Factors associated with profitability in pasture-based systems of milk production.

The global dairy industry needs to reappraise the systems of milk production that are operated at farm level with specific focus on enhancing technical efficiency and competitiveness of the sector. The objective of this study was to quantify the factors associated with costs of production, profitability, and pasture use, and the effects of pasture use on financial performance of dairy farms using an internationally recognized representative database over an 8-yr period (2008 to 2015) on pasture-based systems. To examine the associated effects of several farm system and management variables on specific performance measures, a series of multiple regression models were developed. Factors evaluated included pasture use [kg of dry matter/ha and stocking rate (livestock units/ha)], grazing season length, breeding season length, milk recording, herd size, dairy farm size (ha), farmer age, discussion group membership, proportion of purchased feed, protein %, fat %, kg of milk fat and protein per cow, kg of milk fat and protein per hectare, and capital investment in machinery, livestock, and buildings. Multiple regression analysis demonstrated costs of production per hectare differed by year, geographical location, soil type, level of pasture use, proportion of purchased feed, protein %, kg of fat and protein per cow, dairy farm size, breeding season length, and capital investment in machinery, livestock, and buildings per cow. The results of the analysis revealed that farm net profit per hectare was associated with pasture use per hectare, year, location, soil type, grazing season length, proportion of purchased feed, protein %, kg of fat and protein per cow, dairy farm size, and capital investment in machinery and buildings per cow. Pasture use per hectare was associated with year, location, soil type, stocking rate, dairy farm size, fat %, protein %, kg of fat and protein per cow, farmer age, capital investment in machinery and buildings per cow, breeding season length, and discussion group membership. On average, over the 8-yr period, each additional tonne of pasture dry matter used increased gross profit by €278 and net profit by €173 on dairy farms. Conversely, a 10% increase in the proportion of purchased feed in the diet resulted in a reduction in net profit per hectare by €97 and net profit by €207 per tonne of fat and protein. Results from this study, albeit in a quota limited environment, have demonstrated that the profitability of pasture-based dairy systems is significantly associated with the proportion of pasture used at the farm level, being cognizant of the levels of purchased feed.

Evolution of Carotid Surgical Practice in the last Decade.

Stroke units provide immediate care and appropriate intervention in the evolving stroke. The aims of this study were to review the practice of carotid endarterectomy (CEA) before and after the establishment of a Stroke Unit in St. James's Hospital. Prior to the introduction of the Stroke Unit, 263 CEA's were performed over a five-year period. 139/263 (53%) of these were for symptomatic disease. 229 were performed in the five years since. 179/229 (78%) of these were for symptomatic disease. The 30-day stroke and death rates were < 2% before the introduction of the Stroke Unit, and have remained unchanged. Since the introduction of the Stroke Unit, there has been a slight decrease in the overall number of CEA's performed with a 25% increase in the proportion of endarterectomies performed for symptomatic disease. Despite the reduction in surgery for asymptomatic disease the overall 30-day stroke and death rate remains excellent at 2/229 (2%).

International consensus for a definition of disease flare in lupus.

The Lupus Foundation of America (LFA) convened an international working group to obtain a consensus definition of disease flare in lupus. With help from the Paediatric Rheumatology International Trials Organization (PRINTO), two web-based Delphi surveys of physicians were conducted. Subsequently, the LFA held a second consensus conference followed by a third Delphi survey to reach a community-wide agreement for flare definition. Sixty-nine of the 120 (57.5%) polled physicians responded to the first survey. Fifty-nine of the responses were available to draft 12 preliminary statements, which were circulated in the second survey. Eighty-seven of 118 (74%) physicians completed the second survey, with an agreement of 70% for 9/12 (75%) statements. During the second conference, three alternative flare definitions were consolidated and sent back to the international community. One hundred and sixteen of 146 (79.5%) responded, with agreement by 71/116 (61%) for the following definition: "A flare is a measurable increase in disease activity in one or more organ systems involving new or worse clinical signs and symptoms and/or laboratory measurements. It must be considered clinically significant by the assessor and usually there would be at least consideration of a change or an increase in treatment." The LFA proposes this definition for lupus flare on the basis of its high face validity.

Circannual variation in relative weight of children 5 to 16 years of age.

BACKGROUND: Summer weight gain in children has been reported; however, this is usually based on two time points. Our objective was to investigate monthly variation in weight status. METHODS: Cross-sectional, de-identified health records including height, weight and demographics, collected between 2007 and 2012 from South Central Wisconsin in 70 531 children age 5-16 years were analysed. The monthly averages in body mass index (BMI) z-score were analysed cross-sectionally followed by a paired analysis for a subset with one visit each during school and summer months. RESULTS: BMI z-scores during the summer months (June-August) were lower than values during the school year (September-May). Of note, there was a rapid decrease in BMI z-scores from May to June, with June BMI z-score values being 0.065 units less (95% CI 0.046-0.085) than those in May, little change from June to August and a rapid increase between the August and September BMI z-scores. CONCLUSION: The monthly pattern does not fully agree with previous two-point school-based studies. Results raise concern that the use of two time point measures of BMIs (early fall and late spring) is suboptimal for evaluation of circannual variation. We suggest that future evaluation of the effect of school-based or summer interventions utilizes additional measures in those periods so that a seasonal analysis can be performed.

Future development of lymphoproliferative disorders in patients with autoimmune hemolytic anemia.

The association between autoimmune hemolytic anemia (AIHA) and subsequent appearance of lymphoproliferative disorders (LPDs) has not been properly addressed in large-scale studies. We evaluated 107 patients with idiopathic (67 patients) or underlying (40 patients) immune disorders diagnosed with AIHA between 1992 and 1999. The following variables were examined in univariate and multivariate analysis: age; sex; type of AIHA (warm- or cold-active antibodies); presence of underlying immune disorders; and serum monoclonal protein. Of the 107 patients, 19 (18%) developed malignant LPDS: The median time to develop malignancy was 26.5 months (range, 9-76 months). At multivariate analysis, advanced age (P = 0.005), underlying autoimmune diseases (P = 0.002), and the presence of serum gammopathy (P = 0.045) were risk factors for future development of LPDs in these patients. Also, serum monoclonal IgM protein was a significant predictor (P = 0.0001) for the appearance of LPDs in patients with AIHA. The present study provides evidence that AIHA in some patients should be considered as a precursor of malignant LPDS: Knowledge of certain characteristics may help identify patients at risk for this transformation; periodic clinical and laboratory assessment of these patients is warranted.

Linking electronic health records with community-level data to understand childhood obesity risk.

BACKGROUND: Environmental and socioeconomic factors should be considered along with individual characteristics when determining risk for childhood obesity. OBJECTIVES: To assess relationships and interactions among the economic hardship index (EHI) and race/ethnicity, age and sex in regard to childhood obesity rates in Wisconsin children using an electronic health record dataset. METHODS: Data were collected using the University of Wisconsin (UW) Public Health Information Exchange database, which links electronic health records with census-derived community-level data. Records from 53,775 children seen at UW clinics from 2007 to 2012 were included. Mixed-effects modelling was used to determine obesity rates and the interaction of EHI with covariates (race/ethnicity, age, sex). When significant interactions were determined, linear regression analyses were performed for each subgroup (e.g. by age groups). RESULTS: The overall obesity rate was 11.7% and significant racial/ethnic disparities were detected. Childhood obesity was significantly associated with EHI at the community level (r = 0.62, P < 0.0001). A significant interaction was determined between EHI and both race/ethnicity and age on obesity rates. CONCLUSIONS: Reducing economic disparities and improving environmental conditions may influence childhood obesity risk in some, but not all, races and ethnicities. Furthermore, the impact of EHI on obesity may be compounded over time. Our findings demonstrate the utility of linking electronic health information with census data to rapidly identify community-specific risk factors in a cost-effective manner.

Purification of human basophils using mouse monoclonal IgE.

A method was developed to purify human blood basophils using monoclonal mouse IgE. Enriched suspensions of basophils were sensitized with IgE anti-trinitrophenol (TNP) hapten which was prepared from hybridoma culture supernatants. Rosettes were induced with TNP-coupled red cells and separated from contaminating cells on Percoll gradients. Basophils were dissociated from red cells using cold hypotonic lysis. Using this technique the percentage of basophils was increased from less than 1% to an average of 83.5 +/- 7.8% with a recovery of 58.0 +/- 12.7%. Final purities were highest when enriched sensitized suspensions contained greater than or equal to 10% basophils. Using a radioenzymatic assay, purified basophils were shown to contain an average of 1.3 +/- 0.3 pg histamine. Anti-human, but not anti-mouse IgE, released histamine at an optimal dilution. Using this technique, in 3-4 h, we are able to prepare highly purified suspensions of basophils for further study.

Disseminated intravascular coagulation in solid tumors: clinical and pathologic study.

Disseminated intravascular coagulation (DIC) is a well known hemostatic complication of solid tumors. We evaluated the occurrence of DIC in 1117 patients with solid tumors. Of these patients, 76 (6.8%) were diagnosed with DIC. There were a total of 145 bleeding and clotting episodes reported in the 76 patients. Thrombocytopenia, hypofibrinogemia, elevated D-dimer and fibrinogen degradation products were the most common coagulation abnormalities encountered in patients with DIC. In multivariate analysis, older age (p = .0001), male gender (p = .009), advanced malignancies (p = .027), breast cancer (p = .038) and the presence of necrosis in the tumor specimen (p = .004), emerged as independent factors significantly related to the occurrence of DIC in patients with solid tumors. Of the 76 patients, 25 (33%) achieved response to treatment of DIC as defined in the study. Patients with early stage and advanced malignancies who developed DIC had inferior survival when compared with their counterparts without DIC (p = .039 and p = .005, respectively). Taken together, this study indicates that certain clinical and laboratory features are more common in patients with solid tumors who developed DIC. The occurrence of DIC appears to have an independent effect on survival of patients with cancer. Cooperative studies are encouraged to better address the usefulness and optimal prophylactic heparin regimen in patients at risk for DIC.

Health advisories for consumers of Great Lakes sport fish: is the message being received?

Nationwide, 45 states issue health advisories for sport fish consumers. Chemical contaminants in some Great Lakes (GL) sport fish include compounds suspected of causing adverse reproductive and developmental effects. Although advisories to reduce consumption of contaminated fish, especially by women, have been issued by GL states (i.e., Illinois, Indiana, Michigan, Minnesota, New York, Ohio, Pennsylvania, and Wisconsin) since the mid-1970s, little is known about advisory awareness and GL sport fish consumption in the general population. To estimate the prevalence of GL sport fish consumption and health advisory awareness, we conducted a population-based telephone survey of 8,306 adult residents of the eight GL states. We gathered information concerning respondents' demographic characteristics, fish consumption during the preceding year, and sport fish consumption advisory awareness. The survey response rate was 69%. GL sport fish were eaten during the preceding year by 8.4% -95% confidence interval (CI), 7.6-9.2- of adults in the GL states, approximately 4.7 million persons. Women accounted for 43.9% (CI,39. 4-48.4) of consumers. Although 49.9% of GL sport fish consumers were aware of a health advisory, awareness varied significantly by sex: 58.2% (CI, 51.7-64.7) of males and 39.1% (CI, 32.6-45.6) of females were aware. Using logistic regression, we found awareness associated with male sex -odds ratio (OR) = 2.3; CI, 1.5-3.5), white race (OR = 4.2; CI, 1.9-9.1), college degree (OR = 3.1; CI, 1.3-7.6), and consuming >=24 GL sport fish meals/year (OR = 2.4; CI, 1.4-4.3). Only half of GL sport fish consumers reported awareness of a health advisory concerning eating GL sport fish. Awareness was especially low among women, suggesting the need of targeted risk communication programs for female consumers.

The effects of PCB exposure and fish consumption on endogenous hormones.

Previous studies have suggested that exposure to polychlorinated biphenyls (PCBs) may alter thyroid function, but data on effects of PCB exposure on other endogenous hormones has been lacking. The current study is ancillary to a larger investigation of the effects of Great Lakes fish consumption on PCBs and reproductive function. In the current study we examine associations of PCBs, 1,1-bis (4-chlorophenyl)-2,2-dichloroethene (DDE), and fish consumption with thyroid and steroid hormones in 178 men and PCBs, DDE, and fish consumption with thyroid hormones in 51 women from the original study. Serum PCB level and consumption of Great Lakes fish are associated with significantly lower levels of thyroxine (T(4)) and free thyroxine index (FTI) in women and with significantly lower levels of T(4) in men. Fish consumption, but not PCB level, is significantly and inversely associated with triiodothyronine (T(3)) in men. Results for thyroid-stimulating hormone (TSH) are inconsistent. Among men, there are significant inverse associations of both PCB and fish consumption with sex hormone-binding globulin (SHBG)-bound testosterone, but no association with SHBG or free testosterone. There are no significant overall associations of PCB, DDE, or fish consumption with estrone sulfate, follicle-stimulating hormone, luteinizing hormone, or dehydroepiandrosterone sulfate. The results of this study are consistent with previous studies showing effects of fish consumption and PCB exposure on thyroid hormones and suggest that PCBs may also decrease steroid binding to SHBG. Elucidation of specific mechanisms must await future investigations.

Profiles of Great Lakes critical pollutants: a sentinel analysis of human blood and urine. The Great Lakes Consortium.

To determine the contaminants that should be studied further in the subsequent population-based study, a profile of Great Lakes (GL) sport fish contaminant residues were studied in human blood and urine specimens from 32 sport fish consumers from three Great Lakes: Lake Michigan (n = 10), Lake Huron (n = 11), and Lake Erie (n = 11). Serum was analyzed for 8 polychlorinated dioxin congeners, 10 polychlorinated furan congeners, 4 coplanar and 32 other polychlorinated biphenyl (PCB) congeners, and 11 persistent chlorinated pesticides. Whole blood was analyzed for mercury and lead. Urine samples were analyzed for 10 nonpersistent pesticides (or their metabolites) and 5 metals. One individual was excluded from statistical analysis because of an unusual exposure to selected analytes. Overall, the sample (n = 31) consumed, on average, 49 GL sport fish meals per year for a mean of 33 years. On average, the general population in the GL basin consume 6 meals of GL sport fish per year. The mean tissue levels of most persistent, bioaccumulative compounds also found in GL sport fish ranged from less than a twofold increase to that of PCB 126, which was eight times the selected background levels found in the general population. The overall mean total toxic equivalent for dioxins, furans, and coplanar PCBs were greater than selected background levels in the general population (dioxins, 1.8 times; furans, 2.4 times; and coplanar PCBs, 9.6 times). The nonpersistent pesticides and most metals were not identified in unusual concentrations. A contaminant pattern among lake subgroups was evident. Lake Erie sport fish consumers had consistently lower contaminant concentrations than consumers of sport fish from Lake Michigan and Huron. These interlake differences are consistent with contaminant patterns seen in sport fish tissue from the respective lakes; GL sport fish consumption was the most likely explanation for observed contaminant levels among this sample. Frequent consumers of sport fish proved to be effective sentinels for identifying sport fish contaminants of concern. In the larger study to follow, serum samples will be tested for PCBs (congener specific and coplanar), DDE, dioxin, and furans.

Mesothelioma among employees with likely contact with in-place asbestos-containing building materials.

The occurrence of mesothelioma is a sentinel event in occupational and environmental disease. A mesothelioma surveillance system was established utilizing existing computerized Wisconsin vital statistics data maintained since 1959 and a Cancer Reporting System (CRS) established in 1978. Review of the death certificate listing of usual occupation and industry from 487 mesothelioma deaths in Wisconsin from 1959 to 1989 led to the investigation of 41 persons with likely exposure to inplace asbestos-containing building materials (ACBM): 12 school teachers, 10 school maintenance employees, 7 public building maintenance workers, 5 private building maintenance workers, and 7 commercial and factory workers performing maintenance activities. For 10 (34%) of the 29 maintenance workers the only source of asbestos exposure identified was their maintenance work. For five (17%) histories indicated some prior employment in occupations and industries with probable asbestos exposures. Opportunities for indirect occupational exposure were identified for ten who had been employed in the residential construction industry. One maintenance worker was exposed to asbestos in the household and another had neighborhood exposure. For 9 (75%) of the school teachers, the only identifiable potential source of asbestos exposure was derived from in-place ACBM in schools. One teacher had spent a season in the merchant marine aboard an iron ore-hauling ship and 2 had worked in the residential construction industry. Two of the teachers were sisters, and in two instances, two teachers had taught in the same school facility. We conclude that individuals occupationally exposed to in-place ACBM are at risk for the subsequent development of mesothelioma.

Patterns of venous insufficiency in patients with varicose veins.

The nature and distribution of venous disease surrounding the development of varicose veins and its treatment is controversial. Using duplex ultrasonography, we evaluated 54 lower extremities in 32 patients with varicose veins who were symptomatic and had obvious varicose veins by clinical examination. Twenty-eight percent had greater saphenous trunk incompetence, 2% had lesser saphenous trunk incompetence, and 96% had branch disease. Deep valvular incompetence was seen in 41%, saphenofemoral junction incompetence in 46%, and incompetence of one or more perforators in 46% of the extremities. Thirty-three percent demonstrated no evidence of associated saphenofemoral junction, deep vein, or perforating vein incompetence, while 20% had concurrent saphenofemoral junction, deep vein, and perforating vein incompetence. These data support the heterogeneity of venous disease seen in patients with varicose veins and suggest that surgical therapy be directed to a patient's specific pattern of incompetence rather than routine saphenofemoral junction ligation or stripping of the greater saphenous trunk.

Liver viability after ischemia-reperfusion.

Lack of a reproducible model to quantitatively assess hepatocellular injury following ischemia has made it difficult to assess new strategies for minimizing hepatic injury. We studied the progression of hepatocellular injury after ischemia and ischemia with reperfusion in rats. Irreversible injury was quantitated using a triphenyltetrazolium chloride assay that was shown to correlate with ultrastructural changes. Adenosine triphosphate decreased to 36% of basal values after 30 minutes, but returned to normal with reperfusion with no decrease in viability. In contrast, viability fell by 30% after 60 minutes of ischemia, and by 64% when 60 minutes of ischemia was followed by reperfusion. We conclude that reperfusion of ischemic liver increases the degree of irreversible damage. The model employed here seems to be useful for studying ischemic and reperfusion injury in the liver.

Effects of steroids on the olfactory function of the dog.

Twenty-four (24) mature, mixed breed, healthy dogs weighing from 14.6 kg to 27.6 kg were used to study the effects of various steroids on the olfactory function of the dog using olfactory detection threshold as an index. Two odorants were used, viz; benzaldehyde and eugenol. Of the various steroids used, only dexamethasone produced classical signs of Cushing's syndrome in the dogs. However, all dogs that received either dexamethasone alone or hydrocortisone plus DOCA exhibited a significant elevation in the olfactory detection threshold for both odorants without any observable structural alteration of the olfactory tissue using light microscopy. On the other hand, neither DOCA, hydrocortisone alone, nor any of the vehicles used in the study significantly altered the olfactory function of the dogs. The results show that Cushing's syndrome can be experimentally produced in dogs using exogenous steroids and that this condition diminishes the olfactory capability of the dog without producing classical signs of the disease.

Intrathecal methotrexate-induced megaloblastic anemia in patients with acute leukemia.

OBJECTIVE: To evaluate the occurrence of megaloblastic anemia induced by the infusion of therapeutic or prophylactic methotrexate in patients with acute leukemia. DESIGN: Data on 3 patients with acute leukemia receiving intrathecal methotrexate were prospectively analyzed. SETTING: Large tertiary-care center. RESULTS: All 3 patients with acute leukemia developed megaloblastic anemia confirmed by examination of the bone marrow aspirate and biopsy. Two of the 3 patients had low folic acid levels, while all patients had normal serum B(12) levels. All patients responded favorably to a therapeutic trial of folic acid. The median time for recovery of the hematologic parameters in these patients was 7 days. CONCLUSIONS: Intrathecally administered methotrexate may result in megaloblastic changes in the bone marrow of leukemic patients. The morphologic clues suggestive of folate deficiency in patients with acute leukemia may be masked by coexisting factors, such as the effects of cytotoxic treatment, prior transfusions, or persistent changes from the leukemic clone itself. Caution should be exercised to avoid attributing these changes to the neoplastic process, since the prognosis and treatment for the conditions involved are totally different. Repeat examination of the bone marrow, obtaining folic acid and vitamin B(12) levels, and a therapeutic trial of folic acid may help identify and reverse these changes.

Acquired hemophilia in patients with hematologic malignancies.

OBJECTIVES: To evaluate the occurrence of acquired hemophilia in patients with hematologic malignancies and to assess their response to treatment. DESIGN: Data on 8 patients with hematologic neoplastic disorders and inhibitor against factor VIII were analyzed retrospectively. SETTING: Three large tertiary-care centers. RESULTS: All 8 patients presented with spontaneous or posttraumatic hemorrhages. The mean inhibitor titer at the time of diagnosis was 79 Bethesda units (BU), and residual factor VIII activity was detectable in 3 patients. The inhibitor disappeared in 5 patients after a mean of 92 days, but persisted in the 3 other patients. The patients who achieved complete resolution of their circulating anticoagulant had lower mean inhibitor titers at the time of diagnosis than those who had persistent inhibitor (27 BU vs. 167 BU, respectively). Two patients died as a result of major hemorrhages that did not respond to treatment. CONCLUSIONS: Antibodies against factor VIII may be responsible for some bleeding episodes in patients with lymphoid or myeloid malignancies. Acquired hemophilia in this setting should be differentiated from other causes of bleeding because the approach to treatment is different. No conclusion can be drawn regarding the association between the activity of the underlying illness and the inhibitor titer, although it appears that at least in some patients such a relationship may exist. The underlying pathogenetic mechanisms responsible for the production of autoantibodies against factor VIII remain unclear, but we provide a few explanations in this article.

Dermal cellular responses of helminth-free and Ostertagia ostertagi-infected calves to intradermal injections of soluble extracts from O. ostertagi L3 larvae.

Twelve calves were raised helminth-free until 9 weeks of age when six were orally inoculated with 100,000 Ostertagia ostertagi infective stage larvae (L3). Three uninfected and three experimentally infected calves received intradermal injections of sterile saline and soluble larval extract (SLE) from O. ostertagi L3 with a protein concentration ranging from 1 to 200 micrograms ml-1. Biopsies were performed 48 h post-injection. A kinetic study was performed on the remaining six calves, three infected and three uninfected, using a 100 micrograms ml-1 concentration of SLE and taking biopsies 1, 4, 8, 12, 24, and 72 h post-injection at both the saline and SLE-injected sites. All calves had an immediate wheal and increase in skin thickness at the SLE-injected sites. The numbers of eosinophils infiltrating SLE-injected sites as compared to saline-injected sites were significant in both uninfected and infected calves, but the infected calves had significant numbers to a wider range of SLE concentrations and had significantly higher numbers than uninfected calves in the kinetic study. Infected calves also had significant numbers of basophils in the dose response study at concentrations of 5 and 100 micrograms ml-1 SLE. Neutrophil infiltration was similar in both groups and was significant at SLE-injected sites early in the kinetic study. Detectable mast cells were decreased in SLE-injected sites of infected animals and perivascular accumulation of mononuclear and some polymorphonuclear cells was observed in the deep dermis of infected animals.

Wisconsin farmer cancer mortality, 1981 to 1990: selected malignancies.

Cancer mortality risks for Wisconsin white male farmers were examined during the years 1981 to 1990. Four malignancies were studied: Non-Hodgkin's lymphoma, melanoma, colon cancer, and rectal cancer. Occupation coded deaths were segmented into farmer and nonfarmer groups and population counts for the groups were estimated from 1980 and 1990 Bureau of the Census data. Standardized mortality ratios (SMRs) were constructed from the ratio of observed farmer deaths and the expected number of farmer deaths. Expected deaths were generated from the underlying statewide nonfarmer rate for the malignancy multiplied into the farmer population at risk. Farmers had significantly lower mortality risks for melanoma (SMR: 0.659; 95% CI: 0.993-0.326) and colon cancer (SMR: 0.763; 95% CI: 0.928-0.599). Farmers also exhibited a nonsignificant decrement for non-Hodgkin's lymphoma (SMR: 0.930; 95% CI: 1.214-0.645). For rectal cancer, farmers experienced a slightly higher but essentially the same risk as nonfarmers (SMR: 1.013; 95% CI: 1.418-0.608)--the SMR was not significant. This study corroborates a number of cancer incidence and mortality investigations demonstrating that farmers generally experience the same or lower mortality risks for these malignancies.

Electron multiplier-scintillator detector for pulse counting positive or negative ions.

A general-purpose ion detector has been developed for fast pulse counting in mass spectrometry. It consists of a six-stage electron multiplier joined to part of a scintillator detector. This novel arrangement combines the virtually noiseless pulse-amplification response of an electron multiplier with the bipolar voltage flexibility of a scintillator detector. The resulting hybrid detector is superior in performance to either an electron multiplier or a conventional scintillator detector. It is designed to detect a beam of positive ions or negative ions focused to a line image or to a spot at the focal plane of a mass analyzer. Background counting noise is less than 1 count/min when the detector is used in either the positive ion or negative ion detecting mode. Mass-resolved ions are post-accelerated through an electric field to give them an additional kinetic energy of 10 keV before they strike the ion-to-electron converter in the electron multiplier. This allows low-energy ions to be detected with an efficiency close to unity, over a range of ion masses from 1 amu up to several hundred amu. Randomly spaced pulses can be counted at rates from 0 Hz to 10 MHz. The design of the detector and its operating characteristics are discussed.