PubMed Health⌕ Search

Biomedical subjects

P S Richards

Publications and source records attributed to P S Richards.

18 recordsLinked to original sources
PubMed2004

Clinics in diagnostic imaging (101): Multinodular accessory thyroid tissue.

A 71-year-old woman with a strong family history of thyroid cancer presented with 3 months of constipation. A carcinoid tumour of the rectum was found at colonoscopy. On physical examination, she had a large goitre and there was a 3-4 cm firm submental mass. The differential diagnosis was accessory thyroid tissue or a carcinoma metastasis. Staging computed tomography was performed to include the neck, followed by ultrasonography and aspiration biopsy of the submental mass, which confirmed the diagnosis of multinodular accessory thyroid tissue. Differences in aetiology and pathophysiology of accessory thyroid tissue and ectopic thyroid glands are discussed.

Aged↗
PubMed2003

Non-Hodgkin's lymphoma of the nasopharynx: CT and MR imaging.

OBJECTIVE: Nasopharyngeal (NP) non-Hodgkin's lymphoma (NHL) is an uncommon tumour. The aim of the study was to describe the appearances on CT and MR imaging, and identify the features which help to distinguish NPNHL from other NP tumours. MATERIALS AND METHODS: The CT (n=8) and MR (n=10) images of 14 patients with NPNHL were reviewed retrospectively. Patients with NPNHL were divided into primary NPNHL, where the primary tumour was in the NP (n=7) and secondary NPNHL where the primary tumour was at another extranodal site in the head and neck (n=7). All NPNHL were assessed for tumour size and distribution, appearance and local tumour invasion, in addition lymphadenopathy was assessed in primary NPNHL. RESULTS: The NPNHL ranged in size from 20-75 mm (mean of 55 mm for primary and 30 mm for secondary NHL) and were homogeneous on CT in eight (100%) and MR in seven (70%) and mildly heterogeneous on MR in three (30%) patients. NPNHL involved all walls of the NP in 10 (71%) (n=1). Primary NPNHL extended superficially in five (71%) to involve the nasal cavity (n=3) and oropharynx (n=2) and lymphadenopathy was present in five (71%) being bilateral and involving multiple nodal sites (n=4) with necrosis (n=2) and matting (n=3). CONCLUSION: NPNHL is a homogeneous tumour that tends to diffusely involve all walls of the nasopharynx and spread in an exophytic fashion to fill the airway, rather than infiltrating into the deep tissues. Deep tumour infiltration, when it occurs, is found in those patients with primary NHL and is usually limited in extent and of small volume. and extended in an exophytic fashion to fill the NP cavity in six (43%). Deep tumour invasion was present in two (14%) both patients with primary NHL, the extent and volume of this tumour invasion was small and involved the prevertebral muscles (n=2), parapharyngeal fat space (n=1) and skull base Primary NHL more commonly spreads superficially to involve the nasal cavity or oropharynx, lymphadenopathy is frequent and extensive. A large tumour that fills the nasopharynx, with no or minimal invasion into deep structures, and a propensity to extend down into the tonsil, rather than up into the skull base, may suggest the diagnosis of NHL over nasopharyngeal carcinoma.

Adult↗
PubMed2003

Kuttner tumour (chronic sclerosing sialadenitis) of the submandibular gland: sonographic appearances.

Patients with Kuttner tumours present with clinical features simulating a submandibular tumour. This article aims to familiarise sonologists with the sonographic appearances of these tumours, to help in their differentiation from other salivary lesions. In 13 patients with histologically or cytologically proven Kuttner tumours, the features evaluated on sonography included: shape and border of the gland, internal architecture, duct dilatation, presence/absence of calculi and presence and distribution of vascularity. There was diffuse involvement of the submandibular glands in 11 patients and focal involvement in 2. The majority (9 of 11) of the patients with diffuse involvement showed sonographic appearances simulating a "cirrhotic" liver; 2 showed diffuse heterogeneous involvement with duct dilatation and calculus. Doppler showed prominent intraglandular vessels, with no evidence of displacement. Focal lesions (2 of 11) were seen as hypoechoic, heterogeneous "masses," with a radial branching vascular pattern within, on Doppler. In conclusion, sonographic features may help in identifying Kuttner tumours of the submandibular glands.

Adult↗
PubMed2003

Endolymphatic sac tumours.

We present a case of a papillary tumour of the petrous bone. The established terminology for this rare neoplasm is endolymphatic sac tumour (ELST) but the true origin remains controversial. ELSTs are associated with von Hippel-Lindau disease. They are locally invasive, highly vascular and often require endovascular embolization prior to surgery. Both radiologically and histologically ELSTs are easily mistaken for other more common tumours such as paragangliomas and renal or papillary thyroid carcinoma metastases. This is important because local excision is curative.

Adenoma↗
PubMed1996

Development of a method for studying thematic content of psychotherapy sessions.

The authors developed a measure for categorizing the nature of the topic that clients and therapists discuss from moment to moment during psychotherapy. The Counseling Topic Classification System (CTCS) contains 55 topics and 8 emotional categories. It was used to code the thematic content of Donald Meichenbaum's and Hans Strupp's initial therapy sessions with a client named Richard. Our findings provided preliminary evidence that the CTCS is useful for coding the core topic of initial therapy sessions and that thematic content may be an important process and contextual variable. Methods are described for studying thematic content as a contextual variable and for presenting change process and discovery-oriented research findings so that they are more clinically meaningful.

Counseling↗
PubMed1993

Why referred potential heart donors aren't used.

Heart donor demand far exceeds supply. We evaluated donor referrals to 1 organ procurement agency in an attempt to determine why many potential cardiac donors are not used. Of 430 referrals between September 1989 and August 1991, 169 hearts (39%) were harvested. In potential donors ultimately not yielding a heart, 38.7% were unavailable because the family refused to consent to organ donation, 36% were medically unsuitable, and 16.1% did not meet standard brain death criteria. Of the 94 donors not used for medical reasons, 43.6% had cardiac arrest, 17% had hypotension, 12.8% were drug abusers, 6.4% had sepsis, 5.3% had hepatitis, 5.3% had an acute myocardial infarction, 3.2% had low ejection fraction levels, and 2.1% tested positive for human immunodeficiency virus or syphilis (4.3% were not specified). A significant difference (p = 0.001) in racial distribution surfaced; Blacks and Hispanics constituted 27.2% of the donor group but 46.3% of the non-donor group. These data confirm that strategies must be created to continue educating the public and physicians in order to increase consent rates, optimize donor selection, and improve physician awareness of brain death criteria.

Adult↗
PubMed1990

Measurement of cytokine release by human cells. A quantitative analysis at the single cell level using the reverse haemolytic plaque assay.

The reverse haemolytic plaque assay has been adapted to detect and measure the release of such cytokines as interleukin-1, -2 and -6, GM colony-stimulating factor or interferon-gamma by individual human cells derived from either peripheral blood or enzymatically dispersed breast carcinomas. Since each of these peptides is released by more than one cell type, this in vitro assay has been coupled with immunocytochemistry to identify the particular cell type(s) contributing to the release of each cytokine. This technique is useful in (i) obviating the need for purification of a given cell type prior to estimating cytokine release, and (ii) evaluating quantitative differences in secretion amongst cells of a particular type. Such a method has the additional advantage over most alternative methods applied at the single cell level in that the cells remain viable at the end of the assay and can be used in further studies. This assay thus provides a powerful new tool in the investigation of the role of cytokines in both the normal modulation of the immune system and the development of such diseases as neoplasia.

Biological Factors↗
PubMed1989

Heterogeneity of responses to LH-releasing hormone and phorbol ester among rat gonadotrophs: a study using a reverse haemolytic plaque assay for LH.

Protein kinase C (PK-C) has been implicated in the action of LHRH because LHRH-induced release of LH is partially mimicked by phorbol esters which activate PK-C, and reduced in magnitude by inhibitors of PK-C. We have used a reverse haemolytic plaque assay for LH to visualize and compare the direct effects on individual rat gonadotrophs of (1) a 2-h exposure to a range of concentrations of LHRH and phorbol 12-myristate 13-acetate (PMA) and (2) a single maximally stimulatory dose (10 nM) of LHRH or PMA, or LHRH in the presence of inhibitors of PK-C (retinal and isoquinolone sulphonamide; H7) over six consecutive 30-min intervals. Quantitative analysis of the size and number of haemolytic plaques indicated that LHRH induced a dose- and time-dependent increase in the amount of LH release by individual gonadotrophs, with no evidence of the priming effect of LHRH. Stimulation by 10nM LHRH induced recruitment of actively secreting gonadotrophs which reached maximum levels by 90 min. There was a delay of 90-120 min before 10 nM PMA caused a significant release of LH, as assessed by both the size and number of plaques. During the first 30 min of exposure, the presence of 10 microM retinal or H7 augmented LHRH-induced secretion of LH, with the absence of any inhibition of the effects of LHRH until 90-120 min, when both the size and number of plaques were reduced compared with those formed in the presence of LHRH alone.(ABSTRACT TRUNCATED AT 250 WORDS)

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1987

The prevention of cigarette smoking in children: two- and three-year follow-up comparisons of four prevention strategies.

Recent studies have suggested that a prevention program that addresses the social influences that encourage smoking can be effective in deterring cigarette use by adolescents. This study presents 1-, 2-, and 3-year follow-up results from two studies which evaluated three variations of the social influences curriculum and compared them to a health consequences program and a usual-care comparison group. These results suggest that a peer-led, social influences program can restrain smoking among both baseline nonsmokers and baseline experimental smokers at 2 years postintervention. Analyses of attrition data suggest no evidence to threaten the internal validity of these findings, although their generalizability to baseline smokers may be limited.

Adolescent↗
PubMed1986

Matrix fibronectin disruption in association with altered endothelial cell adhesion induced by activated polymorphonuclear leukocytes.

Sequestration of activated polymorphonuclear leukocytes (PMN) within the lung microcirculation may contribute to pulmonary vascular injury following trauma, sepsis, or disseminated intravascular coagulation. In this study cultured rat endothelial cells were utilized to evaluate the effect of PMN activation on endothelial cell attachment. The concept that disruption of the extracellular fibronectin matrix is associated with altered endothelial cell adhesion was also tested. Rat endothelial cells were grown in culture and identified by morphological techniques as well as immunofluorescent staining of Factor VIII R:Ag. Endothelial cells were labeled with 51Cr in order to establish a cell injury assay based on release of free 51Cr or cell-associated 51Cr. PMN activation was verified microscopically and by chemiluminescence activity following phorbol myristate acetate (PMA) or opsonized zymosan exposure. Following incubation with PMA, the leukocytes aggregated, chemiluminesced vigorously, and caused endothelial cell injury and detachment as determined by release of 51Cr-labeled endothelial cells. PMNs exposed to serum-treated zymosan exhibited a more modest chemiluminescence burst which was consistent with their decreased activity to injure the endothelial monolayer. With PMA activation the degree of endothelial detachment from the monolayer increased as a function of time with a plateau observed by 3 hr. Microscopic immunofluorescent analysis of extracellular fibronectin in endothelial cell cultures revealed disruption of the fibrillar matrix fibronectin after incubation with PMA-activated neutrophils in association with endothelial cell disadhesion. Thus, exposure of activated rat PMN to rat endothelial cells in culture induces endothelial damage and an associated disruption of the fibronectin matrix which may contribute to endothelial cell detachment.

Animals↗
PubMed1983

Fibronectin levels during intraperitoneal inflammation.

Fibronectin is a high-molecular-weight opsonic protein known to influence macrophage uptake of nonbacterial particulate matter. The concentration of fibronectin in serum and the quantity of fibronectin in the inflamed peritoneal space were examined in rats after intraperitoneal casein injection. Fibronectin levels were studied in relation to the opsonic activity of the serum, as assayed by the uptake of gelatin-coated. 51Cr-labeled, fixed sheep erythrocytes by adherent peritoneal macrophage monolayers. Intraperitoneal inflammation resulted in a marked increase in peritoneal fluid fibronectin that lasted throughout a 4-day observation period. The opsonic activity of serum also increased after casein challenge at 24, 48, and 72 h. The elevation in the level of fibronectin in the peritoneal space appeared to coincide with or closely precede the maximal increase in concentration of inflammatory peritoneal macrophages. After casein injection, when serum immunoreactive fibronectin increased, an enhancement in phagocytic clearance of blood-borne gelatin-coated test particles was also observed. It is suggested that the elevation of fibronectin in blood during intraperitoneal inflammation may mediate enhanced liver phagocytic function. The increased amount of fibronectin in the inflamed peritoneal space may also influence the phagocytic activity of peritoneal macrophages.

Animals↗
PubMed1983

Alterations of fibronectin and reticuloendothelial phagocytic function during adaptation to experimental shock.

Fibronectin is a large molecular weight glycoprotein that participates in opsonization as well as in adhesive structural tissue support. The effect of repetitive low grade traumatic shock on circulating fibronectin, opsonic activity, and RES phagocytic function was studied in rats during the process of adaptation to trauma. Enhanced hepatic Kupffer cell phagocytic activity was observed in rats that were resistant to trauma. During the adaptation process, serum fibronectin levels, as measured by immunoassay, were altered markedly and manifested a pattern of acute deficiency early post-trauma followed by rebound and sustained elevation of fibronectin greatly in excess of control levels. At the time adaptation to trauma was achieved, the circulating fibronectin was within the normal range. In an in vitro system, livers from adapted rats exhibited increased phagocytic ability. The data suggest that Kupffer cell activation occurs during the development of adaptation to trauma and that increased hepatic RE activity accounts for the overall increase in RES clearance seen in the trauma-adapted animals. Since repetitive low grade trauma, which can lead to adaptation, will cause immunoreactive opsonic fibronectin levels to become substantially higher than normal throughout much of the duration of the adaptation protocol, it is possible that this excessive circulating fibronectin represents a means by which local conditioning of blood vessels to trauma may be achieved. Most likely, this would be due to incorporation of the circulating fibronectin into the insoluble tissue fibronectin pool, which has been recently shown to take place. The findings suggest that RES function and fibronectin may be factors influencing trauma tolerance.

Adaptation, Physiological↗
PubMedDate not supplied

Effect of endotoxin on fibronectin and Kupffer cell activity.

The phagocytic activity of the reticuloendothelial system (RES) in the liver is important in host resistance to shock. Fibronectin is a large molecular weight glycoprotein which influences particulate uptake by phagocytic cells. This study addressed the effect of repeated low-dose endotoxin challenge on immunoreactive fibronectin and reticuloendothelial phagocytic function in rats. Intravenous Escherichia coli endotoxin increased circulating immunoreactive fibronectin by 100% within 24 hr; normalization was within 96 hr. Elevated fibronectin levels at 48 hr were associated with increased plasma opsonic activity as tested by liver slice phagocytic assay and RES stimulation, and in vitro uptake of gelatinized target particles by Kupffer cells in liver slices from endotoxin treated rats was significantly increased. Endotoxin tolerance was produced by repeated low dose challenge with endotoxin for 7 days and was associated with RES stimulation, even though the circulating fibronectin concentrations had returned to normal. By immunofluorescence, insoluble fibronectin was widely distributed in the liver in a pattern analogous to the sinusoidal vascular network. We suggest that increased RES phagocytic activity after low dose endotoxin challenge is due to early elevation of plasma fibronectin and cellular stimulation of phagocytic function followed by a sustained stimulation of Kupffer cells in the presence of normal fibronectin levels. Both cellular and humoral factors may contribute to increased Kupffer cell phagocytic activity during endotoxin tolerance.

Animals↗