The gut microbiome modulates the impact of Anaerobutyricum soehngenii supplementation on glucose homeostasis in mice.

Background There is growing interest in the development of next-generation probiotics to prevent or treat metabolic syndrome. Previous studies suggested that Anaerobutyricum soehngenii may represent a promising probiotic candidate. A recent human study showed that while A . soehngenii supplementation is well tolerated and safe, it resulted in variable responses among individuals with a subset of the subjects significantly benefiting from the treatment. We hypothesized that gut microbiome variation is linked to the heterogeneous responses to A . soehngenii treatment observed in humans. Results We colonized germ-free mice with fecal microbiota from human subjects that responded to A . soehngenii treatment (R65 and R55) and non-responder subjects (N96 and N40). Colonized mice were fed a high-fat diet (45% kcal from fat) to induce insulin resistance, and orally treated with either live A . soehngenii culture or heat-killed culture. We found that R65-colonized mice received a benefit in glycemic control with live A . soehngenii treatment while mice colonized with microbiota from the other donors did not. The glucose homeostasis improvements observed in R65-colonized mice were positively correlated with levels of cecal propionate, an association that was reversed in N40-colonized mice. To test whether the microbiome modulates the effects of propionate, R65- or N40-colonized mice were treated with tripropionin (TP, glycerol tripropionate), a pro-drug of propionate, or glycerol (control). TP supplementation showed a similar response pattern as that observed in live A . soehngenii treatment, suggesting that propionate may mediate the effects of A . soehngenii . We also found that TP supplementation to conventional mice reduces adiposity, improves glycemic control, and reduces plasma insulin compared to control animals supplemented with glycerol. Conclusions These findings highlight the importance of the microbiome on glycemic control and underscore the need to better understand personal microbiome-by-therapeutic interactions to develop more effective treatment strategies.

Gut butyrate-producers confer post-infarction cardiac protection.

The gut microbiome and its metabolites are increasingly implicated in several cardiovascular diseases, but their role in human myocardial infarction (MI) injury responses have yet to be established. To address this, we examined stool samples from 77 ST-elevation MI (STEMI) patients using 16 S V3-V4 next-generation sequencing, metagenomics and machine learning. Our analysis identified an enriched population of butyrate-producing bacteria. These findings were then validated using a controlled ischemia/reperfusion model using eight nonhuman primates. To elucidate mechanisms, we inoculated gnotobiotic mice with these bacteria and found that they can produce beta-hydroxybutyrate, supporting cardiac function post-MI. This was further confirmed using HMGCS2-deficient mice which lack endogenous ketogenesis and have poor outcomes after MI. Inoculation increased plasma ketone levels and provided significant improvements in cardiac function post-MI. Together, this demonstrates a previously unknown role of gut butyrate-producers in the post-MI response.

Contrasting recruitment of skin-associated adipose depots during cold challenge of mouse and human.

KEY POINTS: Several distinct strategies produce and conserve heat to maintain the body temperature of mammals, each associated with unique physiologies, with consequences for wellness and disease susceptibility Highly regulated properties of skin offset the total requirement for heat production  We hypothesize that the adipose component of skin is primarily responsible for modulating heat flux; here we evaluate the relative regulation of adipose depots in mouse and human, to test their recruitment to heat production and conservation We found that insulating mouse dermal white adipose tissue accumulates in response to environmentally and genetically induced cool stress; this layer is one of two adipose depots closely apposed to mouse skin, where the subcutaneous mammary gland fat pads are actively recruited to heat production In contrast, the body-wide adipose depot associated with human skin produces heat directly, potentially creating an alternative to the centrally regulated brown adipose tissue ABSTRACT: Mammalian skin impacts metabolic efficiency system-wide, controlling the rate of heat loss and consequent heat production. Here we compare the unique fat depots associated with mouse and human skin, to determine whether they have corresponding functions and regulation. For humans, we assay a skin-associated fat (SAF) body-wide depot to distinguish it from the subcutaneous fat pads characteristic of the abdomen and upper limbs. We show that the thickness of SAF is not related to general adiposity; it is much thicker (1.6-fold) in women than men, and highly subject-specific. We used molecular and cellular assays of ß-adrenergic-induced lipolysis and found that dermal white adipose tissue (dWAT) in mice is resistant to lipolysis; in contrast, the body-wide human SAF depot becomes lipolytic, generating heat in response to ß-adrenergic stimulation. In mice challenged to make more heat to maintain body temperature (either environmentally or genetically), there is a compensatory increase in thickness of dWAT: a corresponding ß-adrenergic stimulation of human skin adipose (in vivo or in explant) depletes adipocyte lipid content. We summarize the regulation of skin-associated adipocytes by age, sex and adiposity, for both species. We conclude that the body-wide dWAT depot of mice shows unique regulation that enables it to be deployed for heat preservation; combined with the actively lipolytic subcutaneous mammary fat pads they enable thermal defence. The adipose tissue that covers human subjects produces heat directly, providing an alternative to the brown adipose tissues.

Evaporative cooling provides a major metabolic energy sink.

OBJECTIVE: Elimination of food calories as heat could help redress the excess accumulation of metabolic energy exhibited as obesity. Prior studies have focused on the induction of thermogenesis in beige and brown adipose tissues as the application of this principle, particularly because the ß-adrenergic environment associated with thermogenic activation has been shown to have positive health implications. The counterpoint to this strategy is the regulation of heat loss; we propose that mammals with inefficient heat conservation will require more thermogenesis to maintain body temperature. METHODS: Surface temperature thermography and rates of trans-epidermal water loss were integrated to profile the total heat transfer of genetically-engineered and genetically variable mice. RESULTS: These data were incorporated with energy expenditure data to generate a biophysical profile to test the significance of increased rates of evaporative cooling. CONCLUSIONS: We show that mouse skins vary considerably in their heat retention properties, whether because of naturally occurring variation (SKH-1 mice), or genetic modification of the heat-retaining lipid lamellae (SCD1, DGAT1 or Agouti Ay obese mice). In particular, we turn attention to widely different rates of evaporative cooling as the result of trans-epidermal water loss; higher rates of heat loss by evaporative cooling leads to increased demand for thermogenesis. We speculate that this physiology could be harnessed to create an energy sink to assist with strategies aimed at treating metabolic diseases.

Dermal white adipose tissue: a new component of the thermogenic response.

Recent literature suggests that the layer of adipocytes embedded in the skin below the dermis is far from being an inert spacer material. Instead, this layer of dermal white adipose tissue (dWAT) is a regulated lipid layer that comprises a crucial environmental defense. Among all the classes of biological molecules, lipids have the lowest thermal conductance and highest insulation potential. This property can be exploited by mammals to reduce heat loss, suppress brown adipose tissue activation, reduce the activation of thermogenic programs, and increase metabolic efficiency. Furthermore, this layer responds to bacterial challenge to provide a physical barrier and antimicrobial disinfection, and its expansion supports the growth of hair follicles and regenerating skin. In sum, this dWAT layer is a key defensive player with remarkable potential for modifying systemic metabolism, immune function, and physiology. In this review, we discuss the key literature illustrating the properties of this recently recognized adipose depot.

Phosphorylation of glycogen synthase kinase-3ß in metabolically abnormal obesity affects immune stimulation-induced cytokine production.

BACKGROUND: Obesity is a severe health problem worldwide, which leads to multiple comorbidities including type 2 diabetes mellitus and cardiovascular diseases. Inflammation has been found to be an important characteristic of adipose tissue in obese subjects. However, obesity is also associated with compromised immune responses to infections and the impact of obesity on immune function has not been fully understood. SUBJECTS/METHODS: To clarify the role of obesity in the immune responses, we investigated the Toll-like receptor (TLR)-induced cytokine secretion by leukocytes from obese and lean subjects. We also investigated the relationship between insulin-induced intracellular signaling and cytokine production using peripheral blood mononuclear cells (PBMCs) and a monocytic cell line THP-1. RESULTS: We found decreased TLR-induced interferon-γ, interleukin-6 (IL-6) and tumor necrosis factor-α secretions and elevated IL-10 secretion by leukocytes from obese subjects when compared with lean controls. PBMCs from obese subjects showed enhanced basal Akt and glycogen synthase kinase-3ß (GSK-3ß) phosphorylation, which did not further increase with insulin and lipopolysaccharide (LPS) stimulation. We also found that LPS-induced IκBα degradation was inhibited in PBMCs from obese subjects. By using THP-1 cells with GSK-3ß knockdown or cells treated with hyperinsulinemic and high-fatty acid conditions, we found that LPS-induced nuclear factor κB (NF-κB) activation was inhibited and cyclic adenosine monophosphate response element-binding protein (CREB) activation was enhanced. CONCLUSIONS: These findings indicate that GSK-3ß is important in the regulation of NF-κB and CREB activation in leukocytes under the metabolic condition of obesity. Our study revealed a key mechanism through which metabolic abnormalities compromise leukocyte functions in people with obesity.

Efficacy and safety of ribavirin plus pegylated interferon alfa in geriatric patients with chronic hepatitis C.

BACKGROUND: Limited data are available on the efficacy and safety of antiviral therapy in geriatric patients with chronic hepatitis C virus (HCV) infection. AIM: To evaluate the efficacy and safety of pegylated interferon (pegIFN) plus ribavirin (RBV) therapy in geriatric HCV-infected patients. METHODS: Ninety-one geriatric patients (age ≥65 years; the elderly group) with HCV infection and 91 gender- and HCV genotype-matched middle-aged patients (age 50-64 years; the younger group) were assigned to receive weekly pegIFN injection plus weight-based oral RBV for 24 weeks. The on- and off-treatment virological responses were evaluated for treatment efficacy. RESULTS: In intention-to-treat analysis, the sustained virological response (SVR) rate was substantially decreased in the elderly patients (elderly group vs. younger group, 40.7% vs. 61.5%, respectively; P = 0.005). The SVR rate was significantly lower in geriatric patients than in middle-aged patients with HCV genotype non-1 (54.3% vs. 82.9%; P = 0.01), but the difference was not significant with HCV genotype 1 (32.1% vs. 48.2%; P = 0.083). Furthermore, the older patients infected with HCV genotype non-1 who achieved a rapid virological response had a similar SVR rate to that of the younger patients. The withdrawal rate was 13.2% in the elderly group and 7.7% in the younger group. CONCLUSIONS: Compared with middle-aged patients, the therapeutic efficacy of pegylated interferon plus ribavirin therapy is lower in hepatitis C virus-infected geriatric patients with an acceptable withdrawal rate. Considering prolonged lifespan in geriatric patients, we recommend treating geriatric hepatitis C virus-infected patients who have significant hepatic fibrosis and no other health problems.

Elucidating therapeutic effects on patients with hepatocellular carcinoma and main portal vein thrombosis.

BACKGROUND/AIMS: The survival duration for patients diagnosed with hepatocellular carcinoma (HCC) with main portal vein thrombosis (MPVT) was usually less than 3 months. The aim of this study is to elucidate whether treatment can prolong the survival for such patients. METHODOLOGY: Retrospectively we analyzed the clinical features and outcomes of 63 patients with HCC and MPVT over a 7-year period. Three therapeutic modalities--transcatheter arterial chemotherapy (TAC) with or without radiotherapy (RT), and systemic chemotherapy--were applied. RESULTS: The patients were divided into two groups: 34 (54%) patients were treated, while the remaining 29 (46%) were not. Multivariate analysis revealed that Child-Pugh class, Okuda stage for HCC and the presence of treatment were the principal factors to predict survival. The survival was significantly longer in treated patients than those untreated both in the Child-Pugh class A or B patients. Significantly longer survival is evident in patients treated by TAC combing RT compared to those underwent TAC alone, systemic chemotherapy or no treatment. CONCLUSIONS: The survival of Child-Pugh class A or B patients can be extended by the use of an appropriate therapeutic modality. TAC combined with RT did the best benefit to prolong survival in such patients.

Retinol Esterification by DGAT1 Is Essential for Retinoid Homeostasis in Murine Skin.

Retinoic acid (RA) is a potent signaling molecule that is essential for many biological processes, and its levels are tightly regulated by mechanisms that are only partially understood. The synthesis of RA from its precursor retinol (vitamin A) is an important regulatory mechanism. Therefore, the esterification of retinol with fatty acyl moieties to generate retinyl esters, the main storage form of retinol, may also regulate RA levels. Here we show that the neutral lipid synthesis enzyme acyl-CoA:diacylglycerol acyltransferase 1 (DGAT1) functions as the major acyl-CoA:retinol acyltransferase (ARAT) in murine skin. When dietary retinol is abundant, DGAT1 deficiency results in elevated levels of RA in skin and cyclical hair loss; both are prevented by dietary retinol deprivation. Further, DGAT1-deficient skin exhibits enhanced sensitivity to topically administered retinol. Deletion of the enzyme specifically in the epidermis causes alopecia, indicating that the regulation of RA homeostasis by DGAT1 is autonomous in the epidermis. These findings show that DGAT1 functions as an ARAT in the skin, where it acts to maintain retinoid homeostasis and prevent retinoid toxicity. Our findings may have implications for human skin or hair disorders treated with agents that modulate RA signaling.

Splenic tumour: a clinicopathological study.

Splenic tumours are occasionally found during routine physical check-ups or elective abdominal image studies. Histologically, most splenic tumours are of benign vascular origin. To avoid unnecessary surgery for asymptomatic patients with benign splenic tumours and clarify the clinicopathological features of spleen tumours, this study gathered 44 cases of primary or isolated metastatic spleen tumours confirmed by pathology from surgery specimens or biopsies. The differences in clinicopathological features and image presentations between benign and malignant spleen tumour were investigated. Thirty-two cases involved benign tumours while 12 cases were malignant. Among the benign tumours, vascular originating tumours were most common (with 14 cases of cavernous haemangiomas, 13 cases of lymphangioma, three cases of lymphangiohaemangioma and one case of Littoral cell angioma). Notably, one, case of inflammatory pseudotumour because of Schistosoma parasite infection was also noted. Among the malignant tumours, there were four cases of angiosarcomas with vascular endothelium origins, as well as lymphomas and six metastatic tumours. Image studies were non-specific. Image study alone is an inadequate basis for making differential diagnoses between benign and malignant tumours. Instead, pathological studies are required for a final diagnosis. Using previous studies and this investigation, fine needle aspiration biopsy of spleen tumours with the help of ultrasonic or computed tomography appears a safe and effective method for obtaining biopsy specimens. Splenectomy is recommended only for patients with malignancies or complications such as intractable abdominal pain, coagulopathy or tumour rupture with an unstable haemodynamic state.

Choline deficiency induces apoptosis in primary cultures of fetal neurons.

Treatment of rats with choline during brain development results in long-lasting enhancement of spatial memory whereas choline deficiency has the opposite effect. Changes in rates of apoptosis may be responsible. We previously demonstrated that choline deficiency induced apoptosis in PC12 cells and suggested that interruption of cell cycling due to a decrease in membrane phosphatidylcholine concentration was the critical mechanism. We now examine whether choline deprivation induces apoptosis in nondividing primary neuronal cultures of fetal rat cortex and hippocampus. Choline deficiency induced widespread apoptosis in primary neuronal cells, indicating that cells do not have to be dividing to be sensitive to choline deficiency. When switched to a choline-deficient medium, both types of cells became depleted of choline, phosphocholine and phosphatidylcholine, and in primary neurons neurite outgrowth was dramatically attenuated. Primary cells could be rescued from apoptosis by treatment with phosphocholine or lysophosphatidylcholine. As described previously for PC12 cells, an increase in ceramide (Cer) was associated with choline deficiency-induced apoptosis in primary neurons. The primary neuronal culture appears to be an excellent model to explore the mechanism whereby maternal dietary choline intake modulates apoptosis in the fetal brain.

Chylous ascites in acute pancreatitis during pregnancy: case report.

Chylous ascites is a rare clinical manifestation characterized by ascitic chylomicrons resulting from mechanical obstruction of or leakage from the lymphatic channel. Chronic disorders, especially malignancies, account for most cases of chylous ascites. Acute chylous ascites is less common than the chronic form. We present a rare case of acute chylous ascites secondary to acute pancreatitis during the third trimester of pregnancy. This 24-year-old woman was referred to our emergency department because of severe epigastralgia for several days. Abdominal computed tomography revealed diffuse enlargement of the pancreas and peripancreatic exudation. Massive chylous ascites was found during emergent abdominal exploratory laparotomy. An emergent cesarean section was done because of fetal distress and there was no further accumulation of chyle. A pancreaticocutaneous fistula resulting from the cesarean section was treated successfully with a fistulectomy. In conclusion, chylous ascites is a rare complication of acute pancreatitis. Cesarean section may be helpful in terminating chylous accumulation in acute pancreatitis during the third trimester of pregnancy.

Inhibition of lipid peroxidation by Lactobacillus acidophilus and Bifidobacterium longum.

The inhibition of lipid peroxidation by Lactobacillus acidophilus and Bifidobacterium longum was investigated using two lipid model systems. All eight strains, including six strains of L. acidophilus and two strains of B. longum, demonstrated an inhibitory effect on linoleic acid peroxidation. The inhibitory rates on linoleic acid peroxidation ranged from 33 to 46% when 1 mL of intracellular cell-free extract was tested. In the second model system, the cell membrane of osteoblast was used as the source for biological lipid. The results indicated that all strains were able to protect biological lipids from oxidation. The inhibition rates on cell membrane lipid peroxidation ranged from 22 to 37%. The effect of L. acidophilus and B. longum on inhibition of fluorescent tissue pigment accumulation was also obtained for osteoblastic cells. The inhibition rates on fluorescent tissue pigment accumulation ranged from 20 to 39%. The antioxidative effect of each milliliter of intracellular cell-free extract of L. acidophilus and B. longum was equivalent to 104-172 ppm of butylated hydroxytoluene (BHT). These results indicated that all strains demonstrated high antioxidative activity. The scavenging ability of lipid peroxidation products, tert-butyl hydroperoxide and malondialdehyde, was also evaluated. The results showed that L. acidophilus and B. longum were not able to scavenge the tert-butyl hydroperoxide. Nevertheless, malondialdehyde was scavenged well by these strains.

Antioxidative ability of lactic acid bacteria.

Nineteen strains of lactic acid bacteria were investigated for antioxidative activity. These includedLactobacillus acidophilus B, E, N1, 4356, LA-1, and Farr; Lactobacillus bulgaricus 12 278, 448, 449, Lb, 1006, and 11 842; Streptococcus thermophilus 821, MC, 573, 3641, and 19 987; and Bifidobacterium longum B6 and 15 708. Intracellular cell-free extract of all strains demonstrated antioxidative activity with inhibition rates of ascorbate autoxidation in the range of 7-12%. Antioxidative mechanisms including metal ion chelating ability, scavenge of reactive oxygen species, enzyme inhibition, and reducing activity of intracellular cell-free extract of lactic acid bacteria were studied. S. thermophilus 821 had the highest metal ion chelating ability for Fe(2+), and B. longum 15 708 showed the highest Cu(2+) chelating ability among the 19 strains tested. All strains demonstrated reactive oxygen species scavenging ability. L. acidophilus E showed the highest hydroxyl radical scavenging ability, and B. longum B6 had the best hydrogen peroxide scavenging ability. Reducing activity was also found in all strains. Most of the strains tested demonstrated excellent reducing activity. B. longum B6 showed the highest reducing activity among the 19 strains tested. In enzyme inhibition, superoxide dismutase activity was not found in these 19 strains, and the activity of superoxide dismutase was not induced when metal ion Mn(2+), Fe(2+), or Cu(2+)Zn(2+) was present.

Reactive oxygen species and lipid peroxidation product-scavenging ability of yogurt organisms.

The antioxidative activity of the intracellular extracts of yogurt organisms was investigated. All 11 strains tested, including five strains of Streptococcus thermophilus and six strains of Lactobacillus delbrueckii ssp. bulgaricus, demonstrated an antioxidative effect on the inhibition of linoleic acid peroxidation. The antioxidative effect of intracellular extracts of 10(8) cells of yogurt organisms was equivalent to 25 to 96 ppm butylated hydroxytoluene, which indicated that all strains demonstrated excellent antioxidative activity. The scavenging of reactive oxygen species, hydroxyl radical, and hydrogen peroxide was studied for intracellular extracts of yogurt organisms. All strains showed reactive oxygen species-scavenging ability. Lactobacillus delbrueckii ssp. bulgaricus Lb demonstrated the highest hydroxyl radical-scavenging ability at 234 microM. Streptococcus thermophilus MC and 821 and L. delbrueckii ssp. bulgaricus 448 and 449 scavenged the most hydrogen peroxide at approximately 50 microM. The scavenging ability of lipid peroxidation products, t-butylhydroperoxide and malondialdehyde, was also evaluated. Results showed that the extracts were not able to scavenge the t-butylhydroperoxide. Nevertheless, malondialdehyde was scavenged well by most strains.

High-performance liquid chromatographic method for determination of tramadol in human plasma.

A modified high-performance chromatographic method using UV detection was developed for determination of tramadol concentration in human plasma. Plasma samples were extracted with ethyl acetate in a one-step liquid-liquid extraction (recovery 88.5+/-2.1%). Analysis of the extract was performed on a reversed-phase LiChrospher 60 RP-select B column with a particle size of 5 microm. The mobile phase consisted of 0.05 M KH2PO4 aqueous solution (pH 3.5) and acetonitrile in a ratio of 90:10 (v/v). Metoprolol was used as the internal standard and UV detection at 225 nm was employed. Accuracy of the assay in the concentration range examined was from 1.3 to 11.9% for the intra-day run and from 1.4 to 8.1% for the inter-day run. The precision of this method varied from 1.2 to 8.7%. The reproducibility of the method was determined to be from 0.8 to 7.2% over the six-day period. A limit of detection was 9 ng/ml at a signal-to-noise ratio of 3. This validated method was then applied to the determination of tramadol concentrations in healthy volunteers after oral administration of 100 mg of tramadol in capsules of Painlax and Tramal.

Choline deficiency-induced apoptosis in PC12 cells is associated with diminished membrane phosphatidylcholine and sphingomyelin, accumulation of ceramide and diacylglycerol, and activation of a caspase.

It is not well appreciated that nutritional status can modulate apoptosis, a process that eliminates unwanted or damaged cells. Choline is an essential nutrient, and its absence induces apoptosis. When PC12 cells were cultivated in a choline-free medium, apoptosis was induced (27.4% of cells apoptotic at 72 h as compared to 4.4% in control medium). In choline-free medium at 72 h, there was a 49% decrease in phosphatidylcholine concentration (P<0.01) and a 34% decrease in sphingomyelin concentration (P<0.01); however, there was no change in phosphatidylethanolamine concentration. Before detecting increased apoptosis in choline-deficient cells, we measured a significant increase in ceramide (218% control) and diacyglycerol (155% control) concentrations. The addition of a cell-permeable ceramide to cells in control medium induced apoptosis; however, adding a cell-permeable diacyglycerol did not induce apoptosis. Caspase is a common mediator of apoptosis, and choline deficiency-induced apoptosis was prevented completely by replacing choline or adding a caspase inhibitor into the medium within 48 h of initial choline deprivation. In those cells rescued by replacing choline at 36 h, the concentrations of phosphatidylcholine, sphingomyelin, ceramide, and diacyglycerol returned to levels of control cells. In those cells rescued by adding a caspase inhibitor at 36 h, the concentrations of sphingomyelin and ceramide returned to control levels, but the concentrations of phosphatidylcholine and diacyglycerol did not return to normal. We propose that availability of dietary factors (choline in this model) can modulate apoptosis. Mechanisms that we identify using this model may help us to explain why dietary choline influences brain development.

Multiple lymphomatous polyposis of the gut: case report.

Multiple lymphomatous polyposis (MLP) is an uncommon type of primary non-Hodgkin's gastrointestinal B-cell lymphoma characterized by the presence of multiple lymphomatous polyps along the gut. We present a patient with MLP in which the involvement was unusually widespread. The diagnosis was confirmed by the typical polyposis lesion, histology, phenotyping and clinical presentations. A 68-year-old man had a large mass at the ileocecal valve as well as multiple polyps along the whole digestive tract. At the time of diagnosis, lymphoma had involved bone marrow, peripheral blood, spleen, prostate and peripheral lymph nodes. The patient received 8 courses of chemotherapy with no remission. He died of pneumonia 11 months after diagnosis. Clinically, the diagnosis may be confused with epithelial polyps; and histologically, the diagnosis must be distinguished from benign lymphoid proliferations as well as other types of lymphoma. The prognosis for patients with MLP is relatively poor (the median survival is usually less than 3 years).

Management of lactose maldigestion by consuming milk containing lactobacilli.

The influence of nonfermented milk containing L. acidophilus or L. bulgaricus on lactose utilization by lactose maldigesters was investigated. Nonfermented milks containing L. acidophilus or L. bulgaricus at 10(8) and 10(9) CFU/ml were prepared using 2% low-fat milk. Lactose maldigestion was monitored by measuring breath hydrogen at hourly intervals for 8 hr following consumption of 400 ml of each diet. Nonfermented milk containing L. acidophilus B at 10(8) CFU/ml were not effective in reducing breath hydrogen and symptoms. Nonfermented milk containing L. acidophilus B at 10(9) CFU/ml only slightly decreased breath hydrogen production; however, the symptoms were significantly improved. Nonfermented milks containing L. bulgaricus 449 at 10(8) and 10(9) CFU/ml were effective in reducing breath hydrogen and symptoms. The results for bulgaricus milk were all significant. In this study, L. acidophilus B and L. bulgaricus 449 were chosen because of their similar beta-galactosidase activity and bile sensitivity. L. acidophilus and L. bulgaricus are both thermophilic lactobacilli and an active transport (permease) system is found in both species for lactose transport. The major factor affecting in vivo lactose digestion in this study appears to be the bacterial cell wall/membrane structures. That the cell wall/membrane structures of L. acidophilus are different from those of L. bulgaricus can be indirectly proven by the results of sonication time for maximum beta-galactosidase activity measurement. The results of this study indicate that L. bulgaricus is usually a better choice than L. acidophilus for manufacturing nonfermented milks for lactose maldigesters.