A bacteriological study in hospitalized children with pneumonia

A total of 110 consecutive hospitalized children with severe lower respirator tract infection were studied with the aim of determining the main bacterial pathogens responsible. Of these, 57 were classified as severe pneumonia and 53 as very severe pneumonia. Streptococcus pneumoniae was the most common organism identified in 24.6% and 32.1% of cases of severe and very severe pneumonia, respectively, followed by Haemophilus influenzae type b, which was seen in 17.5% and 20.8%, respectively. The highest diagnostic yield was with the latex particle agglutination test on serum and urine. Blood culture was positive in only ten of the 110 children. No difference was found between the aetiological agents identified in severe and very severe cases of pneumonia. Therefore, the use of different parenteral antibiotics for two clinically defined groups of pneumonia, as recommended by WHO in their standard case management guidelines for the ARI control programme, does not seem necessary.

Tumor-associated sialylated antigens are constitutively expressed in normal human colonic mucosa

Immunohistochemical studies have indicated that sialylated carbohydrate antigens such as sialyl-Tn, sialyl-Le(a), and sialyl-Le(x) are expressed in a tumor-associated fashion in human colon. Since sialic acid residues are O-acetylated more extensively in normal colonic epithelium than in colon cancer cells, we examined whether deacetylation of colonic tissues might enable monoclonal antibodies to recognize these tumor-associated sialylated antigens. In normal colon, deacetylation turned most cases (82%) positive with anti-sialyl-Tn mAb TKH2; and in colon cancers, it increased the number of TKH2-positive cells. Sialyl-Le(a) and sialyl-Le(x) detection was also increased after deacetylation of normal and malignant colonic tissues so that the frequency of positive cases in normal tissues was similar to that in the cancers. However, in the stomach and pancreas, the same treatment rarely increased the detection of the sialylated epitopes in normal or cancerous tissues. Thus, the same sialylated epitopes can be expressed in a tumor-associated fashion by different mechanisms in different gastrointestinal organs; in the colon, these antigens are constitutively expressed and O-acetylated, whereas in the upper gastrointestinal tract, they are rarely O-acetylated, suggesting that other mechanisms such as differences in glycosylation account for the cancer-associated expression.

Testosterone deficiency and extreme retardation of puberty in homozygous sickle-cell disease

Homozygous sickle-cell (SS) disease is associated with retardation of physical and sexual development but most Jamaican SS children commence their adolescent growth spurt before 16 years of age. Analysis of growth data from children in the Jamaican Cohort Study noted extreme growth retardation, defined as absence of the adolescent growth spurt and pre-pubertal sexual development (Tanner stage 1 or 2) at age 16 years, in 8/52 (15%) SS boys. These and two boys from the general sickle-cell clinic with a similar growth pattern provided a study group of 10 boys who were investigated for a possible endocrine explanation for their extreme retardation of physical maturation. A sub-optimal testosterone response (< 10 nmol/l) to human chorionic gonadotrophin and an exaggerated gonadotrophin response to gonadotrophin hormone releasing hormone was consistent with poor testicular function in 5 boys. Retardation of adolescent growth and development is common in boys with SS disease but, when extreme, requires early investigation to identify potentially correctable mechanisms.

Acceleration in linear growth after splenectomy for hypersplenism in homozygous sickle cell disease

Chronic hypersplenism in homozygous sickle cell (SS) disease markedly increases haemolysis and the resulting erythropoietic expansion is likely to have a high metabolic cost. Splenectomy for hypersplenism in SS disease is followed by highly significant changes in haematological indices and an increase in height, but not weight, velocity. This pattern is similar to that observed in the trichuris dysentery syndrome after treatment, and differs from the increases in both height and weight velocity that follow nutritional supplementation of severely malnourished children. It is postulated that accelerated linear growth after the reduction in erythropoietic stress may implicate a specific nutrient deficiency in hypersplenic children with SS.

Host-cell reactivation of reporter genes introduced into cells by adenovirus as a convenient way to measure cellular DNA repair

In order to conveniently measure cellular DNA repair in immortalized and primary human cells we have combined the features of high cellular infectivity of adenovirus (Ad) with that of host-cell reactivation (HCR) of ultraviolet light (UV)-damaged reporter genes. We show that Ads having either the cat (chloramphenicol acetyltransferase) or seap (secreted alkaline phosphatase) reporter gene under control of a strong constitutive promoter can be used to measure relative levels of DNA repair by HCR. Most importantly, the SEAP assay allows for a convenient, inexpensive, and sensitive colorimetric microtiter assay. Only a few steps are involved and it is possible to process many samples simultaneously in a relatively short time, which is not as easily done with other reporter gene assays. Furthermore, we show that co-infection of UV-damaged SEAP Ad with an Ad carrying a prokaryotic repair gene significantly increased the HCR levels in xeroderma pigmentosum cells. The Ad gene delivery system, and the SEAP assay in particular, should simplify existing HCR assays considerably. By using non-lytic Ad as a vehicle it should be possible to quantitatively introduce normal or dominant negative mutant DNA repair genes into bulk cell populations for DNA repair studies.

Delayed adolescent growth in homozygous sickle cell disease

Analysis of the growth abnormalities in sickle cell disease has been limited by the lack of longitudinal observations in individuals, and by an inability to quantitate the observed patterns. To investigate the timing and pattern of the adolescent growth spurt, longitudinal observations of height from the Jamaican cohort study were fitted to a mathematical model of growth (Preece-Baines model 1). The study included 44 children with homozygous sickle cell (SS) disease, 44 age and sex matched subjects with sickle cell haemoglobin C (SC) disease, and 44 age and sex matched controls with normal (AA) haemoglobin. Compared with AA controls, the onset of the adolescent growth spurt was delayed in SS disease by 1.4 years (95% confidence interval 0.8 to 2.0) with no significant sex difference. The age at peak height velocity was delayed by 1.6 years (0.9 to 2.3) in SS compared with AA subjects but the adolescent growth of SS children was otherwise normal and there was no difference in the attained height by age 17.9 years. The growth spurt was not delayed in SC disease. The age at menarche in girls with SS disease (mean (SD) 15.4 (1.3) years) was significantly later than girls with SC disease (13.7 (1.7) years) and those with AA haemoglobin (13.1 (1.3) years) but these genotype differences were no longer significant after controlling for the delay in the adolescent growth spurt. The normally coordinated but slightly delayed pattern of growth and normal adult heights suggests a good prognosis for adolescent growth delay in SS disease. Most children with SS disease can therefore be reassured on the outcome of retarded adolescent growth.

The painful crisis of homozygous sickle cell disease: clinical features

The details of onset, perceived precipitating factors, associated symptoms, and pain distribution in the painful crisis of homozygous sickle cell (SS) disease have been prospectively recorded in 183 painful crises in 118 patients admitted to a day-care centre in Kingston, Jamaica. Painful crises developed most frequently between 3 p.m. and midnight, most commonly affected patients aged 15-29 years, affected the sexes equally, and were not obviously influenced by menstrual cycle. Of the perceived precipitating factors, skin cooling occurred in 34%, emotional stress in 10%, physical exertion in 7%, and pregnancy in 5% of women of child-bearing age. Cold as a precipitant was not less common in patients with more subcutaneous fat. Pain affected the lumbar spine in 49%, abdomen in 32%, femoral shaft in 30%, and knees in 21%. There was a highly significant excess of bilateral involvement in limb and rib pain. Recurrent painful crises occurred in 40 patients but showed no evidence of involving similar sites on successive occasions. Abdominal painful crises were associated with abdominal distention in 18 (31%) and with referred rib pain in a further 15 (26%) of crises. Fever was common even in apparently uncomplicated painful crises, suggesting that fever is characteristic of the painful crisis itself and not necessarily indicative of infection. Following investigation and treatment in a day-care centre, over 90% of patients returned home.

Automatic Analysis, Theme Generation, and Summarization of Machine-Readable Texts

Vast amounts of text material are now available in machine-readable form for automatic processing. Here, approaches are outlined for manipulating and accessing texts in arbitrary subject areas in accordance with user needs. In particular, methods are given for determining text themes, traversing texts selectively, and extracting summary statements that reflect text content.

Development of second generation monoclonal antibodies recognising Lewisy/b antigen by anti-idiotypic immunisation

Five new monoclonal antibodies (Mabs) recognising the Lewisy/b hapten of the IgG isotype have been produced following immunisation with rat anti-idiotypic antiserum to C14, an IgM Lewisy/b hapten Mab and boosting with C14gp200 antigen. They have the same fine specificity as the original Mab binding to a cell surface and secreted antigen preferentially expressed by colorectal tumour cells.

The clinical significance of serum transferrin receptor levels in sickle cell disease

Serum transferrin receptor (TfR) levels were measured in 182 children with homozygous sickle cell (SS) disease, 47 with sickle cell-haemoglobin C (SC) disease and 41 normal (AA) controls on their eighth birthday. Highly significant elevations occurred in SS compared to SC disease and in SC disease compared to AA controls. Females had higher levels than males in controls but lower levels than males in SS and SC disease. In SS disease, serum TfR levels tended to rise with age from 2 to 8 years, the change within individuals correlating with a change in reticulocyte count (r = 0.38, P = 0.017) and fall in fetal haemoglobin levels (r = -0.51, P = 0.004). Serum TfR levels did not change with infection or painful crisis but were markedly elevated in hypersplenism and fell following splenectomy in these subjects. In the aplastic crisis, serum TfR levels tended to rise following clinical presentation and then fall, reflecting the reticulocyte counts. These observations are consistent with serum TfR levels being a useful indicator of the degree of erythropoietic expansion in sickle cell disease.

Is there an acute-phase response in steady-state sickle cell disease?

Metabolic and serum changes during steady-state homozygous sickle cell (SS) disease are consistent with an acute-phase response and raise the possibility that inflammation occurs in SS disease even during the steady state. To test this hypothesis, we measured concentrations of acute phase reactants in patients with SS disease, in patients with sickle cell haemoglobin C (SC) disease, and in normal (AA) control subjects. The concentrations of C-reactive protein and serum amyloid A were increased above 10 mg/L and 5 mg/L, respectively (our definition of an acute-phase response) in 18% (26/143) of subjects with SS disease even when they were symptom free, in 17% (6/35) of subjects with SC disease, and in 1% (1/80) of AA controls (p < 0.001). We suggest that subclinical vaso-occlusion may generate a covert inflammatory response and that the cytokine mediators of this response may contribute to the metabolic abnormalities and growth failure in sickle cell disease.

Ionizing radiation target groups of band 3 inserted into egg lecithin liposomes as determined by Raman spectroscopy

The purified integral membrane protein, band 3, from human erythrocytes was inserted into egg lecithin liposomes. The insertion of band 3 was determined from thermal transition data from the analysis of the C--H stretching region bands recorded at temperatures from 25 to -22 degrees C. Raman spectra show that band 3 considerably broadens and lowers the thermal transition of egg lecithin liposomes, suggesting the insertion of band 3. The band 3-inserted liposomes were irradiated with gamma-rays (40 Gy) and the radiation target groups were determined by the analysis of the structural sensitive Raman bands in the 1600-1700 cm-1 (amide I), 1200-1300 cm-1 (amide III) and 550-1030 cm-1 (side chain amino groups) regions. The radiation-sensitive groups as identified from Raman spectra in the region 550-1030 cm-1 are tyrosines and cysteines. The radiation-induced changes in the secondary structure were determined from amide I and III bands. Quantitative estimation using the curve fitting method shows that band 3 contains 44% total helix, 48% beta strand and 8% undefined plus turns (error +/- 4%). The secondary structure changes to 35% total helix, 42% total beta-strand and 23% turned and undefined upon irradiating band 3 containing liposomes. We suggest that ionizing radiation preferably damages tyrosine and cysteine side chain residues and reduces the amount of alpha-helical configuration of band 3.

Resting metabolic rate in homozygous sickle cell disease

The resting metabolic rate in 20 patients with homozygous sickle cell (SS) disease was 19% higher than in 20 age- and sex-matched control subjects with a normal hemoglobin genotype (AA). The difference was not accounted for by differences in lean body mass. It is postulated that this increased energy expenditure reflects the energy expenditure of erythropoietic hyperplasia and leads to a marginal nutritional state that may contribute to the abnormal growth in SS disease.

Expression of sialylated Lewis(x) antigen in chronic and neoplastic liver diseases

Phenotypic expression of sialylated Lewis(x) antigen by means of the monoclonal antiserum SNH3 was studied in 87 livers, which included normal and steatotic livers and livers with chronic persistent and chronic active hepatitis, alcoholic hepatitis, allograft rejection, focal nodular hyperplasia, hepatocellular carcinoma, cholangiocarcinoma, metastatic carcinoma, cirrhosis of various causes (autoimmune, alcoholic, viral, drug induced, Wilson's disease, and primary biliary cirrhosis). The biotin-streptavidin-peroxidase method was used on formaldehyde-fixed, paraffin-embedded sections. Sialylated Lewis(x) antigen was not demonstrated in normal livers. Hepatocellular expression in a diffuse or perinodular honeycomb pattern was seen in cirrhosis, irrespective of cause. Sialylated Lewis(x) antigen was also observed in hepatocytes around metastatic carcinoma in the absence of inflammation, cirrhosis, or regeneration. Some bile ductules, most likely ductular hepatocytes, but not bile ducts, expressed sialylated Lewis(x) antigen. Sialylated Lewis(x) antigen was seen diffusely in fibrolamellar hepatocellular carcinoma, focally in other hepatocellular carcinomas, and either focally or diffusely in cholangiocarcinomas.

Reactivity profiles of leukemic myeloblasts with monoclonal antibodies directed to sialosyl-Le(x) and other lacto-series type 2 chain antigens:absence of reactivity with normal hematopoietic progenitor cells

We investigated the expression profiles of lacto-series type 2 antigens in hematopoietic cells and their progenitors, in comparison with leukemic leukocytes. Reactivity profiles of various anti-type 2 chain monoclonal antibodies (MoAbs) with leukemic blasts from 12 patients with acute myeloblastic leukemia (AML) and those from two patients with acute unclassified leukemia (AUL) show that anti-sialosyl-Le(x) MoAb SNH3 reacted strongly with greater than 95% of leukemic blast leukocyte populations from all patients (14 of 14). Another anti-sialosyl-Le(x) MoAb, FH6, showed less reactivity than SNH3 (12 of 14 patients), while anti-Le(y) MoAb AH6 showed reactivity with only 8 of 14 patients. On the other hand, none of the anti-type 2 chain MoAbs reacted with CD34+ normal adult bone marrow (BM) mononuclear cells obtained independently from three healthy volunteers. MoAb SNH3, but not FH6 or AH6, showed complement-mediated cytotoxicity to leukemic blasts from these patients, as well as to myelogenous leukemia cell line HL60. Colony-forming unit granulocyte-macrophage (CFU-GM), but not burst-forming unit-erythroid (BFU-E), was incompletely inhibited by treatment of normal BM mononuclear cells with SNH3 and complement. The absence of type 2 chain antigen expression in hematopoietic progenitor cells and in in vitro hematopoietic colonies (CFU-GM and BFU-E) strongly suggests that application of anti-carbohydrate MoAbs, particularly anti-sialosyl-Le(x) could be useful for elimination of leukemic myeloblasts infiltrating in BM, for purging of leukemic blasts in BM, and for facilitation of autologous BM transplantation.

Low levels of the pesticide, delta-hexachlorocyclohexane, lyses human erythrocytes and alters the organization of membrane lipids and proteins as revealed by Raman spectroscopy

We studied the nature of the interaction of delta-hexachlorocyclohexane (delta-HCCH), a pesticide having a stereoisomeric structure similar to inositol, with red blood cells. Cell survival data, measured as percent of hemoglobin released by delta-HCCH, show that the cell lysis increases with post exposure time. delta-HCCH at 55-60 micrograms/ml causes about 70% cell lysis after 24 h of exposure. The nature of interaction of delta-HCCH with membrane components was evaluated by studying the thermotropic transitions and protein structure of ghosts using Raman spectroscopy. Control ghosts show transitions with onset/completion temperatures 30 degrees C/38 degrees C (high temperature transition) and 3 degrees C/10 degrees C (middle temperature transition) when monitored by the I2935/I2850 ratio. The interaction of delta-HCCH drastically broadens the high temperature transition and shifts it to the temperature range of 10-29 degrees C. The plots of (I2880-90/I2850) vs. temperature show two transitions for control ghosts, one extending from -10 degrees C to 3 degrees C (lower temperature transition) and the other from about 7 degrees C to about 15 degrees C (middle temperature transition). Ghosts lysed with delta-HCCH shows only a single and a very broad transition in the range of about -3 degrees C to about 15 degrees C. These changes in the thermal transition properties suggest that delta-HCCH alters lipid and lipid-protein phases of erythrocyte membranes. The comparison of Raman spectra in the amide I and III regions of erythrocyte ghosts and purified band 3 with several amidated compounds reveals that cytoskeleton proteins contain highly amidated residues (probably glutamine and asparagine). The interaction of delta-HCCH with erythrocytes drastically alters the environment of these amidated residues indicating the involvement of cytoskeleton proteins. We conclude that the interaction of delta-HCCH with red blood cells disrupt membrane structure and change the environment of cytoskeleton proteins that could cause cell lysis.

Induction of alpha-N-acetylgalactosamine-O-serine/threonine (Tn) antigen-mediated cellular immune response for active immunotherapy in mice

A block in carbohydrate chain elongation of O-glycosylated mucins results in accumulation of alpha-GalNAc O linked to serine or threonine (Tn antigen) in a large percentage of human adenocarcinomas. Immunization of mice with desialylated ovine submaxillary mucin (A-OSM), which contains a large concentration of Tn antigen, provided protection against challenge of a highly invasive Tn expressing syngeneic mouse mammary tumor, TA3-Ha. A similar protective effect was not observed in mice immunized with the deglycosylated mucin or irradiated TA3-Ha cells. Immunization with A-OSM but not with deglycosylated mucin resulted in high anti-Tn antibody response in mice. A-OSM induced in vitro proliferation of T-lymphocytes obtained from mice preimmunized with A-OSM or irradiated TA3-Ha cells. This antigen-specific T-cell response was significantly lower if lymphocytes were stimulated with either the deglycosylated or sialylated form of mucin. A-OSM stimulation induced primarily a CD4+ T-cell population, and these cells secreted interleukin 2 in a dose-dependent fashion. A-OSM was also able to induce delayed-type hypersensitivity in mice in response to footpad injections with irradiated TA3-Ha cells. These studies indicate that Tn antigen presented on a protein backbone is capable of providing cellular immunity and protection against tumor in mice.

Empyema of gallbladder in a child with homozygous sickle-cell disease

A 13-year-old boy with homozygous sickle-cell (SS) disease followed from birth in a cohort study of sickle-cell disease developed empyema of the gallbladder after a known 3-year history of gallstones. At this age, gallstones occur in 30% of cohort study children with SS disease but this is the first patient with specific symptoms.

Molecular changes in carbohydrate antigens associated with cancer

Oncogenic transformation is often associated with aberrant glycosylation in experimental and human tumors. The carbohydrate epitopes, resulting either from incomplete synthesis or neosynthesis, accumulate in high density, possibly in a novel conformation, at the tumor cell surface. A variety of monoclonal antibodies have been developed that recognize tumor-associated carbohydrate antigens and their aberrant organization at the cell surface. These carbohydrate epitopes and the antibodies specific to these structures are being exploited to develop novel diagnostic tools and therapeutic strategies for cancer.

Drug targeting in Leishmania donovani infections using tuftsin-bearing liposomes as drug vehicles

The efficacy of sodium stibogluconate against Leishmania donovani infections was markedly enhanced by encapsulating this drug in tuftsin-bearing liposomes. Also, pretreatment of the animals with these liposomes (free of drug) rendered them resistant to this infection, possibly by activating the host's macrophages. These results demonstrate that tuftsin-bearing liposomes besides delivering the drug to the target cells could also enhance the nonspecific resistance against infections, thus offering an additional advantage over the use of tuftsin-free liposomes as drug carriers in leishmania therapy.

Antibody-mediated targeting of differentiation inducers to tumor cells: inhibition of colonic cancer cell growth in vitro and in vivo. A preliminary note

A differentiation inducer (sodium butyrate) encapsulated in liposomes that are in turn covalently linked to anti-Lex monoclonal antibody, SH1 (IgG3 isotype), was successfully targeted to human colonic adenocarcinoma HRT-18 and HT29 cells expressing Lex antigen in vitro as well as in vivo in athymic nu/nu mice. Tumor cell growth was significantly inhibited and was associated with changes in cell morphology and increases in membrane-bound alkaline phosphatase and gamma-glutamyltranspeptidase, indicating the occurrence of butyrate-induced differentiation.

Serum haloperidol concentration and choreiform movements in Huntington's disease

The relationship between serum haloperidol concentration and improvement in abnormal movements was investigated in 20 adult Huntington's disease (HD) patients. Serum samples and assessments of severity of chorea were simultaneously obtained from each patient. Data were obtained prior to and at one or more doses following the initiation of haloperidol in ten patients. Serum was analyzed for haloperidol by two different methods, gas chromatographic/mass spectrometric (GC/MS) and radioreceptor (RR) assays. Steady-state serum haloperidol concentrations (GC/MS) of 0.5 to 24 ng/ml were observed following administration of doses of 1 to 40 mg/d and varied markedly between patients. Only results from the GC/MS assay were used for examining relationships with dose and clinical response because of insensitivity of RR assay. Significant improvement of abnormal movements, greater than 30% from baseline, occurred at serum concentrations between 2 and 5 ng/ml, which corresponded to doses of 1.5 to 10 mg/d. Further improvement in abnormal movements at serum concentrations above this range was minimal.