Immunophysiology of Atlantic sturgeon, Acipenser oxyrinchus oxyrinchus (Mitchill), and the relationship to parasitic copepod, Dichelesthium oblongum (Abilgaard) infection.

The copepod parasite, Dichelesthium oblongum, is known to infect the Atlantic sturgeon, Acipenser oxyrinchus oxyrinchus, within the area near New York city, USA, known as the NY Bight. The gross pathology associated with the juvenile and adult copepod stages along with the parasite's link in causing changes in sturgeon osmoregulatory capabilities has led us to investigate the host immunophysiology in relation to this host-parasite system. All the host variables, which included gill Na(+) -K(+) -ATPase activity, serum alkaline phosphatase (AP) and white blood cell differential counts, were affected in a non-linear manner by the copepod parasite. The parasites increased the host gill Na(+) -K(+) -ATPase activity and serum AP along with the percentage granulocytes while decreasing the percentage lymphocytes. A new method, developed to sample and preserve white blood cells in the field for future flow cytometry analysis, proved adequate. The effects of fish size, location and time of sampling were accounted for by the use of generalized linear models, and their effects on the host variables are discussed.

Flow cytometric comparison of haemocytes from three species of bivalve molluscs.

Haemocyte subpopulations from three bivalve species (the clams Ruditapes philippinarum and Mercenaria mercenaria and the oyster, Crassostrea virginica) were characterised using light-scatter flow cytometry and a standard set of methods. Two parameter (forward and side scatter) plots for the three species were very similar and resembled plots for mammalian white blood cells. Two haemocyte groups (granulocytes and agranulocytes) were found in both the haemolymph and the extrapallial fluid of the clams while those two groups and an additional third group were found in the haemolymph of the oyster. All subpopulations were sorted on to glass slides, identified, photographed, and measured microscopically. Sorting of the bivalve granulocyte and agranulocyte groups indicated varying degrees of heterogeneity within each population in terms of either size or granularity, or both. However, subsorting of selected regions within the major groupings produced highly pure haemocyte populations. The comparison showed both similarities and differences among species. For instance, a distinct subpopulation of small granulocytes was present only in oysters and a subpopulation of spindle-shaped haemocytes, only in M. mercenaria. The haemocyte subpopulations delineated by light-scatter flow cytometry underscore questions about cell lineages, but the instrument also offers a powerful technique for answering them.

Haemocyte parameters associated with resistance to brown ring disease in Ruditapes spp. clams.

Brown ring disease (BRD) is a shell disease caused by Vibrio tapetis. This pathogen disturbs the periostracal lamina causing the appearance of a brown conchiolin deposit on the inner face of the shell, within the extrapallial space. Although differences in resistance to BRD have been documented, their relationship to possible defense functions has never been investigated. In this study, flow cytometry was used to analyze cellular parameters in asymptomatic and experimentally infected Ruditapes philippinarum from France and the west coast of the USA. Parallel analyses were made on Ruditapes decussatus, the native European clam, which is highly resistant to BRD. In the haemolymph and extrapallial fluid of animals without BRD, total haemocyte counts, the percentage of granulocytes, and the phagocytic activity against latex beads or V. tapetis by the haemocytes were significantly higher in American R. philippinarum than in French R. philippinarum. In most cases, levels in R. decussatus were the highest of all three groups. Four weeks following challenge with V. tapetis, BRD prevalence reached 52 in American clams and 100% in French specimens, but only 37% in R. decussatus. In symptomatic animals, phagocytosis of V. tapetis increased significantly in the resistant species of clam, R. decussatus, was unchanged in US clams, and decreased significantly in FR specimens when compared to asymptomatic individuals from each population. Ingestion of V. tapetis by haemocytes in the extrapallial fluid, which is in contact with the periostracal lamina, could be the main defense mechanism used to counter the pathogen. Our results suggest that resistance to BRD may well be related to the concentration of granular haemocytes and the phagocytic activity of haemocytes.

Isolation of the pathogen Vibrio tapetis and defense parameters in brown ring diseased Manila clams Ruditapes philippinarum cultivated in England.

The Manila clam Ruditapes philippinarum was introduced for aquacultural purposes to Europe in the 1970s. In 1987, brown ring disease (BRD), caused by Vibrio tapetis, appeared in clams cultivated in Brouënou (Finistère, France) and later became increasingly widespread and was reported in cultivated and wild clams existing on the Atlantic coasts of France and Spain. The present study reports, for the first time, the presence of BRD in clams cultivated in England. The etiologic bacterium was isolated and identified using bacteriological and serological techniques. The defence response of affected clams was also studied and significant changes in the hematological and biochemical characteristics of hemolymph and extrapallial fluids were demonstrated. Significant mobilization of hemocytes toward the extrapallial fluids, in contact with the main site of infection (mantle-periostracal lamina area), was observed, suggesting a role for these pseudo-internal compartments in the preservation of clam health.

Alterations in hemolymph and extrapallial fluid parameters in the Manila clam, Ruditapes philippinarum, challenged with the pathogen Vibrio tapetis.

In a recent study, we demonstrated the presence of defense factors, competent hemocytes and high enzymatic activities (peptidases, hydrolases, lytic, etc.), in the extrapallial fluid, located between the mantle and the shell, of the Manila clam, Ruditapes philippinarum. In Europe, this species is affected by brown ring disease, an epizootic disease caused by the bacterium Vibrio tapetis. The present work focused on the effect of the development of the disease on cellular and humoral defense parameters in the hemolymph and the extrapallial fluid of experimentally infected clams. Results indicate significant changes in total and dead hemocyte counts, as well as modifications in lysozyme activity and protein content, in the hemolymph and extrapallial fluid of challenged animals. Hemocyte counts and lysozyme activity increased significantly in the hemolymph, but particularly in the extrapallial fluid, where the highest values were observed. A healing (recalcification) process was observed 7 weeks following challenge, suggesting defense system efficiency at neutralizing the pathogen. These results are discussed with emphasis on the role of extrapallial fluids in the defense process against invading microorganisms.

Comparison of high-efficiency and standard haemodialysis providing equal urea clearances by partial and total dialysate quantification.

BACKGROUND: Short-duration high-efficiency haemodialysis has been utilized increasingly in recent years to deliver adequate blood urea clearances per dialysis session. However, high-efficiency and standard-duration haemodialysis schedules, which achieve equal patient urea clearances, may not represent equivalent dialytic therapy due to solute differences in intercompartmental dysequilibrium during dialysis and differences in dialysis mechanics. METHODS: To circumvent the effects of intercompartmental dysequilibrium and postdialysis rebound solute clearances were measured by direct dialysis quantification (total and partial dialysate collections) rather than blood clearances. High-efficiency haemodialysis (dialyser blood flow rate = 400 ml/min; dialysis time = 170.67 min) was compared with standard haemodialysis (dialyser blood flow rate = 200 ml/min; dialysis time = 240 min) performed in random order in six anuric patients using Fresenius F8 dialysers and the same haemodialysis machine. Such haemodialysis schedules were prescribed to provide equivalent urea clearances. RESULTS: Patient plasma water urea clearances measured by direct dialysis quantification were equivalent, whereas high efficiency haemodialysis achieved significantly lower phosphate clearances (P = 0.01), less net bicarbonate absorption (P = 0.01), and lower beta 2 microglobulin removal (P < 0.001) than standard haemodialysis. Estimated total dialysate effluent volumes with partial dialysate collection and total dialysate collection correlated closely (r = 0.95) and there were no differences between patient urea, creatinine and phosphate clearances measured by partial and total dialysate quantification. CONCLUSIONS: The data indicate that even if high-efficiency and standard haemodialysis provide equal whole-body urea clearances, delivered dialysis therapy is not equivalent. The partial dialysate collection method is as accurate as the cumbersome total dialysate collection approach and may be applied to assess delivered dialysis dose by minor modification of current haemodialysis machines.

Skin pigmentation due to minocycline treatment of facial dermatoses.

Fifty-four patients taking minocycline for acne or rosacea were assessed for adverse effects. Their mean duration of treatment was 17 months, and their average cumulative dose was 47 g. No symptoms attributable to the therapy were reported. Biochemistry and haematology profiles were normal. There was no evidence of an adverse effect on thyroid function. Skin pigmentation was detected in eight patients (14.8%). Five patients had diffuse facial pigmentation, and three patients had localized pigmentation at the site of a scar or injury. Diffuse pigmentation occurred only in patients who had been on treatment for 3 years or more; 50% of such patients were affected. Age and solar damage may also have been factors in this type of pigmentation. Localized pigmentation occurred at sites of previous tissue damage, and was not directly related to the duration of therapy. Patients who receive long-term minocycline therapy should be regularly monitored for the development of pigmentation.

Recurrent aphthous ulceration: vitamin B1, B2 and B6 status and response to replacement therapy.

An evaluation of the thiamine, riboflavin and pyridoxine (vitamin B1, B2 and B6) status of 60 patients with recurrent mouth ulcers was performed. Seventeen patients (28.2%) were found to be deficient in one or more of these vitamins. Replacement therapy of these vitamins was given to a study group of deficient patients and a non-deficient group for one month. At the end of therapy and after a follow-up period of 3 months, only those patients who had a B complex deficiency had a significant sustained clinical improvement in their mouth ulcers. Vitamin B1, B2 and B6 deficiencies should, therefore, be considered as another possible precipitating factor in recurrent aphthous ulceration.

Immobilization-related hypercalcaemia--a possible novel mechanism and response to pamidronate.

Immobilization-related hypercalcaemia is an uncommon but important condition being associated not infrequently with both urolithiasis and osteoporosis. In this study 5 patients who had been immobilized for a mean of 3 months and had a mean adjusted serum calcium of 3.15 mmol/l were treated with doses of intravenous pamidronate ranging between 10 mg and 45 mg. All patients became normocalcaemic by day 3. Patients 1-3 mobilized shortly after treatment and remained normocalcaemic. In those patients who continued to be immobile hypercalcaemia recurred after an interval of several weeks. Retreatment with pamidronate again resulted in normocalcaemia. No side effects were noted with treatment. All of the patients studied had increased rates of bone resorption as shown by elevated urinary hydroxyproline/creatinine ratios (median:range) of 0.101:0.045-0.180 (normal less than 0.033) and elevated calcium/creatinine ratios of 2.50:0.69-3.63 (normal less than 0.50). None of the patients in this study had any of the usual risk factors for developing immobilization-related hypercalcaemia though all 5 patients had problems with significant sepsis which we postulate may have lead to cytokine release which in turn contributed to the development of hypercalcaemia. We conclude that pamidronate (at doses as low as 10 mg) is safe and effective in immobilization-related hypercalcaemia and suggest that sepsis should be added to the list of risk factors for development of this syndrome.

Ocular involvement in sinus histiocytosis with massive lymphadenopathy.

Sinus histiocytosis with massive lymphadenopathy is a distinct clinical entity, with ophthalmic involvement in 10% of patients. Orbital as well as eyelid lesions have been described as part of the extra-lymph node involvement of this disorder. We recently examined a young boy with sinus histiocytosis with a bulbar conjunctival mass and chronic dacryocystitis.

Effects of conjugated equine oestrogens with and without the addition of cyclical norgestrel on serum and urine electrolytes, and the biochemical indices of bone metabolism and liver function.

Serum and urine electrolytes, and biochemical indices of bone metabolism and liver function were measured in 51 post-menopausal women treated with two hormone replacement therapy regimens for 24 wk. Twenty-six of the women were treated continuously with conjugated equine oestrogens (0.625 mg/day) and the remainder were treated as above with the addition of norgestrel (0.15 mg/day) during the last 12 days of each 28-day cycle. Both treatment regimens affected electrolytes in a similar manner. The most consistent effect was a reduction in serum sodium levels and a reduction in urinary sodium/creatinine ratios. The combined regimen appeared to have a greater effect on sodium reabsorption. Both regimens decreased all the biochemical indices of bone metabolism measured, viz serum calcium (corrected for albumin), phosphate and alkaline phosphatase and urinary calcium/creatinine and hydroxyproline/creatinine ratios. The preparations used decreased the parameters by similar amounts over the 24 wk indicating that both were equally effective in reducing bone turnover. The data suggested, however, that the combined regimen had a more profound effect on bone metabolism during the early phase of treatment. The two treatment regimens had broadly the same effects on the biochemical indices of liver function, reducing albumin levels and all the liver enzymes. Judging by these indices neither regimen had a deleterious effect on liver function. We conclude that the two hormone replacement regimens have similar effects on the biochemical indices measured, but there are subtle differences between the two treatments which merit further research.

Effective intravenous cyclosporin therapy in a patient with severe Crohn's disease on parenteral nutrition.

We report a patient with severe Crohn's disease and the short bowel syndrome on parenteral feeding who was not responding to conventional therapy and underwent treatment with cyclosporin (CyA) given initially intravenously and subsequently orally in each of two courses. Plasma drug concentrations were largely kept within the therapeutic range but wide variability was observed on oral therapy. Improvement both clinically and by objective assessment, was observed on intravenous CyA therapy, but was not sustained when the drug was given orally for several months. None of the side effects observed resisted treatment or was severe enough to warrant discontinuation of therapy. These findings suggest that there may be a place for intravenous CyA therapy in patients with severe Crohn's disease who do not respond to conventional therapy or to oral treatment with CyA.

Do anticonvulsant drugs commonly induce osteomalacia?

Twenty adult epileptic out-patients who had received anticonvulsant therapy for a mean duration of 15 years were assessed for clinical, biochemical, radioisotopic and bone biopsy evidence of osteomalacia. Occasional biochemical abnormalities were demonstrated but no individual subject was found to have osteomalacia. There is increasing evidence to cast doubt on the existence of a strong relationship between anticonvulsant drugs and osteomalacia. This evidence is reviewed and it is concluded that in the presence of adequate sunlight exposure anticonvulsant therapy alone is most unlikely to lead to osteomalacia in adults.

The significance of the incidental finding of basal ganglia calcification on computed tomography.

Basal ganglia calcification was found as an incidental finding in 42 out of 7000 patients who underwent computed tomography. The calcification showed on plain skull radiography when the maximum density on computed tomography exceeded 100 Hounsfield units. The 26 patients with basal ganglia calcification detected on computed tomography who were available for follow-up, were investigated with matched controls. No clinical features of basal ganglia calcification were noted. Twenty-four patients had no significant metabolic abnormality and two patients had parathyroid disorder identified.