Ovipleistophora gen. n., a new genus for Pleistophora mirandellae-like microsporidia.

Based on ultrastructural study and molecular analysis, a new genus, Ovipleistophora, is established for Pleistophora mirandellae-like microsporidia from roach and ruff oocytes. Unlike Pleistophora, Ovipleistophora has a thick additional envelope around the meront. This envelope breaks open to release the cells into the host cell cytoplasm. The cells, becoming multinuclear sporogonic plasmodia, already have a surface coat that transforms into the sporont wall and eventually into the sporophorous vesicle wall. The surface coat and its transformation differ from those of Pleistophora, but bear some resemblance to those of Trachipleistophora. In Trachipleistophora the sporonts, however, do not form plasmodia, as they do in Ovipleistophora and Pleistophora. Small subunit ribosomal DNA analysis supports the establishment of the new genus and assignment of P. mirandellae from 2 different fish hosts to the same species. The same small subunit ribosomal DNA analysis lends support for transferring P. ovariae into the genus Ovipleistophora.

Ultrastructure of the wall of the sporophorous vesicle during sporogony of Pleistophora mirandellae (Protozoa:Microspora).

The wall of the younger sporophorous vesicle (enclosing the sporogogonial plasmodium) of Pleistophora mirandellae Vaney and Conte, 1901 is composed of a membranous labyrinth, about 0.3-0.6 microns high, interwoven with host cell cytoplasm. There is electron-opaque matter within the partitions of the labyrinth. At the onset of plasmotomy, the partitions of the labyrinth become shorter and then possibly due to stretching of the wall and withdrawal of the membranes, the electron-opaque matter is ejected to the lumen side of the wall and the partitions disappear. Only cisterna-like remains of the partitions are observable outside the electron-opaque layer. The thickness of walls in vesicles with ripe spores can be even less than 100 nm.

Comparisons of Gymnophallid digeneans from north Pacific and Baltic clams, Macoma balthica (Bivalvia).

Three gymnophallid species in Macoma balthica from the northeastern Pacific Ocean are similar to 3 species in M. balthica from the Baltic Sea. Using light and scanning electron microscopy, we compared the anatomy of the larvae of 2 species of Lacunovermis and of Gymnophallus, and the adults of 2 species of Lacunovermis recovered from incubation on chick allantoic membrane. The third similar pair of Meiogymnophallus multigemmulus and Parvatrema affinis was restudied with light microscopy. Previously described anatomical differences between the 3 pairs of Pacific and Baltic gymnophallids were nullified in this study. Lacunovermis conspicuus Ching, 1965 is synonymized with Lacunovermis macomae (Lebour, 1908), and Gymnophallus gibberosus Loos-Frank, 1971 is synonymized with Gymnophallus somateriae (Levinsen, 1881). Meiogymnophallus multigemmulus Ching, 1965 is synonymized with Parvatrema affinis (Jameson and Nicoll, 1913), becoming M. affinis n. comb.

Seven-year follow-up of white-finger symptoms and radiographic wrist findings in lumberjacks and referents.

OBJECTIVES: In 1978, a cross-sectional study of 279 lumberjacks exposed to hand-arm vibration and 178 unexposed referents was conducted. The aim of the present study was to provide a seven-year follow-up on (i) the changes in the white-finger symptoms among the lumberjacks and the referents, (ii) the effect of white-finger symptoms on the professional prognosis of the lumberjacks, and (iii) the relationship between hand-arm vibration and changes in wrist bones. METHODS: The methods consisted of a questionnaire, a routine clinical examination, and radiographs of the wrists and hands. The examinations were conducted as a field study using a mobile unit. RESULTS: The prevalence of white-finger symptoms was 18% among the lumberjacks and 3% among the referents in the original study. Seven years later 213 lumberjacks and 140 referents participated in the follow-up. The prevalence of white-finger symptoms was 24.9 among the lumberjacks and 5.7 among the referents, and the seven-year cumulative incidence was 14.7% among the lumberjacks and 2.3% among the referents. After allowance for age, there was no difference in the incidence of white-finger symptoms between the lumberjacks with fewer than 15 years of exposure and the referents, but the risk increased with increasing duration of exposure (risk ratio 8.9, 95% confidence interval 2.5-28.9 for those exposed at least 25 years). There was no difference between the two groups in the prevalence of radiographically detectable translucencies or osteoarthrotic changes in the wrists and hands. CONCLUSION: According to the results, white-finger symptoms are still a problem among lumberjacks who started chain-saw work before 1970.

Magnetic fields of video display terminals and spontaneous abortion.

The aim of this study was to examine whether work with a video display terminal and exposure to the magnetic fields of video display terminals are related to spontaneous abortion. The study was conducted among women employed as bank clerks and clerical workers in three companies in Finland. The cases (191 spontaneous abortions) and controls (394 births) were identified from Finnish medical registers for the years 1975-1985. Use of video display terminals was defined using the workers' own reports and information provided by the companies. The assessment of exposure to the magnetic fields was based on measurements of the fields of video display terminals. The odds ratio for spontaneous abortion for working with video display terminals was not increased (odds ratio = 1.1, 95% confidence interval 0.7-1.6). However, the odds ratio for workers who had used a video display terminal with a high level of extremely low frequency magnetic fields (> 0.9 microT) was 3.4 (95% confidence interval 1.4-8.6) compared with workers using a terminal with a low level of these magnetic fields (< 0.4 microT). Adjustment for ergonomic factors and mental work load factors changed the odds ratio for magnetic field exposure only very slightly. The findings suggest the need for future studies with assessment of exposure to the magnetic fields in the actual working environment to confirm the possible risk.

Diet and physical activity of men in east and west Finland in 1969.

The purpose of the study was to discover the effects of physical activity on men's diets. The food consumption of 1306 men aged 50 to 69 years was studied using the dietary history method. The men were grouped in four classes according to their physical activity. With increasing activity their consumptions of cereals, potatoes, milk and milk products, fats and sugar increased. The men in East Finland used more milk, butter and fish than those in the West. The consumption of cereals, potatoes and eggs was higher in West than in East Finland. The intake of energy and energy yielding nutrients was greatly dependent on the physical activity but their contributions to the total energy intake were independent. The consumption of minerals and vitamins was adequate in all activity classes. The changes in the diet caused by physical activity seemed to be more quantitative than qualitative.

Food consumption patterns in the 1960s in seven countries.

At the end of the 1950s the Seven Countries Study was designed to investigate the relations between diet and cardiovascular diseases. Sixteen cohorts were selected in Finland, Greece, Italy, Japan, The Netherlands, United States, and Yugoslavia. During the 1960s food consumption data were collected from random samples of these cohorts by use of the record method. In Finland the intake of milk, potatoes, edible fats, and sugar products was very high. A similar but lower intake pattern was observed in The Netherlands. Fruit, meat, and pastry consumption was high in the United States; cereal and alcoholic drink consumption was high in Italy; and bread consumption high in Yugoslavians except for those in Belgrade. In Greece the intake of olive oil and fruit was high and the Japanese cohorts were characterized by a high consumption of fish, rice, and soy products. These differences in food consumption patterns have lessened during the past 25 y.

Symptoms of vibration syndrome and radiographic findings in the wrists of lumberjacks.

In a cross sectional study 279 lumberjacks exposed to chain saw vibration and a reference group of 178 peat bog workers were examined. The mean ages of the two groups were 34.6 and 33.1 years, respectively. The lumberjacks' mean duration of exposure to vibration was 10.4 years. The study consisted of a questionnaire and a clinical examination, including radiographs of the wrists. The prevalence of reported white finger symptoms was 18% for the lumberjacks and 3% for the referents, whereas that of numbness in the upper extremities was 51% and 22%, respectively. Among lumberjacks the occurrence of white finger symptoms increased significantly with the duration of exposure to vibration but was not associated with age or smoking. The prevalence of the numbing of the upper extremities increased linearly with age in both groups, but it was not associated with duration of exposure after adjustment for age. Among lumberjacks there was a significant association between the numbing symptom and the white finger symptom, but not among the referents. A high prevalence of numbing in the upper extremities among the lumberjacks could be at least partly explained by occupational factors other than vibration--work posture, for example. Radiographically, cysts were found in the wrist bones of 8-9% of both groups. The exposure to chain saw vibration no longer seems to be a determinant in the development of vacuoles in the carpal bones.

Dietary prevention of coronary heart disease in women: the Finnish mental hospital study.

A controlled intervention trial, with the purpose of testing the hypothesis that the incidence of coronary heart disease (CHD) could be decreased by the use of a serum-cholesterol-lowering (SCL) diet, was carried out in two mental hospitals near Helsinki in 1959-71. The subjects were hospitalized middle-aged women. One of the hospitals received the SCL diet, ie a diet low in saturated fats and cholesterol and relatively high in poly-unsaturated fats, while the other served as the control with a normal hospital diet. Six years later the diets were reversed, and the trial was continued another six years. The use of the SCL diet was associated with markedly lowered serum cholesterol values. The incidence of CHD, as measured by the appearance of certain electrocardiographic patterns and by the occurrence of coronary deaths, was in both hospitals during the SCL-diet periods lower than during the normal-diet periods. The differences, however, failed to reach statistical significance. An examination of a number of potential confounding variables indicated that the changes in them were small and failed to account for the reduction in the incidence of CHD. Although the results of this trial do not permit firm conclusions, they support the idea that also among female populations the SCL diet exerts a preventive effect on CHD.

Dietary prevention of coronary heart disease: the Finnish Mental Hospital Study.

A controlled intervention trial, with the purpose of testing the hypothesis that the incidence of coronary heart disease (CHD) could be decreased by the use of serum-cholesterol-lowering (SCL) diet, was carried out in 2 mental hospitals near Helsinki in 1959--71. The subjects were hospitalized middle-aged men. One of the hospitals received the SCL diet, i.e. a diet low in saturated fats and cholesterol and relatively high in polyunsaturated fats, while the other served as the control with a normal hospital diet. Six years later the diets were reversed, and the trial was continued another 6 years. The use of the SCL diet was associated with markedly lowered serum-cholesterol values. The incidence of CHD, as measured by the appearance of certain electrocardiographic patterns and by the occurrence of coronary deaths, was in both hospitals during the SCL-diet periods about half that during the normal-diet periods. An examination of a number of potential confounding variables indicated that the changes in them were small and failed to account for the considerable reduction in the incidence of CHD. It is concluded that the use of the serum-cholesterol-lowering diet exerted a substantial preventive effect on CHD.