Biomedical subjects

S Humphreys

Publications and source records attributed to S Humphreys.

At least 37 records · Page 2Linked to original sources

PubMed1996

The evaluation of diagnostic and prognostic criteria and the terminology of thin cutaneous malignant melanoma by the CRC Melanoma Pathology Panel.

Sections from 95 skin lesions excised at pigmented lesion clinics in England and Scotland were studied by eight histopathologists in order to evaluate consistency in the use of histopathological terms for features of diagnostic and prognostic importance for cutaneous malignant melanoma. The level of agreement (kappa) amongst the panel improved after discussion and re-definement of criteria for several features. These included, architectural and nuclear atypia, pagetoid infiltration and radial and vertical growth phases. A high level of agreement was achieved for an overall benign or malignant diagnosis (kappa = 0.77) but use of more specific terms such as benign naevi with atypia and melanoma < or = 0.76 mm thickness, was associated with only an intermediate level of agreement. Of the original diagnosis of melanoma, 17% were re-classified by the panel as benign with atypia and 2% reported to be benign were judged to be melanoma. This reflected the high proportion of borderline lesions in the study. The use of standardized diagnostic criteria with precise definitions has been shown to improve consistency in diagnosis and it is recommended for general application. From this should emanate more reliable incidence figures for thin melanoma, and improved understanding of the nature of these early lesions, to the benefit of patient and clinician alike. The poor concordance in distinguishing severe dysplasia in the junctional component of melanocyte proliferations from melanoma in situ and superficial dermal invasion improved only modestly despite intensive efforts. Since melanoma in situ and severe dysplasia cannot be distinguished by objective measurements and since their clinical management is the same, the panel suggests that attempts to separate them in diagnostic reports should be discontinued and they could both be referred to as melanocytic intraepidermal neoplasia (MIN). If it becomes accepted that dermal invasion without a vertical growth component can also be managed identically to MIN, then this invasive radial phase may be appropriately referred to as microinvasion and linked to MIN for the purposes of clinical management.

Biopsy↗

PubMed1996

Sensitive and reliable PCR and sequencing used to detect p53 point mutations in fine needle aspirates of the breast.

AIMS/BACKGROUND: Fine needle aspirates (FNAs) of breast lesions are now a routine investigation and prognostic information at this stage would be useful for accurate management, p53 gene status can be used as prognostic indicator, an abnormal genotype being associated with high grade, oestrogen receptor poor tumours. As the main disadvantage with FNA is poor cellularity, the objective of this study was to develop a sensitive and reliable method for the assessment of the p53 status of the lesion. METHODS: Using PCR and subsequent direct sequencing, a method was developed that enables analysis of the p53 gene from relatively few malignant or suspicious cells in a background of normal cells. RESULTS: This method is both reproducible and sensitive. The sensitivity of the method is demonstrated and a mutant cell can be seen in a background of 90% of normal wild type cells. A mutation, not previously described in breast cancer, is also reported in a symptomatic FNA. CONCLUSIONS: This methodology is reliable and effective on samples with both variable cell numbers and quality of preservation, allowing it to be applied successfully to diagnostic cytology.

Base Sequence↗

PubMed1996

Evaluation of the 2-mm punch biopsy in dermatological diagnosis.

This prospective study was undertaken to determine whether the 2-mm punch biopsy technique yields specimens of sufficient size and quality to allow a reliable histological diagnosis to be made. A histopathological comparison was made between tissue obtained from a 2-mm punch biopsy and a standard ellipse biopsy taken from a wide range of dermatoses and benign and malignant skin tumours. In 79 of the 84 cases studied, the same histopathological diagnosis was reached with the 2-mm punch biopsy and the standard ellipse. Use of the 2-mm punch biopsy technique produces specimens which allow an accurate histological diagnosis to be made in a wide range of dermatological conditions. Skin biopsy techniques should ideally be quick and easy to perform, yielding specimens of high quality and adequate size while leaving the smallest possible tissue defect and a good cosmetic result. The aim of this study was to compare the effectiveness of the 2-mm punch biopsy with that of the standard ellipse biopsy technique in providing skin specimens which permit an accurate pathological diagnosis to be made.

Biopsy↗

PubMed1996

Reproducibility of Bayesian belief network assessment of breast fine needle aspirates.

OBJECTIVE: To assess the consistency of diagnosis of fine needle aspiration biopsies of breast lesions by three experienced and five less experienced pathologists using conventional means and applying a Bayesian belief network (BBN) to 10 diagnostic features to support diagnostic decision making. STUDY DESIGN: Forty fine needle aspiration biopsies, previously assessed by one of the experienced pathologists both conventionally and using a BBN, were assessed by two further experienced pathologists and five less experienced pathologists. RESULTS: Using the BBN, the experienced pathologists arrived at diagnoses in agreement with an established consensus at a slightly lower rate than by conventional means. The less experienced pathologists arrived at the correct diagnoses no more frequently with the help of the BBN than conventionally. CONCLUSION: As used in this study, the BBN did not help less experienced pathologists to interpret their observations but did not enable less experienced pathologists to identify how their observations differed and affected their diagnoses. The prototype system used in this study has since been upgraded by providing computer graphic displays of the features to be observed so that a more uniform mental image can be held by the participating pathologists. This will be tested with the same study design.

Biopsy, Needle↗

PubMed1995

Classification of ductal carcinoma in situ by image analysis of calcifications from digital mammograms.

There is evidence to suggest that non-comedo cases of ductal carcinoma in situ (DCIS) may have a lower risk of progressing to invasive disease than comedo DCIS and may be managed with less radical treatment. Most cases of DCIS present as calcifications on the mammogram and, due to differences in the tumour architecture, comedo calcifications often have a characteristic linear or branching appearance. In this study, computer methods were developed to identify the comedo cases using the imaging features of individual calcifications and of calcification clusters. Classifier performance was measured using the area under the receiver operating characteristic (ROC) curve and was optimized by systematic testing of many different combinations of these features. On a test-set of 42 cases the computer achieved a ROC curve area of 0.91 using six combined cluster features. These results are encouraging given the observed overlap in appearance between the comedo and non-comedo cases.

Breast Diseases↗

PubMed1994

Identification of bone marrow micrometastases in patients with prostate cancer.

BACKGROUND: Thirty percent of patients with clinically localized prostate cancer and a negative bone scan will experience relapse with recurrent disease despite treatment of the primary tumor. This may be due to the presence of metastatic prostate cancer cells at the time of treatment undetected by conventional methods, radionucleotide bone scan, and serum prostatic specific antigen blood test. METHODS: The authors used polymerase chain reaction (PCR) amplification of the prostate-specific antigen (PSA) mRNA sequence reverse-transcriptase PCR (RTPCR) and immunohistochemistry using a PSA antibody to identify metastatic prostate cancer cells in the bone marrow of patients with prostate cancer. RESULTS: Micrometastases were found in the bone marrow of 29 of the 55 patients (51%) with prostate cancer and in 0 of the 5 patients with benign prostatic hyperplasia. Samples from five of the seven patients with lymph node metastases and from all five patients with bony metastases contained micrometastases. Of the samples taken from 43 patients undergoing radical prostatectomy and with no evidence of metastatic disease, 19 (44%) had micrometastases. Four of the 20 samples (20%) from patients with pathologically localized disease and 15 of the 23 samples (65%) from patients with extraprostatic disease had micrometastases (P = 0.003). Bone marrow slides were available on 24 of the 29 patients who were positive for micrometastases by RTPCR: Immunohistochemistry using the PSA antibody identified metastatic cells in 19 of these 24 patients. CONCLUSIONS: Reverse-transcriptase polymerase chain reaction of bone marrow samples from patients with clinically localized prostate cancer may improve the accuracy of prostate cancer staging and identify patients at high risk for metastatic disease.

Base Sequence↗

PubMed1994

Urticaria pigmentosa--response to topical steroids.

A case of adult-onset urticaria pigmentosa is presented, in which the eruption cleared following the application of potent topical corticosteroids. Remission could be maintained by intermittent topical treatment. Topical steroids would appear to provide a simple, cheap and effective alternative to standard therapies.

Adult↗

PubMed1994

Nodular hyperplasia surrounding fibrolamellar carcinoma: a zone of arterialized liver parenchyma.

We report a case of acetaminophen-induced liver necrosis in a 14-year-old girl. At autopsy, a 9 cm subcapsular nodule was present in the right lobe of the liver which showed distinct zonation: a central greyish white area of fibrolamellar carcinoma with a peripheral fleshy, tan-coloured rim ranging from 1 to 2 cm in thickness. This peripheral zone consisted of nodular, hyperplastic parenchyma resembling the changes seen in focal nodular hyperplasia, and stood out from the adjacent necrotic parenchyma. The sparing of this zone from the deleterious effects of acetaminophen provides indirect evidence of a predominantly arterial rather than portal blood supply to this region. The arterial supply was most probably derived from the tumour vasculature and may explain the parenchymal hyperplasia sometimes reported adjacent to a fibrolamellar carcinoma. Awareness of this phenomenon is essential when evaluating a needle biopsy, as sampling of this region may lead to a false negative diagnosis.

Adolescent↗

PubMed1994

Sensitivity of immunohistochemistry and polymerase chain reaction in detecting prostate cancer cells in bone marrow.

Occult micrometastases detected by immunohistochemistry have prognostic significance in patients with localized breast cancer. To determine the usefulness of this technique and of polymerase chain reaction in detecting occult prostate cancer, we evaluated the sensitivity and specificity of immunohistochemistry and polymerase chain reaction amplification of mRNA to detect prostate cancer cells in bone marrow samples. We used cells from an established prostate cancer cell line (LNCAP) mixed with lymphocytes at various dilutions from 10(5) cancer cells in 10(6) lymphocytes to 1:10(6). Both techniques had a 100% specificity and identified cancer cells at all dilutions. Polymerase chain reaction was more sensitive than immunohistochemistry at the lowest dilutions (10(-5) and 10(-6), p = 0.033). We have evaluated seven patients with prostate cancer for micrometastases. Both of the patients with known metastatic prostate cancer and one of the five patients with clinically localized tumors had micrometastases. Detection of micrometastases may be useful in the staging of prostate cancer.

Base Sequence↗

PubMed1994

Commonality of the gene programs induced by effectors of apoptosis in androgen-dependent and -independent prostate cells.

Prostate tissue is composed of both androgen-dependent and -independent cells. To identify the gene program induced by effectors of apoptosis in both of these cell types, we performed differential hybridization on a complementary DNA library prepared from an androgen-independent prostate cancer cell line, AT-3, exposed to ionomycin. Five distinct complementary DNAs representing ionomycin-inducible genes, designated prostate apoptosis response (par) -1, -2, -3, -4, and -5, were identified. Nucleotide sequencing identified par-1 as the rat homologue of a serum- and oxidative stress-inducible gene, 3CH134/erp/CL100; par-2 as the injury-inducible gene HB-EGF encoding a heparin-binding epidermal growth factor-like growth factor; par-3 as the serum-inducible gene cyr-61; whereas par-4 and par-5 were novel, as judged by a GenBank search. par-1, -3, -4, and -5 were also induced in rat ventral prostate following castration, which causes androgen ablation, leading to apoptosis of androgen-dependent prostate cells. Pretreatment of rats with nifedipine prior to castration abrogated inducible expression of the par genes, indicating that their expression was downstream to Ca2+ elevation. Further characterization of these genes revealed that induction of par-4 is apoptosis specific: it is not induced by effectors of growth stimulation, oxidative stress and necrosis, or growth arrest in prostate cells. Together, par-1, -3, -4, and -5 represent an apoptosis response gene program common to both androgen-dependent and -independent prostate cells. Thus, cell death programs in prostate cells are comprised of genes specifically associated with apoptosis as well as those with multifunctional roles in growth regulation. Since elevation of intracellular Ca2+ is central to apoptosis in many cell types, we predict that par genes will be important components of diverse effector-driven apoptotic pathways.

Androgens↗

PubMed1994

Radiation dose associated with spiral computed tomography.

Spiral computed tomography (CT) has recently become available as a practical diagnostic tool; its introduction has created the need for a comprehensive understanding of the magnitude and distribution of the radiation dose to the patient. Dose distributions for conventional and spiral CT were measured with thermoluminescent dosimeters loaded in standard phantoms and then compared to determine the validity of using standard dose descriptors for assessing the dose delivered during spiral CT. Two dose descriptors applied to conventional CT, the CT dose index and the multiple-scan average dose, were found to be adequate for quantifying the dose delivered by spiral CT.

Humans↗

PubMed1993

Modulation of B lymphocyte differentiation by calcitonin gene-related peptide (CGRP). I. Characterization of high-affinity CGRP receptors on murine 70Z/3 cells.

Calcitonin gene-related peptide (CGRP) is a 37-amino acid neuropeptide found in both peripheral and central neurons and in certain endocrine tissues. Previous studies have identified specific high-affinity CGRP receptors on normal T and B cells and have described modulatory effects of CGRP on freshly isolated lymphocytes. In these studies several lymphocyte cell lines were screened for 125I-CGRP binding. One cell line, the murine 70Z/3 pre-B cell line, was found to exhibit a high level of 125I-CGRP binding and was used for further characterization of the lymphocyte CGRP receptor. Several protease inhibitors were evaluated for their ability to stabilize 125I-CGRP binding to 70Z/3 cells. Bacitracin, a relatively nonspecific protease inhibitor, and chymostatin, a cysteine protease inhibitor, enhanced 125I-CGRP binding, suggesting that 70Z/3 cells express a protease capable of inactivating CGRP. 125I-CGRP binding had a linear dependence on cell concentration with binding being detectable with as few as 200,000 cells/ml and was rapid, with equilibrium binding being reached by 30 min. Saturation binding studies demonstrated that the 70Z/3 CGRP receptor has both low- and high-affinity binding states, with Kds of approximately 0.2 and 3.3 nM, respectively. The density of the low-affinity binding site was approximately 20,000 sites/cell and was unchanged following LPS treatment. In contrast, LPS treatment for 48 hr induced a fourfold increase in the density of the high-affinity site, from 105 to 401 sites/cell. In competition binding studies, only CGRP and the CGRP antagonist CGRP8-37 inhibited 125I-CGRP binding, whereas the unrelated neuropeptides calcitonin, SP, and CRH had no effect. Inhibition of 125I-CGRP binding by rat CGRP was best described by a two-site model, with Kis of 44.1 pM and 0.6 nM. Inhibition of binding by human CGRP and CGRP8-37 was best described by a one-site model with Kis of 3.92 and 6.50 nM, respectively. The 70Z/3 CGRP receptor protein was biochemically characterized by affinity labeling the receptor protein with 125I-CGRP and the covalent cross-linking reagents DSS or BS. SDS-PAGE analysis revealed a major band of 103,000 MW. In addition a high-molecular-weight complex which did not penetrate the gel was also observed. The presence of CGRP receptors on 70Z/3 cells provides further evidence for the immunomodulatory role for CGRP and provides a model system for studying the cellular mechanisms of action of CGRP in modulating lymphocyte differentiation and function.

Animals↗

PubMed1993

Modulation of B lymphocyte differentiation by calcitonin gene-related peptide (CGRP). II. Inhibition of LPS-induced kappa light chain expression by CGRP.

The presence of calcitonin gene-related peptide (CGRP) in nerve endings in lymphoid organs, around blood vessels, and in bone marrow suggests that it might influence the function and differentiation of lymphoid cells. Previous studies identified specific CGRP receptors on mature T and B lymphocytes and on 70Z/3 pre-B cells. In these studies, it was found that CGRP stimulated a rapid, prolonged elevation of cAMP with in 70Z/3 cells with an ED50 of approximately 20 fM. Following CGRP treatment, cAMP levels peaked within 5 min and were still elevated after 60 min. The effect of CGRP on surface immunoglobulin (sIg) expression was examined by treating 70Z/3 cells with CGRP, or combinations of CGRP and LPS, and then measuring sIg expression by FACS. When 70Z/3 cells were treated with LPS, CGRP, or calcitonin for 48 hr, only LPS induced the expression of sIg, increasing the percentage of cells expressing sIg from less than 10% positive in untreated cells to 80-98% positive. Subsequent experiments examined the effect of CGRP on LPS-induced sIg. CGRP inhibited LPS-induced sIg expression at concentrations ranging from 10(-15) to 10(-7) M. The maximal inhibition was observed at CGRP concentrations ranging from 10(-10) to 10(-8) M, and the maximal reduction of sIg expression was about 40%. The inhibitory effect of CGRP was specific in that it could not be mimicked by calcitonin and could be blocked by the CGRP receptor antagonist CGRP8-37. A similar dose-dependent inhibitory effect on LPS induction was observed in 70Z/3 cells treated with LPS and dibutyryl cAMP, suggesting that the inhibitory effect of CGRP on sIg expression is mediated by stimulation of intracellular cAMP. The inhibitory effect of CGRP on LPS induction of sIg appears to be mediated by a reduction in the expression of both mu and kappa mRNA. When mu and kappa expression were examined by Northern blot analysis, it was found that CGRP caused a 50% reduction in the amount of mu and kappa mRNA induced by LPS. The ability of CGRP to inhibit differentiation of 70Z/3 cells and sIg expression provides evidence that CGRP can influence the differentiation of lymphopoietic precursors.

Adenylyl Cyclases↗

PubMed1993

An efficient approach to routine TL dosimetry.

A new labour-saving protocol for clinical dosimetric measurements based on the thermoluminescence (TL) of lithium fluoride is presented. The accuracy of dose measurements resulting from the application of this protocol is examined with particular emphasis on the linearity, reproducibility, and fading of TL response. It is shown that the technique described here is capable of yielding an accuracy of +/- 5% at the 95% confidence level for doses in excess of 1cGy. This study establishes that adoption of the protocol can result in significant savings in labour whilst maintaining a level of accuracy that is adequate for clinical dosimetry.

Reproducibility of Results↗

PubMed1991

Characterization of functional calcitonin gene-related peptide receptors on rat lymphocytes.

Calcitonin gene-related peptide (CGRP), a vasoactive neuropeptide present in peripheral neurons, is released at local sites of inflammation. In these studies specific high affinity adenylyl cyclase linked CGRP receptors were characterized on rat lymphocytes. The distribution, affinity, and specificity of CGRP receptors was analyzed by radioligand binding. 125I-[His10]CGRP binding to rat lymphocytes was rapid, reaching equilibrium by 20 to 30 min at 22 degrees C, and dependent on cell concentration. The dissociation constants, Kd, for the CGRP receptor on purified T and B lymphocytes are 0.807 +/- 0.168 nM and 0.387 +/- 0.072 nM and the densities are 774 +/- 387 and 747 +/- 244 binding sites/cell, respectively. Competition binding studies determined that rat CGRP inhibits 125I-[His10]CGRP binding to lymphocytes with the highest affinity (Ki = 0.192 +/- 0.073) followed by human CGRP and the CGRP receptor antagonist CGRP8-37. 125I-[His10]CGRP binding to rat lymphocytes was not inhibited by the neuropeptides substance P, calcitonin, or neuropeptide Y. Lymphocyte CGRP receptor proteins were identified by affinity labeling by using disuccinimidyl suberate to covalently cross-link 125I-[His10]CGRP to its receptor. Specifically labeled CGRP binding proteins visualized by SDS-PAGE analysis had molecular masses of 74.5 and 220 kDa. A third high molecular mass protein band which did not penetrate the gel was also observed. In functional studies, CGRP stimulated a rapid, sustained increase in cAMP with an ED50 of approximately 8 pM. In experiments comparing optimal concentrations of isoproterenol, a beta 2-adrenergic agonist, and CGRP, intracellular cAMP elevation after isoproterenol treatment returned to basal levels by 30 min, whereas cAMP was still elevated at 60 min after CGRP treatment. The response to CGRP was specific in that it could be completely blocked by CGRP8-37. The presence of high affinity functional CGRP receptors on T and B lymphocytes provides evidence for a modulatory role for CGRP in regulating lymphocyte function.

Adenylyl Cyclases↗

PubMed1991

The osteodystrophy of congenital erythropoietic porphyria.

Congenital erythropoietic porphyria (CEP) is a rare disorder of heme biosynthesis that results in the production of large quantities of photoactive porphyrins. The clinical syndrome is dominated by extreme photosensitivity with mutilation of light exposed extremities and hemolytic anemia. Bone disease has been occasionally noted, but is not well characterised. We describe a man with CEP who developed bone pain and spinal crush fractures at the age of 22. Skeletal radiographs revealed features typical of other severe hemolytic anemias, but in addition there was loss of the terminal phalanges of the hand as a result of photomutilation. Spinal bone density (assessed by DPA) was reduced and at the hip bone density was at the lower limit of normal. The metacarpal cortical bone density was 2.9 standard deviations below normal. Biochemical and histological studies accelerated bone turnover. Although the serum 250H vitamin D concentration was very low (because of light avoidance) there was no evidence that the bone disease was a consequence of this. Treatment for one year with clodronate and a high transfusion regime was associated with small reductions in serum alkaline phosphatase and urine hydroxyproline excretion, but there was no improvement in bone mineral density. We conclude that CEP has a distinctive osteodystrophy comprising osteolysis of light-exposed extremities and a high turnover type of osteoporosis. Privational vitamin D deficiency may also occur. The effect upon bone of the new therapies for CEP should be considered.

Alkaline Phosphatase↗

PubMed1990

Monoamine synaptic structure and localization in the central nervous system.

The monoamines dopamine, noradrenaline, adrenaline, and serotonin as well as the diamine histamine have a widespread distribution in the central nervous system within synaptic terminals and nonsynaptic varicosities. In certain regions of the central nervous system the monoamines are contained in varicosities that have no synaptic specialization associated with them, suggesting a possible neuromodulatory role for some of the monoamines. The majority of monoamine labelled structures are synaptic terminals which are characterized by the presence of small, clear vesicles (40-60 nm) and large, granular vesicles (70-120 nm) within the terminal. A third population of vesicles--small, granular vesicles--which are visible only after histochemical staining, are probably the equivalent of the small, clear vesicles present after either autoradiographic or immunohistochemical labelling. Most monoamine containing terminals contact dendrites and dendritic spines and, less frequently, neuronal somata and other axons. Both asymmetrical and symmetrical membrane specializations are associated with monoaminergic terminals; however, asymmetrical contacts are the most frequent type found. These ultrastructural results indicate that monoamine containing terminals and varicosities in general share many common morphological features, but still have diverse functions.

Animals↗

PubMed1990

Hyperparathyroid bone disease in diabetic renal failure.

Hyperparathyroid bone disease is a common complication of end stage renal failure, particularly in patients on maintenance haemodialysis. Several studies have, however, shown a near absence of hyperparathyroid bone disease in diabetic patients who have been receiving haemodialysis for periods of up to 4 years. We have studied biochemical indices of mineral metabolism in 54 consecutive pre-dialysis patients with moderate to severe renal impairment. Deteriorating renal function was associated with developing hypocalcaemia and hyperphosphataemia. Hypocalcaemia was strongly related to increased severe alkaline phosphatase activity (p less than 0.001), suggesting the development of hyperparathyroidism. Five patients with hypocalcaemia and increased alkaline phosphatase were studied in detail. All had elevated serum concentrations of parathyroid hormone and histological signs of hyperparathyroidism on bone biopsy. Three of the patients had low serum 25 hydroxyvitamin D levels with associated osteomalacia, the other 2 patients were notable for their long duration of renal failure. In the long-term (greater than 4 years) we also observed the development of hyperparathyroidism in a small group of diabetic patients maintained on haemodialysis. We conclude that diabetic patients are not uniquely protected against renal osteodystrophy. Although the prevalence of hyperparathyroidism may be lower in diabetic patients than in those with other types of renal disease, the same factors which predispose to bone disease in non-diabetic patients (long duration of renal failure, low serum 25 hydroxyvitamin D and long periods on haemodialysis) also operate in the diabetic population.

Adult↗