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Biomedical subjects

D K White

Publications and source records attributed to D K White.

At least 19 recordsLinked to original sources
PubMed2004

Lymphocyte apoptosis in acute respiratory syncytial virus bronchiolitis.

Respiratory syncytial virus (RSV) infection may have an effect on the development of T cell memory responses. RSV bronchiolitis in infants is associated with a transient decline in circulating lymphocytes. We hypothesized that the mechanism underlying this lymphopenia is apoptosis. Blood was taken from 32 infants during primary RSV bronchiolitis and three months later. Using flow cytometry, we found that absolute numbers of both CD3+/CD4+ T-helper lymphocytes (P = 0.029) and CD3+/CD8+ cytotoxic lymphocytes (CTL) (P = 0.043) were significantly reduced during acute infection. Up-regulated expression both of Fas (P < 0.001) and tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) receptor (P < 0.001) was found during acute illness on both CD3+/CD4+ and CD3+/CD8+ lymphocytes, when compared with convalescent samples. Expression of Fas on CD4+ lymphocytes was inversely related to CD4+ number (P = 0.03). Plasma levels of soluble Fas ligand (P = 0.028) and caspase-1 (P = 0.037), determined by enzyme-linked immunosorbent assay, were increased during bronchiolitis. Plasma interleukin-18, a product of caspase-1 activity, was not raised. Taken together, these data suggest that in acute RSV infection, CD4+ helper lymphocytes and CD8+ cytotoxic lymphocytes are primed to undergo apoptosis. This is a mechanism through which lymphopenia may occur and T cell memory may be altered.

Age Factors↗
PubMed2004

Severe head injury in children: geographical range of an emergency neurosurgical practice.

OBJECTIVE: To determine the timings of regional transfer for emergency neurosurgery and intensive care after severe head injury in children, and the effective operational range of a regional service. DESIGN: Prospective observational study of admissions to a regional paediatric intensive care unit (PICU). SETTING: East Anglia region in England, January 2000 to December 2001, where 18 referring hospitals are within two hours road transit time from the centre. PATIENTS: 69 severely head injured children (52 boys and 17 girls, aged 8.4 (3.6 to 12.5) years). MAIN OUTCOME MEASURES: Time interval between injury and arrival at first hospital (primary transfer); timing between arrival at first hospital and arrival in PICU or the operating theatre (secondary transfer). RESULTS: Arrival in one of the 19 accident and emergency departments occurred (median, IQR) within 48 (35 to 70) minutes of the accident. After arrival, the interval of secondary transfer was 4.4 (3.2 to 5.8) hours. Children rarely received their surgery within four hours of injury; for this to occur, the geographical range of this regional practice would need to be restricted to those hospitals within about 45 minute road transit time from the centre. CONCLUSIONS: Good evidence supporting the recommendation that acute neurosurgery for the evacuation of a haematoma within four hours of injury is still scarce. The timings of care after an accident suggest that this guideline is unworkable in regions covering areas with road distance travel times in excess of 45 minutes.

Catchment Area, Health↗
PubMed2003

Pericardial effusion and cardiac tamponade as complications of neonatal long lines: are they really a problem?

AIM: To estimate the frequency of pericardial effusion/cardiac tamponade associated with the use of neonatal percutaneous long lines (PLLs) over the past five years. METHOD: A retrospective nationwide postal survey, of all neonatal and special care units in the United Kingdom. RESULTS: Eighty two cases of pericardial effusion/cardiac tamponade were reported from the five year period, during which we estimate that 46 000 PLLs were inserted. The calculated frequency of pericardial effusion/cardiac tamponade occurring with PLLs was 1.8/1000 lines. There were 30 deaths, giving a fatality rate after pericardial effusion of 0.7/1000 lines. CONCLUSIONS: Pericardial effusion/cardiac tamponade is a serious but infrequent complication of PLL use.

Cardiac Tamponade↗
PubMed2002

Bereavement support following sudden and unexpected death: guidelines for care.

Dealing with families who have suffered a sudden and unexpected death is a skill that may be needed by any paediatrician. Offering a bereavement follow up meeting to such families is part of accepted practice and is perceived to be of value in helping the family to come to terms with the loss. Unfortunately, there is very little guidance on the objectives for such a meeting, or the training required to help staff conduct such meetings. The nature of the work on a paediatric intensive care unit (PICU) means that staff have a greater experience of handling families in such a situation. We have reviewed our experience over the past five years following up the families of 51 children who have died suddenly and unexpectedly in our regional PICU. In doing this we have identified five key elements that we suggest are essential to a successful follow up meeting, and have supported this with case studies as illustration.

Adolescent↗
PubMed2001

Chronic fissural cheilitis: a manifestation of anterior crowding.

A 48-year-old man, otherwise in good health, was seen with a chronic painful fissure of the upper lip mucosa. For at least 2 years it had failed to respond to a variety of topical agents. Though not previously reported, the primary etiologic factor was thought to be irritation from contact with his misaligned anterior teeth. Eight months into orthodontic treatment, the lesion healed and did not return. Orthodontics included preadusted edgewise mechanics. However, the right maxillary lateral incisor was not bracketed but instead guided into position by direct contact with the archwire.

Cheilitis↗
PubMed2001

Polymorphous low-grade adenocarcinoma versus pleomorphic adenoma of minor salivary glands: resolution of a diagnostic dilemma by immunohistochemical analysis with glial fibrillary acidic protein.

OBJECTIVES: Differentiating polymorphous low-grade adenocarcinoma (PLGA) from pleomorphic adenoma (PA) in salivary gland biopsy specimens from the palatal region might be a diagnostic dilemma for the pathologist when tumors are cellular with minimal matrix material. Glial fibrillary acidic protein (GFAP), expressed by a number of cells in the mature central nervous system, is also expressed in tumors not generally considered to be of glial origin. PAs have previously been reported to strongly express GFAP. PLGAs have been examined for the expression of this protein only in small group studies with variable results. The objective of this study was to determine whether differential expression of GFAP in these 2 tumors could be diagnostically significant. STUDY DESIGN: A total of 42 PLGAs and 36 PAs, formalin-fixed and paraffin-embedded, were immunostained with rabbit polyclonal antibodies to GFAP. CNS tissue was used as a positive control. RESULTS: Results showed the 36 cases of PA to be strongly positive for GFAP. Of PLGAs, 31 were negative and 11 showed faint patchy reactivity in luminal cells. CONCLUSIONS: The results strongly support a role for GFAP as a diagnostic adjunct in the microscopic differential diagnosis of PLGA versus PA. This study is the largest investigation with consistent results to date addressing the application of this antibody to the diagnostic problem of PA versus PLGA.

Adenocarcinoma↗
PubMed2001

Sleep position and the use of soft bedding during bed sharing among African American infants at increased risk for sudden infant death syndrome.

UNLABELLED: Soft bedding increases the risk for death among prone infants. We compared the softness of beds and bedding and infant sleep position for infants sleeping alone and for those bed sharing. STUDY DESIGN: Questionnaires were used to record the bedding and sleep practices of 218 consecutive African American infants. Enrollment was prospective. Mechanical models were used in the homes of a subgroup to measure the softness of bedding and its propensity to cause rebreathing. Results were compared by using the Student t test, Mann-Whitney U test, and chi(2) analysis. RESULTS: In a cross-sectional sample of infants, at 8.2 +/- 3.3 weeks of age, 61% (133 of 218) had bed shared > or =1 of the previous 14 nights and 48.6% (106 of 218) had bed shared the night before. Breast-feeding rates were not different for bed sharers and those sleeping alone. The rates of maternal smoking for both groups were low (13.6% vs 11.8%). Comforters, pillows, and waterbeds were more commonly used beneath bed-sharing infants. Bed sharers were twice as likely to habitually be placed prone for sleep (18% vs 9%). In the subgroup studied in their homes (13 bed sharing, 19 alone), the shared beds were softer (P <.0001) and could cause more rebreathing (P =.007). CONCLUSIONS: Infants at increased risk for sudden infant death syndrome, by sociodemographic criteria, who also bed share are more likely to sleep prone and to use softer beds. These findings may explain part of the risk associated with bed sharing among US infants, a risk that appears to be independent of the effects of maternal smoking.

Black or African American↗
PubMed2001

Accessory salivary tissue in the mylohyoid boutonnière: a clinical and radiologic pseudolesion of the oral cavity.

BACKGROUND AND PURPOSE: Though classically depicted as a continuous muscular barrier between the sublingual and submandibular spaces, the mylohyoid muscle is often discontinuous. These areas of discontinuity may contain fat, blood vessels, salivary tissue, or combinations thereof that may be mistaken both clinically and radiologically for pathologic abnormalities. We sought to demonstrate the prevalence and radiologic appearance of dehiscence of the mylohyoid muscle. METHODS: One hundred axial, contrast-enhanced CT studies of the neck, obtained over a 10-month period, were retrospectively reviewed. Inclusion criteria included 3-mm-thick slices and absence of pathologic abnormalities or surgical changes in the oral cavity. Scans were assessed for the presence and contents of mylohyoid defects such as accessory salivary tissue, defined as nonlymphoid tissue within defects in the mylohyoid, having attenuation and enhancement characteristics similar to those of orthotopic sublingual and submandibular salivary tissue. RESULTS: Mylohyoid defects were identified in 77 of 100 individuals. The deficiencies were bilateral in 67% and unilateral in 33%. Accessory salivary tissue was identified in 37 of 100. Fat and blood vessels were commonly identified within the mylohyoid defects. Sixty-one percent of the defects contained only fat. Thirty-five percent of the defects contained blood vessels. CONCLUSION: Deficiencies in the mylohyoid muscle were visible in 77% of individuals who underwent scanning. The defects may contain fat, blood vessels, salivary tissue, or all three characteristics. Accessory salivary tissue was identified in 37% of individuals who underwent scanning. Recognition of mylohyoid deficiencies and the typical appearance of accessory salivary tissue will allow accurate diagnosis of this benign, anatomic variant.

Adipose Tissue↗
PubMed1999

Intraosseous fibrous lesions of the jaws: a manifestation of tuberous sclerosis.

Four patients previously diagnosed with tuberous sclerosis are reported with intraosseous fibrous lesions of the jaws. Review of the literature revealed comparable pathosis occurring in extragnathic bones and several previous reports of similar lesions within the jaws. Therefore, these intraosseous fibrous proliferations are thought to represent an intraoral manifestation of tuberous sclerosis and not coincidental findings. In all 4 cases, the tumors demonstrated significant collagenization with numerous interspersed plump fibroblasts. Although histopathologically similar, the features of the lesions are not specific and also can be found in desmoplastic fibromas and simple odontogenic fibromas. The definitive diagnosis requires appropriate clinicopathologic correlation.

Adolescent↗
PubMed1999

Leukoplakia of the maxillary vestibule--an association with Viadent?

OBJECTIVE: This report investigates a possible correlation between chronic use of Viadent products and the subsequent development of leukoplakia in the maxillary vestibule. STUDY DESIGN: A retrospective review of 88 patients with leukoplakia of the maxillary vestibule is presented. Prevalence of Viadent use was determined in this group and in a group of 100 randomly selected adults who presented themselves for routine preadmission screening at a dental school. RESULTS: Of the patients diagnosed with leukoplakia of the maxillary vestibule, 84.1% reported having used Viadent, whereas the prevalence of use was only 3% in the 100 randomly selected adults. CONCLUSIONS: Use of Viadent products appears to be associated with an increased prevalence of leukoplakia in the maxillary vestibule.

Adult↗
PubMed1999

Continuous neonatal blood gas monitoring using a multiparameter intra-arterial sensor.

AIMS: To compare arterial blood gas (ABG) readings obtained with a multiparameter intra-arterial sensor with those from an ABG analyser. METHODS: An MPIAS with the ability to measure continuously pH, PaCO2, and PaO2 was introduced via an umbilical arterial catheter in 27 neonates requiring intensive care. They underwent 3260 hours of MPIAS monitoring, during which 753 ABG readings were performed. RESULTS: Overall bias (mean difference: MPIAS-ABG) and precision (standard deviation of differences) values were: -0.002 and 0.022, respectively, for pH; +0.26 and 0.52 for PaCO2 (kPa); and -0.19 and 0.99 for PaO2 (kPa). This gave 95% limits of agreement as: -0.047 to +0.042 for pH, -0.76 to +1.28 kPa for PaCO2, and -2.13 to +1.75 kDa for PaO2. For each variable, precision across readings from the same individual was better than overall precision for all data. No complications related to the use of the catheter were observed. CONCLUSIONS: Continuous MPIAS ABG monitoring is an exciting development, with the potential to reduce blood transfusions and improve ABG homeostasis.

Blood Gas Analysis↗
PubMed1999

Growth of lungs after transplantation in infants and in children younger than 3 years of age.

We report serial measurements of lung volume and airflow in small children after lung transplantation. We expected that immature lungs could grow and develop normal volumes after transplantation, despite denervation and immunosuppression. At predetermined intervals, functional residual capacity (FRC) and forced expiratory flow were measured 86 times in 23 recipients younger than 3 yr of age (age at transplant, 13.2 +/- 8.4 mo; range, 2 to 30 mo). FRC was measured using open-circuit N2 washout. Maximal flow at FRC by rapid thoracoabdominal compression was used to distinguish between infants with and those without airflow obstruction. The slope of FRC (in milliliters) versus body length (in centimeters) for all 23 recipients studied was 8.63. For those children without obstruction (flow at FRC >/= 0.9 FRC/s, n = 16), the slope of FRC versus length was 6.61. The coefficient of variation for FRC measurements for all infants was 3.90 +/- 2.80% (range, 0.3 to 16.9%). We conclude that in the absence of significant airflow obstruction the volume of transplanted immature lungs increases at a rate similar to that reported in normal infants.

Body Height↗
PubMed1999

MR evaluation of vestibulocochlear anomalies associated with large endolymphatic duct and sac.

BACKGROUND AND PURPOSE: Large endolymphatic duct and sac (LEDS) is one of the most common anomalies seen in patients with congenital sensorineural hearing loss (SNHL), and is known to occur with other inner ear findings. Our purpose was to use high-resolution T2-weighted fast spin-echo (FSE) MR imaging to describe the features and prevalence of specific anomalies that occur in association with LEDS. METHODS: We retrospectively reviewed MR images of the inner ear obtained in 63 patients with LEDS and in 60 control subjects. We evaluated each image for features of cochlear and vestibular dysplasia, including deficiency of the cochlear modiolus, gross cochlear dysmorphism, asymmetry of the cochlear scalar chambers, enlargement of the membranous vestibule, gross vestibular dysmorphism, and abnormality of the semicircular canals (SCC). RESULTS: Cochlear anomalies were present in 76% of ears with LEDS. Modiolar deficiency, gross dysmorphism, and scalar asymmetry were seen in 94%, 71%, and 65% of abnormal cochleas, respectively. Vestibular abnormalities were present in 40% of ears with LEDS. Simple enlargement, gross dysmorphism, and distortion of the lateral SCC were seen in 84%, 16%, and 32% of abnormal vestibules, respectively. CONCLUSION: Coexistent cochlear anomalies, vestibular anomalies, or both are present in most ears with LEDS, and appear as a spectrum of lesions, ranging from subtle dymorphism to overt dysplasia. The presence of coexistent anomalies in LEDS affects treatment decisions and prognosis. Newer techniques of high-resolution FSE MR imaging provide a means of exquisite characterization of LEDS, as well as more sensitive detection of associated vestibulocochlear anomalies.

Cochlea↗
PubMed1998

Softness and potential to cause rebreathing: Differences in bedding used by infants at high and low risk for sudden infant death syndrome.

OBJECTIVE: This study was carried out to determine whether bedding used by infants, who are at either high or low risk for sudden infant death syndrome (SIDS), differs in physical properties favoring rebreathing of exhaled gases. STUDY DESIGN: We compared softness and limitation of carbon dioxide dispersal by bedding, using a mechanical model. A questionnaire was used to describe sociodemographic risk factors and sleep practices; bedding was studied in homes with a model positioned where each infant was found sleeping that morning. RESULTS: The groups differed with respect to five sociodemographic risk factors (p values all < or = 0.0001). In addition, infants at higher risk were more likely to have been placed to sleep prone (46%, p = 0.02) by parents who were less likely to be aware of the risk associated with the prone position (62% aware, p = 0.005). Infants at higher risk had softer bedding (p < 0.0001, 54.1+/-17.2 cm2 vs 33.7+/-7.7 cm2 in contact with model), which caused more limitation of carbon dioxide dispersal (p = 0.008; CO2 retained, 0.60%+/-0.15% vs 0.34%+/-0.05%). CONCLUSIONS: A series of infants who are at high risk for SIDS because of sociodemographic factors more often sleep on bedding that has physical properties favoring rebreathing, and their parents are less often aware of the risk associated with prone sleeping.

Bedding and Linens↗
PubMed1998

Infant Flow Driver or single prong nasal continuous positive airway pressure: short-term physiological effects.

The effectiveness of single prong nasal continuous positive airway pressure (CPAP) was compared with the Infant Flow Driver (IFD) in a crossover study in 20 neonates treated with > or = 30% oxygen by nasal CPAP. They were randomized to the device used at the start of the study. Each infant was studied for four consecutive 2-h periods alternating between single prong nasal CPAP and the IFD. The FiO2 from the IFD read 0.02 higher than the same setting on the ventilators used for single prong nasal CPAP. The IFD improved the mean (95% CI) of the FiO2 by 0.05 (0.02-0.08), p = 0.008. Taking into account the systematic error in the FiO2 between the devices the real mean improvement in FiO2 produced by the IFD was 0.03 (-0.005 to 0.06), p=0.09. There were no significant differences in respiratory rate, heart rate, blood pressure or comfort score of infants during periods of single nasal prong CPAP compared with periods on the IFD.

Cross-Sectional Studies↗
PubMed1997

No health for all without better trained management.

This article notes that existing health professionals and managers constitute the first 'generation' working in a world where Health for All is a practical possibility because, if founded on community-based public and primary health care with hospitals in support and good intersectoral help, we now have the appropriate technology, access to finance and adequate numbers of health workers. What we still lack are sufficient health professionals, at all levels, with the managerial skills and experience to apply the technology, generate the funding and motivate the staff; making full use of community involvement, the co-operation of other sectors and good relationships with local and central government. Management can be learned both at the workplace and in the training room, and from the managers a few of them will emerge as leaders, with the vision to secure the willing support of others in reaching worthwhile health goals. A very useful publication is the Training Manual on Management of Human Resources for Health, WHO/EDUC/93.201 from World Health Organisation, Geneva, Switzerland. The paper closes with examples illustrating four principles for health management development: finding key points of entry; reaching large numbers; accelerating national self-sufficiency; and international.

Administrative Personnel↗
PubMed1996

A preliminary study of reconstruction of the monkey temporomandibular joint with autogenous tissues.

PURPOSE: This study investigated the ability of autogenous pericranium-muscle and cranial bone to restore form and function of the temporomandibular joint (TMJ). MATERIALS AND METHODS: A right TMJ discectomy, condylectomy, vertical ramus osteotomy with superior repositioning of the proximal fragment, and a cranial bone graft to the mandibular angle were performed in 12 cynomolgus monkeys. Clinical, histologic, and autoradiographic evaluation was done at intervals beginning at 3 days and continuing up to 78 weeks. RESULTS: No significant postoperative sequela were identified in any of the monkeys. Jaw mobility and function were restored. Gross morphologic condylar changes were observed. The pericranium-muscle grafts did not differentiate into normal disc-like structures and a cartilage cap did not cover the condyle stump head. CONCLUSIONS: The results of this study suggest that the previous TMJ function was restored. However, the histologic changes observed were consistent with advanced degenerative joint disease.

Animals↗