Evaluation of the frequency and factors predictive of hernia incarceration following transjugular intrahepatic portosystemic shunt placement

AIM

To examine the frequency and predictive factors for bowel incarceration following transjugular intrahepatic portosystemic shunts (TIPS) placement to treat refractory cirrhosis-induced ascites.

MATERIALS AND METHODS

Ninety-nine patients with known hernias at the time of TIPS placement were identified. Their electronic medical records were reviewed and pertinent pre-procedural, procedural, and outcome variables were recorded. Patients were divided between those that suffered incarceration (study group) and a control group of those with a hernia who did not suffer incarceration.

RESULTS

Twelve of the 99 patients (12.1%) suffered hernia incarceration, of which seven (7.1%) suffered incarceration in the first 90 days. One patient who suffered incarceration ultimately died from complications of the incarceration. When comparing all patients who suffered incarceration to controls, incarceration patients were found to have significantly higher albumin levels (mean 3.13 versus 2.73, p=0.02). When just considering those who had incarcerations in the first 90 days to controls, incarceration patients were less likely to have improvement in their ascites (p=0.04).

CONCLUSIONS

Incarcerated hernias occur frequently after TIPS placement and can lead to significant morbidity and mortality. Clinicians should be aware of this complication and counsel patients on presenting symptoms prior to placement.

Isolation and Identification of Streptomyces spp. from Desert and Savanna Soils in Sudan

The purpose of this study was to investigate streptomycete populations in desert and savanna ecozones in Sudan and to identify species based on 16S rRNA gene sequences. A total of 49 different Streptomyces phenotypes (22 from sites representing the desert and semi-desert ecozone; 27 representing the savanna ecozone) have been included in the study. The isolates were characterized phenotypically and confirmed using 16S rRNA gene sequence analysis. The two ecozones showed both similarities and uniqueness in the types of isolates. The shared species were in cluster 1 (Streptomyces (S.) werraensis), cluster 2 (Streptomyces sp.), cluster 3 (S. griseomycini-like), and cluster 7 (S. rochei). The desert ecozone revealed unique species in cluster 9 (Streptomyces sp.) and cluster 10 (S. griseomycini). Whereas, the savanna ecozone revealed unique species in cluster 4 (Streptomyces sp.), cluster 5 (S. albogriseolus/ S. griseoincarnatus), cluster 6 (S. djakartensis), and cluster 8 (Streptomyces sp.). Streptomycetes are widely distributed in both desert and the savanna ecozones and many of these require full descriptions. Extending knowledge on Streptomyces communities and their dynamics in different ecological zones and their potential antibiotic production is needed.

Diversity and geographic distribution of soil streptomycetes with antagonistic potential against actinomycetoma-causing Streptomyces sudanensis in Sudan and South Sudan

BACKGROUND

Production of antibiotics to inhibit competitors affects soil microbial community composition and contributes to disease suppression. In this work, we characterized whether Streptomyces bacteria, prolific antibiotics producers, inhibit a soil borne human pathogenic microorganism, Streptomyces sudanensis. S. sudanensis represents the major causal agent of actinomycetoma - a largely under-studied and dreadful subcutaneous disease of humans in the tropics and subtropics. The objective of this study was to evaluate the in vitro S. sudanensis inhibitory potential of soil streptomycetes isolated from different sites in Sudan, including areas with frequent (mycetoma belt) and rare actinomycetoma cases of illness.

RESULTS

Using selective media, 173 Streptomyces isolates were recovered from 17 sites representing three ecoregions and different vegetation and ecological subdivisions in Sudan. In total, 115 strains of the 173 (66.5%) displayed antagonism against S. sudanensis with different levels of inhibition. Strains isolated from the South Saharan steppe and woodlands ecoregion (Northern Sudan) exhibited higher inhibitory potential than those strains isolated from the East Sudanian savanna ecoregion located in the south and southeastern Sudan, or the strains isolated from the Sahelian Acacia savanna ecoregion located in central and western Sudan. According to 16S rRNA gene sequence analysis, isolates were predominantly related to Streptomyces werraensis, S. enissocaesilis, S. griseostramineus and S. prasinosporus. Three clusters of isolates were related to strains that have previously been isolated from human and animal actinomycetoma cases: SD524 (Streptomyces sp. subclade 6), SD528 (Streptomyces griseostramineus) and SD552 (Streptomyces werraensis).

CONCLUSION

The in vitro inhibitory potential against S. sudanensis was proven for more than half of the soil streptomycetes isolates in this study and this potential may contribute to suppressing the abundance and virulence of S. sudanensis. The streptomycetes isolated from the mycetoma free South Saharan steppe ecoregion show the highest average inhibitory potential. Further analyses suggest that mainly soil properties and rainfall modulate the structure and function of Streptomyces species, including their antagonistic activity against S. sudanensis.

Beta amino acid-modified and fluorescently labelled kisspeptin analogues with potent KISS1R activity

Kisspeptin analogues with improved metabolic stability may represent important ligands in the study of the kisspeptin/KISS1R system and have therapeutic potential. In this paper we assess the activity of known and novel kisspeptin analogues utilising a dual luciferase reporter assay in KISS1R-transfected HEK293T cells. In general terms the results reflect the outcomes of other assay formats and a number of potent agonists were identified among the analogues, including β(2) -hTyr-modified and fluorescently labelled forms. We also showed, by assaying kisspeptin in the presence of protease inhibitors, that proteolysis of kisspeptin activity within the reporter assay itself may diminish the agonist outputs. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd.

Calcium-lowering action of glucocorticoids in adrenalectomized-parathyroidectomized rats. Specificity and relative potency of natural and synthetic glucocorticoids

The specificity and potency of glucocorticoids to lower serum calcium (Ca) in rats after parathyroidectomy (PTX) and adrenalectomy (ADX) were examined. Rats fasted overnight were given sc injections of various steroids immediately after the operations. The fall in serum calcium 5 h after PTX-ADX in rats given hypocalcemic doses of corticosterone was compared to that after injection of a test steroid. At high doses, progesterone, estradiol, testosterone, and aldosterone were inactive, whereas glucocorticoids were consistently hypocalcemic. These results indicate that the Ca-lowering effect is specific for steroids with glucocorticoid activity. Potency estimates were made by comparing the dose-response of natural and synthetic glucocorticoids to that of corticosterone, the major glucocorticoid in rats. The mean potency of hydrocortisone was 8.2 times that of corticosterone. Prednisolone was about 9.6, triamcinolone 33, betamethasone 109, and dexamethasone 301 times as potent as corticosterone. Thus, the use of the calcium-lowering action as a bioassay has provides a specific and rapid in vivo method to compare potencies of glucocorticoids consistent with those obtained by anti-inflammatory and glycogen deposition assays. The importance of this interesting calcitonin-like action of glucocorticoids in normal physiology of calcium metabolism is not yet established.

Hypocalcemic effect of physiological concentrations of corticosterone in adrenalectomized-parathyroidectomized rats

We have confirmed the serum calcium-raising effect of adrenalectomy in young male rats 5-6 h after parathyroidectomy that was first observed by others many years ago. (The phenomenon has also been reported in cats, dogs, and mice.) In addition, we have shown that adrenalectomy raises the serum ionized calcium as well as total calcium and that the effect occurs in young female as well as in young male rats. Furthermore, we have found that the serum calcium-raising effect of adrenalectomy occurs if the adrenalectomy is performed several days before parathyroidectomy or 6 h after parathyroidectomy, as well as at the same time as the parathyroidectomy. When the rats were adrenalectomized 7-9 days before parathyroidectomy and given small daily life-maintaining doses of corticosterone or cortisone acetate, this glucocorticoid treatment did not reverse the adrenalectomy effect. This led us to think at first that the effect of adrenalectomy must be due to the loss of an unknown adrenal factor rather than to loss of glucocorticoid. Additional experiments, however, in which corticosterone or hydrocortisone was administered by continuous release pellets, demonstrated conclusively that a small continuous supply of corticosterone (within the physiological range as determined by immunoassay of plasma) was sufficient to reverse the adrenalectomy effect. The results with hydrocortisone were similar at even lower doses than of corticosterone. Somewhat higher doses of corticosterone or hydrocortisone reduced the serum calcium even below the parathyroidectomy level. In a preliminary investigation of the specificity of the glucocorticoid effect we found that aldosterone, dehydroepiandrosterone, or estradiol had no effect on serum calcium under similar conditions. We conclude that the fall in serum calcium after parathyroidectomy in rats is due in part to the hypocalcemic effect of endogenous corticosterone. Thus, the loss of corticosterone after adrenalectomy explains the serum calcium-raising effect of adrenalectomy in parathyroidectomized rats. These results also suggest that glucocorticoids at physiological levels have a significant effect on calcium metabolism in general.

Role of Na+/K+-stimulated adenosine triphosphatase in the action of dopaminergic-D2 receptors of the liver in rats

The dopamine receptor agonist, bromocriptine, in a dose of 10 mg/kg i.p. for 14 days, in rats caused a significant increase in liver Na+/K+-ATPase activity, whereas sulpiride, a dopamine receptor antagonist, in a dose of 10 mg/kg, i.p. for 14 days, in rats, caused a significant decrease in liver Na+/K+-ATPase activity. Injection of bromocriptine and sulpiride simultaneously in a group of rats, under the same conditions and using the same doses caused a complete block of both stimulatory activity of bromocriptine and inhibitory activity of sulpiride on liver Na+/K+-ATPase activity. It is suggested that Na+/K+-ATPase may have a role in the action of dopaminergic-D2 receptors.

Effects of calcium and (inorganic) phosphate on bone resorption produced by vitamin D3 metabolites in vitro

The effects of changing the concentrations of calcium (Ca2+) and inorganic phosphate (Pi) on 45Ca release from prelabeled fetal rat bones caused by parathyroid hormone (PTH), 25-hydroxyvitamin D3 (25-OH-D3) and 1, 25-dihydroxyvitamin D3 (1,25-(OH)2-D3) were tested, in vitro. Increasing total (Ca2+) from 1.25 mM to 2.5 mM caused a significant increase in bone resorption caused by submaximal concentrations of these materials. Further increase in total (Ca2+) to 3.5 mM abolished this potentiating effect of bone resorption. Increasing the (Pi) from 1 mM to 2-3 mM caused significant inhibition of bone resorption caused by these resorbing materials. In addition, a (Pi) of 3 mM caused significant inhibition of higher concentrations of PTH and 25-OH-D3. (Pi) of 2 and 3 mM also caused significant inhibition of 45Ca release from control bones. It is concluded that a moderate increase in medium (Ca2+) mimics the effect of these bone resorbing materials on bone. Phosphate appears to be a direct inhibitor of bone resorption. Therefore, changing the (Ca2+) and (Pi) in the medium can affect the bone resorbing effect of vitamin D3 metabolites, similar to their effect on PTH.

Some observations on the oxidation phenotype status of Nigerian patients presenting with cancer

The hypothesis is being explored that there may be an association between genetically determined oxidation status and propensity to develop carcinoma in response to environmental chemical carcinogens. For this purpose, the genetic structure of a normal, healthy Nigerian population with respect to oxidation status, has been compared with that found for a group of 59 Nigerian patients presenting with carcinoma of the liver and gastrointestinal tract. Genetically determined oxidation status was assessed by measuring the extent of oxidation of a probe drug, debrisoquine, to its major metabolite, 4-hydroxydebrisoquine. The cancer group contained a disproportionately large number of individuals who were extensive oxidizers compared to the controls (2 P = 0.0045). The findings support the view that genetically determined oxidation status may be an important host factor in influencing responsiveness to chemical carcinogens that require oxidative metabolic activation.

Interaction between 24R,25-dihydroxycholecalciferol and 1,25-dihydroxycholecalciferol on 45Ca release from bone in vitro

Interaction among vitamin D3 metabolites on bone receptor sites is not known. Therefore, interaction between the most potent vitamin D3 metabolite, 1,25(OH)2D3, and the most abundant dihydroxymetabolite, 24R,25(OH)2D3, was studied on isolated rat fetal bone by measuring 45Ca release from prelabeled bones. 24R,25(OH)2D3 at concentrations of 10-50 ng/ml caused marked inhibition of the bone-resorbing activity of 1,25(OH)2D3 at concentrations of 10-50 pg/ml. 24S,25(OH)2 (unnatural enantiometer), on the other hand, at a concentration of 100 ng/ml did not inhibit the bone-resorbing effect of 10 pg/ml 1,25(OH)2D3. 24R,25(OH)2D3 at a concentration of 20 ng/ml did not inhibit the 45Ca-releasing effect of a submaximal concentration of PTH (500 ng/ml). Therefore, the inhibitory effect of 24R,25(OH)2D3 on the bone response to 1,25(OH)2D3 appeared to be specific and probably due to a competitive inhibitory effect. In addition, the inhibitory effect of 24R,25(OH)2D3 was weak, since it could be partially overcome by increasing the concentration of 1,25(OH)2D3.

A study of the debrisoquine hydroxylation polymorphism in a Nigerian population

1. The metabolic oxidation of debrisoquine has been studied in a group of 123 Nigerian volunteers. 2. All subjects excreted unchanged drug together with five oxidation products, namely, 4-, 5-, 6-, 7- and 8-hydroxy-debrisoquine. 3. The 4-hydroxylation reaction exhibits polymorphism; ten subjects were defective in their ability to effect this reaction. 4. The incidence (q) of the allele governing impaired 4-hydroxylation (DL) among Nigerians was calculated as being 0.28 (95% confidence limit of 0.20-0.37). 5. An association was demonstrated between the ability to effect 4-hydroxylation and 6- and 7-hydroxylation of debrisoquine, suggesting that the alleles controlling alicyclic oxidation also influence aromatic hydroxylation.

A family and population study of the genetic polymorphism of debrisoquine oxidation in a white British population

A population survey of 258 unrelated white British subjects showed a polymorphism for the 4-oxidation of debrisoquine. "Extensive metabolisers" (EM) and "poor metabolisers" (PM) are recognisable, 8.9% of the population being PM. Nine pedigrees ascertained through PM probands show that the PM phenotype is an autosomal Mendelian recessive character. The EM phenotype is dominant and the degree of dominance has been estimated at 30%. PM subjects are more prone to hypotension during debrisoquine therapy. The alleles controlling this polymorphism appear to control the oxidation of other drugs.

Debrisoquin hydroxylation polymorphism among Ghanaians and Caucasians

The alicyclic and aromatic hydroxylation of debrisoquin was studied in Ghanaians. As in a previously studied Caucasian population, the alicyclic 4-hydroxylation of debrisoquin in Ghanaians was polymorphic. Three phenotypes were observed: homozygous extensive metabolizers (58%), heterozygous extensive metabolizers (36%), and homozygous poor metabolizers (6%). In contrast, British Caucasians are primarily monomorphic extensive metabolizers (92%) and homozygous poor metabolizers comprise 8% of the population. Urinary recovery of the drug and its hydroxylated metabolites was significantly less in the Ghanaian subjects. In both Ghanaian and British populations, aromatic hydroxylation producing 5-, 6-, 7-, and 8-hydroxydebrisoquin was shown to parallel the alicyclic 4-hydroxylation of debrisoquin, and thus to be controlled by the same gene locus. Debrisoquin is advocated as a tool for uncovering polymorphism in drug oxidation and its interethnic variations.

The metabolism of [14C]-debrisoquine in man

1 The synthesis of [14C]-debrisoquine hydrochloride and 4-hydroxy-debrisoquine sulphate is described. 2 The metabolic fate and excretion profile in both urine and faeces of 14C-labelled debrisoquine was studied in five healthy human subjects. 3 Investigations showed that the drug is well-absorbed after a single oral dose of 32 mg and quantitatively eliminated from the body within three days. 4 4-Hydroxy-debrisoquine is the major metabolite of debrisoquine, although significant amounts of 5-,6-, 7- and 8-hydroxy-debrisoquine are also formed. 5 Electron-capture gas chromatography is a useful method for measuring debrisoquine and its five hydroxylated metabolites in urine at the pg level.

A population and familial study of the defective alicyclic hydroxylation of debrisoquine among Egyptians

1. Debrisoquine hydroxylation exhibited profound variation in 72 Egyptian volunteers. 2. The frequency distribution histogram of the metabolic ratio (ratio unchanged drug: 4-hydroxy metabolite in 0-8 h urine) was polymodal. 3. From family data it was possible to define more clearly than before the heterozygous characteristics. 4. Egyptians appear in general to be more extensive oxidizers of debrisoquine than do English subjects. 5. Ramadan fasting was found to lower the absorption of debrisoquine.

Polymorphism of carbon oxidation of drugs and clinical implications

Eight volunteers previously phenotyped for their ability to hydroxylate debrisoquine (four extensive metabolisers (EM), four poor metabolisers (PM) were investigated for their metabolic handling of guanoxan and phenacetin. All three drugs are oxidised at carbon centres. Oxidative dealkylation of phenacetin was determined by measuring the rate of formation of paracetamol. The EM subjects excreted mostly metabolites of guanoxan (mean 29% of dose), whereas the PM group excreted large amounts of unchanged drug (48% of dose). The rate of formation of paracetamol was noticeably slower in the PM group, and, when analysed by minimum estimates of apparent first-order rate constants, the difference between the two phenotypes was significant. Thus the hydroxylation defect shown for debrisoquine metabolism carries over to the oxidative metabolism of phenacetin and guanoxan. Some 5% of the population are genetically defective hydroxylators of drugs. Thus methods for evaluating the metabolism of new drugs in respect of usage and side effects need to be revised.

Polymorphic hydroxylation of Debrisoquine in man

Debrisoquine and its primary metabolite, 4-hydroxydebrisoquine, were measured in the urine of 94 volunteers after a single oral dose of 10 mg debrisoquine. The ratio between excreted debrisoquine and its metabolite was bimorphically distributed in the study population. Family studies supported the view that alicyclic 4-hydroxylation of debrisoquine is controlled by a single autosomal gene and that a defect in this metabolic step is caused by a recessive allele.

Effect of hydroxy-vitamin D3 derivatives on 45Ca release from rat fetal bones in vitro

Several hydroxy vitamin D3 (OH-D3) derivatives were tested for biological activity by measuring 45Ca release from prelabeled rat fetal bones, in vitro. In a 72 h continuous culture, 1 alpha,25-(OH)2-D3 produced a significant effect at 10 pg/ml. A similar effect was produced by 50 ng/ml of either 25-OH-D3 or 5,6-trans-25-OH-D3, and by 500 pg of 3 deoxy-1 alpha,25-(OH)2-D3. 24R,25-(OH)2-D3 was more active than 24S,25-(OH)2-D3, and the R isomer had activity that more closely resembled the biosynthetic compound. 3-deoxy-1 alpha-OH-D3 was inactive at a concentration of up to 1 microgram/ml. Using a 24 h preincubation period with no added vitamin D3 derivative, a steep dose-response curve could be obtained with 1 alpha,25-(OH)2-D3 over a range of 2-10 pg/ml during a subsequent 96 h incubation period, and 1 alpha,25-(OH)2-D3 was found to have about 5000 times the activity of 25-OH-D3.