TEN YEARS' EXPERIENCE IN LOW VISION PRACTICE

The Low Vision Clinic at the Palmerston North Hospital has now been oerating for 70 years. Over the course of these ten years a number of factors have emerged which can be as readily applied to general ophthalmological practice as to low vision practice. The philosophy of low vision care is one of which all ophthalmologists should be aware and includes factors to be taken into account when dealing with children, people in the workplace, and everyday factors involved in daily living activities, all of which are equally relevant in routine ophthalmological practice. This paper endeavours to share some thoughts on these factors and also discusses means by which the visually handicapped can be helped in areas where specialist low vision services are not readily available.     

A population-based assessment of the disease burden of consolidated pneumonia in hospitalized children under five years of age.

BACKGROUND: Population-based studies on childhood community-acquired pneumonia are scarce in Latin America. Pneumococcal epidemiology is poorly defined, hence the World Health Organization recommended standardized chest radiograph interpretation to improve the approach to bacterial pneumonia. Therefore, our study aimed to estimate the burden of pneumonia in hospitalized children. METHODS: A three-year surveillance study was carried out in four hospitals covering a population of 229,128 inhabitants of whom 10.2% were under five years of age. Clinical records and digitization of their chest radiographs were obtained. A pediatrician and a pediatric radiologist blinded to the clinical diagnosis interpreted the digital images. RESULTS: Of 2034 patients, 826 (40.6%) had consolidated pneumonia, 941 (46.3%) had non-consolidated pneumonia, and 267 (13.1%) had no pneumonia. Children under two years of age predominated (66.9%). The average annual incidence rate for consolidated pneumonia over the three-year study period was 1175/10(5). Eighteen invasive Streptococcus pneumoniae were isolated from patients with consolidated pneumonia and two from those with non-consolidated pneumonia. Respiratory syncytial virus was evenly distributed between both X-ray groups. CONCLUSIONS: Patients younger than two years of age predominated, being the main targets for anti-pneumococcal conjugated vaccines. Incidence rates provided evidence of the burden of consolidated pneumonia for childhood, estimating the potential benefits of vaccination.     

The relevance of therapeutic drug monitoring in plasma and erythrocytes in anti-cancer drug treatment.

Therapeutic drug monitoring generally focuses on the plasma compartment only. Differentiation between the total plasma concentration and the free fraction (plasma water) has been described for a number of limited drugs. Besides the plasma compartment, blood has also a cellular fraction which has by far the largest theoretical surface and volume for drug transport. It is with anti-cancer drugs that major progress has been made in the study of partition between the largest cellular blood compartment, i.e., erythrocytes, and the plasma compartment. The aim of the present review is to detail the progress made in predicting what a drug does in the body, i.e., pharmacodynamics including toxicity and plasma and/or red blood cell concentration monitoring. Furthermore, techniques generally used in anti-cancer drug monitoring are highlighted. Data for complex Bayesian statistical approaches and population kinetics studies are beyond the scope of this review, since this is generally limited to the plasma compartment only.     

Estado actual del valor pronóstico de los marcadores moleculares en pacientes con cáncer colorrectal y la predicción de respuesta al tratamiento adyuvante

Colorectal cancer is one of the best studied of all malignant diseases interms of genetics and/or molecular prognostic factors. These factors, and relationships with prognosis, may have important implications especially in the design of surgical and adjuvant chemo-radiotherapy options. However, the true prognostic significance of all known factors has yet to be realised. We have reviewed the literature with specific focus on the role of molecular markers involved in prognosis and the prediction of response to adjuvant treatment.     

The value of MCA, CA 15-3, CEA and CA-125 for discrimination between metastatic breast cancer and adenocarcinoma of other primary sites

MCA, CA 15-3, CEA and CA 125 were determined in the serum of 49 patients with metastatic breast cancer and 38 patients with metastatic adenocarcinoma of other primary sites. By using the 99th percentile of the normal value distribution as the cut-off point, the positive predictive value (PV+) was found to be 85% (95% CI 76-94) for MCA, and 71% (95% CI 61-81) for CA 15-3. When receiver-operating-characteristic (ROC) curves were constructed, the PV+ for CA 15-3 was increased to 82% (95% CI 72-92), using 60 U ml-1 as the cut-off point. With the exception of two patients who had a slightly elevated MCA, MCA and CA 15-3 identified the same patients with breast cancer. By combining a positive MCA or CA 15-3 with a negative CEA and CA 125, further improvement of the PV+ could be achieved; 100% (95% CI 91-100). We conclude that MCA and CA 15-3 may play a useful role in discrimination between patients with metastatic breast cancer and those with adenocarcinoma of other primary sites.     

Comparison of trichloroethylene and enflurane as adjuncts to nitrous oxide and relaxant anaesthesia

Forty women who underwent gynaecological surgery were randomly allocated to receive trichloroethylene, enflurane, or enflurane plus fentanyl as adjuncts to nitrous oxide/relaxant anaesthesia with controlled ventilation. No serious cardiac dysrhythmias were seen in any group. Each patient was observed postoperatively for 4 hours by a nurse blind to the technique used, and questioned at 24 hours by a similarly blinded anaesthetist. Recovery after trichloroethylene was not significantly prolonged although postoperative analgesia by visual analogue was better, opiate analgesia was required less frequently and there was less nausea and vomiting than in either of the enflurane groups. We argue for the continued use of trichloroethylene by this technique, because it costs one hundred times less than enflurane and because of the potential morbidity of the postoperative opiate dosage required after enflurane.     

The ventral rib cage muscles in the dog: contractile properties and operating lengths

To have some insight into the mechanical interplay between the parasternal intercostal and triangularis sterni muscles during breathing, we have examined the isometric contractile properties of these two muscles in the dog. Using piezoelectric crystals, we have also measured the respiratory changes in muscle length in eight spontaneously breathing animals in the supine posture, and we have compared the in situ relaxation length (Lr) of these two muscles to their respective in vitro optimal force-producing length (Lo). The triangularis sterni and parasternal intercostals had similar isometric twitch, force-frequency, and length-tension characteristics. These two muscles, therefore, are intrinsically similar. In supine dogs, however, they operate on quite distinct segments of their length-tension curve. Whereas Lr for the parasternals corresponded to 117% Lo, Lr for the triangularis sterni was only 75% Lo. This suggests that the triangularis sterni in supine dogs operates on a poorly advantageous portion of its length-tension curve. However, shortening of the parasternals during inspiration causes considerable passive distension of the muscle. As a result, the triangularis sterni is much closer to its optimal length when it starts contracting in early expiration.