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Biomedical subjects

S Hogan

Publications and source records attributed to S Hogan.

At least 19 recordsLinked to original sources
PubMed2001

Management and long-term follow-up of hepatic cysts.

PURPOSE: To provide an algorithm for the management of hepatic cysts through an analysis of our series over 16 years. METHOD: We reviewed the surgical management and outcome of patients with hepatic cysts between 1984 and 2000 at a single institution. Data were collected by chart review, telephone interview, and follow-up hepatic ultrasonography. RESULTS: Forty-four patients (36 females, 8 males) underwent a total of 46 operations for hepatic cysts (mean size 12.0 +/- 5.2 cm) with a mean follow-up of 5.1 +/- 4.0 years. We treated 28 simple cysts, 4 polycystic liver disease (PCLD), 7 cystadenomas, 2 hydatid cysts, 1 cystadenocarcinoma, 1 endometrioma, and 1 hepatic foregut cyst. Operations included simple drainage, wide unroofing (open and laparoscopic), and hepatic resection. Four patients experienced a symptomatic recurrence after definitive treatment; 3 of these patients had PCLD. Four of the 7 patients with cystadenomas had undergone previous operations that required subsequent definitive resection without a recurrence. CONCLUSIONS: The preoperative distinction between simple cysts and cystadenomas/cystadenocarcinomas can be difficult, yet the management is different. Unroofing is a safe and effective operation for patients with simple cysts. Patients with PCLD frequently have recurrences. Cystadenomas should be completely resected owing to the likelihood of recurrence after partial excision and the risk of eventual cystadenocarcinoma. We present a treatment algorithm for the preoperative evaluation and management of hepatic cysts based on the largest number of patients with the longest follow-up reported to date.

Adolescent↗
PubMed2000

Maximum urine concentrating ability in children with Hb SC disease: effects of hydroxyurea.

Studies in adults with Hb SC disease suggested that hydroxyurea reduced hemolysis and increased red cell hydration. Because increased hydration should diminish the polymerization tendency of Hb S we hypothesized that hydroxyurea might repair the urine concentration defect of HbSC disease. Eight Hb SC disease patients, aged 10 to 17 years, were given hydroxyurea daily. Maximal urine concentrating ability following overnight fasting and after subcutaneous arginine vasopressin (dDAVP), blood counts, and cell volumes were observed for 12-15 months. All patients had impaired urine concentrating ability prior to hydroxyurea treatment and failed to increase their ability to concentrate urine following treatment (maximum urine concentration after an overnight fast and dDAVP, 520-530 mOsm). Mean corpuscular volume (MCV) and reticulocyte MCV increased after administration of hydroxyurea, and the reticulocyte count and ratio of red cell hemoglobin to reticulocyte hemoglobin fell but there was little change in PCV. Hb F increased substantially in 2 patients but showed little change in the remaining patients. There was no evidence that hydroxyurea was associated with increased urine concentrating ability in children with Hb SC disease. These results may reflect irreversible renal medullary damage prior to beginning treatment or insufficient intensity or duration of treatment.

Adolescent↗
PubMed2000

Purified herpes simplex thymidine kinase retroviral particles. II. Influence of clinical parameters and bystander killing mechanisms.

High-titer, purified herpes simplex virus thymidine kinase (HSV-TK) retroviral particles, followed with intraperitoneal ganciclovir (GCV) were tested in Fischer rats bearing 1-week established 9L gliosarcomas. 9L cells were infused intracranially through a cannula on day 0, given intracranial infusions of HSV-TK retroviral particles on days 7-12, and given 5 or 10 daily doses of intraperitoneal GCV starting at day 14. Tumor volumetric studies performed on rat brains at day 26 after tumor infusion revealed significant differences in experimental groups receiving HSV-TK retroviral particles plus 10-day GCV or the 100% transduced 9L-TK group receiving GCV versus control groups treated with either buffer, HSV-TK vector, or either 5- or 10-day regimens of GCV alone. The duration of GCV administration and the volume of tumor burden influenced efficacy. Adjuvant dexamethasone did not significantly affect efficacy. Experiments in which 9L rechallenge of animals treated with 9L-TK/GCV or 9L tumors treated with HSV-TK vector/GCV indicated that a host immune response was involved in rejecting the rechallenge tumor. Outcome was dependent upon the site and size of the rechallenge inoculum. In vitro, bystander effects were significant but were especially marked when cell-to-cell contact was maintained. Cumulatively, the data indicate that both the bystander effect and the host immune response are responsible for the efficacy observed in the suicide gene therapy paradigm using purified HSV-TK retroviral particles and GCV to treat smaller tumor burden in rats with 9L gliosarcoma.

Animals↗
PubMed1998

Industrial platforms--a unique feature of the European Commission's biotechnology R&D programme.

The European Commission's research, technological development and demonstration programmes aim to strengthen European research and technological development, and to increase the competitiveness of European industries. The creation and development of Industrial Platforms play an important role in these processes by improving the transition from research to commercial application. Industrial Platforms are technology-based industrial groupings established by industry with the aims of enabling the exploitation or dissemination of research results, encouraging academic-industrial collaborations and providing their members with a means of voicing their opinion on present and future research policies.

Biotechnology↗
PubMed1997

Cyclophosphamide therapy for lupus nephritis: poor renal survival in black Americans. Glomerular Disease Collaborative Network.

Intravenous cyclophosphamide is widely used to treat severe lupus nephritis. Yet interpretation of the literature is limited by the small number of patients evaluated with varied renal histology. We analyzed the renal outcome of cyclophosphamide therapy for diffuse proliferative lupus glomerulonephritis in a cohort of 89 patients from the Glomerular Disease Collaborative Network. Statistical analysis included Wilcoxon rank sum tests or continuity-adjusted chi-square for comparisons between groups. Kaplan-Meier survival function estimates were calculated for renal survival curves. Cox's proportional hazards models were employed for multivariate evaluation. The renal survival rate declined yearly from 89%, to 86%, 81%, 75%, and 71% at year 5. Renal survival was significantly worse in blacks compared with white patients. Among white patients 95% retained renal function at year 5 whereas black patients showed a progressive yearly decline from 85% at year 1, to 79%, 72%, 62%, and 58% at year 5. Racial differences in renal outcome were independent of age, duration of lupus, history of hypertension, hypertension control during therapy, and activity or chronicity indices on renal biopsy. The factors that predispose black patients to more aggressive and treatment-resistant lupus nephritis are not apparent.

Adolescent↗
PubMed1994

Screening for hearing loss in an at-risk neonatal population using evoked otoacoustic emissions.

The present study examines the performance of a transient evoked otoacoustic emissions hearing screening programme for neonates with risk factors for hearing loss. The programme has run for 5 years, and 772 babies with various risk factors have been screened using the Programmable Otoacoustic Emissions Measurement System (POEMS) designed by the Medical Research Council Institute of Hearing Research. Fourteen cases of significant hearing loss have been detected, with no false negative results. However, a very high false positive rate is reported, especially in babies with a birthweight of less than 1500 g.

Cochlea↗
PubMed1992

Isolation and characterization of genetic expression and secretion signals from Enterococcus faecalis through the use of broad-host-range alpha-amylase probe vectors.

We have constructed two broad-host-range Gram+/Gram- probe vectors designed for the cloning of bacterial genetic expression and secretion signals. These vectors make use of a silent reporter gene encoding the mature alpha-amylase from Bacillus licheniformis whose reactivation can easily be monitored on iodine-stained starch plates. Shotgun cloning of Enterococcus faecalis DNA fragments allowed recovery of several cassettes directing transcription, translation of the reporter gene and secretion of alpha-amylase. Sequence analysis revealed, in each case, the presence of a putative promoter, ribosome-binding site and signal peptide similar to those described in other Gram+ bacteria.

Amino Acid Sequence↗
PubMed1991

Primary structure and processing of the Candida tsukubaensis alpha-glucosidase. Homology with the rabbit intestinal sucrase-isomaltase complex and human lysosomal alpha-glucosidase.

The nucleotide sequence of a 4.39-kb DNA fragment encoding the alpha-glucosidase gene of Candida tsukubaensis is reported. The cloned gene contains a major open reading frame (ORF 1) which encodes the alpha-glucosidase as a single precursor polypeptide of 1070 amino acids with a predicted molecular mass of 119 kDa. N-terminal amino acid sequence analysis of the individual subunits of the purified enzyme, expressed in the recombinant host Saccharomyces cerevisiae, confirmed that the alpha-glucosidase precursor is proteolytically processed by removal of an N-terminal signal peptide to yield the two peptide subunits 1 and 2, of molecular masses 63-65 kDa and 50-52 kDa, respectively. Both subunits are secreted by the heterologous host S. cerevisiae in a glycosylated form. Coincident with its efficient expression in the heterologous host, the C. tsukubaensis alpha-glucosidase gene contains many of the canonical features of highly expressed S. cerevisiae genes. There is considerable sequence similarity between C. tsukubaensis alpha-glucosidase, the rabbit sucrase-isomaltase complex (proSI) and human lysosomal acid alpha-glucosidase. The cloned DNA fragment from C. tsukubaensis contains a second open reading frame (ORF 2) which has the capacity to encode a polypeptide of 170 amino acids. The function and identity of the polypeptide encoded by ORF 2 is not known.

Amino Acid Sequence↗
PubMed1991

Reduction of atherogenic risk factors by short-term weight reduction. Evidence of the efficacy of National Cholesterol Education Program guidelines for the obese.

Five hundred and ninety-nine overweight patients participated for at least 4 weeks in the weight reducing and physical activity promoting Diet and Fitness Center program at Duke University. Twenty-three percent were diabetic and 49% hypertensive. With only modest weight loss (11.8 kg in males and 8.2 kg in females) abnormal levels of blood pressure, fasting blood sugar, total cholesterol, LDL-cholesterol and triglycerides normalized. It was very rewarding to see these results achieved in a very limited period of time. Improvements in the lipid profile were consistent with the predicted outcome of obesity treatment stated by the National Cholesterol Education Program guidelines.

Adult↗
PubMed1991

Acceptability of binaural hearing aids: a cross-over study.

Using screening questionnaires we were able to detect individuals aged 50-65 years with hearing disability in a general practice population. Those who had better ear hearing levels of 30 dB or worse were invited to take place in a cross-over study comparing the acceptability of a monaural or binaural hearing-aid fitting. Fifty-five per cent ultimately opted for a binaural fitting and had greater hearing disability and worse mean hearing levels than those who opted for a monaural fitting. They made their choice for acoustical reasons, particularly on the basis of improved localization ability.

Audiometry↗
PubMed1991

The desynchrony between complaints and signs of vestibular disorders.

As part of an early intervention study on the acceptability of auditory rehabilitative intervention, we examined patient complaints and clinical findings of balance disorders. Hallam et al. have discussed desynchrony between such findings in hospital patient populations, and the aim of the present study was to investigate these relationships in a general population. The study was conducted in two industrial villages in Wales in which questionnaires were circulated to all individuals in the 50-65 age group. A marked desynchrony between semeions and clinical findings was found. This has been related to the desynchrony between auditory impairment, disability and handicap in this population. Subjects reporting giddiness or vertigo were more disabled but not more impaired in respect of auditory measures than those not reporting such balance problems. Those with abnormal balance test results showed no auditory differences from those with normal results.

Aged↗
PubMed1990

Clinical course of anti-neutrophil cytoplasmic autoantibody-associated glomerulonephritis and systemic vasculitis. The Glomerular Disease Collaborative Network.

OBJECTIVES: To determine the spectrum of clinical manifestations in patients with anti-neutrophil cytoplasmic autoantibody (ANCA)-associated glomerulonephritis; to determine renal and patient survival in these patients; to compare survival among patients treated with corticosteroids alone, corticosteroids plus intravenous cyclophosphamide or corticosteroids plus oral cyclophosphamide; and to assess the correlation of disease manifestations and treatment response with ANCA subtypes and serial autoantibody titers. DESIGN: Inception cohort study; mean follow-up of 24 months. SETTING: Collaborative network of 120 university and private practice nephrologists (The Glomerular Disease Collaborative Network). PARTICIPANTS: Seventy patients with ANCA and pauci-immune necrotizing and crescentic glomerulonephritis, of whom 59 were treated with either corticosteroids alone (14 patients), corticosteroids plus oral cyclophosphamide (30 patients), or corticosteroids plus intravenous cyclophosphamide (15 patients). MAIN RESULTS: Of the 70 patients, 18 had renal-limited disease (idiopathic crescentic glomerulonephritis); 15, nonpulmonary extrarenal disease consistent with polyarteritis nodosa; and 37, pulmonary disease consistent with Wegener granulomatosis or alveolar capillaritis. There were overlapping manifestations of disease between patients with autoantibodies producing a cytoplasmic pattern and patients with autoantibodies producing a perinuclear pattern; however, the perinuclear pattern occurred more frequently in patients with renal-limited disease. Renal and patient survival was 75% at 24 months, and no difference in survival was seen between patients with renal-limited disease and those with systemic disease. No differences in survival were seen between patients treated with oral cyclophosphamide and those treated with intravenous cyclophosphamide; however, the comparative data from patients treated with corticosteroids alone were inconclusive. In general, autoantibody titers correlated with response to treatment and disease activity, but there were exceptions. CONCLUSIONS: Patients with ANCA have various forms of necrotizing vascular inflammation, ranging from renal-limited disease to widespread systemic vasculitis, including polyarteritis nodosa and Wegener granulomatosis. Oral corticosteroids with either oral or intravenous cyclophosphamide appear to be equally effective therapy for ANCA-associated glomerulonephritis.

Adolescent↗
PubMed1990

Hearing disability in people aged 50-65: effectiveness and acceptability of rehabilitative intervention.

OBJECTIVE: To determine the best means of detecting hearing disability in subjects aged 50-65 and whether rehabilitative intervention is acceptable in this age group. DESIGN: Questionnaire survey of patients on general practice age-sex registers. Two types of questionnaire were used, one being based on the closed set approach of the Institute of Hearing Research questionnaire, which had been used in a pilot study, and the other being a simplified version of this questionnaire developed by the Welsh Hearing Institute and based on open set questions. Questionnaires were sent up to three times, and any patients who had not responded two months after the last posting were personally contacted. SETTING: Two general practices in Glyncorrwg and Blaengwynfi in the Afan valley, West Glamorgan. PATIENTS: 271 Patients in Glyncorrwg (136 men, 135 women) and 333 patients in Blaengwynfi (173 men, 160 women) aged 50-65. INTERVENTIONS: All patients indicating hearing disability in answering the questionnaires were invited to attend for a evaluative session in their village. After audiometric testing advice and arrangements for fitting a hearing aid were offered as appropriate. MAIN OUTCOME MEASURES: Response rates and prevalence of hearing disability before intervention and of possession of hearing aids before and after intervention. RESULTS: After three postings and personal contact the response rate was 98% (266/271) in Glyncorrwg, where the complex questionnaire was used, and 97% (322/333) in Blaengwynfi. The prevalence of hearing disability was respectively 53% (141/266) and 46% (148/322) and the prevalence of owning a hearing aid 7% (19/266) and 8% (24/322). After intervention the possession of hearing aids rose to 24% (64/266) in Glyncorrwg and 22% (71/322) in Blaengwynfi; six months later the aids were being used regularly. A direct comparison of the two questionnaires in 69 subjects from Blaengwynfi showed no significant differences in the amount of disability detected by each one. The first posting of questionnaires detected 65% (189/289) of the hearing disability in the two villages or 78% (72/92) of those prepared to accept hearing aids for the first time; 96% (88/92) of those who accepted hearing aids were detected by two postings. CONCLUSIONS: Simple questionnaires are effective in detecting hearing disabilities in people aged 50-65, and intervention was acceptable in many of those who reported having difficulties in hearing. The response rates from successive postings suggest that two postings are sufficient in terms of the return in detecting those who will accept intervention.

Aged↗
PubMed1990

Early intervention and rehabilitation: factors influencing outcome.

Detection of hearing disability in a pre-retirement working class population of people aged 50-65 years has been achieved using simple questionnaires. Patients who reported disability were offered rehabilitation, including hearing aids, and the hearing aids use increased from 7% to 23% of the population. Those who accepted or refused hearing aids differed only minimally in mean worse or better ear hearing levels, but markedly in terms of hearing handicap. Similarly, those who indicated that they would like help with their hearing had increased disability and handicap levels but hearing levels no different from those who did not want help. Tinnitus in addition to hearing disability increased the individual's acceptance of a hearing aid. Sex, social class and exposure to occupational noise had no significant effect.

Aged↗
PubMed1990

Care for the caregiver: social policies to ease their burden.

The majority of caregivers are women, and a vast number of the households are single-parent, female-headed households. Public policies reward institutionalization of the elderly and penalize "sandwich generation" caregivers. Current state governments support the traditional ideal of the family. This incorrect vision promotes the creation of social policies that do not fit the real picture of a single, female-headed family with elderly parents needing care. "Sandwich generation" caregivers place themselves in jeopardy of poverty in their future years because of their caregiving activities for their elderly parents during their young-old years.

Aged↗
PubMed1989

Initiation and perpetuation of obesity and obesity resistance in rats.

A search was made for predisposing factors and sequelae of diet-induced obesity (DIO) or resistance to DIO (DR). During 3 mo on a high-energy (CM) diet, two-thirds of the male Sprague-Dawley rats ate 16% more calories over the first 30 days and developed DIO. The remaining one-third were DR, gaining the same amount of weight as chow-fed controls. Basal and norepinephrine (NE)-stimulated in vivo O2 consumption, performed before rats were placed on the CM diet, was the same in those rats that later became DR or DIO after 3 mo on the CM diet. DR rats were 4% lighter, whereas DIO rats were equal to chow-fed rats before their exposure to the CM diet. When CM-fed rats were switched to chow, DIO rats took 14 wk to reduce their body and retroperitoneal fat pad weights to those of chow-fed controls, whereas DR rats gained only 40% of the body weight, and fat pads were 34% lighter than controls. After 14 wk, DIO rats were neither hyperinsulinemic nor insulin resistant, whereas DR rats had 64% reduced areas under their insulin curves after intravenous glucose (1 g/kg) compared with controls. Unlike younger rats, animals here had inconsistent plasma NE responses to intravenous glucose. Therefore the CM diet produces DR and DIO states that tend to become self-perpetuating once established.

Animals↗