The role of small intestinal bacterial overgrowth and false positive diagnosis of lactose intolerance in southwest Hungary-A retrospective observational study

Background

Lactose intolerance is a frequent gastrointestinal disease affecting 47% of the Eastern European population. Small intestinal bacterial overgrowth (SIBO) leads to carbohydrate malabsorption and therefore to false results during lactose breath and tolerance tests.

Objectives

We aimed to assess the prevalence of lactose maldigestion and intolerance in Hungary and to investigate the role of combined diagnostic method and testing for SIBO in reducing false results.

Methods

We retrospectively analyzed data from 264 adult symptomatic patients who underwent 50g lactose breath and tolerance tests in parallel over a one-year period at our center. A ≥20 ppm elevation of H₂ or less than 1.1 mmol/l rise of blood glucose was diagnostic for lactose maldigestion. Patients with maldigestion who had symptoms during the test were defined as lactose intolerant. Patients with an early (≤90 min) significant (≥20 ppm) rise of H₂ during lactose and/or lactulose breath tests were determined to have SIBO. Patients with slow/rapid oro-cecal transit and inappropriate preparation before the test were excluded.

Results

49.6% of the 264 patients had lactose maldigestion, and 29.5% had lactose intolerance. The most frequent symptom was bloating (22.7%), while 34.8% of the study population and 60% of the symptomatic patients had SIBO. In 9.1% and 9.8% of the patients, the lactose breath and tolerance test alone gave false positive result compared with the combined method. SIBO was present in 75% of the false positives diagnosed with breath test only.

Conclusions

The prevalence of lactose intolerance is lower in Hungary compared to the Eastern European value (29.5% vs 47%), so it is worth performing a population-based prospective analysis in this area. A combination of lactose breath and tolerance tests and the careful monitoring of results (with early H2 rise, lactulose breath test, etc.) can decrease the false cases caused by e.g. SIBO.

Association between increased plasma levels of homocysteine and depression observed in individuals with primary lactose malabsorption

Background

Current literature proposes associations between homocysteine (HCY), folic acid (FA), vitamin B12 metabolism and depression. However, the exact underlying biological mechanisms remain unclear. This study aimed at evaluating a possible link between primary adult-type lactose malabsorption (PALM), HCY, FA and vitamin B12 metabolism and depressive disorder.

Methods

Plasma levels of HCY, FA and vitamin B12 were determined in 78 patients with PALM and 160 individuals with lactase persistence sub-grouped by the presence or absence of major depression.

Results

In 78 patients with PALM, the subgroup of 22 individuals with major depression showed significantly higher median (interquartile range) HCY (10.10 [8.46–12.03] vs. 8.9 [7.54–9.86] μmol/L, p = 0.029) and lower plasma FA levels (5.7 [4.68–9.14] vs. 6.95 [5.24–10.56] μmol/L, p = 0.272) compared to the subgroup of 56 individuals without depression, respectively. No such associations could be observed for those 160 individuals without PALM (i.e., lactase persistence)

Plasma HCY levels were positively correlated with depressive symptoms (p = 0.052), and showed negative correlations with FA (p = < 0.001) and vitamin B12 (p = 0.029), respectively.

Conclusion

Depressed individuals with PALM were found with significantly higher HCY and lower FA levels compared to non-depressed individuals with PALM, however, this association was absent in the subgroup of lactase persistent individuals. These findings suggest an association between increased HCY levels, lactose malabsorption and depression.

The Relationship Between the Human Genome and Microbiome Comes into View

The body's microbiome, composed of microbial cells that number in the trillions, is involved in human health and disease in ways that are just starting to emerge. The microbiome is assembled at birth, develops with its host, and is greatly influenced by environmental factors such as diet and other exposures. Recently, a role for human genetic variation has emerged as also influential in accounting for interpersonal differences in microbiomes. Thus, human genes may influence health directly or by promoting a beneficial microbiome. Studies of the heritability of gut microbiotas reveal a subset of microbes whose abundances are partly genetically determined by the host. However, the use of genome-wide association studies (GWASs) to identify human genetic variants associated with microbiome phenotypes has proven challenging. Studies to date are small by GWAS standards, and cross-study comparisons are hampered by differences in analytical approaches. Nevertheless, associations between microbes or microbial genes and human genes have emerged that are consistent between human populations. Most notably, higher levels of beneficial gut bacteria called Bifidobacteria are associated with the human lactase nonpersister genotype, which typically confers lactose intolerance, in several different human populations. It is time for the microbiome to be incorporated into studies that quantify interactions among genotype, environment, and the microbiome in order to predict human disease susceptibility.

Effects of exogenous lactase administration on hydrogen breath excretion and intestinal symptoms in patients presenting lactose malabsorption and intolerance

OBJECTIVE

To establish whether supplementation with a standard oral dose of Beta-Galactosidase affects hydrogen breath excretion in patients presenting with lactose malabsorption.

METHODS

Ninety-six consecutive patients positive to H2 Lactose Breath Test were enrolled. Mean peak H2 levels, the time to reach the peak H2, the time to reach the cut-off value of 20 ppm, the cumulative breath H2 excretion, the areas under the curve, and a Visual Analogical 10-point Scale for symptoms were calculated. Genotyping of the C/T-13910 variant was carried out.

RESULTS

Following the oral administration of Beta-Galactosidase, in 21.88% of the cases, H2 Lactose Breath Test became negative (Group A), while mean peak H2 levels (74.95 ppm versus 7.85), P < 0.0000, in 17.71% (Group B) were still positive, with the H2 level 20 ppm above the baseline, but the peak H2 levels were significantly lower than those observed at the baseline test (186.7 ppm versus 66.64), P < 0.0000, while in 60.41% (Group C) they were still positive with the peak H2 levels similar to those observed at the baseline test (94.43 versus 81.60 ppm). All 96 individuals tested presented the C/C-13910 genotype nonpersistence.

CONCLUSIONS

The response to oral administration of Beta-Galactosidase in patients with symptoms of lactose malabsorption presents a significant variability.

A biopsy-based quick test in the diagnosis of duodenal hypolactasia in upper gastrointestinal endoscopy

BACKGROUND AND STUDY AIMS

The usefulness of a new quick test for endoscopic diagnosis of adult-type hypolactasia was tested in duodenal biopsies. In this test, an endoscopic biopsy from the postbulbar duodenum is incubated with lactose on a test plate, and a color reaction develops within 20 min as a result of hydrolyzed lactose (a positive result) in patients with normolactasia, whereas no reaction (a negative result) develops in patients with severe hypolactasia.

PATIENTS AND METHODS

Two postbulbar duodenal biopsies were taken from 80 prospectively enrolled adult outpatients with dyspepsia. The biopsies were used for the Quick Lactase Test (Biohit PLC, Helsinki, Finland) and in biochemical disaccharidase (lactase, sucrase, and maltase) assays. In addition, the C/T (-13,910) genotype was determined from DNA extracted from gastric antral biopsies using polymerase chain reaction sequencing in genomic analysis of adult-type hypolactasia.

RESULTS

Twenty-one of 22 patients (95 %; 95 % CI, 87 - 100 %) with biochemical lactase activity < 10 U/g protein, but none of the 58 patients with lactase activity of 10 U/g protein or more had a negative result in the Quick Lactase Test. Seven of the 80 patients (9 %; 95 % CI, 3 - 15 %) had a Quick Lactase Test result that indicated mild hypolactasia (a mild color reaction). All patients with celiac disease (n = 6) had a negative Quick Lactase Test result. Nine of 74 patients (six patients with celiac disease were excluded) had a CC (-13,910) genotype in genomic testing, indicating adult-type hypolactasia. All of them had negative test results with the Quick Lactase Test. Twenty-six patients had a TT genotype, indicating normolactasia, and none of these patients had a negative test result in the Quick Lactase Test. Six of 39 patients (15 %; 95 % CI, 4 - 27 %) with a CT genotype had a negative result in the Quick Lactase Test.

CONCLUSIONS

The Quick Lactase Test effectively identifies patients with severe duodenal hypolactasia. In comparison with CC (adult-type hypolactasia) and TT individuals (normolactasia), the sensitivity and specificity of the Quick Lactase Test result was 100 %. In comparison with biochemical lactase assays, the sensitivity and specificity of a negative Quick Lactase Test for indicating hypolactasia (lactase activity < 10 U/g protein) were 95 % (95 % CI, 87 - 100 %) and 100 %, respectively.

The molecular basis of lactose intolerance

A staggering 4000 million people cannot digest lactose, the sugar in milk, properly. All mammals, apart from white Northern Europeans and few tribes in Africa and Asia, lose most of their lactase, the enzyme that cleaves lactose into galactose and glucose, after weaning. Lactose intolerance causes gut and a range of systemic symptoms, though the threshold to lactose varies considerably between ethnic groups and individuals within a group. The molecular basis of inherited hypolactasia has yet to be identified, though two polymorphisms in the introns of a helicase upstream from the lactase gene correlate closely with hypolactasia, and thus lactose intolerance. The symptoms of lactose intolerance are caused by gases and toxins produced by anaerobic bacteria in the large intestine. Bacterial toxins may play a key role in several other diseases, such as diabetes, rheumatoid arthritis, multiple sclerosis and some cancers. The problem of lactose intolerance has been exacerbated because of the addition of products containing lactose to various foods and drinks without being on the label. Lactose intolerance fits exactly the illness that Charles Darwin suffered from for over 40 years, and yet was never diagnosed. Darwin missed something else--the key to our own evolution--the Rubicon some 300 million years ago that produced lactose and lactase in sufficient amounts to be susceptible to natural selection.

[Clinical and diagnostic importance of the evaluation of the Ig proteases activity in children with intestinal dysbacteriosis]

The specific activity of serine, metal dependent and thiolic Ig proteases in the coprofiltrates of children with manifestations of intestinal dysbacteriosis was determined by the enzyme immunoassay. 56 children with pronounced symptoms of intestinal disorders (37 children aged up to 1 year and 19 children over 1 year) were examined. A group of 25 clinically healthy children was used as control. Simultaneously with protease activity of coprofiltrates, there was detected the level of Ig-degrading activity of the opportunistic bacteria islolates of different taxonomic groups from feces of children with dysbacteriosis of different severity (as determined by the classical bacteriological method). The evaluation of the Ig-proteolytic activity of fecal supernatants, associated with the presence of serine, metal-dependent and thiolic proteases in the intestine, as well as detection of such proteases in microbial isolates, seems to be highly important for the diagnosis of intestinal disorders in children and is recommended for screening of intestinal dysbacteriosis.

The role of colonic microbiota in lactose intolerance

In a previous study we observed a clear difference in lactose intolerance symptoms after a 25-g lactose load in two groups of persons with lactase nonpersistence and similar small intestinal lactase activity. From this observation we hypothesized a colon resistance factor. To identify this factor, the microbial composition of fecal samples of the two lactose intolerant groups (one with mild symptoms, n = 16, and one with diarrhea-predominant symptoms, n = 11) was compared using the fluorescent in situ hybridization technique. Large interindividual differences were found in the numbers of total bacteria and main groups of bacteria (CV: 0.65 and 0.64-0.82 respectively). The bacterial numbers were not significantly different between the two groups. A significant negative correlation, however, was found between the individual symptom scores of the intolerant persons and the numbers of total hybridizable bacteria (r(s) = -0.42, P = 0.03). The results suggest that an increased number of bacteria might contribute--by means of a higher fermentative capacity--to the reduction of lactose intolerance symptoms.

Quantitation of colonic luminal synthesis of butyric acid in piglets

OBJECTIVES

Butyric acid, synthesized via bacterial fermentation in colonic lumen, may play an important role in the nutrition of the colonic mucosa. Since disaccharides, especially lactose, are the principal dietary carbohydrates during infancy, it is important to determine if their fermentation is associated with butyric acid synthesis. The objective of this paper is to describe a newly developed stable isotope method for quantifying butyric acid synthesis in the colonic lumen and to demonstrate its application during cecal infusions of lactose and lactulose in piglets.

METHODS

Nine piglets aged 21 to 30 days were studied during acute anesthesia. The C enrichment of butyric acid was monitored in the portal vein before and during a 120 minutes cecal infusion of [1- C]-butyric acid and either unlabeled lactose (N = 4) or lactulose (N = 5).

RESULTS

The luminal synthesis of BA (micromol x kg x min ) (Mean +/- S.D.) was respectively 1.5 +/- 0.9 and 1.2 +/- 0.6 during lactulose and lactose infusion.

CONCLUSIONS

This study provides new quantitative data on in vivo butyric acid production in the mammalian colon.

Lactose intolerance and intestinal villi morphology in Thai people

OBJECTIVE

To study the relationship of lactose intolerance and intestinal villi morphology in Thai people.

MATERIAL AND METHOD

Subjects for this study were patients with functional dyspepsia who had no history of milk allergy and underwent gastroduodenoscopy. Two mucosal biopsy specimens were taken from beyond the distal end of the second part of the duodenum. The specimens were carefully orientated and were graded according to the following scheme: group I: finger shaped villi; group II: mixed finger and leaf shaped villi; group III: clubbing or blunting shaped villi. All subjects were tested for lactose malabsorption by breath hydrogen analysis after consuming 50 gram lactose. Breath hydrogen concentration was analyzed in samples collected intermittently by end-expiratory technique. A rise in breath hydrogen concentration of 20 PPM over baseline was considered evidence of lactose malabsorption.

RESULTS

The twenty-five subjects were twenty females (80.0%) and five males (20.0%) who ranged in age from 18 to 53 years (mean 31 +/- 8.29). Sixteen subjects belonged to the finger shaped villi group (64.0%), five to the mixed finger and leaf shaped villi, group (20.0%) and four to the clubbing or blunting shaped villi group (16.0%). Results of breath hydrogen excretion test identified the prevalence of lactose intolerance in 68 per cent of the subjects: 15/16 (93.75%) of group I; 1/5 (20.0%) of group II and 1/4 (25%) of group III respectively (P<0.001). The symptom of diarrhea after lactose loading was correlated well in patients who had positive breath hydrogen analysis.

CONCLUSION

As shown in this study, the lactose intolerance is not related to intestinal villi morphology. It is implied that primary lactase deficiency is more common in Thai people than secondary lactase deficiency.

The impact of HIV infection on lactose absorptive capacity

Forty HIV-infected adult patients at different disease stages and 44 healthy volunteers were evaluated for lactose malabsorption using the hydrogen breath test after 20 g lactose ingestion. All subjects were previously tested for breath hydrogen (H2) excretion after 12 g lactulose ingestion. The presence of intestinal superinfections, gastrointestinal symptoms and the intensity of clinical intolerance after lactose load were accurately searched in each patient. The cumulative H2 excretion after lactulose did not significantly differ between the different groups studied. The prevalence of lactose malabsorption turned out to be significantly higher (P < 0.001) in HIV-infected patients (70%) than in controls (34%). Moreover, in patients in more advanced disease stages the degree of lactose malabsorption was significantly greater than in patients at earlier disease stages, who did not differ from healthy volunteers. Furthermore the degree of lactose intolerance was significantly greater (P < 0.001) in symptomatic patients than in those without intestinal symptoms and in healthy volunteers, while no significant difference was observed between these latter groups. The results here demonstrate the negative impact of HIV infection on lactose absorptive capacity in adult patients, particularly marked in more advanced stages of the disease, suggesting that, in addition to the presence of the virus alone, other factors may contribute to determine the enterokinetic alterations responsible for lactase deficiency.

A retrospective assessment of the clinical value of jejunal disaccharidase analysis

BACKGROUND

The measurement of jejunal disaccharidases is used by several gastroenterologists when investigating suspected small-bowel disease. The clinical value of this analysis is assessed.

METHOD

The histology and disaccharidase results in 1585 jejunal biopsy specimens were reviewed retrospectively.

RESULTS

Disaccharidase and histology results concurred in most cases (72%). However, disaccharidases were an insensitive indicator of small-bowel disease: low levels were found in only 65% of coeliac patients with villous atrophy, 15% of patients with giardiasis, and 6% of patients with villous atrophy associated with non-coeliac histology. Low disaccharidase levels were sometimes found in patients with normal histology (1.6%) and when biopsy specimens were unwittingly taken from non-jejunal sites (1.4%). Isolated low lactase activities were found in 3.2%. Usually this finding was not clinically relevant because patients had no symptoms of lactose intolerance (38%), had another diagnosis that responded to appropriate treatment (8%), or had no response to a low-lactose diet (14%). In 16 patients sucrase activities were markedly low, and this investigation proved central to the diagnosis of sucrase-alpha-dextrinase deficiency, which was subsequently confirmed in 9.

CONCLUSION

Jejunal disaccharidases are clinically useful only in the diagnosis of sucrase-alpha-dextrinase deficiency. We recommend that their measurement be reserved for the investigation of patients suspected of having this condition.

Enteric disease in early childhood inhibits microvillus expression by potential stem cells

1. Enterocyte development of microvillus structure has been measured in intestinal biopsies obtained from children suffering from coeliac disease, cow's milk protein intolerance and microvillus atrophy, and the results compared with similar measurements carried out in control children. 2. All types of enteric disease caused a significant 30% reduction in the length of microvilli present on undifferentiated basal crypt enterocytes, here referred to as potential stem cells. 3. Microvillus growth measured in control enterocytes took place mainly over the basal third of the villus. There was then little further change in structure during subsequent enterocyte migration to the villus tip. 4. Microvillus length in diseased tissue remained more or less constant during enterocyte migration to the crypt-villus junction. Microvillus length then decreased slightly during subsequent enterocyte migration over stunted villi. 5. The present results are discussed in relation to the supposed properties of potential stem cells. Comparisons are also made between profiles of microvillus development measured in healthy children and mature adults.

Influence of cow's milk proteins and gluten on human duodenal mucosa in organ culture

Forty-five duodenal biopsies from 33 children and 3 adult patients were maintained in organ culture for 24 h and exposed to various cow's milk proteins and gluten. In 10 of 11 celiac patients with a flat duodenal mucosa, and in 2 of 4 patients with partial villous atrophy, a significant reduction in the mean enterocyte height was found after in vitro gluten exposure, compared to culture in basic culture medium. Three patients had coexisting celiac disease and cow's milk protein intolerance. alpha-Lactalbumin and beta-lactoglobulin exhibited toxic effects on flat biopsies from two of these patients, and casein was toxic in one. In 10 patients with cow's milk protein intolerance, a significant reduction in enterocyte height was noted in one case with gluten, and in three patients with casein and lactoglobulin, whereas lactalbumin did not affect the tissues. In seven control patients having a normal duodenal mucosa, no in vitro influences were noted, whereas in four patients with partial villous atrophy, a toxic reaction to gluten was seen in one and a reduced enterocyte height was seen after lactoglobulin exposure in another. In vitro toxicity induced by gluten corresponded well with the diagnosis of celiac disease, whereas toxic reactions to cow's milk proteins during organ culture were inconsistent in cow's milk intolerance, except for cases in which a marked enteropathy was documented.

[51Cr]EDTA intestinal permeability in children with cow's milk intolerance

Making use of [51Cr]EDTA as a permeability marker, we measured intestinal permeability in a group of 20 children with proven cow's milk intolerance (CMI), a group of 17 children with similar complaints where CMI was excluded (sick controls), and a group of 12 control children. [51Cr]EDTA test results (mean +/- SD) were 6.85 +/- 3.64%, 3.42 +/- 0.94%, and 2.61 +/- 0.67% in the group with CMI, the sick control, and the control group, respectively. When compared to both control groups, patients with cow's milk intolerance (CMI) showed a significantly increased small bowel permeability. We conclude that the [51Cr]EDTA test can be helpful for the diagnosis of cow's milk intolerance.

Is the assay of disaccharidase activity in small bowel mucosal biopsy relevant for clinical gastroenterologists?

In a retrospective study, jejunal mucosal disaccharidase and alkaline phosphatase activities have been investigated in 40 controls and patients with proven celiac sprue (n = 26), lactase deficiency (n = 26), osteoporosis or osteomalacia (n = 16), chronic pancreatitis (n = 12), giardiasis (n = 7), or Crohn's disease (n = 7). Apart from a nonselective reduction of mucosal enzyme activities in the sprue syndrome and a selective reduction of lactase activity in the patients with primary lactase deficiency, assays of mucosal disaccharidases revealed only inconstant or slight deviations from the control group and were not of diagnostic significance for any of the above-mentioned disorders. Isolated forms of enzyme deficiencies other than lactase deficiency, such as sucrase-isomaltase or trehalase deficiency were not present among 168 investigations carried out from 1972-1982. It is concluded that assay of small intestinal disaccharidase or alkaline phosphatase activities does not expand the diagnostic impact of morphological examination of small bowel biopsy specimens and modern noninvasive methods for the detection of carbohydrate malabsorption. Thus, the method does not appear a necessary or relevant investigation in routine clinical practice.

Lactose malabsorption in adult patients with Crohn's disease

In order to evaluate, in adult patients with Crohn's disease (CD), the prevalence of lactose malabsorption and intolerance, and the percentage who can tolerate a physiologic amount of milk in their diet, we tested 37 patients with CD (19 with intestinal resection, and 18 without) and 67 healthy controls (C) with the H2-breath test after they had ingested increasing loads of lactose as 10% solution (12.5 g, 25 g, and 50 g). Patients with malabsorption after the 12.5-g dose were tested further with 250 ml of milk. In the total group of patients and in the subgroup of those with resection, the prevalence of malabsorption was higher than in controls at all lactose loads; in patients who had not undergone resection, no significant difference was observed with the 12.5-g dose. Eleven of 18 patients who were malabsorbers with the 12.5-g dose had malabsorption also with 250 ml milk; however, only three of them (8% of the total group) experienced symptoms of intolerance. We conclude that, in adult patients with CD, 1) the prevalence of lactose malabsorption is increased, 2) in patients who have undergone intestinal resection, malabsorption occurs at a lower dose of the sugar than in patients who did not, and 3) since only 8% of patients experienced symptoms of intolerance after the ingestion of milk 250 ml, this amount can be empirically inserted in the daily diet of an adult with CD.

Effect of continued feeding of cows' milk on asymptomatic infants with milk protein sensitive enteropathy

The clinical response and the histological changes in the mucosa of the small bowel in response to continued feeding with cows' milk protein were assessed over a period of 2-6 weeks in 24 infants who had shown histological changes without immediate clinical symptoms after challenge with a diet containing cows' milk protein. Twenty of the 24 infants (83%) thrived well on cows' milk protein. Jejunal biopsy specimens taken six to eight weeks after the initial biopsy showed histological improvement in all 20 infants compared with biopsy specimens taken soon after the challenge, which had shown mucosal damage. The mucosa had returned to normal in 12, was mildly abnormal in seven, and moderately abnormal in one. Corresponding improvements in the activities of mucosal enzymes were seen. In four of the 24 infants (17%) symptoms developed between three and six weeks. Histological examination of the jejunal biopsy specimens showed that mucosal damage had progressed in two, and remained the same in two; moreover, the disaccharidase activities remained depressed. The present study shows that most infants with enteropathy caused by sensitivity to cows' milk protein but without clinical symptoms develop tolerance to the protein and the mucosa returns to normal despite continued feeding with cows' milk protein.

Clinical heterogeneity in infantile galactosialidosis

A new case of infantile galactosialidosis is presented. The condition was diagnosed when the patient was 4 months of age and she died at 20 months. She exhibited some of the symptoms of classical infantile galactosialidosis but no corneal clouding, cherry-red macular spot or limitation of joint mobility. Sonographic examination showed large kidneys and thickened cardiac septa, two symptoms as yet undescribed in this disorder. Urinary oligosaccharide analysis gave grossly pathological results and subsequent fibroblast enzyme analysis showed a deficiency of alpha-neuraminidase and beta-galactosidase. The patient's clinical features are compared with the few cases so far described in the literature.

Differences between lactase deficient and non-lactase deficient women with spinal osteoporosis

Both osteoporosis and lactase deficiency are seen commonly in the United States. Since the latter may lead to avoidance of calcium sources and may exacerbate the bone disease in populations at risk, we studied lactose tolerance and histomorphometrically analyzed undecalcified transiliac bone biopsies in a consecutive group of postmenopausal women with the osteoporotic spinal compression fracture syndrome. Oral lactose tolerance tests prior to the biopsy clearly separated two groups. Sixty-five percent had abnormal test results. The bone biopsies in the lactase deficient group showed more osteoid volume and osteoid seam widths on examined trabecular bone. Analysis of tetracycline-labeled bone revealed significant increases in both single, double, combined single and double tetracycline labels, and the percent osteoid labeled with tetracycline. There was no difference in the calcification rates. These findings indicate different mineralization activity in lactase deficient patients, possibly reflecting their lower dietary calcium intake.

Cow's milk protein-sensitive enteropathy: number and timing of biopsies for diagnosis

Intestinal biopsy is an essential procedure in the diagnosis of cow's milk protein-sensitive enteropathy. The number and timing of biopsies, however, is still controversial. Twenty-two infants who were clinically suspected of having cow's milk protein intolerance were put on a milk-free diet, during which they all improved. In the first 14 infants (Group I), milk withdrawal lasted 6-8 weeks; in the following 8 infants (Group II), milk withdrawal lasted 3.5-4 months. At the end of the withdrawal period, each patient was submitted to an oral lactose tolerance test and then to a first jejunal biopsy, followed by a cow's milk challenge, and a second biopsy (1-2 days later). None of the infants showed evidence of lactose intolerance, but they all reacted adversely to milk reintroduction. In Group I, the distribution of mucosae from grade 0 (normal) to III was almost the same before and after challenge (p greater than 0.5); this is considered to be due to the severe mucosal damage still present in prechallenge biopsies. In Group II, however, a significant difference was found in the distribution of mucosae before and after challenge (p less than 0.05), and a deterioration could be observed in each case after challenge. Intraepithelial lymphocyte counts and mitotic index determinations before and after milk reintroduction were of no diagnostic value in either group. It is suggested that the diagnosis of cow's milk protein-sensitive enteropathy may rely on two biopsies, the first after a period of 3.5-4 months on milk-free diet and the second following milk challenge.

Value of breath hydrogen analysis in management of diarrheal illness in childhood: comparison with duodenal biopsy

Breath hydrogen tests were carried out on 157 children either because they had chronic diarrhea or because they were on disaccharide-free diets. Lactose malabsorption was common in patients with postgastroenteritis syndrome (43%), and sucrose malabsorption was readily detected in patients with congenital sucrase-isomaltase deficiency. Secondary sucrose malabsorption and small bowel bacterial overgrowth were also detected. In predicting clinical response to dietary change, the breath hydrogen test, as we perform it, was clearly the most specific and sensitive and had a predictive accuracy of 96%. Duodenal biopsy results obtained from 48 of the children gave a 23% incidence of misleading disaccharidase results (16.7% falsely normal, 6.3% falsely abnormal), but biopsy remains vital in the diagnosis of congenital sucrase-isomaltase deficiency. False negative breath hydrogen results were obtained on occasions (4%) but in most instances were related to recent antimicrobial therapy or failure of the breath test mechanics (e.g., vomiting, length of sampling).

Ultrastructural study on a severe infantile sialidosis (beta-galactosidase-alpha-neuraminidase deficiency)

This study was undertaken to elucidate ultrastructural changes in a severe infantile sialidosis. The materials examined in this study consisted of biopsied rectal mucosa and autopsied small intestine, liver and kidney. In the biopsy sample, axons contained a number of pleomorphic electron dense bodies, and numerous membrane-bound vacuoles were found in Schwann's cells, fibroblasts, endothelial cells, lymphocytes and plasma cells. In autopsy samples, neurons in Auerbach's myenteric plexus of the small intestine were filled with a number of membranous cytoplasmic bodies, pleomorphic dense bodies and vesicles containing dense materials. Hepatocytes in the liver, and glomerular and tubular epithelial cells in the kidney were also extended by a number of membrane-bound vacuoles. These ultrastructural changes in severe infantile sialidosis closely resemble those in GM1-gangliosidosis type 1.

Diagnostic role of skin or conjunctival biopsies in neurological disorders. An update

Updated figures from our reports on electron microscopy of skin or conjunctival biopsies include 256 patients, mostly suffering from lysosomal diseases. Significant morphological data supportive of the diagnosis and additional to enzyme assay (when and if an assay is available for the disorder) were discovered in 95% of the cases. Equivocal or negative data amounted to 5%. The present paper deals with some metabolic disorders which had not been fully dealt with in our previous publications and with an extension of the indications of skin biopsies: adult form and atypical variants of ceroid-lipofuscinoses, galactosialidosis, mucolipidosis IV, infantile neuroaxonal dystrophy, Lafora's disease, cardiomyopathy with generalized accumulation of intermediate filaments and congenital hypomyelination neuropathy. A comparison between biopsy and autopsy material in storage diseases shows that the storage of inclusions does not remain limited to one cell type or to one tissue even if no clinical signs are detectable. This ubiquitous character of the storage can be used for diagnostic purposes. On the other hand, the membrane-bound inclusions are not necessarily similar in all cell types and the search for characteristic features can be difficult in adult patients. Finally it is evident that skin biopsies can be used in other conditions than lysosomal disorders. The applicability of this procedure to other diseases needs further exploratory work.

Quantitative analysis of small intestinal mucosa in cow's milk-sensitive enteropathy

The appearance of the small intestinal mucosa in cow's milk protein intolerance (CMPI) was studied using quantitative morphometry. The parameters under study were the numbers of eosinophil cells in the lamina propria and epithelium, villous height, crypt zone depth, villous height/crypt zone depth ratio, and total mucosal thickness. Tracings of whole sections were analysed using a suitably programmed minicomputer linked to a digitising table. Small bowel biopsy specimens from children with untreated CMPI, from children before and after clinical relapse on cow's milk challenges, and from children with resolved CMPI were compared to each other, to those from control infants, and to those from children with coeliac disease. No change of diagnostic significance could be found in the number of lamina propria eosinophil cells, but levels of intraepithelial eosinophils were significantly increased following cow's milk challenge. Quantification of mucosal dimensions confirmed the presence of a cow's milk-sensitive enteropathy and established the finding of a thin mucosa in CMPI regardless of clinical disease activity. Mucosal thickness was not different from control values following resolution of the disease. In coeliac disease mucosal thickness was significantly greater than in CMPI (apart from young children with untreated coeliac disease whose mucosa was not thicker than that of children with untreated CMPI) but not different from control values. It is suggested that in CMPI there is a limitation in the capacity of crypt cells to compensate for the loss of villous epithelium.

Mast cells and eosinophils in the jejunal mucosa of patients with intestinal cow's milk allergy and celiac disease of childhood

We counted the number of granulated mast cells with high iron diamine staining, and the number of eosinophils with hematoxyline-eosin staining, in the lamina propria of the jejunum in 12 untreated patients with intestinal cow's milk allergy (CMA), 47 with celiac disease (CD), and 14 controls. A decreased number of mast cells and an increased number of eosinophils were found in 58% of patients with CMA, and in 60% of those with CD. The number of mast cells showed a significant positive correlation with the villous height, and the number of eosinophils a negative correlation with both the villous height, and the number of mast cells. Appropriate dietary treatment resulted in a rise in the number of granulated mast cells and a decrease in the number of eosinophils in both patient groups.

Complementation, cross correction, and drug correction studies of combined beta-galactosidase neuraminidase deficiency in human fibroblasts

Neuraminidase activity in fibroblasts obtained from a patient with combined beta-galactosidase-neuraminidase deficiency (beta-gal-/neur-) was partially restored by fusion with two ML I cell lines and an ML II cell line. As observed with neuraminidase activity, beta-galactosidase also showed complementation with an increase in activity when beta-gal-/neur- fibroblasts were fused with an ML II or a GMI gangliosidosis cell line. Both GMI gangliosidosis and sialidosis fibroblasts secreted a "corrective factor" which, when added to medium above beta-gal-/neur- fibroblasts, was pinocytosed and partially corrected its deficiencies for these two enzymes. This partial correction of beta-galactosidase and neuraminidase activities persisted for at least 72 h after removal of the "corrective factor" from the medium. A "corrective factor" with similar properties was obtained from glycoproteins isolated by chromatography of human spleen homogenates on concanavalin A-Sepharose. Treatment of beta-gal-/neur- fibroblasts with leupeptin or EP475, two inhibitors of lysosomal thiol-proteases, partially restored beta-galactosidase activity but caused no significant improvement in neuraminidase levels. The partial corrective effect of leupeptin on beta-galactosidase activity persisted for at least 2 d after removal of the drug, even in the presence of cycloheximide.

Morquio-B disease, spondyloepiphyseal dysplasia associated with acid beta-galactosidase deficiency. Report of three cases in one family

Two sisters and one brother, all with normal intelligence and no evidence of neurological abnormality, present progressive spondyloepiphyseal dysplasia, stunted growth, corneal opacities, and increased keratansulfaturia. Cultured skin fibroblasts from one of the children showed a remarkable deficiency of acid beta-galactosidase in association with normal activities of N-acetylgalactosamine-6-sulfate sulfatase and sialidase. Acid beta-galactosidase was also deficient in leukocytes of two children. Leukocytes of the parents exhibited intermediate activities, which suggests the primary nature of beta-galactosidase deficiency. Patients with MPS IV-B may be severely affected.

Neuropathological findings of an autopsy case of adult beta-galactosidase and neuraminidase deficiency

An autopsy case of a Japanese male with familial beta-galactosidase and neuraminidase deficiency is reported. The clinical picture was characterized by adult onset, a gargoyle-like face, cerebellar ataxia, myoclonus, convulsions, retinal degeneration and cortical blindness. Histopathologically, most neurons seemed to have become degenerated in the whole cerebral cortex. Moreover, the calcarine cortex appeared spongy with depopulation of nerve cells. Stuffed neurons or neuronal storage changes were found throughout the brain, especially in the motor nuclei of the spinal cord and brain stem. The inclusions in the stuffed neurons revealed various profiles on the electron microscope. They were composed of membranous lamellar and/or multilamellar structures, often accompanying vacuoles and reminiscent of lipofuscin-like profiles.

Mucosal function and breath hydrogen excretion: comparative studies in the clinical evaluation of children with nonspecific abdominal complaints

To evaluate the role of the lactose breath hydrogen test for the detection of lactose malabsorption in children with chronic nonspecific abdominal complaints, breath hydrogen excretion was measured in 131 children with recurrent abdominal pain (n = 75) or chronic nonspecific diarrhea (n = 56) following a lactose load (2 gm/kg; maximum 50 gm). The data were compared to those obtained from lactose tolerance tests (n = 113) and symptom response following a lactose load (n = 109) performed simultaneously with the lactose breath hydrogen test, and with results from small bowel biopsies obtained in 31 children to determine dissacharidase activity and mucosal histology. The results indicate that an increase in breath hydrogen of greater than 10 ppm above base line values (delta ppm) by 120 minutes ("early increase" response) completely discriminates between biopsy-proven isolated lactase-insufficient and lactase-sufficient children. A similar increase after 120 minutes ("late increase" response) is consistent both with normal mucosal function and partial lactase insufficiency due to mucosal injury. Breath hydrogen responses predicted assayed lactase activity in all patients with isolated lactase insufficiency, but were "falsely negative" in four of ten children whose lactase insufficiency was secondary to mucosal injury. In both clinical groups, lactose malabsorbers report significantly more symptoms than absorbers (P less than .001), but neither symptom reports nor tolerance tests are accurate methods for distinguishing lactose malabsorbers from absorbers. Although the lactose breath hydrogen test provides objective documentation of lactose malabsorption, it is equally predictive of assayed lactase activity in all clinical groups.

Disaccharidase-deficient animals have normal ultrastructure of intestinal brush border membranes

The intestinal disaccharidases, lactase, sucrase-isomaltase complex, and glucoamylase are proteins intimately associated with the brush-border membrane of the epithelial cell. These three enzyme activities are found in the intestine of the adult rat; lactase and glucoamylase activities are primarily associated with the intestine of the infant rat. Only glucoamylase and isomaltase activities are detected in the intestine of the California sea lion, Zalophus californianus. The activities of these enzymes are detected only in villus cells, and not in crypt cells. We have carried out electron microscopic studies of negatively stained brush-border preparations of intestinal crypt and villus cells; from the intestine of the 10-day-old rat and from that of the California sea lion. The density of the knob-like structures protruding from the brush-border membranes was not significantly different in any of these preparations. The diameter of the knobs on the preparations from crypt cells was smaller than the diameters of the knobs found on membranes prepared from the other sources. These data are discussed in terms of the relationship between the presence of knob structures and disaccharides activities associated with the brush-border membranes.

Intestinal disaccharidase activities in relation to age, race, and mucosal damage

Studies were undertaken to determine the relationship of intestinal disaccharidase activity to age and race, and the relationship of mucosal damage to a primary low lactase activity. The first study consisted of data on 399 persons (339 whites, 53 blacks, and 7 American Indians) ages 1 month to 93 years, with normal intestinal histology. Among whites, all 117 children 5 years old or under had high lactase levels, whereas low levels were found only in subjects over 5 years of age. No low lactase levels were identified among the 11 black children 3 years old or under, but in comparison to coetaneous white children, their mean lactase activity was signficantly less. The majority of older blacks had low lactases. In whites and blacks alpha-disaccharidases did not participate in the age-related changes demonstrated with lactase. Of the 7 American Indians, none under 26 months old had low lactase levels, whereas the 4 over 10 years old had low activities. Heterozygotes for sucrase-isomaltase deficiency were identified only among whites. Low lactase levels developed during childhood in all races studied, however, many for unknown reasons maintained their lactose tolerance until adulthood. In the second study of 13 additional children with secondary disaccharidase deficiencies, emergence of a primary low lactase was related to age and race, rather than to mucosal damage. It appears that primary low intestinal lactase levels are absent or rare in whites under 5 and blacks under 3 years of age, and the deficiency is not related to mucosal damage.

Reinvestigation of lactose intolerant children: lack of correlation between continuing lactose intolerance and small intestinal morphology, disaccharidase activity, and lactose tolerance tests

Thirty children on a lactose-free diet aged from 2-38 months who had previously been diagnosed as having secondary lactose intolerance were reinvestigated on 32 occasions by an oral lactose tolerance test, small intestinal biopsy, and measurement of disaccharidase activity in order to detect the presence of continuing lactose intolerance before reintroduction of milk. No correlation was found between continuing lactose intolerance, as diagnosed by the development of watery stools containing excess reducing substances after an oral load of lactose, and maximum blood glucose rise during a lactose tolerance test, lactase levels, and small intestinal morphology.

Sugar absorption by small bowel biopsy samples from patients with primary lactase deficiency and with adult celiac disease

The present study was undertaken to compare the 3-O-methyl-D-glucose (3MG) absorption by jejunal biopsies from normal human subjects (N = 3) with that by the jejunum of the rat (N = 8) and of the hamster (N = 8), and to examine whether jejunal biopsies from normal subjects (N = 3), patients with primary lactase deficiency (N = 5) and from patients with celiac sprue (N = 5) follow the same pattern of sugar absorption as usually observed in vivo. The results indicate that under the conditions of our experiments the estimated affinity of carrier for 3MG (ie, apparent Km) in the biopsies from normal subjects did not differ significantly from that in rat or hamster jejunum. The estimated capacity of carriers for 3MG absorption (ie, Vmax) appeared to be similar in biopsies from normal subjects and in hamster jejunum, but significantly lower in rat jejunum. There was no difference in apparent Km between the biopsies from normal subjects and those from the patients with lactase deficiency. Although the Vmax for the lactase deficient patients was substantially higher than that for the normal subjects, the difference was not statistically significant. The absorption of 3MG by the biopsies from patients with celiac sprue did not follow Michaelis-Menten kinetics and was compatible with that of passive diffusion or low saturation conditions. Since the intracellular concentration of 3MG in all biopsies from celiac patients exceeded the concentration of the media, sugar transport could not have occurred by diffusion, and it is concluded that the absence of Michaelis-Menten kinetics was the result of low saturation conditions. This active transport with low saturation kinetics in patients with celiac disease suggests that in these patients not only the number of functioning carrier molecules is diminished but also the affinity of the existing carrier for sugar molecule is reduced. This situation, at least in some patients, seems to improve after treatment with gluten-free diet.

The intestinal microvillus. Ultrastructural variability in coeliac disease and cow's milk intolerance

In 8 patients with coeliac disease, 2 patients with cow's milk intolerance and 10 patients with other gastrointestinal disturbances, intestinal biopsies were examined in order to compare the extent of alteration of surface vs. crypt microvilli (MV). In those diseases associated with the ingestion of a noxious agent, namely coeliac disease and cow's milk intolerance, a marked and abrupt difference between the severely damaged surface epithelium and its MV, and the preserved crypt epithelium was noted. The results of the examinations give reason to suppose that these morphological variations are caused by the higher gliadin or milk protein concentration over the avillous surface epithelium as opposed to the lower one in the elongated crypts.