Flow cytometric assessments of metabolic activity in bacterial assemblages provide insight into ecosystem condition along the Buffalo National River, Arkansas

The Buffalo National River (BNR), on karst terrain in Arkansas, is considered an extraordinary water resource. Water collected in Spring 2017 along BNR was metagenomically analyzed using 16S rDNA, and for 17 months (5/2017-11/2018), bacterial responses were measured in relation to nutrients sampled along a stretch of BNR near a concentrated animal feed operation (CAFO) on Big Creek. Because cell count and esterase activity can increase proportionally with organic enrichment, they were hypothesized to be elevated near the CAFO. Counts (colony forming units; CFUs) were different among sites for 73 % of the months; Big Creek generated highest CFUs 27 % of the time, with the closest downstream site at 13.3 %. Esterase activity was different among sites 94 % of the time, with Big Creek exhibiting lowest activity 71 % of the time. Over the months, activity was similar across sites at ~70 % active, except at Big Creek (56 %). The α-diversity of BNR microbial consortia near a wastewater treatment plant (WWTP) and the CAFO was related to distance from the WWTP and CAFO. The inverse relationship between high CFUs and low esterase activity at Big Creek (r = -0.71) actuated in vitro exposures of bacteria to organic wastewater contaminants (OWC) previously identified in the watershed. Exponential-phase Escherichia coli (stock strain), Streptococcus suis (avirulent, from swine), and S. dysgalactiae (virulent, from silver carp, Hypophthalmichthys molitrix) were incubated with atrazine, pharmaceuticals (17 α-ethynylestradiol and trenbolone), and antimicrobials (tylosin and butylparaben). Bacteria were differentially responsive. Activity varied with exposure time and OWC type, but not concentration; atrazine decreased it most. Taken together - the metagenomic taxonomic similarities along BNR, slightly higher bacterial growth and lower bacterial esterase at the CAFO, and the lab exposures of bacterial strains showing that OWC altered metabolism - the results indicated that bioactive OWC entering the watershed can strongly influence microbial processes in the aquatic ecosystem.

Population-based case-control study of amyotrophic lateral sclerosis in western Washington State. II. Diet

The association of nutrient intake with the risk of amyotrophic lateral sclerosis (ALS) was investigated in a population-based case-control study conducted in three counties of western Washington State from 1990 to 1994. Incident ALS cases (n = 161) were identified and individually matched on age and gender to population controls (n = 321). A self-administered food frequency questionnaire was used to assess nutrient intake. Conditional logistic regression analysis was used to compute odds ratios adjusted for education, smoking, and total energy intake. The authors found that dietary fat intake was associated with an increased risk of ALS (highest vs. lowest quartile, fiber-adjusted odds ratio (OR) = 2.7, 95% confidence interval (CI): 0.9, 8.0; p for trend = 0.06), while dietary fiber intake was associated with a decreased risk of ALS (highest vs. lowest quartile, fat-adjusted OR = 0.3, 95% CI: 0.1, 0.7; p for trend = 0.02). Glutamate intake was associated with an increased risk of ALS (adjusted OR for highest vs. lowest quartile = 3.2, 95% CI: 1.2, 8.0; p for trend < 0.02). Consumption of antioxidant vitamins from diet or supplement sources did not alter the risk. The positive association with glutamate intake is consistent with the etiologic theory that implicates glutamate excitotoxicity in the pathogenesis of ALS, whereas the associations with fat and fiber intake warrant further study and biologic explanation.

Population-based case-control study of amyotrophic lateral sclerosis in western Washington State. I. Cigarette smoking and alcohol consumption

The associations of cigarette smoking and alcohol consumption with the risk of amyotrophic lateral sclerosis (ALS) were investigated in a population-based case-control study conducted in three counties of western Washington State from 1990 to 1994. Incident ALS cases (n = 161) were identified and were matched to population controls (n = 321) identified through random digit dialing and Medicare enrollment files. Conditional logistic regression analysis was used to compute odds ratios adjusted for age, gender, respondent type, and education. The authors found that alcohol consumption was not associated with the risk of ALS. Ever having smoked cigarettes was associated with a twofold increase in risk (alcohol-adjusted odds ratio (OR) = 2.0, 95% confidence interval (CI): 1.3, 3.2). A greater than threefold increased risk was observed for current smokers (alcohol-adjusted OR = 3.5, 95% CI: 1.9, 6.4), with only a modestly increased risk for former smokers (alcohol-adjusted OR = 1.5, 95% CI: 0.9, 2.4). Significant trends in the risk of ALS were observed with duration of smoking (p for trend = 0.001) and number of cigarette pack-years (p for trend = 0.001). The finding that cigarette smoking is a risk factor for ALS is consistent with current etiologic theories that implicate environmental chemicals and oxidative stress in the pathogenesis of ALS.

Viral meningitis in child care center staff and parents: an outbreak of echovirus 30 infections

OBJECTIVE

A report of five cases of viral meningitis among adults with children enrolled in a child care center prompted an investigation of risk factors for viral transmission from children to adult household members.

METHODS

To determine recent echovirus 30 (E30) infections, the authors conducted a serologic survey. To determine risk factors for infection among adult household members, they conducted a retrospective cohort study using written questionnaires.

RESULTS

Recent E30 infections were found in 84% of children tested, 57% of adult household members tested, and 47% of staff members tested. Infected adults were more likely than infected children to have clinical meningitis. Among adult household members, changing diapers was a risk factor for recent infection. Women who changed > or = 90 diapers per month had a higher infection rate than women who changed fewer diapers; in contrast, men who changed > or = 90 diapers per month had a lower infection rate than men who changed fewer diapers. Handwashing was protective: there was a negative correlation between handwashing after diaper changes and E30 infection among adults with infected children in diapers.

CONCLUSIONS

Because child care centers can be a source of enteroviral infections among adult household members, adults with viral meningitis should be questioned about their children's day care or preschool attendance. The importance of handwashing should be stressed to adults with children in day care.

Differences in bone mineral in young Asian and Caucasian Americans may reflect differences in bone size

Bone mineral content (BMC) and areal bone mineral density (BMD) have been reported to be lower in Asian than in Caucasian adults. To determine if racial differences in bone mass are present in younger subjects and whether they reflect differences in estimated volumetric bone density or in bone size, we compared measurements of bone mineral in healthy young Asian- and Caucasian-American males and females. Bone mineral was measured at the lumbar spine (L2-L4), femoral neck (FN), and whole body (WB) by dual-energy X-ray absorptiometry (DXA) in 99 Asians (49 females, 50 males) and 103 Caucasians (54 females, 49 males) ages 9-26 years. Results were expressed as BMC, BMD, and apparent density (BMAD), an estimate of volumetric bone density that reduces the effect of bone size. Subjects were compared on the basis of chronological age as well as by Tanner stage to correct for potential differences in the timing of puberty. Habitual dietary intake and physical activity were also assessed and correlated with bone mineral. The Asian and Caucasian cohorts differed in body size, diet, and physical activity. Asian females were shorter than the Caucasian females at all stages of puberty and weighed less at pre-/early puberty (p < 0.05). Asian males were older than Caucasians at midpuberty (p < 0.01) and weighed less than the Caucasian males at pubertal maturity (p = 0.001). Asian youths also consumed less calcium and reported less weight-bearing activity. Racial differences were most apparent when comparing BMC data. Asian males had greater spine BMC at midpuberty and lower WB BMC at maturity (p < 0.05). Asian females had lower FN BMC through midpuberty and lower WB BMC in pre-/early puberty (p < 0.05). WB BMD and WB BMC/height values were significantly lower in mature Asian versus Caucasian males. No significant racial differences in BMAD were observed. Multivariate regression analysis indicated that the differences in BMD and BMAD between Asian and Caucasian subjects were largely attributable to differences in weight and pubertal stage, and, at the FN, in weight-bearing activity. Further, the explanatory variables were less strongly associated with BMAD than with BMD. In summary, no significant differences in BMD were found between Asian and Caucasian youths through midpuberty; however, WB BMD and WB BMC/height values were lower in Asian males at sexual maturity. We conclude that observed differences in bone mineral between Asians and Caucasians may be partially attributed to the smaller bone size of Asians.

Antibody response to human cytomegalovirus glycoproteins gB and gH after natural infection in humans

Antibody to the recombinant gB (rgB) and recombinant gH (rgH) glycoproteins of human cytomegalovirus (CMV) was studied in immunocompetent and immunocompromised humans by immunoprecipitating [35S]methionine-labeled CHO cell lines stably expressing rgB and rgH. Antibody to the rgB precursor was present in greater than 60% of immunocompetent individuals. However rgH antibody was detected in less than 10% of these patients. Antibody to both the rgB and rgH was detected during convalescence in three immunocompetent individuals with symptomatic CMV mononucleosis but to a lesser extent in three others who seroconverted to CMV without symptoms. Antibody to rgB and rgH in heart and heart-and-lung transplant recipients was detected in both primary and recurrent CMV infections but not with the same intensity as in immunocompetent individuals. Selected lots of immune serum globulin, administered prophylactically to bone marrow transplant recipients, were frequently deficient in antibody to rgH but not to rgB.

MRI measurement of hepatocyte toxicity using the new MRI contrast agent manganese dipyridoxal diphosphate, a manganese/pyridoxal 5-phosphate chelate

This study reports the first in vivo results using an MR contrast agent manganese dipyridoxal diphosphate (Mn-DPDP) designed to estimate the functional status of the hepatocyte. Thirty New Zealand white rabbits were studied in groups of 5 as follows: No. 1, control, MRI scans only; No. 2 MRI before and up to 90 min following 50 mumol/kg of Mn-DPDP iv; No. 3, rabbits received 9.3 g ethanol/kg and MRI; No. 4, as in No. 3 but following Mn-DPDP; No. 5, MRI as in No. 2 but 18 h. following 1000 mg/kg D-galactosamine used to induce hepatocyte necrosis; and No. 6, rabbits received D-galactosamine and MN-DPDP. In this study significant ethanol- and D-galactosamine-induced hepatocyte damage was indicated by the increased SGPt serum levels in the rabbit. The use of Mn-DPDP allowed detection of early hepatocyte necrosis in these animals whereas conventional spin-echo MRI did not. The fact that D-galactosamine curves with and without Mn-DPDP were not significantly different indicated virtually no membrane transport or metabolism of Mn-DPDP in the liver. Ethanol curves were not normal, but there was still considerable residual Mn-DPDP metabolism. Mn-DPDP appears to be an attractive agent in assessing hepatocyte function.

Comparison of proteins in lacrimal gland fluid secreted in response to different stimuli

To determine if different stimuli cause secretion of different proteins in lacrimal gland fluid (LGF), rabbits were anesthetized and LGF collected under baseline conditions (with the local anesthetic proparacaine), with ocular reflexes present, and in response to arterial injection of the cholinergic agonist acetylcholine (ACh) or the peptide vasoactive intestinal peptide (VIP). Proteins in LGF were separated by nondenatured gradient polyacrylamide gel electrophoresis. Except for minor differences, the number, the approximate molecular weights, and the amounts were the same in LGF secreted in response to four different stimuli. We concluded that the different stimuli caused protein release either from the same secretory cells or from different populations of secretory cells with the same secretory proteins.

Stimulation of rabbit lacrimal gland secretion with biologically active peptides

To determine whether biologically active peptides can stimulate lacrimal gland secretion, we measured fluid and protein secretion from the cannulated lacrimal gland excretory duct of anesthetized rabbits after arterial injection of various peptides. Vasoactive intestinal peptide (VIP, 0.003-3 nmol) and porcine histidine isoleucine-containing peptide (PHI, 0.01-3 nmol) stimulated fluid and protein secretion in a dose-dependent manner. Cholecystokinin octapeptide (CCK-8, 0.01-3 nmol) stimulated fluid but not protein secretion. Neither bombesin nor eledoisin in doses as high as 3 nmol stimulated fluid or protein secretion. When combinations of high or low doses of VIP and the cholinergic agonist acetylcholine (ACh) were injected simultaneously, fluid and protein secretion was additive. We concluded that VIP and PHI stimulated secretion of lacrimal gland fluid and protein, CCK-8 stimulated secretion of fluid, and bombesin and eledoisin did not stimulate either fluid or protein secretion. VIP and ACh, both found in lacrimal gland nerve endings, stimulate lacrimal gland fluid and protein secretion by separate pathways.