 5518 individuals, was used to ascertain the presence of atopy. Depression was assessed with the help of Hopkins' Symptom Checklist-25 and self-reported doctor-diagnosed depression. After adjusting for a father's social class, mother's parity, and place of residence, logistic regression analyses showed that the risk of developing depression increased in parallel with the increasing severity of depression and, when compared with nonatopic subjects, was 3.0 to 4.7-fold up in atopic females and statistically significant. In atopic males, the association between atopy and depression was statistically significant only in the highest depression scores, the odds ratio being 6.3-fold. The results indicate that females suffering from atopic diseases might possess an elevated risk of developing depression already during early adulthood. In males, the association between these two disorders is evident only among the most severe manifestations of depression. Possible background theories, that is, genetic abnormalities in serotonin metabolism, HPA-axis dysfunction, and histamine theory are discussed.

Adult↗
PubMed2003

Suicides in persons suffering from rheumatoid arthritis.

OBJECTIVE: To assess the demographic and psychosocial profiles of patients with rheumatoid arthritis (RA) who committed suicide. Two control groups were used: osteoarthritis (OA) and suicide victims with neither RA nor OA. METHOD: A study based on a prospective, 13-yr follow-up database with linkage to national hospital discharge registers of all suicides (1296 males, 289 females) committed during the years 1988-2000 in the province of Oulu situated in northern Finland. RESULTS: Females were significantly over-represented among RA patients who committed suicide (52.6% RA women vs 17.3% women with neither RA nor OA). Comorbid depressive disorders preceded suicides in 90% of the female RA patients. Before their suicide, 50% of the female RA patients (vs 11% of the male RA patients) had experienced at least one suicide attempt. The method of suicide was violent in 90% of the RA females. RA males were less often depressive, but committed suicide after experiencing shorter periods of RA and fewer admissions than females. CONCLUSION: Attempted suicides and especially depression in female RA patients should be taken more seriously into account than previously in clinical work so that the most appropriate psychiatric treatment can be provided for such patients.

Adult↗
PubMed2002

Selective photoreceptor damage in four species of insects induced by experimental exposures to UV-irradiation.

Damage to photoreceptive cells of insect compound eyes exposed to abnormally high doses of UV-radiation of 350nm peak wavelength manifests itself in at least two different ways. In the butterflies Papilio xuthus and Pieris napi from Japan and northern Finland, respectively, only the cell bodies of retinula cells 1 and 2, (identified as short wavelength receptors), but not their corresponding rhabdomeres, exhibit damage with apoptotic features. In the eye of UV-irradiated adult crickets, however, cell bodies and cytoplasm remain normal, while the rhabdomeres of cells 7 and 8 exhibit signs of severe membrane disruptions. No signs of damage whatsoever occurred in the eyes of northern Finnish bumblebees exposed to UV. It is suggested that metabolic shortfalls in the UV-sensitive cells of the butterfly eyes result in cellular shut-down, but that in the cricket receptors UV-induced changes of the membrane lipids dominate, leading to membrane instability without concomittant cell death. The strong resistance of the bumblebee eye to UV-induced damage requires further investigation, but since preconditioning to light can reduce photic damage in the rat eye, the 24h daylight experienced by northern Finnish bumblebees during the summer season could be involved.

Animals↗
PubMed2001

Smooth muscle proteins as intracellular components of the chromatophores of the Antarctic fishes Pagothenia borchgrevinki and Trematomus bernacchii (Nototheniidae).

Melanophores, xanthophores, and iridophores from the skins of the two Antarctic fish species Pagothenia borchgrevinki and Trematomus bernacchii were tested immunocytochemically for the presence of a variety of muscle proteins. Actin, myosin, and calmodulin, not surprisingly, were confirmed for all three chromatophore types of the two fishes, but the presence of caldesmon and calponin, both characteristic proteins of smooth muscle fibers, represents a new discovery. It is not known at this stage whether these proteins occur also in the chromatophores of other fishes and are not restricted to Antarctic species. Since, however, motility control of particles in fish chromatophores and the regulation of smooth muscle tension both involve the sympathetic nervous system, the presence of similar target proteins should not come as a surprise. The fact that none of the chromatophores tested positive for troponin shows that there is no close relationship between pigment cells and striated muscle. The lack of alpha-actinin in iridophores, but its presence in melanophores and xanthrophores, is thought to be a reflection of the considerably greater pigment translocations within the latter two types of chromatophore cells.

Animals↗
PubMed2001

Diurnal changes in retinula cell sensitivities and receptive fields (two-dimensional angular sensitivity functions) in the apposition eyes of Ligia exotica (Crustacea, Isopoda).

The structural organization of the retinula cells in the eye of Ligia exotica changes diurnally. At night, the microvilli elongate, losing the regular and parallel alignment characteristic of the day condition. Crystalline cones and distal rhabdom tips are not pushed into each other during the day, but at night the rhabdoms protrude into the crystalline cones by up to 5 microm. Screening pigment granules in the retinula cells disperse during the night, but migrate radially towards the vicinity of the rhabdom during the day. No such displacements of the pigment granules of either distal or proximal screening pigment cells were observed. The sensitivity of the eye, monitored by electroretinogram (ERG) recordings, changes diurnally: values at midnight are, on average, 10 times those occurring during the day. However, intracellular recordings from single retinula cells (50 during the day and 50 at night) indicate that the difference between night and day sensitivities is only 2.5-fold. Two-dimensional angular sensitivity curves, indicative of a single unit's spatial sensitivity, had considerably less regular outlines at night than during the day. If based on the 50 % sensitivity level, day and night eyes possessed receptive fields of almost identical width (approximately 2 degrees), but if sensitivities below the 50 % limit were included, then receptive fields at night were significantly more extensive. We suggest that the morphological adaptations and diurnal changes in chromophore content seen in the apposition eye of L. exotica allow this animal to improve its photon capture at night while preserving at least some of the spatial resolving power characteristic of the light-adapted state. This would explain why this animal is capable of performing complex escape behaviours in the presence of predators both in bright and in very dim light.

Animals↗
PubMed2001

The crustacean eye: dark/light adaptation, polarization sensitivity, flicker fusion frequency, and photoreceptor damage.

Compound eyes, nauplius eyes, frontal organs, intracerebral ocelli, and caudal photoreceptors are the main light and darkness detectors in crustaceans, but they need not be present all at once in an individual and in some crustaceans no photoreceptors whatsoever are known. Compound eye designs reflect on their functions and have evolved to allow the eye to operate optimally under a variety of environmental conditions. Dark-light-adaptational changes manifest themselves in pigment granule translocations, cell movements, and optical adjustments which fine-tune an eye's performance to rapid and unpredictable fluctuations in ambient light intensities as well as to the slower and predictable light level changes associated with day and night oscillations. Recycling of photoreceptive membrane and light-induced membrane collapse are superficially similar events that involve the transduction cascade, intracellular calcium, and membrane fatty acid composition, but which differ in aetiology and longterm consequence. Responses to intermittant illumination and linearly polarized light evoke in the eye of many crustaceans characteristic responses that appear to be attuned to each species' special needs. How the visual responses are processed more centrally and to what extent a crustacean makes behavioural use of e-vector discrimination and flickering lights are questions, however, that still have not been satisfactorily answered for the vast majority of all crustacean species. The degree of light-induced photoreceptor damage depends on a large number of variables, but once manifest, it tends to be progressive and irreversible. Concomittant temperature stress aggravates the situation and there is evidence that free radicals and lipid hydroperoxides are involved.

Adaptation, Ocular↗
PubMed2001

Effects of light and darkness on cell deaths in damaged retinal ganglion cells of the carp retina.

Effects of light and darkness on the apoptosis of retinal ganglion cells (RGCs) in young carp were measured by TUNEL method after transection of the optic nerve. Following the operation, the fish were kept under one of four regimens; constant darkness (DD), constant light (LL), 12 hr light and 12 hr dark (LD) and 3 hr of flickering light followed by 21 hr in the dark (FL). On day 3, the highest ratio of apoptotic RGCs was seen under conditions of DD, followed by LL, LD, and FL. On day 6, the percentages of apoptotic RGCs were lower under every experimental condition than what they had been earlier on day 3, but the same ranking order was maintained. Immunohistochemically it could be shown that phosphorylated ERKs were more intensively localized in FL rather than DD retinas. The results suggest that illumination regimens, and in particular cyclic diurnal light/dark changes, have an influence on the degree of apoptosis of damaged RGCs, and that inhibition of apoptosis is correlated with the higher expression of phosphorylated ERKs.

Adaptation, Ocular↗
PubMed2001

Light of my life--messages in the dark.

Luminescent lures, counter-shading in the dark blue sea, flashes of light intensive enough to temporarily blind a predator, love fireworks in the night to impress a mate, and toadstools that glow to attract parasitic wasps--these are just some of the many examples of bioluminescence at work in Nature. But how is the biological light produced? What are its evolutionary roots? Why are there so many different uses for the light?

Animals↗
PubMed2000

Light activation of phospholipase A2 in the photoreceptor of the crayfish (Procambarus clarkii).

Retinal lipids of crayfish, kept at 4 degrees C under continuous darkness for 3 weeks, consisted mainly of phosphatidylcholine (PC) and phosphatidylethanolamine (PE); sphingomyelin (SM), phosphatidylinositol (PI) and phosphatidylserine (PS) were minor contributors. PI, involved in the phototransduction cascade, never reached greater concentrations than 7% of the total. High concentrations of polyunsaturated fatty acids (PUFA) such as 20:4n-6, 20:5n-3 and 22:6n-3 (DHA, docosahexaenoic acid) were present in PC, PE and PS, but scarce in SM and PI. In retinae of crayfish kept at 4 degrees C in darkness for 3 weeks and then exposed to white light (6 h; ca. 4,500 lx), SM and PS remained seemingly unaffected. PC, however, significantly decreased within 10 min to 65% of the initial value and 50% at 180 min. To study the reduction of PC, lipids of retinae suspended in physiological solution with/without phospholipase C (PLC) and phospholipase A2 (PLA2) inhibitors such as DMDA (= DEDA), manoalide, ET-18-OCH3, and U-73122 were measured. Only free fatty acids (FFA) of retinae with inhibitors of PLA2 like DMDA and manoalide decreased. Retinae irradiated by white light for 3 h displayed a significant reduction of PC, compared with those that had remained in continuous darkness. However, the PC of retinae with PLA2-inhibitors was not decreased by light. Our results provide evidence that not only photoreceptor cell PLC, but also PLA2 is activated by light.

Animals↗
PubMed2000

Risks, especially for the eye, emanating from the rise of solar UV-radiation in the Arctic and Antarctic regions.

Physical and biological characteristics of solar UV-radiation wavebands A, B, and C are explained and information is provided on UV-levels in particular environments and ocular tissues. The question whether or not the rise in circumpolar UV of the last 20 years or so can be regarded as a threat is briefly addressed and it is concluded that even if no threat to photosynthetic productivity of crops and vegetation exists, there is a danger regarding the status of health of human skin and eyes (in particular the lens). The nature of the UV-induced damage to cornea, lens, and even the retina with its photo-receptive cells and pigment epithelium is assessed and a word of caution is sounded with regard to possible injury-potentiating effects of certain chemicals as seen, for instance, in the recent and alarming rise of cataract in Scottish salmon. Finally, because of the multifaceted effects of UV (e.g. at molecular, cellular, tissue, individual, population, and ecosystem level), a plea is made for a concerted, well-funded, international effort to tackle the many remaining problems at all fronts and from all possible angles.

Antarctic Regions↗
PubMed1999

Immunocytochemical observations on pineal organ and retina of the Antarctic teleosts Pagothenia borchgrevinki and Trematomus bernacchii.

In spite of the unique conditions they have to operate under, the pineal organs of Antarctic fishes have not previously been examined. We determined immunohistochemically that in the end-vesicles and the pineal stalks of Pagothenia borchgrevinki (a species found directly beneath the sea-ice) as well as Trematomus bernacchii (a species preferring somewhat deeper water than the former) at least two populations of physiologically-different cells occurred that displayed reactions indicative of typical vertebrate photoreceptors. Comparisons with immunocytochemically treated retinal sections from the eyes of the same two species showed that anti-opsin reactivity, characteristic of rods, was particularly strong in the lumina of the pineal stalks of both species. Anti-visinin reactions stained cones in the retinal sections of both fishes and occurred throughout the pineal organs, but in particular in the end vesicles of the pineals of both species. The difference in preferred habitat depth between the two species appears to have had very little influence on both retinal and pineal immunocytochemistry. It is concluded that the pineal organs of both species, at least during the austral summer, exhibit signs of being directly photo-sensitive.

Animals↗