Secretion of phospholipase A1 by bone marrow-derived macrophages

Bone marrow-derived macrophages contain phospholipase activity of the A1 and A2 types, active at acid or neutral pH and with different specificities for the fatty acid to be liberated. In contrast to this variety, only one single phospholipase could be detected in extracellular fluids of these cells. Surprisingly, this phospholipase was of the A1 type and active at about pH 8. It exhibited a restricted substrate specificity in that, of the various substrates tested, only phosphatidylcholine containing palmitic acid in position 2 was degraded. This total restriction was not detected with phosphatidylethanolamine substrates. In addition to phospholipase A1, extracellular fluids exhibited lipase activity. A modulation of enzyme secretion could not be achieved by lymphokines or phorbol esters. However, release could be blocked by treating cells with cycloheximide (5 micrograms/ml) or tunicamycin (0.5 micrograms/ml). Phospholipase A1 was also released by thioglycollate-induced peritoneal macrophages.

Welding fumes and chromium compounds in cell transformation assays

Fumes generated from mild steel and stainless steel welding were collected on paper filters and tested in the BHK and SHE cell transformation assays. Fumes from the manual metal arc welding of stainless steel (MMA/SS) had a toxic and transforming effect attributable to their Cr(VI) content. The fumes from metal inert gas stainless steel (MIG/SS) welding also had a toxic effect but this was 2-3 times greater than that expected from their soluble Cr(VI) content based on the activity of soluble Cr(VI) from pure chromium compounds. When collected in an impinger, the fumes from MIG/SS were found to contain approximately 10 times the soluble Cr(VI) content of samples collected on filters. This additional Cr(VI), when collected in a water impinger, also exhibited a greater toxicity compared with that found for the additional Cr(VI) collected in an impinger filled with growth medium. This comparison implies the presence of a short-lived biologically active Cr(VI) species usually lost in conventional sampling techniques. It also implies that there is a detoxification step associated with the formation of Cr(VI) organic complexes. Relatively insoluble Cr(VI) compounds showed a higher toxic and transforming effect in the BHK assay than could be ascribed to the soluble Cr(VI) content of the medium, indicating the importance of phagocytosis as a pathway for the uptake of Cr(VI) and other toxic substances from particulates.

Multiple congenital anomalies, mental retardation and hypogonadotropic hypogonadism in a boy with small marker chromosomes

We report on a mentally retarded boy with hypogonadotropic hypogonadism. He also had a hypoplastic right kidney and right vesicoureteral reflux, blunted calyses of the left kidney, spina bifida occulta, stiff metacarpophalangeal joints, and cataract of the left eye. Chromosome studies showed two marker chromosomes, the larger of which appeared to be a ring chromosome varying greatly in size, while the smaller one remained constant in size. Chromosome abnormalities may be associated with several forms of hypogonadotropic hypogonadism.

Human placental lactogen and dU-estrogen levels in normal twin pregnancies

Reference intervals for human placental lactogen (hPL) and dU-estrogens (dU-E) in uncomplicated twin pregnancies are found to be higher than singleton pregnancies and considerably wider. Significantly more monozygotic than dizygotic pregnancies, and significantly more monoplacental than diplacental pregnancies showed hPL values below the median on the normal range curve. The same was not found for dU-E. Significantly more growth-retarded fetuses were found in monoplacental than diplacental pregnancies. The benefit of measuring the two parameters in order to identify the intrauterine growth retarded fetuses were evaluated in terms of sensitivity and specificity. Both parameters were found less suitable for the purpose.

Comparison of an enzyme-linked immunosorbent assay using crude S. haematobium soluble egg antigen with a radioimmunoassay using purified S. mansoni egg antigen for the serodiagnosis of schistosomiasis haematobium

An enzyme-linked immunosorbent assay (ELISA) using crude Schistosoma haematobium soluble egg antigen (ShSEA) was compared with a radioimmunoassay (RIA) employing purified heterologous species S. mansoni egg antigen (MSA1) for the serodiagnosis of schistosomiasis haematobium in a group of 45 Nigerian school children living in an area endemic for S. haematobium. Both assay systems appeared applicable. The ELISA proved to be more sensitive detecting 100% of the 27 parasitologically positive individuals while the RIA defined 89% of this group. Neither test had false-positive results for the 10 non-endemic area parasitologically negative controls, although the ELISA demonstrated that 56% of the 18 endemic area parasitologically negative controls had anti-ShSEA antibodies. The RIA indicated that 44% of this group had anti-MSA1 antibodies. These latter findings were interpreted as related to the hyperendemicity of schistosomiasis haematobium for the study area.

Ligation of DNA with t(4) DNA ligase

Since they are involved in such important processes as DNA replication, DNA repair, and DNA recombination, DNA ligases can be found in all living cells. Two prokaryotic DNA ligases have become indispensible tools in the fields of in vitro DNA recombination and DNA synthesis. DNA ligase from E. coli is a polypeptide with a molecular weight of 74,000 and is NAD-dependent. T(4) DNA ligase is the product of gene 30 of the T(4) phage, has a molecular weight of 68,000, and is ATP-dependent. Both enzymes catalyse the synthesis of a phosphodiester bond between the 3'-hydroxyl group and the 5'-phosphoryl group at a nick in double-stranded DNA. Of the two enzymes, only T(4) DNA ligase is able to join both DNA fragments with protruding ("sticky ends") as well as DNA fragments with "blunt ends" (1). The reaction takes place in three steps. The first step is the transfer of an adenylyl group of ATP (for T(4) ligase) or NAD (for E. coli ligase) to the free enzyme. It is a side chain NH2 group of a lysine residue that becomes adenylated. During this step, pyrophosphate (T(4) enzyme) or nicotinamide monophosphate (E. coli enzyme) are released.In the second step, the adenylyl group is then transferred to the 5'-phosphoryl end of the DNA and in the third step a phosphodiester bond is formed between a 3'-hydroxyl group and the 5'-adenylated phosphoryl group with the release of AMP. [See also ref. (5) for more detail.].

The nasion-sella reference line in cephalometry: a methodologic study

This investigation was undertaken to examine the effects of the registration error of the nasion-sella reference line (NSL) upon the values of angular and linear head film measurements. A comparison was made between two methods of constructing the NSL: (1) using the anatomically defined landmarks nasion and sella (L method) and (2) using the stable skull structures in the anterior cranial base (S method). Double registrations of sixteen pairs of lateral head films, from before and after 3 years of activator treatment, were performed by two observers. The results of the investigation revealed the following: (1) The registration error of the NSL affected angular and linear head film measures to a considerable degree. (2) The registration error was larger for the S method than for the L method. (3) The two observers differed in locating the NSL. The interobserver difference was especially apparent for the S method. The clinician should be aware of the NSL-registration error in the analysis of both single and serial radiographs. A misjudgment of the position of the reference line may result in diagnostic misinterpretations, thus affecting treatment planning or leading to false conclusions when the outcome of a particular treatment procedure is evaluated. In longitudinal studies covering a short period of growth, the L method would be the method of choice.

Bone lesions in early syphilis detected by bone scintigraphy

We report a case of early syphilis with multiple bone lesions which all resolved after treatment with penicillin. We discuss why bone lesions may be more prevalent than generally believed and why 99m-Tc-MDP-bone scintigraphy is more sensitive than radiography in detecting syphilitic periostitis.

In vitro toxicity and transformation potency of nickel compounds

An in vitro bioassay utilizing BHK-21 cells in culture is used to determine the relative transformation potential of a number of nickel compounds including, as relatively insoluble particulates a known carcinogen (Ni3S2) and several oxides either of commercial interest or found in the working environment in the metal industry (e.g., NiO), and a soluble salt [Ni(CH3COO)2]. Although a wide range of transformation potency is found as a function of the dose of Ni per area of culture, all substances produce the same number of transformed colonies at the same degree of toxicity (e.g., 50% survival). If toxicity is a direct measure of intracellular concentration, then apparently nickel per se is the ultimate transforming agent independent of source or uptake mechanism.

Effects of bromide on behaviour of mice

Groups of mice, housed individually in standard cages placed in a frame especially designed for the recording of locomotive behaviour, were fed diets containing sodium bromide at a level of 0, 400, 1200, 3600 or 10,800 ppm for 36 days. A fully automated system was used to record and process measurements of the nocturnal motility of the mice, together with three other variables (evasion time, spontaneous treadmill performance and body weight), for a total of 128 days before, during and after administration of the test diets. The data obtained, analysed statistically by univariate and multivariate analysis of variance, indicated that for sodium bromide, the 'effect limit' based on behavioural variables and body weight lay for mice between 400 and 1200 ppm in the diet. The fact that the overall effect of the 10,800 ppm dietary level was not completely reversible seemed to be largely attributable to the effect of this level of sodium bromide administration on body weight.

Multiple mononeuritis and radiculitis with erythema, pain, elevated CSF protein and pleocytosis (Bannwarth's syndrome)

Four patients with Bannwarth's syndrome were examined. One to three weeks weeks after the appearance of a large erythematous skin lesion they developed pain of variable localisation. Four days to four weeks later uni- or bilateral facial palsies and other nerve lesions developed. CSF showed elevated protein and mononuclear pleocytosis. There was a defect of the blood-brain barrier and increased intrathecal production of IgG. Facial nerve latencies were increased 4 to 7 times in three cases and normal in one case examined 15 months after onset. Conduction velocity along other nerves was normal apart from slight slowing in one diabetic patient. Recovery was incomplete in three patients 8 to 15 months after onset of disease and complete in one patient after 15 months.

Formaldehyde and hexamethylenetetramine in Styles' cell transformation assay

A dose-dependent increase in the transformation rate in Styles' cell transformation assay using BHK-21/cl.13 cells was observed after exposure to formaldehyde and hexamethylenetetramine. The toxic and transforming effect was equal after exposure to 20 micrograms/ml of formaldehyde or 1000 micrograms/ml of hexamethylenetetramine which is slowly hydrolysed in aqueous solution to form ammonia and formaldehyde.

Use of the Limulus test to determine the hygienic status of milk products as characterized by levels of gram-negative bacterial lipopolysaccharide present

The Limulus test was used to investigate the occurrence of Gram-negative bacterial lipopolysaccharide (LPS) in milk and dairy products. This test specifically detects the extremely heat-resistant LPS, and so determines the total accumulated quantity of LPS in a product whether it has been heat-treated or not. A positive correlation between number of psychrotrophic bacteria and amount of LPS in fresh farm milk was found (r = 0.63). Fresh farm milk and freshly produced market milk contained on average less than 1 ng LPS/ml. The Limulus test is considered highly suitable for use in the dairy industry, being a method which will characterize quickly and specifically the hygienic level of a product by the extent of the cumulative contamination by Gram-negative bacteria.

Mutual pro-drugs of beta-lactam antibiotics and beta-lactamase inhibitors

The principle of combining a beta-lactam antibiotic with a beta-lactamase inhibitor in a single molecule functioning as pro-drug for the two active components is illustrated by the linked esters 3 and 4 in which ampicillin and mecillinam, respectively, are combined with the beta-lactamase inhibitor penicillanic acid sulfone. It is shown that in man these esters are excellently absorbed from the gastro-intestinal tract and after absorption hydrolyzed with simultaneous liberation of the active components. As a result high blood and tissue levels of antibiotic and beta-lactamase inhibitor in a balanced ratio are attained. The advantages of "mutual pro-drugs" over simple combinations are discussed.

Single-pore sensilla of damselfly-larvae: representatives of phylogenetically old contact chemoreceptors?

The four single-pore sensilla on the maxillary palp of Agrion and Ischnura possess two bipolar sensory cells for A-sensilla and five for B-sensilla. Distally, their dendrites are enclosed by a dendritic sheath and a pore tube. The dendritic tips have access to the outside via the opening of the pore tube. The inner dendritic segments join the receptor cell bodies laterally. The receptor cells of each sensillum are enveloped by three sheath cells and three receptor lymph cavities. Receptor lymph cavity 1 and 3 are connected with the outside by the pore tube and a minute canal system in the cuticle, respectively. All three sheath cells show microvilluslike processes of the apical membrane. Moreover, all sheath cells contain two centrioles in tandem arrangement. The structure of the single-pore sensilla is compared with that of similar sensilla of other arthropods. Functional and phylogenetic aspects are discussed.

Method for comparing films and processing procedures in photofluorography

A method for comparing measurements of films and processing procedures is described. A stepped wedge is developed on basis of density measurements in defined areas of chest photofluorographic films. Quality criteria for films and processing procedures are established by systemization of film evaluation. Minor modifications of the method are necessary for application elsewhere in diagnostic radiology.

Diffuse vaginal adenosis. Three cases combined with imperforate hymen and haematocolpos

Diffuse vaginal adenosis is a rare disease presenting severe symptoms and difficult to treat. It has not previously been described in the Scandinavian literature. Three typical cases are reported, two in children of 14 years and one in a women of 20 years, who were all treated for imperforate hymen and haematocolpos. None of the patients had been subjected to oestrogen treatment in utero. The colposcopic findings are very characteristic and are described in relation to the histological examination. The pathogenesis, treatment and risk of malignant transformation are discussed.

Differential effect of subliminal and supralimanl accessory stimulation on task components in problem-solving

The effect of subliminal and supraliminal accessory stimulation on the Stencil Design Test was studied. 30 db below threshold and 35 db above threshold resulted in performance decrement, while 10 db below threshold and 60 db above threshold led to facilitation. Comparison with past research provides evidence that accessory stimulation differentially affects various components of the task.

Order effects in perception of two trapezoidal illusions

2 experiments in which Ss served in more than one condition were performed in order to determine order effects on two perceptual illusions. In the first, expected differences in illusory experiences were a function of complex order effects. In the second experiment, similar order effects significantly influenced the number of illusory experiences reported for three angles of oscillation.