The characterization of algal and microbial mucilages and their aggregates in aquatic ecosystems

The mucilage 'phenomenon' of marine waters, a sporadic but massive accumulation of gelatinous material at and below the water surface, can create serious environmental and economic problems. To address these problems, we must understand better the causes of the phenomenon, its modulation by environmental factors and its adverse effects on ecosystems. In the context of an improved understanding, this brief review describes the means to characterize mucilage types and mucilage aggregates in their native condition, or as close to native as state-of-the-art technology will permit. Biological, chemical and physical factors interact to determine mucilage 'speciation' and thus the specific properties of mucilaginous materials. These factors and their interactions are described briefly in relation to the molecular biology of mucilage synthesis, the formation of submicroscopic 'particles' of mucilage and the morphology of mucilage aggregates. To facilitate current attempts to relate mucilage fine structure to the macroscale morphology of large aggregates (e.g., as found in the Adriatic Sea), attention will be focused on the 'fibril', a ribbon-like colloid rich in polysaccharide molecules. Such colloids (submicrometre particles) present many morphotypes which are identifiable by transmission electron microscopy; several fibril types appear as basic structural units in many kinds of mucilage aggregates in aquatic ecosystems. Attention will also be focused on (1) the problems of coping with analyzing mixtures of highly-hydrated, physically-unstable materials and (2) the detection, assessment and minimization of colloid instability artifacts which have confounded morphological analyses of mucilage aggregates in the past.     

Structural changes in the tissues of white rats after capsaicin administration

Attitudes to health and illness may differ between rural and urban dwellers. Issues that may relate to the provision of health services to rural dwellers are raised for consideration. The response of urban dwellers to illness or disability has often been linked to discomfort caused by pain or cosmetic attractiveness, while for rural dwellers the response to illness or disability is often related to the degree to which the illness or disability affects productivity. Often the rural resident will postpone seeking medical or associated services until it is economically or socially convenient. The notion of exposing their private lives to strangers or acquaintances from the local based services or to undertake the journey to distant services where the cultural or behavioural differences could be misunderstood, may impact on rural dwellers' well-being. Health service providers in rural areas need to understand such differences and difficulties when offering services.     

Myocardial perfusion study in patients with right bundle branch block]

Children with acute otitis media (AOM), aged 2-12 years, were randomised to 10 days treatment with amoxycillin/clavulanate (A/C) 70/10 mg/kg/day given b.i.d. (231 patients) or to A/C 60/15 mg/kg/day given t.i.d. (232 patients). Clinical success rates at end of therapy (10-17 days) were 91.8% for the b.i.d. group and 90.5% for the t.i.d. group and at follow-up (28-42 days) were 80.1% for the b.i.d. group and 77.6% for the t.i.d. group, indicating that the b.i.d. regimen was as effective as the t.i.d. regimen. There was no statistically significant difference in incidence of adverse experiences between the two groups. The overall incidence of protocol defined diarrhoea assessed from diary booklets was low, with a lower incidence in the b.i.d. group (6.7%) than in the t.i.d. group (10.3%). Significantly more patients in the b.i.d. group (83.1%) than in the t.i.d. group (72.8%) had at least 80% compliance over a 7-10 day treatment period. A/C given twice or three-times daily was highly effective in the treatment of AOM in children. The two regimens showed equivalent clinical efficacy, both were well tolerated, and there was evidence of improved compliance with the b.i.d. regimen.     

Skip lesions in temporal arteritis

Although isolated foci of arteritis ("skip lesions") are presumed to occur in temporal arteritis, there is little documentation of their existence or significance. We have identified skip lesions in 17 of 60 patients (28%) with temporal arteritis, based on a retrospective and prospective examination of temporal artery biopsy specimens. By examining more than 6,000 serial sections of arteries from patients with skip lesions, we have found foci or arteritis as short as 330 mu in length in an otherwise normal biopsy specimen. Our study emphasizes the need to biopsy long segments of artery, to examine multiple histologic sections, and to perform a contralateral temporal artery biopsy when frozen-section examination of the first side is normal.     

Interaction of A-nor, A, 19-dinor, and A-homo-5 alpha-androstane derivatives with the androgen receptor and the epididymal androgen-binding protein

The equilibrium affinity constant for rat prostate androgen receptor and epididymal androgen binding protein (ABP) has been determined for thirty-four potential progestogens. Three A-nor-, four A,19-dinor-, and one A-homo-5 alpha-androstane derivative bind to the androgen receptor (KD less than 0.5 muM). Five of these compounds also bind to ABP with an affinity of the same order of magnitude. "Anordrin" (compound 24) and "Dinordrins" (compounds 10, 14, 15, 16, 17), which are potential female contraceptives, do not bind with high affinity to the androgen receptor or to ABP. The following modifications in A-nor derivatives favour binding to the receptor as compared to ABP: 19-nor substitution (compound 1), C-18 methyl homologation (compound 5), 2 alpha-ethinylation (compound 22). One 2 alpha-allenyl A-nor derivative (compound 25) and one A-homo derivative (compound 34) bind almost exclusively to ABP. The interaction with either binding protein is decreased by oxidation or esterification of the hydroxyl group at C-17, and by addition of a 17 alpha-ethinyl group. The latter modifications are likely to increase the specificity of androstane derivatives for receptors other than androgen binding proteins, such as the progesterone receptor.     

Bryostatin 1 activates splenic lymphocytes and induces sustained depletion of splenocyte protein kinase C activity in vivo after a single intravenous administration

The aim of the study was to evaluate a range of W/O semisolid emulsion systems (creams) containing white soft paraffin (petrolatum) and a new type of nonionic lipophilic silicone emulsifier (Abil EM 90) using a novel combination of rheological tests. Emulsifier concentrations from 1.5% to 3.0% w/w were used with two manufacturing procedures, cold (25 degrees C) and warm (70 degrees C) emulsification, to determine whether and to what extent these variables alter the structure and consistency of the creams. The techniques comprised linear (continuous flow) and dynamic (oscillatory) rheometry at 25 degrees C, thermal flow experiments (from 10 degrees to 90 degrees C and back to 10 degrees C), and penetrometry studies. The differences in emulsifier concentration produced effects on the rheological properties of the W/ O creams, although the manufacturing process was much more influential. Cold emulsification led to creams with higher viscosity, lower thixotropy, and better elastic properties. The results of penetration tests on creams correlated with those of the rheological studies. The flow properties of white soft paraffin at 25 degrees C were comparable with the creams obtained by cold emulsification, while the elasticity was considerably lower. Thermorheological studies showed evidence for transitional behavior for white soft paraffin on heating, but not for the creams. White soft paraffin showed a higher viscosity (and resistance to the penetrating force) when melted at 70 degrees C and left to solidify at room temperature, compared to the "unmelted" sample. This was the opposite trend to that found with warm and cold emulsified creams. The input of heat during the emulsification process showed a strong effect on the structure and consistency of the W/O creams containing petrolatum and silicone emulsifier, resulting in a less viscous product. The use of the aforementioned techniques represents a useful and novel approach to the evaluation of cream consistency.     

Measurement of blood volume and red cell mass: re-examination of 51Cr and 125I methods

Comparison of results of red cell mass (RCM) measurement by 51Cr and 125I methods in 119 patients showed virtual equivalence. Both methods have an acceptable coefficient of variation (CV) that is < 5%. The 125I method is simpler and much less expensive. Unrealistically narrow "normal ranges" for RCM are likely to lead to misdiagnosis of polycythemia vera. Upper normal limits of 39 mL/kg (males) and 32 mL/kg (females) are consistent with originally published data in normal persons; use of these limits as criteria would reduce the risk of misdiagnosis. No cases of "stress erythrocytosis" or Gaisbock Syndrome were encountered among the 119 cases reviewed.