First Report of Rapid Blight Caused by Labyrinthula terrestris on Poa annua in Colorado.

A disease characteristic of rapid blight caused by the net slime mold, Labyrinthula terrestris (1,2), was observed on three annual bluegrass (Poa annua) putting greens from a golf course in Adams County, Colorado in April 2009. Symptoms included water-soaked lesions and browning and bronzing of leaves. With microscopic observation, the fusiform cells typically associated with Labyrinthula spp. (1) were detected inside symptomatic leaf tissue. The pathogen was isolated by placing symptomatic leaves on a selective medium modified from Bigelow et al. (1) (12 g of granulated agar [Fisher Scientific, Pittsburg, PA], 10 ml of horse serum [Hema Resource and Supply, Aurora, OR], and 250 µg of ampicillin, streptomycin sulfate, and penicillin G [Sigma, St. Louis, MO] in artificial seawater at 4.0 dS/m electrical conductivity [Instant Ocean, Atlanta, GA]). Irregular-shaped digitate colonies of fusiform cells developed within 1 to 2 days. The isolated organism was then used to fulfill Koch's postulates on 2-week-old Poa trivialis 'Sabre III' seedlings and 4-week-old Poa annua seedlings planted in a 90:10 peat moss/sand mixture in 6-cm-diameter pots. Plants were inoculated with a 9 × 106 cells/ml suspension of L. terrestris cells in artificial seawater (4.0 dS/m) as described by Peterson et al. (2) and irrigated daily with artificial seawater (4.0 dS/m). Negative controls consisted of either P. trivialis or P. annua plants irrigated with artificial seawater only. There were three replications for each treatment and the experiment was repeated for each grass species. Pots were maintained at 28 to 33°C in the greenhouse with ambient light. Within 8 to 10 days of inoculation, 95% of the plants showed symptoms of severe rapid blight, while noninoculated plants showed some minor salt stress symptoms but were otherwise healthy. The organism was successfully reisolated from several plants from each replication using the method described above. Results were the same for all experiments. Rapid blight is frequently associated with high soil salinity (>2.5 dS/m total dissolved salts) (1) and sodium levels above 110 mg/kg (Mehlich-3 extraction) in diagnostic samples. Soil salinity levels from the site affected by the disease were below this guideline. However, sodium levels measured an average of 184 mg/kg. The ability of this pathogen to cause disease on plants growing in soils not measuring high in salinity, and only with elevated sodium, should be considered when attempting to ascertain rapid blight as a cause of turf damage. References: (1) D. M. Bigelow et al. Mycologia 97:185, 2005. (2) P. D. Peterson et al. Online publication. doi:10.1094/ATS-2005-0328-01-RS. Applied Turfgrass Science, 2005.

Diagnosis of turfgrass diseases.

The role of the professional disease diagnostician has become increasingly important in turf management. Responsible turfgrass disease diagnosis must incorporate the possibility of biotic, as well as abiotic, disorders and should consist of three components: the interview, identification of the stress factor, and a management recommendation. The concept of management groups is introduced to facilitate delivery of the rapid and effective solution required by turf managers. Recent advances in diagnostics, including immunoassay, PCR kits, and distance diagnostics, have had minimal effect on turfgrass diagnostic practices to date. However, continued emphasis on the application of technology rather than knowledge-based diagnostic procedures is contributing to the demise of applied plant pathology. Nevertheless, the demand for turfgrass disease diagnostic services continues to increase, making the future for the applied plant pathologist somewhat uncertain, but full of opportunities.

Effect of propranolol and cycloheximide on the ethanol-induced increase in liver tryptophan oxygenase activity in starved rats.

Increased supply of tryptophan to the liver, resulting from the lipolytic action of ethanol, is suggested to be responsible for the increased activity of liver tryptophan oxygenase after ingestion of a single large dose of ethanol. This hypothesis was tested using an antilipolytic drug, propranolol, prior to ethanol treatment. It was found that, while propranolol did inhibit the ethanol-induced increase in blood unesterified fatty acids and free tryptophan concentrations, it did not prevent the activation of tryptophan oxygenase by ethanol. In another experiment, where cycloheximide was used to block protein synthesis, it was found that increased protein synthesis rather than decreased protein degradation is probably responsible for the accumulation of liver tryptophan oxygenase after ethanol ingestion.

First Report of Pyricularia grisea Causing Gray Leaf Spot on Kikuyugrass (Pennisetum clandestinum) in the United States.

Kikuyugrass (Pennisetum clandestinum) is a warm-season turfgrass that has been adopted for use in fairways and roughs in a number of subtropical areas including southern California, Mexico, Australia, and South Africa. During August 2003, a foliar disease of Kikuyugrass was reported from a number of golf courses in southern California. Examination of diseased plants showed the presence of dark, olive green-to-brown lesions on the foliage. Incubation of these plants in a moist chamber for 12 h led to the production of numerous pyriform conidia from these lesions that were characteristic of Pyricularia grisea. Single-spore isolates of the fungus were obtained from infected kikuyugrass samples by transferring conidia to acidified 1.5% water agar and then transferring single, germinated conidia to one-quarter-strength potato dextrose agar. Colony morphology and conidia production were consistent with that described for P. grisea (1). Koch's postulates were performed separately for two single-spore isolates (OSGC-1 and CCCC-1) obtained from infected kikuyugrass. For each isolate, 2-week-old, glasshouse-grown seedlings of kikuyugrass (cv. 'AZ-1') and perennial ryegrass (Lolium perenne) grown in 75-mm pots in soilless media were inoculated with conidia from either OSGC-1 or CCCC-1. For each test, six pots of both kikuyugrass and ryegrass were inoculated, and the tests were conducted three times for each isolate. Conidia were obtained from isolates grown on clarified V8 agar in 100-mm petri plates for 14 days at 25°C. Suspensions were made by adding 10 ml of sterile distilled H2O (sdH2O) to the plates, scraping the surface of the media to dislodge the conidia, filtering the suspension through cheesecloth, and then adjusting the final concentration to 1 × 106 conidia/ml with sdH2O. Seedlings were inoculated with the conidial suspensions with an aerosol applicator, placed in plastic boxes lined with wet paper towels, and sealed to provide adequate moisture for infection. Boxes were incubated at 28°C for 48 h after which time the covers were removed and the plants maintained in ambient glasshouse conditions at approximately 28°C. In all three replicated experiments, kikuyugrass seedlings inoculated with OSGC-1 or CCCC-1 developed symptoms of disease approximately 5 days after inoculation, while inoculated perennial ryegrass did not, even 14 days after inoculation. Symptomatic kikuyugrass leaves were taken randomly from plants from each of the three replicated tests, surface disinfested in 0.3% sodium hypochlorite for 30 s, rinsed with sdH2O, blotted dry, and placed onto acidified water agar in petri plates. Twenty-four hours later, abundant sporulation was observed from symptomatic tissue with conidiophores bearing conidia typical of P. grisea. To our knowledge, this is the first report of gray leaf spot being caused by P. grisea on Pennisetum clandestinum in North America. Reference: (1) M. B. Ellis. Dematiaceous Hyphomycetes. Commonwealth Mycological Institute, Kew, Surrey, UK, 1971.

Ethanol-induced increase in liver tryptophan oxygenase activity in the starved rat: evidence against tryptophan mediation.

A single oral dose of ethanol (4.0 g/kg) increased the activity of liver tryptophan oxygenase in starved male rats. The peak increase of 340% for the total activity and 400% for the holoenzyme activity occurred 6 hr after ethanol administration. At or after these peaks, the levels of tryptophan in plasma and brain but not in liver, decreased significantly. Plasma total tryptophan and brain tryptophan started to decrease significantly as early as 0.5-1.0 hr after the ethanol treatment, while the activity of liver tryptophan oxygenase was still at the control level. These findings suggest that not all the changes in tissue tryptophan concentrations seen after acute ethanol treatment are caused by increased liver tryptophan oxygenase activity. Prior to the increase in liver tryptophan oxygenase activity, an increase of 104 and 50% in plasma corticosterone and free tryptophan, respectively, were seen 15 min after ethanol treatment. However, the increase in liver tryptophan at this time appeared to be small (13%) and statistically insignificant. With tryptophan treatment, the initial peak levels of liver tryptophan and plasma free tryptophan required to stimulate an increase in tryptophan oxygenase activity were 170 times higher than those caused by ethanol. It was therefore concluded that increases in plasma and liver tryptophan after acute ethanol ingestion, probably mediated by the lipolytic action of ethanol, are too small to cause the increase in liver tryptophan oxygenase activity seen after ethanol administration. However, experiments with different corticosterone doses showed that ethanol-induced increases in plasma corticosterone concentrations are high enough to cause an increase in liver tryptophan oxygenase activity.

Ethanol increases rat liver tryptophan oxygenase: evidence for corticosterone mediation.

Acute administration of ethanol (4.0 g/kg) intragastrically or intraperitoneally induced rat liver tryptophan oxygenase (TO) activity 3-4 fold 4-5 hr later. Ethanol administration increased the concentration of plasma free tryptophan and free fatty acids. Pretreatment with a beta-receptor blocker, propranolol, modified the latter responses without affecting the TO induction due to ethanol. The rise of the level of plasma free tryptophan due to ethanol was too small to influence TO activity. Liver tryptophan concentration and TO half-life was unchanged after ethanol administration. Ethanol administration increased the concentration of plasma corticosterone sufficiently to increase TO activity. Pretreatment with a glucocorticoid antagonist blocked this TO response to ethanol. The increased TO activities found after ethanol or corticosterone treatment were influenced in the same manner and to the same extent by cycloheximide. Taken together it is concluded that ethanol induces TO through a rise of glucocorticoid hormones and not by a tryptophan-linked mechanism.

An enzyme-linked immunosorbent assay (ELISA) for prostate-specific antigen.

A sandwich ELISA for human prostate-specific antigen (PSA) is described. Optimal assay conditions, resulting in a sensitive assay with a low background, are presented. The method uses a hyperimmune antiserum produced in the New Zealand white rabbit, against human semen PSA. The IgG fraction of the antiserum was conjugated with horseradish peroxidase and used in the sandwich ELISA method. The anti-PSA IgG showed no cross reactions with saliva, normal blood, female urine, vaginal fluid, or menstrual blood. On occasions, a blood sample showed a non-specific cross-reaction, which was detected by non-immune rabbit IgG. This reaction could be caused by rheumatoid factors, as indicated by experiments with a series of known IgG and IgM rheumatoid antibodies, although other heterophilic antibodies could not be eliminated. The recovery of PSA added to blood plasma, saliva and vaginal fluid was affected by three factors; (a) protein concentration (dilution) of body fluid; (b) nature of the protein; and (c) amount of PSA added.

Suicide with the veterinary drug acepromazine.

A suicide case involving the veterinary drug acepromazine is described. After a single-step liquid alkaline extraction, acepromazine was identified in a chest-cavity blood sample using gas chromatography (GC) with nitrogen-phosphorus (NPD) and mass selective detectors. Acepromazine was then quantitated in the blood and other postmortem tissues by GC with NPD using chlorpromazine as the internal standard. Acepromazine concentrations in the chest-cavity blood, liver, brain, and bile were 0.6, 3.0, 0.4, and 6.5 micrograms/mL, respectively. The stomach contents contained a total of 2.5 mg acepromazine.

First Report of Gray Leaf Spot on Perennial Ryegrass Turf in California.

Gray leaf spot of perennial ryegrass (Lolium perenne L.) turf was first reported in the United States in 1991. The disease epidemic was primarily confined to golf course fairways in southeastern Pennsylvania (1). Subsequently, moderate to severe outbreaks of gray leaf spot occurred in perennial ryegrass fairways and roughs in numerous locations throughout the eastern and midwestern United States. In August 2001, a serious decline of perennial ryegrass turf was observed in a bermudagrass (Cynodon dactylon (L.) Pers) baseball field in Dodger Stadium in Los Angeles, CA, that had been overseeded with perennial ryegrass. The bermudagrass turf was not affected. The perennial ryegrass turf developed necrotic lesions that resulted in blighting of leaf blades. In laboratory assays, Pyricularia grisea (Cooke) Sacc., was consistently isolated from symptomatic ryegrass blades from turf samples collected from the site. Of the 12 P. grisea isolates collected from the assayed leaf blades, five isolates were selected for a pathogenicity assay. Twenty-five 'Legacy II' perennial ryegrass plants were grown from seeds in 4 × 4 in.-plastic pots, (10 × 10 cm) which were filled to 1 cm below the rim with granular calcine clay medium (Turface MVP, Allied Industrial Material Corp., Buffalo Grove, IL). Three weeks after seeding, plants were fertilized with a water-soluble 20-20-20 N-P-K fertilizer (1.3 g/liter of water) once per week. Treatments (isolates of P. grisea and a control) were arranged as a randomized complete block design with five replications. Five-week-old plants were sprayed with an aqueous suspension of P. grisea conidia (≈5 × 104 conidia per ml of sterilized distilled water with 0.1% Tween 20) using an atomizer until the leaves were completely wet. Plants sprayed with sterilized distilled water served as the control. After inoculation, individual pots were covered with clear polyethylene bags and placed in a controlled environment chamber maintained at 28°C and continuous fluorescent light (88 µE m-2 s-1). Four days after inoculation, necrotic lesions (<2 mm diameter) developed on ryegrass blades inoculated with each isolate of P. grisea. Lesions did not develop on leaves of control plants. Seven days after inoculation, the polyethylene bags were removed, and 50 symptomatic blades from each pot were collected, and disease incidence (percent infected leaves) and severity (index 0 to 10; 0 = none, 10 = >90% of the leaf blade necrotic ) were assessed. P. grisea was isolated from symptomatic leaves of plants inoculated with the fungus. Disease incidence and severity on inoculated plants were 92 to 96% and 8.8 to 10, respectively. There were no significant differences in disease incidence and severity (P = 0.05) among the isolates of P. grisea included in the test. To our knowledge, this is the first report of gray leaf spot of perennial ryegrass turf in California. Reference: (1) P. J. Landschoot and B. F. Hoyland. Plant Dis. 76:1280, 1992.

First Report of Gaeumannomyces graminis var. graminis on Kikuyugrass (Pennisetum clandestinum) in the United States.

Kikuyugrass (Pennisetum clandestinum) is a warm-season grass and invasive weed in the landscape, but can be used for golf course fairways in southern California. In 1999, a decline of kikuyugrass was observed on golf courses in southern California beginning in late summer or early autumn. Symptoms included sunken, bleached patches of turf with individual plants having chlorotic foliage and reduced vigor. Roots and stolons were often covered with dark, ectotrophic fungi, and lobed hyphopodia were visible on the stolons. On colonized roots, the cortex was rotted, and the stele showed evidence of colonization by the fungus. In March 2002, a sample of kikuyugrass exhibiting decline symptoms was obtained from a golf course fairway in Los Angeles, CA. Sections of roots and stolons were surface sterilized for 60 s in a 0.3% sodium hypochlorite solution and placed on acidified water agar. Emerging colonies were transferred to potato dextrose agar (PDA). Isolates were characteristic of Gaeumannomyces spp. (2) with dark hyphae and curled colony edges. The rDNA internal transcribed spacer (ITS) regions of two isolates (HCC-5 and -6) were amplified by polymerase chain reaction (PCR) using universal fungal rDNA primers ITS 4 (5'-TCCTCCGCTTATTGATATGC-3') and ITS 5 (5'-GGAAGTAAAAGTCG TAACAAGG-3') (3). PCR products were sequenced and exhibited 99% sequence identity to G. graminis var. graminis (GenBank Accession No. 87685). These isolates were grown separately on autoclaved sand and cornmeal media (1) for 21 days at 25°C. Styrofoam cups were partially filled with autoclaved medium-coarse sand, and 10 g of inoculum was spread evenly in a layer on top. This layer was covered by an additional centimeter of autoclaved sand and 5 g of kikuyugrass seed (cv. 'AZ-1'). Both isolates were tested separately using six replicate cups per isolate. Controls were prepared using only a 10 g layer of autoclaved sand and cornmeal. Cups were misted at 1 h intervals on a greenhouse bench maintained at 25°C. Seeds germinated and emerged after ≈10 days. In cups inoculated with isolate HCC-5 or -6, dark mycelia were evident on the coleoptiles of the emerging plants. Plants were removed and washed 21 days after planting. Inoculated plants were chlorotic and had reduced root and foliar growth compared to the controls. Coleoptiles, hypocotyls, and roots were covered with dark, ectotrophic fungi with lobed hyphopodia present on the hypocotyls. In colonized roots, cortical tissue was rotted with extensive colonization of the epidermis and penetration of the fungus into the root cortex. Sections of infected root tissue were surface disinfested, placed on acidified water agar, and the resulting colonies transferred to PDA. Isolates exhibited the same colony morphology and characteristics as those previously identified as G. graminis var. graminis. To our knowledge, this is the first report of this fungus as a pathogen of kikuyugrass. References: (1) M. J. C. Asher. Ann. Appl. Biol. 70:215, 1972. (2) P. C. Cunningham. Isolation and culture. Pages 103-123 in: Biology and Control of Take All. M. J. C. Asher and P. J. Shipton, eds. Academic Press, London, 1981. (3) T. J. White et al. Amplification and direct sequencing of fungal ribosomal RNA genes for phylogenetics. Pages 315-322 in: PCR Protocols: A Guide to Methods and Applications. M. A. Innis et al. eds. Academic Press, San Diego, CA, 1990.

First Report of a Labyrinthula sp. Causing Rapid Blight Disease of Rough Bluegrass and Perennial Ryegrass.

A Labyrinthula sp. was isolated from symptomatic rough bluegrass (Poa trivialis L.) and perennial ryegrass (Lolium perenne L.) from a golf course in Arizona. Initial symptoms were a water-soaked appearance and rapid collapse of small patches of turf foliage. The affected turf died, and patches coalesced to form large dead areas after several weeks. The symptoms were those of the disease recently termed "rapid blight" for which the causal agent has not been identified (1). Rapid blight was first observed in southern California in 1995 and has become increasingly problematic in 10 other states on several cool-season turfgrasses (1). In Arizona, it is associated with high salinity irrigation water. In microscopic examinations of symptomatic P. trivialis and L. perenne leaf tissue from November 2002 to February 2003, fusiform or spindle-shaped vegetative cells (4 to 5 × 15 to 20 µm) were observed in leaf cells. These cells are consistently associated with rapid blight (1) and are typical in size and shape of those described for Labyrinthula spp. (3,4). The fusiform cells were cultured in 1% horse serum water agar medium made with irrigation water (electrical conductivity [EC] = 3.5 to 4.0 dS/m) from a golf course in central Arizona with rapid blight. The cells readily formed colonies on this medium and exhibited gliding motility along a network of hyaline slime filaments as previously described for the genus Labyrinthula (3,4). Koch's postulates were fulfilled by inoculating P. trivialis and L. perenne seedlings with Labyrinthula sp. isolated from naturally infested P. trivialis in two experiments. The grasses were started from seed and grown as a lawn in containers in the laboratory. Both experiments were repeated once. In the first experiment, infested autoclaved leaf pieces of P. trivialis were used as inoculum. Inoculated leaf pieces were placed within each of several bundles of 4 to 6 leaves and held loosely in place with a 0.5-cm wide ring of tygon tubing. Seedlings were irrigated with sterilized irrigation water from the golf course (EC = 4.0 dS/m). In the second experiment, agar discs from Labyrinthula sp. colonies on 1% horse serum agar were used as inoculum by placing the agar discs in contact with leaves. Seedlings were irrigated with sterile tap water adjusted to 4.0 dS/m using synthetic sea salt (Instant Ocean, Aquarium Systems, Inc., Mentor, OH) Leaf tissue of all inoculated seedlings became water soaked within 3 to 7 days and collapsed within 10 days in both experiments. Fusiform cells were observed in inoculated leaf tissue cells, and the Labyrinthula sp. was reisolated from 100% of selected symptomatic seedlings. Control seedlings treated with noninfested leaf pieces or sterile agar pieces did not develop symptoms, and no fusiform cells were isolated from the leaf tissue. Labyrinthula spp. are usually associated with marine systems (3). Labyrinthula zosterae D. Porter & Muehlst. has been identified as the causal agent in a marine grass wasting disease (2), but to our knowledge, no Labyrinthula spp. have been described as pathogens of terrestrial plants. References: (1) S. B. Martin et al. Phytopathology (Abstr.) 92:(suppl)S52, 2002. (2) L. K. Muehlstein et al. Mycologia 83:180, 1991. (3) K. S. Porkorny. J. Protozool. 14:697, 1967. (4) D. Porter. Handbook of Protoctista. Jones and Bartlett, Boston, MA, 1990.

Estimation of blood alcohol concentrations after social drinking.

Requests for estimates of blood alcohol concentrations (BACs) are often made when blood samples are taken some hours after the time of interest. Many believe that such estimates are not reliable because the subject's alcohol clearance rate is never known and often there is uncertainty as to whether the subject was postabsorptive at the time in question. In order to evaluate the potential errors associated with BAC estimates under these non-ideal conditions, BAC estimates were compared with empirical data obtained from 24 healthy males, ranging in age from 22 to 56 years, who took part in a three hour social drinking session. One blood sample for alcohol analysis was taken from each subject approximately 1 hour after drinking stopped and another was taken approximately 3.5 hours after drinking stopped. Estimations of BACs at the blood sampling time points were made assuming each person had a constant blood alcohol clearance rate in the range of 10 to 20 mg/dL/h (0.01 to 0.02 g/dL/h) over the whole of the experimental period. A variety of methods were used to estimate the volume of distribution for alcohol. All BAC estimations were made assuming complete absorption and full equilibration of the total alcohol dose. The results showed that actual BACs were usually within or very close to the range of "forward" estimates based on the known alcohol doses. Furthermore, most BACs measured about an hour after cessation of drinking were within or very close to the predicted range based on back extrapolation from the actual 3.5 hour BAC result.

Interpreting DNA mixtures.

The interpretation of mixed DNA stains is explained in the context of likelihood ratios. The probabilities for the mixed-stain profile are evaluated under alternative explanations that specify the numbers of contributors and the profiles of any known contributors. Interpretations based simply on the frequencies with which random members of a population would not be excluded from a mixed-stain profile do not make use of all the information, and may overstate the strength of the evidence against included people. The effects of the numbers of contributors depends on whether all the alleles at a locus are present in the mixed stain. A general equation is given to allow likelihood ratios to be calculated, and includes the "2p" modification suggested by the 1996 NRC report. This modification is not always conservative. A computer program to perform calculations is available.

Behavior of animal blood in blood typing systems. Isoelectric focusing of erythrocyte acid phosphatase and phosphoglucomutase.

Isoenzyme band patterns of animal blood erythrocyte acid phosphatase (EAP) and phosphoglucomutase-1 (PGM) were studied by isoelectric focusing on ultrathin polyacrylamide gels. For blood from all animals tested (dog, cat, cow, sheep, and goat), the overall band patterns for both isoenzymes were different from those of the most common human types of these enzymes, although some animal EAP and PGM bands appeared in the human band areas. When mixtures of human and animal red blood cells were studied, it was found that misinterpretation of human types was possible only if the overall band pattern of the mixtures was ignored. For the animal blood tested, the strong PGM bands appearing outside the human band areas could be used as "markers" for the possible presence of animal blood in the samples tested.

The influence of some methodological factors on measurement of tryptophan oxygenase activities in crude homogenates of rat liver.

1. With two different methods for assaying the tryptophan oxygenase activity in rat liver homogenates, the effects of some methodological factors on the activity of the enzyme were studied. 2. In fed, but not in starved, rats a compound(s) absorbing at 365 nm, interfering with the reading of kynurenine absorbance, disappeared gradually during incubation. 3. A correction for this tryptophan-independent reaction was necessary in order to determine correct tryptophan oxygenase activity. 4. Blood remaining in liver tissue post mortem can serve as a source of cofactor haem for tryptophan oxygenase, causing spuriously high values for the activity of the holoenzyme form of tryptophan oxygenase. 5. A rapid and progressive activation of tryptophan oxygenase post mortem occurs in undisrupted liver tissue, and this activation is temperature-dependent.

Portable device for preparation and delivery of gas mixtures.

A simple, portable device for the preparation and delivery of gas mixtures has been designed and constructed. The basic feature of the device is the use of gas flow controllers to maintain stable flow rates over a wide range of downstream pressures, instead of the capillary tubes and water-filled barostats commonly used in gas-mixing devices. Elimination of the barostat avoids problems such as water leakage, the loss of gases through the barostat, and changes in gas pressure due to evaporative loss of water from the barostat. The absence of a barostat also provides a closed system, allowing the use of the device for mixing and delivering of toxic gases. The prototype of the device has been used to prepare mixtures of different gases for more than 1 year and has been found to operate consistently and reproducibly. The actual concentrations of O(2), CO(2), and N(2) in gas mixtures (determined by gas chromatography) immediately after mixing were between 2.2 and 6.6% of the desired values in four performance tests. Fluctuations in concentration of gases in mixtures after 9 days of continuous gas delivery was less than 2% in four performance tests.

Comparison of serum beta-hexosaminidase isoenzyme B activity with serum carbohydrate-deficient transferrin and other markers of alcohol abuse.

We have compared beta-hexosaminidase (beta-Hex) activity, carbohydrate-deficient transferrin (CDT), mean corpuscular volume (MCV), gamma-glutamyltransferase (GGT), aspartate aminotransferase (AST) and alanine aminotransferase (ALT) values in serum from male alcoholic patients with the corresponding values in moderate and non-drinking subjects. The total beta-Hex activity was 2.5 times higher in the alcoholics than in the moderate drinkers and this increase was mainly due to a 5-fold increase in the activity of the B-isoform of the enzyme. This was expressed as a percentage of the total beta-Hex activity and called 'beta-Hex B%'. Strong correlations were found between alcohol consumption (g/ day) and beta-Hex B% (r = 0.757, P < 0.001, n = 42), alcohol consumption and CDT (r = 0.671, P < 0.001, n = 42), and beta-Hex B% and CDT (r = 0.628, P < 0.001, n = 57). Serum beta-Hex B% had a sensitivity of 94% and a specificity of 91% in detecting alcoholic drinking of > 60 g/day. As a single marker of alcoholic drinking, it was markedly more sensitive than MCV and the liver enzymes GGT, AST and ALT, and slightly more sensitive than serum CDT (94 vs 83%). At the CDT cut-off level of 20 U/l, 17% of the moderate and non-drinkers would have been classified as alcoholic drinkers and 17% of the alcoholics would have been classified as moderate drinkers. Some of these misclassifications were eliminated if the beta-Hex B% results were taken into account. We suggest that serum beta-Hex B% can be a useful and inexpensive laboratory test for alcohol abuse.