New insights into intestinal phages

The intestinal microbiota plays important roles in human health. This last decade, the viral fraction of the intestinal microbiota, composed essentially of phages that infect bacteria, received increasing attention. Numerous novel phage families have been discovered in parallel with the development of viral metagenomics. However, since the discovery of intestinal phages by d'Hérelle in 1917, our understanding of the impact of phages on gut microbiota structure remains scarce. Changes in viral community composition have been observed in several diseases. However, whether these changes reflect a direct involvement of phages in diseases etiology or simply result from modifications in bacterial composition is currently unknown. Here we present an overview of the current knowledge in intestinal phages, their identity, lifestyles, and their possible effects on the gut microbiota. We also gather the main data on phage interactions with the immune system, with a particular emphasis on recent findings.

Correction: New insights into intestinal phages

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Double Lumen Needle in Unipuncture Dialysis Type Double Headpump

Single needle dialysis is used as a method of vascular access in many European dialysis centres. However, recirculation has been incriminated as a disadvantage of this procedure. According to in vitro studies, recirculation should be limited to a minimum when using double lumen needles. The present study makes an in vivo comparison between single and double lumen needles in unipuncture (single needle) dialysis of the type double headpump (Bellco, BL 760) and studies the role of recirculation in dialysis performance. Although recirculation is significantly reduced with the double lumen needle, compared to the single lumen needle, the clearance of small molecules is not significantly different for both needle types.

A case of HELLP syndrome: an immuno-"logical" approach

We report on a 27-year-old woman who developed severe arterial hypertension on a background of general malaise within 48 hours after vaginal delivery, suggesting severe acute-onset pre-eclampsia. Concomitant biochemical observations of haemolysis, elevated liver tests and low platelets lead to the diagnosis of (post-partum) HELLP syndrome. Our patient was transferred immediately to the intensive care unit (ICU), where she underwent plasmapheresis in combination with intravenous glucocorticoids, nicardipine and labetalol. Our patient recovered fully after three plasmapheresis sessions. Genetic testing of mutations responsible for complement deficits was negative.

Study of the optimum ideal protein level for weaned piglets

The amount of ideal protein, represented by the first limiting valine (Val), for optimising the growth performances of weaned hybrid piglets was studied. Feeds were formulated based on the ideal protein concept and on a constant essential/nonessential amino acid (AA) ratio and net energy (NE) level. The animal performance trial was composed of five dietary treatments ranging from 0.57 to 0.81% calculated apparent (app.) ileal (il.) digestible (dig.) Val. The piglets, male and female in equal numbers (11 replicates x 6 piglets/pen x 5 treatments) entered the trial at about 4 weeks old (average live weight 8.1 kg). The piglets were a cross product of Piétrain sire x hybrid dam. Feed intake and weight were recorded every two weeks until the end of the trial at 10 weeks of age (average live weight 20.6 kg). The requirement was expressed in st. il. dig. AA-units, as this unit approaches available AA better than app. il. dig. AA. The standardised (st.) il. AA digestibility coefficients (DCAA) were determined for two feeds, close to the animal performance optima, in a digestion trial with four T-cannulated piglets of approximately 6 weeks old. The feed independent endogenous nitrogen excretion was measured with a protein-free feed; although this technique underestimates the actual endogenous N-losses, it provides a reasonable estimate of basal endogenous N-losses. The determined st. il. DCAA were lower than the calculated st. il. DCAA, based on the CVB (2000); this might be linked to the higher than expected crude fibre content of the experimental feeds. The Val-requirement necessary to optimise ADG and FCR was similar and amounted 0.70% st. il. dig. Val, which corresponded with a st. il. dig. Lys-level of 1.03%.

Genetic correction of sickle cell disease: insights using transgenic mouse models

Sickle cell disease is a hereditary disorder characterized by erythrocyte deformity due to hemoglobin polymerization. We assessed in vivo the potential curative threshold of fetal hemoglobin in the SAD transgenic mouse model of sickle cell disease using mating with mice expressing the human fetal Agamma-globin gene. With increasing levels of HbF, AgammaSAD mice showed considerable improvement in all hematologic parameters, morphopathologic features and life span/survival. We established the direct therapeutic effect of fetal hemoglobin on sickle cell disease and demonstrated correction by increasing fetal hemoglobin to about 9-16% in this mouse model. This in vivo study emphasizes the potential of the SAD mouse models for quantitative analysis of gene therapy approaches.

Long-term metabolic control by rat islet grafts depends on the composition of the implant

This study examines whether the loss of metabolic control in initially normalized islet transplants can result from the inadequate composition of the donor tissue. Streptozotocin-induced diabetic rats were followed for 64 weeks after the intraportal injection of islet isografts with different composition. The implantation of 2.3 million beta-cells (10(7)/kg body wt) as particles (>100 microm diameter) of primarily insulin-positive (70%) and glucagon-positive (20%) cells succeeded in a long-term normalization of 2-h fasting glycemia, glucose tolerance, and serum fructosamine. The same metabolic control was achieved in animals with short and long durations of diabetes or when grafts were implanted under the kidney capsule. At posttransplantation (PT) week 64, insulin reserves were 60% lower than those in age-matched controls, which may account for the glucose intolerance in a few old recipients. The same type of graft containing 0.7 million beta-cells (4 x 10(6)/kg body wt) corrected these metabolic parameters for more than 12 weeks; the proportionally lower insulin reserves were sufficient for the long-term correction of 2-h fasting glycemia, but did not avoid glucose intolerance in older recipients. When the higher beta-cells number (10(7)/kg body wt) was injected as smaller particles (<100 mpm diameter) of lower purity (55% insulin-positive) and negligible glucagon content (<5% glucagon-positive), the metabolic parameters were also corrected for 12 weeks PT but then progressively returned to overt diabetes (6 of 10) or glucose intolerance (4 of 10). We concluded that long-term metabolic normalization can be achieved by islet implants in the liver or under the kidney capsule. The loss of metabolic control in older animals can be caused by the inadequate composition of the graft, with the number of beta-cells, the proportion of other endocrine and nonendocrine cells, and the particle size as influential variables.

Hepatitis C virus in a hemodialysis unit: molecular evidence for nosocomial transmission

Between February 1991 and January 1992, elevated alanine aminotransferase (ALT) levels were observed in several hemodialysis patients in a dialysis center in Dendermonde, Belgium. By the end of 1992, 25 out of 68 patients had seroconverted for HCV antibodies. The HCV strains from 23 of these seroconverters were genotyped and classified as genotype 1b. Sequence analysis of the HCV Core region was carried out in 12 patients, 9 of whom were infected with a strain bearing a unique sequence motif as compared with the currently known HCV 1b strains. A new 5' UR/Core line probe assay was designed to screen for such variations. Twenty patients tested positively for this special sequence motif, while the other 3 showed the regular subtype 1b sequence. Phylogenetic analysis of the Core sequences further revealed that the latter three were neither related to the main special strain of the infection, nor to each other. These three strains could be traced to two patients already infected at the time of residence in other dialysis units and to one patient who already showed ALT elevations in 1989. Epidemiological studies revealed no traceable source for this outbreak. In conclusion, molecular analysis demonstrates nosocomial transmissions by a peculiar genotype 1b strain in a dialysis center. Three other genotype 1b strains were also present in the unit, but were not responsible for the outbreak.

Comparison of in situ hybridization and immunocytochemistry for the detection of residual beta cells in the pancreas of streptozotocin-treated diabetic rats

The relative efficacy of immunocytochemistry versus in situ hybridization in identifying residual beta cells was studied in rats with streptozotocin-induced diabetes. Consecutive sections of pancreas of streptozotocin-treated diabetic rats and control animals were alternately subjected to in situ hybridization (synthetic oligonucleotides complementary to rat preproinsulin mRNA) and immunocytochemistry (monoclonal antibodies to insulin). The results obtained with both methods were quantitated with the use of computer-assisted image analysis, and the ratio of cells positive by immunocytochemistry to those positive by in situ hybridization was determined. Under normoglycaemic conditions the values obtained by immunocytochemistry correlated well with those obtained by in situ hybridization (immuno/in situ > 95%). In the streptozotocin diabetic animals, however, immunocytochemistry resulted in a distinct underestimation of the number of residual beta cells (immuno/in situ < 80%). This difference was even more striking in small islet cell clusters (< 100 microns) (immuno/in situ 20%). These results suggest that in situ hybridization for prohormone mRNA is the method of choice for the identification of residual or regenerating beta cells with very low insulin content. Caution should be used when interpreting quantitative data in diabetic conditions that are based exclusively on immunocytochemical detection methods.

Prevention of adoptive transfer in BB rats by prophylactic insulin treatment

Prophylactic insulin can prevent diabetes in the BB rat. We evaluated its use to prevent adoptive transfer of diabetes by activated splenocytes. ConA-activated spleen cells from acutely diabetic BB rats were divided into two equal aliquots and injected intravenously in paired diabetes-prone BB rat littermates. At the time of cell injection, subcutaneous insulin injections (15 U.kg-1.day-1) were started in one of each pair (n = 21) of littermates, and the control littermates (n = 21) were injected with saline. The incidence of diabetes, observed 35 days after cell injection, was 95% in control rats compared with 29% in insulin-treated rats (P less than 0.05). To confirm the absence of diabetes, insulin was stopped in all nondiabetic insulin-treated rats at 63 days of age. An OGTT was performed at 65 days of age: 4 rats were glucose intolerant. All rats received comparable numbers of ConA-activated splenocytes. At the time the rats were killed, 3 insulin-treated rats had a completely normal morphology and a normal glucose tolerance. All control rats had insulitis whether they were diabetic or not. No significant difference in any mononuclear subset was observed in relation to insulin treatment. We conclude that prophylactic insulin can prevent adoptive transfer of diabetes in the BB rat without inducing changes in the mononuclear cell subsets.

Comparison of different volume markers in peritoneal dialysis

Four peritoneal volume markers (carbon 14-labeled dextran, dextran blue, radioactive albumin, and hemoglobin) were compared. In six rabbits 14C-dextran was compared with dextran blue during a 4-hour "dwell" with a 4.25% dextrose solution. The recovery of 14C-dextran at the end of the dwell was 71% +/- 3% vs. 92% +/- 1% for dextran blue (P less than 0.001). In six other rabbits, radioactive albumin (RISA) was compared with dextran blue. The recovery of RISA was 78% +/- 4%, compared with 85% +/- 2% for dextran blue (P less than 0.05). The calculated peritoneal volumes, uncorrected for disappearance of the markers, were consistently higher than when correction was made. After correction, the calculated end volumes were similar to actually measured end volumes. In six patients with chronic ambulatory peritoneal dialysis, the intraperitoneal volume during a single dwell of 6 hours was estimated in paired observations with lactated Ringer's solution and 1.5% dextrose dialysate, using simultaneously autologous hemoglobin and RISA. In eight additional patients, a single dwell with 4.25% dextrose dialysate was studied. The recoveries of both markers were related to the osmotic strength of the dialysate. Recoveries were 66.7% +/- 2.3% and 69.6% +/- 0.9% in lactated Ringer's solution, and increased to 81% +/- 3% and 82% +/- 2% in 4.25% dextrose for hemoglobin and RISA, respectively. With each dialysate, after correction for disappearance of the marker, no differences in volume profiles or between calculated or measured end volumes could be found with either hemoglobin or RISA.(ABSTRACT TRUNCATED AT 250 WORDS)

Results of urometabolic evaluation in 127 patients with renal calculous disease

One hundred twenty-seven selected stone formers were evaluated. With the simple ambulatory tests proposed by Pak for metabolic screening and a complete urologic evaluation an anomaly was found in more than 90 per cent of the cases. The patients were divided into three groups: (1) patients operated on for staghorn stones; (2) patients with episodes of spontaneous stone eliminations or young people with only one stone episode; and (3) patients operated on for stone disease. No significant differences were noted except for the occurrence of urinary tract infection and for struvite and calcium oxalate occurrence in the different groups. Urinary tract infection combined with a metabolic disorder appear to make the evolution from small kidney stone to staghorn stone a reality.

Mediastinal angiofollicular lymph node hyperplasia with systemic manifestations

This case report concerns a 19-year-old girl with a mediastinal angiofollicular lymph node hyperplasia (Castleman tumour), with histological aspects of both hyalin vascular and plasma cell type. Systemic manifestations were also noticed. A lymphocytic infiltration of the bone marrow and a change in the lactic dehydrogenase iso-enzyme pattern with an increase of LDH3 were noted. After surgical removal of the mediastinal tumour complete recovery and normalisation of biological abnormalities occurred.

Evaluation of hemofiltration with different AN 69 membrane devices using a discontinuous flow-single needle system

Unipuncture hemofiltration using the double headed pump (Bellco BL 760) was performed in a patient who acted as her own control for 10 sessions with a 1.0 m2 AN69 membrane (group A), 10 sessions with a 1.4 m2 AN69 membrane (group B) and 10 sessions with a 1.0 m2 AN69 membrane Filtral (group C). A two needle standard hemofiltration technique (Hemoprocessor Sartorius) was used in this patient for 10 sessions with a 1.0 m2 AN69 membrane (group D). To obtain the same amount of ultrafiltration fluid the filtration time was respectively 266, 196, 214 and 260 minutes in groups A, B, C and D.

Gardnerella vaginalis (hemophilus vaginalis), an unusual cause of peritonitis in C.A.P.D

Gardnerella vaginalis is usually associated with nonspecific bacterial vaginitis. This paper presents a CAPD patiënt with peritonitis due to G. vaginalis. The infection route remained speculative. Treatment with gentamicin was not successful while the clinical signs of peritonitis disappeared within 24 hours after starting cefazolin.

Pharmacokinetics of digoxin in C.A.P.D

The peritoneal elimination of digoxin during C.A.P.D. was studied in five patients. The plasma half life of digoxin varied from 54 hours to 141 hours. Only 7 to 24 micrograms was eliminated via the peritoneal route during 3 to 4 days C.A.P.D. treatment. The total urinary elimination during the same period ranged from 11 to 57 micrograms. It is concluded that adjustment of dose is not necessary when starting C.A.P.D.

Plasma vitamin A in haemodialysis patients

Different high performance liquid chromatographic systems were applied to the investigation of vitamin A metabolism in subjects undergoing haemodialysis. Plasma levels of retinol, retinyl esters and retinoic acid were measured. There was a significant elevation of plasma retinol and dialysis failed to normalise this level. No correlation with plasma concentrations of creatinine or urea was found. No differences in retinyl ester and retinoic acid levels were observed between healthy subjects and haemodialysis patients. These results suggest that retinol accumulation is not caused by a deficiency in its oxidative metabolism.

Double lumen needle in unipuncture dialysis type double headpump

Single needle dialysis is used as a method of vascular access in many European dialysis centres. However, recirculation has been incriminated as a disadvantage of this procedure. According to in vitro studies, recirculation should be limited to a minimum when using double lumen needles. The present study makes an in vitro comparison between single and double lumen needles in unipuncture (single needle) dialysis of the type double headpump (Bellco, BL 760) and studies the role of recirculation in dialysis performance. Although recirculation is significantly reduced with the double lumen needle, compared to the single lumen needle, the clearance of small molecules is not significantly different for both needle types.

Influences of stress, age and sex on serum growth hormone and free fatty acid levels in cattle

The serum growth hormone (BGH) and free fatty acid (FFA) concentrations of large groups of calves (male and female ranging in age from 8 to 14 days and from 3 to 6 months old), bulls, oxen, heifers and cows under normal conditions were compared with the serum BGH and FFA values of corresponding large groups of animals under stress conditions. Stress was caused by transport, as it routinely occurs, and was further reinforced by a stay of several hours in unfamiliar surroundings. Stress provokes a significant increase in serum FFA in all groups and induced a significant decrease in serum BGH in all groups, with the exception of the non-pregnant heifers. The male and female calves which were 8 to 14 days old, had significantly higher BGH levels than the older animals. The female calves from 3 to 6 months of age, and the heifers had significantly lower BGH levels than the cows. The males had higher serum BGH values than the females, but a significant difference could be demonstrated only between the male and female calves of both age-groups. The oxen, which were 1 to 3 years old, had significantly higher BGH levels than the non-pregnant heifers of the same age. It appeared that gestation had no influence on the serum BGH and FFA levels of both heifers and cows.

Influence of serum free fatty acid levels on growth hormone secretion in lactating cows

The influence of intravenous injections or infusions of insulin (0-2 i.u./kg), propranolol (150 mg), 3,5-dimethylpyrazole (3 mg/kg), 3,5-dimethylisoxazole (0-08 mg/kg), glucose (0-5 g/kg), nicotinic acid (120 mg/kg), arginine (0-5 g/kg) or butyrate (0-5 mmol/kg) on plasma glucose levels, and on serum concentrations of growth hormone and free fatty acids of lactating cows was investigated. In all of these experiments we noted an increase in the level of growth hormone. This increase was not a direct consequence of alterations in the glucose concentration, since the growth hormone peak occurred both during a decrease (insulin, 3,5-dimethylisoxazole, nicotinic acid and butyrate tests), and during an increase of the glucose level (glucose, arginine and propranolol tests), whereas the glucose concentration remained unchanged during the 3,5-dimethylpyrazole experiments. However, in each instance a precipitous fall of the free fatty acid level was noted. The glucose, growth hormone, and free fatty acid levels of lactating cows were not affected by either i.v. injection or infusion of saline.