Biomedical subjects

J Laitinen

Publications and source records attributed to J Laitinen.

At least 19 recordsLinked to original sources

PubMed1995

Cell transformation by c-Ha-rasVal12 oncogene is accompanied by a decrease in histone H1 zero and an increase in nucleosomal repeat length.

The activated c-Ha-rasVal12 oncogene is often involved in the genesis of human malignancies. We show here that in c-Ha-rasVal12 oncogene-transformed mouse NIH 3T3 fibroblasts the copy number and expression level of the mutant ras oncogene correlates with the degree of chromatin decondensation, as assessed by micrococcal nuclease (MNase) and DNase I digestion. MNase and DNase I analyses further revealed that the nucleosomal repeat lengths were different in the normal and ras oncogene-transformed cells, 162.3 bp and 178.1 bp, respectively. These chromatin changes were accompanied by alterations in the content of histone H1 zero. Furthermore, using DNase I as a probe, we discovered that serum stimulation of normal and transformed cells, synchronized by serum starvation, induces rapid reversible changes in the structure of bulk chromatin that may be linked to transcriptional activation. Our data thus indicate that cell transformation by ras is associated with specific changes in chromatin structure that make it more vulnerable, and prone to additional mutations characteristic of cancer development in vivo.

3T3 Cells↗

PubMed1995

DNA methylation is not involved in the structural alterations of ornithine decarboxylase or total chromatin of c-Ha-rasVal 12 oncogene-transformed NIH-3T3 fibroblasts.

The ornithine decarboxylase (odc) gene is an early response gene, whose increased expression and relaxed chromatin structure is closely coupled to neoplastic growth. In various tumour cells, the odc gene displays hypomethylation at the sequences CCGG. Hypomethylation of genes is believed to correlate with chromatin decondensation and gene expression. Since a given pattern of DNA methylation may not be preserved in neoplastic cells, we studied the methylation status of odc gene at the CCGG sequences in c-Ha-rasVal 12 oncogene-transformed NIH-3T3 fibroblasts during the growth cycle and relative to their normal counterparts. We found that the methylation state of the odc gene and its promoter and mid-coding and 3' regions remain unaltered during the cell cycle. We also found that in ras oncogene-transformed cells, which display a more decondensed nucleosomal organization of chromatin than the normal cells, the CCGG sequences in bulk DNA and at the odc gene were methylated to the same extent as in the nontransformed cells. These data suggest that DNA hypomethylation at the CCGG sequences is not a prerequisite for chromatin decondensation and cell transformation by the c-Ha-rasVal 12 oncogene.

3T3 Cells↗

PubMed1995

U2-snRNP B" protein gene is an early growth-inducible gene.

In this work we isolated mouse U2-snRNP-specific b" clones and analysed the expression of the mouse U2-snRNP-specific b" and U1-snRNP-specific 70K genes in NIH-3T3 fibroblasts. Stimulation of growth-arrested NIH-3T3 cells with serum was found to evoke a rapid increase in the amount of cytoplasmic b" and 70K mRNAs. These increases in mRNA did not require de novo protein synthesis. Moreover, the inhibition of protein synthesis by cycloheximide caused a superinduction in the amounts of the U1-snRNP-specific 70K transcripts. We also found that c-Ha-rasVal12 oncogene-transformed NIH-3T3 cells have higher levels of the b" and 70K mRNAs than the normal 3T3 cells. These data imply that the b" and 70K are early growth response genes, and their enhanced expression might be of significance in the processing of pre-mRNAs into mature mRNAs.

3T3 Cells↗

PubMed1995

Exposure to glycols and their renal effects in motor servicing workers.

Ten car mechanics frequently exposed to glycol-based cooling liquids were followed during a workshift. Airborne ethylene and propylene glycol concentrations in the car mechanics' environment were measured. The car mechanics gave urine samples after the workshift and their excretion of ethylene glycol, propylene glycol, oxalic acid, calcium and ammonia was analysed and compared to that of unexposed office workers. Urinary succinate dehydrogenase activity and glycosaminoglycans were also measured in both groups. Airborne ethylene and propylene glycol concentrations in the car mechanics' environment were negligible. Urinary ethylene glycol excretion in exposed workers was significantly higher than that in unexposed workers, but propylene glycol excretion was at the same levels as in controls. In the exposed group, the excretion of the end metabolite of ethylene glycol, oxalic acid (47 +/- 11 mmol/mol creatinine, mean +/- SD, n = 10) differed slightly from that of controls (36 +/- 14 mmol/mol creatinine, mean +/- SD, n = 10). Urinary excretion of ammonia was higher among exposed workers than office workers. The excretion of calcium did not differ from that of controls. A marginally decreased urinary succinate dehydrogenase activity was found in the exposed men. The excretion of glycosaminoglycans was significantly lower in exposed workers. Therefore, it seems that ethylene glycol is absorbed by skin contact. The internal body burden is associated with oxaluria and increased ammoniagenesis typical of chronic acidosis.

Air Pollutants, Occupational↗

PubMed1995

Characterization of interstitial collagenases in jaw cyst wall.

Neutral salt extracts of 14 specimens of jaw cysts were prepared. Histopathological analysis showed that the specimens consisted of 6 radicular cysts, 6 dentigerous cysts, 1 residual cyst, and 1 odontogenic keratocyst. One periapical granuloma, 1 dental follicle and a sample of clinically healthy oral mucosa were similarly processed and used as controls. Measurement of collagenase activity by monitoring the formation of specific degradation products of type I and II collagen in solution by SDS-PAGE demonstrated that all the cyst extracts contained collagenase, some of which was endogenously activated. Cyst wall collagenase preferably degraded type I over type II collagen, which suggests that the degradation was due to MMP-1 (matrix metalloproteinase-1) rather than the MMP-8 type. This was further supported by the doxycycline-inhibition profile of cyst collagenase, which was similar to that of MMP-1. Part of the cyst wall collagenase was in latent proenzyme form and probably derived, at least in part, from the newly synthesized intracellular collagenase pool. Latent cyst collagenase was efficiently activated with phenylmercuric chloride and to a lesser extent by gold (I) thioglucose and NaOCl. Western-blotting, using specific antibodies against collagenase from human polymorphonuclear neutrophilic leukocytes (MMP-8) and from fibroblasts (MMP-1), revealed a typical 55/45 kDa doublet; also MMP-8 in the latent 80 kDa form and fragmented to 65 kDa active species were found. These results suggest the presence of MMP-1 and, to a lesser extent, MMP-8 type collagenase in the cyst wall.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1994

Methylation status and chromatin structure of an early response gene (ornithine decarboxylase) in resting and stimulated NIH-3T3 fibroblasts.

The early response gene ornithine decarboxylase (odc) is indispensable for normal and malignant cell growth. Although DNA methylation is generally associated with chromatin condensation and gene inactivation, the odc gene is heavily methylated at CCGG-sequences in animal cell lines. In this work we analyzed the chromatin structure and the DNA methylation status at the CpG-rich promoter sequences at the odc locus in mouse 3T3 fibroblasts. We show that the proximal promoter region of the odc locus is not hypermethylated, while the distal promoter sequences appear to have a few methylated CCGG-sites and display methylation polymorphism. Furthermore, it was found that the 5' promoter region of odc is constitutively more sensitive to micrococcal nuclease than the coding and 3' regions of the odc gene. Stimulation of the cells with serum resulted in an appearance of a DNase I sensitive site at the promoter region. The chromatin structure of the mid-coding and 3' regions of the odc gene also underwent structural changes that were accompanied by the rapid accumulation of odc mRNA. Such changes were not detected in the chromatin structure of glyceraldehyde-3-phosphate dehydrogenase (gadph) gene, whose expression remains invariant upon serum stimulation. These data suggest that the chromatin structure may play an important role in the rapid transcriptional activation of odc and other immediate early genes during serum stimulation.

3T3 Cells↗

PubMed1994

Urinary biochemistry in occupational exposure to glycol ethers.

Glycol ethers and glycol ether acetates are dehydrogenated to alkoxyacetic acid congeners which may serve as biological indicators of exposure. The ethereal bond may also be cut in an oxidation reaction catalyzed by the mixed function oxidase. In case of ethylene glycol, the eventual endproduct is oxalic acid. Urinary oxalic acid and alkoxyacetic acid excretion together was found to relate to the decrease of the succinate dehydrogenase activity (SDH) as an indicator of renal mitochondrial effects. The excretion of ammonia by exposed workers was doubled as compared to controls. The excretion of chloride was found to be smaller in the exposed than in controls. The excretion of calcium and glycosaminoglycans (GAG) among exposed workers were similar compared to controls.

Air Pollutants, Occupational↗

PubMed1994

The effect of four-day round trip flights over 10 time zones on the circadian variation of salivary melatonin and cortisol in airline flight attendants.

The effects of four-day round flights (Helsinki-Los Angeles-Seattle-Helsinki) were studied on the circadian rhythms of salivary melatonin (MT) and cortisol (COR) in 35 flight attendants. The mean age of the subjects was 33 +/- 7 years (median 34, range 21-50). Five 24 h profiles of unstimulated saliva were collected at 2 h intervals (except at 04:00) before, during, and after the four day flight. Salivary MT and COR were determined by radioimmunoassay. Both MT and COR exhibited a clear circadian rhythm with acrophases before the flight at 03:03 (MT) and 09:08 (COR). Two days after the westward flight from Helsinki to Los Angeles, the MT rhythm (circadian acrophase) had delayed 4 h 51 min and the COR rhythm 3 h 55 min compared to the control day before the flight. Two days later, during the last day in the USA, the MT rhythm had delayed 5 h 59 min and the COR rhythm 5 h 29 min as compared to the situation before the flight. After four days of the eastward flight from Seattle to Helsinki, the circadian acrophase of MT was still 1 h 35 min delayed compared to the control day before the westward flight. The results indicate that the restitution time of five days at the home base is on the average proper for recovery, if a four day round flight over 10 time zones takes four days or less. The resynchronization rate of salivary hormones after westward, outgoing flights is faster than the resynchronization rate after the eastward return flights.

Adult↗

PubMed1994

Information value of magnetic resonance imaging in shunted hydrocephalus.

OBJECTIVE: To study the role of magnetic resonance imaging (MRI) in evaluating children with shunted hydrocephalus. METHODS: Sixty one asymptomatic children with shunted hydrocephalus or cystic cerebrospinal fluid collections were studied by cranial MRI. The information obtained from the images was classified into three categories: provided (1) a new diagnosis, (2) additional information, or (3) no essential new information. The findings were compared with those of the last follow up computed tomograms. RESULTS: MRI provided a new diagnosis in seven cases (11.5%), and additional information was obtained in 34 (55.7%) cases. In 20 cases (32.8%) no essential new information was obtained. MRI visualised white matter lesions and corpus callosum pathology more often than computed tomograms. CONCLUSIONS: MRI provided new important information in cases of children with shunted hydrocephalus to such an extent that it can be recommended as the primary imaging method for every child with this disorder.

Adolescent↗

PubMed1994

Sinus aspirates and radiographic abnormalities in severe attacks of asthma.

We evaluated the occurrence of abnormalities in paranasal sinus radiographs in acute asthma by taking a radiograph of the sinuses of 110 consecutive patients admitted to a medical ward a total of 149 times for asthma. Maxillary sinus infection was assessed by taking aspirate from radiologically abnormal maxillary sinuses. An abnormal finding in any paranasal sinus was detected on 87% (130 of 149) of admissions and the yield of maxillary aspirate was macroscopically mucous, purulent or mucopurulent in 60% (42 of 70) of aspirates. A positive bacteriological culture was obtained from 23 aspirates and a virus was detected in 15, there being 7 aspirates in which both a bacterium and a virus could be detected. Although the correlation between radiographic findings and the aspirates was not very close we conclude that radiographic abnormalities of the paranasal sinuses are common in acute asthma as are infections of maxillary sinuses with an abnormal radiographic finding. There is an obvious need to look for sinusitis when a patient with an exacerbation of asthma is being evaluated.

Acute Disease↗

PubMed1994

Contribution of chest and paranasal sinus radiographs to the management of acute asthma.

In order to evaluate the clinical utility of chest and paranasal sinus radiographs on admission in cases of acute asthma, the radiographs of adult patients admitted to our hospital for acute asthma over a period of 1 year were studied. The findings were specified afterwards by a senior diagnostic radiologist and their impact on the management of asthma was evaluated by reviewing the medical records of the patients retrospectively. Abnormalities were detected in 50% of the chest radiographs (55 of 110) and these resulted in management changes in 5% of cases (6 of 100). Abnormalities in any paranasal sinuses were detected in 85% of the sinus radiographs (93 of 100), and maxillary sinus abnormalities in 63% (70 of 100). 29% of the sinus abnormalities (32 of 110) resulted in an immediate alteration in treatment. Hence abnormalities were more common in the paranasal sinus radiographs than in the chest radiographs (p < 0.001), and the impact of the sinus radiographs on the treatment of asthma was also greater (p < 0.001). We recommend that while obtaining a chest radiograph routinely may be advisable in severe cases of acute asthma, at least when the patient is admitted to hospital, serious thought should be given to routinely obtaining a sinus radiograph in these cases as well.

Acute Disease↗

PubMed1994

Physical activity and fibrinogen concentration in newly diagnosed NIDDM.

OBJECTIVE: To evaluate whether plasma fibrinogen concentration is correlated with the level of physical activity and aerobic power in patients with newly diagnosed non-insulin-dependent diabetes mellitus (NIDDM). RESEARCH DESIGN AND METHODS: We studied 78 middle-aged (54 +/- 6 years, mean +/- SD), obese (body mass index [BMI] 32+/- 5 kg/m2) patients (45 men and 33 women) before and after a 12-month treatment period consisting of either conventional treatment given by community health centers or intensified dietary and exercise education given by a university outpatient clinic. Plasma fibrinogen concentration was measured by using a coagulometer. Physical activity was assessed by a questionnaire, and the patients were classified into a sedentary group or moderately or intensively exercising groups. Aerobic power (maximum oxygen uptake [VO2max], anaerobic threshold [VO2at]) was measured by direct breath-by-breath technique. RESULTS: At baseline, the sedentary patients had higher fibrinogen concentration than those with moderate or high physical activities (3.8 +/- 0.8 vs. 3.3 +/- 0.7 g/l, P < 0.01). Both VO2max and VO2at (ml.min-1.kg-1) showed an inverse linear correlation with fibrinogen (r = -0.38, P < or = 0.001, and r = -0.29, P < 0.01, respectively). In the stepwise multiple regression analysis, BMI, VO2 (ml/min), and smoking were the only significant independent factors explaining 23% of the variance in fibrinogen concentration. In sedentary patients, poor glycemic control was related with high fibrinogen concentration. During the follow-up period, patients maintained, on the average, good to moderate glycemic control. The originally sedentary group showed a decrease in fibrinogen concentration (to 3.3 +/- 0.7 g/l, P < or = 0.001) that reached the same level that the physically more active groups had at baseline. This change was associated with improved glycemic control, but not with any of the other assessed factors, including fatty acid composition of serum lipids reflecting dietary intake of fats. CONCLUSIONS: In addition to BMI and smoking, low reported physical activity and low aerobic power are independently associated with high plasma fibrinogen concentration in newly diagnosed NIDDM.

Adult↗

PubMed1994

Metabolic and dietary determinants of serum lipids in obese patients with recently diagnosed non-insulin-dependent diabetes.

The aim of the study was to ascertain the metabolic and dietary determinants of changes in serum lipids during a 15-month diet therapy of obese patients (n = 71, 41 males, 30 females) with recently diagnosed Type 2 (non-insulin-dependent) diabetes. The subjects lost weight and improvement in glycaemic control was observed, but due to variation in individual responses the mean serum total cholesterol or non-HDL cholesterol did not change significantly. The proportion of palmitic acid decreased and that of linoleic acid increased in serum lipids during the study, and serum triglycerides decreased and HDL-cholesterol increased. In univariate analyses, decreased serum triglyceride level was associated with serum triglycerides at baseline, decreases in body mass index, fasting blood glucose and palmitic acid proportion of serum triglycerides, and the intake of saturated fats and dietary fibre, but in multiple regression analyses the determinants for decreased serum triglycerides were high serum triglycerides at baseline and a decreased proportion of palmitic acid in serum triglycerides. In univariate analysis, increased HDL-cholesterol was associated with the baseline HDL-cholesterol, decrease in the triceps/subscapularis ratio and the intake of saturated and mono-unsaturated fatty acids, but none of these variables had an independent contribution to the increase in serum HDL-cholesterol in multiple regression analysis. In conclusion, a reduction of palmitic acid in the serum lipids, which was probably due to reduction of dietary saturated fatty acids, had beneficial effects on serum lipids in obese patients with Type 2 diabetes, independently of weight loss and improvement in glycaemic control.

Adult↗

PubMed1994

A nontoxic and versatile protein salting-out method for isolation of DNA.

A pivotal technique in basic and applied molecular biology is the isolation of DNA. However, the present DNA extraction methods are either toxic, expensive, time-consuming and laborious or restricted to certain applications. Here we describe a nontoxic and versatile protein salting-out method for convenient and rapid extraction of large as well as small DNA molecules from vertebrate cells and plasmid DNA from bacteria. Easy and relatively imprecise manipulations of a large number of samples result in high yields of pure mammalian and plasmid DNA that are suitable for transformation of bacteria, restriction enzyme analyses, Southern blotting, end labeling of DNA, PCR and sequencing.

Animals↗

PubMed1993

Cervical intervertebral foramen narrowing and myelographic nerve root sleeve deformities.

Intervertebral foramen narrowing on plain radiographs of the cervical spine was graded from 0 (normal) to 3 according to its severity; myelographic nerve root sleeve deformity was graded from 1 to 3 in 99 consecutive patients with cervical radiculopathy. We thus examined 1118 foramina and root sleeves. Plain radiographs of 684 foramina were normal, changes of one grade were seen in 243, of two grades in 145 and of three grades in 46. Grading of myelographic root sleeves' was normal in 789, changes of one grade in 157, of two grades in 129, and of three grades in 43. The correlations between the foraminal and root sleeve changes were: full correlation in 63.9%, a difference of one grade in 27.4%, a difference of two grades in 7.4% and a difference of three grades in 1.3%. The positive predictive value of the plain radiographs for myelographic root sleeve deformities was 55.5% and the negative value 87.1%.

Adult↗

PubMed1993

The maintenance of improved metabolic control after intensified diet therapy in recent type 2 diabetes.

Altogether 86 patients with recently diagnosed NIDDM, aged 40-64 years were randomised after 3 months of basic education to intensified diet (Int. group, 21 men, 19 women) or conventional treatment groups (Conv. group, 28 men, 18 women). The aim was to examine whether an intensified diet education would result in a better metabolic control and greater reduction in cardiovascular risk factors than conventional treatment for obese patients with recently diagnosed type 2 diabetes mellitus. Furthermore, both groups were re-examined after a second year of observation period to find out the maintenance of the results after intervention. After basic education, Int. group participated in 12-months diet education, while Conv. group was treated in local health centres. During the intervention period, only Int. group showed further weight reduction. Only 20% of patients in Int. and 6% of patients in Conv. group had BMI < 27 kg/m2 at the end of the intervention, while 75% of patients in Int. and 52% of patients in Conv. group had achieved a good metabolic control (fasting blood glucose < 6.7 mmol/l; P = 0.005 between groups). Serum total cholesterol did not change significantly, but the changes in HDL-cholesterol, triglycerides and apolipoprotein B level were significant in Int. group only. The proposed acceptable values for serum lipids were achieved by 52 to 88% of patients without major differences between the two groups. During the second year of observation, weight gained in both groups and a deterioration was seen in metabolic control. Despite that a greater proportion of patients in the Int. group still was in good metabolic control (55.3% vs. 31.8%, P = 0.016), furthermore Int. group was receiving less frequently oral drugs for hyperglycaemia than Conv. group. No differences in serum lipids were observed between the groups after the observation period. HDL-cholesterol showed a persistent improvement in both groups.

Adult↗

PubMed1993

Fate of Nissen fundoplication after 20 years. A clinical, endoscopical, and functional analysis.

Of 46 patients who had Nissen fundoplication for proved gastro-oesophageal reflux, 25 were available for follow up after a median of 20 years, 15 had died of unrelated causes, and six could not be traced. All 25 patients in the follow up study were personally interviewed: 21 consented to an endoscopy, 14 to 24 hour recording of oesophageal pH and manometry, and 15 to radionuclide transit test. Repeat fundoplication for recurrent reflux was performed in two cases during the study. Heartburn and regurgitation were significantly lessened (p < 0.005), but the incidence of dysphagia was slightly increased. Endoscopy showed six of 21 fundic wraps to be defective. Erosive oesophagitis was seen in two patients, and Barrett's oesophagus (histologically confirmed) in one of them and six other patients. Total reflux time was abnormal in four of 14 patients. No patient with an intact fundic wrap seen on endoscopy, only two of seven with Barrett's oesophagus, and one of four with abnormal reflux had oesophagitis. Fundoplication in itself did not affect oesophageal motility or transit, provided that the wrap was intact. It is concluded that Nissen fundoplication gave a reasonably good longterm effect in chronic reflux disease, with the stage of the fundic wrap as the main determinant of outcome.

Adult↗

PubMed1993

Psychosocial changes in patients participating in a chronic obstructive pulmonary disease rehabilitation program.

Changes in physical competence, respiratory symptoms, well-being, emotional state, level of depression, every-day coping skills, and general activity and independence were studied in 40 chronic obstructive pulmonary disease patients participating in an intensive 3-week rehabilitation program. Both patient and staff ratings were used. Expectations and attitudes prior to rehabilitation were also measured. The study design included a 3-week basal period, a 3-week rehabilitation period and a 6-month follow-up. The immediate effects of rehabilitation on the variables which described subjective experiences were positive: well-being, emotional state and respiratory symptoms improved significantly (p < 0.001, p < 0.01 and p < 0.01, respectively). By the end of the follow-up period, however, all the treatment effects had dissipated. No significant effects of rehabilitation could be seen in every-day coping skills, general activity and independence or level of depression. It was not possible to predict the rehabilitation response on the basis of the patients' attitudes, expectations, level of depression or age. We conclude that pulmonary rehabilitation causes transient improvement in respiratory symptoms and some subjectively characterized psychosocial variables and that this improvement is unpredictable by attitude and expectation variables.

Adaptation, Psychological↗