Search

Describes a study that measured blood glucose during symptomatic episodes in 28 patients with suspected postprandial hypoglycemia. Details of study; Results; Conclusions.

Dynamic changes in maternal‒zygotic transition (MZT) require complex regulation of zygote formation, maternal transcript decay, embryonic genome activation (EGA), and cell cycle progression. Although these changes are well described, some key regulatory factors are still elusive. Sirtuin-1 (SIRT1), an NAD + -dependent histone deacetylase, is a versatile driver of MZT via its epigenetic and nonepigenetic substrates. This study focused on the dynamics of SIRT1 in early embryos and its contribution to MZT. A conditional SIRT1-deficient knockout mouse model was used, accompanied by porcine and human embryos. Embryos across mammalian species showed the prominent localization of SIRT1 in the nucleus throughout early embryonic development. Accordingly, SIRT1 interacts with histone H4 on lysine K16 (H4K16) in both mouse and human blastocysts. While maternal SIRT1 is dispensable for MZT, at least one allele of embryonic Sirt1 is required for early embryonic development around the time of EGA. This role of SIRT1 is surprisingly mediated via a transcription-independent mode of action., (© 2024. The Author(s).)

Despite the advances in the treatment of rheumatoid arthritis (RA) achieved in the last few years, several patients are diagnosed late, do not respond to or have to stop therapy because of inefficacy and/or toxicity, leaving still a huge unmet need. Tissue-specific strategies have the potential to address some of these issues. The aim of the study is the development of a safe nanotechnology approach for tissue-specific delivery of drugs and diagnostic probes. CD34  +  endothelial precursors were addressed in inflamed synovium using targeted biodegradable nanoparticles (tBNPs). These nanostructures were made of poly-lactic acid, poly-caprolactone, and PEG and then coated with a synovial homing peptide. Immunofluorescence analysis clearly demonstrated their capacity to selectively address CD34  +  endothelial cells in synovial tissue obtained from human, mouse, and rat. Biodistribution studies in two different animal models of rheumatoid arthritis (antigen-induced arthritis/AIA and collagen-induced arthritis/CIA) confirmed the selective accumulation in inflamed joints but also evidenced the capacity of tBNP to detect early phases of the disease and the preferential liver elimination. The therapeutic effect of methotrexate (MTX)-loaded tBNPs were studied in comparison with conventional MTX doses. MTX-loaded tBNPs prevented and treated CIA and AIA at a lower dose and reduced administration frequency than MTX. Moreover, MTX-loaded tBNP showed a novel mechanism of action, in which the particles target and kill CD34  +  endothelial progenitors, preventing neo-angiogenesis and, consequently, synovial inflammation. tBNPs represent a stable and safe platform to develop highly-sensitive imaging and therapeutic approaches in RA targeting specifically synovial neo-angiogenesis to reduce local inflammation., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

AKR1B10 is an NADPH-dependent reductase that plays an important function in several physiological reactions such as the conversion of retinal to retinol, reduction of isoprenyl aldehydes, and biotransformation of procarcinogens and drugs. A growing body of evidence points to the important role of the enzyme in the development of several types of cancer (e.g., breast, hepatocellular), in which it is highly overexpressed. AKR1B10 is regarded as a therapeutic target for the treatment of these diseases, and potent and specific inhibitors may be promising therapeutic agents. Several inhibitors of AKR1B10 have been described, but the area of natural plant products has been investigated sparingly. In the present study almost 40 diverse phenolic compounds and alkaloids were examined for their ability to inhibit the recombinant AKR1B10 enzyme. The most potent inhibitors-apigenin, luteolin, and 7-hydroxyflavone-were further characterized in terms of IC50, selectivity, and mode of action. Molecular docking studies were also conducted, which identified putative binding residues important for the interaction. In addition, cellular studies demonstrated a significant inhibition of the AKR1B10-mediated reduction of daunorubicin in intact cells by these inhibitors without a considerable cytotoxic effect. Although these compounds are moderately potent and selective inhibitors of AKR1B10, they constitute a new structural type of AKR1B10 inhibitor and may serve as a template for the development of better inhibitors.

Paclitaxel (PTX), docetaxel (DTX), 5-fluorouracil (5-FU), cyclophosphamide (CYC) or tamoxifen (TMX) are combined with doxorubicin (DOX) in first-line chemotherapy regimens that are indicated for breast cancer patients. Although the efficacies of these drugs in combination treatments have been demonstrated in clinical practice, their possible interference with DOX metabolism has not been described in detail to date. In the present study, we investigated the possible interactions of human carbonyl reducing enzymes with 5-FU, PTX, DTX, CYC and TMX. First, the reducing activities of carbonyl reducing enzymes toward DOX were tested using incubations with purified recombinant enzymes. In the subsequent studies, we investigated the possible effects of the tested anticancer agents on the DOX-reducing activities of the most potent enzymes (AKR1C3, CBR1 and AKR1A1) and on the DOX metabolism driven by MCF7, HepG2 and human liver cytosols. In both of these assays, we observed that CYC and its active metabolites inhibited DOX metabolism. In the final study, we tracked the changes in AKR1C3, CBR1 and AKR1A1 expression levels following exposure to the tested cytostatics in MCF7 and HepG2 cells. Consequently, no significant changes in the expression levels of tested enzymes were detected in either cell line. Based on these findings, it is feasible to presume that inhibition rather than induction plays a role in the interactions of the tested anticancer agents with DOX-reducing enzymes. In conclusion, our results describe important molecular events that occur during combination breast cancer therapies and might modulate pharmacokinetic DOX resistance and/or behaviour., (Copyright © 2015 Elsevier Inc. All rights reserved.)

AKR1C3 is an important human enzyme that participates in the reduction of steroids and prostaglandins, which leads to proliferative signalling. In addition, this enzyme also participates in the biotransformation of xenobiotics, such as drugs and procarcinogens. AKR1C3 is involved in the development of both hormone-dependent and hormone-independent cancers and was recently demonstrated to confer cell resistance to anthracyclines. Because AKR1C3 is frequently upregulated in various cancers, this enzyme has been suggested as a therapeutic target for the treatment of these pathological conditions. In this study, nineteen isoquinoline alkaloids were examined for their ability to inhibit a recombinant AKR1C3 enzyme. As a result, stylopine was demonstrated to be the most potent inhibitor among the tested compounds and exhibited moderate selectivity towards AKR1C3. In the follow-up cellular studies, stylopine significantly inhibited the AKR1C3-mediated reduction of daunorubicin in intact cells without considerable cytotoxic effects. This inhibitor could therefore be used as a model AKR1C3 inhibitor in research or evaluated as a possible therapeutic anticancer drug. Furthermore, based on our results, stylopine can serve as a model compound for the design and future development of structurally related AKR1C3 inhibitors., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Diabetic ketoacidosis and the hyperglycemic hyperosmolar state are the most serious complications of diabetic decompensation and remain associated with excess mortality. Insulin deficiency is the main underlying abnormality. Associated with elevated levels of counterregulatory hormones, insulin deficiency can trigger hepatic glucose production and reduced glucose uptake, resulting in hyperglycemia, and can also stimulate lipolysis and ketogenesis, resulting in ketoacidosis. Both hyperglycemia and hyperketonemia will induce osmotic diuresis, which leads to dehydration. Clinical diagnosis is based on the finding of dehydration along with high capillary glucose levels with or without ketones in the urine or plasma. The diagnosis is confirmed by the blood pH, serum bicarbonate level and serum osmolality. Treatment consists of adequate correction of the dehydration, hyperglycemia, ketoacidosis and electrolyte deficits.

1,25-Dihydroxyvitamin D3 [1,25-(OH)2D3], the hormone of the vitamin D3 (D3) endocrine system, has been shown to influence malignant and normal cell proliferation/differentiation, while insulin (I) is known to be essential for liver growth. To investigate the influence of D3 on liver regeneration, the effect of the D status was studied in D-depleted rats (D-) pretreated with: G1, placebo (D-, hypocalcemic); G2, oral calcium only (D-, normocalcemic); G3, D3; and G4, 1,25-(OH)2D3. Two thirds hepatectomy (HX) or sham operation was performed, and regeneration was studied for 3 weeks. I response to glucose challenge and the hepatic I receptor were also studied. Cell volume, DNA, and RNA were not affected by pretreatment. After HX, the pattern of [3H]thymidine incorporation into DNA (P less than 0.003) and the cell labeling index (P less than 0.0001) were highly influenced by pretreatment and suggestive of an earlier appearance of the S phase of the cell cycle in the 1,25-(OH)2D3-treated compared to the D- hypocalcemic group. Furthermore, the mitotic index revealed a significant effect of pretreatment (P less than 0.01), with peak mitosis 24 h after HX in D3-treated and 1,25-(OH)2D3-treated rats compared to 30-36 h after HX in the D- groups. Liver weight restitution was impaired in D- rats (P less than 0.009) and is illustrated by the estimated time required to achieve 70% recovery of the resected liver mass, which was found to be 186 and 300 h in G1 and G2, and 154 and 107 h in G3 and G4. G1 rats had significantly higher glucose concentrations (fasting as well as after glucose injection) and reduced I secretion when challenged with glucose (P less than 0.001); they also had an upregulation in hepatic I receptor number (P less than 0.005) compared to calcium or D3-treated rats, while 1,25-(OH)2D3 led to a liver I receptor number similar to that found in hypocalcemic D- rats; the affinity of the I receptor was, however, only slightly changed by pretreatment (P less than 0.08). Our data indicate that in D depletion, hypocalcemia retards DNA synthesis and liver mass recovery, while normocalcemia contributes to DNA synthesis, but fails to sustain mitosis and compensatory liver growth to a level comparable to that found after D3 and/or 1,25-(OH)2D3 repletion. The observation that both D3 and 1,25-(OH)2D3 significantly promoted normal liver recovery after partial HX illustrates the role of the D endocrine system in normal cell physiology in vivo.

While insulin effects on the central nervous system (CNS) mediated through hypoglycaemia are well known, direct insulin effects on the CNS remain controversial. Recently, we found insulin receptors in all areas of the rat brain, with highest concentrations in the olfactory bulb, cerebral cortex and hypothalamus; all areas involved in feeding. Insulin receptors in brain were, by multiple criteria, similar to insulin receptors on classical target tissues for insulin, such as liver and fat. Insulin itself has been identified in the rat brain at concentrations on average ten times higher than in plasma. Highest concentrations were found in the olfactory bulb and hypothalamus. Brain insulin was indistinguishable from purified insulin by its behaviour in the radioimmunoassay, radioreceptor assay, bioassay and gel chromatography. In two experimental models representing extremes of plasma insulin concentrations (obese hyperinsulinaemic mice and diabetic insulinopenic rats) there were no significant changes in the concentration of insulin receptors in brain while liver receptors were modified in the expected way. This may reflect the protective influence of the blood-brain barrier on some special quality of brain insulin receptors. Insulin concentrations in brain were also unchanged in both models, which is probably indicative of the local synthesis of insulin. The role of insulin in the CNS is unknown. Besides well known metabolic actions of insulin, new roles can be postulated such as neurotransmission, neuromodulation and paracrine signalling.

In view of the potent influences of the central nervous system on glucose metabolism and on its hormonal regulators, and our recent finding of insulin and insulin receptors throughout the central nervous systsem, we have examined extreme conditions of hyperinsulinemia (obese mice) and hypoinsulinemia (streptozotocin-treated rats) with respect to changes in brain insulin and receptor content. Sprague-Dawley rats given streptozotocin (100 mg/kg body wt) developed severe diabetes and by 48 h showed no change in brain insulin. Rats given 65 mg/kg streptozotocin also had severe diabetes, but survived longer. Both at 7 d and at 30 d after streptozotocin treatment there was no significant change in brain insulin or in brain content of insulin receptors, despite the fact that peripheral hepatic receptors were elevated and pancreatic insulin was markedly depleted. The obese mice were studied at 8-10 wk when peripheral plasma insulin concentrations were 50-fold elevated and receptors on peripheral target cells were reduced to congruent with40-50% of normal; brain insulin concentrations and receptor content were indistinguishable from those of thin littermates. Thus, brain insulin, which is typically 10 times higher than plasma insulin concentrations, and brain receptor content, which is equivalent to receptor content on peripheral tissues, appears to be regulated entirely independently of hormone and receptor in the periphery. These findings are consistent with the hypothesis that insulin in the central nervous system is synthesized by the neural elements, and plays a role in the central nervous system which is unrelated to peripheral glucose metabolism.

33 cases of hyperthyroidism have been treated at "L'Hôpital Sainte-Justine" of Montréal, during the period 1961-1974. Nearly all patients were submitted to medical treatment. 15 were cured with medical treatment only, and 18 had to be submitted to a subtotal thyroidectomy. These two groups are compared and show the clear advantage of surgery in the treatment of this disease. There was no major post-operative complication. Two patients became definitively hypothyroid. The mean follow-up is five years and six months.

Despite total thyroidectomy, a patient with metastatic follicular carcinoma of the thyroid remained biologically euthyroid three months after stopping thyroxine (T4) therapy. Thyroid hormone production was investigated by means of a modified tri-iodothyronine (T3) suppression test, in which serum T4 was used as a suppression marker. After three weeks of oral T3 (Cytomel) therapy (50 micrograms/day), the serum T4 decreased from normal (108 nmol/L) to undetectable values. However, even though suppressive therapy was effective in preventing TSH dependent hormone secretion by the tumor, it did not prevent tumor growth and the eventual death of the patient.

Commercial sources provide good, though expensive antiinsulin antisera. We describe here a simple, fast and inexpensive method for the production of antiinsulin antisera. Purified pork insulin (Lente) was injected subcutaneously in oil/water/complete Freund adjuvant mixture. Three guinea pigs received 0.25 mg of insulin and three received 0.5 mg of insulin. Subsequent injections of the same dose were done 40 and 60 days later. Five animals developed antisera with titers superior to 1:10,000 40 days after the primary inoculation. Four out of five guinea pigs improved further their antibody titer after the 2nd and 3rd injection (p less than 0.0005). Good sensitivity was associated with titers superior to 1:50,000 and appeared only after the 2nd injection to improve further after the 3rd. Thus, four out of six animals developed antiinsulin antisera suitable for the radioimmunoassay (RIA). The antisera bound proinsulin on an equimolar basis with insulin while glucagon was not bound up to 100 ng/ml. The minimum detectable insulin concentration was about 12 pg (0.3 microU) at the optimum antiserum dilution. Six animals given a small dose of insulin (0.06 mg) developed antisera of a low titer and sensitivity, unsuitable for the RIA.

Sixty-three consecutive unselected patients with a solitary cold nodule of the thyroid were submitted to surgery. Prior to surgery they all had clinical evaluation and a fine-needle aspiration (FNA) biopsy of the nodule. Results of this study show that the FNA biopsy was correct in predicting cancer in 12 of 13 cancers for a sensitivity of 92%. When the nodule was benign, the FNA biopsy was right in 42 of the 50 benign nodules for a specificity of 84%. In comparison the clinical criteria alone were correct in suspecting only eight of the 13 cancers for a sensitivity of 62%, while correctly identifying 39 of the 50 benign nodules for a specificity of 72%. An association of the clinical criteria with the results of the FNA biopsy would have identified all the cancers in our group.

We have previously described a group of young females with virilization, acanthosis nigricans, insulin resistance, and markedly decreased binding of insulin to its receptor (syndrome of insulin resistance and acanthosis nigricans type A). The present report concerns a 15-yr-old female with clinical features indistinguishable from the type A patients, including virilization, acanthosis nigricans, and extreme resistance to endogenous and exogenous insulin. Insulin levels were 400-650 microU/ml while fasting and were over 2200 microU/ml when stimulated. Proinsulin was less than 10% of the total immunoassayable insulin. In distinct contrast to the type A patients, insulin receptors on cells from this patient were entirely normal on the basis of specificity, negative cooperativity, affinity, concentration, and interaction with antiinsulin receptor antibodies. These findings suggest the presence of an intracellular defect as the cause of the observed insulin resistance.