Dietary habits and dental health over the first 18 months of life

OBJECTIVES

The main objective of this study was to describe the dental health of infants and toddlers with special reference to their dietary habits and oral hygiene behaviour over the first 18 months of life.

METHODS

The longitudinal dietary data were obtained at 6, 12 and 18 months of age by using a 3-day weighed diet diary. Dental examinations were carried out at 12, and again at 18 months of age. The information on demographic factors and oral hygiene behaviours over the first 18 months of life was gathered by using a structured questionnaire at 12 and 18 months.

RESULTS

163 children were studied. Visible dental plaque was present in 18% and 25% of children at 12 and 18 months of age, respectively. No child had dental caries at either 12 or 18 months of age. There was a statistically significant correlation between visible plaque measured as plaque index at 12 months and the mean daily eating/drinking episodes at 6 months (r=0.25, P=0.001) and 12 months (r=0.15, P=0.05). The correlations between plaque index at 18 months and the mean eating/drinking episodes at both 12 months (r=0.2, P=0.04) and 18 months (r=0.2, P=0.02) were low but statistically significant. Nevertheless, there was no significant correlation between accumulation of plaque at either 12 or 18 months and the mean daily frequency consumption of food and drink containing non-milk extrinsic sugars (NMES) at any age. Children who brushed their teeth themselves were more likely to have visible plaque compared with children whose teeth were cleaned by their parents. The partial correlation showed that positive relation between mean daily eating/drinking episodes and plaque was not influenced by tooth brushing.

Efficacy of two alternate vaccines based on Plasmodium falciparum merozoite surface protein 1 in an Aotus challenge trial

In an attempt to produce a more defined, clinical-grade version of a vaccine based on Plasmodium falciparum merozoite surface protein 1 (MSP1), we evaluated the efficacy of two recombinant forms of MSP1 in an Aotus nancymai challenge model system. One recombinant vaccine, bvMSP1(42), based on the 42-kDa C-terminal portion of MSP1, was expressed as a secreted protein in baculovirus-infected insect cells. A highly pure baculovirus product could be reproducibly expressed and purified at yields in excess of 8 mg of pure protein per liter of culture. This protein, when tested for efficacy in the Aotus challenge model, gave significant protection, with only one of seven monkeys requiring treatment for uncontrolled parasitemia after challenge with P. falciparum. The second recombinant protein, P30P2MSP1(19), has been used in previous studies and is based on the smaller, C-terminal 19-kDa portion of MSP1 expressed in Saccharomyces cerevisiae. Substantial changes were made in its production process to optimize expression. The optimum form of this vaccine antigen (as judged by in vitro and in vivo indicators) was then evaluated, along with bvMSP1(42), for efficacy in the A. nancymai system. The new formulation of P30P3MSP1(19) performed significantly worse than bvMSP1(42) and appeared to be less efficacious than we have found in the past, with four of seven monkeys in the vaccinated group requiring treatment for uncontrolled parasitemia. With both antigens, protection was seen only when high antibody levels were obtained by formulation of the vaccines in Freund's adjuvant. Vaccine formulation in an alternate adjuvant, MF59, resulted in significantly lower antibody titers and no protection.

An epidemic without illness. Using dna markers to model infection

PURPOSE: Combining molecular biology with infection control interventions can increase compliance and allow objective measurement of effectiveness. We developed a group of PCR detectable non-infectious DNA markers that can be used to model infection and provide immediate feedback on hygiene practices in institutional settings. In previous studies, we illustrated that the markers were spread in the environment in the same manner as infectious particles.METHODS: We are conducting a prospective study in 10 child care centers in order to 1) confirm that the DNA markers are valid surrogates for bacteria and viruses; 2) identify specific foci of contamination and modes of transmission; 3) illustrate the effectiveness of infection control programs utilizing the DNA markers. Centers are randomized to receive an interactive educational infection control intervention or a standard immunization intervention. The DNA markers are introduced into the center and the rate of dispersion of the DNA markers is compared with directly observed changes in hygiene behavior among the staff.RESULTS: Initial results indicate that the markers can be removed mechanically by hand washing and that common over-the-counter cleaners are effective in inactivating the markers. Toys, countertops and doorknobs appear to be more important as infectious reservoirs than brief casual contact. Data from the prospective study will be available prior to September, 2000.CONCLUSIONS: This novel approach utilizing an objective measurement will be used to identify the interaction between behavior and environmental reservoirs of infection and drive future strategies for infection control.

Experimental study of the magnetic stereotaxis system for catheter manipulation within the brain

OBJECT

The magnetic stereotaxis system (MSS) is a device designed to direct catheter tips through magnetic forces. In this study the authors tested the safety and performance of the MSS in directing catheters through a nonlinear path to obtain biopsy specimens in pig brains.

METHODS

Sixteen pigs underwent biopsy of the frontal brain region with the aid of an MSS (11 pigs) or a standard stereotactic biopsy tool (five pigs). Surgical preparation consisted of placement of six fiducial markers in the skull and the creation of a burr hole for attachment of a cranial bolt and passage of the biopsy catheter. The pigs underwent magnetic resonance (MR) imaging of the head to define a biopsy target and to plan a nonlinear path. Guided by the MSS, which used nearly real-time fluoroscopic imaging fused to the preoperative MR image, the authors advanced a catheter to the biopsy target. A biopsy tool was passed through the catheter and a tissue sample was obtained. The animals were observed for 3 to 5 days postoperatively, when they were assessed for neurological abnormalities or other signs of morbidity. Actual catheter placement was within 1.5 mm of the planned path to the biopsy site, using a minimum path radius of 30 mm. The registration error associated with the use of the MSS x-ray fluoroscopy and MR imaging averaged 1.7 mm. Tissue disruption caused by the MSS was similar to that of standard stereotactic procedures.

CONCLUSIONS

The MSS affords accurate and safe guidance of brain catheters in animals. The application tested here, brain biopsy, is one of a number of potential catheter-guided procedures.

Measuring cell proliferation in the rectal mucosa. comparing bromodeoxyuridine (BrdU) and proliferating cell nuclear antigen (PCNA) assays

Cell proliferation in the human colorectum can be measured using bromodeoxyuridine (BrdU) or proliferating cell nuclear antigen (PCNA) assays. Using data from the National Cancer Institute's Polyp Prevention Trial, these two assays are compared using correlation coefficients and variance components analysis. Adjusting for fixed as well as for the random effects of between-biopsy and scoring variation, the estimated correlation is 0.46 for the log labeling index and 0.45 for log proliferative height. This is an estimate of the highest correlation that can be achieved by taking multiple biopsies scored by multiple scorers. For single biopsies, the estimated correlation is 0.16 and 0.10, respectively. There are significant differences between the variance components for the two assays. For example, for log labeling index, PCNA has a lower variation between biopsies than BrdU, but higher variation between scorings. When used in a clinical or epidemiological setting, it is important to take multiple biopsies at multiple time points.

Consistency of teaching in parallel surgical firms: an audit of student experience at one medical school

BACKGROUND

Traditional clinical clerkships have been based on the apprenticeship model of learning, with opportunistic teaching by doctors on presenting patients. Students at King's College School of Medicine, London had expressed concern that they were receiving inequitable experiences in different clerkships. This had become more apparent since the introduction of a school-wide end-of-year skills assessment. We decided to assess the consistency of delivery of the surgical syllabus.

METHOD

A multistage questionnaire survey was undertaken with third-year (first clinical year) undergraduate medical students on surgical clerkships. The questionnaire required students to record topics about which they had been taught, and practical skills on which they had been supervised, from the surgical syllabus pertaining at the time.

RESULTS

194 (46.4%) questionnaires were returned. A low level of consistency was reported in the teaching of theoretical topics and practical skills across surgical clerkships in eight different locations. There were substantial differences, both in overall coverage of the syllabus and in the priority given to different topics. There were no overall differences between teaching hospital- and district general hospital-based clerkships.

DISCUSSION

Students in so called 'parallel' clerkships did not receive comparable teaching. The traditional opportunistic nature of clinical teaching led, in effect, to individual curricula within each clerkship. The General Medical Council has called for a core curriculum to be delivered across different clinical sites within each medical school. To achieve this, medical schools may need to introduce guidelines to direct teaching in the same way that clinical protocols have been developed to achieve greater standardization in clinical practice.

Regions of the human brain affected during a liquid-meal taste perception in the fasting state: a positron emission tomography study

BACKGROUND

The sensation of taste provides reinforcement for eating and is of possible relevance to the clinical problem of obesity.

OBJECTIVE

Positron emission tomography (PET) was used to explore regions of the brain that were preferentially affected during the taste perception of a liquid meal by 11 right-handed, lean men in the fasting state.

DESIGN

After subjects had fasted for 36 h, 2 measurements of regional cerebral blood flow (rCBF) obtained immediately after subjects retained and swallowed 2 mL of a flavored liquid meal (the taste condition) were compared with 2 measurements of rCBF obtained immediately after subjects retained and swallowed 2 mL of water (the baseline condition).

RESULTS

Compared with the baseline condition, taste was associated with increased rCBF (P < 0.005) in the left dorsolateral prefrontal cortex and superior temporal gyrus; the right ventrolateral prefrontal cortex, supramarginal gyrus, and anterior thalamus; and bilaterally in the hippocampal formation, posterior cingulate, midbrain, occipital cortex, and cerebellum. Taste was also associated with decreased rCBF (P < 0.005) in the right dorsolateral prefrontal cortex, superior temporal gyrus, and supplementary motor area, and bilaterally in the medial prefrontal cortex and inferior parietal lobule.

CONCLUSIONS

This exploratory study provides additional evidence that the temporal cortex, thalamus, cingulate cortex, caudate, and hippocampal formation are preferentially affected by taste stimulation. The asymmetric pattern of activity in the dorsolateral prefrontal cortex and superior temporal gyrus may contribute to the taste perception of a liquid meal perceived as pleasant. Additional studies are required to determine how these regions are affected in patients with obesity or anorexia.

Recent medical evidence for torture and human rights abuse in Sierra Leone: a report for the Medical Foundation for the Care of Victims of Torture

A study was carried out using the case notes of all Sierra Leoneans referred to the Medical Foundation for the Care of Victims of Torture between 1996 and 1998 for medical reports. Data were abstracted on the type and extent of torture reported, and the cases were followed up to the present day to ascertain how long the United Kingdom asylum and immigration process had taken to process their claims. In the sample of 36 cases there were 68 reported incidents of torture or human rights abuse. Sixty-nine per cent (18/26) of the women in the sample had been raped at least once, and 72% (26/36) of the sample had been beaten at least once. The average time for the minimum due process of the asylum claim to be processed was 44 months (3.7 years). On 31 January 1999, 61% of the sample (22 people) were still involved in the asylum process. Waiting times must be reduced and safeguards imposed so that those who have suffered torture can be rapidly identified and referred for medical treatment, care and documentation.

Neuroanatomical correlates of hunger and satiation in humans using positron emission tomography

The central role of the hypothalamus in the origination and/or processing of feeding-related stimuli may be modulated by the activity of other functional areas of the brain including the insular cortex (involved in enteroceptive monitoring) and the prefrontal cortex (involved in the inhibition of inappropriate response tendencies). Regional cerebral blood flow (rCBF), a marker of neuronal activity, was measured in 11 healthy, normal-weight men by using positron emission tomography in a state of hunger (after 36-h fast) and a state of satiation (after a liquid meal). Hunger was associated with significantly increased rCBF in the vicinity of the hypothalamus and insular cortex and in additional paralimbic and limbic areas (orbitofrontal cortex, anterior cingulate cortex, and parahippocampal and hippocampal formation), thalamus, caudate, precuneus, putamen, and cerebellum. Satiation was associated with increased rCBF in the vicinity of the ventromedial prefrontal cortex, dorsolateral prefrontal cortex, and inferior parietal lobule. Changes in plasma insulin concentrations in response to the meal were negatively correlated with changes in rCBF in the insular and orbitofrontal cortex. Changes in plasma free fatty acid concentrations in response to the meal were negatively correlated with changes in rCBF in the anterior cingulate and positively correlated with changes in rCBF in the dorsolateral prefrontal cortex. In conclusion, these findings raise the possibility that several regions of the brain participate in the regulation of hunger and satiation and that insulin and free fatty acids may be metabolic modulators of postprandial brain neuronal events. Although exploratory, the present study provides a foundation for investigating the human brain regions and cognitive operations that respond to nutritional stimuli.

Dietary and lifestyle factors affecting plasma vitamin D levels in Asian children living in England

OBJECTIVE

To determine the vitamin D status of a sample of young Asian children living in England by measurement of plasma 25-hydroxycholecalciferol levels; to relate biochemical measurements with parameters of diet, lifestyle and iron status in this population.

DESIGN

The 'Infant Feeding in Asian Families' survey covered infants born to mothers of Bangladeshi, Indian or Pakistani origin, plus a sample of children born to White mothers in 41 local authority areas. The current study describes vitamin D values in a sub sample of Asian children from that survey.

SETTING

Forty-one local authority areas which covered 95% of the Asian population at the time of the 1991 Census and include areas with the highest and lowest density of Asians.

SUBJECTS

Seventy-one percent (2382) of mothers who were originally eligible were interviewed on four occasions up to the time their infant was 15 months. One thousand, seven hundred and thirty-eight of these children were followed up for this current study. Of these 618 had a blood sample analysed for vitamin D.

OUTCOME MEASURES

Previous day's food intake, normal dietary intake, indicators of iron status and plasma vitamin D levels.

RESULTS

Plasma vitamin D values are lower in the three groups of Asian children than values reported for children of a similar age in the National Diet and Nutrition Survey. Between one third and a half of children with a low haemoglobin also had low plasma vitamin D values; there was a significant association between failure to take a vitamin supplement, chapati consumption and low vitamin D values.

CONCLUSIONS

It is particularly important that pre-school Asian children receive a vitamin D supplement. Children with low haemoglobin values should be screened for vitamin D deficiency.

Staff support for mothers to provide breast milk in pediatric hospitals and neonatal units

This paper reports on two surveys of nurses and midwives working in a large pediatric hospital and three neonatal units in London, England, regarding support for mothers to provide breast milk. One hundred and twenty-two pediatric staff and 55 neonatal staff returned the questionnaires. Fifty-three percent of pediatric staff had received no training in breastfeeding during or after nursing school. Twenty-two percent of neonatal staff had no relevant training, yet they frequently were asked to help mothers in providing breast milk for their infant. Some respondents demonstrated lack of relevant knowledge including the importance of breast milk, ideal frequencies for milk expression, and the potential to establish lactation at any time. There was a wide range of comments on the barriers in providing breast milk. These results illustrate the need for appropriate breastfeeding policies and staff training. There is a particular lack of studies based in the United Kingdom on breastfeeding in pediatric units. It is hoped that this article will generate discussion among staff about the breastfeeding support they offer and ways to strengthen it.

Recent trends in infant nutrition

Two recent studies have been carried out on the feeding practices of infants in the UK. The national survey of infant feeding reveals that although overall breast-feeding rates have improved over recent years, rates among sectors of the population with low rates have not improved. A survey of infants of Asian parentage living in the UK showed high initial rates of breast-feeding that declined until at age 4 mo they matched those of the general population. Breast-feeding rates among mothers of preterm infants has improved, but studies reveal that there is potential to improve these rates further. Mothers require practical help with breast-feeding and health care professionals need to improve practical skills to meet this need.

Absence of linkage of the epithelial sodium channel to hypertension in black Caribbeans

Hypertensives of African origin have low-renin, sodium-sensitive blood pressure and respond poorly to treatment with angiotensin converting enzyme inhibitors. The epithelial sodium channel may be important in the pathogenesis of essential hypertension in this population. This is supported by the identification of mutations within this channel, which lead to excess sodium reabsorption and hypertension in Liddle's syndrome. In this study we tested whether there was linkage of the genes encoding the three subunits of the epithelial sodium channel to essential hypertension in 63 affected sibling pairs of West African origin from St. Vincent and the Grenadines. We found no support for linkage of the epithelial sodium channel to essential hypertension in this population. However, further studies will be needed in larger populations of African ancestry to exclude a contribution of the genes encoding the epithelial sodium channel to hypertension.

Noninvasive quantification of the cerebral metabolic rate for glucose using positron emission tomography, 18F-fluoro-2-deoxyglucose, the Patlak method, and an image-derived input function

The authors developed and tested a method for the noninvasive quantification of the cerebral metabolic rate for glucose (CMRglc) using positron emission tomography (PET), 18F-fluoro-2-deoxyglucose, the Patlak method, and an image-derived input function. Dynamic PET data acquired 12 to 48 seconds after rapid tracer injection were summed to identify carotid artery regions of interest (ROIs). The input function then was generated from the carotid artery ROIs. To correct spillover, the early summed image was superimposed over the last PET frame, a tissue ROI was drawn around the carotid arteries, and a tissue time activity curve (TAC) was generated. Three venous samples were drawn from the tracer injection site at a later time and used for the spillover and partial volume correction by non-negative least squares method. Twenty-six patient data sets were studied. It was found that the image-derived input function was comparable in shape and magnitude to the one obtained by arterial blood sampling. Moreover, no significant difference was found between CMRglc estimated by the Patlak method using either the arterial blood sampling data or the image-derived input function.

An evaluation of rectal mucosal proliferation measure variability sources in the polyp prevention trial: can we detect informative differences among individuals' proliferation measures amid the noise?

We assessed components of total variability of bromodeoxyuridine (BrdUrd) and proliferating cell nuclear antigen (PCNA) assays of rectal mucosal proliferation in a subset of 390 participants from the U. S. National Cancer Institute's multicenter Polyp Prevention Trial. Biopsies were blindly double-scored by two technicians. For those participants for whom at least one evaluable biopsy was obtained, a mean of 2.0 and 2.6 biopsies, and 6.2 and 8.7 crypts/biopsy were evaluated, respectively, with the BrdUrd and PCNA assays. Factors such as clinical center, scorer, and month of biopsy collection significantly affected the observed values of the labeling index (LI) and proliferative height (PH). Therefore, it is essential to control or adjust for these variables in proliferation studies. Sources of random variation for LI and PH measures remaining after the aforementioned factors include between-participant variation and several sources of within-participant variation, including variation over time, between biopsies, and between multiple measurements on the same biopsy. Both LI and PH measurements exhibited substantial variability over time, between biopsies, and from reading-to-reading of the same biopsy. When other sources of variability have been accounted for, the PCNA LI seems to have little between-participant variation. This brings into question its utility as a marker in colorectal cancer studies. The PCNA PH showed significant between-participant variability and may hold some promise as a useful marker in colorectal cancer studies. Results for BrdUrd were less conclusive. The BrdUrd LI showed marginally significant between-participant variation, whereas the corresponding variation for PH was nonsignificant.

Undergraduate teaching in a day surgery unit: a 2-year evaluation

Medical schools are having to adapt their teaching in response to the reduction in inpatient availability and the increase in outpatient and community care. A surgical course for first clinical-year undergraduate medical students was established in the day surgery unit at King's College School of Medicine and Dentistry in 1995. It was considered desirable because of the shift to day-case surgery, and proved feasible to run (Seabrook et al. 1997a). The course is taken by one-third of the annual intake of 120 students. A formal evaluation was undertaken comprising comparison of student performance in end-of-year clinical and multiple choice examinations and of acceptability to students, teachers and managers. The results showed no significant differences in performance between students who had taken the day-surgery course and those on other surgical attachments. Students' satisfaction with the course was significantly higher on nine individual criteria and lower on four criteria. The teaching was positively viewed by teachers and managers, despite having costs as well as benefits. We conclude that day-surgery centres can be used successfully to teach medical undergraduates. Experience in both inpatient and day-case environments should benefit students by reflecting more closely the reality of current surgical care.

Generalized linear least squares method for fast generation of myocardial blood flow parametric images with N-13 ammonia PET

In this paper, we developed and tested strategies for estimating myocardial blood flow (MBF) and generating MBF parametric images using positron emission tomography (PET), N-13 ammonia, and the generalized linear least square (GLLS) method. GLLS was generalized to the general linear compartment model, modified for the correction of spillover, validated using simulated N-13 ammonia data, and examined using PET data from several patient studies. In comparison to the standard model-fitting procedure, the GLLS method provided similar accuracy and superior computational speed.

Prospective investigation of positron emission tomography in lung nodules

PURPOSE

Solitary pulmonary nodules (SPNs) are commonly identified by chest radiographs and computed tomography (CT). Biopsies are often performed to evaluate the nodules further. An accurate, noninvasive diagnostic test could avoid the morbidity and costs of invasive tissue sampling. We evaluated the ability of fluorine-18 deoxyglucose positron emission tomography (FDG-PET) to discriminate between benign and malignant pulmonary nodules in a prospective, multicenter trial.

METHODS

Eighty-nine patients who had newly identified indeterminate SPNs on chest radiographs and CT were evaluated with FDG-PET. PET data were analyzed semiquantitatively by calculating standardized uptake values (SUVs) as an index of FDG accumulation and also by a visual scoring method. PET results were compared with pathology results.

RESULTS

Sixty SPNs were malignant and 29 were benign. Using SUV data, PET had an overall sensitivity and specificity for detection of malignant nodules of 92% and 90%. Visual analysis provided a slightly higher, but not statistically significant, sensitivity of 98% and lower specificity of 69%. For SPNs < or = 1.5 cm (34 of 89), the sensitivity and specificity of SUV and visual analysis were 80% and 95% and 100% and 74%, respectively.

CONCLUSION

FDG-PET can accurately characterize indeterminate SPNs. PET imaging provides a noninvasive method to evaluate indeterminate SPNs, which can reduce the need for invasive tissue biopsy.

Growth and morphological transformations of Helicobacter pylori in broth media

Helicobacter pylori, a cause of peptic ulcer disease and certain types of gastric cancers, has usually been cultured on diverse agar-based media, resulting in a requirement for 2 to 4 days of growth at 37 degrees C. We have developed a novel broth medium consisting of a base medium supplemented with 2% newborn calf serum, Mg2+, Cu2+, Fe2+, Zn2+, Mn2+, and 1 mg of lysed human erythrocytes per ml. This medium supports rapid growth of H. pylori, with a doubling time of about 50 min. Optimal growth was obtained in a pH range higher than that supporting most other gram-negative bacteria (at pH 8.5). H. pylori cultured in this supplemented broth retains the spiral morphology seen in both histological sections and cultures from agar-based media and also retains a high urease activity. After 18 h in this broth, H. pylori transforms to a coccal form with a complete loss of urease activity. Previously these cocci have been reported to be senescent, since they could not be subcultured on agar medium. Our experiments suggest that some of the cocci can revert back to the spiral morphology with full recovery of urease activity when subcultured in fresh microaerobic broth medium.

Everyday problem solving in elderly women: contributions of residence, perceived control, and age

This study examined the use of relativistic operations in everyday problem solving by elderly women. Thirty-two community residents and 32 nursing hostel residents aged between 65-90 years participated. Structured interviews canvassed the role of residence and other factors thought to contribute to the maintenance of problem-solving skills. Path analysis was used to test the developed model of the influences of age, engagement in problem-solving activities, control orientation, problem familiarity and residence on the use of relativistic operations. Partial support was found for the proposed model. Community residents used significantly more relativistic operations to solve the problems than did hostel residents. A revised model showed that in addition to residence and control orientation, the use of relativistic operations was influenced indirectly by the level of everyday problem-solving activity, through the orientation of perceived control. Increased problem-solving activity was associated with an internal control orientation, which in turn was directly related to the use of relativistic operations. The influence of age on problem solving was indirect, through problem-solving activity and residence. Our findings provide initial evidence of the extent to which variables other than age can influence everyday problem-solving performance.

The impact of prematurity and neonatal illness on the decision to breast-feed

This paper reports on a qualitative and quantitative cross-sectional study of infant feeding practices made in three neonatal intensive care units. Findings from interviews with 44 mothers of diverse ethnic origin, social class, age and gestation at delivery are reported. All the mothers interviewed had at some time provided breast milk and rates of breast-feeding on these units were higher than the national average. Eight mothers reported changing their mind about feeding methods after their baby was admitted, including three changes from formula to breast-feeding. Mothers' perceptions with regard to milk expression and their expressing history gave indications of factors underlying decisions to provide breast milk and the quality of support to do so. While mothers considered overall support to have been good, notably 35% of mothers had themselves suggested that they express milk, nearly half did not start expressing for 2 or more days, 43% expressed fewer than four times a day and 48% of mothers had received conflicting advice. There were some difficulties with both the hospital facilities and with expressing milk at home. There is a need for more consistent advice and practical help to be given to mothers.

Teaching and learning in day surgery units: a UK survey

Recent increases in day case surgery offer new opportunities for medical student learning, whilst the reduction in surgical beds and length of hospital stays has reduced opportunities in traditional inpatient settings. To establish the extent and nature of undergraduate medical education in day surgery units in the UK, the authors undertook a postal questionnaire survey. Of the 227 units which replied, 45% are used for teaching. In 83% of these, students attend only single operating lists, and only 7% of units take students for more than 1 day per week. This suggests that students have very limited teaching in day surgery units. Diagnosis, common surgical procedures and rehabilitation are increasingly carried out in outpatient, day case and community settings. These may be missed by students unless educational programmes are responsive to trends in health care delivery. Day surgery units could play an increased role in medical education.

Pheochromocytoma

OBJECTIVE

To characterize the symptoms associated with pheochromocytoma and discuss the diagnosis and management of this tumor.

METHODS

We review the clinical manifestations in patients with pheochromocytoma, the biochemical and imaging studies recommended for diagnosis and localization of the tumor, and the available strategies for treatment.

RESULTS

Pheochromocytoma is a tumor of chromaffin cells that originates in either the adrenal medulla or the extra-adrenal sympathetic tissues. It is usually unilateral and benign. Frequent initial symptoms include headache, sweating, and palpitations, with or without increased blood pressure. In many patients, hypertension is accelerated during a paroxysm. Pheochromocytoma may also occur as a part of multiple endocrine neoplasia type IIA and B. Several common syndromes, such as panic disorders and hyperthyroidism, may mimic pheochromocytoma; however, pheochromocytoma should be suspected in the presence of hypertension, tachycardia, and throbbing headache, especially occurring as paroxysmal episodes. The physiologic diagnosis of pheochromocytoma is established by biochemical tests of levels of plasma and urinary catecholamines or their metabolites (or both). In most patients, anatomic localization is achieved with computed tomography or magnetic resonance imaging, metaiodobenzylguanidine scintigraphy, labeled somatostatin scans, or positron emission tomography. The management preferentially includes surgical removal of the pheochromocytoma after preparation with appropriate medical therapy to avoid hypertensive crisis during the perioperative period. Patients with contraindications to a major surgical procedure or with malignant pheochromocytoma and metastatic disease, however, may be treated with multiple drugs--for example, alpha- and beta-adrenergic blockers and direct vasodilators to neutralize the effects of high levels of circulating catecholamines and alpha-methyl-metatyrosine to inhibit catecholamine synthesis.

CONCLUSION

The presence of suggestive clinical features in patients with hypertension should prompt clinicians to undertake appropriate diagnostic testing because surgical resection of a pheochromocytoma will yield a cure in many cases.

The atrial natriuretic peptide gene and essential hypertension in African-Caribbeans from St Vincent and the Grenadines

Atrial natriuretic peptide (ANP) which alters sodium balance, blood volume and vascular tone represents an important candidate for investigating the genetic basis of essential hypertension (EH). Accordingly, we have studied Bgl1 and Xho1 restriction fragment length polymorphisms (RFLPs) of the ANP gene in 147 hypertensive, 141 normotensive and 67 population-based control subjects from a homogenous population of West African origin from St Vincent and the Grenadines. We found no association of either Bgl1 and Xho1 RFLPs with EH. This study suggests that the ANP locus may not exert a major gene effect on EH amongst the black people of St Vincent and the Grenadines.

Application of ambulatory infusion devices in infusional cancer chemotherapy: a model for nursing management

Optimal support of the patient receiving infusional cancer chemotherapy (ICC) in the home setting is partially dependent on the provision of an infusional device that offers minimal complexity and maximal reliability and safety. The selection of the appropriate device is vital to positive patient outcomes and to the comfort level of both patient and care providers. This article presents issues and considerations in the selection of infusion devices and the nursing role in the management of patients utilizing such devices. Aspects of nursing management are presented from the perspective of The Cancer Center of Boston (TCC) model.

Intracellular calcium and calcineurin regulate neutrophil motility on vitronectin through a receptor identified by antibodies to integrins alphav and beta3

Buffering of intracellular calcium ([Ca2+]i) or inhibition of the calcium/calmodulin-dependent phosphatase, calcineurin, results in neutrophils being unable to detach from vitronectin with a consequent loss of motility. Treatment of [Ca2+]i-buffered or calcineurin-inhibited neutrophils with monoclonal antibodies (MoAbs) to beta3 or alphav beta3 integrins allowed neutrophils to detach and restored motility. Quantitative immunofluorescence and flow cytometry showed that MoAbs specific for beta3, alphav, or alphav beta3 integrins bind to neutrophils. Immunolocalization studies using antibodies to the highly conserved cytoplasmic domains of alphav and beta3 also identified the receptor on neutrophils. Whereas antibodies to alphav, alphav beta3, and beta3 recognized the receptor in intact cells, only the beta3 MoAb immunoprecipitated the receptor from a neutrophil cell lysate. The alpha subunit co-immunoprecipitated by the beta3 antibody reacted with an antibody to alphav by Western blot. Peptide maps of V8 protease digests showed a strong similarity in alpha and beta chains precipitated by antibodies to beta3 from neutrophils and endothelial cells. These results indicate that [Ca2+]i and calcineurin regulate neutrophil motility on vitronectin through an alphav beta3-like receptor. Although we cannot rule out the possibility that neutrophils have an isoform of alphav, such an isoform would have to be similar enough to react with alphav- and alphav beta3-specific MoAbs in intact cells.

Linkage of the angiotensinogen gene locus to human essential hypertension in African Caribbeans

The renin-angiotensin system regulates blood pressure and sodium balance. The angiotensinogen gene which encodes the key substrate within this system has been linked to essential hypertension in White Europeans. It has been suggested that people of West African ancestry may have a different genetic basis for hypertension. In this study we have tested whether there is linkage of the angiotensinogen gene to essential hypertension in African Caribbeans from St. Vincent and the Grenadines. DNA from 63 affected sibling pairs with hypertension was tested for linkage by analyzing whether there was excess allele sharing among siblings genotyped using an angiotensinogen dinucleotide repeat sequence. There was significant support for linkage (T = 3.07, P = 0.001) and association of this locus to hypertension (chi 2 = 50.2, 12 degrees of freedom, P << 0.001). A DNA polymorphism which alters methionine to threonine at position 235 (M235T) within the angiotensinogen peptide has been associated previously with hypertension. However, we found no association of this variant with hypertension in this study. These findings provide support for linkage and association of the angiotensinogen locus to hypertension in African Caribbeans and suggest some similarities in the genetic basis of essential hypertension in populations of different ethnicity.

Absence of genetic linkage between polymorphisms of the insulin receptor gene and essential hypertension

This study evaluated whether hypertensive siblings had excess sharing of RsaI and SstI alleles of the insulin receptor gene compared with a random population. Thirty families consisting of 60 affected individuals with established hypertension were genotyped for the RsaI and SstI restriction fragment length polymorphisms and the resulting genotype data was analysed using the affected pedigree member method of linkage analysis. The hypertensive siblings were found to have increased sharing of INSR alleles; however, this linkage could not be confirmed using a maximum LOD score method. Thus, the results from this study do not support a role for the INSR gene in the genesis of essential hypertension in the population studied.

Hawksley random zero sphygmomanometer versus the standard sphygmomanometer: an investigation of mechanisms

There has been recent controversy over the accuracy of the Hawksley random zero sphygmomanometer (RZS). In most instances, there has been a bias towards lower recordings with the RZS. In an attempt to identify the mechanism, we designed a study to test the hypothesis that biased error is due to: (1) the magnitude of the random zero; and (2) the magnitude of the pressure being recorded. A RZS (60 mm Hg zero UK version) was connected via a Y-tube to a standard mercury sphygmomanometer (SMS). The circumference of the cam responsible for the variable reservoir size in the RZS was marked into quarters. Within each 10 mm Hg band from 300 to 60 mm Hg, 12 paired readings were taken randomly: three within each of the four quarters of the cam circumference. The mean SMS value was 148.8 vs. 148.2 mm Hg for the RZS. Although of minimal biological significance this difference was highly significant (t = 6.2; p < 0.0001). Our findings fail to confirm the difference between RZS and SMS previously reported and we did not find any evidence of a relation in the difference between SMS and RZS and either the random zero value or the height of the blood pressure. Our findings suggest that if the RZS does under record BP versus the SMS it may relate to a patient-machine interaction not detectable in our system.

Lack of effect of recombinant platelet-derived growth factor on human neutrophil function

Platelet-derived growth factor (PDGF) has been reported to induce chemotaxis, degranulation, and superoxide anion generation, and to increase the expression of CD11b/CD18 in human neutrophils; hence, it has been proposed as an important regulator of neutrophil function. Most of the studies on PDGF, however, have been complicated by the use of nonrecombinant PDGF or the use of mixed leukocyte cell preparations. Assessment of the effects of recombinant human PDGF-AB or -BB which display agonist activity against both PDGF receptor subtypes failed to demonstrate any effect of this peptide on neutrophil shape change, respiratory burst activity, CD11/CD18, or CD62-L expression, inositol 1,4,5-trisphosphate accumulation, or phosphorylation of mitogen-activated protein kinase. This apparent lack of effect of PDGF was consistent with our findings that neutrophils display no specific 125I-PDGF-AB or -BB binding and lack detectable mRNA for PDGF alpha-receptor and beta-receptors. These data indicate that human neutrophils do not possess functional PDGF receptors and question previous reports of a functional effect of this peptide in these cells.

Lack of effect of recombinant platelet-derived growth factor on human neutrophil function

Platelet-derived growth factor (PDGF) has been reported to induce chemotaxis, degranulation, and superoxide anion generation, and to increase the expression of CD11b/CD18 in human neutrophils; hence, it has been proposed as an important regulator of neutrophil function. Most of the studies on PDGF, however, have been complicated by the use of nonrecombinant PDGF or the use of mixed leukocyte cell preparations. Assessment of the effects of recombinant human PDGF-AB or -BB which display agonist activity against both PDGF receptor subtypes failed to demonstrate any effect of this peptide on neutrophil shape change, respiratory burst activity, CD11/CD18, or CD62-L expression, inositol 1,4,5-trisphosphate accumulation, or phosphorylation of mitogen-activated protein kinase. This apparent lack of effect of PDGF was consistent with our findings that neutrophils display no specific 125I-PDGF-AB or -BB binding and lack detectable mRNA for PDGF alpha-receptor and beta-receptors. These data indicate that human neutrophils do not possess functional PDGF receptors and question previous reports of a functional effect of this peptide in these cells.

Rapid metabolic phenotypes for acetyltransferase and cytochrome P4501A2 and putative exposure to food-borne heterocyclic amines increase the risk for colorectal cancer or polyps

The metabolic activation of food-borne heterocyclic amines to colon carcinogens in humans is hypothesized to occur via N-oxidation followed by O-acetylation to form the N-acetoxy arylamine that binds to DNA to give carcinogen-DNA adducts. These steps are catalyzed by hepatic cytochrome P4501A2 (CYP1A2) and acetyltransferase-2 (NAT-2), respectively, which are known to be polymorphic in humans. On the basis of this proposed metabolic activation pathway, patients at greatest risk to develop colorectal cancer or nonfamilial polyps should be those who possess both the rapid NAT-2 and rapid CYP1A2 phenotypes and are exposed to high dietary levels of carcinogenic heterocyclic amines. Using a method that involves caffeine administration and high pressure liquid chromatographic analysis of urinary metabolites, we have determined the CYP1A2 and NAT-2 phenotypes of 205 controls and 75 cancer/polyp cases. Exposure information was obtained using a dietary and health habits questionnaire. Both the rapid CYP1A2 and rapid NAT2 phenotypes were each slightly more prevalent in cases versus controls (57% and 52% versus 41% and 45%, respectively). However, the combined rapid CYP1A2-rapid NAT-2 phenotype was found in 35% of cases and only 16% of the controls, giving an odds ratio of 2.79 (P = 0.002). Univariate analysis of the questionnaire indicated that age, rapid-rapid phenotype, and consumption of well done red meat were associated with increased risk of colorectal neoplasia. Furthermore, a logistic regression model that included age (as a continuous variable), consumption of well done red meat, and rapid-rapid phenotype as independent covariates gave odds ratios of 1.08, 2.08, and 2.91, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of moderate dietary protein restriction on the progression of overt diabetic nephropathy: a 6-mo prospective study

To assess whether moderate dietary protein restriction can delay the progression of overt diabetic nephropathy, 22 subjects with insulin-dependent diabetes mellitus were randomly assigned to an unrestricted protein diet (> 1.6 g.kg body wt-1.d-1) or a moderately protein-restricted diet (0.8 g.kg body wt-1.d-1) and followed prospectively for six mo. Direct isotope methods were used to assess renal function. Protein intake was assessed by measurement of urinary urea nitrogen. The two groups were well-matched for age, sex, duration of diabetes, glycemic control, blood pressure, and degree of renal insufficiency. Patients consuming the unrestricted protein diet (n = 11) showed a progressive decline in glomerular filtration rate of 1.3 mL.min-1.mo-1 with no change in proteinuria. Patients consuming the moderately protein-restricted diet showed a marked decrease in the degree of proteinuria (2.15-1.13 g/d, P = 0.036) and a stabilization of glomerular filtration rate. This occurred independently of changes in blood pressure or glycemic control. Moderate dietary protein restriction can ameliorate progression of overt diabetic nephropathy.

Linkage of the angiotensinogen gene to essential hypertension

BACKGROUND

The renin-angiotensin system is a powerful pressor system with a major influence on salt and water homeostasis. Angiotensinogen (also called renin substrate) is a key component of this system; it is cleaved by renin to yield angiotensin I, which is then cleaved by angiotensin-converting enzyme to yield angiotensin II. The observation that plasma angiotensinogen levels correlate with blood pressure and track through families suggests that angiotensinogen may have a role in essential hypertension. We therefore investigated whether there is linkage between the angiotensinogen gene on chromosome 1q42-43 and essential hypertension.

METHODS

Samples of DNA from 63 white European families in which two or more members had essential hypertension were tested for linkage of the angiotensinogen gene to this disorder. Affected cousins, nephews, nieces, and half-siblings were included when possible. To test for linkage, we used as a marker a dinucleotide-repeat sequence flanking this gene, and we employed the affected-pedigree-member method of linkage analysis. Two molecular variants of the angiotensinogen gene, one encoding threonine instead of methionine at position 235 (M235T) and the other encoding methionine rather than threonine at position 174 (T174M), were also tested for possible association with essential hypertension.

RESULTS

We found significant linkage (t = 5.00, P < 0.001) and association (chi-square = 53.3, P < 0.001) of the angiotensinogen-gene locus to essential hypertension in the 63 multiplex families. This linkage was consistently maintained in the subgroup of subjects with diastolic pressure above 100 mm Hg and in the subgroups classified according to sex. It has been proposed previously that T174M and M235T are associated with essential hypertension. However, we found no association in our population between either polymorphism and this disorder.

CONCLUSIONS

This study provides strong and consistent support for the linkage to essential hypertension of regions within or close to the angiotensinogen gene. Precisely how mutations in this region may result in hypertension remains to be determined.