Showing papers by "University of Turku published in 1986"

River dynamics and the diversity of Amazon lowland forest

Abstract: We suggest here that large-scale natural forest disturbance and primary succession in the lowland rainforests of the Peruvian Amazon is caused by lateral erosion and channel changes of meandering rivers. Our results indicate that in the upper Amazon region, primary succession on newly deposited riverine soils is a major mode of forest regeneration. Landsat imagery analyses show that 26.6% of the modern lowland forest has characteristics of recent erosional and depositional activity; 12.0% of the Peruvian lowland forest is in successional stages along rivers. This successional development is used to classify the western Amazon rainforests according to their geomorphological erosion–deposition pattern. We also propose that by causing high site turnover, disturbance and variation in forest structure, the river dynamics may be a major factor creating and maintaining the high between-habitat (β-type) species diversity characterizing the upper Amazon1.

Survival and cause of death in Alzheimer's disease and multi-infarct dementia.

Abstract: Survival and causes of death of 218 patients with Alzheimer's disease (AD) and of 115 patients with multi-infarct dementia (MID) were examined. The patients were originally found in a community-based epidemiological survey of dementia, and all patients with AD or MID alive on the prevalence day were included. The 6-years survival rate for AD was 21.1% vs. the expected rate 48.5%, that for MID 11.9% vs. 45.2% expected. A comparison of relative survival rates suggested that MID carries a less favorable survival prognosis than AD. The mean durations were: AD 5.7 years and MID 5.2 years; median duration being 5 years in both diseases. The excess mortality in both AD and MID was independent of age. In AD, the survival rate decreased with increasing severity of dementia, while in MID the mortality was the same regardless of the severity of the dementia. The dementia disorder was the underlying cause of death in 68% of AD patients, and in 38% of MID patients, bronchopneumonia being the most frequent immediate cause of death in both groups. As a cause of death, acute cerebrovascular accidents occurred more often in MID patients than in the general population of comparable age. Malignant diseases were less frequent as a cause of death in both dementia groups than in the general population.

The Book of L

Abstract: Investigations into Drosophila Wing Development - Results from a Lindenmayer Model.- Fibonacci Words - A Survey.- Planar Map Generation by Parallel Binary Fission/Fusion Grammars.- Modular Trellises.- A New Proof for the DOL Sequence Equivalence Problem and its Implications.- On Compound Lindenmayer Systems.- Graph Grammars with Application Conditions.- The ETOL Hierarchy is in the OI Hierarchy.- Polyhedral Cell Shapes.- On Cyclically Overlap-Free Words in Binary Alphabets.- The Theoretical Basis of the Transplantation Experiment.- Fixed and Stationary ?-Words and ?-Languages.- DOL Schemes and Recurrent Words.- Stochastic OL Systems and Formal Power Series.- Complexity of L-Systems.- Compartmental Hybrid State Production-Diffusion Systems with Application to Prestalk-Prespore Pattern Regulation in Cellular Slime Molds.- Hierarchical Aspects of Plant Development.- Rule Trees Represent Derivations in Edge Replacement Systems.- Languages Defined by Indian Parallel Systems.- L Systems and NLOG-Reductions.- The Parikh-Boundedness of ETOL Languages of Finite Index.- Computer Networks with Compact Routing Tables.- Unconventional Leaves.- A Uniform Model for the Growth of Biological Organisms: Cooperating Sequential Processes.- Graph Technology Applied to a Software Project.- Some Systems for Map Generation.- A Programming Language for Lindenmayer Systems.- A Note on Significance of Cellular Interaction in L-System.- EOL Grammars and Search Trees.- Variation in Inflorescence Structure in Cotoneaster Franchetti.- Partial Path Groups and Parallel Graph Contractions.- When L was Young.- Equivalence Problems for Regular Sets of Word Morphisms.- Parentheses Grammars and Lindenmayer Grammars.- Array Languages and Lindenmayer Systems - A Survey.- Symmetric Distributed Termination.- Development, Growth and Time.- On the Set of all Subgraphs of the Graphs in a Boundary NLC Graph Language.- Graph-Controlled Systems - An Extension of OL Systems.

Peritubular myoid cells of human and rat testis are smooth muscle cells that contain desmin-type intermediate filaments.

Abstract: We studied the cytoskeletal composition of human and rat testicular myoid cells by using immunofluorescence microscopy with polyclonal and monoclonal antibodies. In adult human and rat testis, the peritubular myoid cell layer was brightly positive for desmin, the muscle type of intermediate filament protein, and a faint reaction was also seen with antibodies to vimentin, the intermediate filament protein of fibroblasts and diverse other mesenchymal cells. The desmin-positive myoid cell layer could already be identified in newborn rat testis but was more compact in appearance 23 days after birth. Both squash preparations and cultured cells from adult rat seminiferous tubules revealed distinct cell populations positive for desmin. The adult myoid cells of both species also showed a strong reaction with antibodies to myosin and p230, a nonerythroid avian alpha-spectrin analogue. The immunostaining results could be confirmed by the western blotting technique: Experiments with isolated seminiferous tubules showed a specific reaction with a 55,000-dalton and a 58,000-dalton polypeptide when desmin and vimentin antibodies were used, respectively. The present results show that the peritubular myoid cells are genuine smooth muscle cells with desmin-type intermediate filament cytoskeleton and suggest that these cells can be identified by this feature before their ultrastructural maturation.

Cell interactions during the seminiferous epithelial cycle.

Abstract: Publisher Summary This chapter discusses the cell interactions during the seminiferous epithelial cycle. Spermatozoa belong to the most differentiated cells of the body. Their special features are a haploid number of chromosomes, a tightly packed inactive form of the chromatin, a small amount of cytoplasm, and an ability of independent movement by a flagellum. The development of spermatozoa in the seminiferous epithelium includes three main phases: (1) spermatogonial multiplication, (2) meiosis, and (3) spermiogenesis. Cells in these phases are called spermatogonia, spermatocytes, and spermatids, respectively. The stage-dependent variation of the hormone responses in the seminiferous epithelium strongly suggests an existence of local paracrine regulation and cell interaction mechanisms in the seminiferous epithelium, that are dependent on spermatogenic cells associated with the Sertoli cells at each stage of the cycle of the seminiferous epithelium. The nature of this interaction is obscure; however some advances have been made. The secretion of a proteolytic enzyme, urokinase-type plasminogen activator, seems to be dependent on both cellular and hormonal regulation in the seminiferous epithelium. Testicular GnRH-like factors and proopiomelanocortin-derived peptides may play a role in seminiferous tubule-Leydig cell interaction. In the seminiferous epithelium, a Sertoli cell-derived growth factor is suggested to have a role in local regulation together with other factors, such as meiosis-inducing and -preventing substances, a somatomedin-like compound, and the spermatogonial chalone.

Periapical actinomycosis: a follow-up study of 16 surgically treated cases.

Abstract: Clinical features of 16 immunocytochemically verified and surgically treated cases of periapical actinomycosis were evaluated. A. israelii was demonstrated in 13, A. propionica in 10, and A. naeslundii in 6 biopsy specimens. More than one of these species were present in 9 lesions. All cases had a long and complicated clinical history accompanied by fistulation and destruction of cortical bone plates. During a mean follow-up period of 28 months after periapical surgery, only 1 clear failure was found. The results indicated that periapical actinomycosis is more common than previously believed and that these infections can be controlled by ordinary periapical surgery.

Macrophages in the interstitial tissue of the rat testis.

Abstract: Macrophages were identified in the intertubular tissue of the rat testis by loading animals with a particulate vital dye (trypan blue or India ink) and by localizing immunocytochemically a macrophage membrane antigen (MRC W3/25). Leydig cells were identified by the histochemical staining reaction for 3β-hydroxysteroid dehydrogenase activity and by a monoclonal antibody. Macrophages were scattered in the interstitial tissue closely attached to and mixed with the Leydig cells. They were never found in the seminiferous tubules. The macrophages comprised about 25% of all the cells in the interstitium. Double staining with a vital dye and a marker antibody showed that all the phagocytosing cells were macrophages and that the Leydig cells did not take up vital dyes. Double staining for the demonstration of the 3β-hydroxysteroid dehydrogenase activity and the macrophage antigen likewise revealed two distinctly different cell populations. Crude Leydig cell preparations obtained by collagenase treatment of the testis contained macrophages (12–14%). Macrophages were present throughout the postnatal prepuberal development of the testis. Their density was increased in the cryptorchid and irradiated testis.

Oral health of patients with insulin-dependent diabetes mellitus.

Abstract: Oral health, the amount of salivary Streptococcus mutans and lactobacilli, and the flow rate, pH and buffer capacity of paraffin-stimulated whole saliva were analyzed in 35 adult diabetic patients and their age- and sex-matched non-diabetic, clinically healthy controls. All patients had insulin-dependent diabetes (IDDM) with a mean (+/- SD) duration of 14.0 +/- 9.1 yr. The prevalence of dental caries was as high in the diabetic group as in the controls but the past caries experience was remarkably lower in those individuals whose diabetes had started at a very early age (less than or equal to 7 yr). In agreement with the clinical data, the salivary levels of cariogenic microorganisms were of the same order of magnitude in both study groups. However, the relative proportion of S. mutans from the total cultivable aerobic microflora was significantly higher (P less than 0.01) in diabetics compared to the controls. The other studied salivary parameters did not differ between the groups. Remarkable individual differences were observed in the correlation between glucose levels of blood and whole saliva among diabetics. In spite of the noncariogenic dietary habits, the adult diabetic patients seem to be at least as susceptible to dental caries as non-diabetics, probably due to the leakage of glucose from blood into the oral cavity.

Influence of cellular DNA content on survival in differentiated thyroid cancer.

Abstract: Cellular DNA content was measured using a novel flow cytometric method to analyze paraffin-embedded tissue blocks from 125 patients with differentiated thyroid cancer. DNA aneuploidy was found in 20 (24%) of the 82 papillary, 20 (56%) of the 36 follicular, and in four (57%) of the seven medullary carcinomas. Aneuploidy was found to be more common in the elderly (P less than 0.002), in moderately and poorly differentiated carcinomas (P less than 0.004), and in tumors infiltrating beyond the thyroid capsule (P less than 0.03). Patients with an aneuploid tumor had less favorable cumulative survival (P less than 0.0001) than patients with diploid cancer. However, in papillary and follicular carcinomas, multivariate analysis using stepwise Cox model showed age at diagnosis, follicular type, and tumor invasion beyond the thyroid capsule to be more important independent prognostic factors. Increasing probability of DNA aneuploidy with increasing age explains partially why prognosis of differentiated thyroid carcinoma is poor in older patients.

Immunoglobulins and Innate Antimicrobial Factors in Whole Saliva of Patients with Insulin-dependent Diabetes Mellitus

Abstract: We analyzed the flow rate and composition of paraffin-stimulated whole saliva samples from 35 adult diabetic patients and their age- and sex-matched, non-diabetic, clinically healthy controls. All patients had insulin-dependent diabetes (IDDM) with a mean (± S.D.) duration of 14.0 ± 9.1 years. The saliva analysis included the quantitation of total protein, amylase, immunoglobulins (isotypes A, G, and M), and the non-antibody, innate antimicrobial factors (lysozyme, lactoferrin, salivary peroxidase, myeloperoxidase, thiocyanate, and hypothiocyanite). The whole saliva samples from diabetic patients had significantly higher amounts of IgA (p < 0.001) and IgG (p < 0.05) than did the controls. No differences between the study groups were observed in flow rate, protein content, amylase activity, or IgM. The levels of innate defense factors were similar in both study groups except for salivary peroxidase, which was higher (p < 0.02) among diabetics than among controls. Our results indicate that the antimicrobial...

Taxol-induced neuropathy: chronic effects of local injection

Abstract: The long-term neurotoxic effects of taxol, a compound known to promote microtubule protein polymerization, injected subepineurially into rat sciatic nerve were studied up to 10 weeks post-injection. At the site of injection, taxol caused local axonal reactions and degeneration which were causally related to the slow progressive accumulation of microtubules and other axoplasmic constituents. This culminated in the appearance of giant axonal spheroids and profiles similar to the retraction bulbs of Wallerian degeneration. From these axonal bulbs, many of which arose at nodes of Ranvier, groups of regenerating sprouts emanated. During the acute phase of taxol neurotoxicity, some swollen axons were divested of their myelin sheaths and remained demyelinated for many weeks. After 4 weeks, remyelination was apparent along some fibres. In addition to the accumulation of profiles usually associated with retraction bulbs, there was a vast increase in microtubules, some of which were aligned in concentric rings and formed channels for mitochondria. Microtubule anomalies were also visualized in distal portions of affected fibres and in regenerating sprouts. In contrast, Schwann cells displayed microtubule abnormalities only at the site of the lesion where excessive microtubule polymerization caused the displacement of ribosomes from rough endoplasmic reticulum. Distally, Schwann cells were essentially normal. Axonal depletion and regenerating sprouts were noted further downstream in the tibial nerve, and the gastrocnemius muscle showed changes similar to denervation atrophy. These results extend previous observations by demonstrating chronic, reparatory and reversible phenomena, the implications of which are discussedvis a vis axoplasmic transport and nerve regeneration.

Outbreak of cryptosporidiosis among veterinary students.

Abstract: We describe an outbreak of human cryptosporidiosis in 5 veterinary students in contact with experimentally infected calves. All persons experienced symptoms of gastroenteritis, with the main complaint of diarrhoea lasting for 1–13 days. The persons recovered spontaneously; one was hospitalized for 10 days. The diagnosis was based on the demonstration of Cryptosporidium oocysts from stools by the smear method and the formalin-ether concentration method, both combined with the acid-fast staining technique. Both methods gave almost equal results. The role of Cryptosporidium as an occupational risk is discussed.

The Equivalence of Finite Valued Transducers (on HDTOL Languages) is Decidable

Abstract: We show a generalization of the Ehrenfeucht Conjecture: For every language there exists a (finite) test set with respect to normalized k-valued finite transducers with bounded number of states. Further, we show that for each HDTOL language such a test set can be found effectively. As a corollary we solve an open problem by Gurari and Ibarra: The equivalence problem for finite valued finite transducers is decidable. This is the first time the equivalence problem is shown to be decidable for a larger class of multivalued transducers.

The fate of acrosomal staining during the acrosome reaction of human spermatozoa as revealed by a monoclonal antibody and PNA-lectin

Abstract: A monoclonal anti-human sperm antibody, raised against an acrosomal antigen and indicated to recognize in boar sperm the serine protease, acrosin, stained in human spermatozoa a 50 Kd antigen and several others in the region 24-34 Kd by immunoblotting. The 50 Kd band and the region of 30-34 Kd showed proteolytic activity by zymographic enzyme detection. The fate of the antigen was studied in the acrosome reaction induced by the calcium ionophore A23187. In control incubations 69.5 +/- 14.2% (mean +/- SD) of the spermatozoa had intact acrosomal staining according to indirect immunofluorescence using this antibody whereas in acrosome-reacted samples only 21.0 +/- 2.0% of the sperm were stained. Another marker for the acrosome, peanut agglutinin-lectin (PNA), was used to detect the acrosome with similar results. Acrosome reactions were verified by electron microscopy. The present results indicate that the corresponding antigen, evidently acrosin, and PNA-positive material are liberated during the acrosome reaction which suggests that they are not bound to the inner acrosomal membrane but are components of the acrosomal matrix.

The site of settlement indicates commensalism between bluemussel and its epibiont.

Abstract: The site of settlement of barnacles (Balanus improvisus) attached on shells of bluemussels (Mytilus edulis) was mapped from a sample of mussels collected in the Baltic Sea. Most barnacles had settled near the siphonal apertures of the mussel. An experiment was made to measure the disadvantages and advantages that living in close association brings to barnacles and mussels. The barnacles on shells of living mussels were shown to grow significantly faster than those on empty mussel shells. Presence of barnacles had no effects on growth of mussels. The two-species association under study was demonstrated to be a case of commensalism.

Comparison of five interocclusal recording materials.

Abstract: The initial resistance of interocclusal recording materials to closure changed from 0.5 N to 13.8 N, and a rapid rise in the working time was seen in all elastomers. The resistance exhibited by wax at 60 °C was about 7 N. The volumetric contraction of elastomers in polymerization was clinically slight. The dimensional stability of rigid materials, acrylic resin, and zinc oxide pastes was good. Elastomers maintained their reliability for a relatively long time when stored in a tightly sealed plastic bag.

Pollen seasons: forecasts of the most important allergenic plants in Finland.

Abstract: Occurrence of airborne pollen in Finland has been studied for 10 years in Turku (southern Finland), 8 years in Oulu, 4 years in Kuopio (central Finland) and 7 years at Kevo (northern Lapland). Observations on the pollen seasons of alder, birch, grasses and mugwort are presented. All these pollens occur in south and mid- Finland in quantities capable of causing allergy symptoms. Except for birch pollen, allergenic pollens occur in far lower concentrations than in central Europe. In northern Lapland only birch and pine pollen concentrations are high. Pollens may occur without signs of local flowering when there are southerly winds. This finding suggests that long-distance transport is an essential contributing factor to the occurrence of pollens. There are wide year-to-year variations in the start of pollen seasons and the quantities of pollens. The variations in the start of birch and grass pollen seasons could very much depend on the mean temperature in April. However, a forecasting model based on this and other spring-time temperature parameters often fails to give sufficiently accurate forecasts.

Effect of occlusal adjustment on mandibular dysfunction. A double-blind study.

Abstract: A group of headache patients who also had many signs and symptoms of mandibular dysfunction were randomly assigned to treatment and placebo groups. All 48 patients in the treatment group received occlusal adjustment and 19 of them also splint therapy. In the placebo group all 43 patients received mock adjustment. The changes in symptoms and signs of mandibular dysfunction were evaluated after 8 months in the treatment group and after 4 months in the placebo group, in a double-blind design. Placebo treatment and real treatment were equally effective in relieving symptoms of mandibular dysfunction, but there was significantly more reduction in signs of dysfunction in the treatment group than in the placebo group. When tested statistically, this reduction appeared to be independent of the use of splints as an aid to treatment. It can be concluded that the elimination of occlusal disturbances was an effective treatment for mandibular dysfunction.

Involvement of the audiovestibular system in multiple sclerosis. An otoneurologic and audiologic study

Abstract: This study was performed on a material of 70 patients, who fulfilled the criteria of definitive MS. All the patients were examined by an otologist, a neurologist and a neuro-ophthalmologist. A wide range of audiologic and otoneurologic tests were used to obtain a good understanding of the respective disorders in MS, to gain a better knowledge of the role of otology in MS, to correlate the results with the clinical findings in order to find the most useful tests to detect MS lesions and to describe pathophysiologic aspects of central lesions using MS as a model. The material consisted of MS cases representing mild or moderate stages of disability (Hyllested classification 1.-4); 32 belonged to Hyllested group 1., 19 to group 2., 7 to group 3. and 12 to group 4. The age and sex distribution were similar with materials described earlier, as were most of the clinical neurologic findings. The material can thus be considered representative. The neuro-ophthalmologic examination served to rule out causes other than MS for abnormalities observed in the tests. Besides the clinical neurologic and otoneurologic evaluation a number of additional tests were performed. The ENG tests consisted of registration for spontaneous and positional nystagmus, of smooth pursuit and saccadic eye movements, optokinetic nystagmus and caloric reactions. The audiologic evaluation was based on the following tests: pure tone audiograms, speech reception thresholds, discrimination scores, filtered speech test, stapedius reflex thresholds, stapedius reflex decay and auditory brainstem responses. The clinical otologic examination revealed little abnormalities, which is well in accordance with the pathophysiology of MS. In addition the clinical examination ruled out peripheral lesions as reasons for observed abnormalities. Numerous abnormalities were found during the otoneurologic examination of the cranial nerves. The amount of abnormal findings in the otoneurologic examination were surprisingly high: only one patient exhibited normal results in all the tests used. The abnormalities most often encountered were those of smooth pursuit (96%), followed by saccadic eye movements (76%), optokinetic nystagmus (53 %), and abnormalities in the caloric reactions such as dysrhythmia (40%) and defective visual suppression of the nystagmus (43%). When comparing the results obtained with ENG with those of clinical findings seen during the neuro-ophthalmologic examination, a good intercorrelation was found. Yet, in many ENG tests a number of cases with subclinical abnormalities only, were observed, which stresses the importance of exact and objective methods for the registration of eye movements.(ABSTRACT TRUNCATED AT 400 WORDS)

Viral findings in children under the age of two years with expiratory difficulties.

Abstract: Viral findings were prospectively studied in lower respiratory tract infections in small children with and without expiratory difficulties. On first admission, a viral aetiology was found in 71 of 127 children (56%). On re-admission, a viral etiology was found in only two of 31 cases (6%). Respiratory syncytial viruses (RSV) were responsible for 71% of the cases with viral diagnoses. A recently-developed method for the direct detection of viral antigens in nasopharyngeal specimens by radio-immunoassay was more sensitive than complement fixation serology, especially in patients aged less than six months. Viral diagnosis was reached using this new method alone in 43% of infections caused by RSV and in 27% of infections caused by other viruses. In children under six months, RSV were found in 89% by direct antigen detection and in 22% by serology. We suggest that direct antigen detection should be used as the primary virological method in small children with lower respiratory tract infections. The aetiological agents were the same in cases with and without expiratory difficulties, RSV being found in about 40% of children in both instances. It is concluded that host factors are critical to the development of expiratory difficulties.

Scar formation after skeletal muscle injury. A histological and autoradiographical study in rats.

Abstract: The formation of a connective tissue scar was studied autoradiographically 2–42 days following standard contusion injury in the gastrocnemius muscle of 30 rats. The rats were injected intraperitoneally with 3H-labeled proline 4 h before the muscle samples were taken. On day 2 the majority of cells in the injured area were identified as inflammatory without radioactive labeling. Abundant labeling was observed, however, over the extracellular substance, and moderate labeling with 3H-proline in the cells identified as fibroblasts or their precursors. During the first 2 weeks the number of fibroblasts increased and the majority of them were labeled with silver grains, which were also present over the connective tissue matrix. Six weeks after injury only a few fibroblasts showed labeling, and no labeling was observed extracellularly in the connective tissue. Thus, it seems that the synthesis of extracellular connective tissue components in injured skeletal muscle occurs as early as 2 days after trauma, is intensive between days 5 and 21 after trauma, and decreases markedly during the following 3 weeks.

The biochemistry of nitrates, nitrites, nitrosamines and other potential carcinogens in human saliva

Abstract: Human whole saliva protects the oral environment in many different ways from invading pathogenic microorganisms. Human saliva is also capable of inactivating mutagenic and carcinogenic agents by various mechanisms. The peroxidation of these agents is likely to be one of the degrading reactions. However, under certain circumstances some potentially carcinogenic compounds, such as N-nitrosamines, may be generated in whole saliva or -even more likely - in the saliva-gastric juice mixture after swallowing. The formation of N-nitroso compounds requires relatively high intake of nitrate e.g. from vegetable juices. Nitrate is partly reduced to nitrite by oral bacterial enzymes. The nitrosation of various secondary amines is favoured by high salivary (or gastric) concentration of thiocyanate and by low pH. The endogenous generation of N-nitroso compounds may be causally related to the development of oral or gastric cancer.