Expression of insulin-like growth factor II (IGF–II) in human hepatocellular carcinomas: An immunohistochemical study

Recent results obtained using molecular biology techniques have suggested a possible role for insulin-like growth factor II (IGF-II) in the pathogenesis of hepatocellular carcinoma (HCC). To investigate this phenomenon, a monoclonal anti-body was used against IGF-II to study 54 patients with HCC. The presence of HBsAg was also tested both in serum and liver tissue. A positive immunoreaction was found in 9/15 (60%) of the HCC arising in cirrhotic livers of patients who had serum markers for HBV (HBV+ positive patients). These results provide further evidence that HBV might play a role in the expression of IGF-II. In HCC of patients without any markers of HBV infection (HBV- negative patients), IGF–II was detected in 10/39 (25.6%) of the tumors, and in some benign neoplastic lesions. It was found not only in neoplastic cells but also in some dysplastic nodules. The speculation arises that IGF–II expression may play a role in some steps of hepato-carcinogenesis.     

SK&F 95654-induced acute cardiovascular toxicity in Sprague-Dawley rats--histopathologic, electron microscopic, and immunohistochemical studies

The characteristics and pathogenesis of the cardiovascular toxicity induced by the type III selective phosphodiesterase inhibitor SK&F 95654 were examined in 2 studies. Sprague-Dawley rats received either a single sc injection of 50, 100, or 200 mg/kg SK&F 95654 and were euthanized at 24 hours after administration of the drug (Study 1), or were given a single subcutaneous (sc) injection of 100 mg/kg SK&F 95654 and euthanized at 1, 2, 4, 6, 8,12, 24 hours, or 2 weeks after treatment (Study 2). Control rats received either DMSO or saline. Myocardial lesions and vascular lesions of the mesentery, spleen, and pancreas were seen 24 hours after dosing with either 50,100, or 200 mg/kg SK&F 95654. The frequency and severity of these lesions (evaluated after the 100 mg/kg dose) increased with time over a period of 1 to 24 hours. By 2 weeks, the lesions subsided. Cardiac lesions consisted of myocyte necrosis with hypercontraction bands, inflammatory cell infiltration, interstitial hemorrhage, and interstitial edema. Vascular lesions of the mesentery were most prominent and consisted of vasodilatation and inflammation in the small-sized vessels, arterial medial necrosis and hemorrhage, and venous thrombosis. The vascular lesions included: leukocyte adhesion to endothelial cells, transendothelial migration of leukocytes, and inflammatory cell infiltration into vessel walls. Affected vessels included arteries, terminal arterioles, capillaries, postcapillary venules, and veins. Apoptosis of endothelial and smooth muscle cells was detected in the mesenteric vasculature by both TUNEL assay and electron microscopy. Evidence of endothelial cell activation in the mesenteric arteries and veins was also observed by electron microscopy. Immunohistochemical staining detected enhanced endothelial cell expression of intercellular adhesion molecule- 1 (ICAM- 1) and von Willebrand factor (vWF) in the mesenteric arteries and veins. Mast cells were noted to be more prevalent in affected mesenteric tissue from drug-treated animals. The present findings suggest that apoptosis of endothelial and smooth muscle cells, activation of endothelial cells, recruitment of mast cells, and increased expression of adhesion molecules are important factors to the overall pathogenesis of SK&F 95654-induced vasculitis.     

Pharmacokinetics of rhuMAb CD18, a Recombinant Humanised Monoclonal Antibody Fragment to CD18, in Normal Healthy Human Volunteers

Background and Objectives: Leucocyte β2 integrin adhesion receptors are hypothesised as a therapeutic target to modify immune responses to ischaemia-reperfusion injury that may be detrimental to recovery in a variety of disease states. Two phase I studies were designed to evaluate the pharmacokinetics, immunogenicity and safety of rhuMAb CD18, ahumanised monoclonal antibody F(ab’)₂ fragment to the CD18 receptor, in normal healthy human volunteers. Study Design and Methods: The first study evaluated six escalating doses of rhuMAb CD18 (0.06, 0.12, 0.25, 0.5, 1.0, 2.0 mg/kg) in 36 subjects given two intravenous (IV) bolus injections 12 hours apart. In the second study, 16 subjects received IV doses of 1.0 and 2.0 mg/kg as a single dose or as two doses given 12 hours apart. Study endpoints were rhuMAb CD18 serum pharmacokinetics, change in white blood cell (WBC) count, and safety and tolerability. The two studies enrolled a total of 53 subjects. Results: Serum concentration-time profiles demonstrated a monophasic decline and were best characterised by a one-compartment pharmacokinetic model. At the doses administered, the volume of distribution approximated the serum volume (range of means: 42 to 58 ml/kg). The serum clearance decreased with increasing dose until becoming consistent at doses of 0.5 to 2.0 mg/kg (range of means: 3.1 to 5.0 ml/h/kg). At doses of 0.5 to 2.0 mg/kg, the mean elimination half-life ranged from 7.0 to 9.6 hours. WBC counts increased at doses of above 0.06 mg/kg, returning to within 20% of predose values by day 7. Antibodies to rhuMAb CD18 were not detected at day 28. Mild-to-moderate adverse events were observed in both the placebo and treated groups, and were limited to flu-like symptoms. One subject experienced a serious adverse event (febrile reaction) and recovered with minimal intervention. There was no evidence of an increase in infection in subjects who received rhuMAb CD18. Conclusions: Upon IV bolus administration, rhuMAb CD18 serum concentration-time data fit a one-compartment pharmacokinetic model. At doses of 0.5 to 2.0 mg/kg, the pharmacokinetics were linear and the half-life ranged from 7.0 to 9.6 hours with a volume of distribution that approximated the serum volume. No antibodies to rhuMAb CD18 were detected. A transient, dose-dependent increase in the WBC count was observed, consistent with the expected effect of rhuMAb CD18 on leucocyte demargination. No increase in infection was observed. rhuMAb CD18 administered by IV bolus was well tolerated, with the exception of one febrile reaction.     

Triploidy syndrome: A report on two live-born (69, XXY) and one still-born (69, XXX) infants

Two live-born cases, 69,XXY and one stillbirth, 69,XXX are reported. Further evidence is presented to delineate the triploidy syndrome. Common external and internal features which characterize the triploidy syndrome are low-set ears, hypertelorism, colobomata, syndactyly, simian creases, microphallus, undescended testes, scrotal aplasia, anomalous heart and hypoplasia of kidneys and adrenals. The triploidy syndrome encompasses features found in trisomies 13, 18 and 21. We suggest that the abnormal development of the triploidy infants is the result of the mentioned trisomies and their subsequent effect on the remaining genome.     

Evidence on major gene control of cortical index in pedigree data from Middle Dalmatia,Croatia

It was recently reported that the inheritance of the metacarpal cortical index (CI) in the Chuvashian population can be described in terms of a major gene (MG) model. By applying transmission probability tests, the hypothesis was accepted that not only baseline level of CI but also its sex‐specific dependence on age were under control of the same putative large‐effect gene. Using a pedigree sample from the population of the islands of Middle Dalmatia, Croatia (847 observed individuals in 278 pedigrees), data are presented to support the above findings. The following hypotheses were accepted: (i) inheritance of baseline CI in the Croatian population can be attributed to the effect of a MG responsible for about 42% of the variation; (ii) the same MG takes part in the control of the dependence of CI on age, particularly the age at onset of involutive bone changes (inflection point), and of the rate of decrease in CI with age (slope coefficient). Issues related to the assortative mating effect on CI and the determination of the most parsimonious model are discussed. Am. J. Hum. Biol. 13:398–408, 2001. © 2001 Wiley‐Liss, Inc.     

Nitric oxide mediates intestinal hyperaemic responses to intraluminal bile-oleate

It has long been recognized that intestinal blood flow increases at mealtimes. Mesenteric hyperaemia is also evoked by activation of sensory peptidergic nerves. Our studies explored the possible role of endogenous nitric oxide (NO) in the rat intestinal vasodilator response to luminal instillation of an oleic acid plus bile mixture before and after acute intrajejunal instillation of capsaicin and after chronic pretreatment with capsaicin. In anaesthetized rats we measured jejunal blood flow (BF) with an ultrasonic Doppler flowmeter and systemic arterial pressure (AP) with a pressure transducer. Intestinal perfusion with 80 mM oleic acid in bile increased BF by 98±12%. Instillation of 4 mg of capsaicin into the jejunal lumen initially increased BF by 42±9% but was followed by vasoconstriction. Inhibition of NO synthase with 25 mg/kg i.v. N-nitro-L-arginine (L-NNA) decreased BF by 27±5% and increased AP by 37±11%. After treatment with L-NNA and after acute and chronic administration of capsaicin, the bile-oleate-induced maximal increases in BF above control levels were 42±7%, 65±12%, and 58±8%, respectively. The observed inhibitory effect of L-NNA on the intestinal hyperaemic response to the bile-oleate mixture was reversed by pretreatment with L-arginine (100 mg/kg i.V.). In capsaicin pretreated rats the subsequent bile-oleate-induced hyperaemia was reduced in magnitude but the inhibitory effects of L-NNA were proportionately the same as in animals not receiving capsaicin. These findings support the hypothesis that NO is involved with bile-oleate-induced mesenteric hyperaemia.     

Acculturation and psychosocial stress show differential relationships to insulin resistance (HOMA) and body fat distribution in two groups of blacks living in the US Virgin Islands

The objective of this study was to determine whether acculturation and psychosocial stress exert differential effects on body fat distribution and insulin resistance among native-born African Americans and African-Caribbean immigrants living in the US Virgin Islands (USVI). Data collected from a non-diabetic sample of 183 USVI-born African Americans and 296 African-Caribbean immigrants age > 20 on the island of St. Croix, USVI were studied. Information on demographic characteristics, acculturation and psychosocial stress was collected by questionnaire. Anthropometric measurements were taken, and serum glucose and insulin were measured from fasting blood samples. Insulin resistance was estimated by the homeostasis model assessment (HOMA) method. The results showed that in multivariate regression analyses, controlling for age, education, gender, BMI, waist circumference, family history of diabetes, smoking and alcohol consumption, acculturation was independently related to logarithm of HOMA (InHOMA) scores among USVI-born African Americans, but not among African-Caribbean immigrants. In contrast, among USVI-born African Americans psychosocial stress was not significantly related to InHOMA, while among African-Caribbean immigrants psychosocial stress was independently related to InHOMA in models that included BMI, but not in those which included waist circumference. This study suggests that acculturation and psychosocial stress may have a differential effect on body fat distribution and insulin resistance among native-born and immigrant blacks living in the US Virgin Islands.     

Signalling during hypoxia in human T lymphocytes – critical role of the src protein tyrosine kinase p56Lck in the O2 sensitivity of Kv1.3 channels

T lymphocytes encounter hypoxia when they migrate to pathological sites such as tumours and wounds. The inability of T cells to provide an efficient defence at these sites can in part be explained by the hypoxic environment. Kv1.3 channels, important components of the T cell activation process are inhibited by hypoxia and their inhibition accounts for a hypoxia-induced decrease in T cell proliferation. Although Kv1.3 channels play a key role in T cell O₂ sensing, the signalling mechanisms mediating their response to hypoxia are still not understood. In this study, we show that the src-protein tyrosine kinase p56Lck (Lck) is required for Kv1.3 channel response to hypoxia. Pre-exposure to the src inhibitor PP2 abolished the hypoxia-induced inhibition of Kv1.3 channels in primary human T lymphocytes. Moreover, Kv1.3 channel sensitivity to hypoxia was lost in Lck-deficient Jurkat T cells. Further studies with recombinant Kv1.3 channels showed that Kv1.3 channels lack intrinsic O₂ sensitivity, but delivery of Lck into the cells and transfection of a constitutively active Lck (Y505FLck) restored their sensitivity to hypoxia. Although Lck is necessary for the Kv1.3 channel response to hypoxia, it does not directly inhibit Kv1.3 channels. Indeed, under normal oxygen tension, delivery of active Lck into L929 cells and overexpression of Y505FLck did not decrease recombinant Kv1.3 currents. On the contrary, activation of endogenous src kinases increased wild-type Kv1.3 currents in T lymphocytes. Our findings indicate that Lck is required for the acute response to hypoxia of human T lymphocytes as it is necessary to confer O₂ sensitivity on Kv1.3 channels.