Letters to the editor

Although we do not have a regular Letter to the Editor column, we believe the following exchange of letters has sufficient scientific merit to warrant reproduction here. Dr. T.E. Keats and Dr. Dennis J. Stoker, Editors.     

Helicobacter pylori in dental plaque of Pakistanis

Helicobacter pylori is now generally accepted to play a key role in acid related and neoplastic pathology of gastroduodenal diseases. Recent reports have concluded that dental plaque is not an important reservoir for Helicobacter pylori, however, these studies did not consider the ethnic background of their subjects nor the amounts of dental plaque present. The aim of this study was to explore the association of Helicobacter pylori dental plaque colonisation in 125 males and 53 females (group I) attending a dental clinic in Pakistan. A simultaneous sample of 30 healthy volunteers with good orodental hygiene consisting of 17 males and 13 females was included as a control group (group II). Six dental plaque specimens were obtained from each subject with a sickle scaler; two were inoculated into CLO test gel and the remaining four were used to prepare cytology slides stained with Giemsa's stain. CLO test was positive in all specimens from group I, while cytology for Helicobacter pylori was positive in 173 cases in this group. One hundred and forty two cases had heavy plaque deposits and all of them were positive on cytology. In group II CLO test was positive in 20 and dental plaque cytology was positive in 7 cases. In conclusion, it is important that future studies into the prevalence of Helicobacter pylori in the oral cavity should take into account the levels of oral cleanliness and the ethnic background of the subjects.     

Low birth weight: an outcome of poor socio-obstetric interaction

Factors contributing to low birth weight (LBW) include poverty, ignorance, and inability to use health care services. Early marriage and low family income lead to poor maternal nutrition reserves, which lead to reduced fetal nutrition. Poor maternal nutrition is also the result of ignorance, short birth intervals, multi-parity, and lack of prenatal care. Both heavy manual labor and smoking contribute to placental ischemia, which, along with reduced fetal nutrition, leads to intrauterine growth retardation (IUGR). In developing countries, IUGR accounts for over 66% of all LBW neonates. About 7 million Indian babies annually are LBW. This study examined the incidence of LBW among 178 mothers delivering single births at the maternity hospital associated with the Department of Community Medicine of SKIMS, Srinagar, Kashmir, India, during 1989-90. 26.40% (47) of the 178 births were LBW (2500 g). Among 71 first-borns, marriage age was found to be statistically significantly associated with LBW. 31.82% of mothers younger than 20 years had LBW babies, compared to only 6.12% of mothers older than 20 years. The impact ratio, which measured excess LBW, was 4.20. Birth interval was statistically significantly associated with LBW outcome. 55.81% of women with a birth interval of less than 18 months had LBW babies, compared to 20.31% of mothers with longer birth intervals. The impact ratio was 1.75. Gravidity was also statistically associated with LBW babies. 34.58% of multigravida mothers had LBW babies, compared to 14.08% of primigravidae. The impact ratio was 1.46. Presence of prenatal care was statistically associated; the impact ratio was 1.42. 31.30% of illiterate women had LBW babies, compared to only 17.46% among literate women, which indicated significant associations with LBW. Other significant factors were manual labor, maternal smoking, and monthly family income. Reduction of LBW by 10-30% nationally by the year 2000 will be difficult and best accomplished by a high risk approach supplemented by health and nutrition education.     

Pulmonary mechanics and outcome of neonates on ECMO.

Deciding when to wean neonates from extracorporal membrane oxygenation (ECMO) can be difficult. The usefulness of simple measurements of pulmonary mechanics e.g., dynamic compliance (Cdyn) has been questioned. We investigated the pulmonary mechanics of eight neonates using the interrupter technique, which allows the partitioning of pulmonary mechanics into compartments representing the conducting airways and more peripheral phenomena (viscoelastic properties and "pendelluft"). Three neonates required ECMO for a congenital diaphragmatic hernia (CDH), two for hyaline membrane disease (HMO), two for meconium aspiration syndrome (MAS), and one for pneumonia. All neonates with MAS, HMD, and pneumonia were successfully weaned from ECMO when their Cdyn was 0.3 mL/cmH2O/kg or greater [mean 0.34 +/- 0.06 (SEM)]. All three neonates with CDH died and their highest Cdyn was 0.21, 0.19, and 0.09 mL/cmH2O/kg respectively (mean, 0.16 +/- 0.037). The airway resistance (Raw) and the slower component of pressure change after interruption (delta Pdiff), a measure of the more peripheral phenomena of the lung, were not significantly different in those neonates who survived and those who did not. The values for delta Pdiff in all patients were higher than those in healthy neonates. However, the Raw was not different. This suggests that the major disturbance in pulmonary mechanics was distal to the conducting airways. Those neonates who were successfully weaned from ECMO had a significantly higher Cdyn 24-48 hours prior to decannulation. Considering the lung as a two-compartment model offers no advantages when compared to the one-compartment model for the prediction of the outcome of a neonate on ECMO.