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Background: Approximately 70%-100% of the Asian adult population is lactase nonpersistent (LNP). The literature shows that many individuals with the LNP-genotype can consume ≤12 g of lactose without experiencing gastrointestinal discomfort. Repetitive consumption of lactose may reduce intolerance symptoms via adaptation of the gut microbiota., Objective: This study aimed to assess the effects of daily consumption of incremental lactose doses on microbiota composition and function, and intolerance symptoms., Methods: Twenty-five healthy adults of Asian origin, carrying the LNP-genotype were included in this 12-wk before and after intervention trial. Participants consumed gradually increasing lactose doses from 3 to 6 g to 12 g twice daily, each daily dose of 6 g, 12 g, or 24 g being provided for 4 consecutive weeks. Participants handed-in repeated stool samples and underwent a 25 g lactose challenge hydrogen breath test (HBT) before and after the 12-wk intervention. Daily gastrointestinal symptoms and total symptom scores (TSSs) during the lactose challenge were recorded., Results: A significant increase from 5.5% ± 7.6% to 10.4% ± 9.6% was observed in Bifidobacterium relative abundance after the intervention (P = 0.009), accompanied by a 2-fold increase (570 ± 269 U/g; P < 0.001) in fecal β-galactosidase activity compared with baseline (272 ± 158 U/g). A 1.5-fold decrease (incremental area under the curve; P = 0.01) in expired hydrogen was observed during the second HBT (38 ± 35 ppm·min), compared with the baseline HBT (57 ± 38 ppm·min). There was a nonsignificant decrease in TSS (10.6 ± 8.3 before compared with 8.1 ± 7.2 after intervention; P = 0.09). Daily consumption of lactose was well tolerated, with mild to no gastrointestinal complaints reported during the intervention., Conclusions: Increased levels of Bifidobacterium indicate an adaptation of the gut microbiota upon repetitive consumption of incremental doses of lactose, which was well tolerated as demonstrated by reduced expired hydrogen concentrations during the second 25-g lactose HBT. Bifidobacteria metabolize lactose without gas production thereby potentially reducing intestinal gas formation in the gut of individuals with the LNP-genotype. This increased lactose tolerance possibly lifts the necessity to remove nutrient-rich dairy foods completely from the diet. The trial is registered at the International Clinical Trials Registry Platform: NL9516. The effect of dietary lactose in lactase nonpersistent individuals on gut microbiota., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

GM1 gangliosidosis is a neurodegenerative disorder caused by mutations in the GLB1 gene, which encodes lysosomal β-galactosidase. The enzyme deficiency blocks GM1 ganglioside catabolism, leading to accumulation of GM1 ganglioside and asialo-GM1 ganglioside (GA1 glycolipid) in brain. This disease can present in varying degrees of severity, with the level of residual β-galactosidase activity primarily determining the clinical course. Glb1 null mouse models, which completely lack β-galactosidase expression, exhibit a less severe form of the disease than expected from the comparable deficiency in humans, suggesting a potential species difference in the GM1 ganglioside degradation pathway. We hypothesized this difference may involve the sialidase NEU3, which acts on GM1 ganglioside to produce GA1 glycolipid. To test this hypothesis, we generated Glb1/Neu3 double KO (DKO) mice. These mice had a significantly shorter lifespan, increased neurodegeneration, and more severe ataxia than Glb1 KO mice. Glb1/Neu3 DKO mouse brains exhibited an increased GM1 ganglioside to GA1 glycolipid ratio compared with Glb1 KO mice, indicating that NEU3 mediated GM1 ganglioside to GA1 glycolipid conversion in Glb1 KO mice. The expression of genes associated with neuroinflammation and glial responses were enhanced in Glb1/Neu3 DKO mice compared with Glb1 KO mice. Mouse NEU3 more efficiently converted GM1 ganglioside to GA1 glycolipid than human NEU3 did. Our findings highlight NEU3's role in ameliorating the consequences of Glb1 deletion in mice, provide insights into NEU3's differential effects between mice and humans in GM1 gangliosidosis, and offer a potential therapeutic approach for reducing toxic GM1 ganglioside accumulation in GM1 gangliosidosis patients., Competing Interests: Conflict of interest The author declares that they have no conflicts of interest with the contents of this article., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: GM1 gangliosidosis is a rare, fatal, neurodegenerative disease caused by mutations in the GLB1 gene and deficiency in β-galactosidase. Delay of symptom onset and increase in lifespan in a GM1 gangliosidosis cat model after adeno-associated viral (AAV) gene therapy treatment provide the basis for AAV gene therapy trials. The availability of validated biomarkers would greatly improve assessment of therapeutic efficacy., Methods: The liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to screen oligosaccharides as potential biomarkers for GM1 gangliosidosis. The structures of pentasaccharide biomarkers were determined with mass spectrometry, as well as chemical and enzymatic degradations. Comparison of LC-MS/MS data of endogenous and synthetic compounds confirmed the identification. The study samples were analyzed with fully validated LC-MS/MS methods., Findings: We identified two pentasaccharide biomarkers, H3N2a and H3N2b, that were elevated more than 18-fold in patient plasma, cerebrospinal fluid (CSF), and urine. Only H3N2b was detectable in the cat model, and it was negatively correlated with β-galactosidase activity. Following intravenous (IV) AAV9 gene therapy treatment, reduction of H3N2b was observed in central nervous system, urine, plasma, and CSF samples from the cat model and in urine, plasma, and CSF samples from a patient. Reduction of H3N2b accurately reflected normalization of neuropathology in the cat model and improvement of clinical outcomes in the patient., Interpretations: These results demonstrate that H3N2b is a useful pharmacodynamic biomarker to evaluate the efficacy of gene therapy for GM1 gangliosidosis. H3N2b will facilitate the translation of gene therapy from animal models to patients., Funding: This work was supported by grants U01NS114156, R01HD060576, ZIAHG200409, and P30 DK020579 from the National Institutes of Health (NIH) and a grant from National Tay-Sachs and Allied Diseases Association Inc., Competing Interests: Declaration of interests DSO and XJ are named as co-inventors on a patent application pertaining to use of pentasaccharide biomarkers in GM1 gangliosidosis. ALG, DRM, HLG-E and MSE are beneficiaries of a prior licensing agreement with Sio Gene Therapies (New York, New York). DRM and MSE are shareholders in Lysogene (Neuilly-sur-Seine, France)., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)

Objective: Podocyte injury has a critical role in the pathogenesis of diabetic nephropathy (DN). Microencapsulated islet transplantation (MIT) is identified as an effective method for improving the clinical condition of DN. This study aimed to explore the role and mechanism of MIT in alleviating podocyte injury in DN., Methods: A mouse model of DN was constructed using streptozotocin (STZ). Mice were divided into 3 groups: the untreated diabetic nephropathy group (DN group), the microencapsulated islet transplantation-treated group (MIT group) and the control group. The mice were raised for 6 weeks posterior to islet transplantation to identify the role of MIT. Renal function and structure of glomerular filtration barrier were assessed by urine analysis, histopathological examination, and transmission electron microscopy. The expression levels of several proteins including Caspase-3, Bcl2/Bax, β-galactosidase, Ki-67, synaptopodin, WT-1, Jagged-1, Notch-1, and Hes-1 in renal tissues were identified via immunohistochemistry (IHC), immunofluorescence (IF), and western blotting techniques., Results: Compared with the DN group, the MIT group presented decreased levels of blood glucose, urinary albumin/creatinine, urea nitrogen, and serum creatinine while their body weight gradually increased. Glomerular injury in the MIT group was significantly better than that in the DN group. The MIT group indicated significantly decreased expression of Caspase-3, β-galactosidase, Bax/Bcl-2, and Ki-67 when compared with DN group, while the proportion of synaptopodin- and WT-1-positive cells was significantly increased (P < 0.05). The protein expression of Jagged-1, Notch-1, and Hes-1 in the glomerulus of the MIT group was significantly lower than that in the DN group (P < 0.05)., Conclusion: MIT alleviates podocyte injury induced by DN by inhibiting Notch-1 signaling. The identification of signaling pathways influencing podocyte restoration can help evaluate personalized medicine efficacy for patients treated with islet transplantation., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Mutations in the galactosidase β 1 ( GLB1 ) gene cause lysosomal β-galactosidase (β-Gal) deficiency and clinical onset of the neurodegenerative lysosomal storage disease, GM1 gangliosidosis. β-Gal and neuraminidase 1 (NEU1) form a multienzyme complex in lysosomes along with the molecular chaperone, protective protein cathepsin A (PPCA). NEU1 is deficient in the neurodegenerative lysosomal storage disease sialidosis, and its targeting to and stability in lysosomes strictly depend on PPCA. In contrast, β-Gal only partially depends on PPCA, prompting us to investigate the role that β-Gal plays in the multienzyme complex. Here, we demonstrate that β-Gal negatively regulates NEU1 levels in lysosomes by competitively displacing this labile sialidase from PPCA. Chronic cellular uptake of purified recombinant human β-Gal (rhβ-Gal) or chronic lentiviral-mediated GLB1 overexpression in GM1 gangliosidosis patient fibroblasts coincides with profound secondary NEU1 deficiency. A regimen of intermittent enzyme replacement therapy dosing with rhβ-Gal, followed by enzyme withdrawal, is sufficient to augment β-Gal activity levels in GM1 gangliosidosis patient fibroblasts without promoting NEU1 deficiency. In the absence of β-Gal, NEU1 levels are elevated in the GM1 gangliosidosis mouse brain, which are restored to normal levels following weekly intracerebroventricular dosing with rhβ-Gal. Collectively, our results highlight the need to carefully titrate the dose and dosing frequency of β-Gal augmentation therapy for GM1 gangliosidosis. They further suggest that intermittent intracerebroventricular enzyme replacement therapy dosing with rhβ-Gal is a tunable approach that can safely augment β-Gal levels while maintaining NEU1 at physiological levels in the GM1 gangliosidosis brain., Competing Interests: Conflict of interest—The authors declare that they have no conflicts of interest with the contents of this article., (© 2020 Luu et al.)

Characterized by colonic mucosa intraepithelial lymphocytosis, lymphocytic colitis is primarily an entity presented in the middle-aged to elderly patient population. Very few large series of lymphocytic colitis of childhood occurrence are available in the medical literature. Ten cases each of lymphocytic colitis and of colonic lymphocytosis of other diagnosis, all with duodenal disaccharidases analysis data, were collected from the files of our institution. The electronic medical records were reviewed and multiple variables were analyzed. The ten patients with lymphocytic colitis presented with diarrhea. Of these, three had abdominal pain. The age range was 2-18 years. Nearly all patients were Caucasian (90%) and 70% were female. Endoscopically, most had normal appearing colonic mucosa. Significant past medical history, family medical history and associated comorbidities included celiac disease, Down syndrome, juvenile arthritis and other autoimmune diseases. Interestingly, the most revealing observation was that the majority of cases (80%) were associated with lactase deficiency and, for the most part, gastrointestinal symptoms improved simply by treatment with Lactaid or avoidance of dairy products. This association is statistically significant. Our clinicopathological study indicates that the typical pediatric patient is a female Caucasian. A large of portion of the patients had associated lactase deficiency and improved on Lactaid supplement alone., (Copyright © 2014 Elsevier GmbH. All rights reserved.)

Progressive debilitating neurological defects characterize feline G(M1) gangliosidosis, a lysosomal storage disease caused by deficiency of lysosomal β-galactosidase. No effective therapy exists for affected children, who often die before age 5 years. An adeno-associated viral vector carrying the therapeutic gene was injected bilaterally into two brain targets (thalamus and deep cerebellar nuclei) of a feline model of G(M1) gangliosidosis. Gene therapy normalized β-galactosidase activity and storage throughout the brain and spinal cord. The mean survival of 12 treated G(M1) animals was >38 months, compared to 8 months for untreated animals. Seven of the eight treated animals remaining alive demonstrated normalization of disease, with abrogation of many symptoms including gait deficits and postural imbalance. Sustained correction of the G(M1) gangliosidosis disease phenotype after limited intracranial targeting by gene therapy in a large animal model suggests that this approach may be useful for treating the human version of this lysosomal storage disorder.

Introduction: Anderson-Fabry disease (AFD) is a multiorgan X-linked lysosomal storage disease that particularly affects the heart, kidneys, and cerebrovascular system. Current treatment is with enzyme replacement therapy (ERT), using either beta-galactosidase ('Fabrazyme') or alpha-galactosidase ('Replagal'). From June 2009, it was recommended that patients switch to alpha-galactosidase due to a manufacturing shortage of beta-galactosidase. This study assesses the effect of switching to alpha-galactosidase on clinical outcomes in patients with AFD previously treated with beta-galactosidase., Patients and Methods: Ten patients (seven male, three female) with genetically confirmed AFD and at least 48 months continuous data collected during treatment with beta-galactosidase 1 mg/kg every other week, were switched to alpha-galactosidase 0.2 mg/kg every other week for at least 20 months, with prospective clinical evaluations performed every 6 months. Pre-switch data was collected retrospectively from patient charts. Cardiac functional parameters were assessed using magnetic resonance imaging., Results: Results showed that renal function generally remained stable after the switch. Cardiac mass had already decreased significantly (p < 0.05 vs pre-ERT) after introduction of beta-galactosidase and remained unchanged after switching to alpha-galactosidase. Symptoms of pain and health status scores did not deteriorate during alpha-galactosidase therapy. Adverse events were mostly mild and infusion -related., Discussion: In conclusion, switching to alpha-galactosidse was generally well tolerated and associated with stable clinical status and preservation of both renal and cardiac function.

Court-ordered access to high-cost drugs for rare genetic diseases, such as Fabry Disease (alpha-galactosidase-A deficiency), is a growing phenomenon as yet lacking systematic study. An observational, cross-sectional and retrospective study was conducted to characterize the lawsuits related to access to treatment for Fabry Disease by Enzyme Replacement Therapy in the State of Rio Grande do Sul prior to 2007. The study identified 13 lawsuits and 17 plaintiffs, 11 requesting alfa and 6 betagalsidase. The State of RS, the Federal Government, and 5 municipalities figured as defendants, in the form of joinder of parties or otherwise. There were 13 requests for interlocutory relief of which 12 were granted, and 2 sentences were handed down, both favorable. "Risk of death" was alleged by doctors in 4 prescriptions and by lawyers in the 13 lawsuits. The data suggest the lack of discussions combining aspects of medical efficacy and safety, cost-effectiveness, economic impact, and legal and constitutional arguments, which requires a specific policy for rare genetic diseases to standardize access to treatment.

Adult‑type hypolactasia (lactase nonpersistence or lactase deficiency) is the most common enzyme deficiency leading to lactose intolerance and primary lactose malabsorption. Clinical presentation of the condition includes symptoms resulting from bacterial fermentation of undigested lactose in the colon, which gives rise to gas bloat, increased motility, and loose stools. Diagnosis of the disease is based on clinical symptoms, biochemical, functional, histochemical and genetic tests. Treatment includes dietary restrictions, namely, use of low‑lactose milk, in which lactose has been prehydrolyzed, or non‑lactose milk.

The delivery of bioactive proteins to tumors is associated with many difficulties that have impeded clinical translation of these promising therapeutics. Herein we present an approach, including (1) use of magnetically-responsive and MRI-visible nanoparticles as drug carriers, (2) topography-optimized intra-arterial magnetic targeting, (3) MRI-guided subject alignment within the magnetic field, and (4) surface modification of the protein drug with membrane-permeable polyethyleneimine (PEI), to prevail over the obstacles in protein delivery. Applying these methodologies, we demonstrated the delivery of a significant quantity of β-galactosidase selectively into brain tumors of glioma-bearing rats, while limiting the exposure of normal brain regions. Clinical viability of the technologies utilized, and the ability to deliver proteins at high nanomolar-range tumor concentrations, sufficient to completely eradicate a tumor lesion with existing picomolar-potency protein toxins, renders the prospect of enabling protein-based cancer therapy extremely promising., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Background: Peroral β-galactosidase preparations for the management of lactose intolerance need to be administered in large doses (1500 to 6000 U) immediately before or together with a lactose-containing meal., Aim: Therefore, this work aimed at developing an innovative long-acting formulation. For this purpose, biodegradable polymeric microcarriers were functionalized with β-galactosidase and targeted with wheat germ agglutinin (WGA) for bioadhesion and thus prolonged residence time in the small intestine., Methods: Spray-dried poly(D,L-lactide-co-glycolide) (PLGA) particles with 2.78±1.05µm in diameter were functionalized with β-galactosidase from Kluyveromyces lactis and WGA using different types of spacers (polyethyleneimine, hexamethylene diamine, 6-aminocaproic acid) and coupling methods (carbodiimide and glutaraldehyde). The particle-bound enzyme activity was determined, and the bioadhesive characteristics were assessed by interaction with mucin coatings and Caco-2 cell monolayers., Results: Up to 1470 U β-galactosidase per gram PLGA were immobilized. The best results were obtained with hexamethylene diamine as a spacer applying the carbodiimide method. Thereby, a nearly 6-fold increase in enzyme activity was obtained as compared to particles without spacer. Upon targeting with WGA, binding to artificial human intestinal epithelium was increased considerably., Conclusions: For the delivery of β-galactosidase WGA-targeted PLGA microparticles were prepared, which represent promising candidates for a convenient biomimetic treatment regimen of lactose intolerance., (Copyright © 2010 Elsevier B.V. All rights reserved.)

Adverse food reactions are common in the general population. Nevertheless, our knowledge of the structure of food allergens and of the mechanisms involved is poor. In 1995 the European Academy of Allergology and Clinical Immunology suggested a classification based on the causative pathogenic mechanism. According to this classification, non-toxic reactions can be divided into food allergies when they recognize immunological mechanisms and food intolerance when there are no immunological implications. The treatment of food intolerance is avoidance of the particular food. There are specific treatments for some food intolerance (beta-galactosidases for the management of lactose intolerance).

Lactose malabsorption is a very common condition characterized by intestinal lactase deficiency. Primary lactose malabsorption is an inherited deficit present in the majority of the world's population, while secondary bypolactasia can be the consequence of an intestinal disease. The presence of malabsorbed lactose in the colonic lumen may cause gastrointestinal symptoms. This condition is known as lactose intolerance. Lactase non-persistence is the ancestral state, whilst two single nucleotide polymorphisms in the lactase gene have been associated with lactase persistence. These are C/T 13910 and G/A 22018 substitutions. Lactase persistence, this Mendelian dominant trait, only became advantageous after the invention of agriculture, when milk from domesticated animals became available for adults to drink. Lactase persistence is then strongly correlated with the diary history of the population. Diagnosis is assessed clinically by elimination of dietary lactose or, better, by non-invasive tests including hydrogen breath test and genetic test. In patients with lactase non-persistence, treatment should be considered exclusively if intolerance symptoms are present. In the absence of guidelines, the common therapeutic approach tends to exclude milk and dairy products from the diet. However, this strategy may have serious nutritional disadvantages. Several studies have been carried out to find alternative approaches, such as exogenous beta-galactosidase, yogurt and probiotics for their bacterial lactase activity, strategies that can prolong contact time between enzyme and substrate delaying gastrointestinal transit time, and chronic lactose ingestion to enhance colonic adaptation.

The synthesis and biological evaluation of novel prodrugs for use in the antibody directed enzyme prodrug therapy (ADEPT) of cancer based on the cytotoxic antibiotic duocarmycin SA (1) are described. In this approach, we investigated the influence of the sugar moiety of the glycosidic prodrug on the QIC(50) values as well as on the stability and the water solubility. The best result was found for prodrug 22 containing an alpha-mannoside moiety with a QIC(50) value of 4500.

Background: A lactose-free diet is commonly prescribed to subjects with hypolactasia. We tested the effectiveness of a single ingestion of tilactase (a beta-D-galactosidase from Aspergillus oryzae) in adults with hypolactasia, previously assessed by lactose H(2)-breath test., Materials and Methods: After measurement of orocecal transit time (OCTT, by lactulose H(2)-breath test) and lactose H(2)-breath testing plus placebo, a total of 134 subjects were positive to hypolactasia and underwent lactose H(2)-breath testing plus either low (6750 U) or standard (11,250 U) doses of tilactase. The appearance of gastrointestinal symptoms during the tests was monitored., Results: OCTT was longer in malabsorbers (subjects without bloating, abdominal pain and/or diarrhoea, n = 25) than in intolerants (bloating, abdominal pain and/or diarrhoea, n = 109, P < 0.02). Malabsorbers had longer time to H(2) peak (P < 0.03), lower H(2) peak levels (P < 0.002) and smaller integrated H(2) excretion levels (P < 0.005) than intolerants. After tilactase ingestion, integrated H(2) levels were decreased by 75% (low dose) and 87% (standard dose) in malabsorbers, and by 74% (low dose) and 88% (standard dose) in intolerants. In the latter group, total symptom score were decreased by 76% (low dose) and by 88% (standard dose) (P < 0.0001)., Conclusion: A single oral administration of tilactase is highly effective in decreasing symptoms and hydrogen excretion of hypolactasia assessed by lactose H(2)-breath test. If confirmed by long-term observations, ingestion of tilactase might be a better option than exclusion diets in intolerant subjects with hypolactasia.

Functional screening studies revealed that Aspergillus carbonarius ATCC6276 produced extracellular beta-galactosidase activity potentially suited for use as a lactase digestive supplement in the treatment of lactose intolerance. The crude preparation contained two beta-galactosidase activities, beta-gal 1 and beta-gal 2, which were separated by ion-exchange chromatography. Both enzymes were purified to homogeneity by a combination of gel filtration, ion-exchange, chromatofocusing and hydrophobic interaction chromatographies. beta-gal 1 and beta-gal 2 displayed differences in molecular mass (110 kDa versus 120 kDa as judged by SDS PAGE) and in a range of additional physicochemical properties. Km values of 83 and 309 mM, respectively, were recorded using lactose as substrate while temperature optima of 55 degrees C versus 65 degrees C were obtained. Unlike current commercialized supplemental lactases, both of the purified enzymes displayed significant stability when exposed to simulated gastric conditions, with beta-gal 1 in particular retaining 70% residual activity after exposure to pH 2.0 in the presence of pepsin for 2 h. Overall the results indicate that the beta-galactosidases of Aspergillus carbonarius ATCC6276, either individually or in combination, may be suitable for use as a digestive supplement for the alleviation of lactose intolerance.

Background/aims: To optimise vaccination strategies for immunotherapy in the liver, we have generated a line of transgenic mice expressing beta-Galactosidase downstream of the alpha-fetoprotein promoter (AFP/betaGal)., Methods: betaGal expression was documented by qRT-PCR, enzyme activity and immunohistochemistry. betaGal-specific CD8+ T-cell activation in mice immunised with various vectors was measured by interferon-gamma ELISpot., Results: Like AFP, betaGal expression was detected in fetal hepatocytes and disappeared around birth. In adult mice, a CD8+ T-cell response to betaGal was observed after immunisation with betaGal adenovirus or plasmid DNA but not with betaGal protein or after retroviral infection. When betaGal was re-expressed in adult hepatocytes, immunisation with betaGal adenovirus triggered T-cell mediated elimination of betaGal-expressing hepatocytes. However, the response was weaker than in AFP/betaGal animals in which betaGal was only present around birth., Conclusions: In AFP/betaGal mice, betaGal is a fetal liver self-antigen. Interestingly, the basal tolerance to betaGal displayed by these animals is increased during liver re-expression of the self-antigen in adulthood. Adenoviral immunisation allows complete elimination of betaGal-expressing hepatocytes in spite of this increased peripheral tolerance. These results highlight the importance of tolerance against self-antigens and validate the AFP/betaGal mice as a good background to test immunotherapy strategies in hepatocarcinogenesis models.

Selected microbial lactases are used to treat lactose intolerance. A series of experiments were carried out in vitro in order to determine the likely relative suitability of four major commercial lactase products used in this regard. The lactases displayed between 55 and 61% of maximum activity at 37 degrees C and significant activity between pH 3.0 and 6.5. They retained between 0 and 65% of original activities after exposure to full simulated digestive tract conditions for 6 h. All four enzymes proved to be particularly acid sensitive and only two products were enteric coated. The products demonstrated varying ability to hydrolyze lactose under simulated digestive tract conditions. The most effective product hydrolyzed 2.7 g lactose per capsule, suggesting that consumption of several capsules, as opposed to the usually recommended one or two, would be required to hydrolyze the entire 12 g lactose load characteristic of a dairy-based meal. All enzymes were substantially pure and displayed similar kinetic properties and molecular weights. None appeared ideally suited for use in the alleviation of lactose intolerance. The findings may in part explain the variability and often disappointing results previously reported for lactase-based clinical trials and will provide comparative baseline data against which candidate second-generation lactases may be assessed.

Lactose malabsorption is a very common condition characterized by intestinal lactase deficiency. Primary lactose malabsorption is an inherited deficit present in the majority of the world's population, while secondary hypolactasia can be the consequence of an intestinal disease. The presence of malabsorbed lactose in the colonic lumen causes gastrointestinal symptoms. The condition is known as lactose intolerance. In patients with lactase nonpersistence, treatment should be considered exclusively if intolerance symptoms are present. In the absence of guidelines, the common therapeutic approach tends to exclude milk and dairy products from the diet. However, this strategy may have serious nutritional disadvantages. Several studies have been carried out to find alternative approaches, such as exogenous beta-galactosidase, yogurt and probiotics for their bacterial lactase activity, pharmacological and non pharmacological strategies that can prolong contact time between enzyme and substrate delaying gastrointestinal transit time, and chronic lactose ingestion to enhance colonic adaptation. In this review the usefulness of these approaches is discussed and a therapeutic management with a flow chart is proposed.

Intravascular administration of recombinant adenovirus (rAd) in cancer patients has been well tolerated. However, dose-limiting hemodynamic responses associated with suppression of cardiac output have been observed at doses of 7.5 x 10(13) particles. While analysis of hemodynamic responses induced by small-molecule pharmaceuticals is well established, little is known about the cardiovascular effects of rAd. Telemetric cardiovascular (CV) monitoring in mice was utilized to measure hemodynamic events following intravascular rAd administration. Electrocardiogram analysis revealed a block in the SA node 3-4 min postinfusion, resulting in secondary pacemaking initiated at the AV node. This was associated with acute bradycardia, reduced blood pressure, and hypothermia followed by gradual recovery. Adenovirus-primed murine sera with high neutralizing antibody (nAb) titers could inhibit CV responses, whereas human sera with equivalent nAb titers induced by natural infection were, surprisingly, not inhibitory. Interestingly, repeat dosing within 2-4 h of the primary injection resulted in desensitization, resembling tachyphylaxis, for subsequent CV responses. Last, depletion of Kupffer cells prior to rAd infusion precluded induction of CV responses. These inhibitory effects suggest that rAd interactions with certain cells of the reticular endothelial system are associated with induction of CV responses. Significantly, these studies may provide insight into management of acute adverse effects following rAd systemic delivery, enabling a broadening of therapeutic index.

Objective: To evaluate whether lactase-treated preterm feeds enhance weight gain and feeding tolerance in premature infants., Study Design: Prospective, double-blind, randomized, controlled trial involving 130 infants (26-34 weeks postconceptual age). The primary outcome variable was weight gain (g per day). Other outcome measures included gains in length and head circumference, biochemical indexes of nutritional status, feeding intolerance, and incidence of necrotizing enterocolitis., Results: On study day 10, weight gain (mean +/- SEM) of the treatment group was significantly greater (P <.05) than that of the control group (20.4 +/- 1.8 g/day vs 15.5 +/- 1.6 g/day). By study end, no significant difference in weight gain between treatment and control groups was observed. The difference in serum albumin level was significant at study day 14, with a value of 29.3 +/- 0.6 g/L in the treatment group compared with 27.1 +/- 0.4 g/L in the control group (P <.01). There were no significant differences in caloric intakes, length gain, head circumference gain, feeding intolerance, and incidence of necrotizing enterocolitis., Conclusions: Weight gain may be enhanced during the period of low functional lactase activity of prematurity by addition of lactase to preterm feeds. No adverse effects on feeding tolerance resulted from this treatment.

Persons with lactose intolerance are unable to digest significant amounts of lactose because of a genetically inadequate amount of the enzyme lactase. Common symptoms include abdominal pain and bloating, excessive flatus, and watery stool following the ingestion of foods containing lactose. Lactase deficiency is present in up to 15 percent of persons of northern European descent, up to 80 percent of blacks and Latinos, and up to 100 percent of American Indians and Asians. A sizable number of adults believe they are lactose intolerant but do not actually have impaired lactose digestion, and some persons with lactase deficiency can tolerate moderate amounts of ingested lactose. A diagnosis of lactose intolerance can usually be made with a careful history supported by dietary manipulation. If necessary, diagnosis can be confirmed by using a breath hydrogen or lactose tolerance test. Treatment consists primarily of avoiding lactose-containing foods. Lactase enzyme supplements may be helpful. The degree of lactose malabsorption varies greatly among patients with lactose intolerance, but most of them can ingest up to 12 oz of milk daily without symptoms. Lactose-intolerant patients must ensure adequate calcium intake.

We compared two lactase preparations derived from Aspergillus orizae (AOL) and Penicillinase multicolor (PML) for stability in the stomach and overall enzymatic activity in 10 asymptomatic subjects with lactase deficiency. The subjects were given 10,000 FCC units of either AOL or PML 30 min prior to or simultaneously with 300 ml of milk. Gastric juice was withdrawn through a nasogastric tube immediately after and every 15 min for 60 min, and breath was sampled before and every 15 min for 6 h after the milk ingestion. When lactase was given simultaneously with the milk, gastric juice lactase activity and galactose concentration were significantly higher than the control levels. When lactase preparations were given 30 min prior to the milk, neither lactase activity nor galactose was detected in the gastric juice. The pH of the gastric juice was about 6.0 after the milk ingestion. Breath hydrogen did not increase when milk was ingested simultaneously with enzymes, but did increase if enzymes were given 30 min prior to milk ingestion. There were no significant differences in lactase activity, galactose concentration in gastric juice, or breath hydrogen when AOL and PML were compared. In conclusion, with exogenous lactase, digestion of lactose begins in the stomach when pH is raised to 6.0 by the buffering action of milk. Lactase preparations are effective assessed by breath hydrogen analysis in asymptomatic individuals with lactase deficiency if the enzymes are given simultaneously with milk.

Clinical success in tumor vaccination frequently does not reach expectation. Since vaccination protocols are quite variable, we used the murine renal cell carcinoma line RENCA transfected with the lacZ gene (RENCA-beta-gal) to compare the efficacy of two different vaccination strategies or their combination and to elaborate on the underlying mechanisms. BALB/c mice were vaccinated either with naked lacZ DNA or with attenuated Salmonella typhimurium transformed with lacZ DNA or with dendritic cells (DC) loaded with the beta-galactosidase protein or mice were vaccinated with both DNA and protein. Although all regimens led to a prolongation of survival time, oral vaccination with transfected S. typhimurium followed by i.v. transfer of protein-loaded DC provided the optimal schedule. In this setting, >50% of mice remained tumor free after challenge with 10 times the lethal tumor dose of RENCA-beta-gal. As explored in transfer experiments, the superior efficacy of combining DNA and protein vaccination is due to the facts that 1) optimal protection depends on both activated CD4(+) and CD8(+) cells and 2) CD8(+) CTL are most strongly activated by vaccination with transformed Salmonella, whereas vaccination with protein-loaded DC is superior for the activation of Th. The latter induced sustained activation of CTL and recruitment of nonadaptive defense mechanisms. The data demonstrate the strength of DNA vaccination, particularly by the oral route, and provide evidence that a combined treatment with protein-loaded DC can significantly increase the therapeutic efficacy.

Colic, or persistent unexplained crying in infants, is commonly encountered by health professionals. While not harmful to the child, it can place a great deal of stress on the parents and family. The cause of colic has not been definitively identified. Transient lactose intolerance, as a result of inadequate production of the enzyme lactase, is one possibility. Studies have shown a reduced crying time when formula or breast milk is incubated with lactase. Colief Infant Drops consist of lactase in a glycerol and water solution which, when added to formula or breast milk, converts lactose to simple sugars and makes the feed more easily digestible.

A 2-week-old Toggenburg kid was evaluated for persistent diarrhea and poor body condition. The herd had high morbidity and mortality associated with diarrhea in neonatal kids. Lactose intolerance was diagnosed on the basis of results of a lactose tolerance test and glucose absorption test. Clinically normal herdmates were used as control animals. The kid responded to lactase supplementation. Cryptosporidium organisms were detected in feces of several affected kids during episodes of acute diarrhea. Lactose intolerance was presumed to have developed secondary to intestinal cryptosporidiosis.

New modalities of treatment for colorectal cancer are required to support and improve those currently available. One such approach is immunotherapy by transfer of immunostimulatory genes to tumor cells. Here, we report the use of a herpes simplex virus (HSV) vector that is capable of a single round of infection (disabled infectious single-cycle [DISC]-HSV) as a gene transfer vehicle for colorectal cancer. This vector has potential advantages over other vectors for cancer immunotherapy in that it lyses infected tumor cells. Infection with DISC-HSV inhibited tumor cell growth both in vitro and in vivo. In addition, DISC-HSV-mediated cell killing occurs by both apoptotic and necrotic mechanisms. A range of colorectal tumor cell lines could be rapidly transduced with DISC-HSV/lacZ (14-90% in 4 hr). Both tumor prevention and tumor therapy protocols showed clear antitumor effects with DISC-HSV/mGM-CSF. In the prophylactic approach, an infected/irradiated whole cell vaccine protected up to 80% of mice from rechallenge. In addition, intratumoral injection of established tumors with DISC-HSV/GM-CSF caused rejection in 40% of mice and generated some protection from subsequent rechallenge. In both cases, however, it is clear that a dominant therapeutic effect of the DISC-HSV vector derives from its oncolytic properties, irrespective of the transduced gene. As a prelude to taking these studies forward to human clinical trials, we demonstrate that tumor cells could be successfully grown from freshly obtained human colorectal cancer resections (within 1 week of surgery), were transduced with DISC-HSV/hGM-CSF, and secreted the cytokine. This study provides the preclinical basis for trials of immunotherapy of colorectal cancer using DISC-HSV.

The objective of this study was to evaluate the effects of lactase on lactose malabsorption and its intolerance symptoms, as well as the available way to improve lactose absorption. Healthy adults with a history of lactose intolerance were screened by 25 g lactose tolerance test. The individuals with higher H2 expired and/or lactose intolerance symptoms were selected as the subjects. Subjects were challenged twice with "400 ml low fat milk" and "400 ml low fat milk + 9000Fcc lactase" separately in 3 days interval. The breath H2 concentration and intolerance symptoms were tested in 4 hours after the challenge. The results showed that exogenous lactase can significantly decrease the incidence of lactose malabsorption (the abnormal expiration of H2 decreased from 100% to 48.9%) and milk intolerance symptoms(from 51.1% to 13.3%). The results from this study demonstrate that lactose malabsorption and intolerance symptoms are resulted from the reduced enzyme activities of individuals, and the exogenous lactase can improve lactose absorption and intolerance symptoms. Lactose supplementation may be an available way to increase the dairy consumption and promote health of people.

Background: The relationship between symptoms, intestinal mucosal histology, and disaccharidase activities is not well defined. An analysis of disaccharidase activities was performed in children grouped by age, symptoms, and intestinal mucosal histology and normal values established., Methods: Disaccharidase activities and histology of 246 endoscopically obtained duodenal biopsies in 232 patients (121 girls; age range, 0.08-17 years; mean, 5.9 years) in a 3-year period were reviewed. Patients were divided into two groups based on absence (group 1; n = 142) or presence (group 2; n = 90) of diarrhea and were subdivided by age into, less than 24 months of age and 24 months of age or more. Histologic changes within groups were classified as (A) normal, (B) mild, or (C) moderate to severe based on villus height abnormalities. A questionnaire was sent to 34 patients with hypolactasia to assess the efficacy of lactose avoidance and/or lactase supplementation., Results: All group 1 patients had normal findings in analysis of mucosal specimens, and their disaccharidase activities showed normal values because they had no diarrhea. The geometric means (95% confidence interval) in children aged less than 24 months are (in micromoles of substrate hydrolyzed per minute at 37 degrees C per gram protein) (units [U]) lactase, 36.7 (13.4-100.4); maltase, 178.5 (88.9-356.3); palatinase, 12.7 (3.8-41.5); and sucrase 60.0 (24.0-148.1). In children 24 months of age or more, the values are 23.2 (3.9-108.1), 167.6 (78.8-355.9), 12.7 (4.9-32.9), and 51.0 (20.5-126.0), respectively. Only lactase activity decreased with age (p < 0.05). No differences in disaccharidase activities were noted in patients with and without diarrhea if the mucosal histology was normal (group 1A vs. 2A). In patients with diarrhea, values were commensurate with the degree of mucosal injury, especially in the older group. Twenty-two of 27 patients (81%) who responded to the questionnaire had benefited from lactase supplementation and/or lactose avoidance., Conclusions: We have established normal values for disaccharidase activities in the pediatric population. Although the disaccharidase activities correlate more with degree of intestinal mucosal injury than with symptoms, their activities are difficult to predict accurately based on these criteria. If required, disaccharidase activities should be measured biochemically.

Diagnoses of Clostridium difficile enterocolitis and lactose intolerance were made in a neonatal foal with persistent diarrhea. It was determined that the foal had lactose intolerance on the basis of the results of a lactose tolerance test, and a diagnosis of C difficile enterocolitis was subsequently made. The foal responded to oral administration of metronidazole and lactase. Lactose intolerance is a secondary problem most commonly associated with rotavirus infection, but it can be caused by any condition affecting the small intestine. Because C difficile can affect the small intestine in foals, it was presumably the cause of the lactose intolerance in this foal with persistent diarrhea. Oral administration of lactase was not initially successful in this foal, most likely because of ongoing C difficile enterocolitis. Presumably, metronidazole was an effective treatment for C difficile enterocolitis and administration of lactase allowed for normal digestion of milk until endogenous lactose production returned. Clostridium difficile enterocolitis and lactose intolerance should be considered as differential diagnoses in neonatal foals with diarrhea, especially when the foal is bright and alert.

Lactose intolerance is widespread, with adult-type hypolactasia being the predominant cause of lactose malabsorption. Daily ingestion of less than 240 mL of milk is well tolerated by most lactose-intolerant adults. Some persons with normal lactase activity may become symptomatic on consumption of products containing lactose. Lactose maldigestion may coexist in adults with irritable bowel syndrome and in children with recurrent abdominal pain. Management consists primarily of dietary changes. People who avoid dairy products should receive calcium supplementation and should be advised to read ingredient labels carefully. Several lactase replacement products are available, but their efficacy varies.

The effectiveness of a new beta-D-galactosidase pellet formulation in the treatment of lactose intolerance was studied. The encapsuled beta-D-galactosidase (lactase) pellets were first tested in vitro for their enzymatic activity within an environment simulating gastric conditions and subsequently within an environment simulating duodenal conditions. Effectiveness was measured by the % of glucose formed by hydrolysis of lactose. The pellets were found to retain their enzymatic activity in gastric pH conditions (mean 69 +/- 1 mg/dl glucose) and were found to hydrolyse lactose in human duodenal fluid (106.35 +/- 1 mg/dl). Finally the effectiveness of the new lactase formulation on glucose absorption was studied in 8 lactose intolerant subjects in a randomized, double blind, crossover trial. After fasting, the subjects were given one capsule containing 100 u/ml beta-galactosidase (i.e. 10 pellets of 10 u/ml each) or one capsule containing placebo pellets, followed by 100 g lactose dissolved in water. The washout period between lactose challenges was one week. Plasma glucose concentrations were measured before and at intervals after the challenges and the subjects completed symptom questionnaires every eight hours for 24 hours. Results showed a statistically significant increase in plasma glucose levels 30, 60, 90 and 120 min after lactose ingestion (repeated measures analysis of variance, p<0.01). Subjective ratings of the severity of abdominal cramping, belching, flatulence, vomiting and diarrhoea were significantly decreased following ingestion of the lactase pellets and lactose (no incidence of diarrhoea) compared with after ingestion of placebo and lactose. The results of the study were considered to be very promising as the beta-D-galactosidase formulation (which was produced at very low cost and with great ease) resisted inactivation in the stomach, effectively transformed lactose to glucose in vivo and reduced symptoms of lactose intolerance.

The paper presents the results of clinical and laboratory studies of lactrase, a drug containing lactase. This agent is recommended for splitting lactic sugar in subjects with appreciably decreased production of endogenous lactase (hypolactasia). Twenty-eight patients with this condition were examined. Manifest clinical symptoms of the condition were observed after loading with 50 g of lactose in all examinees. Addition of 250 mg of lactrase to lactose led to complete clinical compensation of the deficit of endogenous lactase in 75% examinees, and if 500 mg of lactrase was administered, hypolactasia was compensated in virtually all patients. A single intake of 50 g of lactose with lactrase causes a statistically reliable increase of glycemia in such patients. Moreover, a reliable effect of lactrase was observed when measuring galactose in the urine following the lactose test with 250 and 500 mg of lactrase. Our results indicate a high efficacy of lactrase in the treatment of patients with hypolactasia.

Some tumor cells express Ags that are potentially recognizable by T lymphocytes and yet do not elicit significant immune responses. To explore new immunotherapeutic strategies aimed at enhancing the recognition of these tumor-associated Ags (TAA), we developed an experimental mouse model consisting of a lethal clone of the BALB/c tumor line CT26 designated CT26.WT, which was transduced with the lacZ gene encoding beta-galactosidase, to create CT26.CL25. The growth rate and lethality of CT26.CL25 and CT26.WT were virtually identical despite the expression by CT26.CL25 of the model tumor Ag in vivo. A recombinant fowlpox virus (rFPV), which is replication incompetent in mammalian cells, was constructed that expressed the model TAA, beta-galactosidase, under the influence of the 40-kDa vaccinia virus early/late promoter. This recombinant, FPV.bg40k, functioned effectively in vivo as an immunogen, eliciting CD8+ T cells that could effectively lyse CT26.CL25 in vitro. FPV.bg40k protected mice from both subcutaneous and intravenous tumor challenge by CT26.CL25, and most surprisingly, mice bearing established 3-day pulmonary metastasis were found to have significant, Ag-specific decreases in tumor burden and prolonged survival after treatment with the rFPV. These observations constitute the first reported use of rFPV in the prevention and treatment of an experimental cancer and suggest that changing the context in which the immune system encounters a TAA can significantly and therapeutically alter the host immune response against cancer.

The term lactase deficiency is widely used to indicate a low or absent level of lactase enzyme in the small intestine, leading to lactose intolerance. This term is correctly used when the intestinal mucosa is damaged and results in secondary lactase deficiency. In the case of the genetically determined decrease of lactase activity during childhood, however, low lactase levels suggest that the majority of the world's population is "abnormal," whereas individuals from caucasian extraction with high levels of lactase enzyme throughout life are then considered "normal." It would be better to ascribe racial and ethnic lactose malabsorption as the result of genetically determined reduction of lactase activity, rather then implying an "abnormality" by the term, "deficiency." Recent studies reveal that this genetic control is at the transcriptional level. The symptomatology of lactose intolerance varies widely, and the diagnostic method of choice is the lactose breath hydrogen test in combination with clinical findings, although small intestinal biopsies should be performed when mucosal diseases are suspected. Treatment of lactose intolerance depends on the age of the child. In young infants complete restriction of lactose containing foods is rarely necessary.

Objective: To compare the efficacy of three commercially available oral lactase preparations in adults with lactose intolerance., Methods: Design--Prospective, randomized, placebo-controlled trial. Setting--Outpatient study in a General Clinical Research Center. Subjects--Ten lactose-intolerant healthy volunteers were challenged with ice cream containing 18 g of lactose. Lactase or placebo was given immediately prior to challenge. Measurements--Symptoms and breath hydrogen excretion were recorded for 3 h following lactose challenge., Results: The three products differed in their abilities to influence symptoms and breath hydrogen excretion. Only Lactaid reduced the breath hydrogen excretion with lactose (mean peak, area under the curve and cumulative breath hydrogen excretion) (p < 0.05). Lactrase and Dairy Ease influenced symptoms: Lactrase reduced pain, bloating and total symptomatic scores (p < 0.05), whereas Dairy Ease only reduced pain (p < 0.05). Lactaid administration did not reduce symptoms., Conclusion: In lactose-intolerant subjects, the available lactase preparations differ in their ability to improve both breath hydrogen excretion and symptoms. Lactrase may be the product of choice for achieving symptomatic improvement.

5'-O-beta-D-galactosyl-5-fluorouridine is a prodrug that can be converted by the enzyme beta-D-galactosidase to the potent antineoplastic drug 5-fluorouridine. The prodrug is more than 100x less toxic than the drug to bone marrow cells in Balb/c mice. The ratio of the IC50 of the prodrug to that of the drug determined on a variety of tumor cell lines in vitro ranged from 500:1-1000:1. An antibody-enzyme conjugate (AEC) was synthesized and purified. Maleimide-substituted COL-1 anti-CEA monoclonal antibody was linked to free thiol groups of beta-D-galactosidase. The conjugate was purified by size exclusion and ion exchange chromatography. It retained full immunoreactivity and enzyme activity. After binding to antigen-positive tumor cells, the conjugate was able to activate the prodrug and specifically kill the cells. We are continuing to investigate this model for its potential use in antibody-directed enzyme prodrug therapy (ADEPT).

Microbial-derived beta-galactosidase (beta-gal) enzyme preparations improve in vivo lactose digestion and tolerance through enhanced gastrointestinal digestion of lactose. Three different beta-gal preparations, Lactogest (soft gel capsule), Lactaid (caplet), and DairyEase (chewable tablet) and placebo were fed to lactose maldigesters with either 20 g or 50 g of lactose to compare the efficacy of these products and to further establish a dose-response relationship for use. All enzyme preparations dramatically reduced both the peak and total breath hydrogen production when fed with milk containing 20 g of lactose. Four capsules of Lactogest, two caplets of Lactaid, or two tablets of DairyEase (each treatment containing approx 6000 IU) reduced total hydrogen production significantly (P < 0.05) below that observed with two capsules of Lactogest (containing approx 3000 IU) in a stoichiometric manner. Symptoms were significantly (P < 0.05) less severe with all the beta-gal products. In contrast, with 50 g of lactose in water, peak and total hydrogen production was modestly, but not significantly reduced by the enzyme treatment. Furthermore, symptom scores for bloating, cramping, nausea, pain, diarrhea, and flatus were not different between treatments and the control. The 50-g lactose dose appeared to overwhelm the ability of either 3000 or 6000 IU of beta-gal to assist significantly with lactose digestion. Results from these studies demonstrate the relative equivalency of chewable, caplet, and soft-gel beta-gal products, based on IUs of enzyme fed.

The effect of a single dose or oral lactase on symptoms, breath hydrogen concentration, and glucose absorption in lactose-intolerant subjects challenged with lactose was studied. Volunteers underwent a lactose challenge test; those whose breath hydrogen concentrations increased 20 ppm or more and who met other criteria were admitted as subjects. After fasting, the subjects were given three chewable lactase tablets (total lactase dose, 9900 FCC units) or placebo tablets in a randomized, double-blind, crossover manner. The subjects also consumed 8 oz of whole milk in which 37.5 g of lactose powder was dissolved (total lactose content, 50 g). The washout period between lactose challenges was at least one week. Breath hydrogen and plasma glucose concentrations were measured before and at intervals after the challenges, and the subjects completed symptom-evaluation questionnaires every eight hours for four days. Twenty-four subjects completed the study. The maximum mean breath hydrogen concentration was significantly lower after lactase treatment than after placebo treatment. In 21 subjects, the area under the hydrogen concentration-time curve (AUC) was lower after lactase than after placebo; three subjects had hydrogen AUCs more than 300 ppm.hr lower. There were no significant differences in plasma glucose levels. Subjective ratings of the severity of abdominal cramping, belching, flatulence, and diarrhea were lower during the first eight hours after challenge in lactase-treated subjects; ratings for bloating were lower during the next eight hours. Single doses of a chewable lactase tablet reduced the concentration of expired hydrogen and symptoms of lactose intolerance after a lactose challenge.

An assessment was made of the efficacy of a beta-galactosidase, obtained from Aspergillus niger and added to intact milk, in decreasing lactose malabsorption and intolerance. Sixteen adult patients with malabsorption and intolerance to this sugar were studied in a double-blind crossover study vs. placebo. A 5-hour hydrogen breath test was used to assess malabsorption of lactose contained in 400 ml milk. When compared with placebo, the addition of exogenous lactase to intact milk caused a statistically significant reduction in the maximum breath H2 concentration (P less than 0.01) and in the cumulative H2 excretion (P less than 0.005). In the same way, the cumulative index for gastrointestinal intolerance was significantly lower (P less than 0.005) after the ingestion of lactase-added milk. This study demonstrates that enzyme replacement therapy, with beta-galactosidases obtained from Aspergillus niger, is effective in decreasing lactose malabsorption and its consequent intolerance in adult subjects with lactase deficiency.

During the past several years there have been many reports of alternative dietary therapies for primary and secondary lactose intolerance. We have learned that it is useful to feed through most episodes of mild diarrhea that previously would have been treated with clear liquid diets. Infant formulas, including both soy-protein and hydrolysate formulas with specially designed carbohydrate, protein, and fat components, are available to treat the infant with diarrheal syndromes and secondary lactase deficiency. Also, the diet can be supplemented with lactase. Specialized lactose-reduced products as well as cultured and fermented dairy products may be used in varying degrees for lactose-intolerant children. The ingestion of milk with food and fiber components in the diet has also been shown to improve symptoms of lactose intolerance. This review summarizes the essentials of diagnosis of and dietary therapy for lactose intolerance. Our findings indicate that a number of specialized formulas and products are available for successful dietary management of lactose intolerance in infants and children.

Lactose-intolerant children manifest diminished or nonexistent intestinal lactase activity, resulting in flatulence, abdominal pain, and diarrhea. To assess the hydrolytic capability of lactase-containing tablets taken immediately before oral lactose challenge, we studied 18 children previously identified as being lactose intolerant and having no underlying organic gastrointestinal disease. Subjects had a mean (+/- SEM) age of 11.4 +/- 3.4 years; 72% were male. At time of the study, lactase-containing tablets or placebo tablets were ingested (double-blind) immediately before drinking a solution of lactose. Breath samples were obtained for hydrogen analysis at 30-minute intervals during a 2-hour period, and clinical symptoms were monitored. In lactose-intolerant patients, hydrogen production was significantly greater following placebo (maximum hydrogen excretion, approximately 60 ppm) compared with lactase-containing tablets (maximum hydrogen excretion, 7 ppm). Increased hydrogen production was associated with clinical symptoms including abdominal pain (89% of subjects following placebo ingestion), bloating (83%), diarrhea (61%), and flatulence (44%). These results indicate, therefore, that coingestion of lactose and lactase-containing tablets significantly reduces both breath hydrogen excretion and clinical symptoms associated with lactose intolerance.