Toxicity thresholds for juvenile freshwater mussels Echyridella menziesii and crayfish Paranephrops planifrons, after acute or chronic exposure to Microcystis sp

Survival of juvenile freshwater mussels (Echyridella menziesii (Gray, 1843) formerly known as Hyridella menziesi) and crayfish (Paranephrops planifrons, White, 1842) decreased after four days exposure to microcystin-containing cell-free extracts (MCFE) of Microcystis sp. at concentrations typical of severe cyanobacterial blooms. Crayfish survival was 100, 80, and 50% in microcystin concentrations of 1339, 2426, and 11146 μg L(-1) respectively, and shade- and shelter-seeking behavior was negatively affected when concentrations were ≥2426 μg L(-1) . Mussel survival decreased to 92% and reburial rates decreased to 16% after exposure for 96 h to MCFE containing microcystins at concentrations of 5300 μg L(-1) . Crayfish survival was 100% when fed freeze-dried Microcystis sp. incorporated into an artificial diet (6-100 μg microcystin kg(-1) ww) at dietary doses from 0.03 to 0.55 μg g(-1) body weight d(-1) for 27 days. Specific growth rate was significantly lower in crayfish fed ≥0.15 μg g(-1) body weight day(-1) compared with controls, but not compared with a diet incorporating nontoxic cyanobacteria. Microcystins accumulated preferentially in crayfish hepatopancreas and mussel digesta as MCFE or dietary concentrations increased. These laboratory data indicate that, assuming dissolved oxygen concentrations remain adequate, and no simultaneous exposure to live Microcystis sp. cells, cell-free microcystins will only be a significant stressor to juvenile crayfish and mussels in severe Microcystis sp. blooms. In contrast, crayfish were negatively affected by relatively low concentrations of microcystins in artificial diets compared with those measured locally in benthic cyanobacterial mats.

Genotype-dependent recovery from acute exposure to heavy metal contamination in the freshwater clam Sphaerium novaezelandiae

The ability to recover from environmental perturbations is essential for the sustainability of ecological systems. Variation in the ability of individual organisms to recover from stressors influences overall resilience at higher levels of biological organisation. Such variation is likely to be genetically based. To investigate this hypothesis we examined the genetic basis of both resistance to and recovery from zinc, a common stormwater contaminant, in the New Zealand freshwater clam Sphaerium novaezelandiae. We undertook a 4-day toxicity test using zinc exposure concentrations ranging from 0.31 to 5.00 mg/L. These concentrations are consistent with levels recorded in urban streams during the first flush of storms. As our response measures we recorded mortality at the end of the 4-day period, as well as reburial rate (time to rebury in sediment) following the 4-day exposure ("exposure") and then again following a 24h period of recovery ("recovery"). Genotypic composition was determined using allozyme electrophoresis, focusing on the enzyme Pgm (phosphoglucomutase). Overall, a significant effect on mortality was observed, with an average value of 78.6% (+/-7.9) at 5.00 mg/L zinc, compared with only 3.8% (+/-3.8) mortality at 0.31 mg/L zinc. An inhibition concentration (IC(50)) of 1.16 mg/L was recorded, when considered regardless of genotypes. There was no significant genotype-specific differences in mortality. There was a significant difference in reburial rates across all genotypes at the end of the exposure period with an average reburial time of 83.0+/-3.6 min at 5.00 mg/L (22.8+/-2.9 min at 0.31 mg/L). There was a near-significant (p=0.058) difference in time taken to rebury when comparing between genotypes at the "exposure" stage for any concentration. Significant differences in reburial rates across all genotypes were also observed following 24h recovery. When individual genotypes were compared at this stage, genotype 33 reburied on average significantly faster (24.0+/-4.5 min) than other genotypes at the highest exposure concentration and was also significantly faster than genotype 44 at 1.25mg/L. Studies investigating the genetic basis to recovery from stressors at an individual level are limited. This study has shown that populations of organisms display genetically-based variation in their ability to recover from zinc exposure in the laboratory and that such variation is linked to a physiological trait (reburial). The potential effects on other life history traits (e.g. feeding), possible physiological trade-offs and the implications for such variation on ecosystem resilience requires further investigation.

Antibody responses to tetanus toxoid and Haemophilus influenzae type b conjugate vaccines following autologous peripheral blood stem cell transplantation (PBSCT)

Accelerated granulocyte and platelet recovery following peripheral blood stem cell transplantation (PBSCT) are well documented. We hypothesize that functional immunity may also be enhanced in PBSCT and performed a phase II trial of immunizations in patients with lymphoma undergoing autologous transplantation with peripheral blood stem cells or bone marrow. Seventeen BMT and 10 PBSCT recipients were immunized at 3, 6, 12, and 24-months post-transplantation with Haemophilus influenzae type b (HIB)-conjugate and tetanus toxoid (TT) vaccines. IgG anti-HIB and anti-TT antibody concentrations were measured and compared between the two groups. Geometric mean IgG anti-HIB antibody concentrations were significantly higher for PBSCT recipients compared to BMT recipients at 24 months post-transplantation (11.3 micrograms/ml vs 0.93 microgram/ml, P = 0.051) and following the 24 month immunization (66.2 micrograms/ml vs 1.30 micrograms/ml, P = 0.006). Similar results were noted for IgG anti-TT antibody with significantly higher geometric mean antibody concentrations in the PBSCT group at 24 months post-transplantation (182 micrograms/ml vs 21.6 micrograms/ml, P = 0.039). Protective levels of total anti-HIB antibody were achieved earlier in PBSCT recipients compared with those of BMT recipients. PBSCT recipients had higher antigen-specific antibody concentrations following HIB and TT immunizations. These results suggest enhanced recovery of humoral immunity in PBSCT recipients and earlier protection against HIB with immunization.

Haemophilus influenzae type b (HIB)-conjugate immunization before bone marrow harvest in autologous bone marrow transplantation

Immune reconstitution following autologous bone marrow transplantation (ABMT) is characterized by defects in B cell and T cell function and loss of specific antibody. In the late post-transplant period, patients are at risk for infections with polysaccharide encapsulated organisms and respond poorly to polysaccharide vaccines. We examined whether immunizing ABMT patients before bone marrow (BM) harvest enhanced the early recovery of specific antibody. Twelve patients were immunized before BM harvest with Haemophilus influenzae type b (HIB)-conjugate, tetanus toxoid and polysaccharide pneumococcal vaccines. Forty-one comparable ABMT patients not immunized prior to BM harvest were also studied. Following ABMT, both groups of patients were immunized with HIB-conjugate and tetanus toxoid vaccines at 3, 6, 12 and 24 months and with pneumococcal vaccine at 12 and 24 months. Patients immunized before BM harvest had higher HIB antibody concentrations during the first 2 years post-transplant, the differences reaching significance at 3 months (P = 0.0001) and following the 24-month dose (P = 0.048). Tetanus toxoid antibody concentrations were also significantly higher at 3 months (P = 0.001) and 6 months (P = 0.032) in patients immunized before BM harvest. There were no differences in pneumococcal antibody concentrations between the two groups. Immunization of patients before bone marrow harvest resulted in higher anti-HIB antibody concentrations following ABMT and may be an effective strategy to prevent infectious complications.

Donor immunization with Haemophilus influenzae type b (HIB)-conjugate vaccine in allogeneic bone marrow transplantation

Bone marrow transplant patients are at increased risk for infections with polysaccharide encapsulated organisms and respond poorly to polysaccharide vaccines. We evaluated the effect of donor immunization with Haemophilus influenzae type b (HIB) polysaccharide-conjugate vaccine on recipient antibody responses following allogeneic bone marrow transplantation. Thirty-two allogeneic transplant patients and their donors were immunized before transplantation with HIB-conjugate, tetanus toxoid and 23-valent pneumococcal vaccines. Following transplantation, patients received HIB-conjugate and tetanus toxoid vaccines at 3, 6, 12, and 24 months and 23-valent pneumococcal vaccine at 12 and 24 months. Thirty-three patients with unimmunized donors were immunized following transplantation in an identical manner. Patients whose donors were immunized had significantly higher total anti-HIB antibody concentrations at 3 months (P = .0001), 6 months (P = .0001), 12 months (P = .0001), and 24 months (P = .002) after transplant compared with patients whose donors were unimmunized. Higher antitetanus toxoid antibody concentrations were also noted in patients with immunized donors, whereas donor immunization with pneumococcal vaccine had no effect on antibody concentrations following transplantation. Donor immunization with HIB-conjugate vaccine resulted in higher antibody concentrations in patients as early as 3 months after allogeneic transplantation and may be an effective strategy to prevent HIB infections.

Pneumococcal conjugate vaccine primes for antibody responses to polysaccharide pneumococcal vaccine after treatment of Hodgkin's disease

Thirty-nine previously treated Hodgkin's disease (HD) patients were immunized with 7-valent pneumococcal conjugate vaccine (7-OMPC) followed by one dose of 23-valent polysaccharide pneumococcal vaccine (23-PS). To determine the priming effect of 7-OMPC vaccine, their antibody responses to six serotypes contained in both vaccines were compared to those of 57 HD patients who received 23-PS vaccine only. The geometric mean antibody concentrations after immunization with 23-PS vaccine were significantly higher for five of the six measured serotypes in HD patients primed with 7-OMPC vaccine compared with responses in HD patients who received 23-PS vaccine only. The mean of the six antibody concentrations was significantly higher for the primed group at 12.5 micrograms/mL and 7.76 micrograms/mL, respectively (P = .015). Priming with a conjugate vaccine should be considered as a strategy to protect high-risk adults.

Antibody responses to polysaccharide and polysaccharide-conjugate vaccines after treatment of Hodgkin disease

OBJECTIVE

To compare the immunogenicity of polysaccharide-conjugate vaccines with that of polysaccharide vaccines in patients previously treated for Hodgkin disease.

DESIGN

All patients were immunized with Haemophilus influenzae type b (HIB)-conjugate and 4-valent meningococcal polysaccharide vaccines. Subgroups of patients were randomly assigned to receive either 23-valent pneumococcal polysaccharide vaccine or a 7-valent pneumococcal-conjugate vaccine that links seven pneumococcal serotypes to the outer membrane protein complex of Neisseria meningitidis.

PATIENTS

144 patients who had completed treatment for Hodgkin disease, which had been diagnosed at least 2 years before the study.

MEASUREMENTS

Antigen-specific antibody concentrations before and 3 to 6 weeks after immunization; number of persons who achieved anti-HIB antibody concentrations considered to be in the protective range.

RESULTS

The geometric mean anti-HIB antibody concentration increased from 1.79 micrograms/mL before immunization to 54.1 micrograms/mL after; the percentage of persons with antibody concentrations in the protective range increased from 62% before immunization to 99% after. Patients immunized with 23-valent pneumococcal vaccine had a geometric mean pneumococcal antibody concentration after immunization (9.15 micrograms/mL) that was similar to that of healthy controls (10.0 micrograms/mL) for the seven serotypes measured. In contrast, patients who received 7-valent pneumococcal-conjugate vaccine had a significantly lower mean response compared with patients who received 23-valent; their geometric mean antibody concentration after immunization was 4.95 micrograms/mL (P = 0.005).

CONCLUSION

A single dose of HIB-conjugate vaccine was immunogenic in patients who had completed treatment for Hodgkin disease diagnosed at least 2 years before immunization. In addition, responses to the 23-valent pneumococcal and 4-valent meningococcal vaccines were equivalent to those seen in healthy controls. Finally, patients had a significantly lower response to a single dose of 7-valent pneumococcal-conjugate vaccine than to 23-valent vaccine.

Plasma lipoproteins and progression of coronary artery disease evaluated by angiography and clinical events

BACKGROUND

There is considerable evidence that remnants of triglyceride-rich lipoproteins may be particularly atherogenic.

METHODS AND RESULTS

Levels of lipoprotein lipids and of apolipoprotein B in low-density lipoproteins were measured in 335 men and women enrolled in a study in which quantitative coronary angiography was carried out at 2-year intervals. Clinical events related to coronary disease occurred in 129 patients during the trial and in the subsequent follow-up period of 4 to 6 years. In multivariate analysis controlled for a number of nonlipid risk factors, high-density lipoprotein cholesterol was inversely related to the mean percentage increase in coronary artery stenosis in both men and women. Neither plasma triglycerides nor low-density lipoprotein cholesterol, triglycerides, or apolipoprotein B was related to change in stenosis, but a measure of remnants of triglyceride-rich lipoproteins, which included cholesterol in intermediate-density lipoproteins, was directly related to lesion progression. The same relations for these measures of plasma lipoprotein concentrations were found to hold for clinical events related to coronary artery atherosclerosis.

CONCLUSIONS

In patients with established coronary heart disease, increased levels of remnants of triglyceride-rich lipoproteins and decreased levels of high-density lipoproteins appear to promote progression of coronary artery atherosclerosis, which in turn may lead to an untoward clinical event. No such relation could be shown for the level of components of low-density lipoproteins. These and other observations call for reevaluation of relations between particular species of lipoproteins containing apolipoprotein B and the pathogenesis of coronary artery atherosclerosis and coronary heart disease.

Evaluation of a 1-year levonorgestrel-releasing contraceptive implant: side effects, release rates, and biodegradability

OBJECTIVE

To determine the release rates, effects on ovulation, and side effects of two lengths of a biodegradable, subdermal contraceptive implant containing levonorgestrel in a caprolactone capsule.

DESIGN

Phase II randomized clinical trial.

SETTING

Public family planning clinic at an urban general hospital.

PARTICIPANTS

Forty-eight healthy, parous, ovulating volunteers.

INTERVENTION

Subjects were randomly assigned either a 2.5- or a 4.0-cm contraceptive capsule that was worn under the skin of the upper arm for 1 year if not removed earlier for other reasons.

MAIN OUTCOME MEASURES

Serum concentrations of levonorgestrel, progesterone, estradiol, and lipoproteins were measured as were metabolic parameters. Vaginal bleeding and other side effects were recorded. After implant removal, remaining levonorgestrel, capsule viscosity, and molecular weight were measured.

RESULTS

The 4-cm implant provided serum concentrations of levonorgestrel ranging from 0.65 ng/mL shortly after insertion to 0.20 ng/mL at 12 months, but the 2.5-cm implant resulted in levels too low for contraception. The 4-cm implant suppressed ovulation in approximately 80% of cycles over 1 year of use, but the 2.5-cm implant failed to suppress ovulation. The implants were rapidly and easily inserted and removed. They retained structural integrity through 1 year of use. Of 48 subjects, 32 had abnormal bleeding patterns; the mean number of days of bleeding per month was 7 with 23 days between episodes. Women using capronor maintained normal metabolic parameters except that low-density lipoprotein decreased slightly.

CONCLUSIONS

The 4.0-cm implant is a promising contraceptive. There were no important metabolic effects, but there were bothersome minor side effects typical of progestin-only contraception.

Relation of plasma lipid and apoprotein levels to progressive intimal hyperplasia after arterial endarterectomy

BACKGROUND

To examine the relation of plasma lipoproteins to the proliferative response after arterial injury in humans, we examined the plasma lipid, lipoprotein, and apoprotein levels of 20 patients with early recurrent stenosis caused by intimal hyperplasia after carotid endarterectomy. These were compared with 20 controls who had no evidence of recurrent stenosis by duplex ultrasound scanning.

METHODS AND RESULTS

By univariate analysis, the reoperated patients had higher levels of plasma cholesterol (251 versus 225 mg/dl, p less than 0.05), total triglycerides (173 versus 105 mg/dl, p less than 0.03), and low density lipoprotein (LDL) apoprotein B (99.8 versus 77.2 mg/dl, p less than 0.003). The ratio of cholesterol to apoprotein B in LDL was lower in patients with restenosis (p less than 0.04), suggesting LDL of smaller diameter. High density lipoprotein (HDL) cholesterol level was reduced (45 versus 55 mg/dl, p less than 0.01) in patients with restenosis. With statistical adjustment for the correlations between these variables by multivariate analysis, both LDL apoprotein B and HDL cholesterol were independent predictors of the risk of restenosis. Ten patients with restenosis but only two controls had one or two apolipoprotein E4 alleles.

CONCLUSIONS

Elevated lipid levels usually associated with an increased risk of atherosclerosis may predispose patients to an increased incidence of intimal hyperplasia after endarterectomy.

Regression of coronary atherosclerosis during treatment of familial hypercholesterolemia with combined drug regimens

We conducted a randomized, controlled trial in 72 patients with heterozygous familial hypercholesterolemia to test whether reducing plasma low-density lipoprotein levels by diet and combined drug regimens can induce regression of coronary lesions. Four hundred fifty-seven lesions were measured before and after a 26-month interval by computer-based quantitative angiography. The primary outcome variable was within-patient mean change in percent area stenosis. Mean low-density lipoprotein cholesterol levels decreased from 7.32 +/- 1.5 to 4.45 +/- 1.6 mmol/L. The mean change in percent area stenosis among controls was +0.80, indicating progression, while the mean change for the treatment group was -1.53, indicating regression (P = .039 by two-tailed t test for the difference between groups). Regression among women, analyzed separately, was also significant. The change in percent area stenosis was correlated with low-density lipoprotein levels on trial. We conclude that reduction of low-density lipoprotein cholesterol levels can induce regression of atherosclerotic lesions of the coronary arteries in patients with familial hypercholesterolemia. The anticipation of benefit from treatment applies to women and men alike.

Sex-related differences in the concentrations of apolipoprotein E in human blood plasma and plasma lipoproteins

Apolipoprotein E (apoE) and lipoprotein cholesterol and triglycerides were measured in blood serum of 272 persons randomly selected from a large industrial population in northern California. Serum apoE level increased linearly by 0.013 mg/dl with each 1 mg/dl increase in very low density lipoprotein (VLDL) triglycerides. This estimate was independent of sex and the use of sex hormones by women. Compositional studies of isolated apoVLDL in 156 hypertriglyceridemic men and 162 normotriglyceridemic persons of both sexes from the same population also indicated that the content of apoE was independent of VLDL level, sex, and hormone use. The estimate of the relationship between serum apoE and VLDL-triglycerides derived from these compositional studies was comparable to that derived by regression analysis. Regression analysis also indicated that only 10-20% of the apoE in the serum of the average person is in the VLDL fraction. Serum apoE levels were 1.4 mg/dl higher in women than in men with the same VLDL-triglyceride level and 1.8 mg/dl lower in women using contraceptive drugs than in nonusers of like age and VLDL-triglyceride level.

Serum apolipoprotein A-I levels: relationship to lipoprotein lipid levels and selected demographic variables

Serum apolipoprotein A-I (apo A-I) and lipoprotein cholesterol and triglycerides were measured in 289 persons randomly selected from a Northern California industrial population in 1974-1976. Apo A-I and high density lipoprotein (HDL) cholesterol were strongly correlates with one another and both were inversely correlated with very low density lipoprotein (VLDL) triglycerides. The decrease in HDL-cholesterol with increasing VLDL-triglycerides was relatively much larger than the concomitant decrease in apo A-I. The relative decrease in the sum of cholesterol and triglycerides in the HDL fraction was similar to that for apo A-I, suggesting that the decreasing HDL-cholesterol:apo A-I ratio with increasing VLDL-triglycerides is due in large part to reciprocal transfer of cholesteryl esters for triglycerides between HDL and VLDL. Mean apo A-I level was 16 mg/dl higher in women not taking exogenous sex steroids than in men, 31 mg/dl higher in women taking estrogens without progestins and 10 mg/dl higher in contraceptive drug users than in other women, and 8 mg/dl higher in black than in white men. The first two of these differences were statistically significant. Apo A-I level was unrelated to age, but increased with ethanol consumption and decreased with adiposity. An inverse relationship between Apo A-I and cigarette smoking was found among women.

Normalization of low-density-lipoprotein levels in heterozygous familial hypercholesterolemia with a combined drug regimen

We studied the effect of th bite acid sequestrant colestipol, alone and in combination with clofibrate or niacin, in patients with heterozygous familial hypercholesterolemia who were given a diet low in cholesterol and saturated fat. With colestipol alone, mean cholesterol levels in serum decreased 16 to 25 per cent. The addition of clofibrate produced a total mean decrement of only 28 per cent. In contrast, serum cholesterol levels fell 45 per cent when colestipol as combined with niacin. Low-density-lipoprotein (LDL) cholesterol decreased 55 per cent with colestipol and niacin, whereas high-density-lipoprotein (HDL) cholesterol increased. Mean LDL cholesterol was lower in patients given this regimen than in matched normal controls eating an unrestricted diet. Tendinous xanthomas, measured by quantitative xeroradiography, were significantly reduced (P < 0.01), indicating that this regimen mobilized cholesterol from tissue pools with slow turnover. Colestipol plus niacin promises to be useful in the treatment of patients at high risk from elevated levels of LDL.

Levels and interrelationships of serum and lipoprotein cholesterol and triglycerides. Association with adiposity and the consumption of ethanol, tobacco, and beverages containing caffeine

We have carried out a cross-sectional multivariate analysis of serum and lipoprotein lipid levels in white persons from an industrial population. Very low density lipoprotein triglyceride level was independent of ethanol consumption but increased with adiposity and cigarette smoking and decreased with coffee-tea drinking. Concomitant age variation in indices of adiposity accounted for only a small part of the sex-specific age trends in triglyceride level. Very low density lipoprotein cholesterol level was independent of all variables considered when controlled for very low density lipoprotein triglyceride. Low density lipoprotein cholesterol covaried with very low density lipoprotein triglyceride among normotriglyceridemic persons. Small increases in low density lipoprotein cholesterol level with adiposity and cigarette smoking appeared to reflect associated increases in very low density lipoprotein triglyceride. Increased low density lipoprotein cholesterol level with age, however, was largely independent of concomitant age variation in very low density lipoprotein triglyceride. High density lipoprotein cholesterol level increased with ethanol consumption and decreased with adiposity and cigarette smoking even after adjustment for its inverse relationship with very low density lipoprotein triglyceride.

Mathematical evaluation of methods for estimation of the concentration of the major lipid components of human serum lipoproteins

The concentration of total cholesterol and triglycerides in the three major lipoprotein classes of human serum was measured in 136 men, randomly selected from an industrial population, by a quantitative method of lipoprotein electrophoresis on agarose gel and of fractions separated by preparative ultracentrifugation. Correlation coefficients for the two estimates were 0.98 for triglycerides in very low-density lipoproteins, 0.93 for total cholesterol in low-density lipoproteins, and 0.75 for total cholesterol in high-density lipoproteins. Data obtained form the analyses of the ultracentrifugal fractions were used to develop regression equations that predict the concentrations of total cholesterol and triglycerides in the lipoprotein classes from their concentrations in whole serum. These equations take into account the inverse curvilinear relationship between total cholesterol in high-density lipoproteins and serum tiriglyceride concentration. When applied to a separate sample of 530 men, the predicted values for triglycerides in very low-density lipoproteins and total cholesterol in low-density lipoproteins correlated as well with ultracentrifugal values as did the electrophoretic estimates. However, for total cholesterol in high-density lipoproteins, the electrophoretic method was superior. Similar regression equations were developed from ultracentrifugal lipoprotein analyses in 158 women from the same industrial population. Although the concentration of total cholesterol in the low-density lipoproteins estimated by both electrophoresis and the regression equations agreed closely in most cases with the ultracentrifugal values, errors exceeded 10% with sufficient frequency to limit the value of the estimates for this purpose. In both men and women, the ratio of total cholesterol to triglycerides in high-density lipoproteins was a hyperbolic function of serum triglyceride concentration, suggesting that cholesteryl esters in the core of this lipoprotein are progressively replaced by triglycerides as the concentration of triglycerides in very low-density lipoproteins increases. This altered composition of nonpolar lipids accounts, at least in part, for the reduction of cholesterol in high-density lipoproteins in hyperlipemic individuals.