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Biomedical subjects

N A Mir

Publications and source records attributed to N A Mir.

At least 19 recordsLinked to original sources
PubMed1999

Effect of superficial scald suppression by diphenylamine application on volatile evolution by stored Cortland apple fruit.

Cortland apple fruit (Malus x domestica Borkh.) stored for 120-140 days in air at 0 degrees C were warmed to 22 degrees C and held for 8 days. A portion of the fruit was dipped in a solution of diphenylamine (DPA) at harvest to prevent scald development. Scald occurred only in those fruit not treated with DPA, and its development was accelerated after transfer to 22 degrees C. Ester production from apple fruit tended to increase from day 0 to day 6 of poststorage holding and declined thereafter in both treatments. However, ester production in scald-developing fruit was reduced by approximately 50%. The reduction in volatile production remained relatively constant during the rapid development of scald symptoms. Furthermore, the reduction in volatile production appeared to be independent of respiration and ethylene production. Production of esters derived from hexanol was most reduced in fruit developing scald, with hexyl 2-methylbutanoate production being reduced approximately 15-fold. Interestingly, the production of methyl butanoate was detected only in scalding fruit. alpha-Farnesene production in fruit developing scald was reduced 43% compared with DPA-treated fruit. In contrast, the primary volatile oxidation product of alpha-farnesene, 6-methyl-5-hepten-2-one (MHO), was present only in fruit developing scald. The data suggest that inhibition of ester production may occur as a result of the physiological changes associated with susceptibility to, rather than expression of, scald symptoms.

Diphenylamine↗
PubMed1999

Relationship between ethylene response manipulation and volatile production in Jonagold variety apples.

The ripening of Jonagored Jonagold apple fruit (Malus x domestica Borkh.) during development was manipulated with preharvest applications of ReTain or a combination of ReTain plus Ethrel. The fruits, harvested preclimacteric at approximately the same stages of maturity, were stored in refrigerated air (RA) for 45 days or in controlled atmosphere (CA) for 180 days at 0 degrees C. Volatile evolution, ethylene production, and respiration of stored fruit were studied during poststorage holding at 22 degrees C. ReTain reduced volatile production by 19%, but application of Ethrel to ReTain-treated fruit increased production to control levels. The inhibition of volatile production by ReTain appears to be independent of respiration but may be related to the ethylene-producing capacity of the fruit. Although ReTain reduced flavor-related volatile esters, it did not affect levels of the compound responsible for the typical spicy flavor in Jonagored Jonagold fruit, 4-methoxy-2-propenylbenzene. The CA-stored fruit had a much reduced production of volatile compounds compared to RA-stored fruit, with more discernible effects in ReTain-treated fruit. Ethrel application to ReTain-treated fruit improved the volatile production intermediate between the ReTain alone and control in CA-stored fruit. The data collectively suggest that ReTain may have some promise for better scheduling of harvest of apples with no appreciable loss in RA-stored fruit quality. Reduction in production of alpha-farnesene by ReTain may also reduce the potential for scald development in CA-stored fruit.

Chromatography, Gas↗
PubMed1994

Gamma delta T lymphocytes and proinflammatory cytokines in bacterial meningitis.

BACKGROUND: Patients with bacterial meningitis have a T-cell defect and impaired cytokine production. METHODS: The phenotype and percentage of circulating alpha beta and gamma delta T-cell receptor-bearing lymphocytes were determined from patients with bacterial meningitis (Haemophilus influenzae, Streptococcus pneumoniae, and Neisseria meningitidis), patients with bacterial infection but without meningitis, and healthy control subjects by a monoclonal antibody staining method. The in vitro production of cytokines, interleukins (IL-2, IL-6), interferon-gamma and tumor necrosis factor-alpha was measured by the bioassay or ELISAs. RESULTS: The percentage of circulating gamma delta T cells with a CD3+CD4+CD8- phenotype was significantly (p < 0.001) increased in all patients with bacterial meningitis compared with patients with bacterial infection and healthy control subjects. The CD3+ gamma delta T cells from patients with meningitis produced highly elevated levels of two proinflammatory cytokines, tumor necrosis factor-alpha and IL-6. However, interferon-gamma production was enhanced by CD3+ alpha beta T cells. CONCLUSION: The increased percentage of circulating T-cell receptor gamma delta T cells and their in vitro production of tumor necrosis factor-alpha and IL-6 cytokines may play an important role in the pathogenesis and inflammatory response in bacterial meningitis.

Antibodies, Monoclonal↗
PubMed1992

Perinatal mortality in high risk pregnancy: a prospective study of preventable factors.

The present study was undertaken to identify the preventable factors operative in high fetal and neonatal losses. Over a period of one year, of total of 1,600 consecutive deliveries, 1,107 were considered to be at-risk: there were 33 fetal and 31 early neonatal deaths with an overall perinatal mortality rate of 40/1,000 births. Perinatal mortality was higher in mothers who had received inadequate antenatal care and/or with bad obstetric history. Major maternal and obstetric factors associated with a high PMR were: advancing maternal age and parity, antepartum hemorrhage, diabetes, anemia, instrument and vaginal breech delivery. Overall cesarean section rate was 16.9%. Infants with a gestational age of less than 37 weeks and/or of birth weight of less than 2,500 g contributed for 56.2% and 68.7% of the total perinatal losses respectively. PMR was three fold higher among twins compared with singleton births. Identifiable causes of perinatal deaths observed were: asphyxia (31%), congenital anomalies (18.7%), sepsis (18.7%) and low birth weight (25%). It would appear that preventable factors are operative in over two third of the cases of perinatal loss and better maternal health, obstetric and neonatal care can improve the perinatal outcome in majority of the cases.

Fetal Death↗
PubMed1991

Bacterial meningitis: T cell activation and immunoregulatory CD4+ T cell subset alteration.

Meningitis is the most important cause of acquired postnatal deafness and neurologic disorders in children. To determine if cell-mediated immunity is casually related to the pathogenesis of bacterial meningitis, T cell subsets were quantitated from blood of the 29 children with clinical and bacteriologic diagnosis of Haemophilus influenzae, Streptococcus pneumoniae, and Neisseria meningitidis bacterial meningitis. The CD4+ T cells increased and CD8+ T cells decreased in patients with meningitis as compared to patient control subjects (bacterial infections without meningitis) and normal healthy control subjects. An elevated percentage of CD25+ (interleukin-2 receptors) and HLA-DR+ (immune-response gene-associated antigen) T cells were detected from all patients with meningitis. All 29 patients with meningitis had highly elevated CD4+ CD45R+ (suppressor-inducer) cells and reciprocally depressed CD4+ CDw29+ (helper-inducer) cells compared with healthy age-matched normal and patient control subjects. These findings indicate characteristic immunologic T cell abnormalities from meningitis. The abnormal increase in the CD4+ CD45R+ suppressor-inducer or "virgin" cells and expression of activation antigens on T cells may be of help in future understanding of abnormal immune reactions from bacterial meningitis. However, deficiency of the CD4+ CDw29+ helper-inducer or "memory" cells may contribute to the impaired helper function for B cell-induced protective antibody synthesis to bacterial capsular polysaccharides found in this disease.

Antigens, CD↗
PubMed1989

Perinatal risk factors in birth asphyxia: relationship of obstetric and neonatal complications to neonatal mortality in 16,365 consecutive live births.

Over a period of one year, 16,365 consecutively live born neonates were prospectively studied for evidence of birth asphyxia using the requirement of greater than one minute of positive pressure ventilation for identifying infants suffering from birth asphyxia. Asphyxia occurred in 2.8% of all neonates. Multivariate analysis of high risk factors associated with increased risk of asphyxia showed that low birth weight was the most significant predictor of asphyxia: asphyxia occurred in 68% of infants of less than 1,000 g birth weight and decreased to 1.2% in infants of 3-4 kg birth weight. Perinatal risk factors associated with a higher incidence of asphyxia include: postmaturity, birth weight (less than or equal to 2.5 kg) and with the presence of maternal and/or obstetric complications. The impact of asphyxia on neonatal mortality was most pronounced in more mature infants and the mortality was increased 3 fold in infants of less than 34 week gestation and greater than 27 fold for infants greater than 38 week gestation. Of the asphyxiated neonates, intrauterine growth retardation, fetal macrosomia, hypothermia, hyaline membrane disease, seizures, hypoglycemia and hyponatremia were significantly associated with an increased risk of death.

Adolescent↗
PubMed1988

Anterior fontanelle size in Arab children: standards for appropriately grown full term neonates.

The anterior fontanelle (AF) size of 100 male and 100 female normal neonates, born by spontaneous vertex delivery following a normal pregnancy, was determined on the 3rd day of life, using standard methods. The mean AF size for boys was 2.92 (0.51) (range 1.04-4.4) cm and for girls 2.51 (0.74) (range 1.0-4.1) cm. The difference between the sexes is significant (P less than 0.001). There was no significant difference in the head circumference between the sexes. The study establishes normal values for anterior fontanelle size for appropriately grown, full term Arab male and female infants.

Cephalometry↗
PubMed1988

Mechanical ventilation in newborn infants.

A 20-month experience of mechanical ventilation (MV) in the newborn infants (birth weight greater than or equal to 1500 g) from a developing country is described. A total of 41 neonates (4.1% of total admissions to the Neonatal Intensive Care Unit) were treated with MV. The mode of MV was intermittent positive pressure ventilation and continuous positive airway pressure via nasotracheal intubation. The mean birth weight and gestational age were 2544 g and 36.2 weeks, respectively. The mean age at the start of MV was 141 h and the mean duration was 54 h. The indications for MV were respiratory distress syndrome (18), aspiration pneumonia (8), non-aspiration pneumonia (6), apnoea (8) and tetanus neonatorum (1). The complications encountered during MV were sepsis (26.8%), pulmonary haemorrhage (21.9%), congestive heart failure (17.1%), pneumothorax (14.6%) and intraventricular haemorrhage (7.3%). Post-extubation atelectasis was observed in 29.6% of cases. The overall survival rate was 43.9%. The risk factors for a poor outcome were birth weight less than 2000 g, prematurity and late referrals to the Neonatal Intensive Care Unit.

Apnea↗
PubMed1986

Congenital choanal atresia in North African infants.

Eleven cases of congenital choanal atresia seen over a period of 2 years are described. Its incidence in the community was 1 in 3100 births. Twenty-seven per cent of cases were missed at birth, suggesting an even higher incidence. The anomaly was significantly commoner in infants of younger mothers with less than four children (P less than or equal to 0.05). Maternal polyhydramnios was present in three cases (P less than or equal to 0.0001). The sex incidence was equivocal and three infants were of low birthweight. The atresia was bilateral in the majority of the cases, and associated congenital anomalies were present in five of the 11 infants. Five underwent surgery with no complications.

Adult↗