Identification of “Water-Soluble” Toxins Produced by a Stachybotrys atra Strain from Finland

Toxins of a Stachybotrys atra strain from Finland proved to be soluble in a simulated gastrointestinal system. They were purified and characterized as satratoxin H, satratoxin G, and an unknown macrocyclic trichothecene with a molecular ion of 528.     

Fecundity and egg viability in relation to female body size in Neodiprion sertifer (Hymenoptera: Diprionidae)

Relationships between female size and fecundity, egg viability and embryonal development were studied in Neoriprion sertifer. Sawfly females, reared from the 1st instar larvae on Scots pine needles heavily affected by industrial pollutants or on relatively unpolluted needles, were induced to lay eggs parthenogenetically in the field in Finland. Females reared on polluted needles were smaller and oviposited an average of 68.8 eggs, and those reared on unpolluted needles 79.4 eggs per female. However, the higher egg viability in the former group masked the effect of reduced female size. This compensation was primarily related to the size of the females, larger individuals producing relatively fewer viable eggs in both groups.     

Aggressiveness of breast cancers found with and without screening.

OBJECTIVE--To examine how breast cancers found by mammographic screening differ from those found outside screening. DESIGN--Comparative cohort study. SETTING--Turku, southwestern Finland. PATIENTS--126 women aged 40-74 years with breast cancer detected during the first round of mammographic screening in 1987-90 and 125 women within the same age range with breast cancer detected outside screening during the same period. MAIN OUTCOME MEASURES--Primary tumour size, axillary nodal status, histological features, oestrogen and progesterone receptor concentrations, ploidy, and S phase fraction. RESULTS--Compared with the controls women with cancers detected by screening had a smaller primary tumour (57 (46%) screened v 11 (10%) controls had tumours less than or equal to 11 mm in diameter, p less than 0.0001), and less often had axillary nodal metastases (104 (83%) screened v 71 (57%) controls node negative, p less than 0.0001). After adjustment for the smaller size of the primary tumour compared with control cancers, those cancers detected by screening were less likely to have axillary nodal metastases (odds ratio 0.44, 95% confidence interval 0.23 to 0.84), poor histological differentiation (0.20, 0.08 to 0.49), high mitotic counts (0.38, 0.15 to 0.97), tumour necrosis (0.45, 0.22 to 0.93) or to be of the ductal histological type (0.46, 0.22 to 0.95). They had low oestrogen receptor (0.29, 0.12 to 0.70) and progesterone receptor (0.35, 0.17 to 0.92) concentrations less often and had smaller S phase fractions (0.72, 0.55 to 0.96) than control cancers. CONCLUSIONS--Even after adjustment for the smaller size of screen detected breast cancers, their histological and cytometric features suggest low malignant potential. They may also be less likely to metastasise to axillary lymph nodes than cancers found outside screening.     

Location and Distribution of Non-collagenous Matrix Proteins in Musculoskeletal Tissues of Rat

The study assessed immunohistochemically the location and distribution of various non-collagenous matrix proteins (fibronectin, laminin, tenascin-C, osteocalcin, thrombospondin-1, vitronectin and undulin) in musculoskeletal tissues of rat. Fibronectin and thrombospondin-1 were found to be ubiquitous in the studied tissues. High immunoreactivity of these proteins was found in the extracellular matrix of the anatomical sites where firm bindings are needed, i.e. between muscle fibres and fibre bundles, between the collagen fibres of a tendon and at myotendinous junctions, osteotendinous junctions and articular cartilage. Tenascin-C was found in the extracellular matrix of regions where especially high forces are transmitted from one tissue component to the other, such as myotendinous junctions and osteotendinous junctions. Laminin was demonstrated in the basement membranes of the muscle cells and capillaries of the muscle–tendon units. Osteocalc in immunoreactivity concentrated in the extracellular matrix of areas of newly formed bone tissue, i.e. in the subperiosteal and subchondral regions, osteoid tissue and mineralized fibrocartilage zone of the osteotendinous junction. Mild vitronectin activity could be seen in the extracellular matrix of the osteotendinous and myotendinous junctions, and high activity around the bone marrow cells. Undulin could be demonstrated in the extracellular matrix (i.e. on the collagen fibres) of the tendon and epimysium only. However, it was co-distributed with fibronectin and tenascin-C. Together, these findings on the normal location and distribution of these non-collagenous proteins in the musculoskeletal tissues help to form the basis of knowledge against which the location and distribution of the these proteins in various pathological processes could be compared.     

Overexpression of VEGF in Testis and Epididymis Causes Infertility in Transgenic Mice: Evidence for Nonendothelial Targets for VEGF

Vascular endothelial growth factor (VEGF) is a key regulator of endothelial growth and permeability. However, VEGF may also target nonendothelial cells, as VEGF receptors and responsiveness have been detected for example in monocytes, and high concentrations of VEGF have been reported in human semen. In this work we present evidence that overexpression of VEGF in the testis and epididymis of transgenic mice under the mouse mammary tumor virus (MMTV) LTR promoter causes infertility. The testes of the transgenic mice exhibited spermatogenic arrest and increased capillary density. The ductus epididymidis was dilated, containing areas of epithelial hyperplasia. The number of subepithelial capillaries in the epididymis was also increased and these vessels were highly permeable as judged by the detection of extravasated fibrinogen products. Intriguingly, the expression of VEGF receptor-1 (VEGFR-1) was detected in certain spermatogenic cells in addition to vascular endothelium, and both VEGFR-1 and VEGFR-2 were also found in the Leydig cells of the testis. The infertility of the MMTV-VEGF male mice could thus result from VEGF acting on both endothelial and nonendothelial cells of the male genital tract. Taken together, these findings suggest that the VEGF transgene has nonendothelial target cells in the testis and that VEGF may regulate male fertility.     

Free mobilization and low- to high-intensity exercise in immobilization-induced muscle atrophy

After 3 wk of immobilization, the effects offree cage activity and low- and high-intensity treadmill running (8 wk)on the morphology and histochemistry of the soleus and gastrocnemius muscles in male Sprague-Dawley rats were investigated. In both muscles,immobilization produced a significant(P < 0.001) increase in the meanpercent area of intramuscular connective tissue (soleus: 18.9% inimmobilized left hindlimb vs. 3.6% in nonimmobilized right hindlimb)and in the relative number of muscle fibers with pathologicalalterations (soleus: 66% in immobilized hindlimb vs. 6% in control),with a simultaneous significant (P < 0.001) decrease in the intramuscular capillary density (soleus: mean capillary density in the immobilized hindlimb only 63% of that in thenonimmobilized hindlimb) and muscle fiber size (soleus type I fibers:mean fiber size in the immobilized hindlimb only 69% of that in thenonimmobilized hindlimb). Many of these changes could not be correctedby free remobilization, whereas low- and high-intensity treadmillrunning clearly restored the changes toward control levels, the effectbeing most complete in the high-intensity running group. Collectively,these findings indicate that immobilization-induced pathologicalstructural and histochemical alterations in rat calf muscles are, to agreat extent, reversible phenomena if remobilization is intensified byphysical training. In this respect, high-intensity exercise seems morebeneficial than low-intensity exercise.

     

Computer analysis of living cells: movements of the chromatoid body in early spermatids compared with its ultrastructure in snap-frozen preparations

 Quantitative analyses of cytoplasmic and nuclear organelle movements in living interphase cells at defined stages of differentiation are few. By phase contrast videomicroscopy and digital imaging techniques, we have traced the path of the chromatoid body (CB) and analysed its rapidly changing positions in relation to the nuclear envelope, Golgi complex and nuclear pale chromatin areas in living early spermatids of the rat. The CB had intimate interactions with the nuclear envelope and moved both in parallel and perpendicular fashion in relation to it. It had successive short contacts with the Golgi complex and nuclear pale chromatin areas. It was also seen to scan between two pale chromatin areas and it had pinocytosis-like transient engulfments during interactions with the pale chromatin. In ultrastructural analysis of snap-frozen preparations, the CB had a large contact area with the nuclear envelope with several intermediate organelles that may be involved in nucleocytoplasmic material transport. It is evident that quantitative image analysis of living cells is a powerful guide for ultrastructural analyses. The snap-freezing technique gives new possibilities for studies of structures that are sensitive to conventional fixation procedures. Accepted: 23 January 1997     

How many fish populations in Finland are affected by acid precipitation?

Synopsis The number of fish populations affected or lost from small lakes in southern and central Finland due to acid precipitation is estimated. Tolerance limits (pH and labile aluminum) of common fish species were obtained from a fish status survey of 80 lakes. These tolerance values were used to estimate the proportion of affected lakes from the water chemistry data of 783 statistically selected lakes. The proportion of anthropogenically acidified lakes was estimated by calculating pre-acidification pH and aluminum concentrations of the lakes, using a steady-state model based on water chemistry. The number of fish populations for which acidification has affected growth or population structure was estimated at between 2200 and 4400. Out of these, the number of fish populations that have disappeared due to acid precipitation would be about 1000–2000. Almost 60% of the affected or lost populations are roach, Rutilus rutilus, the most sensitive of the common fish species in small lakes in southern and central Finland. Less than 15% of the damaged population is European perch, Perca fluviatilis, the most common species. This is due to the substantially higher tolerance of perch to acidified water in comparison with roach.     

Lipopolysaccharides of polymyxin B-resistant mutants of Escherichia coii are extensively substituted by 2-aminoethyl pyrophosphate and contain aminoarabinose in lipid A

Lipopolysaccharides (LPS) of two polymyxin-resistant (pmr) mutants and the corresponding parent strain of Escherichia Coli were chemically analysed for composition and subjected to ³¹P-NMR (nuclear magnetic resonance) for assessment of phosphate substitution. Whereas the saccharide portions, fatty acids, and phosphate contents were similar in wild-type and pmr LPS, the latter contained two- to threefold higher amounts of 2-aminoethanol. The pmr LPS also contained 4-amino-4-deoxy-l -arabinopyranose (l -Ara_p4N), which is normally not a component of E. coli LPS. This aminopentose has been assigned to be linked to the 4′-phosphate of lipid A. Comparative ³¹P-NMR analysis of the de-O-acylated LPS of the wild-type and pmr strains revealed that phosphate groups of the pmr LPS were mainly (71-79%) diphosphate diesters, which accounted for only 20% in the wild-type LPS. Diphosphate monoesters were virtually nonexistent in the pmr LPS, whereas they accounted for 42% of all phosphates in wild-type LPS. In the lipid A of the pmr strains, the 4′-phosphate was to a significant degree (35%) substituted by l -Ara_p4N, whereas in the wild-type LPS the l -Ara_pN was absent. In the pmr lipid A₁ 2-aminoethanol was completely substituting the glycosidic pyrophosphate but not the glycosidic monophosphate, forming a diphosphate diester linkage at this position in 40% of lipid A molecules. In the wild-type LPS the glycosidic position of lipid A carried mostly unsubstituted monophosphate and pyrophosphate. Thus the polymyxin resistance was shown to be associated, along with the esterification of the lipid A 4′-monophosphate by aminoarabinose, with extensive esterification of diphosphates in LPS by 2-aminoethanol.