Changing survival and impairment rates at 18-24 months in outborn very low-birth-weight infants: 1984-1987 versus 1980-1983

Outcomes at 18-24 months corrected age of very low-birth-weight infants admitted to our Neonatal Intensive Care Unit in 1984-1987 (period 2) were compared with the outcomes of infants admitted in 1980-1983 (period 1) (total 1357 infants). In the 500-750-g birth-weight subgroup, the survival rate increased from 32 to 54% (p = 0.002). Rates of moderate and severe impairment at 18-24 months (neurosensory deficit, or Bayley corrected mental developmental index < or = 68) in this subgroup decreased from 41 to 15% (p = 0.005), and in those without severe impairment, mean mental Bayley scores in periods 1 and 2 were 84 +/- 18 and 90 +/- 16, respectively (p = 0.20). Analysis after exclusion of small-for-gestational-age infants gave similar results. In the small-for-gestational-age infants of birth weight 500-750 g, the survival rate increased but the impairment rate was unchanged between periods. It is concluded that outcomes improved in 1984-1987 compared with 1980-1983 only for infants with birth weight of 500-750 g.

Rescue from pediatric ECMO with prolonged hybrid intratracheal pulmonary ventilation. A technique for reducing dead space ventilation and preventing ventilator induced lung injury

Hybrid intratracheal pulmonary ventilation (h-ITPV) is a continuous flow ventilatory technique that uses a "reverse thruster" catheter to redirect the flow of gas away from the carina. We report here the use of h-ITPV in a pediatric patient with acute sickle cell chest syndrome who required venoarterial ECMO support because of refractory hypoxemic respiratory failure. Her ECMO course was complicated by air leaks, coagulopathy, cardiac tamponade, and necrotizing tracheobronchitis. She could be weaned from ECMO only by maintaining high pressure conventional ventilatory support. To prevent ventilator induced barotrauma, we initiated h-ITPV and weaned her from ECMO bypass. After 12 days of h-ITPV, with tidal volumes of 2-3 ml/kg at carinal peak inspiratory pressures of 25-30 cm H2O, the air leaks ceased and h-ITPV was discontinued. Dead space ventilation fraction (VD/VT) as low as 0.29 was achieved with this technique. Post-h-ITPV bronchoscopy displayed a dramatic resolution of the necrotizing tracheobronchitis. The patient survived and was discharged from the hospital. We conclude that the use of hybrid ITPV may facilitate weaning from ECMO to low pressure conventional ventilation and prevent the development of pulmonary barotrauma.

Suggested reference ranges in clinical chemistry for apparently healthy males and females of Pakistan

Seven hundred and eighty six apparently healthy males (418) and females (368) aged 0-69 years were randomly selected for estimation of reference ranges of 24 serum analytes at the clinical chemistry laboratory of The Aga Khan University Hospital (AKUH). Of the total study samples, 56% (439/786) were in the paediatric age group (0-14 years) and 44% (347/786) in the adult (15 > or = 60 years) group. Beckman Astra Ideal Autoanalyzer was used for all the estimations. Mean and standard deviations (SD) were calculated for each of the age groups. Reference ranges were calculated following standard methods of the International Federation of Clinical Chemistry (IFCC) and International Committee for Standardization in Haematology (ICSH).

Clonality of T lymphocytes expanded with IL-2 from rheumatoid arthritis peripheral blood, synovial fluid and synovial membrane

The association of rheumatoid arthritis (RA) with particular MHC class II genes suggests that autoantigen-specific T cell clones present in joints could be central to the pathogenesis of the disease. Previous investigations on the clonal diversity of T cells infiltrating the rheumatoid synovial membrane have yielded conflicting results. With the use of Southern blot analysis, we investigated the clonality of rheumatoid T cell lines expanded from peripheral blood, synovial fluid and synovial tissue. From peripheral blood lymphocyte (PBL) of RA patients and healthy normal controls, we also checked the consequences of two different culture conditions on the clonality of these cell lines. From control PBL, we found that in vitro non-specific expansion of non-clonal T cell populations does not create artefactual clonal selection. However, growing T cells in vitro with IL-2 seems to be able to lead to preferential expansion of cells bearing IL-2 receptor (IL-2R). We identified such in vivo activated IL-2-sensitive T cell clones frequently in RA synovial tissue (8/13) and more rarely in synovial fluid and peripheral blood (3/12). One patient presents the same T cell receptor gene rearrangements in synovial membrane of two affected joints. In RA synovial tissue, the frequency of these IL-2-responsive T cells is most prevalent among actively inflamed membranes removed early in the disease process. The role and the relevance to the disease of these IL-2-responsive T cells remain to be elucidated.

Effect of lysine residue modification of ovine luteinizing hormone by heterobifunctional crosslinking reagent SPDP on subunit-subunit association, receptor binding and biological activity

The increasing use of heterobifunctional crosslinking agent in the design of hormone-carrier conjugates for selective targeting or inducing immune response against the hormone has prompted us to study the effect of epsilon-NH2 group modification of oLH-subunit, their recombination, immunoreactivity, receptor binding and biological activity. The epsilon-NH2 groups of oLH alpha and oLH beta subunits were modified by using SPDP. The SPDP modified oLH alpha derivatives hybridize to native OLH beta as judged by RP-HPLC analysis. The sequential modification of alpha and beta subunits led to progressive reduction in immunoreactivity and receptor binding activities. The steroidogenic potential of oLH beta.SPDP.alpha oLH recombinant was relatively comparable. The modification of six or more epsilon-NH2 groups in oLH alpha although recombine fully with native oLH beta but failed to react to anti-oLH antibody. Moreover, steroidogenic activity was also abolished. Introduction up to four SPDP groups in oLH alpha compromised immunological and biological activities but further addition of two more SPDP groups completely abolished antibody reactivity, receptor binding and steroidogenic activity indicating the importance of later two -NH2 groups in the receptor recognition and steroidogenic potential.

Design of liposome to improve encapsulation efficiency of gelonin and its effect on immunoreactivity and ribosome inactivating property

Gelonin, purified from the seeds of Gelonium multiflorum, using cation-exchange and gel-filtration chromatography was characterised for its purity, homogeneity and molecular weight by reverse-phase HPLC (RP-HPLC) and SDS-PAGE analysis. The HPLC purified gelonin was used for entrapment studies in the liposomes. Liposomes were prepared by reverse phase evaporation (REV) technique using three different types of lipid composition in the same molar ratio. The method resulted in 75-80% entrapment efficiency of gelonin in the liposomes. Entrapped and unentrapped gelonin was characterized for physico-chemical, immunochemical and biological properties. The immunoreactivity of entrapped gelonin was fully preserved but the ribosome-inactivating property was slightly inhibited. The method involved mild conditions, highly reproducible and the liposomes produced appeared to be stable for several months. It has important implications in the development of cell type specific cytotoxic agents where a chemical cross-linking is involved which significantly inhibits both immunoreactivity and ribosome-inactivating ability of the toxin.

A model for formulation of protein assay

The principle of the protein assay using the reaction of an alkaline copper-protein complex with the Folin-Ciocalteu phenol reagent has been investigated. In contrast to the long-established Lowry method, a stable and rapid protein assay is developed without a buffering agent in alkaline copper solution. In the absence of a buffering agent, the reaction pH drops relatively rapidly and moves the reaction toward a more stable pH. When the reaction of alkaline copper-protein complex with Folin-Ciocalteu reagent is started at around pH 11.7, the reaction color absorbance reaches a plateau in approximately 10 min and remains stable to allow a reliable measurement of the absorbance. In the absence of the buffering agent sodium carbonate, the alkaline copper solution is also stable for months. The principle of the protein assay is presented as a model that can be used to formulate protein assays of desired specification.

Sterilization of sparingly soluble compounds for cell culture use

A method is presented for the successful decontamination of sparingly soluble pteridine derivatives by microwave irradiation. The method is nondestructive, rapid and effective in eliminating contamination.

Evaluation of adjuvanticity of promising new synthetic MDP analogues

A series of nor-MDP analogues were evaluated for adjuvanticity in rodents using beta hCG-TT conjugate as the antigen. Of these, one compound, N-acetylnor-muramyl-L-N-methylalanyl-D-isoglutamine octylamide (nor-MDP octylamide (N-Me-Ala] was found to be effective. This compound, formulated with beta hCG-TT in water-in-oil emulsion and administered to rodents, significantly enhanced the anti-hCG response. The anti-hCG titers induced were three-fold higher than that of control formulation. Moreover, inclusion of this compound in the first injection only gave adequate levels of antibodies to the hormone which persisted longer in the blood circulation. Effectiveness of antibodies in neutralizing hCG was tested in vitro by the mouse Leydig cell bioassay. Biological vs. immunological binding capacities (B/I ratio) were compared. The results suggest that nor-MDP octylamide (N-Me-Ala) will be useful as an adjuvant for human vaccines.

Acute lower respiratory tract infections in hospitalized patients with diarrhea in Dhaka, Bangladesh

This study focused on 401 children less than 5 years old who were hospitalized with acute lower respiratory tract infection (ALRI) and diarrhea in Dhaka, Bangladesh, and who were investigated for the presence of both bacterial and viral respiratory tract pathogens as well as for selected diarrheal pathogens. The most common manifestations of ALRI were pneumonia (374 cases), bronchiolitis (12 cases), and tracheobronchitis (11 cases). The majority (77%) of the illnesses were in children less than 2 years of age, and 88% of the children were malnourished. A respiratory tract pathogen was identified in 30% of the patients, and a diarrheal pathogen was identified in 34%. The overall case-fatality rate in children with ALRI and diarrhea was 8%. The case-fatality rate was 14% in children with bacterial pneumonia and diarrhea, 3% in those with viral pneumonia and diarrhea, and 14% in malnourished children with shigellosis and ALRI. The most common respiratory tract pathogens were respiratory syncytial virus, Streptococcus pneumoniae, influenza viruses, and Haemophilus influenzae type b.

Acute lower respiratory tract infection due to virus among hospitalized children in Dhaka, Bangladesh

The nature of acute lower respiratory tract infection (ALRI) in hospitalized children and of the associated viral agents was assessed in a study of 601 children less than 5 years old over a 24-month period. Of these children, 80% were less than 24 months of age and the ratio of boys to girls was 1.7:1. Pneumonia (86.5% of cases) was the most frequently observed clinical manifestation. Shedding of virus was detected in 21.1% of the children; the highest rate occurred in infants 0-5 months old (27%) as compared with a rate of only 12.5% in children 25-60 months old. Virus was detected in 33.3%, 32.8%, 21.2%, and 20% of the cases of tracheobronchitis, bronchiolitis, pneumonia, and croup, respectively. Among the viruses detected, 78% were respiratory syncytial virus (RSV) (91% of infections with this virus occurred in children less than 2 years old) and 14.4% were influenza virus types A and B. Of the RSV infections, 61% occurred in infants less than 1 year old. The case-fatality rate was 6.8% overall and was 4.8% in virus-associated cases. No consistent pattern of seasonal occurrence of viral infections was discerned. RSV was detected throughout the year, with increased prevalence from January to April.

Serum alkaline phosphatase in apparently healthy Karachi population

Serum alkaline phosphatase (AP) was estimated in a total of 786 (418 males and 386 females) apparently healthy people aged between 1-75 years selected randomly from a sample of the Karachi population. Reference ranges for AP level were obtained for the males and females stratified into ten successive age groups. The study population was also divided into two main age groups, a paediatric aged between 1-14 years and an adult group aged between 15 to over 50 years to see if the mean AP levels differ significantly between the two groups. Mean AP level for the male paediatric age group was 225 IU/L, significantly higher (P less than 0.005) than those of the male adult mean level of 83 IU/L. Similarly the mean AP levels for the paediatric female age group was 205 IU/L significantly higher (P less than 0.005), compared to the mean AP level of 67 IU/L obtained for the female adult age group.

Functional morphology of testis and its excurrent ducts in rats immunized with synthetic luteinizing hormone releasing hormone conjugated to tetanus toxoid

The effects of active immunization against luteinizing hormone releasing hormone (LHRH) on the testis and its excurrent ducts in rats were studied using a synthetic LHRH peptide conjugated to tetanus toxoid (TT), with or without an adjuvant. The study demonstrated that LHRH-TT given alone did not elicit an appreciable immune response and that its immunogenicity could be enhanced by administration with an adjuvant, such as species-specific IgG or SPLPS. The anti-LHRH antibody response showed a corresponding regressive effect on the morphology of the testis and its excurrent ducts. The functional involution of the testis was reflected in the form of a block in spermatogenesis and the lowering of testosterone production; the basic structural organization of the testicular components was, however, maintained. Epididymal ducts displayed rather drastic atrophic changes, indicating that prolonged immunization may result in irreversible damage to the excurrent ducts and could, therefore, adversely affect the restoration of fertility even after the return of testicular function following decline in the immune response against LHRH. This could be an important consideration if LHRH immunization is to be used for male contraception.

Antibody response and characteristics of antibodies in women immunized with three contraceptive vaccines inducing antibodies against human chorionic gonadotropin

Data are presented on antibody titers generated in 88 women immunized with three formulations of antihuman chorionic gonadotropin (hCG) vaccine, namely, beta-hCG (formulation B); beta-hCG associated with alpha-subunit of ovine luteinizing hormone (LH) (formulation A) and beta-hCG + beta-ovine LH (formulation M), each linked to tetanus toxoid and cholera toxin chain B as carriers. Each formulation was tested at two dose levels (100 and 500 micrograms). All women without exception developed anti-hCG antibodies having hCG-binding capacity above 20 ng mL-1 (0.5 nM), a level considered to be the threshold for prevention of pregnancy. Formulations A and B gave relatively better immunogenic response in human subjects than M. In each case, the antibody response was reversible. The mean duration of response above 20 ng was 35 to 37 weeks for formulation A, 34 weeks for B, and 17 to 20 weeks for M. Antibodies induced by three formulations of the vaccine had high-affinity (Ka 10(9)-10(10)M-1) for binding with hCG. They were devoid of cross-reaction with human follicle-stimulating hormone and thyroid-stimulating hormone but, as expected, cross-reacted with human LH. Antibodies were competent to block the hCG induced ovarian hyperemia.

Stability of an antifertility vaccine consisting of gonadotropin subunits linked to tetanus toxoid

The shelf life and thermal stability of an antifertility vaccine, in which gonadotropin subunits are linked to carriers such as tetanus toxoid and cholera toxin chain B and has successfully completed phase-I clinical trials at five centres in India, was studied. The vaccine adsorbed on alum was stored at three temperatures, 4 degrees C, room temperature (20-30 degrees C) and at 40 degrees C, for a period of up to 1 year. The human chorionic gonadotropin (hCG) binding capacity of antibodies (peak titres) induced in rodents by the vaccine after 6 months of storage at 40 degrees C and at room temperature were 1430 +/- 201 (mean +/- s.e.m.) and 1291 +/- 152 ng ml-1 respectively as compared to 1075 +/- 185 ng ml-1 for the vaccine stored at 4 degrees C. The difference was not statistically significant. After 12 months of storage, the immunogenic properties of the vaccine were nearly the same irrespective of the temperature at which the vaccine was kept. The findings show that the vaccine adsorbed on alum can withstand storage up to at least one year at room temperature and at 40 degrees C. These observations have implications for the current thoughts on storage of tetanus toxoid and diphtheria toxoid at 4-8 degrees C, the two vaccines widely used in immunoprophylaxis, and suggest that similar investigations on these vaccines as cold chain facilities are not universally available in developing countries.

Human liver GTP cyclohydrolase I: purification and some properties

Human liver guanosine triphosphate (GTP) cyclohydrolase I has been purified more than 1,700-fold to what appears to be homogeneity. The active enzyme complex has an estimated molecular weight of 453,000 +/- 11,500 by gel filtration chromatography. It consists of a polypeptide of 149,000 +/- 4,000 mol wt by SDS-polyacrylamide gel electrophoresis. The activity of the enzyme is heat stable and is inhibited by di- and trivalent cations. The enzyme has an optimum pH of 7.7 in sodium phosphate buffer. It uses GTP as a sole substrate, with a Km of 116 microM.

Semisynthetic anti-LHRH vaccine causing atrophy of the prostate

A modified luteinizing hormone releasing hormone (LHRH) analog (D-lys)6 was synthesized and linked to epsilon-amino caproic acid at the 6th position. The free amino group thus generated was used for conjugation to diphtheria toxoid. Immunogenicity and bioefficacy studies of this conjugate vaccine were carried out in rodents. All immunized animals produced antibodies reactive with native LHRH. A gradual decline in testosterone levels accompanied the rise in anti-LHRH titers. On necropsy, after 10 weeks, a significant reduction in the relative weights of testes and accessory sex organs was noticed. Of particular significance was the marked atrophy of the prostate, indicating a possible therapeutic application of this vaccine in the treatment of androgen-dependent carcinoma of the prostate.

Inhibition of GTP cyclohydrolase I by pterins

Pterins inhibit rat liver GTP cyclohydrolase I activity noncompetitively. Reduced pterins, such as 7,8-dihydro-D-neopterin, (6R,S)-5,6,7,8-tetrahydro-D-neopterin, 7,8-dihydro-L-biopterin, (6R)-5,6,7,8-tetrahydro-L-biopterin, L-sepiapterin, and DL-6-methyl-5,6,7,8-tetrahydropterin are approximately 12-times more potent as inhibitors than are oxidized pterins, such as D-neopterin, L-biopterin, and isoxanthopterin. They are also 12-times more potent than folates, such as folic acid, dihydrofolic acid, (+/-)-L-tetrahydrofolic acid, and aminopterin. The Ki values for 7,8-dihydro-D-neopterin, 7,8-dihydro-L-biopterin, and (6R)-5,6,7,8-tetrahydro-L-biopterin are 12.7 microM, 14.4 microM, and 15.7 microM, respectively. These results suggest that mammalian GTP cyclohydrolase I may be regulated by its metabolic end products.