Control of experimental pulmonary tuberculosis depends more on immunostimulatory leukotrienes than on the absence of immunosuppressive prostaglandins.

Prostaglandins (PGs) and leukotrienes (LTs) are produced in Mycobacterium tuberculosis (Mtb)-infected lungs and have immune suppressive and protective effects, respectively. Considering that both of these mediators are produced during mycobacterial infection, we investigated the specific and relative biological importance of each in regulating host response in experimental tuberculosis. Administration of celecoxib, which was found to reduce lung levels of PGE(2) and increase LTB(4), enhanced the 60-day survival of Mtb-infected mice in 14%. However administration of MK-886, which reduced levels of LTB(4) but did not enhance PGE(2), reduced 60-day survival from 86% to 43% in Mtb-infected mice, and increased lung bacterial burden. MK-886 plus celecoxib reduced survival to a lesser extent than MK-886 alone. MK-886- and MK-886 plus celecoxib-treated animals exhibited reduced levels of the protective interleukin-12 and gamma-interferon. Our findings indicate that in this model, the protective effect of LTs dominates over the suppressive effect of PGs.

Differential kinase requirement for enhancement of Fc gammaR-mediated phagocytosis in alveolar macrophages by leukotriene B4 vs. D4.

In alveolar macrophages, leukotriene (LT) B(4) and cysteinyl LTs (LTC(4), LTD(4) and LTE(4)) both enhance Fc gamma receptor (Fc gammaR)-mediated phagocytosis. In the present study we investigated the role of specific PKC isoforms (PKC-alpha and -delta), the MAP kinases p38 and ERK 1/2, and PI3K in mediating the potentiation of Fc gammaR-mediated phagocytosis induced by addition of leukotrienes to the AMs. It was found that exogenously added LTB(4) and LTD(4) both enhanced PKC-delta and -alpha phosphorylation during Fc gammaR engagement. Studies with isoform-selective inhibitors indicated that exogenous LTB(4) effects were dependent on both PKC-alpha and -delta, while LTD(4) effects were exclusively due to PKC-delta activation. Although both exogenous LTB(4) and LTD(4) enhanced p38 and ERK 1/2 activation, LTB(4) required only ERK 1/2, while LTD(4) required only p38 activation. Activation by both LTs was dependent on PI3K activation. Effects of endogenous LTs on kinase activation were also investigated using selective LT receptor antagonists. Endogenous LTB(4) contributed to Fc gammaR-mediated activation of PKC-alpha, ERK 1/2 and PI3K, while endogenous cysLTs contributes to activation of PKC-delta, p38 and PI3K. Taken together, our data show that the capacities of LTB(4) and LTD(4) to enhance Fc gammaR-mediated phagocytosis reflect their differential activation of specific kinase programs.

TLR4/MYD88-dependent, LPS-induced synthesis of PGE2 by macrophages or dendritic cells prevents anti-CD3-mediated CD95L upregulation in T cells.

Antigen-presenting cells (APCs) control T-cell responses by multiple mechanisms, including the expression of co-stimulatory molecules and the production of cytokines and other mediators that control T-cell proliferation, survival and differentiation. Here, we demonstrate that soluble factor(s) produced by Toll-like receptor (TLR)-activated APCs suppress activation-induced cell death (AICD). This effect was observed in non-stimulated APCs, but it was significantly increased after lipopolysaccharide (LPS) treatment. Using different KO mice, we found that the LPS-induced protective factor is dependent on TLR4/MyD88. We identified the protective factor as prostaglandin E(2) (PGE(2)) and showed that both APC-derived supernatants and PGE(2) prevented CD95L upregulation in T cells in response to TCR/CD3 stimulation, thereby avoiding both AICD and activated T cell killing of target macrophages. The PGE(2) receptors, EP2 and EP4, appear to be involved since pharmacological stimulation of these receptors mimics the protective effect on T cells and their respective antagonists interfere with the protection induced by either APCs derived or synthetic PGE(2). Finally, the engagement of EP2 and EP4 synergistically activates protein kinase A (PKA) and exchange protein directly activated by cAMP pathways to prevent AICD. Taken together, these results indicate that APCs can regulate T-cell levels of CD95L by releasing PGE(2) in response to LPS through a TLR4/MyD88-dependent pathway, with consequences for both T cell and their own survival.

Electrophysiological assessment of brain function in severe malnutrition.

Brain function in 10 severely malnourished children and matched controls was assessed using spectral analysis of electroencephalographic responses to photic driving during slow-wave sleep. The percentage power in the classical EEG broad-band domains was derived from temporo-occipital records. The malnourished group (5-23 months old; z-score height-for-age -3.2 +/- 0.3, weight-for-height -2.5 +/- 0.3) were tested on admission and on discharge from hospital. No significant differences were found between admission and discharge. Significant differences were found between malnourished and control groups, in the alpha 1 band in the undriven EEG, and in the alpha/beta 1 power ratio while driving at 8 Hz. These electrophysiological abnormalities, persisting despite somatic rehabilitation, must be associated with the chronic rather than the acute aspects of malnutrition, and can index the deviation of brain function from normality.

Glyoxalase I activity in erythrocytes from severely malnourished children.

The enzyme glyoxalase I (Glyox I) is involved in metabolic detoxification, and requires glutathione (GSH) as a cofactor. Given the low concentration of whole blood GSH in children with oedematous malnutrition, it is possible that the function of this pathway may be compromised in these children. Glyox I activity was therefore assayed in erythrocytes taken from 133 severely malnourished children and 21 age-matched controls. The mean values (+/- SEM) for the marasmic group (Marasmus: 105 +/- 4/u/gm Hb) and the group with kwashiorkor (Kwash: 103 +/- 4/u/gm Hb) were not significantly different from controls (Cont: 104 +/- 2 u/gm Hb). In the group with marasmic-kwashiorkor (M-K: 88 +/- 4 u/g Hb) Glyox I activity was significantly lower than in controls (p < 0.005), as well as in children with Marasmus (p < 0.005), and kwashiorkor (p < 0.05). Enzyme activity was lower than normal in 45% of the MK group. Seven children died subsequent to admission; in five cases Glyox I activities were exceedingly low. There was a weak positive correlation between Glyox I activity and whole blood levels of GSH (r = 0.215). We conclude that Glyox I activity is relatively unaffected in malnutrition, except in those with M-K and especially those who do not survive the acutely malnourished state.

Maternal immunity to measles and infant immunity at less than twelve months of age relative to maternal place of birth.

Sera from infants aged 5 to 11 months and from their mothers were used to investigate the level and duration of transplacentally derived measles antibody. The infants of foreign-born, inner-city mothers were more likely to have measles antibody and were less likely to get measles. Infants of foreign-born mothers, because they are less likely to respond to measles vaccine, may require different vaccine strategies than infants of mothers born in the United States.

Pathology of the lungs in childhood malnutrition in Jamaica. Light and electron microscopy.

The autopsy records of 115 children with severe protein-energy malnutrition were reviewed. Sections of the lung histology showed evidence of bacterial pneumonia in 49% of cases. An additional 18% showed bronchitis, bronchiolitis or interstitial pneumonitis. Aspiration of gastric contents was evident in 10% of cases; 6% showed pulmonary oedema and congestion. In the remaining cases, no lung pathology was identified (17%). In 8 cases, rapid autopsy examination permitted fixation of lung tissue for electron microscopy. These included 4 cases of bronchopneumonia, one of which was associated with viral pneumonia. Another interstitial pneumonitis, probably of viral aetiology, was also studied. Both these virus-associated cases showed loss of type I pneumocytes and hyperplasia of type II pneumocytes. Another patient with herpes simplex hepatitis showed necrotic emboli in pulmonary capillaries with virions, as well as colonies of interstitial bacteria. One patient with acute pulmonary oedema displayed severe endothelial cell swelling on electron microscopy. In one case, there was no evidence of respiratory changes, apart from desquamation of type I pneumocytes. Useful information can be obtained on the fine structure of the lung, using samples taken soon after death.

Peroxisomes and the hepatic pathology of childhood malnutrition.

Liver specimens obtained immediately after death from eight severely malnourished children were examined by electron microscopy, and compared with seven liver biopsy specimens from children who had recovered from malnutrition. The liver cells from the fatal cases showed mitochondrial swelling, with coarse densities in the matrix, cholestasis, depletion of the endoplasmic reticulum and Golgi apparatus, diminished glycogen stores, prominent lipid deposits and focal cytoplasmic degradation. The nucleoli were enlarged. There was marked reduction in peroxisomes. In contrast, the biopsies from recovering children showed good cellular organisation, and a normal frequency of peroxisomes. Multiple factors, including sepsis, may lead to depletion of peroxisomes. Loss of peroxisomes may interrupt beta-oxidation of long-chain fatty acids and accentuate the accumulation of lipid. Moreover, a reduction in the concentration of catalase may remove one avenue for the detoxification of free radicals. As the concentration of other anti-oxidants, notably glutathione, is also reduced, free radical damage may occur, leading to lipid peroxidation of membranes, mitochondrial damage, pump failure and influx of water and electrolytes into the cell.

Production of interleukin-6 and tumour necrosis factor-alpha in vitro is reduced in whole blood of severely malnourished children.

1. Cytokine production in vitro was assessed in 16 malnourished children, before and after nutritional recovery. 2. Tumour necrosis factor-alpha and interleukin-6 were measured in whole blood after lipopolysaccharide stimulation. 3. The total amount of both cytokines was significantly less after 24 h incubation among malnourished children when compared with the same children after nutritional rehabilitation. 4. Cytokine production in vitro is impaired in severely malnourished children.

Ultrastructure of the islets of Langerhans in protein-energy malnutrition.

Significant hormonal changes have been reported in childhood malnutrition, including high serum levels of growth hormone and cortisol, and low levels of circulating insulin. The ultrastructure of the endocrine pancreas in such patients has hitherto not been reported. A light microscopy survey of the pancreatic islets was carried out on 69 malnourished children dying from protein-energy malnutrition. In seven of these cases, a rapid autopsy protocol allowed tissues to be fixed for electron microscopy within 75 minutes of death. This paper presents the first ultrastructural observations on the Islets of Langerhans in childhood protein-energy malnutrition. In all cases, there was a variable degree of degeneration of all cell types with membrane damage, loss of ribosomes, vesiculation and mitochondrial swelling. In addition, the B-cells showed a high proportion of precursor granules compared to crystal forms, possibly accounting for low insulin serum levels reported by other workers. It is suggested that islet cell changes may be related to free radical damage secondary to depletion of glutathione and other antioxidants, as well as relative deficiencies of cysteine and zinc. In addition, the effects of agonal anoxia, and a short fixation delay after death must be considered.

Elevated glutathione S-transferase activity in erythrocytes from malnourished children.

Glutathione S-transferases (GSTs) are principally involved in detoxification. These enzymes can be induced by an increased flux of substrate, such as occurs during pro-oxidative stress or antioxidant deficiency. We tested the hypothesis that the postulated oxidative stress in severe malnutrition would result in induction of GSTs in erythrocytes. Erythrocyte GST activity towards 1-chloro-2,4-dinitrobenzene (CDNB) was measured in 271 malnourished children (22 undernourished; 92 marasmic; 82 kwashiorkor; 75 marasmic-kwashiorkor) and 48 healthy children. GST activity in the malnourished children was significantly higher than the control group (P < 0.01). The GST activity in the four classes of malnutrition did not differ. There was a weak relationship between GST activity and the height deficit, but not with the weight deficit, or the clinical features displayed by the children. The 11 children that died had a higher value than the survivors. There was no change in GST with anthropometric recovery. We conclude that erythrocyte GST has been induced in children with malnutrition. Induction of erythrocyte GST may be the result of exposure of the children to oxidative stress during the months prior to their presentation with severe malnutrition.

Acute-phase protein response is impaired in severely malnourished children.

1. The responses of plasma levels of C-reactive protein and serum amyloid A were assessed in two groups of malnourished children. 2. Sixty-six severely malnourished children were studied at admission. Fifty of these had clinical and/or laboratory evidence of infection. C-reactive protein was not elevated in 23 (46%) and serum amyloid A was not raised in 29 (58%) of these 50 children. 3. Surviving children (n = 62) received two doses of diphtheria-pertussis-tetanus vaccine, to which the C-reactive protein and serum amyloid A responses were measured. The first was given early in recovery, the second after nutritional rehabilitation. Ten mildly malnourished children acted as controls, receiving a single dose of diphtheria-pertussis-tetanus vaccine. 4. The responses of both C-reactive protein and serum amyloid A to diphtheria-pertussis-tetanus vaccine were significantly less in early recovery than after nutritional recovery. The response of the mildly malnourished group was no different from that of the severely malnourished group in early recovery, but was less than their response on discharge. 5. The acute-phase protein response of malnourished children is impaired. This may have prognostic implications as the response plays a central role in promoting healing.

Coagulase-negative staphylococcal bacteremia in severely malnourished Jamaican children.

Immunosuppression increases the susceptibility to infection and changes the inflammatory response in children with severe protein-energy malnutrition. In this 5-year prospective study bacteremia was documented in 16% of 336 severely malnourished children, 2 to 34 months of age, who were hospitalized consecutively in the Tropical Metabolism Research Unit, Kingston, Jamaica. The 53 children had 60 episodes of nosocomial and community-acquired bacteremia with 69 blood isolates. Community-acquired bacteremia accounted for 72% (43 of 60) of bacteremic episodes. Thirty-five percent (24 of 69) of the strains were coagulase-negative staphylococci, 19% (13 of 69) were Staphylococcus aureus and 11% (8 of 69) were Streptococcus Group D. Seventeen episodes of coagulase-negative staphylococcal bacteremia were acquired in the community and 7 were nosocomial. These patients were more likely to have pneumonic consolidation than children with all other bacteremias combined (P < 0.02, Fisher's exact test). The bacteremia-related case fatality rate was 8% (5 of 60). Polymicrobial and Gram-negative septicemia were independent positive predictive factors for mortality when compared with single-agent and Gram-positive sepsis (P < 0.02). This 71% (49 of 69) prevalence of Gram-positive organisms suggests a change in the epidemiology from the predominant Gram-negative etiologies (76%) described in previous reports.

Ultrasonographic assessment of the extent of hepatic steatosis in severe malnutrition.

Ultrasonographic, blinded assessment was made of the extent of hepatic steatosis in 55 children with severe malnutrition: undernutrition (n = 6), marasmus (n = 18), marasmickwashiorkor (n = 17), and kwashiorkor (n = 14). The children were examined on admission, in early recovery (considered as baseline), and again at discharge. Eleven healthy control children and eight of the previously malnourished children were studied as comparison groups. Both oedematous and non-oedematous malnourished children had significantly more steatosis than the comparison groups at each time. Children with oedematous malnutrition had significantly greater steatosis than non-oedematous children at admission. Half of the non-oedematous malnourished children had appreciable hepatic steatosis at both admission and at baseline. Hepatic fat was only slowly mobilised. The rate constant was 1.4 +/- 0.3%/day. One quarter of the children did not change steatosis grades during the period they were in hospital. There was no overall correlation between the extent of steatosis and liver size. Hepatic steatosis in childhood malnutrition is not confined to oedematous children: it is frequently present in marasmic and undernourished children. Its extent is not necessarily related to the degree of hepatomegaly and accumulated lipid is only slowly mobilised.

Effect of zinc on lean tissue synthesis during recovery from malnutrition.

During recovery from severe wasting, malnourished children gain weight at greatly accelerated rates. To determine if additional zinc added to their basal therapeutic diets increased the retention of lean tissue and stimulated protein metabolism, we studied three groups of children taking either the basal diet alone or the basal diet supplemented with either 76 mumol (5 mg) or 153 mumol (10 mg) Zn/kg diet. The zinc-supplemented children gained similar weight and consumed the same amount of diet as the unsupplemented children. Zinc supplementation resulted in a greater net absorption of nitrogen and a higher rate of protein turnover, as estimated from urinary ammonia 15N enrichment after oral [15N]glycine. We conclude that additional zinc affected the composition of newly synthesized tissue and intermediary nitrogen metabolism.

The exocrine pancreas in kwashiorkor and marasmus. Light and electron microscopy.

Histological sections of pancreas and liver from 65 cases of children dying from childhood malnutrition were reviewed. The extent of pancreatic atrophy and fibrosis was compared with fatty change in the liver. Pancreatic atrophy was common, and often associated with severe fatty change in the liver, but also occurred in marasmic children with scanty liver fat. Pancreatic fibrosis, when present, was only of mild degree. Among 16 patients with marasmus, fibrosis was only seen in one pancreas. Fibrosis was recorded in 8/25 cases of kwashiorkor, and in 7/24 cases diagnosed as marasmic-kwashiorkor. Electron microscopy of the pancreas was performed in seven cases, using tissue collected at immediate autopsy. Atrophy and variable amounts of degranulation of acinar cells were seen. There was often disorganization of the endoplasmic reticulum with intracisternal sequestration. Mitochondrial swelling was consistent with terminal anoxia. Centro-acinar cells were prominent. Some acini were dilated and contained fibrillar material. These findings support the pioneer paper by Blackburn and Vinijchaikul (1969) and underline the importance of pancreatic atrophy in the pathology of protein-energy malnutrition.

Electron microscopy of herpes simplex hepatitis with hepatocyte pulmonary embolization in kwashiorkor.

We report a case of herpes simplex hepatitis in a child with edematous malnutrition. Electron microscopy showed virus in parenchymal cells, with pulmonary embolization of necrotic, infected hepatic cell fragments. Systemic dissemination of herpes simplex may be related both to the profound immunoincompetence associated with kwashiorkor and to a reduction in the circulating and fixed polyanions that normally inhibit viral attachment to cells.

Peroxisomes and the fatty liver of malnutrition: an hypothesis.

Peroxisomes play a role in hepatic beta-oxidation of fat, a process that results in the production of hydrogen peroxide. The fatty infiltration of the liver that occurs in severely malnourished children remains unexplained. We observed an almost total absence of peroxisomes in the hepatocytes of these children. We suggest that lack of available peroxisomes could contribute to the development of fatty liver.

Glycemic response to sucrose-containing mixed meals in diets of children of with insulin-dependent diabetes mellitus.

Our pilot study compared the short-term glycemic effects of a traditional "sucrose free" diet (Suc-Free, 2% total calories from sucrose) to a sucrose-containing diet (Suc-Con, 10% total calories from sucrose) in a clinical research center. Both weighed diets were isocaloric and included 50% carbohydrate, 30% fat, and 20% protein in three meals and three snacks; glucose, fructose, and dietary fiber were identical. Sucrose isocalorically replaced complex carbohydrate at each meal and for the afternoon snack. Ten children (7 to 12 years of age; mean total hemoglobin A1 level 8.9 +/- 0.3%) were randomly assigned, in a crossover design, to one of the two orders (Suc-Free followed by Suc-Con or Suc-Con followed by Suc-Free) for consecutive 2-day diet periods; insulin doses remained constant. Preprandial and postprandial blood glucose levels were measured for each meal and snack (18 measurements per day). To account for baseline differences, we calculated the change in blood glucose levels from baseline to 30 minutes and 1 hour for each meal and snack (mean +/- SEM). No differences were detected between diets. Total area under the glucose response curve (levels measured hourly from 8 AM to 9:30 PM in milligrams per deciliter) was not significantly different for the two diets (Suc-Free 3672 +/- 240; Suc-Con 3574 +/- 285; p = 0.74). No difference in 24-hour urinary glucose levels (measured in grams per day) was detected between the two diets (Suc-Free 35.6 +/- 7.5; Suc-Con 34.5 +/- 7.5; p = 0.84). Incidences of hyperglycemia that required supplemental short-acting insulin and of mild hypoglycemia were similar for both diet periods. Thus, in a controlled setting and during a short study period, children with insulin-dependent diabetes mellitus had a similar glycemic response to diets with and without a moderate amount of sucrose.

The rate of ingestion of Ascaris lumbricoides and Trichuris trichiura eggs in soil and its relationship to infection in two children's homes in Jamaica.

The rate of exposure to geohelminth infection of children living in 2 institutions in Jamaica, West Indies, was estimated from the product of their rates of ingestion of soil and the density of parasite eggs in the environment. The estimated mean rate of egg ingestion was 9-20 Ascaris lumbricoides eggs and 6-60 Trichuris trichiura eggs per year, although the distribution was highly overdispersed so that some individuals had an estimated annual exposure of several hundred eggs. The estimated individual rates of exposure correlated significantly with the observed worm burdens in children at one of the homes, but not at the other. It is suggested that the susceptibility of the children and the distribution of infective stages in the environment may be important in determining the relationship between exposure and the rate of acquisition of infection.