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Biomedical subjects

B C Smith

Publications and source records attributed to B C Smith.

At least 19 recordsLinked to original sources
PubMed2001

Managing chronic hepatitis C acquired through intravenous drug use.

We retrospectively reviewed the provision and uptake of hospital services for 253 current and ex-intravenous drug users with hepatitis C virus (HCV). Overall, 237 attended at least one clinic (mean age 32 years, 70% male, 43% on maintenance methadone); 81% had evidence of active viral replication and 137 agreed to a liver biopsy to assess disease severity. Of these 137, 24% had mild chronic hepatitis with a low risk of progression to cirrhosis, but 9% had cirrhosis (mean age 40 years, mean time since initial intravenous drug use 15.8 years). Only 50 of the 100 patients in whom antiviral therapy was indicated, commenced treatment; 18 (36%) have had a sustained virological response. The natural history or response to treatment of chronic HCV in those who acquire it through intravenous drug use is not different to that previously reported for post-transfusion HCV. However, a substantial proportion default from follow-up or decline further intervention. As intravenous drug use is now the main risk factor for acquisition of HCV, these data have implications for future delivery of care aimed at limiting the morbidity of chronic HCV, and limiting the spread of hepatitis C virus infection amongst intravenous drug users.

Adolescent↗
PubMed2001

Introduction to DNA analysis.

This article discusses the specific use of DNA analysis as one scientific method used in solving crime. Case studies presented here provide examples of crime investigations where the use of DNA analysis can prove beneficial.

DNA↗
PubMed2000

Time for a new paradigm in pediatric medical education: teaching neonatal resuscitation in a simulated delivery room environment.

OBJECTIVES: Acquisition and maintenance of the skills necessary for successful resuscitation of the neonate are typically accomplished by a combination of completion of standardized training courses using textbooks, videotape, and manikins together with active participation in the resuscitation of human neonates in the real delivery room. We developed a simulation-based training program in neonatal resuscitation (NeoSim) to bridge the gap between textbook and real life and to assess trainee satisfaction with the elements of this program. METHODS: Thirty-eight subjects (physicians and nurses) participated in 1 of 9 full-day NeoSim programs combining didactic instruction with active, hands-on participation in intensive scenarios involving life-like neonatal and maternal manikins and real medical equipment. Subjects were asked to complete an extensive evaluation of all elements of the program on its conclusion. RESULTS: The subjects expressed high levels of satisfaction with nearly all aspects of this novel program. Responses to open-ended questions were especially enthusiastic in describing the realistic nature of simulation-based training. The major limitation of the program was the lack of fidelity of the neonatal manikin to a human neonate. CONCLUSION: Realistic simulation-based training in neonatal resuscitation is possible using current technology, is well received by trainees, and offers benefits not inherent in traditional paradigms of medical education.

Delivery Rooms↗
PubMed1998

Primary ameloblastoma of the sinonasal tract: a clinicopathologic study of 24 cases.

BACKGROUND: Ameloblastomas are locally aggressive jaw tumors with a high propensity for recurrence and are believed to arise from the remnants of odontogenic epithelium. Extragnathic ameloblastomas are unusual and primary sinonasal tract origin is extraordinarily uncommon. METHODS: Twenty-four cases of ameloblastoma confined to the sinonasal tract were retrieved from the Otorhinolaryngic-Head & Neck Pathology and Oral-Maxillofacial Pathology Tumor Registries of the Armed Forces Institute of Pathology between 1956 and 1996. RESULTS: The patients included 5 females and 19 males with an age range of 43-81 years, with a mean age at presentation of 59.7 years. The patients presented with an enlarging mass in the maxillary sinus or nasal cavity (n = 24), sinusitis (n = 9), or epistaxis (n = 8). Unilateral opacification of the maxillary sinus (n = 12) was the most common radiographic finding. Histologically, the tumors exhibited the characteristic features of ameloblastoma, including peripherally palisaded columnar cells with reverse polarity. The majority of the tumors showed a plexiform growth pattern. Fifteen tumors demonstrated surface epithelial derivation. Surgical excision is the treatment of choice, ranging from conservative surgery (polypectomy) to more aggressive surgery (radical maxillectomy). Five patients experienced at least 1 recurrence, usually within 1 year of initial surgery. With follow-up intervals of up to 44 years (mean, 9.5 years), all 24 patients were alive without evidence of disease or had died of unrelated causes, without evidence of disease. CONCLUSIONS: Primary ameloblastoma of the sinonasal tract is rare. In contrast to their gnathic counterparts, sinonasal tract tumors have a predilection for older age men. Therapy should be directed toward complete surgical resection to prevent local tumor recurrence.

Adult↗
PubMed1998

Heterozygosity for hereditary hemochromatosis is associated with more fibrosis in chronic hepatitis C.

Hepatic iron has been associated with more aggressive liver disease in chronic viral hepatitis. We evaluated whether the recently described C282Y mutation of the hemochromatosis gene, designated HFE (responsible for at least 83% of hereditary hemochromatosis), was associated with more advanced liver disease in chronic hepatitis C. One hundred thirty-seven patients with biopsy-proven chronic hepatitis C were studied and liver biopsies scored for necroinflammation (grade 0-18) and fibrosis (stage 0-6). Genomic DNA was amplified by polymerase chain reaction and the C282Y mutation identified by restriction with RsaI and electrophoretic separation of restriction fragments. Ten (7.3%) patients had the C282Y mutation. No C282Y homozygous patients were identified. Age, sex distribution, and estimated weekly alcohol consumption were not significantly different between those with and without the mutation. Serum ferritin was higher in the heterozygotes (mean, 339 microg/L) compared with homozygous wild types (153 microg/L; P = .0005). In the majority of patients, liver iron was graded 0 out of 4, but hepatocyte iron staining was more commonly present in heterozygotes compared with homozygous normals (30% compared with 4% [P = .02]). Liver disease was more advanced in those with the mutant allele (mean fibrosis stage: 3.6, compared with wild type: 1.5 [P = .01]). Cirrhosis was found more often in those with the mutation (40%) compared with those without (8.7%) (P = .01; odds ratio: 7.6 [1.9-31.2]). There was no significant difference in inflammation scores between heterozygotes and wild type (mean, 5.4 compared with 4.1). Hepatitis C virus (HCV)-RNA titers were measured by branched DNA assay (HCV RNA 2.0-Chiron), and there was no difference between heterozygous and homozygous normal patients. Thus, despite relatively minor increases in iron stores, individuals who are heterozygous for hemochromatosis appear to develop more fibrosis in chronic hepatitis C. Venesection may be useful therapy in this subgroup.

Adult↗
PubMed1997

Outcome of post-transfusion hepatitis C: disease severity in blood-component recipients and their implicated donors.

The UK 'Look-back Program' identifies recipients of blood products from hepatitis C antibody (anti-HCV) positive donors. Of 60 such recipients tested by the Newcastle Transfusion Service, 28(46.7%) were anti-HCV-negative, 25(41.7%) were anti-HCV-positive, and seven (11.6%) had equivocal serology. We studied 29 anti-HCV-positive/indeterminate recipients and eight of their implicated donors, using serial liver function tests (LFTs), liver histology when clinically indicated, HCV RNA and serotyping. Presumed resolved hepatitis C, with persistently normal LFTs and negative HCV RNA, was found in 28%, of whom 63% had indeterminate anti-HCV by RIBA (1 band of 4 detected on third-generation recombinant immunoblot assay). Resolved hepatitis C was significantly more common in women (p < 0.05) and tended to be associated with younger age at transfusion. There was complete concordance in serotype between donor-recipient pairs. There was no correlation in disease severity between recipients and their implicated donors, nor between recipients from the same donor. A history of alcohol consumption above recommended 'safe' limits (median 30 units) was associated with more severe histological disease (p < 0.01). Host factors, including gender and alcohol consumption, may be important in determining the wide variability in outcome of post-transfusion hepatitis C.

Adolescent↗
PubMed1996

Sclerosing polycystic adenosis of major salivary glands. A clinicopathologic analysis of nine cases.

We describe nine cases of a histologically distinct and previously unreported lesion of the major salivary glands. The patients ranged in age from 12 to 63 years and included four males, five females. The lesions were slow-growing masses in the parotid gland (eight cases) and submandibular gland (one case). The clinical impression in each case was a benign salivary gland tumor. Grossly, the lesions were discrete, pale, rubbery nodules embedded within the salivary gland parenchyma. Microscopically, the lesions were unencapsulated, circumscribed masses of sclerotic and hyalinized collagenous tissue. Irregularly distributed throughout the collagenous tissue in a vaguely lobular pattern were hyperplastic ductal and acinar elements that were usually accompanied by cystically ectatic ducts. The dilated ducts frequently showed apocrine-like metaplasia and epithelial hyperplasia, which often formed transluminal bridges in a cribriform pattern. This epithelial hyperplasia sometimes surrounded eosinophilic globules as seen in so-called collagenous spherulosis. The combination of fibrosis, epithelial hyperplasia, and cystic changes were reminiscent of fibrocystic changes of the breast. Focally, acinar elements contained large, intensely eosinophilic, periodic acid-Schiff's-positive, intracytoplasmic granules believed to represent altered zymogen granules. A sparse to focally intense lymphocytic infiltrate accompanied the epithelial proliferations. Previous interpretations of these masses have included mucoepidermoid carcinoma, low-grade adenocarcinoma, benign adenoma, and mixed tumor. The limited available follow-up suggests that this process has a favorable prognosis despite recurrences in two cases. It is postulated that these lesions represent a pseudoneoplastic condition that results in both fibrosis and epithelial proliferation. We suggest the term sclerosing polycystic adenosis for these rare lesions.

Adolescent↗
PubMed1996

Langerhans cell histiocytosis of the thyroid: a series of seven cases and a review of the literature.

Langerhans cell histiocytosis is a rare disorder, with a few reports describing isolated thyroid gland involvement. We report seven cases, which included four females and three males ranging in age from 2 months to 55 years, with a median age of 37 years. Histologically, the cases demonstrated either diffuse or focal involvement of the thyroid gland by Langerhans cell histiocytes, characterized by bean-shaped, lobated, folded nuclei. In association with the histiocytic infiltrate, there was a prominent eosinophilic cellular component, as well as destruction of the thyroid follicles. All cases occurred in a background of lymphocytic thyroiditis. One case demonstrated adenomatoid nodules, whereas another had a microscopic papillary carcinoma. Immunohistochemical staining demonstrated positive reactivity with S-100 protein, lysozyme, and KP-1. Four patients with isolated thyroid disease, treated by surgical resection alone, are alive without systemic disease from 3 to 19 years after initial presentation. The three patients with systemic disease died within 1 year of the initial diagnosis with disease-related complications. Localized disease portends a favorable prognosis as compared to the thyroid involvement as part of systemic disease.

Adult↗
PubMed1996

Preventing endoscopic retrograde cholangiopancreatography related sepsis: a randomized controlled trial comparing two antibiotic regimes.

Current antibiotic prophylaxis for endoscopic retrograde cholangiopancreatography (ERCP) is not standardized and may be inadequate. We aimed to evaluate the efficacy of 3 days of additional oral antibiotics in the prevention of ERCP-related sepsis. One hundred and fifty-six patients were randomized prospectively to receive either intravenous ticarcillin and clavulinic acid (Timentin; SmithKline Beecham, Dandenong, Victoria, Australia), pre-ERCP (group I) or Timentin and 3 days of oral amoxycillin and clavulinic acid (Augmentin; SmithKline Beecham, Dandenong, Victoria, Australia), group II). Blood cultures were taken 30 min after the procedure. The occurrence of sepsis, defined as a temperature over 38 degrees C, occurring in the first 7 days was recorded and the risk factors for the development of sepsis were evaluated. Four patients had significant positive blood cultures despite the prior administration of Timentin. Sepsis occurred in 10% of group I patients, but only 3% of group II patients (relative risk 3.30; 95% confidence intervals 0.74-14.8). The performance of sphincterotomy and the presence of common bile duct stones were significant risk factors for the development of sepsis. We would recommend 3 days of additional oral Augmentin after a single dose of intravenous antibiotics in patients at increased risk of sepsis, which would include those with bile duct stones and/or those undergoing a therapeutic procedure.

Amoxicillin↗
PubMed1995

Evaluation of blood donors with equivocal hepatitis C serological results.

OBJECTIVE: To characterise blood donors with equivocal hepatitis C serological results and to develop an algorithm for their diagnosis and follow-up. DESIGN: Prospective case survey. SUBJECTS AND SETTING: 100 consecutive blood donors referred to the St Vincent's Hospital Liver Clinic, Victoria, with equivocal hepatitis C serological results (positive result for second generation Abbott Enzyme Immunoassay 2.0, but at least one negative result on supplemental testing by first generation Abbott neutralisation assay and Abbott Supplemental Assay for antibody to specific viral antigens). OUTCOME MEASURES: Percutaneous risk factors for hepatitis C exposure, peak serum alanine aminotransferase (ALT) levels, results of alternative immunoassay (Monolisa) and polymerase chain reaction (PCR) to detect hepatitis C viraemia. RESULTS: Thirty subjects had positive results for alternative immunoassay. A risk factor was identified for 32 subjects and was significantly associated (P < 0.01) with positive results for alternative immunoassay (23/32) and PCR (11/32), abnormal ALT levels (7/32), and strong reactivity on initial immunoassay (23/32). Presence of antibodies to both structural and non-structural antigens was also associated with risk factors and positive alternative immunoassay results. CONCLUSIONS: A definitive diagnosis was possible in 87% of subjects. A diagnosis of hepatitis C infection was based on positive alternative immunoassay results together with positive PCR results or presence of a risk factor. Hepatitis C was excluded for 60% of patients. The diagnosis for the remaining 13% remained indeterminate, indicating the need for a definitive diagnostic test for hepatitis C.

Adult↗
PubMed1995

Ectomesenchymal chondromyxoid tumor of the anterior tongue. Nineteen cases of a new clinicopathologic entity.

We present 19 cases of a previously undescribed myxoid tumor of the anterior tongue. These lesions occurred in nine women and 10 men aged 9 to 78 years (median, 32 years). Most tumors were seen as slow growing, painless nodules in the anterior dorsal tongue. The duration of growth ranged from a few months to 10 years. All tumors were treated by surgical excision, and two recurred. Microscopically, they exhibited a lobular proliferation of ovoid and fusiform cells, which often had multilobated nuclei and occasional foci of atypia, in a chondromyxoid background. Some tumors entrapped muscle or nerve fibers and had a tendency for blunt infiltration of adjacent tissue. The cells were diffusely and intensely immunoreactive for glial fibrillary acidic protein (GFAP) and cytokeratin but were decorated less frequently with antibodies for smooth muscle actin and S-100 protein. Reactivity for epithelial membrane antigen and desmin was not found. We believe these tumors fail to meet established clinicopathologic criteria for any existing myxoid neoplasms of the tongue, including nerve sheath myxoma, myoepithelioma, benign mixed tumor, ossifying fibromyxoid tumor of soft parts, extraskeletal myxoid chondrosarcoma, and glial and chondroid choristomas or heterotopias. Although the histogenesis of this neoplasm is unclear, we suspect that a cell of undifferentiated ectomesenchyme is the progenitor and suggest the descriptive term ectomesenchymal chondromyxoid tumor (ECT) of the anterior tongue be adopted.

Adult↗
PubMed1995

Outpatient liver biopsy using ultrasound guidance and the Biopty gun is safe and cost effective.

BACKGROUND: The need for liver biopsy is increasing with the increasing availability of treatments for liver disease, in particular interferon. For this reason the procedure must be efficient and economical, as well as safe. AIMS: Firstly to assess the safety of outpatient liver biopsy when performed with ultrasound guidance and the 'Biopty' gun. Secondly, to compare the cost of an outpatient and inpatient procedure. METHODS: Two hundred and fifty consecutive liver biopsies performed over a two year period at St Vincent's Hospital, Melbourne were reviewed retrospectively. Indications, histological findings and complications were recorded. RESULTS: Seventy per cent of the biopsies were performed as an outpatient procedure. There were no major complications. Four patients experienced prolonged pain post biopsy. The average cost for an outpatient biopsy was $351, the cost of an inpatient (overnight stay) was $690. CONCLUSION: Outpatient liver biopsy is safe and cost effective, with minor complications in 1.6%. The routine use of ultrasound guidance and the Biopty gun is likely to contribute to these favourable results.

Adult↗
PubMed1995

Management of the chronic hepatitis B carrier.

Chronic hepatitis B is an increasingly prevalent disease in Australia, both because of inadequacies of the current vaccination program, and because of changing population demographics. Regular follow-up of these patients is indicated, particularly as we now have effective anti viral therapy available. The unfavourable disease outcome in about 30% of hepatitis B carriers warrants increased recognition and observation of this group of patients.

Carrier State↗
PubMed1994

Sterols of eustigmatophytes.

The oyster cannot synthesize sterols from smaller molecules but must obtain them from its diet, which consists of detritus and small organisms, i.e., mostly single-celled algae. Algae differ widely in their effectiveness as oyster food. Small (< 5 microns) algae which are abundant in sterols and polyunsaturated fatty acids appear to be most effective. Recent studies have shown the occurrence of cholesterol in strains of the unicellular algae Tetraselmis, Chaetoceros and Skeletonema, sometimes in large quantities. In the study reported here, six isolates of a recently constructed algal class, the Eustigmatophyceae, have been examined for sterols and fatty acids by gas chromatography and gas chromatography/mass spectrometry. All strains were shown to contain cholesterol as the principal sterol. Two isolates contained large amounts of total sterol (400-1000 fg/cell), and one (Sticho 0-18) also contained large amounts of eicosapentaenoic acid (20:5n-3). These biochemical characteristics are desirable in a potential food source for oysters.

Animal Feed↗