Lactose Intolerance—Old and New Knowledge on Pathophysiological Mechanisms, Diagnosis, and Treatment

Lactose intolerance is a pathology frequently encountered today. It occurs when the activity of lactase in the intestine is reduced or absent, with consequent failure to digest lactose. The global prevalence of this clinical condition is estimated of about 57% with instrumental methods, while the real prevalence exceeds 65%. The absence of lactase determines both the excessive osmotic load in the small intestine and the fermentation of lactose by the bacterial flora with consequent production of short-chain fatty acids and gas. This latter process is responsible for the onset of symptoms associated with lactose intolerance (abdominal pain, bloating, flatulence, etc.) which arise after the intake of lactose. Several studies have shown an increased risk of developing various pathologies for lactose-intolerant subjects (some types of cancer, osteoporosis, etc.). Therefore, it is essential to diagnose and properly treat this pathology. Various options exist for diagnosing lactose intolerance: Hydrogen Breath Test, genetic test, Quick Lactose Intolerant Test, Lactose Tolerance Test, Gaxilose Test. Like diagnostic methods, there are several options for treating intolerance. In addition to a food restriction, the use of exogenous enzymes and/or probiotic and the selection of milk containing specific types of beta-caseins less correlated to the appearance of gastrointestinal symptoms are very useful. The aim of this review is to illustrate the main and most modern diagnostic and therapeutic choices for lactose intolerance currently available.

Fructose and irritable bowel syndrome

Irritable bowel syndrome (IBS) is a chronic disorder characterised by recurrent abdominal pain or discomfort and transit disturbances with heterogeneous pathophysiological mechanisms. The link between food and gastrointestinal (GI) symptoms is often reported by patients with IBS and the role of fructose has recently been highlighted. Fructose malabsorption can easily be assessed by hydrogen and/or methane breath test in response to 25 g fructose; and its prevalence is about 22 % in patients with IBS. The mechanism of fructose-related symptoms is incompletely understood. Osmotic load, fermentation and visceral hypersensitivity are likely to participate in GI symptoms in the IBS population and may be triggered or worsened by fructose. A low-fructose diet could be integrated in the overall treatment strategy, but its role and implication in the improvement of IBS symptoms should be evaluated. In the present review, we discuss fructose malabsorption in adult patients with IBS and the interest of a low-fructose diet in order to underline the important role of fructose in IBS.

Postprandial effects on electrolyte homeostasis in the kidney

Insulin is known to be an important regulator of a number of different channels and transporters in the kidney, but its role in the kidney to prevent Na+ and volume loss during the osmotic load after a meal has only recently been validated. With increasing numbers of people suffering from diabetes and hypertension, furthering our understanding of insulin signaling and renal Na+ handling in both normal and diseased states is essential for improving patient treatments and outcomes. The present review is focused on postprandial effects on Na+ reabsorption in the kidney and the role of the epithelial Na+ channels as an important channel contributing to insulin-mediated Na+ reclamation.

Penentuan pH optimum untuk pertumbuhan kepiting bakau Scylla serrata dalam wadah terkontrol

<p class="NoParagraphStyle"><strong>ABSTRACT</strong><strong></strong></p><p class="NoParagraphStyle"> </p><p class="NoParagraphStyle">One of the abiotic factors that affects the growth and the survival of crabs is pH. The optimum pH media will give maximum impact on mangrove crabs because it is related with the osmoregulation process. This study aimed to examine the effect of pH on the survival rate (SR) and specific growth rate (SGR) of mangrove crab <em>Scylla serrata</em> through the reaction of physiological condition. This study consisted of the treatments with the pH medium 5 (A), pH medium 6 (B), pH medium 7 (C), and pH medium 8 (D). The crab’s maintenance in different pH gave a significant effect (P&lt;0.05) on the survival rate of the crabs. The pH treatments also gave a significant effect (P&lt;0.05) on the SGR of the crabs. The low level of crab stress at pH 7 was described by the total value of high hemocyte and the high osmotic load so that the pH 7 was the optimum condition for the crabs.</p><p class="NoParagraphStyle"> </p><p class="NoParagraphStyle">Keywords: pH, survival, specific growth rate, mangrove crabs</p><p class="NoParagraphStyle"> </p><p class="NoParagraphStyle"> </p><p class="NoParagraphStyle"><strong>ABSTRAK</strong><strong></strong></p><p class="NoParagraphStyle"> </p><p class="NoParagraphStyle">Salah satu faktor abiotik yang mempengaruhi pertumbuhan dan kelangsungan hidup kepiting adalah pH. Media pH optimum akan memberikan dampak maksimum pada kepiting bakau karena terkait dengan proses osmoregulasi. Penelitian ini bertujuan untuk menguji pengaruh pH pada tingkat kelangsungan hidup (SR) dan laju pertumbuhan spesifik (SGR) kepiting mangrove <em>Scylla serrata</em> melalui reaksi kondisi fisiologis. Penelitian ini terdiri atas perlakuan dengan media pH 5 (A), sedang pH 6 (B), sedang pH 7 (C), dan menengah pH 8 (D). Pemeliharaan kepiting di pH yang berbeda memberikan pengaruh yang signifikan (P&lt;0,05) pada tingkat kelangsungan hidup kepiting. Perlakuan pH juga memberikan efek yang signifikan (P&lt;0,05) pada SGR dari kepiting. Rendahnya tingkat stres kepiting pada pH 7 digambarkan oleh nilai total hemosit tinggi dan beban osmotik tinggi sehingga pH 7 adalah kondisi optimum untuk kepiting.</p><p class="NoParagraphStyle"> </p><p>Kata kunci: pH, kelangsungan hidup, laju pertumbuhan spesifik, kepiting mangrove</p>

The physiology and mechanics of undulatory swimming: a student laboratory exercise using medicinal leeches

The medicinal leech is a useful animal model for investigating undulatory swimming in the classroom. Unlike many swimming organisms, its swimming performance can be quantified without specialized equipment. A large blood meal alters swimming behavior in a way that can be used to generate a discussion of the hydrodynamics of swimming, muscle mechanics, hydrostatic skeletons, and the physiological features that allow leeches to deal with the volume increase and osmotic load imposed by the meal. Analyses can be carried out at a range of levels tailored to suit a particular class.

Safety of Oral Sulfates in Rats and Dogs Contrasted With Phosphate-Induced Nephropathy in Rats

An oral sulfate salt solution (OSS), under development as a bowel cleansing agent for colonoscopy in humans, is studied in rats and dogs. In rats, amaximumpractical oral OSS dose (5 g/kg/d) is compared with an oral sodium phosphate (OSP) solution, both at about 7 times the clinical dose. OSS induces the intended effects of loose stools and diarrhea. In rats, higher urine sodium and potassium accompany higher clearance rates, considered adaptive to the osmotic load of OSS. OSS for 28 days is well tolerated in rats and dogs. In contrast, OSP causes increased mortality, reduced body weight and food consumption, severe kidney tubular degeneration, and calcium phosphate deposition in rats. These are accompanied by mineralization in the stomach and aorta, along with cardiac and hepatic degeneration and necrosis. The greater safety margin of OSS over OSP at similarmultiples of the clinical dose indicates its suitability for human use.

Beneficial effect of taurine depletion on osmotic sodium and calcium loading during chemical hypoxia

Cellular sodium excess is cytotoxic because it increases both the intracellular osmotic load and intracellular calcium concentration ([Ca2+]i). Because sodium levels rise during hypoxia, it is thought to contribute to hypoxic injury. Thus the present study tested the hypothesis that taurine-linked reductions in [Na+]i reduce hypoxia-induced cell injury. Taurine depletion was achieved by exposing isolated neonatal cardiomyocytes to medium containing the taurine analog β-Alanine. As predicted, the β-Alanine-treated cell exhibited less hypoxia-induced necrosis and apoptosis than the control, as evidenced by less swelling, shrinkage, TdT-mediated dUTP nick end labeling staining, and accumulation of trypan blue. After 1 h of chemical hypoxia, [Na+]i was 3.5-fold greater in the control than the taurine-deficient cell. Although more taurine was lost from the control cell than from the β-Alanine-treated cell during hypoxia, the combined taurine and sodium osmotic load was lower in the β-Alanine-treated cell. Taurine deficiency also reduced the degree of hypoxia-induced calcium overload. Thus the observed resistance against hypoxia-induced necrosis and apoptosis is probably related to an improvement in sodium and calcium handling.