PubMed Health⌕ Search

Biomedical subjects

A Watkinson

Publications and source records attributed to A Watkinson.

At least 37 records · Page 2Linked to original sources
PubMed2000

Sjögren's syndrome, cavitating lung disease and high sustained levels of antibodies to serine proteinase 3.

A case is described involving Sjögren's syndrome, high sustained levels of antibodies to serine proteinase 3, and cavitating lung disease. Possible diagnoses accounting for this unusual combination include a novel association of Sjögren's syndrome and Wegener's granulomatosis (suggested by the high and sustained levels of antibodies to serine proteinase 3) or a rare presentation of bronchiolitis obliterans organising pneumonia. Identification of the true nature of the patients illness facilitated more active management and a swift resolution of the clinical problem.

Aged↗
PubMed1999

Stratum corneum thiol protease (SCTP): a novel cysteine protease of late epidermal differentiation.

Proteolytic enzymes play crucial roles in the formation of the stratum corneum barrier tissue and in its subsequent maturation. Despite this, the proteases involved in stratum corneum physiology are not well characterized. Hence, studies were performed to identify these proteolytic enzymes present in the peripheral layers of this tissue using a combination of tape stripping and zymography. Using this approach, a novel human cysteine protease was identified and characterized, and named stratum corneum thiol protease (SCTP). Gelatin zymography revealed that SCTP is composed of two variants with apparent molecular weights of 34 and 35 kDa which do not correspond to any previously described stratum corneum protease. Mechanistically SCTP belongs to the cysteine proteinase class as shown by: (1) acid protease activity, (2) a requirement for mild reducing conditions, and (3) the specific inhibition of activity by E64 and Z-phe-ala-diazomethylketone. Further analysis using concanavalin A affinity chromatography demonstrated that the two 34 and 35 kDa variants are both glycoproteins, which, after removal of the oligosaccharide sidechains with the specific enzyme N-glycopeptidase F, reveal a single active core protease of 32 kDa. SCTP did not crossreact with antibodies raised against the lysosomal cysteine proteases cathepsins B, H or L, thereby distinguishing it from the classical cysteine cathepsins. Localization studies revealed that SCTP is present at all depths in the stratum corneum, thereby precluding microbial contamination as the enzyme source. Moreover, it was also present at all body sites investigated, except for the hyperkeratotic palmoplantar stratum corneum. SCTP was found to be a product of late differentiation in cultured human keratinocytes; the enzyme was synthesized by differentiated calcium-switched cells and secreted into the medium, whereas nondifferentiated basal keratinocytes did not produce this protease. Moreover, human fibroblast cultures did not produce the enzyme, suggesting that SCTP is not produced by the dermis and hence is epidermal specific. The function of SCTP is unknown, but the observed gelatinolytic activity coupled with its secretion into the medium by cultured keratinocytes indicates that physiologically it is responsible for the degradation of extracellular structural proteins. Furthermore, the optimal activity at acid pH suggests that it can function in the acidic environment of the stratum corneum. It remains to be elucidated whether this enzyme has a role in desquamation.

Blotting, Western↗
PubMed1999

Transjugular liver biopsy in the 1990s: a 2-year audit.

BACKGROUND: In view of the changing nature of transjugular liver biopsy, we performed an audit of the safety, adequacy and clinical impact of such biopsies in our centre over a 2-year period from 1995 to 1997. METHODS: One hundred and fifty-seven transjugular biopsies were carried out in 145 patients, with prothrombin time >5 s over control and/or platelet count <50 x 10(9)/L and/or gross ascites. RESULTS: Major complications were two (1.3%) capsular perforations, which were easily plugged with coils without sequelae. Biopsy sample was adequate for histological diagnosis in 90%, inadequate in 6% and technically unsuccessful in 4% of cases. Mean biopsy size was 14.8+/-7.7 (1-51) mm. Adequacy did not differ between cases with and without cirrhosis. Transjugular biopsy had a clinical impact (specific diagnosis or influence on patient's management) in 50% of acute liver disease, 62% of chronic liver disease and 87% of transplant patients (P<0.001). In chronic liver disease, it had a significantly greater clinical impact in cases trying to establish the stage rather than diagnosis (84% vs. 35%, P<0.001). CONCLUSIONS: Transjugular liver biopsy is a safe procedure for high-risk patients providing an adequate liver sample even in cirrhosis. It has a clinical impact in more than 80% of transplant patients and for staging chronic liver disease, but in only 50% (acute) or 35% (chronic) of liver disease when a diagnosis is sought.

Adolescent↗
PubMed1999

Thrombopoietin concentrations are low in patients with cirrhosis and thrombocytopenia and are restored after orthotopic liver transplantation.

BACKGROUND: Thrombocytopenia in cirrhotic patients may be due to deficient production of thrombopoietin. AIMS: To determine the relation between thrombopoietin and thrombocytopenia in cirrhotic patients before and after orthotopic liver transplantation. METHODS: Thrombopoietin concentrations and platelet counts were measured in 43 cirrhotic patients and 21 normal controls and serially for 14 days after transplantation in 23/43 patients. RESULTS: 27 of the 43 patients had thrombocytopenia (platelet count less than 120 x 10(9)/l; group 1) whereas 16 patients had normal platelet count (group 2). Thrombopoietin concentrations were lower in group 1 than in group 2 (92.5 (20.3-286.3) v 226.6 (30.1-848.3) pg/ml, p=0.003) and normal controls (92.5 (20.3-286.3) v 158.3 (22.5-232.9) pg/ml, p=0.028). Post-transplantation thrombopoietin concentrations increased with a peak at day 5. The rise was significant in patients with low pretransplantation platelet count (89.1 (21.29-247.6) to 545.1 (66.2-2569) pg/ml; n=16, p=0.001) but not in those with normal platelet count (262.8 (30.1-848.3) to 315.1 (114-954.6) pg/ml; n=7, p=0.47). No correlation was found pretransplantation between spleen volume and platelet count (r=-0.11, p=0.6) or thrombopoietin concentrations (r=-0.04, p=0.8). However, pretransplantation thrombopoietin concentrations correlated with platelet count (r=0.47, p=0.0015), whereas an inverse correlation was found between peak thrombopoietin concentrations and nadir platelet count (r=-0.41 p=0. 049) post-transplantation. CONCLUSIONS: Inadequate thrombopoietin production may contribute to cirrhotic thrombocytopenia. Thrombopoietin production is restored after liver transplantation leading to the resolution of thrombocytopenia.

Adult↗
PubMed1998

Ultrasound screening for hepatocellular carcinoma (HCC) in cirrhosis: the evidence for an established clinical practice.

Improvement in our current knowledge of epidemiology, natural history and treatment modalities form the background to generalize the use of ultrasound screening in cirrhosis. The cumulative probability of developing cancer is extremely high in cirrhotics and allows to focus screening programs on a well defined risk group thus maximizing cost-effectiveness. This review article highlights scientific evidences in favour of a generalized practice of US screening.

Carcinoma, Hepatocellular↗
PubMed1998

Multidisciplinary approach to biliary complications of laparoscopic cholecystectomy.

BACKGROUND: Bile leaks and bile duct strictures are major complications of cholecystectomy which increased in incidence after the introduction of laparoscopic surgery. The management and outcome of these complications following the introduction of laparoscopic cholecystectomy was reviewed. METHODS: Eighteen patients of median age 45 (range 22-70) years were treated between January 1992 and December 1995. Six patients had a common hepatic duct (CHD) stricture, four following a failed previous repair. Nine patients had bile leaks from bile duct transection (four), cystic stump (four) or segment V duct (one). Two patients had partial bile duct damage with primary sutured repair at time of cholecystectomy. One patient had recurrent haemobilia from a hepatic artery pseudoaneurysm. RESULTS: Cystic stump or segment V leaks were treated successfully by endoscopic stenting (median follow-up 42 months). Roux loop biliary reconstruction was carried out in nine patients: two CHD strictures, three of the four failed primary CHD repairs and four bile duct transections. All had normal liver function test results at median follow-up of 30 months. The two patients with partial duct injuries repaired at initial surgery required no further intervention. The right hepatic artery aneurysm was successfully embolized. There have been no deaths or major complications of endoscopic, radiological or surgical intervention. CONCLUSION: Endoscopic stenting successfully treats cystic stump and segment V duct leaks. Duct strictures, including failed initial repairs and transections, have a good outcome with Roux-en-Y loop reconstruction.

Adult↗
PubMed1997

Effects of Ostertagia ostertagi on gastrin gene expression and gastrin-related responses in the calf.

1. Infection with the bovine abomasal nematode Ostertagia ostertagi results in a loss of acid-secreting parietal cells and an increase in gastric pH. The effects of an experimental infection on gastrin mRNA expression, blood and tissue gastrin concentrations, the different molecular forms of gastrin in each, and pyloric mucosal chromogranin A-derived peptides were investigated in the calf. 2. An increase in blood gastrin concentrations in the infected group reached a peak by day 28 postinfection (635 pg ml-1; P < 0.01). Gel chromatography analysis of blood samples revealed that the hypergastrinaemia comprised largely gastrin-34 (G-34) in parasitized calves while gastrin-17 (G-17) predominated in control animals. 3. An 11-fold increase in gastrin mRNA expression was recorded in the parasitized animals which was accompanied by a 23.8% reduction in pyloric mucosal gastrin content and an apparent drop of 24.7% in the number of gastrin-producing G cells detected. There was no major change in the relative abundance of G-17 and G-34 in the pyloric mucosa of infected calves. No significant differences in the concentration of pyloric mucosal chromogranin A-derived peptides were recorded between infected and control groups. 4. These data suggest that the hypergastrinaemia seen in parasitized calves results largely from an increase in gastrin synthesis and that depletion of previously stored peptide makes virtually no contribution to elevated blood gastrin concentrations.

Animals↗
PubMed1997

Human growth hormone fragment (hGH44-91) produces insulin resistance and hyperinsulinemia but is less potent than 22 kDa hGH in the rat.

A 17 kDa fragment of human growth hormone (22 kDa hGH), identified as hGH44-191, has lower binding affinity for growth hormone receptors (GHRs), but has been reported to be more potent in producing glucose intolerance in yellow obese mice. Out aim was to investigate this anomaly by comparing acute development of hyperinsulinemia and insulin resistance ("diabetogenic activity") during hGH44-191 or 22 kDa hGH infusion in normal rats. Fasted awake make rats (350-370 g) were infused via a carotid cannula with saline (CON), 22 kDa hGH (at 0.125 micrograms/min), or hGH44-191 (at 0.64 or 0.32 micrograms/min) for 5.75 h. Over the last 2 h, a euglycemic hyperinsulinemic clamp (insulin infusion rate 0.25 U/kg/h) was performed. After 3.75 h infusion, 22 kDa hGH at 0.125 and hGH44-191 at 0.64 micrograms/min produced basal (preclamp) hyperinsulinemia compared to CON. During the clamp, insulin resistance was consistently produced by 22 kDa hGH at 0.125 and hGH44-191, at 0.64 micrograms/min compared to CON. Using specific radioimmunoassays for 22 kDa hGH and hGH44-191, we determined that under conditions of equivalent diabetogenic activity, molar circulating levels of hGH44-191 were 50-60-fold higher than 22 kDa hGH. It was concluded that whereas 22 kDA hGH and hGH44-191 are both capable of generating acute hyperinsulinemia and insulin resistance in the normal rat, the diabetogenic potency of hGH44-191 is not enhanced compared to 22 kDa hGH, and that diabetogenic potency is in accord with the reported lower binding affinity of hGH44-191 to the GHR.

Animals↗
PubMed1997

Prior eccentric contractions impair maximal insulin action on muscle glucose uptake in the conscious rat.

Our aim was to examine the effect of prior eccentric contractions on insulin action locally in muscle in the intact conscious rat. Anesthetized rats performed one-leg eccentric contractions through the use of calf muscle electrical stimulation followed by stretch of the active muscles. Two days later, basal and euglycemic clamp studies were conducted with the rats in the awake fasted state. Muscle glucose metabolism was estimated from 2-[14C(U)]deoxy-D-glucose and D-[3-3H] glucose administration, and comparisons were made between the eccentrically stimulated and nonstimulated (control) calf muscles. At midphysiological insulin levels, effects of prior eccentric exercise on muscle glucose uptake were not statistically significant. Maximal insulin stimulation revealed reduced incremental glucose uptake above basal (P < 0.05 in the red gastrocnemius; P < 0.1 in the white gastrocnemius and soleus) and impaired net glycogen synthesis in all eccentrically stimulated muscles (P < 0.05). We conclude that prior eccentric contractions impair maximal insulin action (responsiveness) on local muscle glucose uptake and glycogen synthesis in the conscious rat.

Animals↗
PubMed1997

Alterations in the expression and cellular localization of protein kinase C isozymes epsilon and theta are associated with insulin resistance in skeletal muscle of the high-fat-fed rat.

We have tested the hypothesis that changes in the levels and cellular location of protein kinase C (PKC) isozymes might be associated with the development of insulin resistance in skeletal muscles from the high-fat-fed rat. Lipid measurements showed that triglyceride and diacylglycerol, an activator of PKC, were elevated four- and twofold, respectively. PKC activity assays indicated that the proportion of membrane-associated calcium-independent PKC was also increased. As determined by immunoblotting, total (particulate plus cytosolic) PKC alpha, epsilon, and zeta levels were not different between control and fat-fed rats. However, the ratio of particulate to cytosolic PKC epsilon in red muscles from fat-fed rats was increased nearly sixfold, suggesting chronic activation. In contrast, the amount of cytosolic PKC theta was downregulated to 45% of control, while the ratio of particulate to cytosolic levels increased, suggesting a combination of chronic activation and downregulation. Interestingly, while insulin infusion in glucose-clamped rats increased the proportion of PKC theta in the particulate fraction of red muscle, this was potentiated by fat-feeding, suggesting that the translocation is a consequence of altered lipid flux rather than a proximal event in insulin signaling. PKC epsilon and theta measurements from individual rats correlated with triglyceride content of red gastrocnemius muscle; they did not correlate with plasma glucose, which was not elevated in fat-fed rats, suggesting that they were not simply a consequence of hyperglycemia. Our results suggest that these specific alterations in PKC epsilon and PKC theta might contribute to the link between increased lipid availability and muscle insulin resistance previously described using high-fat-fed rats.

Animals↗
PubMed1996

Facial asymmetry with severe unilateral hypoplasia of the muscles of mastication: a report of clinical and electromyographic findings.

Mild degrees of asymmetry of the human body have been recognised both by classical sculptors and more recently by anatomists as both normal and widely occurring. Morphologic asymmetries of the face of a more severe nature are, however, quite rare. When such deformities occur, both the hard and soft tissues may be involved and the abnormality may be acquired as a result of trauma, infection, neoplasia or surgery or be of a developmental origin as in the syndromes affecting the first pharyngeal arch. Developmental asymmetries of the jaws may also arise as a result of unilateral disruption of mandibular development during the time of normal facial growth leading to hemiretrognathism. Severe hypoplasia of the muscles of mastication on one side only has not previously been reported.

Adolescent↗
PubMed1996

Growth hormone-induced insulin resistance and its relationship to lipid availability in the rat.

The role of increased lipid availability in the generation of insulin resistance by growth hormone has not been established. We investigated this in rats infused with saline (controls) or human growth hormone (hGH) (500 micrograms x kg-1 x 24 h-1) for 5 h or 3 days. hGH infusion increased basal plasma insulin at 5 h (335 +/- 33 vs. 197 +/- 15 [controls]; P < 0.005) and at 3 days (396 +/- 34 vs. 218 +/- 14 pmol/l; P < 0.0001). Plasma nonesterified fatty acid (0.26 +/- 0.01 vs. 0.21 +/- 0.01 [controls] g/l) and liver long-chain acyl-CoA (21.2 +/- 1.9 vs. 14.1 +/- 1.1 [controls] nmol/g wet wt) were elevated at 5 h (P < 0.01 for both) but were below control levels after 3 days of hGH infusion (P < 0.01 for both); indirect calorimetry after 3 days demonstrated decreased lipid oxidation. Clamp studies showed similar degrees of peripheral insulin resistance at 5-h and 3-day hGH infusion (glucose disposal reduced by 25% versus controls). Insulin-stimulated glucose metabolic index (Rg') in red gastrocnemius muscle (red muscle) was reduced (P < 0.05 and P < 0.01) at 5 h and 3 days of hGH infusion, respectively (e.g., 5 h, 10.0 +/- 1.8 vs. 24.1 +/- 4.4 [controls] micromol x 100 g-1 x min-1), whereas insulin-mediated muscle glycogen synthesis was reduced (P < 0.03) only in rats infused with hGH for 3 days. We conclude that in the rat, hGH rapidly induces persistent peripheral insulin resistance and basal hyperinsulinemia. However, the transient nature of increased lipid mobilization suggests that it is not an important factor in the manifestation of muscle insulin resistance during prolonged hGH elevation. The persistent insulin resistance is not associated with increased lipid oxidation but is associated with hyperinsulinemia and reduced insulin-mediated muscle glycogen synthesis.

Adipose Tissue↗