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Biomedical subjects

L Howell

Publications and source records attributed to L Howell.

At least 19 recordsLinked to original sources
PubMed2006

Isolated parenchymal lesions on cranial ultrasound in very preterm infants in the context of maternal infection.

AIM: To explore the associations between a clinical diagnosis of maternal infection (CDMI) and findings on the initial cranial ultrasound scan in very preterm infants. METHODS: Among infants born at less than 32 weeks gestation, cases of CDMI and controls were identified on the basis of routinely available obstetric data. Neonatal cranial ultrasound scans carried out soon after birth were retrospectively reviewed for evidence of parenchymal echodensity (PED), intraventricular haemorrhage (IVH) or PED contiguous with IVH. RESULTS: Any PED was identified in 20/40 (50%) cases of CDMI and 9/30 (30%) of controls. Logistic regression was used to adjust for differences between the two study groups. When compared with normal scans, isolated PED was more likely with CDMI odds ratio, OR (95% confidence interval, CI), 41.8 (2.64, 662) and lower Apgar score at 5 min 2.89 (1.05, 7.98). IVH was more likely with lower gestational age, OR for each completed week of gestation 0.64 (0.46, 0.88) and a protective effect of female sex, OR 0.25 (0.063, 0.98), PED contiguous with IVH was more likely with lower gestational age OR 0.59 (0.336, 1.04). CONCLUSIONS: CDMI may be associated with isolated PED in very preterm infants. We speculate that isolated PED (including "flares") identify infants who have sustained early brain injury because of intrauterine infection. Isolated PED may be a useful intermediate outcome in perinatal cohort studies.

Apgar Score↗
PubMed2005

An exploratory comparison of genetic counselling protocols for HNPCC predictive testing.

Most UK genetics centres offering predictive testing for hereditary non-polyposis colorectal cancer (HNPCC) use an extended counselling protocol originally developed for Huntington's disease. Shortened counselling may be more appropriate in the context of treatable genetic conditions such as HNPCC. Twenty-six high-risk individuals were randomized to extended genetic counselling (two sessions of education and reflection held 1 month apart) or shortened genetic counselling (a single educational session) prior to HNPCC testing. Prospective questionnaires, interviews and transcripts of counselling sessions were analysed. Participants were unsure what to expect prior to genetic counselling and had already decided to undergo genetic testing. There was no evidence of psychological harm caused by shortened genetic counselling, with a high level of satisfaction with the counselling received in both groups. Reflective counselling occurred in both groups but was framed in terms of practical action and information. Participants expressed differing preferences for the level of information received. This exploratory study indicates that shortened genetic counselling may be an appropriate means of supporting decisions already made by individuals about HNPCC testing. However, participants would benefit from preparatory information to help them reflect on issues not previously considered, which can then be explored more fully as part of a tailored counselling approach.

Adult↗
PubMed2000

Sorting of the vasopressin prohormone into the regulated secretory pathway.

The sorting of soluble proteins into the regulated secretory pathway (RSP) involves aggregation, but whether an additional sorting domain is also required is not clear. By fusing vasopressin prohormone (proVP) fragments to green fluorescent protein (eGFP) we have determined whether a sorting domain can function independently of the aggregative neurophysin domain. Although eGFP itself can be immunolocalised in the RSP of Neuro2A and AtT20 cells, most of the protein enters the constitutive pathway, and is found in the culture medium. In contrast, the N-terminal 27 residues of proVP promote residence in the RSP. Furthermore, only the processed form of this fusion was secreted when stimulated. We suggest a sorting mechanism based on the recognition of a sorting motif, the efficiency of which is enhanced by neurophysin aggregation.

Animals↗
PubMed2000

Can peak expiratory flow predict airflow obstruction in children with asthma?

STUDY OBJECTIVES: A recent trend in the treatment of asthma has been the widespread, independent use of peak expiratory flow (PEF). We examined whether PEF monitoring creates inaccuracies in assessment of children with moderate to severe asthma. METHODS: We compared the negative predictive value of PEF in relation to the forced expiratory volume in 1 second (FEV(1)), and to the forced expiratory flow between 25% and 75% of the vital capacity (FEF(25-75%)) at different levels of air trapping as determined by the residual volume over total lung capacity ratio (RV/TLC). RESULTS: The study included 244 patients, ages 4 to 18 years with all classes of asthma severity, with FEV(1) ranging from 28% to 134% of predicted value. We analyzed 367 sets of pulmonary function tests performed throughout a 3-year period. Thirty percent of patients with a normal PEF value had an abnormal FEV(1) or FEF(25-75%). As air trapping increased, the ability of a normal PEF to predict normal FEV(1) and FEF(25-75%) readings fell from 83% to 53%. The negative predictive value was significantly lower for patients with RV/TLC ratio >30 compared with patients with RV/TLC <30. CONCLUSIONS: The results of this study suggest that it might be possible to identify children for whom the PEF is likely to give false-negative results. As air trapping increases, it causes the PEF to give misleading reassurance of normal pulmonary function. Furthermore, poor predictiveness of PEF is obtained when values 80% of predicted for age are considered normal.

Adolescent↗
PubMed1999

Lung function in infants with wheezing and gastroesophageal reflux.

Eighty-four otherwise healthy infants with daily wheezing underwent infant pulmonary function tests (IPFTs) and 24-h esophageal pH probe studies. Fifty-four (64%) infants had positive pH probe studies, and 30 infants had negative pH probe studies. Many infants in both groups had evidence of peripheral airflow obstruction at tidal breathing and on forced expiration as measured by thoracoabdominal compression. In infants with gastroesophageal reflux (GER), only 9 of 54 (16.6%) responded to bronchodilator therapy compared to 20 of 30 (66.6%) in the group with negative pH probe studies (P < 0.0005). In infants with positive pH studies, family history of asthma (n = 16) correlated well with positive response to bronchodilators (P < 0.0005), and all infants exposed to maternal smoking (n = 11) had no response to bronchodilators. Forty-four percent of infants with a positive pH probe had no gastrointestinal symptoms suggestive of GER. In infants with a negative pH probe, family history of asthma (n = 24) correlated well with positive response to bronchodilators (P < 0.0005), and exposure to maternal smoking (n = 8) correlated well with no response to bronchodilator therapy (P < 0.0005). We conclude that silent GER is common in infants with persistent wheezing. Furthermore, infants with GER are less likely to respond to bronchodilator therapy, and exposure to maternal smoking and family history of asthma may be significant independent factors.

Asthma↗
PubMed1999

Gastroesophageal reflux in infants with wheezing.

The relation between silent gastroesophageal reflux (GER) and respiratory problems such as persistent wheezing in infants is not well-established. Between January 1994 and June 1997, we evaluated the incidence of GER in 84 otherwise healthy infants referred to the Pediatric Pulmonary Medicine Division at Kosair Children's Hospital for evaluation of daily wheezing, and we followed their clinical course for 18 months. All underwent 24-hr esophageal pH studies to evaluate GER. The pH probe study was performed at a mean age of 8.74 +/- 4.6 months. Infants with a positive GER study were treated with an H2 receptor antagonist (H2RA) and a prokinetic agent for a mean of 5.6 +/- 2.4 months. At first follow-up visit 3 weeks after esophageal pH studies infants treated with an H2RA and those who did not have GER but continued with daily wheezing were started on flunisolide nasal solution (0.025%) delivered by nebulizer (125 mcg t.i.d.). Infants in both groups were followed every 1-2 months for a mean of 18 months and if clinically improved, attempts to decrease their daily asthma medications were made. Fifty-four of 84 (64%) had positive esophageal pH studies (GER-positive group), and 24 of them (44%) had no gastrointestinal symptoms suggestive of GER. Thirty patients had normal esophageal pH studies (GER-negative group). Twenty-two of these 30 (73%) infants without GER required nebulized flunisolide, compared to 13 of 54 (24%) infants with GER (P < 0.0005). Thirty-five of 54 (64.8%) infants with GER were able to discontinue all daily asthma medications within 3 months of starting antireflux therapy, while none of the infants without GER were able to discontinue daily asthma medications during the follow-up period (P < 0.0005). We conclude that silent GER is common in infants with daily wheezing, and controlling GER improves morbidity and decreases the need for daily asthma medications.

Anti-Asthmatic Agents↗
PubMed1999

Comparison of the efficacy of inhaled fluticasone propionate, 880 microg/day, with flunisolide, 1500 microg/day, in moderate-to-severe persistent asthma.

BACKGROUND: Inhaled corticosteroids have become the mainstay of asthma therapy. Few studies however, have compared inhaled steroids in children. We compared the efficacy of inhaled fluticasone propionate (FP), 880 microg/day (2 puffs of 220 microg/puff, BID) with inhaled flunisolide (FLU), 1500 microg/day (3 puffs of 250 microg/puff, BID). METHODS: Thirty children with moderate to severe asthma, mean age 12.7 years (range 10 to 17 years), mean duration of asthma 8.4 years, initially received flunisolide 1500 microg/day for 1 year, and then were switched to fluticasone propionate 880 microg/day and followed for an additional year. Pulmonary function tests (PFTs) were monitored and analyzed before and after the switch for the duration of study. Mean percent predicted for age values for FVC, FEV1, FEF25-75%, and FEFR were compared at 1 month, 2 to 6-month intervals, and 7 to 12-month intervals and during the same season of the year. Pulmonary function tests within 3 weeks of an exacerbation were not included in the study. The number of asthma exacerbations, emergency room visits, hospital admissions, and number of school days lost were also compared. RESULTS: There was significant improvement in mean asthma exacerbations/patient/year (1.7 +/- 1.66 SD) versus (4 +/- 2.6) (P < .0002); mean emergency room visits/patient/year (0.23 +/- 0.62) versus (1.2 +/- 1.74) (P = .004); mean hospital admissions for asthma/patient/year (0.2 +/- 0.61) versus (1.13 +/- 1.45) (P < .0002); and number of school days lost/patient/year (1.4 +/- 2.38) versus (7.93 +/- 6.7) (P < .0002) while patients were receiving fluticasone propionate as compared with flunisolide. Also, the mean percent values predicted for age in all time-periods (at 1 month, 2 to 6 months, and 7 to 12 months) revealed significant improvement in FEV1 and FEF25-75% (P < .05 for both parameters). As PFT can be affected by seasonal changes, PFT parameters were compared during the same season of the year and significant improvement in FVC and FEV1 was observed in all seasons while patients were receiving fluticasone propionate (FP) compared with flunisolide (FLU) (P < .05 for all parameters). Significant improvement in PEFR and FEF25-75% was observed only in spring and summer season. CONCLUSION: Fluticasone propionate 880 microg/day improved lung function and quality of life in adolescents with moderate-to-severe asthma when compared with flunisolide 1500 microg/day.

Absenteeism↗
PubMed1999

Comparison of lung function in infants exposed to maternal smoking and in infants with a family history of asthma.

STUDY OBJECTIVE: To compare lung function in infants exposed to maternal smoking with lung function in infants with a family history of asthma. There are no published studies comparing lung function in both groups. DESIGN: Cross-sectional study. SETTING: A tertiary pulmonary care center at a children's hospital. PATIENTS: One hundred five infants with daily wheezing. Thirty-five infants had persistent exposure to maternal smoking, and 70 had a family history of asthma in parents or siblings. MEASUREMENTS: Infant pulmonary function tests were compared between the two groups. The ratio of terminal to peak expiratory flow at tidal breathing at 25% of the previous expiration remaining and the ratio of terminal to peak expiratory flow with forced expiration at 25% of the previous expiration remaining (FEF25/PFEF) were used to evaluate peripheral airflow. A > 25% improvement in FEF25/PFEF after a bronchodilator challenge test was considered a positive response. RESULTS: Most infants in both groups had evidence of peripheral airflow obstruction with forced expiration. In infants exposed to maternal smoking, only 4 of 35 (11.4%) responded to a bronchodilator, compared to 51 of 70 (72.9%) in the group with a family history of asthma (p < 0.0005). There was no statistically significant difference in total respiratory system compliance, total respiratory system resistance, tidal volume, and degree of peripheral airflow obstruction at tidal breathing or after forced expiration in both groups. CONCLUSION: Infants with exposure to maternal smoking and infants with a family history of asthma have altered lung function, and a positive response to a bronchodilator is one variable that seems to differentiate the two groups.

Airway Resistance↗
PubMed1999

Severe migratory granulomatous reactions to silicone gel in 3 patients.

In humans implanted with silicone gel breast prostheses, a mild foreign body response results in the formation of a collagenous capsule around the prosthesis. Although many such patients may show evidence of a microscopic granulomatous foreign body reaction upon examination of capsular material at explantation of a prosthesis, it is unusual to have large, palpable granulomas, even in the presence of rupture or leakage. Rare patients have had severe local inflammation and complications resulting from silicone migration to the axilla, arm, or abdominal wall. We describe 3 patients who had deforming granulomas after implant rupture, along with other consequences of silicone gel migrating down the upper extremity. Silicone gel, once it leaves the implant, is not biologically inert and in some persons can elicit profound pathologic responses.

Adult↗
PubMed1998

Ultrasound and MR imaging of fibromatosis colli (sternomastoid tumor of infancy).

The sonographic and CT findings of fibromatosis colli (sternomastoid tumor of infancy) have been described, but the MRI appearance has been reported in only one case in which the mass resolved over time. This case describes the detailed MRI findings in a biopsy-proven case of fibromatosis colli; the signal intensity of the mass on T2-weighted images was slightly less than on gradient-recalled T1-weighted images, consistent with the presence of some fibrous tissue within the muscle mass. The involved portion of the muscle was better defined on MRI than sonography. MRI was helpful in demonstrating the signal characteristics of the mass; localizing the mass to within the sternocleidomastoid muscle; and demonstrating clear surrounding fascial planes with lack of associated lymphadenopathy, airway compression, vascular encasement, bone involvement or intracranial/intraspinal extension associated with other neck masses.

Biopsy, Needle↗
PubMed1997

Detection of high-grade cervical dysplasia: impact of age and Bethesda system terminology.

Pap smear, colposcopy, and biopsy results were collected from 1988-1993 at a group of family planning clinics. Positive predictive values and likelihood ratios were calculated for diagnosis of high-grade lesions based on age and Pap smear results. One thousand and forty-seven colposcopies were logged; 771 had a biopsy or endocervical curettage. Seventy-nine (10%) were high-grade lesions. If only human papillomavirus (HPV) was reported on the Pap smear, the likelihood of a high-grade biopsy was lowest (positive predictive value, 4.5%; likelihood ratio, 0.4). Women under age 25 were less likely to have high-grade biopsies (positive predictive value, 7.3%; likelihood ratio 0.7). Repeat Pap smears for atypical cells of undetermined significance (ASCUS) and low grade squamous intra-epithelial lesion (LGSIL) showing only HPV in women under age 30 would have reduced the immediate colposcopy rate by 60% and delayed diagnosis by 23% of high-grade lesions. Consideration of patient age and whether HPV is the only Pap smear finding may reduce referral for immediate colposcopy.

Adult↗
PubMed1995

Annual changes in serum concentrations of prolactin in captive male black bears (Ursus americanus).

Prolactin may be involved in the regulation of reproduction in black bears (Ursus americanus) as it is a mediator of photoperiodic changes in a number of species. The objectives of this study were to validate a radioimmunoassay to measure prolactin in bear serum and to describe seasonal changes in serum prolactin concentrations in captive male bears. Serum samples were obtained nine times during a year from three captive male black bears that were denning between November and March and active during the other months. The heterologous prolactin radioimmunoassay, using pig 125I-labelled prolactin and goat anti-pig prolactin as a primary antibody, was validated. Injection of thyrotrophin-releasing hormone into the three male bears in June resulted in a rapid increase in serum concentrations of prolactin (t = 0, 11.4-14.8 ng ml-1; t = 15-30 min, 18.4-28.7 ng ml-1). The sensitivity of the assay was 0.08 ng per tube. Intra- and interassay coefficients of variation were 5.5% (n = 6) and 5.7% (n = 6), respectively. Serum concentrations of prolactin changed seasonally, with the lowest concentrations in December (mean +/- SD = 1.1 +/- 0.1 ng ml-1); this was followed by a gradual increase between January (2.6 +/- 0.6 ng ml-1) and April (6.4 +/- 1.2 ng ml-1) and the highest concentrations in May (17.6 +/- 4.7 ng ml-1), preceding peak testosterone concentrations in June. The observation that prolactin secretion increased with increasing daylength suggests that photoperiod may be an external regulator. The presence of high concentrations of prolactin before peak testosterone concentrations suggests that prolactin may play a role in regulating seasonal changes in the testes.

Animals↗
PubMed1993

Sound learning--shared multi-site learning through audiobridge.

Amalgamation of nurse education centres in the UK has resulted in the formation of large, multi-site institutions with a number of campuses situated some distance away from the main centre. Pre-Registration Courses run by the college often have most theoretical elements of the course based in the main centre, with students travelling from satellite centres to attend. Post-Registration Education and Practice Project legislation and the need for all qualified staff to have access to facilitators of education may prove more difficult for those practising in remote areas. An audiobridge has been established, linking education sites in Portsmouth, the Isle of Wight and Guernsey. The Guernsey centre was first 'on-line' and has piloted the use of the bridge. Insights have been gained into the values and limitations of the system which may prove useful to others. Strategies for accessing and using the bridge, the preparation of learning experiences to be undertaken over the bridge and the actual practicalities of using the equipment to deliver and participate in lessons where sound is the main sense to be utilised, have all been addressed to deliver lectures, tutorials, seminars and meetings. Student-centred learning and direct student access for peer support networks are anticipated.

Education, Nursing, Baccalaureate↗
PubMed1991

Effect of a bulk-forming cathartic on diarrhea in tube-fed patients.

Diarrhea is a significant complication for the patient being tube-fed. The purpose of this study was to observe whether giving a bulk-forming cathartic to patients receiving enteral nutrition via nasogastric or nasoduodenal tube would result in firmer stools for these patients. Forty-nine patients in a large medical center were randomly assigned to either a control or an experimental group. During the 6-day study period 1 teaspoon (5 ml) of psyllium preparation was administered through the feeding tube three times a day. Data were analyzed by using the Mann-Whitney U test for nonparametric data. The hypothesis that giving a bulk-forming cathartic would lead to firmer stools was supported at an alpha level of less than 0.01. The results of this study suggest that use of a bulk-forming cathartic in tube-fed patients will significantly reduce the diarrhea associated with this type of feeding.

Administration, Oral↗
PubMed1990

A clinically applicable method to preserve urine and bladder washing cells for flow cytometric monitoring of bladder cancer patients.

We describe a method to fix exfoliated bladder cells that is suitable for followup of bladder cancer patients by deoxyribonucleic acid flow cytometry. After fixation with room temperature methanol plus acetic acid (20:1, volume:volume) urine and bladder washing samples from these patients can be stored at room temperature for 3 to 7 days and then assessed reliably for the presence of aneuploidy and the percentage of hyperdiploid cells. For those with active transitional cell carcinoma diagnostic accuracy comparing fresh to fixed specimens was improved from 58 to 92% with urine and from 50 to 100% with washing samples. For patients with a history of transitional cell carcinoma who currently are free of disease the false positive rate remains unchanged after fixation. The procedure described is suitable for use in the outpatient clinic and should permit shipping of samples without refrigeration to a central flow cytometry facility for analysis.

Carcinoma, Transitional Cell↗
PubMed1989

Do electrode and lead design differences for permanent cardiac pacing translate into clinically demonstrable differences? (Comparison of sintered platinum and activated vitreous and porous carbon electrodes).

A randomized prospective study was undertaken to compare the electrical performances of three permanent, endocardial, tined pacing leads with different electrode designs--sintered platinum, vitreous carbon, and porous carbon. Ninety-nine patients received one of the leads (S80 31; 423S 32; S100 36). Acute R wave amplitude and ST elevation of the native endocardial electrogram, voltage threshold, impedance, and current flow at four pulse durations (0.25-1.0 msec) were measured. Voltage thresholds were measured noninvasively at each of four pulse durations at 2 days and 1, 3, and 6 months after implantation. No significant differences were found in sensing properties, or current flow at threshold at 0.5 msec pulse duration. The 423S lead had a significantly higher impedance at threshold and both a higher impedance and lower current flow at 5 V. No significant differences in threshold voltages were found between the three leads at any pulse duration, at any of the assessed times after implantation. Six-month thresholds for the S80, 423S, and S100 leads were 1.18 +/- 0.35, 1.17 +/- 0.29, and 1.06 +/- 0.38 V respectively at 0.5 msec pulse duration. Differences between 'high performance' pacing leads need to be of a greater order of magnitude before they can be exploited to give any real clinical advantage to patients.

Aged↗
PubMed1989

G syndrome and its otolaryngologic manifestations.

G syndrome is a familial constellation of congenital anomalies that include a distinctive facies, ocular hypertelorism, prominent occiput and forehead, short lingual frenulum, stridor, hoarse cry, and laryngotracheoesophageal (LTE) clefts, as well as hypospadias and cryptorchidism. Approximately one third of the reported cases have also involved cleft lip and/or palate. Thirty cases of this syndrome have been reported in the pediatric and genetic literature, with variable expression of the syndrome characteristics. The purpose of this article is to report two additional cases of G syndrome with LTE cleft. A technique for repair of LTE cleft via a lateral pharyngeal approach is described. Although G syndrome is rare, otolaryngologists should be aware of its association with LTE cleft and its potential life-threatening problems.

Abnormalities, Multiple↗