Biomedical subjects

H Lehtonen

Publications and source records attributed to H Lehtonen.

At least 19 recordsLinked to original sources

PubMed2005

Assessment of environmental impacts following alternative agricultural policy scenarios.

Abstract Finnish agriculture is likely to undergo major changes in the near and intermediate future. The ifuture policy context can be examined at a general level by strategic scenario building. Computer-based modelling in combination with agricultural policy scenarios can in turn create a basis for the assessments of changes in environmental quality following possible changes in Finnish agriculture. The analysis of economic consequences is based on the DREMFIA model, which is applied to study effects of various agricultural policies on land use, animal production, and farmers' income. The model is suitable for an impact analysis covering an extended time span--here up to the year 2015. The changes in land use, obtained with the DREMFIA model assuming rational economic behaviour, form the basis when evaluating environmental impacts of different agricultural policies. The environmental impact assessment is performed using the field scale nutrient transport model ICECREAM. The modelled variables are nitrogen and phosphorus losses in surface runoff and percolation. In this paper the modelling strategy will be presented and highlighted using two case study catchments with varying environmental conditions and land use as an example. In addition, the paper identifies issues arising when connecting policy scenarios with impact modelling.

Agriculture↗

PubMed2001

Tetravalent meningococcal polysaccharide vaccine is immunogenic in adult allogeneic BMT recipients.

Forty-four adult BMT recipients transplanted from an HLA-identical sibling donor were randomized to receive meningococcal polysaccharide (Men PS) vaccine either 8 (early group; 22 patients) or 20 (late group; 22 patients) months after BMT. The geometric mean concentrations (GMC) of antibodies to serogroup A Neisseria meningitidis (Men A) and serogroup C Neisseria meningitidis (Men C), determined by an EIA method, decreased during the first 6 months after BMT but remained at a stable level thereafter. Before vaccination the GMCs of anti-Men A were 1.53 microg/ml and 1.61 microg/ml, but 1 month after vaccination they were significantly higher, 3.46 microg/ml and 6.39 microg/ml, in the early and late groups. The GMCs of anti-Men C increased from 0.37 microg/ml and 0.44 microg/ml before vaccination to 3.31 microg/ml and 4.62 microg/ml at 1 month after vaccination in the early and late groups, respectively. By 6 months after vaccination the GMCs of Men antibodies had decreased to levels of about 50% of those measured at 1 month after vaccination. Two-fold responses to Men A PS were seen in 52% and 74% and to Men C PS in 76% and 89% of the BMT recipients in the early and late groups, respectively. Chronic GVHD had no influence on the vaccination response. In the present study, Men PS vaccine induced good and equal antibody responses to Men A and Men C PSs in allogeneic BMT recipients regardless of timing after BMT. Vaccination against Neisseria meningitidis should be considered, especially in the event of travelling or military service > or = 8 months after BMT.

Adolescent↗

PubMed2001

The effect of esophageal pressure monitoring on nasal airway resistance.

OBJECTIVE: Artificial obstruction of nasal airflow has been shown to increase the amount of apneas and arousals. An esophageal catheter inserted through the nasal cavity is used in sleep studies to show intrathoracic pressure variations as sign of obstructive apneas and increased respiratory resistance. This study evaluates the effect of transnasal esophageal catheter on nasal airflow. STUDY DESIGN AND SETTING: Fifty patients with problem snoring referred to our ENT clinic underwent overnight limited sleep study with an esophageal catheter. Nasal airway resistance was measured the following morning with active anterior rhinomanometry. After exclusion of 17 measurements, the results of 33 patients were compared with same parameters obtained earlier without nasal manipulation. RESULTS AND CONCLUSION: The ipsilateral nasal resistance was clearly elevated when measured with a catheter used overnight compared with the control measurement (P < 0.05). However, the combined nasal resistance was not significantly increased in this material with patent nasal airways. In patients with already compromised nasal airflow, the possibility of clinically relevant changes in nasal airflow during catheter use should be taken in account.

Adult↗

PubMed2001

Free flap reconstructions in the management of oral and pharyngeal cancer.

Fifty patients who had undergone microvascular free flap reconstruction of the oral cavity or pharynx for malignancy between 1989 and 1995 were retrospectively analysed to find factors predicting postoperative complications and outcomes. The mean follow-up time was 2.6 years. More than half (26/50) of the patients had a stage IV malignancy and 10 patients had a recurrent tumour. The overall flap success rate, with 2 flap losses, was 96%. Postoperative medical complications occurred in 29/50 (58%) cases. The recipient site of 10/50 (20%) flaps required re-exploration. Mortality was 2%, with 1 death occurring within 30 days. The mean survival rate after the microvascular operation was 1.6 years, and the 3- and 5-year survival rates were 42% and 23%, respectively. Patients with an oropharyngeal tumour seemed to have the best prognosis and those with a hypopharyngeal tumour the poorest. Men had a threefold greater risk of dying within < 1 year postoperatively compared with women. Tumour stage was the strongest attribute influencing survival. The risk of death after the microvascular procedure increased 2.8-fold when the stage advanced from II to III or from II to IV. None of the tested variables alone could predict complications.

Adolescent↗

PubMed2001

Long-term outcome of anatomical reconstruction versus tenodesis for the treatment of chronic anterolateral instability of the ankle joint: a multicenter study.

The long-term clinical outcome after anatomical reconstruction and tenodesis in the treatment of chronic anterolateral ankle instability was assessed in a retrospective multicentre study. The first group (AR) consisted of 25 patients (mean age at operation 22 yrs +/- 5.7) who underwent anatomical reconstruction and the second group (TE) of 29 patients (mean age 23 yrs +/- 6.6) who underwent tenodesis. For both groups, the mean follow-up period was 12.3 yrs (AR +/- 2.5 yrs, TE +/- 2.7 yrs). At physical examination, there were significantly more patients in the TE group (n=18) with a positive anterior drawer sign as compared with the AR group (n=7) (p=0.02). Medially located degenerative changes in the ankle joint as seen on standard radiographs were seen more often in the TE group (n=7) than in the AR group (n=1) (p=0.03). The mean talar tilt, 4.7 degrees in the AR group vs 6.9 degrees in the TE group, (p=0.02) and anterior talar translation, 2.9 mm in the AR group vs 4.3 mm in the TE group, (p=0.04) were significantly higher in the TE group at radiographic stress examination. According to the rating system developed by Good et al. (1975), significantly fewer patients in the TE group (n=8) had an excellent result as compared with the AR group (n=15) (p=0.03) and more patients in the TE group (n=9) had a fair or poor result (p=0.04) as compared with the AR group (n=2). We conclude that a tenodesis procedure does not restore the normal anatomy of the lateral ankle ligaments. When compared with anatomical reconstruction, a tenodesis leads to inferior results in terms of functional and mechanical stability, as well as overall satisfaction at long-term follow-up.

Adult↗

PubMed2001

Fish stocks in the Baltic Sea: finite or infinite resource?

Human-induced environmental changes, especially eutrophication, and fluctuations of natural environmental conditions under the changes in climate and solar activity affect the reproduction and growth of various fish species and communities in the Baltic Sea. The importance of human impacts has increased considerably during the last decades, overshadowing in many cases natural factors. High exploitation rates have depressed some valuable fish species and affected the species dominance hierarchy. Oxygen depletion in deeper layers progressively deteriorates the living conditions of certain marine species. Mass immigration of nonindigenous species with ballast waters can seriously affect ecosystems and fish stocks. The summary effect of these variables upon marine, relict and freshwater species can yield unexpected results. Fish resources should be properly assessed and managed by their natural units (populations). Based on cyclic fluctuations of global climatic processes, composition of long-term forecasts on changes in the structure and abundance of fish fauna should be started.

Animals↗

PubMed2000

Salivary anti-capsular antibodies in infants and children immunised with Streptococcus pneumoniae capsular polysaccharides conjugated to diphtheria or tetanus toxoid.

Saliva samples of infants and children immunised with pneumococcal vaccines were analysed for anti-polysaccharide (PS) antibodies against the Streptococcus pneumoniae (Pnc) vaccine serotypes 6B, 14, 19F, and 23F. The children received Pnc conjugate vaccine (1, 3, or 10 micrograms of PSs conjugated to diphtheria or tetanus toxoid) or placebo at 2, 4, and 6 months. At 7 months of age salivary PS antibodies were detected rarely. All children received Pnc conjugate or PS vaccine at 14 months of age. At 15 months, both IgA and IgG anti-Pnc PS were found, anti-19F and anti-14 antibodies occurring most frequently and in the highest concentrations. IgA was in the secretory form and predominantly IgA1. A negative dose dependency was observed in IgA anti-19F response. In general, no clear differences in salivary antibody responses were found between the children primed with conjugate vaccine in infancy and those who received their first Pnc vaccine at 14 months of age, suggesting that priming with Pnc conjugate vaccines does not lead to remarkable mucosal memory responses.

Antibodies, Bacterial↗

PubMed2000

Anatomical reconstruction versus tenodesis for the treatment of chronic anterolateral instability of the ankle joint: a 2- to 10-year follow-up, multicenter study.

The clinical outcome of anatomical reconstruction or tenodesis in the treatment of chronic anterolateral ankle instability was assessed in a retrospective multicenter study. The anatomical reconstruction group (group A) consisted of 106 patients (mean age at operation 24 +/- 8.4 years) and the tenodesis group (group B) of 110 patients (mean age at operation 26 +/- 11.4 years). Patients were evaluated at a mean follow-up of 5.5 +/- 2.8 years in group A and 5.2 +/- 2.9 years in group B. The review protocol included patient characteristics, physical examination, two ankle scoring scales to evaluate the functional results, and standard anteroposterior and lateral radiographs to evaluate degenerative changes. Mechanical stability was evaluated using standardized stress radiographs. A larger number of reoperations was performed in group B (P = 0.008). At physical examination, more patients in group B had a smaller range of ankle motion than those in group A (P = 0.009). A larger proportion of patients in group B had medially located osteophytes, as seen on standard radiographs (P = 0.04). On stress radiographic examination, the mean talar tilt (P = 0.001) and mean anterior talar translation (P < 0.001) were seen to be significantly greater in group B than in group A. There were no differences in mean Karlsson score between the groups, but more patients in group A had an excellent result on the Good score (P = 0.011). Unlike anatomical reconstructions, tenodeses do not restore the normal anatomy of the lateral ankle ligaments. This results in restricted range of ankle motion, reduced long-term stability, an increased risk of medially located degenerative changes, a larger number of reoperations, and less satisfactory overall results.

Adolescent↗

PubMed1999

Long-term functional outcome after surgery of chronic ankle instability. A 5-year follow-up study of the modified Evans procedure.

Chronic ankle instability is a rather common consequence of poorly healed rupture of the lateral ligaments of the ankle. In some rare cases, instability symptoms can be caused by general laxity of the joints, but since these cases are normally bilateral, they can easily be distinguished from posttraumatic instability. This report presents the long-term (average follow-up 4.6 years) functional outcome after a modified Evans tenodesis of 48 patients. The follow-up examination consisted of a questionnaire evaluating the subjective assessment of the ankle, and clinical examination measuring ankle stability, range of motion and swelling, and atrophy of the calf muscles. Additionally, the functional recovery of the ankle was assessed by a standardized performance test protocol. According to the subjective assessment, 25 subjects (52%) considered the ankle fully recovered, or at least much better than before surgery. In the performance test, however, only 17 subjects (35%) achieved an excellent or good score. In the performance test protocol, two functional tests, walking down a staircase and balancing on a square beam, best demonstrated the impaired function of the injured ankle. The modified Evans procedure could restore the stability of the ankle to the preinjury level, although the ankle range of motion was significantly impaired, and swelling of the ankle and atrophy of the calf muscles were frequent findings at the follow-up. In conclusion, surgical treatment of chronic ankle instability by the Evans procedure restores the mechanical stability of the joint, but too frequently the function of the ankle does not return to the pre-injury level.

Adolescent↗

PubMed1998

Repopulation during radical radiotherapy for T1 glottic cancer.

BACKGROUND AND PURPOSE: Because opinions on the significance of repopulation during radiotherapy of T1 laryngeal cancer vary, we have estimated the effective rate of tumour cell repopulation during radiotherapy in patients with T1 laryngeal cancer. MATERIALS AND METHODS: One hundred seventeen consecutive patients with T1 laryngeal cancer were treated from 1982 to 1993 by radical radiotherapy alone either as continuous (n = 28) or split-course treatment (n = 89). The logit method of the linear-quadratic formula for local control at 3 years was used to examine the effect of treatment time on local control. The analysis was made for all patients to obtain a wide range of overall treatment times. RESULTS: The 3-year overall survival rate was 76% and the 3-year local control rate was 85% (range 82-88%). The local control rates were 95% (range 94-96%) for the continuous and 81% (range 75-91%) for the split-course therapy groups, respectively. The results showed a mean Dprolif value at the steepest part of the response versus time curve of 0.48 Gy/day for local control at 3 years although this was not statistically significant. The trade-off of dose required to compensate for a 1 week increase in treatment time for local control at the 90% level achieved at 3 years was calculated to be 3.5 Gy. CONCLUSIONS: The present results suggest that repopulation should be taken into account even when treating small T1 laryngeal cancer and that protraction of the overall treatment time should be avoided.

Adult↗

PubMed1998

Streptococcus pneumoniae capsular polysaccharide-diphtheria toxoid conjugate vaccine is immunogenic in early infancy and able to induce immunologic memory.

BACKGROUND: Pneumococcal polysaccharide vaccines are not protective against the most common pneumococcal infections in infancy. The importance of pneumococcal diseases and emerging antimicrobial resistance emphasize the need for prophylaxis. METHODS: Pneumococcal conjugate vaccine, containing capsular polysaccharides from serotypes 6B, 14, 19F and 23F conjugated to diphtheria toxoid (PncD), was given to 75 infants at 2, 4 and 6 months of age. Three dosages (1, 3 or 10 microg of each) were used. A placebo group of 49 infants received physiologic saline. Children were given a booster dose of either polysaccharide or conjugate vaccine at 14 months of age; the placebo group received conjugate vaccine. Antibody concentrations were determined with an enzyme immunoassay. RESULTS: The highest dose induced the strongest response after primary immunization, but booster response was greatest in the group primed with the lowest dose. Polysaccharide and conjugate vaccines induced booster responses of the same magnitude. At 24 and 36 months of age the antibody concentrations were similar in children who had received the PncD in infancy and in children immunized at 14 months of age only. CONCLUSIONS: The PncD conjugate vaccine is immunogenic and able to induce immunologic memory.

Antibodies, Bacterial↗

PubMed1997

Biweekly dose escalation in curative accelerated hyperfractionation for advanced head and neck cancer: a feasibility study.

PURPOSE: To study the feasibility of a dose-escalated accelerated hyperfractionation schedule for patients with advanced head and neck cancer. MATERIALS AND METHODS: Twenty-nine previously untreated patients with advanced squamous cell carcinoma were treated with the following biweekly dose-escalated accelerated hyperfraction schedule: during the first 2 weeks 1.2 Gy twice a daily (bid) up to 24 Gy, thereafter during the next following 2 weeks 1.4 Gy bid to 28 Gy in 20 fractions, and thereafter 22.4 Gy in 1.6 Gy bid fractions during 1 1/2 weeks. Thus, the the total dose was 74.4 Gy in 54 fractions given in 5 1/2 weeks. RESULTS: The planned total dose was given within the planned time to 19 (66%) patients. For seven patients the treatment time was prolonged with 1 to 6 days because of department closure for holidays or machine-down days, and in three cases the treatment time was prolonged more than 8 weeks. When the tumor responses were evaluated at 3 months after given radiotherapy, 27 (93%) patients showed complete tumor clearance, 1 patient had a recidual focus, and 1 patient showed progressive disease. The ultimate 1-, 2-, and 3-year local control rates were: 87, 71, and 60%. Four patients had a salvage laryngectomy. The 1-, 2-, and 3-year survival rates for all patients were as follows: 96, 81, and 73%. All patients developed confluent mucositis, 15 patients were hospitalized for nutritional support, and 11 patients had moist desquamation. However, all acute reactions healed completely, and no serious late complications were observed. CONCLUSIONS: This is a safe and effective treatment schedule for patients with advanced head and neck cancer.

Adult↗

PubMed1997

Assessment of proliferative activity using the MIB1 antibody help to distinguish polymorphous low grade adenocarcinoma from adenoid cystic carcinoma of salivary glands.

Salivary polymorphous low grade adenocarcinoma (PLGA) and adenoid cystic carcinoma (AdCC) bear a superficial histological and immunophenotypic resemblance to each other, but can usually be separated by conventional microscopic examination. However, this is not always so, such as with PLGAs displaying plentiful cribriform structures, and when only limited tissue from small biopsies is available for study. Twenty-one cases of PLGA and 20 cases of AdCC from the surgical pathology files in Plzen, Exeter and Helsinki were incubated with the MIB1 antibody using the supersensitive avidin-biotin peroxidase technique after microwave pretreatment. The antibody recognizes the cell cycle associated antigen Ki-67 on routinely processed formalin-fixed paraffin-embedded tissues. The percentage of positively stained tumor cell nuclei constituted the MIB1 index. It was found that the PLGAs had a mean MIB1 index of 2.4% (range 0.2-6.4), while the AdCCs had a mean value of 21.4% (range 11.3-56.7). Within the PLGA group, the 12 tumors which did not form micropapillae had a somewhat lower mean MIB1 index (1.4%) than those nine in which such structures constituted a significant but minor component (3.4%). These results indicate that the MIB1 index was significantly higher in the AdCCs than the PLGAs and that the figures showed no overlap zone. We conclude, therefore, that immunohistochemical staining with the MIB1 antibody appears to be a potentially useful supplementary diagnostic tool in differentiating difficult cases of PLGA from AdCC.

Adenocarcinoma↗

PubMed1997

The effect of nasal obstruction on outcomes of uvulopalatopharyngoplasty.

Nasal obstruction is considered an aggravating factor in some patients with obstructive sleep disorders. There are no previous reports about the effect of nasal obstruction on outcomes of uvulopalatopharyngoplasty (UPPP). The symptoms of 100 patients treated by UPPP in our hospital were analysed. Forty-nine of them were diagnosed as having obstructive sleep apnea syndrome (OSAS), as ODI 4 was > 5. Nasal obstruction was measured using preoperative anterior active rhinomanometry. The degree of snoring and daytime sleepiness was evaluated using a questionnaire preoperatively and again 6-12 months after the operation. Snoring was relieved in 96% of all patients. Excessive daytime sleepiness improved in 87%, which is also consistent with earlier good results. There was no significant difference in improvement of these symptoms in nonapneic snorers and in patients with OSAS. In the group of 10 patients with highest nasal airway resistance snoring was relieved in only 78% as compared with 98% in the others (p < 0.05). Also excessive daytime sleepiness was better relieved in the group of patent nasal airway, but this difference was not statistically significant. Nasal obstruction can effect the outcome of UPPP. Treatment of nasal obstruction should be considered in chronic snoring if snoring and excessive daytime sleepiness persist after UPPP.

Airway Resistance↗

PubMed1997

Microvascular free flaps in head and neck cancer surgery in Finland 1986-1995.

Microvascular free tissue transfer has in many cases replaced classic flap techniques and is now an established workhorse for head and neck reconstructions. In this retrospective study the over 300 patients, who had microvascular free flap reconstructions in head and neck cancer surgery in Finland during a 10-year period (1986-1995) were reviewed. The operations were performed in the University Hospitals by plastic surgeons, ENT specialists or maxillofacial surgeons. The cases consisted of defects resulting from resection of oral cavity tumors (63%), mid- or upper-face and skullbase tumors (20%) and hypopharyngo-esophageal tumors (17%). The series includes a wide range of flap types and analyses flap outcome and complications. A total of 313 cases was reconstructed by 317 flaps (forearm flaps 47%, latissimus dorsi flaps 19%, free jejunum or colon transfers 15%, free iliaca crest flaps 8% and other flaps 11%). Thrombosis of one of the vessels and haematoma were the most frequent causes of failure in microvascular free tissue transfer. A total flap necrosis occurred in 27 (8.5%) and a partial necrosis in 12 (4%) patients. The most reliable flap in terms of survival was the radial forearm flap. The ever-improving success of microvascular free tissue transfer has made it a useful procedure for head and neck reconstructions. There is also a growing need for microvascular team surgery in the field of head and neck cancer therapy.

Female↗

PubMed1996

Increased acetaldehyde production by mouthwashings from patients with oral cavity, laryngeal, or pharyngeal cancer.

Excessive ethanol consumption is associated with an increased risk of oral cavity, laryngeal, and pharyngeal cancer. Ethanol has been shown to be oxidized to acetaldehyde by microflora of the upper respiratory tract. As a highly toxic and reactive compound, acetaldehyde of microbial origin has been incriminated as a possible carcinogenic factor behind alcohol-associated malignancies of the upper respiratory tract. The aim of the present in vitro study was to compare the acetaldehyde producing capacity of mouthwashings obtained from patients with oral cavity, laryngeal, or pharyngeal cancer to that of mouthwashings from controls. The ability of mouthwashings to produce acetaldehyde from ethanol in vitro was determined by incubating them in closed vials containing various concentrations of ethanol (0-44 mM) at 37 degrees C for 1 hr. Acetaldehyde formed during the incubation was then analyzed by head space gas chromatography. Acetaldehyde production by mouthwashings increased with raising ethanol concentration in both groups. Acetaldehyde production by mouthwashings from patients with oral cavity, laryngeal, or pharyngeal cancer was significantly (p < 0.01) higher than that of the controls. Increased acetaldehyde formation from ethanol in the upper respiratory tract could thus contribute to the pathogenesis of alcohol-associated oral cavity, laryngeal, and pharyngeal cancers.

Acetaldehyde↗

PubMed1996

Nasal-CPAP, surgery, and conservative management for treatment of obstructive sleep apnea syndrome. A randomized study.

STUDY OBJECTIVE: To assess separately the effectiveness and safety of nasal-continuous positive airway pressure (N-CPAP) and that of surgery in comparison to conservative management in patients with obstructive sleep apnea syndrome (OSAS). DESIGN. A randomized study with 1-year follow-up. SETTING: A university hospital acting as a referral center for OSAS. PATIENTS: Symptomatic patients with OSAS (72 male and 4 female patients aged 18 to 65 years), who had oxygen desaturations in the overnight recording. INTERVENTIONS: After the initial diagnostic workup, patients were considered to be candidates for either N-CPAP (44 patients) or surgical treatment (uvulopalatopharyngoplasty [UPPP] with or without mandibular osteotomy) (32 patients). Within the groups, the patients were then randomized to either the assigned treatment or conservative management. MAIN OUTCOME MEASURES: The number of nocturnal oxygen desaturation events of 4% or more per hour in bed (ODI4); daytime somnolence; side effects. RESULTS: N-CPAP Group: Compliance with N-CPAP therapy at 1 year was 13 of 21. The most common reason for noncompliance was general intolerance of CPAP. All compliant patients had a normal ODI4 ( < 10), whereas 1 of 20 of their control subjects had a normal finding. Patients receiving active treatment were significantly less somnolent than their control subjects at 1 year (p < 0.05). SURGERY GROUP: At 1 year, 7 of 18 of the surgically treated and 1 of 14 of the conservatively treated patients had a normal ODI4 (p < 0.001). Daytime somnolence was significantly less severe in the surgically treated patients compared with their control subjects (p < 0.001) both at 3 and 12 months. The overall postoperative complication rate was 22%. CONCLUSIONS: N-CPAP is an effective therapy for OSAS, but compliance is a problem. Surgical therapy (UPPP with or without mandibular osteotomy) needs further evaluation.

Adolescent↗

PubMed1994

Prognostic significance of cell proliferation in mucoepidermoid carcinomas of the salivary gland: clinicopathological study using MIB 1 antibody in paraffin sections.

Mucoepidermoid carcinomas of salivary gland origin have an uncertain clinical course not directly predictable by histomorphology. The MIB 1 antibody, which detects Ki-67 antigen in formalin-fixed, paraffin-embedded tissues, was used to study cell proliferation in these tumors. An MIB 1 index was developed to express the percentage of MIB 1-positive proliferating cells, and the results were compared with histomorphological tumor grade and clinical outcome. All patients with MIB 1 indices lower than 10% in their primary tumors had a favorable clinical outcome. Most patients with MIB 1 indices higher than 10% developed a recurrent or metastasizing disease. All patients who died of their tumor or who had persistent tumor had MIB 1 indices higher than 10%. Thus, the MIB 1 index defines two virtually nonoverlapping forms of the disease, an indolent one and an aggressive one. Cell proliferation in mucoepidermoid carcinomas, assessed with the MIB 1 antibody, thus represents a significant prognostic factor for improving the accuracy of conventional histological grading.

Adult↗