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PubMed2000

[Limits and possibilities of 2D video analysis in evaluating physiological and pathological foot rolling motion in runners].

Three-dimensional movements of the lower extremities in support phases are usually evaluated with the help of video analysis. This analysis is mainly done two-dimensionally in a frontal and sagittal plane. Usually, the temporal ankle of the achilles tendon respectively rear foot are analysed in the frontal plane, the knee and upper ankle angle in the sagittal plane, because their values are made responsible for different sport injuries. However, so far a correlation between different injuries and biomechanical parameters could not be proven. Often, small changes in 2D video data are discussed without considering the reliability of this method of measurement. It was the aim of this study to evaluate these parameters in 2D video analyses (2D-VA) which characterize the support phases of the foot. A second goal was to find out whether a connection between these angles and chronic achillodynia can then be sensibly proven. 32 male test persons consisting of a control group (KO, n = 14) without injuries and a group with chronic achillodynia (AD, n = 18), have been examined with the test/retest method in weekly intervals. The biomechanical running analysis was done with the help of 2D-VA in the frontal and sagittal plane on a treadmill at a speed of 80% of the individual anaerobic threshold with different shoes. The test/retest variability was for all measuring points not at all satisfying. Both groups showed big mean variations in both shoes and minimal differences in the measured angles. Because of the poor capability of reproduction of the 2D-VA for angles in the frontal plane this measuring method is only usable with restrictions for the evaluation of the support phase.

Achilles Tendon↗
PubMed1976

Stretch reflex and servo action in a variety of human muscles.

1. In the long flexor of the thumb the latency of the stretch reflex and of other manifestations of servo action is some 45 msec, roughly double the latency of a finger jerk. 2. Tendon jerks are feeble or absent in the long flexor of the thumb even in subjects with brisk long-latency stretch reflexes in this muscle. This, and other facts, suggests that the nervous mechanism of the tendon jerk is different from that of the stretch reflex. 3. A muscle that has feeble tendon jerks may show a late component in the response to a tendon tap, with a latency similar to that of the long-latency stretch reflex. 4. On the hypothesis that the excess latency of the stretch reflex over that of a tendon jerk is because the stretch reflex employs a cortical rather than a spinal arc, the excess would be expected to be larger in magnitude for the long flexor of the big toe and smaller for the jaw closing muscles. This is confirmed, 5. An alternative hypothesis that the long latency of stretch reflexes in thumb and toe is because they are excited by slow-conducting afferents is made improbable by the finding that stretch reflexes with an equal or greater excess latency are also found in proximal arm muscles. 6. The long-latency stretch reflex in proximal muscles was seen most distinctly in a healthy subject who happened to have feeble or absent tendon jerks. In ordinary subjects there is often a large, short-latency, presumably spinal component of the stretch reflex in proximal muscles; and short-latency responses to halt and release are also seen, The significance of this spinal latency servo action in proximal muscles remains to be explored. 7. The Discussion argues that the available data on conduction time to and from the cerebral cortex are compatible with the hypothesis that the long-latency component of the stretch reflex uses a transcortical reflex arc, and that none of the experiments described in the present paper are inimical to this view.

Biomechanical Phenomena↗
PubMed2005

Cough: are children really different to adults?

Worldwide paediatricians advocate that children should be managed differently from adults. In this article, similarities and differences between children and adults related to cough are presented. Physiologically, the cough pathway is closely linked to the control of breathing (the central respiratory pattern generator). As respiratory control and associated reflexes undergo a maturation process, it is expected that the cough would likewise undergo developmental stages as well. Clinically, the 'big three' causes of chronic cough in adults (asthma, post-nasal drip and gastroesophageal reflux) are far less common causes of chronic cough in children. This has been repeatedly shown by different groups in both clinical and epidemiological studies. Therapeutically, some medications used empirically for cough in adults have little role in paediatrics. For example, anti-histamines (in particular H1 antagonists) recommended as a front-line empirical treatment of chronic cough in adults have no effect in paediatric cough. Instead it is associated with adverse reactions and toxicity. Similarly, codeine and its derivatives used widely for cough in adults are not efficacious in children and are contraindicated in young children. Corticosteroids, the other front-line empirical therapy recommended for adults, are also minimally (if at all) efficacious for treating non-specific cough in children. In summary, current data support that management guidelines for paediatric cough should be different to those in adults as the aetiological factors and treatment in children significantly differ to those in adults.

Journal Article↗
PubMed2005

Biological factors influencing tissue compartmentalization of trace metals in the deep-sea hydrothermal vent bivalve Bathymodiolus azoricus at geochemically distinct vent sites of the Mid-Atlantic Ridge.

In this study, we investigated on concentrations of trace metals (Al, Cd, Mn, Co, and Hg) in the hydrothermal bivalve Bathymodiolus azoricus, a dominant species at most vent sites along the Mid-Atlantic Ridge (MAR), and in its endosymbiont bacteria and commensal parasite Branchipolynoe seepensis. Comparison of our results with data from the literature on non-hydrothermal bivalves suggests lack of "extreme" uptake of trace metals by B. azoricus, except for Hg concentration which exceeded manyfold previously reported values. Mussels collected from three geochemically distinct vent sites, Menez Gwen, Lucky Strike, and Rainbow, along the MAR showed significant differences in tissue concentration of metals. Proportionality of metals in soft tissues of mussels reflected variation of water chemistry at different vents, which in turn conserved the order of trace metal prevalence in undiluted fluids. There were significant tissue-specific differences in trace metal compartmentalization for all metals investigated. Byssus thread contained the highest metal concentration among examined tissues, and thus it is suggested to be an important detoxification route. Size-dependent differences in metal concentrations were detected only for Hg, revealing a general trend of small mussels accumulating more metal than big mussels. Endosymbiont bacteria are shown to exclusively sequester Al from the host gill and contribute to removal of other toxic metals in mussels from Menez Gwen. The commensal parasite present in all mussels from Lucky Strike had higher tissue concentrations of Mn, Al, and Co than the host gill, unlike Cd and Hg which were considerably lower in the former, and thus its role in detoxification remains unclear. Bioaccumulation potential of vent bivalves and associated organisms are quantified as concentration factors and compared to make inferences on the putative role of the endosymbiont bacteria and the commensal parasite in detoxification of trace metals.

Animals↗
PubMed1998

Novel lectin-related proteins are major components in lima bean (Phaseolus lunatus L.) seeds.

The only component of the lectin-related protein family so far reported in Lima bean (Phaseolus lunatus L.) seeds is the minor seed lectin (LBL). In the morphotype Big Lima, we have isolated and characterised two abundant lectin-related seed proteins and the corresponding cDNA clones. The clones show 93.7% nucleotide identity and encode an arcelin-like (ARL) and an alpha-amylase inhibitor-like (AIL) protein. Not considering the signal peptides, ARL and AIL polypeptides contain 239 and 233 amino acids, respectively. Each polypeptide is present in the mature protein as two glycoforms. ARL subunits (43 and 46 kDa) make up oligomers of about 125 to 130 kDa whereas AIL subunits (40 and 42 kDa) oligomerise in dimers of about 88 to 100 kDa. cDNA clones encoding two isoforms of the less abundant Lima bean lectin were also isolated. In common bean (P. vulgaris) the lectin locus encodes the lectin and the lectin-related proteins alpha-amylase inhibitor and arcelin, all plant defence proteins. Our data indicate extensive evolution of the locus also in Lima bean.

Amino Acid Sequence↗
PubMed2000

Trends in hospital antimicrobial prescribing after 9 years of stewardship.

Trends in antibiotic prescribing in Grampian have been monitored prospectively for 11 years from 1986 using computerized ward stock lists and laboratory data relating to all in-patient and out-patient treatments in all Grampian hospitals. The main outcome measures were the number of antibiotics available for routine and restricted use, annual expenditure and defined daily doses (DDDs) of high expenditure antimicrobial agents. An antibiotic committee introduced a policy and formulary in the third year of the study which has had only limited success in controlling prescribing. This report updates the audit from 1992/3 to 1996/7. During this period 22 new antibiotics were considered for inclusion in the hospital formulary. Seventeen, including seven antiretroviral agents, were incorporated, all for restricted use only. Despite this, expenditure on antibiotics has more than trebled since 1986/7 and increased 50% since 1992/3, two-thirds of the latter increase being due to the use of new drugs, namely anti-HIV drugs, lipid amphotericin derivatives and teicoplanin. Big increases in the use of co-amoxiclav, acyclovir, ciprofloxacin and cefotaxime account for the remainder of the increased expenditure. There was an overall increase of 16.9% in DDDs between 1992/3 and 96/7 to 424.0 DDDs/1000 patient days (393.4 DDDs for antibacterials). These findings highlight the current difficulty in controlling prescribing budgets, the increasing use of antibiotics and the consequent increase of antimicrobial-resistant microorganisms.

Anti-Infective Agents↗
PubMed1996

Births by younger and older mothers in a population with late and regulated childbearing: Finland 1991.

PURPOSES: The aims of this study were: first, to ascertain the characteristics of younger and older mothers in the Finnish population; second, to assess the health conditions pertaining to births and newborns according to maternal age groups. METHODS: The data, 26,373 primiparous and 38,895 multiparous women, came from the 1991 nationwide Finnish birth register, and was completed using death and education registers. The younger (< 18 and 18-19 year olds) and older (35-39 and 40 and over) mothers were compared to 20-34 year olds. Infant outcomes were studied by adjusting for mothers' social and obstetric background characteristics by using stepwise logistic regression. RESULTS: Births were rare among women younger than 18 years or 40 years or older. Younger primiparous mothers (less than 20 years) were less often married, more often had a lower social class background, and tended to live in Northern Finland and used antenatal care somewhat less. Their pregnancies, giving birth and infant outcomes were similar to those of 20-34 years old mothers. Most older mothers were women having their families late, rather than having big families. Older primiparas (35 years or older) were less likely to be married, were more often highly educated and lived in urban areas and in the most southern county. Older mothers had more problems during pregnancy and labor, and their infant outcomes were worse. CONCLUSIONS: Our study supports the notion that for young mothers giving birth is a social rather than a medical problem, whereas the reverse is true for older mothers. However, perinatal results for most older mothers are good.

Adolescent↗
PubMed1998

DNA adduct level induced by 2-amino-3,4-dimethylimidazo[4,5-f]-quinoline in Big Blue mice does not correlate with mutagenicity.

In previous experiments we analyzed the mutant frequency (MF) and mutational types in various organs of lacI transgenic mice which were fed a diet containing 300 p.p.m. 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQ), a food-borne mutagen/carcinogen. To clarify the relationships between mutational type and adduct molecular species and between adduct level and MF we analyzed adducts in the same DNA samples. The DNA adduct in the liver, heart, colon, forestomach and bone marrow was determined by the modified intensification method of 32P-post-labeling at time points 1, 4 and 12 weeks. Only a single spot corresponding to N2-(deoxyguanosin-8-yl)MeIQ 5'-monophosphate was detected in DNA from all organs at all time points examined, with a recovery of 48%. The difference in mutation type between bone marrow and other organs detected in the previous experiment was not explained by adduct molecular species. At 4 and 12 weeks administration the adduct levels were highest in the liver and then heart, colon, forestomach and bone marrow in decreasing order, with values of 28.3, 8.4, 3.3, 1.3 and 0.4 molecule/10(7) nucleotides at 12 weeks. Based on our previously reported data, lacI MF was highest in the colon and those in the liver, bone marrow and forestomach were 10-60% of that of the colon; no increase in MF was detected in the heart, where no DNA replication is expected except for vascular endothelial cells. There was no direct relationship between MF and adduct level. The MF may be the product of adduct level and cell proliferation rate.

Animals↗
PubMed1992

Immunocytochemical localization of luteinizing hormone-releasing hormone (LHRH) in the nervus terminalis and brain of the big brown bat, Eptesicus fuscus.

Little is known about the immunohistochemistry of the nervous system in bats. This is particularly true of the nervus terminalis, which exerts strong influence on the reproductive system during ontogeny and in the adult. Luteinizing hormone-releasing hormone (LHRH) was visualized immunocytochemically in the nervus terminalis and brain of juvenile and adult big brown bats (Eptesicus fuscus). The peripheral LHRH-immunoreactive (ir) cells and fibers (nervus terminalis) are dispersed along the basal surface of the forebrain from the olfactory bulbs to the prepiriform cortex and the interpeduncular fossa. A concentration of peripheral LHRH-ir perikarya and fibers was found at the caudalmost part of the olfactory bulbs, near the medioventral forebrain sulcus; obviously these cells mediate between the bulbs and the remaining forebrain. Within the central nervous system (CNS), LHRH-ir perikarya and fibers were distributed throughout the olfactory tubercle, diagonal band, preoptic area, suprachiasmatic and supraoptic nuclei, the bed nuclei of stria terminalis and stria medullaris, the anterior lateral and posterior hypothalamus, and the tuber cinereum. The highest concentration of cells was found within the arcuate nucleus. Fibers were most concentrated within the median eminence, infundibular stalk, and the medial habenula. The data obtained suggest that this distribution of LHRH immunoreactivity may be characteristic for microchiropteran (insectivorous) bats. The strong projections of LHRH-containing nuclei in the basal forebrain (including the arcuate nucleus) to the habenula, may indicate close functional contact between these brain areas via feedback loops, which could be important for the processing of thermal and other environmental stimuli correlated with hibernation.

Animals↗
PubMed2002

Interaction between excitation and inhibition affects frequency tuning curve, response size and latency of neurons in the auditory cortex of the big brown bat, Eptesicus fuscus.

Neurons in the auditory cortex (AC) receive convergent excitatory and inhibitory inputs from the lower auditory nuclei. Interaction between these two opposing inputs shapes different response properties of AC neurons. In this study, we examined how this interaction might affect the frequency tuning curves (FTCs), number of impulses and latency of AC neurons in the big brown bat, Eptesicus fuscus, using a probe (excitatory tone) and a masker (inhibitory tone) under different stimulation conditions. Excitatory FTCs of AC neurons were either V-shaped, closed (i.e. upper threshold) or double-peaked. Inhibitory FTCs were obtained either at both flanks or only at the low or high flank of excitatory FTCs. Application of bicuculline, an antagonist for gamma-aminobutyric acid A receptors, produced expansion of excitatory FTCs into predrug inhibitory FTCs. Inhibition of probe-elicited responses occurred when a masker was presented at certain intertone intervals. Maximal inhibition typically took place when a masker was presented within 4 ms prior to the probe. During maximal inhibition, a neuron had the minimal number of impulses and the longest response latency. Inhibition became stronger with increasing masker intensity but became weaker with increasing intertone interval. Biological significance of these data is discussed.

Acoustic Stimulation↗
PubMed1995

Trypanosoma cruzi induces endothelin release from endothelial cells.

The potential role of endothelin-1 (ET-1) in the pathogenesis of focal microvascular spasm, previously implicated in the etiology of Chagas' cardiomyopathy, was investigated. There was an increase in ET-1 in the supernatants of Trypanosoma cruzi--infected human umbilical vein endothelial cells (HUVEC). Infection of HUVEC and vascular smooth muscle cells had no effect on the synthesis of transforming growth factor-beta, which induces ET-1 synthesis. Bioassay studies of isolated rat aortic rings revealed that the increases in ET-1 production were associated with augmented contractile responses, which were significantly attenuated by preincubation with the ETA receptor antagonist, BQ-123. When big ET was incubated with the parasite, there was no conversion of the precursor to the active hormone (ET-1), demonstrating that the parasite did not possess the necessary converting enzyme. These observations suggest the potential importance of ET-1 in the etiology of the microvascular spasm associated with Chagas' disease.

Animals↗
PubMed1993

Hormonal changes with lower body negative pressure on the 6th day in microgravity in one cosmonaut.

We measured volume regulating and stress hormones (AVP, aldosterone, ANP, c-GMP, angiotensin II, PRA, epinephrine, norepinephrine, ACTH, cortisol) in venous blood twice during a lower body negative pressure (LBNP) maneuver in one cosmonaut (31 years, 75 kg, 180 cm) preflight (supine), inflight (6th d in orbit), and on the 4th d (supine) after a 10-d flight. Antecubital blood was taken at the beginning (3 min: "a") and after ceasing (2 min: "b") 40 min LBNP (-15/-30/-35 mm Hg for 15/15/10 min). At the beginning of LBNP, no big changes of resting hormone levels are to be expected. Comparison of "a" values: Inflight, there was a 4-5-fold increase in vasopressin and epinephrine, a slight increase in aldosterone, ANP, norepinephrine, cortisol and ACTH, and a decrease in PRA levels. Postflight, vasopressin was almost as much increased as inflight, and aldosterone and ANP levels were higher than pre- or inflight. PRA, epinephrine, norepinephrine, and cortisol were moderately increased, whereas ACTH and angiotensin II were diminished. Comparison of "b" to "a" values (2 min after LBNP to 3 min intra-LBNP): Preflight, ANP, PRA, and epinephrine rose more than 100%. The inflight response was higher for aldosterone but lower for all other volume active hormones. Postflight, the increase in PRA was pronounced, whereas little change occurred in other hormones. Cortisol and ACTH fell similarly during LBNP under all conditions. In summary, the data provide evidence that not only the endocrine status but also the neuroendocrine responsiveness to stimulation; i.e., the hormone response during cardiovascular load, are altered by the stay in microgravity and readaptation to normal conditions.

Adaptation, Physiological↗
PubMed2003

Cyclic AMP signalling during mammalian sperm capacitation--still largely terra incognita.

Cyclic AMP is known to play a major role in intracellular signalling during mammalian sperm capacitation. However, despite much research, many of the molecular details of cyclic AMP's involvement remain obscure. In this review, I discuss the following aspects, presenting some original data as illustration where relevant. With respect to cyclic AMP synthesis, uncertainties exist as to the number of forms of adenylyl cyclase that are present in the spermatozoon, whether they are cytosolic or bound to subcellular structures, and which physiological effectors they respond to (e.g. bicarbonate, Ca2+, or receptor-coupled G-proteins). While net intracellular levels of cyclic AMP in spermatozoa depend upon the relative activities of adenylyl cyclase and phosphodiesterase, there are wide between-sample variations within species, both in basal levels and in levels attained after activation of the cyclase (e.g. after sperm treatment with bicarbonate). Moreover, minor changes in bulk cyclic AMP levels can result in large changes in cyclic AMP-dependent functions. Finally, while cyclic AMP levels respond very rapidly to sperm treatment by effectors such as bicarbonate and Ca2+ (key components of capacitating media), there are big discrepancies between the rates of functional response. For example, enhancement of motility and collapse of phospholipid asymmetry take place within a few minutes, whereas more than 1 h of exposure to capacitating conditions is needed for cyclic AMP-dependent protein tyrosine phosphorylation to become detectable or for the sperm population to attain a capacitated state.

Adenylyl Cyclases↗
PubMed1998

[Prevalence of glucose intolerance in Japan--from the National Circulatory Disorders Basic Survey, 1990].

The prevalence of glucose intolerance was surveyed in 8,063 people over 30 years old from the general population of Japan. The data used in the analysis were from the Fourth National Circulatory Disorders Basic Survey, which was conducted in 1990. Survey items included history of diabetes mellitus, body mass index (BMI) and daily life activity. Blood and urine were also examined, and the blood glucose levels, presence or absence of sugar in urine, and levels of glycohemoglobin (HbA1c) were determined. Glucose intolerance was identified from the blood glucose level, HbA1c level and history of diabetes mellitus. The frequency of glucose intolerance was 8.6% in all subjects (11.9% in men and 6.3% in women). The frequency was higher in older people: 1.7 times higher in men over 65 years old and 2.5 times higher in women over 65 years old. Among people over 40 years old, glucose intolerance was significantly more prevalent in men than in women. It was also significantly more prevalent in men living in big cities than in men living in rural areas. Among obese male subjects and men with a low level of activity in daily life, the frequency of glucose intolerance was higher than in normal male subjects. The level of activity in daily life tended to be lower for people living in big cities than for those in rural areas. The results suggest that the prevalence of glucose intolerance depends on the environment in which people live. The results also indicate that raising the level of activities in daily life might help prevent diabetes mellitus.

Activities of Daily Living↗
PubMed1992

Affinity enhancement of complementary peptide recognition.

A peptide hydropathically complementary to Big Endothelin [Big ET] residues 16-29 has been synthesized in a multimeric form starting from an octadentate polylysine core, essentially in a way similar to the procedure used for the production of multiple antigenic peptides [MAP's]. Interaction between the multimeric complementary peptide [8 delta ET] and the Big ET fragment 16-32 containing the target complementary region, also synthesized in a multimeric form [8ET], was evaluated by analytical high performance affinity chromatography and solid phase binding assays. While the binding interaction between the monomerics peptide pair was in the micromolar range, the recognition between the corresponding multimeric form was characterized by enhanced binding affinity of at least two orders of magnitude. In solution, complex formation between multimeric complementary peptide and target Big ET sequence in the monomeric and multimeric form was accompanied by precipitation at concentrations higher than 0.5 mg/mL and 0.1 mg/mL, respectively. Polyclonal antibodies raised against the multimeric target sequence recognized multimeric and monomeric ET target sequences with binding affinities similar to binding affinities exhibited by the multimeric complementary peptide. Multimerization of hydropathically complementary peptides could provide an improved opportunity to measure and thus probe quantitative binding properties of complementary peptides.

Amino Acid Sequence↗
PubMed1986

The molecular genetics of components of complement.

Rapid progress has been made in establishing linkages and in chromosome allocation of the genes of some 9 complement components. In the MHC, C2, Factor B, and two C4 or C4 related genes have been placed in some detail in both man and mouse. The gene coding for the cytochrome P-450 21-hydroxylase has been shown to be duplicated and immediately 3' to the two C4 genes, though it appears to be functionally and structurally unrelated to the complement components. Thus six genes have been mapped to this region where particular haplotypes are associated with increased susceptibility to a number of diseases, some of which are autoimmune in character. The complete gene structure of Factor B has been solved in man and rapid progress is being made with the C2 and C4 genes. The structural basis of the polymorphisms of these genes is being established. In C4, the polymorphism is exceptionally complex with varying numbers of loci and probably more than 50 allotypes occurring in man. A structural basis has also been found for the big differences in the biological activity of some of the C4 allotypes in man. Apart from the genes in the MHC, linkage has been found between the genes coding for C4bp, CR1, and Factor H. Remarkably there are sequence homologies between these proteins and C2 and Factor B, probably related to the ability to bind to one or other of the structurally similar proteins C3b and C4b. The complete cDNA sequences of C3 and C4 in mouse and man have given much information on the many posttranslational modifications of these proteins. A partial structure has been obtained for the C3 gene and the homology shown between C3, C4, C5, alpha 2-macroglobulin, and pregnancy zone protein. Although the amount of detailed information in the molecular genetics of complement components is accumulating rapidly, there appears to be a reasonable prospect that linkages and homologies will classify the data into a comprehensible form.

Alleles↗
PubMed2003

Spectral signature of cosmological infall of gas around the first quasars.

Recent observations have shown that, only a billion years after the Big Bang, the Universe was already lit up by bright quasars fuelled by the infall of gas onto supermassive black holes. The masses of these early black holes are inferred from their luminosities to be >10(9) solar masses (M(O)), which is a difficult theoretical challenge to explain. Like nearby quasars, the early objects could have formed in the central cores of massive host galaxies. The formation of these hosts could be explained if, like local large galaxies, they were assembled gravitationally inside massive (> 10(12) M(O)) haloes of dark matter. There has hitherto been no observational evidence for the presence of these massive hosts or their surrounding haloes. Here we show that the cosmic gas surrounding each halo must respond to its strong gravitational pull, where absorption by the infalling hydrogen produces a distinct spectral signature. That signature can be seen in recent data.

Journal Article↗
PubMed2005

[Fragmentation process of wetland landscape in watersheds of Sanjiang Plain, China].

The Sanjiang Plain is the largest fresh water wetland distribution area in China and the center of waterfowls breeding and habitat area in Asia, but over the past 50 years, more than 73% of its wetland had lost because of agricultural development, and as a result, the wetland biodiversity declines dramatically, and the remnant wetlands are in a very fragment state. Based on historical maps, remote sensing data and GIS techniques, this paper selected two watersheds to analyze their wetland landscape fragmentation process during 1950-2000. It was indicated that land reclamation resulted in a decrease of 98% wetland corridors in Qixing River, 90% in Naoli River, 87% in the middle reach of Bielahong River, and 94% in the lower reach of Bielahong River; The amount of isolated wetlands in watershed increased dramatically; The maximum patch areas of wetland decreased by 92.6% in Naoli River watershed and 74.6% in Bielahong River watershed, and the mean wetland patch area in the two watersheds decreased by 99%. Before 1983, the wetland landscape was in an extensive area distribution state (the index of patch density was < 0.1), but after 1983, it fragmented dramatically, with the index of patch density larger than 1.5. The shape fragmentation indices of wetland decreased from 1950 to 2000, indicating a very big change in wetland patch shapes in the watersheds. The area fragmentation indices of wetland also increased from 1950 to 2000, especially after 1983, showing that the wetlands were in a serious fragmentation state. The wetland landscape fragmentation changed from a landmass and island model to a satellite model, and finally to a completely isolated model, which indicated the great changes in spatial structure of wetland in the Sanjiang Plain.

Agriculture↗