Jari Peltonen

Distraction osteogenesis of the mandible: An experimental study on sheep

Distraction bone healing has been studied in long bones but there are only few experiments reported in relation to the mandible. The histological pattern of the healing process after mandibular distraction is described. After osteotomy the mandibles of 17 growing sheep were lengthened by gradual distraction using an external fixation device. The follow-up varied from 0 to 52 weeks. The results indicate that bone healing in mandibles is principally the same as in long bones. Four phases can be observed during the repair process: 1) formation of collagen aligned in the direction of distraction, 2) bone formation over the collagen template, 3) bone union across the distraction gap, and 4) remodelling of the lengthened segment. Some increased osteoblast activity was also seen in the control side.

The effect of gradual distraction of the mandible on the sheep temporomandibular joint

The effect of gradual distraction of the mandibular ramus on the condylar process of the temporomandibular joint (TMJ) was studied in 17 growing sheep. Gradual lengthening affected both operated and contralateral sides. An enhancement of the endochondral ossification was noticed with marked osteoblastic activity between the cartilaginous layer and the bone formed. The cartilage was thinner and the bone structure more dense than in nonoperated controls, and woven bone predominated. These changes seemed to be partly reversible in the long term.

Grain yield of high- and low-protein wheat cultivars as influenced by timing of nitrogen application during generative development

Abstract Many techniques have been attempted to alter the negative relationship between grain yield and grain nitrogen (N) concentration in wheat. Better understanding of the varietal and yearly variation of these traits requires a detailed knowledge of the physiology of ear development from the pre-anthesis phase onwards and of the requirements for N fertilization by the developing apex. Two cultivars with contrasting grain yield and protein concentration characteristics were studied under greenhouse conditions in order to establish the effects of N on spikelet and floret development and protein synthesis in spring wheat ( Triticum aestivum L.). The development of wheat was divided into pre- and post-anthesis phases. Two N fertilizer treatments were applied: sufficient for normal growth (C) and excess (E) nitrogen application. Development of the inflorescence, grain yield, N uptake, grain N concentration and protein quality of flour were measured. The application of N fertilizer during the pre-anthesis phase affected fertile floret number more than spikelet number. Pre-anthesis N application increased grain yield and tiller initiation. Post-anthesis nitrogen supply resulted in an improved grain N concentration. Grain N was higher in grain formed on tillers. The contribution from the tillers was also important for protein quality. The use of N fertilization for the stabilization of both grain yield and grain N concentration is discussed.

Range of motion and strength after surgery for brachial plexus birth palsy

Background There is little information about the range of motion (ROM) and strength of the affected upper limbs of patients with permanent brachial plexus birth palsy. Patients and methods 107 patients who had brachial plexus surgery in Finland between 1971 and 1998 were investigated in this population-based, cross-sectional, 12-year follow-up study. During the follow-up, 59 patients underwent secondary procedures. ROM and isometric strength of the shoulders, elbows, wrists, and thumbs were measured. Ratios for ROM and strength between the affected and unaffected sides were calculated. Results 61 patients (57%) had no active shoulder external rotation (median 0° (-75–90)). Median active abduction was 90° (1–170). Shoulder external rotation strength of the affected side was diminished (median ratio 28% (0–83)). Active elbow extension deficiency was recorded in 82 patients (median 25° (5–80)). Elbow flexion strength of the affected side was uniformly impaired (median ratio 43% (0–79)). Median active extension of the wrist was 55° (-70–90). The median ratio of grip strength for the affected side vs. the unaffected side was 68% (0–121). Patients with total injury had poorer ROM and strength than those with C5–6 injury. Incongruity of the radiohumeral joint and avulsion were associated with poor strength values. Interpretation ROM and strength of affected upper limbs of patients with surgically treated brachial plexus birth palsy were reduced. Patients with avulsion injuries and/or consequent joint deformities fared worst.

Use of foliar-applied urea to inhibit the development of Septoria nodorum in spring wheat

Abstract This study was carried out to provide more detailed information about the toxicity of foliar-applied urea on the development of the fungus Septoria nodorum Berk. in wheat, and to examine the interaction between urea and infection on the formation of yield components and grain protein properties. Greenhouse and field experiments involved spring wheat cv. Ruso, which is very susceptible to leaf and glume blotch caused by S. nodorum. Urea solution effectively prevents the development of Septoria infection when applied before inoculation. An agar-plate assay indicated that urea solution > 5% strongly inhibits colony growth. Urea seems to be phytotoxic only if leaf tissue is wetted for an extended period with the solution in the greenhouse. This phytotoxicity would explain the observed decrease in number of grains per ear, ear weight, 1000-grain weight, as well as in residue protein and in SDS sedimentation volume. However, no phytotoxicity and negative effects on yield components and protein properties were observed after urea spray under field conditions. Urea application caused a 0.01–0.04 pmol/100 μl increase in abscisic acid concentration in plant tissue.

Effect of Apical-timed Urea Spraying on Yield Components and Quality Properties of Spring Wheat (Triticum aestivum L.) in Greenhouse Experiments

Abstract The effect of foliar urea spraying on yield components and quality properties of four spring wheat varieties was studied at the University of Helsinki, Department of Crop Husbandry, in greenhouse trials during the autumn of 1988 and the winter of 1989. Nitrogen was applied four different developmental stages of the wheat ear. Foliar urea spraying had different effects on the examined wheat genotypes. Only yield components of a new Finnish variety, ‘Heta’, seemed to benefit from nitrogen application. Foliar spraying of urea increased the protein content and the amount of wet gluten in all varieties. The falling number of ‘Heta’ and ‘Kadett’ improved.

Field Chlorophyll Measurements for Evaluation of Timothy Nitrogen Status for Optimized Seed Yield

Abstract Leaf chlorophyll content, determined with a portable chlorophyll meter (Minolta SPAD-502) in the field, was used to predict N availability of timothy (Phleum pratense) for high seed production. Critical chlorophyll meter readings (SPAD values) were calculated from data derived from experiments with various N fertilizer levels using the Cate-Nelson procedure. According to the results of this study it can be stated that the critical SPAD values at the beginning of stem elongation (GS 30) were 35 SPAD units for timothy seed yield. The optimum seed yield occurred at 42 SPAD units. Determination of leaf chlorophyll content using the chlorophyll meter could be an effective diagnostic tool for optimizing seed production of timothy by N fertilization.

Stability of Quality Traits in Spring Cereals Cultivated under the Growing Conditions of Southern Finland

Abstract High-quality cereal grains are annually required for processing in the food and feed industry. Therefore, the present study focuses on the evaluation of the phenotypic stability of some important quality characteristics of barley, oats and spring wheat cultivars on the basis of 41, 38 and 21 field experiments, respectively. Field trials were carried out at the Experimental Farms of Hankkija Plant Breeding Institute (Anttila and Nikkila) over seven successive years (1982–88). The stability of the quality characteristics was examined using the Finlay-Wilkinson regression method and the Eberhart-Russell stability analysis, both widely used in evaluations of yield stability. In the present study genotype × environment (G × E) interaction was insignificant in the protein concentration of barley; 1000 grain weight, hectolitre weight, protein yield and husk content of oats; as well as hectolitre weight, Zeleny sedimentation volume, and falling number of wheat. Therefore, for these particular quality tra...

Tissue Nitrogen as a Base for Recommendations of Additional Nitrogen to Spring Wheat in Southern Finland

Abstract Nitrogen (N) deficiency has become more common in the traditional wheat cultivation areas of southern Finland as yield potentials have increased. Based on data for the period studied (1968-88) a grain protein concentration below 11.2% in spring wheat (Triticun aestivum L.) is an indicator of N deficiency. The mean of maximum grain yield obtained was 4655 kg ha−1 when grain protein concentration exceeded 11.2%. The estimation of plant tissue N content could be an effective diagnostic tool for identifying N status in the early growth stages of spring wheat. To address the feasibility of this test, the present study was conducted in 1990-91 to determine the critical plant tissue N concentrations of three plant parts at the early double-ridge stage (Stage 2), at the stage when stigmatic branches of the carpel begin to form (Stage 7) and at pollination (Stage 10). Nitrogen was applied at rates of 0 and 110 kg N ha−1 as granular ammonium nitrate and granular slow-release-nitrogen fertilizers to establi...

A Dynamic Model for Predicting the Falling Number of Wheat Grains in Scandinavian Climatic Conditions

Abstract A dynamic model based on daily climatological data enabling the prediction of changes in falling number during grain filling has been developed. The feasibility of the dynamic model was tested with three spring wheat varieties in Scandinavian growing conditions. The goodness of fit of the model in describing starch quality as measured by falling number was highly significant for two of the three tested varieties (Atle and Norrona; R 2=0.90). The falling number of the variety Svenno was generally low and the model was unable to predict the small changes in falling number (R 2=0.40) occurring due to fluctuations in daily climatic conditions. However, we are presently developing a more comprehensive model through inclusion of variables such as changes in endogenous growth regulator balances before dormancy, the effect of lodging, and the damage caused by the orange wheat blossom midge.