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Biomedical subjects

D Roberts

Publications and source records attributed to D Roberts.

At least 181 records · Page 10Linked to original sources
PubMed1995

Seeding of a parotid pleomorphic adenoma.

Recurrent pleomorphic adenoma of the parotid usually occurs in the distribution of the primary procedure. There are numerous reports of widespread local recurrence and a few reported cases of distant metastases. Extensive seeding throughout the entire ipsilateral neck is rare. Treatment involves a combination of radical surgery and radiotherapy. The potential for malignant transformation demands close follow-up of younger patients particularly.

Adenoma, Pleomorphic↗
PubMed1995

The effects of low concentrations of antibiotics on epithelial damage caused by non-typable Haemophilus influenzae and bacterial morphology.

Sterile culture filtrates from non-typable Haemophilus influenzae (NTHi) grown in medium containing no antibiotics or 0.25 MIC of amoxycillin, ciprofloxacin or loracarbef were examined for their effect on the ciliary beat frequency (CBF) and structure of human respiratory epithelium. CBF slowing was significantly (P < 0.05) less with 0.25 MIC of all three antibiotics. The epithelium was significantly (P < 0.05) less disrupted with ciprofloxacin. The morphology of NTHi infecting human adenoid organ cultures after 24 h with or without 0.25 MIC of the same antibiotics was measured by scanning electron microscopy. Only ciprofloxacin caused a significant (P < 0.05) change in morphology.

Anti-Bacterial Agents↗
PubMed1995

A case of severe diabetic retinopathy in pregnancy.

Proliferative retinopathy is a recognized long-term complication of diabetes and the commonest cause of blindness in young people. There is, however, some uncertainty regarding counselling given on the continuation of pregnancy when it is complicated by retinopathy. This case is used to highlight this difficulty and to discuss management based on literature review.

Adult↗
PubMed1995

On the use of nucleic acid sequences to infer early branchings in the tree of life.

Simplifying assumptions made in various tree reconstruction methods--notably rate constancy among nucleotide sites, homogeneity, and stationarity of the substitutional processes--are clearly violated when nucleotide sequences are used to infer distant relationships. Use of tree reconstruction methods based on such oversimplified assumptions can lead to misleading results, as pointed out by previous authors. In this paper, we made use of a (discretized) gamma distribution to account for variable rates of substitution among sites and built models that allowed for unequal base frequencies in different sequences. The models were nonhomogeneous Markov-process models, assuming different patterns of substitution in different parts of the tree. Data of the small-subunit rRNAs from four species were analyzed, where base frequencies were quite different among sequences and rates of substitution were highly variable at sites. Parameters in the models were estimated by maximum likelihood, and models were compared by the likelihood-ratio test. The nonhomogeneous models provided significantly better fit to the data than homogeneous models despite their involvement of many parameters. They also appeared to produce reasonable estimation of the phylogenetic tree; in particular, they seemed able to identify the root of the tree.

Base Sequence↗
PubMed1995

Childhood injuries and the importance of documentation in the emergency department.

The purpose of this study is 1) to evaluate the extent to which documentation of the medical record is completed for dependent children who present for evaluation of an acute injury, and 2) to examine the factors that favorably or adversely influence completion of the medical record. The emergency department (ED) ledgers of 669 children less than nine years of age were reviewed, including 172 (25.7%) who presented for evaluation of an acute injury. Each of the latter charts was examined for basic demographic data, as well as information about injury type and mechanism, ED provider, and involvement of social services personnel. The ledgers were further examined to determine completeness of chart documentation in several relevant areas, including the circumstances and characteristics of the acute injury, pertinent past medical history, and course of management and referral while in the ED. Each of 15 individual documentation variables was assigned a score of either zero (incompletely/not addressed or documented) or one (completely addressed or documented). The 15 individual scores were equally weighted and summed, resulting in a total documentation score ranging from zero (failure to address or document any of the 15 variables) to 15 (all variables completely addressed/documented). The mechanisms of injury included falls from height (48.3%), direct blunt impact other than falls (26.7%), penetrating injury (6.4%), burn (5.2%), and ingestion (8.1%). Seventeen patients (9.9%) were admitted for primarily medical, and one (0.6%) for primarily social, indications; one patient died as a result of his injuries.(ABSTRACT TRUNCATED AT 250 WORDS)

Child↗
PubMed1995

Lack of an effect of nefazodone on the pharmacokinetics and pharmacodynamics of theophylline during concurrent administration in patients with chronic obstructive pulmonary disease.

The effect of nefazodone on the pharmacokinetics and pharmacodynamics of theophylline was evaluated in a multiple-dose, randomized placebo-controlled, double-blind two-period crossover study in 13 patients who were undergoing theophylline therapy for chronic obstructive pulmonary disease. Two treatments were administered, each for 7 days: theophylline + 200 mg nefazodone twice daily (every 12h) and theophylline+matching nefazodone placebo capsule twice daily (every 12h). Mean peak and trough plasma concentrations of theophylline ranged from 13.1 to 14.5 micrograms ml-1 and 11.6 to 14.2 micrograms ml-1, respectively, at steady-state when theophylline was administered with or without concurrent dosing of nefazodone. Similarly, the mean area under the curve for theophylline ranged from 93.5 to 103 micrograms ml-1 h. When nefazodone and theophylline were co-administered, theophylline pharmacokinetic parameters did not significantly differ from those obtained when theophylline was administered with placebo. Forced expiratory volume in one second (FEV1) measurements taken when nefazodone or placebo were administered with theophylline did not differ from those obtained at baseline. The plasma concentration-time profiles for nefazodone and its metabolites were similar to those in other studies where nefazodone was administered alone. Since nefazodone did not affect the pharmacokinetics or the pharmacodynamics of theophylline, no change in theophylline dose should be needed as a consequence of nefazodone co-administration.

Antidepressive Agents↗
PubMed1995

Cutaneous scleroderma in association with carcinoid syndrome.

A case of scleroderma in a woman with carcinoid syndrome is described and the similarities between our case and those in the literature are reviewed. The carcinoid tumours were all of midgut origin and liver metastases were present. All subsequently developed fibrotic heart disease and none had clinical features or autoantibodies suggestive of systemic sclerosis. The association between carcinoid syndrome and particular features of scleroderma is likely to be more than fortuitous.

Carcinoid Tumor↗
PubMed1995

A randomized, double-blind comparison of methoxamine and epinephrine in human cardiopulmonary arrest.

The beneficial effect of epinephrine has been attributed to its alpha-adrenergic properties. The present study was designed to compare the effects of epinephrine and methoxamine in witnessed cardiac arrests. Consecutive, witnessed cardiac-arrest victims presenting to the emergency room or from the inpatient population of our institution were enrolled in this study. Patients were randomized to receive either epinephrine (2 mg bolus followed by 2 mg every 4 min) or methoxamine (40 mg bolus followed after 4 min by 40 mg) in a blind design. Patients were followed prospectively for survival and neurologic outcome. A total of 199 patients were randomized into the study, but 54 had to be retrospectively dropped from analysis for failure to comply with the study protocol. Of the 145 patients remaining, 77 received methoxamine (M) and 68 epinephrine (E). There was no difference in rate of successful resuscitation (42% versus 53%, M versus E, respectively), or in neurologic outcome as measured by the Glasgow-Pittsburgh Coma Score (GPCS). This study failed to demonstrate any difference in the rate of initial resuscitation, survival to discharge from the hospital, or neurologic status with methoxamine as opposed to epinephrine in the setting of cardiac arrest.

Adult↗
PubMed1995

Tuberculosis as a primary cause of respiratory failure requiring mechanical ventilation.

Tuberculosis as a primary cause of respiratory failure requiring mechanical ventilation (TBMV) is an uncommon occurrence. Over a 10 yr period in the province of Manitoba, Canada (population 1,091,942 in 1991), 13 patients with TBMV were identified. Non-drug-resistant M. tuberculosis was isolated from each case. The patients fell into two categories: miliary or disseminated tuberculosis (n = 7) and tuberculous pneumonia (n = 6); eight developed ARDS (adult respiratory distress syndrome) and another two probable ARDS. The hospital mortality for TBMV was compared with that for mechanically ventilated nontuberculous pneumonia and ARDS patients. Hospital mortality for patients with TBMV (69%, nine of 13) was significantly worse than hospital mortality for patients with nontuberculous pneumonia requiring mechanical ventilation (36%, 34 of 94; p < 0.025) and similar to the hospital mortality for patients with ARDS of any cause (56%, 15 of 27; p > 0.10). APACHE II scores for all groups of patients were similar. Compared with patients with tuberculous pneumonia, patients with miliary or disseminated tuberculosis were significantly more likely to develop TBMV (18.9 versus 0.8%, p < 0.0001). Despite the availability of effective antituberculous drugs, TBMV is often associated with ARDS and carries a similarly high mortality rate. Among patients with pulmonary tuberculosis, those with miliary or disseminated disease are especially prone to develop TBMV.

APACHE↗
PubMed1995

A mathematical analysis of haemorheologic factors during cardiopulmonary bypass for congenital heart disease.

Rheologic properties of blood are impaired by cardiac surgery using cardiopulmonary bypass. This study was set out to establish a mathematical model in order to assess seven known haemorheologic factors and evaluate their degrees of influence on blood rheology in cardiopulmonary bypass. Sixteen patients undergoing elective congenital cardiac surgery were studied. High shear blood viscosity, low shear blood viscosity, haematocrit, red blood cell filtration rate, red blood cell electrophoresis time, plasma viscosity and fibrinogen were monitored. The method for mathematical calculation was the stepwise regression analysis. The results showed that both high shear and low shear blood viscosity were mainly influenced by haematocrit and plasma viscosity. Red blood cell filterability contributed more than red blood cell electrophoresis time for low shear blood viscosity. The mathematical model was re-tested statistically and demonstrated that the selected factors in the model represented approximately 75% of rheologic changes during the surgery. Therefore, this mathematical analysis can be used to estimate the role of various possible haemorheologic factors and evaluate cardiopulmonary bypass techniques and therapeutic interventions.

Adolescent↗
PubMed1995

Prevalence of and risk factors for Chlamydia in a rural pregnant population.

BACKGROUND: Chlamydia trachomatis infection is the most common sexually transmitted bacterial disease in the United States. Perinatal infection with C trachomatis has been associated with preterm labor, preterm rupture of membranes, stillbirth, and both conjunctivitis and pneumonia in newborns. Little is known about the prevalence of C trachomatis infection in rural pregnant women. METHODS: We completed a retrospective chart analysis of 347 obstetric patients in a rural family practice residency training program to determine the prevalence, associated risk factors, and screening criteria for cervical C trachomatis infection. RESULTS: The prevalence of C trachomatis infection in our study was 9.0%. Factors predictive of a positive test for C trachomatis infection included single marital status, African-American race, history of sexually transmitted diseases, presence of gonorrhea during the current pregnancy, age less than 20 years, and late onset of prenatal care. CONCLUSIONS: The prevalence of C trachomatis in this rural obstetric population emphasizes the importance of laboratory screening of rural pregnant women for this disease.

Adolescent↗
PubMed1995

Routine omentectomy is not required in children undergoing chronic peritoneal dialysis.

A routine omentectomy is recommended in children commencing chronic peritoneal dialysis, but is not routine practice in adults. We reviewed the outcome of 66 catheters (57 straight and 9 spiral) inserted into 38 patients (median age 7.8 years, 12 patients under 2 years) over a period of 4.8 years. The aim of the study was to determine whether an omentectomy affects the incidence of catheter blockage or peritonitis. Mean catheter life was 6.8 months (range 0.2-28 months). Fifteen are still in situ, and 14 were removed electively (transplantation). Blockage occurred in 1/22 catheters inserted after an omentectomy, compared with 10/44 inserted without an omentectomy (absolute risk reduction with omentectomy = 0.18). Blockage was more frequent with spiral catheters (4/9 vs 7/57; p < 0.05). Thirty-seven catheters were associated with one or more episodes of peritonitis. Peritonitis was not significantly more frequent after omentectomy. We conclude that a routine omentectomy is not routinely indicated in children commencing chronic peritoneal dialysis. Eleven omentectomies are required to prevent two omental blockages (1/0.18), and secondary omentectomy after blockage is a straightforward procedure. Spiral catheters conferred no benefit in this study. Omentectomy does not influence the incidence of peritonitis.

Adolescent↗
PubMed1995

Kinship support and maternal and adolescent well-being in economically disadvantaged African-American families.

This study tested a conceptual model developed to explain the link between kinship support and the psychological well-being of economically disadvantaged African-American adolescents. The relation of kinship support with maternal and adolescent well-being and mothers' child-rearing practices was assessed in 51 African-American families whose incomes placed them at or below the poverty threshold. Findings revealed that kinship social support to mothers/female guardians was positively associated with adolescent psychological well-being, maternal well-being, and more adequate maternal parenting practices (acceptance, firm control and monitoring of behavior, autonomy granting). Maternal well-being and more adequate maternal parenting practices were positively related to adolescent well-being. Evidence of the mediational role of maternal well-being and parenting practices was revealed. When the effects of maternal well-being and maternal parenting practices were controlled, significant relations between kinship support and adolescent well-being were no longer apparent.

Adaptation, Psychological↗