Long-term exposure to air pollution and COVID-19 severity: A cohort study in Greater Manchester, United Kingdom

Exposure to outdoor air pollution may affect incidence and severity of coronavirus disease 2019 (COVID-19). In this retrospective cohort based on patient records from the Greater Manchester Care Records, all first COVID-19 cases diagnosed between March 1, 2020 and May 31, 2022 were followed until COVID-19 related hospitalization or death within 28 days. Long-term exposure was estimated using mean annual concentrations of particulate matter with diameter ≤2.5 μm (PM_2.5), ≤10 μm (PM₁₀), nitrogen dioxide (NO₂), ozone (O₃), sulphur dioxide (SO₂) and benzene (C₆H₆) in 2019 using a validated air pollution model developed by the Department for Environment, Food and Rural Affairs (DEFRA). The association of long-term exposure to air pollution with COVID-19 hospitalization and mortality were estimated using multivariate logistic regression models after adjusting for potential individual, temporal and spatial confounders. Significant positive associations were observed between PM_2.5, PM_10, NO_2, SO_2, benzene and COVID-19 hospital admissions with odds ratios (95% Confidence Intervals [CI]) of 1.27 (1.25-1.30), 1.15 (1.13-1.17), 1.12 (1.10-1.14), 1.16 (1.14-1.18), and 1.39 (1.36-1.42), (per interquartile range [IQR]), respectively. Significant positive associations were also observed between PM_2.5, PM₁₀, SO₂, or benzene and COVID-19 mortality with odds ratios (95% CI) of 1.39 (1.31-1.48), 1.23 (1.17-1.30), 1.18 (1.12-1.24), and 1.62 (1.52-1.72), per IQR, respectively. Individuals who were older, overweight or obese, current smokers, or had underlying comorbidities showed greater associations between all pollutants of interest and hospital admission, compared to the corresponding groups. Long-term exposure to air pollution is associated with developing severe COVID-19 after a positive SARS-CoV-2 infection, resulting in hospitalization or death.

A comparison of experience sampled hay fever symptom severity across rural and urban areas of the UK

Hay fever affects people differently and can change over a lifetime, but data is lacking on how environmental factors may influence this. This study is the first to combine atmospheric sensor data with real-time, geo-positioned hay fever symptom reports to examine the relationship between symptom severity and air quality, weather and land use. We study 36145 symptom reports submitted over 5 years by over 700 UK residents using a mobile application. Scores were recorded for nose, eyes and breathing. Symptom reports are labelled as urban or rural using land-use data from the UK's Office for National Statistics. Reports are compared with AURN network pollution measurements and pollen and meteorological data taken from the UK Met Office. Our analysis suggests urban areas record significantly higher symptom severity for all years except 2017. Rural areas do not record significantly higher symptom severity in any year. Additionally, symptom severity correlates with more air quality markers in urban areas than rural areas, indicating that differences in allergy symptoms may be due to variations in the levels of pollutants, pollen counts and seasonality across land-use types. The results suggest that a relationship exists between urban surroundings and hay fever symptoms.

UK daily meteorology, air quality, and pollen measurements for 2016-2019, with estimates for missing data

In recent years, quantifying the impacts of detrimental air quality has become a global priority for researchers and policy makers. At present, the systems and methodologies supporting the collection and manipulation of this data are difficult to access. To support studies quantifying the interplay between common gaseous and particulate pollutants with meteorology and biological particles, this paper presents a comprehensive data-set containing daily air quality readings from the Automatic Urban and Rural Network, and pollen and weather data from Met Office monitoring stations, in the years 2016 to 2019 inclusive, for the United Kingdom. We describe (1) the sources from which the data were collected, (2) the methods used for the data cleaning process and (3) how issues related to missing values and sparse regional coverage were addressed. The resulting data-set is designed to be used 'as is' by those using air quality data for research; we also describe and provide open access to the methods used for curating the data to allow modification of or addition to the data-set.

Accurate Prediction of Organic Aerosol Evaporation Using Kinetic Multilayer Modeling and the Stokes-Einstein Equation

Organic aerosol can adopt a wide range of viscosities, from liquid to glass, depending on the local humidity. In highly viscous droplets, the evaporation rates of organic components are suppressed to varying degrees, yet water evaporation remains fast. Here, we examine the coevaporation of semivolatile organic compounds (SVOCs), along with their solvating water, from aerosol particles levitated in a humidity-controlled environment. To better replicate the composition of secondary aerosol, nonvolatile organics were also present, creating a three-component diffusion problem. Kinetic modeling reproduced the evaporation accurately when the SVOCs were assumed to obey the Stokes-Einstein relation, and water was not. Crucially, our methodology uses previously collected data to constrain the time-dependent viscosity, as well as water diffusion coefficients, allowing it to be predictive rather than postdictive. Throughout the study, evaporation rates were found to decrease as SVOCs deplete from the particle, suggesting path function type behavior.

Development of lithium attachment mass spectrometry - knudsen effusion and chemical ionisation mass spectrometry (KEMS, CIMS)

Lithium ion attachment mass spectrometry provides a non-specific, non-fragmenting, sensitive and robust method for the detection of volatile species in the gas phase. The design, manufacture and results of lithium based ion attachment ionisation sources for two different mass spectrometry systems are presented. In this study trace gas analysis is investigated using a modified Chemical Ionization Mass Spectrometer (CIMS) and vapour pressure measurements are made using a modified Knudsen Effusion Mass Spectrometer (KEMS). In the Li⁺ CIMS, where the Li⁺ ionization acts a soft and unselective ionization source, limits of detection of 0.2 ppt for formic acid, 15 ppt for nitric acid and 120 ppt for ammonia were achieved, allowing for ambient measurements of such species at atmospherically relevant concentrations. In the first application of Lithium ion attachment in ultra-high vacuum (UHV), vapor pressures of various atmospherically relevant species were measured with the adapted KEMS, giving measured values equivalent to previous results from electron impact KEMS. In the Li⁺ KEMS vapour pressures <10^-3 mbar can be measured without any fragmentation, as is seen with the initial electron impact (EI) set up, allowing the vapor pressure of individual components within mixtures to be determined.

Measured Saturation Vapor Pressures of Phenolic and Nitro-aromatic Compounds

Phenolic and nitro-aromatic compounds are extremely toxic components of atmospheric aerosol that are currently not well understood. In this Article, solid and subcooled-liquid-state saturation vapor pressures of phenolic and nitro-aromatic compounds are measured using Knudsen Effusion Mass Spectrometry (KEMS) over a range of temperatures (298-318 K). Vapor pressure estimation methods, assessed in this study, do not replicate the observed dependency on the relative positions of functional groups. With a few exceptions, the estimates are biased toward predicting saturation vapor pressures that are too high, by 5-6 orders of magnitude in some cases. Basic partitioning theory comparisons indicate that overestimation of vapor pressures in such cases would cause us to expect these compounds to be present in the gas state, whereas measurements in this study suggest these phenolic and nitro-aromatic will partition into the condensed state for a wide range of ambient conditions if absorptive partitioning plays a dominant role. While these techniques might have both structural and parametric uncertainties, the new data presented here should support studies trying to ascertain the role of nitrogen containing organics on aerosol growth and human health impacts.

An assessment of vapour pressure estimation methods

Laboratory measurements of vapour pressures for atmospherically relevant compounds were collated and used to assess the accuracy of vapour pressure estimates generated by seven estimation methods and impacts on predicted secondary organic aerosol. Of the vapour pressure estimation methods that were applicable to all the test set compounds, the Lee-Kesler [Reid et al., The Properties of Gases and Liquids, 1987] method showed the lowest mean absolute error and the Nannoolal et al. [Nannoonal et al., Fluid Phase Equilib., 2008, 269, 117-133] method showed the lowest mean bias error (when both used normal boiling points estimated using the Nannoolal et al. [Nannoolal et al., Fluid Phase Equilib., 2004, 226, 45-63] method). The effect of varying vapour pressure estimation methods on secondary organic aerosol (SOA) mass loading and composition was investigated using an absorptive partitioning equilibrium model. The Myrdal and Yalkowsky [Myrdal and Yalkowsky, Ind. Eng. Chem. Res., 1997, 36, 2494-2499] vapour pressure estimation method using the Nannoolal et al. [Nannoolal et al., Fluid Phase Equilib., 2004, 226, 45-63] normal boiling point gave the most accurate estimation of SOA loading despite not being the most accurate for vapour pressures alone.

Whole grains and health: from theory to practice--highlights of The Grains for Health Foundation's Whole Grains Summit 2012

The Grains for Health Foundation's Whole Grains Summit, held May 19-22, 2012 in Minneapolis, was the first meeting of its kind to convene >300 scientists, educators, food technologists, grain breeders, food manufacturers, marketers, health professionals, and regulators from around the world. Its goals were to identify potential avenues for collaborative efforts and formulate new approaches to whole-grains research and health communications that support global public health and business. This paper summarizes some of the challenges and opportunities that researchers and nutrition educators face in expanding the knowledge base on whole grains and health and in translating and disseminating that knowledge to consumers. The consensus of the summit was that effective, long-term, public-private partnerships are needed to reach across the globe and galvanize the whole-grains community to collaborate effectively in translating whole-grains science into strategies that increase the availability and affordability of more healthful, grain-based food products. A prerequisite of that is the need to build trust among diverse multidisciplinary professionals involved in the growing, producing, marketing, and regulating of whole-grain products and between the grain and public health communities.

Aleurone flour increases red-cell folate and lowers plasma homocyst(e)ine substantially in man

Aleurone flour (ALF) is a rich source of natural folate (>500 μg/100 g wet weight). Our objective was to establish whether intake of ALF in man can significantly improve folate status and reduce plasma homocyst(e)ine. We performed a randomised, controlled intervention, of 16 weeks duration, in free-living healthy individuals (mean age 46–52 years). Participants were assigned to one of three groups: ALF, 175 g bread made with ALF and placebo tablet each day; PCS, 175 g bread made with pericarp seed coat (PCS) flour and placebo tablet each day (low-folate control); or FA, 175 g bread made with PCS flour and tablet containing 640 μg folic acid each day (high-folate control). The daily folate intake contributed by the bread and tablet was 233 μg in the PCS group, 615 μg in the ALF group and 819 μg in the FA group. The number of participants completing all phases of the PCS, ALF and FA interventions was twenty-five, twenty-five and eighteen, respectively. Plasma and red-cell folate increased significantly (P<0·0001) and plasma homocyst(e)ine decreased significantly (P<0·0001) in the ALF and FA groups only. Plasma folate and red-cell folate in the ALF group (mean, 95 % CI) increased from baseline values of 12·9 (9·9, 15·7) nmol/l and 509 (434, 584) nmol/l to 27·1 (22·5, 31·7) nmol/l and 768 (676, 860) nmol/l, respectively. Plasma homocyst(e)ine in the ALF group decreased from 9·1 (8·2, 10·0) μmol/l at baseline to 6·8 (6·2, 7·5) μmol/l after 16 weeks. In conclusion, moderate dietary intake of ALF can increase red-cell folate and decrease plasma homocyst(e)ine substantially.

Consumption of foods by young children with diagnosed campylobacter infection – a pilot case–control study

Objective:

To determine whether parentally reported habitual intake of specific foods differed between children with diagnosedCampylobacter jejuniinfection and children of a comparison group without diagnosed infection.

Design, setting and subjects:

Information was collected from the parents or primary caregivers of South Australian children aged 1–5 years with diagnosedC. jejuni(cases,n=172) and an age- and gender-matched group of uninfected children (controls,n=173). Frequency of consumption of 106 food and drink items was determined for the preceding two months by food-frequency questionnaire. Four children in the control group had recorded diarrhoeal episodes during the assessment period and were excluded, so 169 responses were evaluated for this group. Information was gathered on possible confounders including socio-economic status. Response frequencies were classified into three levels of consumption (rarely, weekly or daily) and statistical comparison was made by frequency of consumption of foods versus the ‘rarely’ classification for cases and controls, respectively.

Results:

Frequency of consumption of most foods, including starchy foods and fruits and vegetables, did not differ between cases and controls. However, reported consumption of eight food items (block and processed cheese (slices and spread), salami/fritz (a form of processed sausage), chicken nuggets, pasteurised milk, fish (canned or fresh) and hot French fries) was significantly higher by controls.

Conclusions:

The hypothesis that reported consumption of starchy foods was lower by cases than by controls was not supported by the data. However, consumption of some processed and unprocessed foods was higher by controls. Some of these foods have established bactericidal actionsin vitrothat may indicate a possible mechanism for this apparent protection.

High-amylose wheat generated by RNA interference improves indices of large-bowel health in rats

Foods high in resistant starch have the potential to improve human health and lower the risk of serious noninfectious diseases. RNA interference was used to down-regulate the two different isoforms of starch-branching enzyme (SBE) II (SBEIIa and SBEIIb) in wheat endosperm to raise its amylose content. Suppression of SBEIIb expression alone had no effect on amylose content; however, suppression of both SBEIIa and SBEIIb expression resulted in starch containing >70% amylose. When the >70% amylose wheat grain was fed to rats in a diet as a wholemeal, several indices of large-bowel function, including short-chain fatty acids, were improved relative to standard wholemeal wheat. These results indicate that this high-amylose wheat has a significant potential to improve human health through its resistant starch content.

Population and virulence factor dynamics in fecalEscherichia colifrom healthy adults consuming weight control diets

Individual susceptibility to gastrointestinal infection is seen commonly in food poisoning outbreaks, but factors (such as diet) which may modulate this variability are understood poorly. Similarly, factors altering the population dynamics of enteric non-pathogenic Escherichia coli or of pathogenic E. coli containing toxin-signature DNA sequences in the colonic flora of healthy individuals are largely unknown. Feces were collected 4 times over a 12 week period from 41 healthy volunteer adults on a weight control diet (high or low in fiber). E. coli strains were examined by conventional culture followed by PCR for virulence genes stx1, stx2, eae and hlyA, and polymorphic β-glucuronidase. Total E. coli counts ranged from undetectable to 8.75 log10CFU/g feces and were unaffected by dietary fiber consumption or gender. Total E. coli counts were correlated positively with age (r = 0.401, P < 0.05). Fifty-eight percent (n = 24) of study individuals harboured more than 1 morph of β-glucuronidase, indicating the presence of more than 1 strain of E. coli. Virulence genes were detected in 12 of 41 adults, comprising 10 stx1, 3 stx2, 3 eae, and 0 hlyA, but occurrence was not associated with diet, gender, or age. Factors influencing strain mobility over time did not appear to include diet or gender, while the positive relationship between total E. coli numbers and increasing age suggests that some older individuals are "more permissive" to mobile E. coli, including those with toxin genes.Key words: Escherichia coli, virulence, healthy humans, diet.

The impact of involvement of biomedical scientists in specimen dissection and selection of blocks for histopathology: a study of time benefits and specimen handling quality in Ayrshire and Arran area laboratory

AIMS

To assess possible time benefits of specimen dissection by biomedical scientists (BMSs) and the quality of specimen handling by BMSs, in a department where BMSs trim those specimens requiring simple descriptions, from which standard blocks are taken.

METHODS

Specimen handling by BMSs and consultant pathologists was compared. Time taken for each specimen trimmed was recorded prospectively. To determine specimen handling quality, adherence to dissection standard operating procedures (SOPs) was assessed by recording retrospectively whether or not each action in the SOP had been performed. Information on subsequently required extra levels or blocks was recorded.

RESULTS

Analysis of data from 672 specimens trimmed by consultants showed that any given action in the SOPs was performed on average on 60.2% of applicable/assessable specimens; for 660 similar specimens trimmed by BMSs, each action was performed on average on 80.1% of specimens. Of the specimens where data on extra blocks were recorded, extra blocks were required in 3% of those trimmed by pathologists and in 4% of those trimmed by BMSs. Extra levels were required in 12% of those trimmed by pathologists and in 16% of those trimmed by BMSs. BMS trimming saves 16 hours of consultant time each month. The difference between pathologists and BMSs in time for each specimen trimmed is negligible.

CONCLUSIONS

The advantages of increased adherence to trimming SOPs and saving consultant time outweigh the relatively small number of extra blocks and levels required when BMSs trim. There is no reduction in quality of dissection.

Insulin stimulation of hepatic triacylglycerol secretion and the etiology of insulin resistance

The recent observations that insulin can either stimulate or inhibit triacylglycerol secretion by the liver, depending on prior metabolic (possibly insulinemic) state, have rationalized the many apparently contradictory observations, obtained over the past three decades, on the effects of the hormone on this aspect of hepatic metabolism. Extrapolation to the situation in vivo suggests that frequent stimulation of insulin secretion may result in a chronic stimulation of VLDL secretion, and increased delivery of acyl moieties to muscle, where they induce insulin resistance if provided in excess of the oxidative needs (mostly due to exercise) of the tissue. High fructose/sucrose diets, which also stimulate hepatic VLDL secretion, will have the same effect, especially if consumed frequently during the diurnal cycle. Due to the quantitative importance of muscle as a site for insulin-sensitive glucose metabolism, these effects may initiate the metabolic vicious cycle that results in the development of the metabolic syndrome, well in advance of overt obesity or the diagnosis of type-2 diabetes.

Modulation of the acute phase response by altered expression of the IL-1 type 1 receptor or IL-1ra

A complete understanding of the role for endogenously produced interleukin-1 (IL-1), tumor necrosis factor-alpha (TNF-alpha), and IL-1 receptor antagonist (IL-1ra) in the acute phase response to inflammation remains unknown. In the present studies, knockout mice lacking either a functional IL-1 type I receptor (IL-1RI(-/-)), a TNF type I receptor (TNFR-I(-/-)), or both IL-1 type I and TNF type I receptors (IL-1RI(-/-)/TNFR-I(-/-)) received a turpentine abscess. Additional mice deficient in IL-1ra protein (IL-1ra(-/-)) or overexpressing IL-1ra protein (IL-1ra(tg)) were similarly treated. After a turpentine abscess, IL-1 receptor knockout mice exhibited an attenuated inflammatory response compared with wild-type or animals lacking a functional TNFR-I. Mice overexpressing IL-1ra also had an attenuated hepatic acute phase protein response, whereas IL-1ra knockout mice had a significantly greater hepatic acute phase response. We conclude that the inflammatory response to a turpentine abscess is the result of a balance between IL-1ra expression and IL-1 binding to its type I receptor. Endogenously produced IL-1ra plays a central role in mitigating the magnitude of the IL-1-mediated inflammatory response and, ultimately, the outcome to a turpentine abscess.

Aleurone flour is a rich source of bioavailable folate in humans

With the use of novel milling technology, it has become commercially viable to isolate the aleurone layer of cells from wheat grain and to prepare a novel flour from this fraction that has a natural folate concentration of approximately 500 microgram/100 g. The aim of this study was to determine the relative bioavailability of natural folate from aleurone flour when ingested as a cereal. Using a series of randomized, short-term intervention trials with a cross-over involving eight men and eight women aged between 29 and 50 y, we compared the increment of plasma folate following ingestion of 1) 100 g wheat bran cereal (low folate control), 2) 100 g aleurone cereal, and 3) a tablet containing 500 microgram folic acid taken together with 100 g wheat bran cereal (high folate control). Folate absorption was measured by estimating the area under the plasma folate concentration versus time curve. The extent of increase in plasma folate over the 7-hour period following ingestion of aleurone cereal was more than fourfold greater than that observed following the wheat bran cereal (P < 0.0001) and not different from that observed following the 500 microgram folic acid tablet taken with wheat bran cereal. Differences were significant when data for males and females were analyzed separately (P < 0.001). This study has shown that cereal made from wheat aleurone flour is a good source of bioavailable, natural folate.

Arginine-enhanced enteral nutrition augments the growth of a nitric oxide-producing tumor

BACKGROUND

Arginine-enhanced diets have been shown to be beneficial in tumor-bearing hosts, but no data exist regarding their effects in hosts bearing nitric oxide (NO)-producting tumors.

OBJECTIVE

To examine the effect of arginine supplementation on the growth of a NO-producing murine breast cancer cell line.

METHODS

EMT-6 cells were grown in various concentrations of arginine in the presence or absence of the inducible nitric oxide synthase (iNOS) inhibitor, aminoguanidine (1 mmol/L). Forty-eight hours later, nitrite accumulation and viable cell number were assessed. BALB/c mice were then pair-fed basal purified diets (n = 10), 4% casein diets (isonitrogenous control, n = 5), or 4% arginine-enhanced diets (n = 10). One week later, 10(5) EMT-6 cells were implanted subcutaneously into the dorsal flank. After tumor implantation, five mice fed basal purified diets and five mice fed arginine-enhanced diets also received aminoguanidine (100 mg/kg subcutaneously twice daily). Two weeks after tumor cell implantation, tumor size (mean diameter), animal weight, serum and tumor nitrite and nitrate levels were measured.

RESULTS

There was minimal nitrite accumulation in arginine-free media, while increasing the arginine concentration increased nitrite levels. Viable cell number did not increase in arginine-free media, but increased nearly twofold in 100 and 1000 mumol/L arginine. In 5000 and 10,000 mumol/L arginine, the difference in viable cell number was not statistically different than that seen in arginine-free media, whereas the addition of aminoguanidine blocked nitrite accumulation and increased viable cell number at these arginine concentrations. Arginine-enhanced diets stimulated tumor growth in vivo more than twofold over tumor growth in mice fed isonitrogenous control or basal purified enteral diets. Mice fed arginine-enhanced diets also had increased serum nitrite and nitrate levels over mice fed basal purified enteral diets, whereas tumors from mice fed arginine-enhanced diets had nitrite and nitrate levels similar to mice fed basal purified enteral diets. Aminoguanidine blocked the increase in serum nitrite and nitrate, but failed to block the increased tumor growth in mice receiving the arginine-supplemented diets.

CONCLUSIONS

Arginine concentration influences the growth of EMT-6 tumor cells in vitro and dietary arginine supplementation augments tumor growth in vivo. The mechanism of the growth modulation in vitro is NO-dependent whereas the enhanced tumor growth in vivo is NO-independent.

Hydroxypropylmethylcellulose, viscosity, and plasma cholesterol control

The mechanism for the lowering of plasma cholesterol by water-soluble nonstarch polysaccharides (NSP) could involve alteration of intestinal viscosity leading to attenuated fat and steroid digestion and absorption. Alternatively, there may be direct inhibition of hepatic cholesterol synthesis by short-chain fatty acids produced by large bowel bacterial fermentation. A synthetic NSP, hydroxypropylmethylcellulose (HPMC), has been shown to lower plasma low-density lipoprotein (LDL) cholesterol in humans. This polysaccharide is not fermented by the large bowel microflora and has been shown to lower the plasma and liver cholesterol in hamsters, with no change noted in hepatic sterol synthesis. In further studies with hamsters, a linear relationship has been identified between plasma cholesterol and the logarithm of hydroxymethylcellulose viscosity. Only a relatively small increment in viscosity was necessary to achieve a maximal effect, suggesting that intestinal digestion may be quite sensitive to increased NSP intake.

Dietary fatty acids and protection against experimental cardiac arrhythmias in rats

Sudden cardiac death accounts for about 50% of total coronary disease mortality in westernized industrial countries. The lack of early symptoms for this disorder makes prevention the preferred strategy. In a rat model of cardiac ischemia, dietary n-6 (sunflower seed oil) and n-3 (fish-oil) polyunsaturated fatty acids were shown to protect against arrhythmia compared with saturated fat, with greatest protection observed with fish oil. The frequency of arrhythmia was similar with monounsaturated fat from olive oil and saturated fat.

Oat bran lowers plasma cholesterol levels in mildly hypercholesterolemic men

The effects of oat bran and wheat bran on plasma lipid concentrations were compared in a crossover study. Each bran (123 g oat bran or 54 g wheat bran) added nearly 18 g of nonstarch polysaccharide to a background diet containing about 10 g nonstarch polysaccharide. Twenty-three men (average plasma cholesterol level = 5.84 mmol/L, and low-density-lipoprotein (LDL) cholesterol level = 4.11 mmol/L) were randomly assigned to either the oat or wheat bran diet for 4 weeks and then changed to the alternate bran diet for a similar period. The oat bran diet produced significantly lower levels of plasma total cholesterol and LDL cholesterol: 5.65 +/- 0.16 and 3.88 +/- 0.15 mmol/L (mean +/- standard error) for oat bran vs 5.89 +/- 0.16 and 4.11 +/- 0.16 mmol/L for wheat bran. Food intake diaries showed that average consumption of total fat and saturated fat was identical during the two test periods, which excluded displacement of fat as an explanation for lowering of plasma cholesterol by oat bran. Our results indicate that in mildly hypercholesterolemic men, a diet high in soluble oat fiber can significantly lower plasma total cholesterol and LDL cholesterol and thus potentially lower the risk of coronary heart disease.

Simplified presumptive tests for carbohydrate-hydrolyzing enzymes

Simply, relatively rapid and inexpensive tests for amylase, sucrase, and lactase were described. These tests were applicable to fresh or frozen intestinal content and tissue samples obtained at necropsy.