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Biomedical subjects

R Lahti

Publications and source records attributed to R Lahti.

At least 73 records · Page 4Linked to original sources
PubMed1984

Diagnosis of emphysema on chest radiographs.

To evaluate how well pulmonary emphysema could be diagnosed on routine chest radiographs by using generally known criteria, a radio-pathologic correlative study was performed in 88 unselected patients with post-mortem verification of emphysema. The signs used were: I. Signs of overinflation as (a) blunting of the costophrenic sinuses and/or depression of the dome of the right diaphragm, (b) widening of the retrosternal airspace and (c) a right or obtuse sternodiaphragmatic angle, II. Irregular radiolucencies. III. Arterial deficiency. If two or more of the above signs were present, a total accuracy of 77% in detecting emphysema was achieved. The irregular radiolucency and arterial deficiency signs were sensitive but less accurate than those of overinflation.

Adult↗
PubMed1984

Postmortem radiographic, histological and bacteriological studies of terminal respiratory infections and other pulmonary lesions in hospital and non-hospital necropsies.

One lung from 109 unselected hospital and 43 unselected non-hospital necropsies was studied using postmortem radiography with histological verification. Signs of acute bacterial infection, including bronchiolitis or bronchopneumonia, were present in 42.2% of the hospital necropsies and infection was the immediate cause of death in 8.3%. There was only one case of incipient bronchopneumonia among the non-hospital necropsies. Emphysema was the most common other pulmonary lesion in both groups. Gram negative bacteria were found significantly more often in the bronchial mucus of lungs with any pulmonary lesion, particularly those with signs of bacterial infection, than in the bronchial mucus of morphologically normal lungs in both groups of patients. In addition, the frequency of infections was associated with length of stay in hospital. This may reflect the prevalence of Gram negative infections in hospitals.

Adolescent↗
PubMed1983

Post-operative roentgenological findings and changes after mastoid obliteration.

This study consisted of the evaluation of the plain X-ray findings of films taken at early follow-up (mean 1.5 months after surgery) and at late follow-up (4-14 years after the early films) of 211 ears which had been operated on radically and obliterated. Residual cells which were detected on the basis of the early films were associated with a more frequent occurrence of post-operative infection and were thus hallmarks of a poorer prognosis. Changes in the bone surrounding the surgical cavity and the radiological quality of the walls of the surgical cavity, the presence of new bone formation in the cavity and other radiological features did not yield useful information about post-operative complications. New bone formation was associated with a smaller amount of post-operative cavitation. Post-operative X-ray examination of the obliterated ear is a prognostically useful examination, but it does not significantly contribute further to the information available by clinical and otomicroscopic examination in regards to the complications of infection and cholesteatoma.

Adult↗
PubMed1983

A new sensitive, thiol tolerant method for the determination of inorganic pyrophosphatase.

In this work a new sensitive, thiol tolerant method for the determination of inorganic pyrophosphatase (EC 3.6.1.1) was developed. It is based on the formation of phosphomolybdate-triethylamine complex, which in acid-acetone mixture forms a white, homogeneous precipitate, the turbidity of which can accurately measured spectrophotometrically at 355 nm. This method can be easily applied to all the Pi-producing enzymes whose substrates are stable enough in our acidic experimental conditions.

Drug Stability↗
PubMed1983

Pulmonary fibrosis, with sarcoid granulomas and angiitis, associated with handling of mouldy lichen.

We report a case of extrinsic allergic bronchiolo-alveolitis associated with handling of mouldy lichen. The patient had periodic dyspnoea, cough and mucoid sputum, and a micronodular infiltration of both lungs with slight restrictive ventilatory insufficiency. An open lung biopsy showed interstitial inflammation and fibrosis with sarcoid granulomas and angiitis. The symptoms disappeared during long term corticosteroid therapy, but reappeared every year when the patient participated in the handling of lichen (Cladonia alpestris). Precipitating antibodies against Aspergillus fumigatus, A. umbrosus, and Thermoactinomyces vulgaris, were detected in the patient's serum, and against a mixture of fungi including A. terreus, Rhizopus spp., Cladosporium spp., and Penicillium spp., isolated from mouldy lichen storage boxes. After she retired, her symptoms disappeared and the lung function tests showed a slight improvement. In Northern Finland, farmers generally participate in lichen collection. Antigens from mouldy hay and from mouldy lichen may represent a double occupational hazard for them.

Adult↗
PubMed1982

Nonspecificity of some commonly used inhibitors of DNA synthesis in cultures of Streptococcus faecalis.

The specificity of three commonly used inhibitors of DNA synthesis were tested in the batch culture of Streptococcus faecalis ATCC 8043 in rich broth medium. It was shown that nalidixic acid, mitomycin C and 6-(4-hydroxyphenylazo)uracil inhibit the growth of the cell mass as much as they decrease net DNA synthesis. Hence the drugs tested are highly unspecific inhibitors of DNA synthesis in S. faecalis; i.e. they all interfere with other processes as well as with DNA synthesis.

DNA Polymerase III↗
PubMed1982

Role of glutathione in the regulation of inorganic pyrophosphatase activity in Streptococcus faecalis.

When the thiol-oxidizing agent diamide was added to a batch culture of Streptococcus faecalis during exponential growth, the specific activity of inorganic pyrophosphatase (EC 3.6.1.1) decreased to the level observed in the stationary phase. The effect of diamide was completely reversed by reduced glutathione. Furthermore, the ratio of reduced to oxidized glutathione and the specific activity of inorganic pyrophosphatase changed in a very similar fashion during batch culture. These findings, together with our earlier results, suggest that the activity of inorganic pyrophosphatase in S. faecalis is regulated by glutathione via the ratio of reduced to oxidized glutathione.

Cysteine↗
PubMed1982

Accuracy of postmortem radiography of excised air-inflated human lungs in assessment of pulmonary emphysema.

The accuracy of radiography of excised air-inflated lungs in assessing pulmonary emphysema at necropsy was evaluated in a series of 107 adults who had died in hospital by reading the radiographs and examining the pathological specimens independently. The radiographic and pathological assessments of the severity of emphysema correlated significantly (r = 0.87, p less than 0.0001). Mild emphysema was recognised radiographically in 88.7% and moderate in 94.9% of the lungs. One of 16 normal lungs (6.3%) was radiographically diagnosed as showing mild emphysema. Six out of 53 lungs (11.3%) with mild emphysema were radiographically assessed as normal. The correct radiographic recognition of the type of emphysema was possible in 86% of lungs with mild and 97.4% with moderate centrilobular emphysema and in 81.8% and 87.5% respectively of the lungs with mild and moderate paracicatricial emphysema, but in only 25.0% and 28.6% of the lungs with mild and moderate panlobular emphysema. Radiographical diagnosis of centrilobular and paracicatricial emphysema was verified pathologically in all lungs showing mild emphysema, but that of panlobular emphysema in only 66.7%. Radiography of excised air-inflated lungs is a rapid, convenient, and reliable method of recognising and assessing the severity of appreciable degrees of centrilobular and paracicatricial emphysema, but less reliable in recognising panlobular emphysema. After the procedure the specimen remains available for almost any other technique.

Adult↗
PubMed1982

Frequency of rheumatic diseases in patients with acute anterior uveitis.

The frequency of associated rheumatic diseases was studied in 271 patients with acute anterior uveitis (AAU). In a retrospective examination of 154 patients with AUU (mean follow-up period of 6 years) associated rheumatic symptoms were observed in 64 (41.6%). Forty-one patients (26.6%) had ankylosing spondylitis and 39 (25.3%) manifestations of Reiter's disease. Radiographic sacro-iliitis was seen in 35 (34%) of 103 consecutive x-ray examined patients with AAU. Furthermore, in another series of 38 patients, who all, in addition to having AAU, also complained of low back pain or had manifestations of Reiter's disease, 23 (60.5%) had radiographic sacro-iliitis. Classical ankylosing spondylitis was more frequent in men with AAU whereas milder forms of the disease occurred more equally in both sexes. HLA-B27 occurred in 35 (87.5%) of 40 HLA-typed patients with AAU. Associated rheumatic diseases occurred in 18 (51.4%) of the 35 HLA-B27 positive patients but in none of the HLA-B27 negative patients. The results support the hypothesis that a pleiotropic HLA-B27 associated gene may determine the susceptibility to AAU, sacro-iliitis, ankylosing spondylitis, and Reiter's disease.

Acute Disease↗
PubMed1981

Purification and some properties of inorganic pyrophosphatase from Streptococcus faecalis.

Inorganic pyrophosphatase [EC 3.6.1.1] from Streptococcus faecalis ATCC 8043 was purified to homogeneity as judged by slab gel electrophoresis in the presence and absence of sodium dodecyl sulfate. The purification consisted of the following steps: streptomycin sulfate precipitation, (NH4)2SO4 treatment in a Sepharose CL-4B column, DEAE-Sepharose CL-6B chromatography, gel filtration on Ultrogel AcA 34, and preparative slab gel electrophoresis. Gel filtration on Ultrogel AcA 34 was used to determine the molecular weight and slab gel electrophoresis in the presence of sodium dodecyl sulfate to study the subunit molecular weight. The enzyme appeared to be composed of four subunits with molecular weights of approximately 32,500. The molecular weight of the native enzyme was about 128,000. The enzyme catalyzed the hydrolysis of inorganic pyrophosphate, and no activity was found with a variety of other phosphate esters. The cation Mg2+ was required for maximum activity; Co2+ and Ca2+ supported 24% and 5.6% of the activity observed with Mg2+, respectively. 2,4,6-Trinitrobenzene sulfonic acid inhibited the reductants containing SH-groups activated the enzyme suggesting that lysine and cysteine have essential roles in the enzyme.

Cations, Divalent↗
PubMed1981

Activity changes of inorganic pyrophosphatase of Streptococcus faecalis during batch culture.

The state of inorganic pyrophosphatase (EC 3.6.1.1) from Streptococcus faecalis ATCC 8043 was studied in different phases of batch culture. The degree of inactivation (i.e. the ratio of activities observed before and after incubation at 37 degrees C without cysteine) was highest, and the degree of activation (i.e. the ratio of activities after and before incubation in the presence of cysteine) was lowest, in samples taken during the early-exponential growth phase. During the various phases of batch culture, the specific activity before incubation and the degree of inactivation changed in parallel, whereas the specific activity observed after incubation remained nearly constant. During the early-exponential phase of growth almost all the enzyme was in the high-activity form, whereas during the stationary phase the highly active and the less active forms existed in equal amounts. These findings suggest that inorganic pyrophosphatase in S. faecalis is synthesized constitutively and is primarily regulated at the level of activity.

Culture Media↗
PubMed1981

Reversible changes in the activity of inorganic pyrophosphatase of Streptococcus faecalis. The effect of compounds containing SH-groups.

The activity of inorganic pyrophosphatase (EC 3.6.1.1) from Streptococcus faecalis ATCC 8043 decreased rapidly, when the cell extracts prepared by lysozyme and osmotic shock were incubated in a buffer solution (pH 8.0) at 25-50 degrees C. Increase in pH (from 8.5 to 10.5) retarded the inactivation considerably. The low activity level was reached in 2.5 h at 37 degrees C (pH 8.0) and this residual activity was stable during prolonged incubation. The enzyme in the form of low activity was not rapidly denatured until at 70 degrees C. The inactivation could be prevented and reversed by cysteine, dithiotreitol and 2-mercaptoethanol, but reductants, which do not contain SH-groups were not effective. Reduced glutathione slowed down and oxidized glutathione stimulated the inactivation. With pure enzyme it was shown that the low, stable activity level obtained with crude extracts during incubation is a property of inorganic pyrophosphatase and not due to another enzyme with a low capacity to hydrolyze inorganic pyrophosphate. These findings suggest that inorganic pyrophosphatase form S. faecalis exists in two interconvertible forms which differ in activity.

Bacteriological Techniques↗
PubMed1981

Pattern recognition in radiographs of excised air-inflated human lungs. I. Circulatory disorders in non-emphysematous lungs.

To evaluate the patterns of normal lung tissue, alveolar and interstitial oedema, macrophage collections, haemorrhage and infarction in radiographs of excised air-inflated lungs at autopsy, the distribution of these findings in 89 lungs was determined histologically on 441 sections sampled from 59 lungs selected to represent unequivocally the features in question. Normal lung tissue appeared as branching blood vessels with a delicate net-like background. Alveolar oedema gave a fine punctate opacity distributed evenly, and interstitial oedema showed as either short lines perpendicular to the pleural surface, as a network of branching narrow lines, or as long non-branching lines. Macrophage collections associated with chronic congestion showed as a coarsely punctate opacity, but this was often inconspicuous or similar to the pattern of slight alveolar oedema or slight haemorrhage. Massive haemorrhage appeared as a finely macular opacity. Fresh infarction gave a dense wedge-shaped opacity with pleural retraction and a rounded top. An older infarction was less homogeneous with more indistinct borders. The demonstration of thromboemboli without infarction was not possible.

Adult↗
PubMed1981

Pattern recognition in radiographs of excised air-inflated human lungs. II. Acute inflammation in non-emphysematous lungs.

To evaluate the patterns of bronchiolitis, alveolar pneumonia, usual interstitial pneumonia, and local interstitial inflammation in radiographs of excised air-inflated lungs at autopsy the distribution of these findings in 89 lungs was determined histologically on 441 sections sampled systematically. Pathologic-radiologic correlations were then studied on the basis of 33 sections from 24 lungs selected to represent unequivocally the features in question. Discrete alveolar pneumonic infiltrates measuring 2 mm or more in diameter appeared as coarse unhomogeneous macular opacities exhibiting indistinct borders and often following bronchi or bronchioli. Smaller infiltrates or pure bronchiolitis were not distinguishable radiographically. Infiltrates measuring more than 1 cm in diameter appeared confluent with a dense homogeneous centre and indistinct borders. In the midst of the opacities air-bronchograms were often and abscess cavities sometimes visible. Fulminant acute interstitial pneumonia of the usual type showed centrally a dense opacity with air-bronchograms and peripherally trabecular densities distributed non-anatomically. Between the trabecular densities there were uneven punctate opacities and expansion by air-inflation was incomplete. Local interstitial inflammation that caused thickening of the alveolar walls up to 4 time of normal was not distinguishable radiographically.

Adult↗
PubMed1981

Importance of thermoregulation in traumatic and haemorrhagic shock in the anaesthetized rabbit.

The effects of external thermal support was studied in 66 anaesthesized adult rabbits divided into six groups: control, traumatic shock and haemorrhagic shock; each of these groups had a subgroup with an external thermal support and a subgroup without support. During the four hour experimental period, anaesthesia alone resulted in a reduced core temperature and metabolic acidosis. The external thermal support attenuated these changes. In the shocked animals, the external thermal support reduced the mortality, assisted the body's thermoregulation and reduced the adverse metabolic effects of shock.

Acid-Base Equilibrium↗