Prophylaxis with oral penicillin in children with sickle cell anemia. A randomized trial

Children with sickle cell anemia have an increased susceptibility to bacterial infections, especially to those caused by Streptococcus pneumoniae. We therefore conducted a multicenter, randomized, double-blind, placebo-controlled clinical trial to test whether the regular, daily administration of oral penicillin would reduce the incidence of documented septicemia due to S.pneumoniae in children with sickle cell anemia who were under the age of three years at the time of entry. The children were randomly assigned to receive either 125 mg of penicillin V potassium (105 children) or placebo (110 children) twice daily. The trial was terminated 8 months early, after an average of 15 months of follow-up, when an 84 percent reduction in the incidence of infection was observed in the group treated with penicillin, as compared with the group given placebo (13 of 110 patients vs. 2 of 105; P = 0.0025), with no deaths from pneumococcal septicemia occurring in the penicillin group but three deaths from the infection occurring in the placebo group. On the basis of these results, we conclude that children should be screened in the neonatal period for sickle cell hemoglobinopathy and that those with sickle cell anemia should receive prophylactic therapy with oral penicillin by four months of age to decrease the morbidity and mortality associated with pneumococcal septicemia.

A study of hormone replacement therapy in postmenopausal women with ischaemic heart disease: the Papworth HRT Atherosclerosis Study

OBJECTIVE

To assess the possible benefit of hormone replacement therapy (HRT) in the secondary prevention of ischaemic heart disease.

DESIGN

A prospective randomised trial of transdermal HRT in women with definite ischaemic heart disease.

SETTING

A regional cardiac unit.

POPULATION

Postmenopausal women with angiographically proven ischaemic heart disease.

METHODS

A total of 255 postmenopausal women with angiographically proven ischaemic heart disease were recruited and randomised; 134 were treated with transdermal HRT and 121 acted as controls. The women were seen at six monthly intervals. The primary end points, which were determined by a blinded assessor, were admission to hospital with unstable angina, proven myocardial infarction or cardiac death. A total of 53 (40%) patients withdrew from the HRT group and eight (7%) from the control group. The mean duration of follow up was 30.8 months.

MAIN OUTCOME MEASURES

Admission to hospital with unstable angina, proven myocardial infarction or cardiac death.

RESULTS

During follow up, there were 53 primary end-point events in the HRT group and 37 in the control group. Using an intention-to-treat analysis, the primary end-point event rate was 15.4 events per 100 patient years for the HRT group compared with 11.9 for the control group (event rate ratio 1.29 (95% CI 0.84-1.95, P = 0.24)). Using a per-protocol analysis, there was an event rate ratio of 1.49 (0.93-2.36, P = 0.11) for the HRT arm compared with the control arm. Particularly during the first two years of follow up, the HRT group had a higher, but not statistically significant, event rate than the control group.

CONCLUSION

Our findings suggest that transdermal HRT should not be commenced for the purpose of secondary prevention in postmenopausal women with angiographically proven ischaemic heart disease.

A U-Net Deep Learning Framework for High Performance Vessel Segmentation in Patients With Cerebrovascular Disease

Brain vessel status is a promising biomarker for better prevention and treatment in cerebrovascular disease. However, classic rule-based vessel segmentation algorithms need to be hand-crafted and are insufficiently validated. A specialized deep learning method-the U-net-is a promising alternative. Using labeled data from 66 patients with cerebrovascular disease, the U-net framework was optimized and evaluated with three metrics: Dice coefficient, 95% Hausdorff distance (95HD) and average Hausdorff distance (AVD). The model performance was compared with the traditional segmentation method of graph-cuts. Training and reconstruction was performed using 2D patches. A full and a reduced architecture with less parameters were trained. We performed both quantitative and qualitative analyses. The U-net models yielded high performance for both the full and the reduced architecture: A Dice value of ~0.88, a 95HD of ~47 voxels and an AVD of ~0.4 voxels. The visual analysis revealed excellent performance in large vessels and sufficient performance in small vessels. Pathologies like cortical laminar necrosis and a rete mirabile led to limited segmentation performance in few patients. The U-net outperfomed the traditional graph-cuts method (Dice ~0.76, 95HD ~59, AVD ~1.97). Our work highly encourages the development of clinically applicable segmentation tools based on deep learning. Future works should focus on improved segmentation of small vessels and methodologies to deal with specific pathologies.

Intestinal absorption of the intact peptide carnosine in man, and comparison with intestinal permeability to lactulose

1. Healthy humans ingested the dipeptide carnosine (L-beta-alanyl-L-histidine). Their plasma levels and urinary outputs of carnosine and beta-alanine were monitored over the following 5 h. 2. Large amounts of intact carnosine (up to 14% of the ingested dose) were recovered in the urine over the 5 h after ingestion. However, carnosine was undetectable in the plasma unless precautions were taken to inhibit blood carnosinase activity ex vivo during and after blood collection. 3. The amount of carnosine recovered in urine varied substantially between subjects. It correlated negatively with carnosinase enzymic activity in the plasma. Highest carnosinase activities were observed in those subjects who regularly underwent physical training. 4. Urinary recovery of the disaccharide lactulose also varied considerably between subjects, but was substantially lower than that of carnosine. There was no significant correlation between the recoveries of carnosine and lactulose. 5. When lactulose was ingested with a hypertonic solution, the urinary recovery of lactulose was generally increased. When carnosine was ingested with a hypertonic solution, the urinary recovery of carnosine was reduced: hence the paracellular route probably is not dominant for absorption of intact carnosine. 6. Intact carnosine must have crossed the intestine to an extent much greater than hitherto recognized. Rapid post-absorptive hydrolysis is a severe obstacle to quantification of intact peptide absorption.

The effect of dietary supplementation with vitamins A, C and E on cell-mediated immune function in elderly long-stay patients: a randomized controlled trial

Thirty elderly long-stay patients were randomly allocated to receive either placebo or dietary supplementation with vitamins A, C and E for 28 days. Nutritional status and cell-mediated immune function were assessed before and after the period of supplementation. Following vitamin supplementation, cell-mediated immune function improved as indicated by a significant increase in the absolute number of T cells (p less than 0.05), T4 subsets (p less than 0.05), T4 to T8 ratio (p less than 0.01) and the proliferation of lymphocytes in response to phytohaemagglutinin (p less than 0.01). In contrast, no significant changes were noted in the immune function of the placebo group. We conclude that supplementation with the dietary antioxidants vitamins A, C and E can improve aspects of cell-mediated immune function in elderly long-stay patients.

Vitamin status in treated patients with cystic fibrosis

The water-soluble (B1, B2, B6, C, folic acid) and fat-soluble vitamin (A, carotene, E, and D) status of 36 patients with cystic fibrosis was assessed and compared with a control group of 21 age-matched normal children. Twenty-seven of the patients were receiving vitamin supplements (except folic acid and vitamin E) at the time of investigation. Vitamin B1, B2, and B6 status was adequate in all patients, and there was little evidence of folic acid deficiency. Vitamin C stores might not have been adequate in some of these patients, despite daily supplements with 50 mg of the vitamin. Steatorrhoea, often severe, was present in most of them. Serum carotene and vitamin E concentrations were low in over 90% of patients and were related to the severity of steatorrhoea. Vitamin A was low in over 40% of the patients despite daily vitamin supplements of 4000 IU and correlated with the serum retinol-binding protein level. Serum 25-OH cholecalciferol was low in some patients whether or not they were receiving a daily supplement of 400 IU vitamin D. In a short-term supplementation trial with water-miscible preparations of vitamin A and E in 14 patients, the serum levels of both vitamins responded well to 2 weeks of treatment with 50 mg vitamin E and 4000 IU vitamin A. Except for serum vitamin A, which was lowest in patients with the poorest clinical grading, the other vitamins were not influenced by the clinical grade of the patients.

Plasma and urinary zinc in patients with malabsorption syndromes or hepatic cirrhosis

Plasma and urinary zinc have been measured in 19 patients with malabsorption and 21 patients with hepatic cirrhosis. The results have been compared with those of 20 control subjects and 23 patients with a variety of other diseases. The diurnal variation in plasma zinc levels has been confirmed and is of such magnitude that this must be taken into account in comparing results in groups of subjects. Plasma zinc levels, both fasting and after a meal, are significantly lower in patients with cirrhosis (71 and 60 mug/100 ml) and malabsorption (76 and 64 mug/100 ml) than in controls (97 and 81 mug/100 ml). In the patients with cirrhosis or malabsorption similar correlations exist between plasma zinc and plasma albumin, suggesting that the low plasma zinc levels may be, at least in part, dependent on the plasma albumin level. Urinary zinc excretion is increased in cirrhosis, but not in malabsorption, indicating that increased urinary loss is unlikely to explain the low plasma levels.

T-lymphocyte subsets and interleukin-2 production in zinc-deficient rats

1. It has been suggested that zinc-deficiency impairs cellular (T-lymphocyte-mediated) immune responses via a selective effect on helper T-lymphocytes. We have addressed this question in the rat by employing recently developed reagents in the form of monoclonal antibodies which specifically identify rat T-lymphocyte subsets (identifying total T-cells, helper T-cells and suppressor T-cells) and also by quantifying helper T-cell function by measurement of the helper T-cell-derived molecule interleukin-2 (IL-2). 2. Zn-deficiency induced T-cell atrophy (assessed morphologically and phenotypically with anti-rat T-cell monoclonal antibodies) in both peripheral blood and spleen. The use of these specific monoclonal antibodies failed to demonstrate a selective effect of Zn deficiency on the helper T-cell fraction of the total T-lymphocyte population. 3. In contrast, the results of functional assays of the T-lymphocyte response were dependent on the conditions of culture but suggested that the generation of IL-2 and its corresponding receptor were determined by the intracellular Zn status. Thus, in vivo, helper T-lymphocyte numbers are non-specifically reduced since other T-cell subsets are also reduced in response to appropriate stimulation. The functional consequences of this are dependent on the intracellular concentration of Zn but appear to influence both IL-2 production and its receptors on activated T-cells.

Ascorbic acid: a factor concentrated in human gastric juice

1. Concentrations of ascorbic acid (ascorbic and dehydro-ascorbic; A + D; measured by the 2,4-dinitrophenylhydrazine method) of nearly three times those of plasma are present in gastric juice samples from patients with normal gastric histology. 2. A significant reduction in gastric juice ascorbic acid (A + D) was observed in patients with chronic gastritis. This reduction in concentration was independent of the grade of gastritis. 3. Concentrations of ascorbic acid (A + D) in gastric biopsy specimens were consistently higher in the antrum than in the body of the stomach. 4. These data demonstrate that considerable quantities of ascorbic acid (A + D) are normally 'secreted' into the stomach. 5. Ascorbic acid (ascorbic only; A; measured by h.p.l.c.) was present predominantly in its biologically active form in the patients with normal gastric histology. However, in patients with gastritis, independent of grade, ascorbic acid was present predominantly in its oxidized, biologically inactive form.

The effect of pectin on the structure and function of the rat small intestine

1. The effect of pectin on the structure and function of the rat small intestine was compared with that of a standard pellet diet and of a fibre-free basal diet. 2. The length and wet weight of the small bowel was significantly greater inpect in-fed rats than in either pellet- or basal-diet-fed rats. 3. Histological measurements of longitudinal sections from the small bowel showed a significantly greater crypt depth and muscle layer thickness in the mid-jejunum and ileum of the pectin fed rats. Villous height showed less variation. 4. The specific activity of alkaline phosphatase (EC 3.1.3.1) and leucyl-beta-naphthylamidase (EC 3.4.11.1) in mucosal scrapings was significantly lower in the upper jejunum of pectin-fed rats compared with either of the other dietary groups. The differences were not so marked in mid-jejunum or ileum. 5. Glucose absorption measured in vivo from jejunal and ileal loops was similar in all three dietary groups. 6. With two minor exceptions there were no significant differences in any of these measurements between the pellet- and basal-diet-fed rats. 7. These findings could be explained by increased epithelial cell turnover caused by pectin. The possible mechanisms of this are discussed. 8. The effect of pectin on the human small bowel requires study before it can be widely prescribed in man.

Comparison of four pancreatic extracts in cystic fibrosis

Four different pancreatin products, Pancrease, Creon, Pancrex V Forte, and Pancreatin Merck, were compared in a random crossover trial in children with cystic fibrosis. The results of our study showed that patients who received Creon and Pancrease had fewer gastrointestinal symptoms than patients who received Pancrex V Forte and Pancreatin Merck. Fat absorption was significantly improved with Pancrease when compared with Pancrex V forte and Pancreatin Merck. Also the fat absorption with Creon was superior to that with Pancrex V Forte. There was no significant difference in fat absorption between Pancrease and Creon. Pancrex V Forte and Pancreatin Merck, or Pancreatin Merck and Creon. Faecal nitrogen content was less with both Creon and Pancrease compared with Pancreatin Merck. Creon and Pancrease allow the patient with cystic fibrosis to take a high energy diet without any dietary restrictions.

Alcohol consumption in patients with colorectal adenomatous polyps

The risk of developing colorectal adenomatous polyps is probably increased by a variety of dietary and environmental factors. We found an association with current alcohol and cigarette consumption. The risk of polyps was increased three times in drinkers who did not smoke and two times in smokers who did not drink, with those who both drank and smoked having 12 times the risk of total abstainers. Since colonic adenomatous polyps are generally regarded as premalignant lesions, these results lend support to the view that alcohol consumption may be an important factor in the pathogenesis of colorectal neoplasia, thus reinforcing the proposed polyp/carcinoma sequence in colorectal carcinogenesis. The role of smoking, however, is less clear particularly since the lack of association of colorectal carcinoma and smoking has been reported in many other studies.

The absorption of alpha-tocopherol in man

1. Physiological oral doses of DL [5-Me-3H]α-tocopherol were administered to fasting subjects with various disease states, with and without steatorrhoea, and net absorption was calculated by measurement of faecal unabsorbed radioactivity. In each subject studied more than 70% of the faecal radioactivity was excreted as unchanged α-tocopherol.

2. α-Tocopherol absorption was significantly less in subjects with steatorrhoea (mean 59.4%, range 31–83%) than in those without steatorrhoea (mean 72.4%, range 51–86%). Nineteen out of twenty-four subjects with steatorrhoea absorbed less than 65% of the α-tocopherol dose, while twenty-two out of twenty-six subjects without steatorrhoea absorbed more than 65%. There was a significant correlation between the severity of steatorrhoea and α-tocopherol absorption. In a wide range of diseases steatorrhoea appeared to be the common factor associated with a decrease in α-tocopherol absorption; however, in subjects after gastric surgery α-tocopherol absorption was often low even in the absence of steatorrhoea, and this may be an important factor in explaining the high incidence of vitamin E deficiency in such patients.

3. Radioactivity in the plasma was maximal 6–12 h after dosing. Plasma radioactivity curves were significantly lower in patients with steatorrhoea than in those without steatorrhoea, but there was considerable overlap. In some patients with severe deficiency and severe steatorrhoea there was no detectable plasma response even with considerable absorption of up to 40% of the administered dose. Three patients with severe dietary deficiency of the vitamin and no steatorrhoea also showed a decreased plasma radioactivity.

4. Three subjects were studied twice, initially when deficient in α-tocopherol and a second time after repletion with α-tocopherol acetate. There was no evidence for a compensatory mechanism to increase α-tocopherol absorption in α-tocopherol deficiency.

5. A small quantity of the administered dose (almost always less than 6%) was excreted in the urine.

Nutrition in cryptogenic cirrhosis and chronic aggressive hepatitis

The nutritional status of 80 patients with non-alcoholic chronic liver disease was assessed by determination of various nutritional parameters in body fluids. With the exception of vitamin C there was a higher incidence (40%) of fat soluble vitamin deficiency (vitamins A, E, and carotene) than of the water soluble vitamins. Less than 10% of patients showed evidence of vitamin B12, nicotinic acid, thiamin, or riboflavin deficiency, and 17% had evidence of folic acid deficiency. The presence of deficiency was not related to age of the patient or fat absorption, and an inadequate dietary intake was not a major cause of deficiency. The incidence of nutritional deficiency is less frequent in non-alcoholic as compared with alcoholic liver disease.

Improved diagnostic accuracy of a modified oral pancreatic function test

The oral pancreatic function test (PFT) depends upon urinary recovery of p-aminobenzoic acid (PABA) released by chymotrypsin hydrolysis of orally administered N-benzoyl-L-tyrosyl-p-aminobenzoid acid. The diagnostic value of the test is limited because falsely abnormal results frequently occur in patients with bowel or liver disease in whom PABA recovery is impaired by abnormal absorption or hepatic conjugation, even though pancreatic function is normal. To overcome this problem, we have modified the oral PFT to correct for impaired PABA absorption and conjugation. Results of the oral PFT have been compared with urinary recovery of an equivalent dose of free PABA in order to derive a PABA excretion index (PEI). When the modified oral PFT is used, the PEI clearly distinguished patients with pancreatic disease from normal subjects. In patients with small-bowel or liver disease and normal exocrine pancreatic function, the PEI results were similar to those of normal subjects, although a previous oral PFT had been falsey abnormal. The modified test can therefore distinguish abnormal results due to pancreatic disease from the falsely abnormal results found in liver and small-bowel disease.

Hickman catheter complications in marrow transplant recipients

The complications associated with the insertion and use of 95 single lumen and 312 double lumen Hickman right atrial catheters in 357 marrow transplant recipients were retrospectively analyzed. Three-hundred (84%) first inserted catheters were in place for a median of 93 days (range, 16-209) without complications and were removed electively. Thirty-nine (9.6%) of all catheters were removed for infections and 24 (5.9%) for mechanical complications. Ninety-five patients (26.6%) had 111 episodes of septicemia involving 128 separate organisms and 25 patients had 25 episodes of localized catheter infection with 26 separate organisms. The most frequently isolated organism was coagulase-negative staphylococcus. Twelve of 24 removals due to mechanical complications were caused by accidental pulling of the catheter by the patient.

Functional recovery of the exocrine pancreas after acute pancreatitis

A tubeless pancreatic function test (BTP test) using N-benzoyl-l-tyrosyl-p-aminobenzoic acid was used to assess exocrine function from urinary recovery of p-aminobenzoic acid produced by hydrolysis of the peptide by chymotrypsin. Patients with acute pancreatitis were studied at various time intervals after the acute attack and compared with controls with abdominal pain that was not pancreatic in origin. The initial BTP test carried out in the convalescent period was abnormal in all of 30 patients with acute pancreatitis but normal in 10 patients with non-pancreatic abdominal pain and also in 8 patients who had recovered from an attack of acute pancreatitis 2-6 years previously. Results were improved or normal in 12 of 15 patients re-tested 1 year after the attack of pancreatitis, but 4 out of 6 still had abnormal results 2-6 months after the attack. The data suggest that an attack of acute pancreatitis may impair exocrine pancreatic function for several months.

Genetic hitchhiking in spatially extended populations

When a mutation with selective advantage s spreads through a panmictic population, it may cause two lineages at a linked locus to coalesce; the probability of coalescence is exp(-2rT), where T∼log(2Ns)/s is the time to fixation, N is the number of haploid individuals, and r is the recombination rate. Population structure delays fixation, and so weakens the effect of a selective sweep. However, favourable alleles spread through a spatially continuous population behind a narrow wavefront; ancestral lineages are confined at the tip of this front, and so coalesce rapidly. In extremely dense populations, coalescence is dominated by rare fluctuations ahead of the front. However, we show that for moderate densities, a simple quasi-deterministic approximation applies: the rate of coalescence within the front is λ∼2g(η)/(ρℓ), where ρ is the population density and ℓ=σ2/s is the characteristic scale of the wavefront; g(η) depends only on the strength of random drift, η=ρσs/2. The net effect of a sweep on coalescence also depends crucially on whether two lineages are ever both within the wavefront at the same time: even in the extreme case when coalescence within the front is instantaneous, the net rate of coalescence may be lower than in a single panmictic population. Sweeps can also have a substantial impact on the rate of gene flow. A single lineage will jump to a new location when it is hit by a sweep, with mean square displacement σeff(2)/σ(2)=(8/3)(L/ℓ)(Λ/R); this can be substantial if the species' range, L, is large, even if the species-wide rate of sweeps per map length, Λ/R, is small. This effect is half as strong in two dimensions. In contrast, the rate of coalescence between lineages, at random locations in space and on the genetic map, is proportional to (c/L)(Λ/R), where c is the wavespeed: thus, on average, one-dimensional structure is likely to reduce coalescence due to sweeps, relative to panmixis. In two dimensions, genes must move along the front before they can coalesce; this process is rapid, being dominated by rare fluctuations. This leads to a dramatically higher rate of coalescence within the wavefront than if lineages simply diffused along the front. Nevertheless, the net rate of coalescence due to a sweep through a two-dimensional population is likely to be lower than it would be with panmixis.

Relation between zinc status and hepatic functional reserve in patients with liver disease

Patients with liver disease may be at risk of zinc depletion. We measured polymorphonuclear cell, mononuclear cell, plasma, and erythrocyte zinc values, and erythrocyte carbonic anhydrase activity to assess zinc status in 17 patients with non-alcoholic liver disease (primary biliary cirrhosis and chronic active hepatitis) and 13 patients with alcoholic liver disease. The plasma zinc concentration was reduced in both patient groups and correlated strongly with the plasma albumin concentration. The mean polymorphonuclear cell zinc value in both groups was similar to that of controls but when results were combined and grouped according to hepatic functional reserve, patients with more severe liver damage (grade C) had a lower polymorphonuclear cell zinc value (mean (SD) 0.86 (0.24) nmol/mg protein) than patients with grade A (1.44 (0.43) nmol/mg protein, p less than 0.01) or grade B liver damage (1.08 (0.30) nmol/mg protein, p less than 0.05), or control subjects (1.26 (0.28) nmol/mg protein, p less than 0.001). The polymorphonuclear cell zinc value did not correlate with other indices of zinc status. The mononuclear cell zinc value was normal in all patients and was unrelated to hepatic damage. The erythrocyte zinc value and carbonic anhydrase activity were raised in alcoholic patients only. Since the polymorphonuclear cell zinc concentration is low in human experimental zinc deficiency and also correlates with tissue zinc, we suggest that our results provide evidence of progressive leucocyte zinc depletion in patients with liver disease.