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Biomedical subjects

D Stevens

Publications and source records attributed to D Stevens.

At least 55 records · Page 3Linked to original sources
PubMed1996

Factors predicting successful labor induction.

OBJECTIVE: To evaluate maternal parity, the sonographic measurement of cervical length, and the five components of the Bishop score to determine which factors best predict the length of latent-phase labor in women undergoing labor induction. METHODS: Cervical position, cervical consistency, cervical effacement, cervical dilation, station of fetal presenting part, maternal parity, and sonographic measurement of cervical length were studied prospectively in 109 women undergoing labor induction. A multiple regression model was used to determine which factors best predict the length of latent-phase labor. RESULTS: A model using these seven factors was predictive in determining the number of hours of latent-phase labor (F = 32.1, P < .001). Backward stepwise multiple linear regression indicated that only cervical dilation independently predicted the length of latent-phase labor. There was a significant correlation between the clinical assessment of cervical effacement and the sonographic estimation of cervical length, (r = -0.523, P < .001). CONCLUSION: Only cervical dilation appears to predict the length of latent-phase labor. The sonographic evaluation of cervical length and maternal parity do not add significant independent information.

Cervix Uteri↗
PubMed1996

High-dose etoposide, cyclophosphamide and total body irradiation with allogeneic bone marrow transplantation for resistant acute myeloid leukemia: a study by the North American Marrow Transplant Group.

We evaluated the toxicity and efficacy of high-dose etoposide, cyclophosphamide and total body irradiation (TBI) followed by allogeneic bone marrow transplantation (BMT) for patients with resistant, acute myeloid leukemia (AML). Between 9/84 and 11/92 we treated 70 patients with etoposide (900-1800 mg/m2), cyclophosphamide (120-180 mg/kg) and TBI (1000-1200 cGy) followed by allogeneic BMT from histocompatible siblings. Forty patients were in untreated first relapse. Median time from diagnosis to transplant was 10 months. Toxicity was similar to that observed with cyclophosphamide/TBI with the median duration of neutropenia (ANC < 500/microliters) being 19 days (range 10-27) and the median duration of thrombocytopenia being 23 days (range 13-173). Twenty-three patients remain in continuous complete remission at a median of 56 months after transplant (range 36-132 months). Probabilities of disease-free survival, persistent/recurrent disease and transplant related mortality are .32, .47, and .37 respectively. Multivariate analysis indicated that grade > or = 2 acute graft-vs-host disease and transplant in untreated first relapse were associated with increased DFS due to reduced relapse risk. We conclude that high-dose etoposide with cyclophosphamide and TBI followed by allogeneic BMT is effective therapy for resistant AML, producing durable remission in approximately one-third of those treated. Disease persistence or recurrence was the major cause of treatment failure. Further improvement in DFS following allogeneic BMT for resistant AML might be achieved by using less intensive GVHD prophylaxis or through infusion of donor peripheral blood cells in patients who fail to develop significant acute GVHD.

Acute Disease↗
PubMed1996

The severity of alpha-particle-induced DNA damage is revealed by exposure to cell-free extracts.

The rejoining of single-strand breaks induced by alpha-particle and gamma irradiation in plasmid DNA under two scavenging conditions has been compared. At the two scavenger capacities used of 1.5 x 10(7) and 3 x 10(6) s-1 using Tris-HCl as the scavenger, the ratio of single- to double-strand breaks for alpha particles is fivefold less than the corresponding ratios for gamma irradiation. The repair of such radiation-induced single-strand breaks has been examined using a cell-free system derived from human whole-cell extracts. We show that the rejoining of single-strand breaks for both alpha-particle- and gamma-irradiated plasmid is dependent upon the scavenging capacity and that the efficiency of rejoining of alpha-particle-induced single-strand breaks is significantly less than that observed for gamma-ray-induced breaks. In addition, for DNA that had been irradiated under conditions that mimic the cellular environment with respect to the radical scavenging capacity, 50% of alpha-particle-induced single-strand breaks are converted to double-strand breaks, in contrast with only approximately 12% conversion of gamma-ray-induced single-strand breaks, indicating that the initial damage caused by alpha particles is more severe. These studies provide experimental evidence for increased clustering of damage which may have important implications for the induction of cancer by low-level alpha-particle sources such as domestic radon.

Alpha Particles↗
PubMed1995

Identification of 4-(N,N-dipropylamino)benzaldehyde as a potent, reversible inhibitor of mouse and human class I aldehyde dehydrogenase.

As the physiologic roles for the different classes of aldehyde dehydrogenase (ALDH) enzymes are elucidated, the identification of specific, reversible inhibitors becomes of great pharmacologic interest. Previous structure-function studies identified dialkylamino substituted benzaldehyde compounds as a novel class of reversible inhibitors of class I ALDH. To examine further structural requirements for inhibition, we tested a series of 4-(N,N-dialkylamino)benzaldehyde analogs as inhibitors of propanal oxidation by mouse liver and human erythrocyte class I ALDH. 4-(N,N-dipropylamino)benzaldehyde (DPAB) was identified as the most potent, reversible inhibitor of propanal oxidation by class I ALDH in spectrophotometric enzyme assays. In kinetic studies, DPAB showed mixed-type inhibition with respect to the aldehyde substrates propanal, phenylacetaldehyde, benzaldehyde, and aldophosphamide. DPAB exhibited uncompetitive inhibition with respect to the cofactor NAD. Inhibition constants (Ki) for DPAB, estimated from Dixon plots, were 10 nM (propanal) and 77 nM (phenylacetaldehyde) for mouse ALDH and 3 nM (propanal) and 70 nM (phenylacetaldehyde) for human ALDH. These Ki values are 100-fold lower than those reported for class I specific inhibitors. At low (< 1 microM) DPAB concentrations, inhibition of propanal and aldophosphamide oxidation was > 75%, whereas inhibition of benzaldehyde (32%) and phenylacetaldehyde (19%) oxidation was reduced markedly. These results indicate that DPAB exhibits potent, reversible inhibition of mouse and human class I ALDH. The degree of inhibition was highly dependent on the structure of the aldehyde substrate.

Acetaldehyde↗
PubMed1995

High-dose etoposide, cyclophosphamide, and total body irradiation with allogeneic bone marrow transplantation for patients with acute myeloid leukemia in untreated first relapse: a study by the North American Marrow Transplant Group.

Relapse is a major cause of treatment failure following allogeneic bone marrow transplantation (BMT) for acute myeloid leukemia (AML). To reduce the risk of relapse following BMT for patients with hematologic malignancy, our group developed a novel preparative regimen which combines high-dose etoposide with cyclophosphamide and total body irradiation (VPCyTBI). We now report the outcome of therapy with VPCyTBI followed by allogeneic BMT for 40 patients with AML in untreated first relapse. With the exception of increased stomatitis, the toxicity of this regimen was similar to that reported by others for CyTBI. Forty-four months after transplant the actuarial probabilities of disease-free survival (DFS), persistent or recurrent leukemia, and transplant related mortality were .29, .44, and .47 respectively. DFS was improved (P < .01) and risk of persistent or recurrent leukemia reduced (P = .005) among patients with significant (grade > or = 2) acute GVHD. Patients with 30% or more blasts on pre-BMT bone marrow examination were not at increased risk for persistent or recurrent leukemia. We conclude that VPCyTBI with allogeneic BMT is effective therapy for AML in untreated first relapse and that a randomized trial comparing this regimen with CyTBI is warranted.

Actuarial Analysis↗
PubMed1995

Internal carotid artery resection for invasion of malignant tumors.

BACKGROUND: To study the preoperative investigation and outcome of patients who underwent resection of the internal carotid artery for malignant disease. A retrospective analysis using a chart review of these patients was performed, and the results were analyzed. All patients were treated by one of us (U.K.N.) at the University of California-Davis Medical Center, Sacramento. A population of 18 patients who underwent a transcervical, transpetrosal, or petrocavernous resection of the internal carotid artery from 1976 to 1993 was studied. Preoperative study consisted of four-vessel arteriography, balloon test occlusion, electroencephalographic intraoperative monitoring, and, after 1990, single-photon emission computed tomographic scanning. Disease-free interval and neurologic complications were assessed. RESULTS: Two patients were alive and well without disease at 6 and 9 months postoperatively. One patient was alive and well at 12 months, and three have survived more than 2 years without recurrent tumor. Eleven patients died within 1 year of surgery (three postoperatively, six of recurrent disease, and two of unknown causes). One patient died of disease at 14 months. CONCLUSIONS: Internal carotid artery invasion by malignancy portends a poor prognosis. Carotid artery resection can provide reasonable palliation. Early results of skull-base surgery on patients with intrapetrous and petrocavernous carotid artery involvement are encouraging. Balloon test occlusion and single-photon emission computed tomographic scanning provide a valuable assessment of contralateral cerebral blood flow.

Adult↗
PubMed1995

Heterotopic microvascular epiphyseal plate transplantation: a new model using the rabbit metatarsal.

The purpose of this study is to develop a new vascularized epiphyseal plate model in the New Zealand White rabbit using a metatarsal epiphyseal plate having limited longitudinal growth potential. Such a model could be utilized in various experiments aimed at manipulating epiphyseal plate growth. The viability of the harvested live subject grafts was demonstrated with continued epiphyseal uptake during Tc99-MDP radionuclide bone scanning. The currently described models used in epiphyseal transplant research all involve long bone epiphyseal plates with significantly greater growth potential than the new metatarsal model. This new model therefore fills a void in the field by allowing investigators to transplant a growth plate with limited growth potential into any heterotopic site and study the effects of various hormonal and physical influences upon epiphyseal plate growth performance.

Animals↗
PubMed1995

A multicentre study of perinatal mortality in Nepal.

A prospective survey was carried out in two Kathmandu hospitals and two rural districts to establish urban and rural perinatal mortality rates (PNMRs) for these four centres in Nepal and to ascertain the causes of perinatal mortality. All perinatal deaths occurring over a 1-year period in the four centres were included (during which time there was a total of 14,967 births). Cause of death was established by contemporary review of hospital case records or by structured questionnaire ('verbal autopsy') in the rural areas. The PNMRs in the hospitals were 48.0 and 23.7 per thousand total births respectively, whilst those of the rural settings were 96.2 and 42.5 per thousand births. Perinatal asphyxia, low birthweight and infection were the most common causes but many of the deaths were unexplained. The high mortality rates were felt to reflect the difficult circumstances of childbirth in Nepal. It was concluded that a number of interventions would appear appropriate, but that these should be introduced in a scientific manner.

Adult↗
PubMed1995

The effect of iron in formula milk after 6 months of age.

Ninety two normal birthweight infants aged 6 months entered a double blind controlled trial which compared a follow on formula milk with no added iron against the same formula milk containing 1.2 mg of iron per 100 ml. There was no significant difference in the social class or demographic characteristics of the two treatment groups or in the proportion of each group completing the trial. There was no difference between the two groups in the quantity of milk taken but the amounts taken lessened between 6 and 18 months of age. There was no difference between the two groups with respect to mean haemoglobin and median serum ferritin at 6, 9, 12, 15, and 18 months of age. Very few infants developed iron deficiency anaemia in either group but there was a tendency for serum ferritin levels to fall between 6 and 18 months of age in both groups. The results suggest that iron added to follow on milk was not an important source of dietary iron in the infants studied.

Anemia, Iron-Deficiency↗
PubMed1995

Persistent grossly elevated erythrocyte sedimentation rate in elderly people: one year follow-up of morbidity and mortality.

The significance of a very elevated erythrocyte sedimentation rate (ESR) in elderly patients is debated. In a retrospective study, we searched the records of a laboratory providing the sole service to a health district for ESR measurement and identified all non-surgical and non-psychiatric patients over the age of 65 who had had an ESR above 50 mm/h. Diagnoses and mortality in a 1-year follow-up were determined from case notes. Four hundred and nine subjects (median age 75; range 65-99) were identified and data on 401 of these (155 male, 246 female; median ESR 80 mm/h, range 50-148) were adequate for 1 year follow-up. Forty-eight percent had a persistently raised ESR (two values > 50 mm/h separated by at least 14 days; group 1); 39% had a single ESR measurement only (group 2), and 13% had a transiently raised ESR (group 3). The commonest diagnosis in group 1 patients was rheumatological disease (51.8%), followed by infection (31.9%) and non-haematological malignancy (11%). Infection was the commonest diagnosis in groups 2 (47.4%) and 3 (43.7%), followed by non-haematological malignancy (19.9%) in group 2 and rheumatological disease (20.4%) in group 3. In only 1 in 20 cases was no diagnosis apparent at 1 year. The standardised mortality ratio (SMR) of the combined groups 1 and 2 (482; CI: 421-544) was strikingly raised, and even more so if patients with rheumatoid arthritis were excluded (542; CI 458-625). Where there were sufficient numbers of deaths to make SMR estimations valid, a gradient of mortality against the level of the ESR could be observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1995

Measuring disability in juvenile dermatomyositis: validity of the childhood health assessment questionnaire.

OBJECTIVE: Physical disability is perhaps the most important outcome of juvenile dermatomyositis (JDM). No functional assessment tool has been validated for inflammatory myopathies either in children or adults. We studied the measurement properties of the Childhood Health Assessment Questionnaire (CHAQ) in children with JDM. METHODS: We studied 37 patients followed at the JDM clinic and compared the results obtained by the CHAQ to a global disease severity score and quantitative muscle strength testing measured by sphygmomanometry (construct validity). We also measured the reliability of the CHAQ and its responsiveness to clinical change. RESULTS: For the initial measurement of each subject, the correlation between disease severity and CHAQ was high [Spearman's correlation, (rs = 0.71, p < 0.002)]. Disability as measured by the CHAQ was inversely correlated with proximal muscle strength (hip abduction rs = -0.57, p < 0.002; shoulder abduction rs = -0.51, p < 0.01) but, as expected, less so with more distal muscle strength (knee extension rs = -0.40, p = 0.05; grip strength rs = -0.079, p > 0.20). The CHAQ was reliable in subjects who showed no clinical change in muscle strength (intraclass correlation coefficient = 0.87) and responsive to treatment induced clinical change (responsiveness coefficient = 0.90). CONCLUSION: The CHAQ can serve as a valid and sensitive tool in the evaluation of functional outcomes in JDM.

Adolescent↗
PubMed1995

A new glucose-6-phosphate dehydrogenase variant, G6PD Orissa (44 Ala-->Gly), is the major polymorphic variant in tribal populations in India.

Deficiency of glucose-6-phosphate dehydrogenase (G6PD) is usually found at high frequencies in areas of the world where malaria has been endemic. The frequency and genetic basis of G6PD deficiency have been studied in Africa, around the Mediterranean, and in the Far East, but little such information is available about the situation in India. To determine the extent of heterogeneity of G6PD, we have studied several different Indian populations by screening for G6PD deficiency, followed by molecular analysis of deficient alleles. The frequency of G6PD deficiency varies between 3% and 15% in different tribal and urban groups. Remarkably, a previously unreported deficient variant, G6PD Orissa (44 Ala-->Gly), is responsible for most of the G6PD deficiency in tribal Indian populations but is not found in urban populations, where most of the G6PD deficiency is due to the G6PD Mediterranean (188 Ser-->Phe) variant. The KmNADP of G6PD Orissa is fivefold higher than that of the normal enzyme. This may be due to the fact that the alanine residue that is replaced by glycine is part of a putative coenzyme-binding site.

Base Sequence↗
PubMed1994

The management of long bone fractures in the head-injured polytrauma patient.

The polytrauma patient who sustains a significant head injury (head and neck Abbreviated Injury Scale of 3 or greater) will require prolonged and technically demanding operative intervention for musculoskeletal and associated soft tissue trauma. The presence of a head injury may delay the immediate surgical intervention for long bone injuries, which has proven to have major advantages for patient care and well-being. This retrospective review of the Sunnybrook Health Science Centre experience between January 1, 1986, and June 1, 1988, identified 153 polytrauma patients with a significant head injury. Forty-five died from complications unrelated to their long bone injuries or treatment thereof, not surviving long enough to reach the operating room for stabilization of their long bone fractures. The 108 survivors sustained 188 long bone injuries, 63 of which were open fractures. Twenty patients were treated nonoperatively. The 88 patients treated operatively had 12 complications: one peroneal nerve palsy; five cases of sepsis (three in open fractures and all resolving with removal of fixation devices); three malunions; and three cases of delayed union. Sixty-nine patients (78%) were available for long-term follow-up, 64 (93%) making a full recovery. Seven required additional surgery to achieve this goal and another patient awaits an ankle arthrodesis. Examining the head and neck AIS and Injury Severity Score of this group showed that 50 (46%) of these patients were expected to die and 22 (44%) made a full recovery.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Nursing students' knowledge and anxiety about AIDS: an experimental workshop.

The purpose of this quasiexperimental study was to examine the effectiveness of an experiential workshop on nursing students' anxiety and knowledge about AIDS. This study was based on Peplau's interpersonal theory in nursing practice. The sample included 67 senior nursing students and was designed as a three-group pre/post quasiexperiment. All groups received a pretest, posttest, and 6-week follow-up posttest. The experimental intervention was a 6-hour workshop that included anxiety awareness exercises in an experiential format and information about AIDS. Knowledge and anxiety scores were significantly higher for the group that attended the didactic portion of the workshop before the experiential portion. The control group showed no change in knowledge or anxiety. Results indicated that recognition of anxiety through experiential exercises contributed to learning about AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Episodes of care for chest pain: a preliminary report from MIRNET. Michigan Research Network.

BACKGROUND: Although intensively studied in hospital and emergency settings, chest pain has remained largely unstudied in primary care, where it is associated with considerable diagnostic uncertainty and high utilization of medical resources. METHODS: We employed an established primary care research network to prospectively collect detailed information on episodes of care for chest pain. Over a 12-month period, Michigan Research Network (MIRNET) clinicians prospectively collected demographic, clinical, and clinician decision-making information for all patients seen in their offices with the complaint of chest pain. RESULTS: Three hundred ninety-nine complete episodes were collected and used for analysis. Episodes were well distributed among urban, rural, academic, and private sites. The average episode length was 1.53 visits. Musculoskeletal chest pain accounted for 20.4% of all diagnoses, followed by reflux esophagitis (13.4%) and costochondritis (13.1%). Stable angina pectoris was the primary diagnosis in only 10.3% of episodes, unstable angina or possible myocardial infarction in 1.5%. Most of the ancillary services used were directed toward finding or excluding cardiac disease. CONCLUSION: A practice-based network can be used to study episodes of care. Resource use during episodes of chest pain in primary care are directed toward exclusion of cardiac disease, despite the surprisingly low frequency of cardiac diagnoses.

Adult↗
PubMed1993

Investigation of urinary tract infection in childhood.

OBJECTIVES: To determine the number of laboratory confirmed urinary tract infections in children and to ascertain general practitioners' practices and attitudes towards their investigation and management. DESIGN: Prospective one year survey of urine specimens submitted for bacteriological investigation; review of radiology department records; questionnaire survey of general practitioners. SETTING: Gloucester health district. SUBJECTS: 57,432 children aged < 15 and 7143 children aged < 2 registered with a general practice in Gloucester health district and their 195 general practitioners. RESULTS: 4317 urine specimens were submitted from children aged < 15, of which 563 from 442 children were culture positive. The rate (number/100 children/practice) of culture positive urine specimens in these children varied more than 10-fold between general practices, and this correlated closely with the rate of referral of urine specimens for investigation. A follow up specimen to check for clearance of infection was taken in 22% (125/563) of infections. Of the 821 specimens submitted from children aged < 2, 103 from 89 children were positive. Of these children, 28 underwent radiological imaging. Most general practitioners would aim to obtain bacteriological confirmation of urinary tract infection on weekdays but only a minority said they would do so at weekends. They were apparently more likely to refer boys and younger children for renal tract imaging after a first urinary tract infection. CONCLUSIONS: Urinary tract infection in children was underdiagnosed, and after a confirmed infection only a minority of patients received renal tract imaging or microbiological follow up. Greater awareness of the importance of investigation and management of urinary tract infection in children is needed, and the practical difficulties faced by general practitioners must be resolved.

Adolescent↗