Administration of Vitamin K to newborns: implications and recommendations.

The review by Drs. Brousson and Klein (see pages 307 to 315 of this issue) identifies controversies surrounding the administration of vitamin K to babies shortly after birth. Controlled studies comparing the effect of oral and intramuscular administration are unlikely to be conducted because of the large number of subjects needed. The evidence presented in the review should dispel concerns that intramuscular administration may be associated with childhood cancer. Oral administration of a single dose of vitamin K soon after is associated with significant biochemical vitamin K deficiency by 1 month of age, but the relation of biochemical abnormality to clinical manifestations of late hemorrhagic disease of the newborn is less clear. Epidemiologic studies indicate a small, but significant, increase in the incidence rate of hemorrhagic disease after oral administration of vitamin K (1.0 to 6.4 incidents per 1000 000 infants), compared with the incidence rate after intramuscular administration (0.25 incidents per 100 000 infants). Although repeated oral doses of vitamin K may be and effective alternative regimen, there is no approved oral vitamin K formulation, there are concerns about patient compliance, and there has been limited investigation of such regimen. Therefore, intramuscular administration of a single dose of 1.0 mg of vitamin K shortly after birth is recommended.     

Pressure recovery distal to a stenosis: potential cause of gradient "overestimation" by Doppler echocardiography

Doppler ultrasound is currently being widely applied to measure intracardiac pressure gradients noninvasively. In comparative invasive studies, it is generally assumed that pressure is effectively uniform distal to the stenosis. As the poststenotic jet expands, however, its velocity decreases, and pressure is recovered to the extent permitted by turbulence, so that the measured gradient will be lower if the distal catheter is positioned downstream from the vena contracta. This can lead to apparent Doppler "overestimation" of the pressure gradient because of this phenomenon of pressure recovery. This study demonstrates that pressure recovery can be important in a variety of clinical settings studied by in vitro models. Although most prominent in streamlined tunnels modeled after the obstruction in patients with hypertrophic cardiomyopathy, these effects are important even for central stenoses at physiologic flow rates. Because precise catheter position is not always known or controlled, these findings suggest an important advantage for Doppler gradient estimation, because it provides the maximal gradient at the vena contracta, which determines the load on the proximal chamber.     

Morphometric evaluation of hepatocellular proliferative lesions in the rat liver

Classification of rat hepatocellular proliferative lesions can vary between pathologists as the many qualitative histologic criteria have not been satisfactorily evaluated and ranked for prognostic value. Computer-assisted morphometry offers an objective method to evaluate certain cellular features. The Solt-Farber resistant hepatocyte model was used in this study to produce populations of rats with a full range of hepatocellular proliferative lesions. Cellular features within the lesions were then measured morphometrically and the data were analyzed by animal age and by subjective lesion diagnosis. The nuclear/cytoplasmic ratio followed by the cell area and nuclear area were found to be the most important parameters for separating microscopic foci and islands of cellular alteration, an early hyperplastic lesion, from other hepatocellular proliferative lesions. The coefficient of variation, as a relative measure of heterogeneity, increased in a linear manner for cell, nuclear and nucleolar areas as the animals aged and was significantly higher for cell and nuclear area in hepatocellular carcinoma compared to other hepatocellular proliferative lesions. Hepatocyte nodules (representing primarily late hyperplastic lesions) and persistent hepatocyte nodules (lesions with similarities to hepatocellular adenoma) could not be satisfactorily separated within the limits of this study. As these borderline lesions show a continuum of cytologic change, other features, such as architectural change, are necessary to satisfactorily classify them on a subjective basis. An alternative approach is to use discriminant functions derived from morphometric studies.     

Non-cultural detection of Neisseria gonorrhoeae in cervical and vaginal washings

Genetic transformation, an indirect sandwich enzyme-linked immunosorbent assay (ELISA) and the Limulus amoebocyte assay were used to indicate the presence of products of Neisseria gonorrhoeae in vaginal and uterine cervical aspirates from 37 women attending a Department of Genito-Urinary Medicine. In parallel with these tests, qualitative and quantitative assessments of the microbial content of aspirates were made. There was wide variation in the numbers of gonococci cultured. The mean viable count for cervical aspirates was 1 x 10(6) cfu/ml and the range was (5 x 10(3))-(8 x 10(6)) cfu/ml; the mean count for vaginal aspirates was 8.4 x 10(4) cfu/ml and the range (1 x 10(2))-(1 x 10(6)) cfu/ml. Viable counts of organisms other than gonococci in vaginal aspirates were two to tenfold greater than the corresponding counts for cervical aspirates. Of 20 patients with gonorrhoea confirmed by conventional diagnostic cultures, aspirates from 15 (75%) gave a positive transformation result, and 12 (60%) a positive ELISA result; 16 (84.2%) out of 19 of these aspirates tested by the Limulus lysate assay were positive at a dilution of 1 in 100.     

Screening for coeliac disease as a possible maternal risk factor for neural tube defect

Coeliac disease is an important cause of malabsorption, particularly of folic acid, in adults. We investigated the possibility that it might be a maternal risk factor for neural tube defect (NTD)-associated pregnancy by screening affected mothers using serum endomysial antibody (EmA) which has high sensitivity and specificity for coeliac disease. One (1.6%) of 60 patients was EmA positive and had a diagnosis of coeliac disease confirmed by the finding of villous atrophy on jejunal biopsy. In conclusion, the majority of NTD-associated pregnancies are not associated with maternal coeliac disease and our study is additional evidence that abnormalities of folic acid metabolism rather than absorption are the most important risk factors for NTD. Further studies are needed to determine whether the coeliac disease prevalence among women with NTD-affected pregnancy is higher than that of the general population.     

Palmitate turnover and its response to glucose infusion in weight-losing cancer patients

Palmitate turnover in weight-stable control subjects (n = 4) and weight-losing patients with progressive malignant disease (n = 4) has been determined. Measurements were made after an overnight fast and during glucose infusion (3.5 mg/kg/min). Turnover rates were calculated from plateau isotopic enrichment of palmitate in plasma during a continuous infusion of 1-13C palmitate. Palmitate turnover was higher in the cancer group before (180%) and during glucose loading (170%) compared with the control group. Palmitate turnover was reduced during glucose administration by approximately 34% in both groups. Plasma concentration of insulin was decreased and of cortisol was increased in the cancer group compared with the control group before and during glucose infusion. We conclude that cancer patients with weight loss have increased rates of fatty acid turnover indicative of enhanced mobilisation of body fat stores. Altered plasma concentrations of insulin and cortisol may mediate this effect. Nonetheless, even at more advanced stages of cachexia cancer patients have normal control mechanisms for inhibiting fatty acid turnover following administration of carbohydrate.     

Disruption of temporal discrimination by drugs of abuse: I. Unmasking of a color bias

Pigeons were trained to discriminate the length of a delay period (3s vs. 10s). Under control conditions, pigeons were able to discriminate between the two delay period lengths with a high degree of accuracy (>90%). When delays of 1, 3, 5, 7, 9 and 11s were randomly presented, the percentage of responses appropriate to the 10s delay increased as a function of increasing delay length. Dose-response curves determined for a series of drugs of abuse showed that pentobarbital, diazepam and phencyclidine displayed the greatest efficacy in disrupting the discrimination. The decrease in accuracy was a function of both a decrease in the ability of the pigeon to discriminate the passage of time, and the expression of a drug-induced red color bias. When the stimulus colors were changed, these drugs still decreased accuracy of the discrimination without any evidence of a color bias. Morphine disrupted the discrimination at doses which produced marked response suppression; there was no evidence of a drug-induced color bias. Delta(9)-THC failed to produce any significant effect on the discrimination. d-amphetamine and cocaine initially had no effect; however, upon subsequent determinations and when the stimulus colors were changed during the last part of the experiment, they did disrupt discrimination performance. These results show that drugs of abuse have differential effects on temporal discrimination, with some drugs affecting temporal discrimination at doses that do not suppress responding, some affecting the discrimination at doses that decrease response rates, and others that do not appear to affect temporal discrimination. Only sedative/hypnotic drugs disrupted temporal discrimination in part by producing a red-color bias.     

The emergency medicine training needs of rural general practitioners

This study aimed to identify the emergency medicine training needs of rural general practitioners (GPs) in the catchment area of the Hunter Rural Division of General Practice. The GPs were surveyed using a questionnaire in which they were asked about their confidence levels in a number of specific emergency medicine skills, and about the areas of emergency medicine that they saw as priorities for upskilling. More than a third of GPs who were responsible for on-call work at the hospital indicated that they had low levels of confidence in a number of their emergency medicine skills, in particular skills relating to paediatric emergencies, cardiovascular emergencies, and respiratory emergencies. These emergency medicine domains were also seen as high priorities for upskilling by the majority of the respondents. The study shows that rural doctors need the opportunity to access emergency medicine training that provides upskilling not only in the management of clinical problems, but also in practical procedures.     

Developments in imaging. An historical review

Following the discovery of X-rays by Roentgen in 1895, it was 70 years later that the specialty of imaging really took off, with ultrasound, CT, Nuclear medicine, and MRI now an integral part of all large departments. The recent progress has been accelerated by advances in computer technology which aided the development of imaging techniques that do not use ionising radiation. Some imaging techniques are replacing other more hazardous diagnostic procedures, (e.g. MRCP v ERCP, and MRA v catheter angiography) while some are able to provide almost perfect anatomical detail e.g. brain MRI. Techniques using radioisotopes provide more functional information which can be used to complement the morphological studies. We have witnessed the birth and maturation of Interventional Radiology. This is a highly skilled subspecialty enabling some surgical procedures to be replaced by minimally invasive methods using image guidance. These range from simple drainage procedures and guided biopsies to complex aortic bifurcation stent graft insertions. The potential for digital storage of all images is already established and the filmless radiology department in the more developed countries could be the norm by 2020.