Nabil Hailat

High levels of p19/nm23 protein in neuroblastoma are associated with advanced stage disease and with N-myc gene amplification.

The gene encoding a novel protein designated nm23-H1, which was recently identified as identical to the A subunit of nucleotide diphosphate kinase from human erythrocytes, has been proposed to play a role in tumor metastasis suppression. We report that untreated neuroblastoma tumors contain a cellular polypeptide (Mr = 19,000) designated p19, identified in two-dimensional electrophoretic gels, which occurs at significantly higher levels (P = 0.0001) in primary tumors containing amplified N-myc gene. The partial amino acid sequence obtained for p19 is identical to the sequence of the human nm23-H1 protein. An antibody to the A subunit of erythrocyte nucleotide diphosphate kinase reacted exclusively with p19. In this study, significantly higher levels of p19/nm23 occurred in primary neuroblastoma tumors from patients with advanced stages (III and IV) relative to tumors from patients with limited stages (I and II) of the disease. Even among patients with a single copy of the N-myc gene, tumors from patients with stages III and IV had statistically significantly higher levels of p19/nm23 than tumors from patients with stages I and II. Our findings indicate that, in contrast to a proposed role for nm23-H1 as a tumor metastasis suppressor, increased p19/nm23 protein in neuroblastoma is correlated with features of the disease that are associated with aggressive tumors. Therefore, nm23-H1 may have distinct if not opposite roles in different tumors.

Proliferation-related expression of p19/nm23 nucleoside diphosphate kinase.

High level expression of the nm23-H1 gene, which encodes for a nucleoside diphosphate kinase, has been found to correlate with diminished metastasis in some tumors but not in others. We have previously identified the protein product of the nm23-H1 gene in two-dimensional electrophoretic gels and have designated it p19/nm23. In neuroblastoma, higher levels of p19/nm23, which are associated with amplification of the N-myc oncogene, large tumor mass, and metastasis, were observed in advanced stage tumors compared with limited stage disease. Because of the variable expression of nm23-H1 in different tumors, we have investigated the relationship between amounts of the protein and cell proliferation. The levels of p19/nm23 were compared between resting and mitotically stimulated normal human PBLs and in leukemia cells. The amount of p19/nm23 increased in normal lymphocytes in response to mitotic stimulation and paralleled the increase in DNA synthesis. In leukemia cells obtained from patients with different subtypes of acute leukemia, p19/nm23 levels were also increased relative to resting normal lymphocytes. Treatment of mitotically stimulated lymphocytes with cyclosporin, which inhibits proliferation, blocked the increase in p19/nm23; treatment of the leukemia cell line HL-60 with dimethylsulfoxide, which induces terminal differentiation, resulted in diminished levels of p19/nm23. Our data therefore provide evidence that nm23-H1 expression is related to cell proliferative activity.

HSP27 is a mediator of sustained smooth muscle contraction in response to bombesin

We have identified the low MW 27 kD heat shock protein as a major phosphoprotein constituent of smooth muscle and have investigated its potential role in agonist induced smooth muscle contraction. The neuropeptides bombesin and substance P, which are present in neurons of the anorectal region, induce contraction of isolated smooth muscle cells from this region by activating different intracellular pathways. Substance P-induced contraction is 1,4,5-inositol trisphosphate (IP3)/calmodulin dependent, while contraction induced by bombesin is mediated by a protein kinase C (PKC)-dependent pathway. The sustained contraction induced by bombesin or exogenous PKC was blocked by preincubation of cells with monoclonal antibodies to hsp27, while the transient contraction induced by substance P or IP3 was unaffected by the antibodies. Preincubation with isotype matched control antibodies had no inhibitory effect on contraction induced in response to the agents used. These data support a novel role for hsp27 in the non calmodulin mediated sustained contraction induced by bombesin or PKC.

EQUINE BABESIOSIS ASSOCIATED WITH STRENUOUS EXERCISE : CLINICAL AND PATHOLOGICAL STUDIES IN JORDAN

Clinical, haematological and pathological studies were undertaken in Jordan in a stud of 103 racing horses clinically suffering from babesiosis and apparently healthy animals. Out of 47 horses which participated in strenuous exercise, three mares showed sudden onset of immobility and reluctance to move and two mares died. Clinical examination revealed that these five horses (group 1) had fever, anorexia, weakness and severe icterus and, in two mares, haemoglobinuria. Haematological examination revealed that all five horses were heavily parasitized with Babesia equi. This was also found in four horses (group 2) with no evidence of clinical babesiosis. In group 3 (94 horses), neither clinical signs nor B. equi were observed in the blood. The horses in group 1 and 2 recovered after treatment with imidocarb. When the mean values of white blood cell count, red blood cell count, haemoglobin and packed cell volume in group 1 were compared with those for groups 2 and 3, a significant difference was found (P < 0.05). A significant difference was also found when the mean values were compared before and after treatment. Examination of serum total protein, bilirubin and serum enzymes revealed a significant decrease in the mean value of total serum protein (P < 0.05), and a significant increase in the mean values of bilirubin (P < 0.05) in group 1 compared to groups 2 and 3. A significant elevation in the mean value of aspartate aminotransaminase, gamma-glutamyltransferase and creatine phosphokinase and a substantial elevation in the mean value of alkaline phosphatase was also observed in group 1 compared to groups 2 and 3. Postmortem examination of the dead horses showed that the animals had icterus, hepatomegaly and full urinary bladder with deep-red urine. Histopathological examination of the liver showed massive centrilobular degeneration and necrosis. The bile canaliculi and bile ducts were prominent and plugged with dark-brown to canary-coloured bile pigments. The lungs had congestion, oedema, and thrombosis of pulmonary veins. Our results suggest that the horses suffered from B. equal with clinical manifestation following exercise. The clinical, haematological and pathological findings indicate that the animals suffered from haemolytic anaemia which responded to imidocarb therapy.

Involvement of Op18 in cell proliferation

Op18 is a highly conserved major cytosolic phosphoprotein that is expressed at high levels in acute leukemia and in neuroblastoma. In this study we present evidence pointing to a role for Op18 in cellular proliferation. Blocking of Op18 mRNA translation using antisense oligonucleotides delayed entrance of mitotically stimulated normal peripheral blood lymphocytes into the S phase. Moreover treatment of HL-60 promyelocytic leukemia cells with DMSO or PMA which induced terminal differentiation resulted in a decrease in the level of Op18 RNA and protein. Inhibition of lymphoid proliferation with cyclosporin also resulted in reduced Op18 levels.

PREVALENCE OF HYDATIDOSIS IN SLAUGHTERED ANIMALS FROM NORTH JORDAN

The prevalence of hydatid disease was investigated in 704 sheep, 391 goats, 280 cattle and 68 camels slaughtered at two abattoirs in North Jordan. The infection rates for these animals were 4.0, 3.6, 11.4 and 8.8%, respectively. In general, older animals had higher infection rates than younger ones. The percentage of infected animals that had fertile cysts was 66.7% in camels, 34.3% in cattle, 28.6% in goats and 7.1% in sheep. Out of 143 single cysts recovered from cattle, 52.4% were fertile; 29.2% of cysts in goats, 14.7% of cysts in camels and 8.0% of those in sheep were fertile. However, infected sheep had more fertile multiple cysts than other animals. The lung was the predominant location for hydatid cysts in camels. In cattle and goats more hydatid cysts were found in the lung than in the liver, while in sheep the reverse was true.

Quantitative analysis of Op18 phosphorylation in childhood acute leukemia.

Oncoprotein 18 (Op18) is a major cystolic phosphoprotein constituent of leukemia cells. There is cumulative evidence that suggests a role for Op18 in integrating signals from diverse pathways involved in cell growth. Op18 phosphorylation is induced with proliferation in a variety of cell types, and is essential for cell cycle progression. In this study we analyzed the level of unphosphorylated Op18 and of its major phosphorylated forms, Op18a and Op18b, in a series of 177 childhood acute leukemias by means of quantitative two-dimensional polyacrylamide gel electrophoresis (2-D PAGE). Op18 phosphorylation was significantly correlated with the white blood count at the time of diganosis, and with a high percentage of cells in the S phase. Our findings suggest that strategies to inhibit Op18 expression or phosphorylation may be effective in inhibiting leukemia cell proliferation.

Prevalence and pathology of foreign bodies (plastics) in Awassi sheep in Jordan

Abstract The prevalence and associated pathology of foreign bodies in 1453 sheep presented to the Veterinary Clinic during a 27 month period and in the rumen and reticulum from 300 sheep from Amman and Irbid slaughterhouses were studied in Jordan. Of the 1453 sheep, 130 had rumen impaction by plastic and were treated by rumenotomy. The type and location of foreign bodies were examined in 54 out of the 130 sheep. Plastics were the most common (74%), rope and leather were the least common (7%), and all were found in the rumen. Pins and nails were encountered (18.5%) in both rumen and reticulum. Plastic bags were also the most common (78%) foreign bodies found in the rumen of sheep examined in Amman and Irbid from slaughterhouses. In 20 sheep (6.6%), metal masses were found in the rumen. Only in 3 sheep (1%) were pins and nails present in the reticulum. Gross examination of the rumens with plastic revealed areas of sloughing, hemorrhages, congestion and stunting of the papillae. Histopathological examinations revealed areas of coagulative necrosis, hyperemia, inflammatory processes and focal hyperplasia. Several mitotic figures and cells with more than one nucleolus were also present. The results suggest that the plastics in the rumen may play an important role in the pathogenesis of rumenitis. The results, also, suggest that the most common types of foreign bodies in Jordan are plastics and a clean up of the environment would substantially reduce the prevalence of foreign body-pica syndrome in sheep.

Incidence of clinical mastitis and prevalence of subclinical udder infections in Jordanian dairy cattle

Abstract Nineteen Jordanian dairy farms selected by stratified random sample were monitored between July 1991 and August 1992 in order to: (a) determine the incidence of clinical mastitis; (b) assess the influence of season and herd size on the incidence of clinical mastitis; (c)_estimate and identify major udder pathogens and their prevalence. Sixty-five percent of clinical mastitis cases occured between December and April. The incidence of clinical mastitis was 6.8, 5.0 and 3.3 cases per 100 cow-months at risk for herds with 10–29 cows, 30–59 cows, and more than 59 cows, respectively. The most common organisms isolated from clinical cases were coagulase-negative staphylococci (16%) and Staphylococcus aureus (14%). The most prevalent bacterial pathogens in subclinical udder infections were coagulase-negative staphylococci (9.4–11.8%), Staphylococcus aureus (9.2–12.1%) and Corynebacterium bovis (5.8–7.5%). The prevalence rates of Escherichia coli and Enterobacter spp. increased during the winter season for the three herd-size strata.

PCNA levels in neuroblastoma are increased in tumors with an amplified N-myc gene and in metastatic stage tumors

N-myc oncogene amplification in neuroblastoma has been found to be significantly associated with advanced stage disease and tumor progression. However, there is a lack of data on tumors, regarding the relationship between N-myc gene amplification and proliferation activity. Proliferating cell nuclear antigen (PCNA) is a proliferation-induced 36 kD nuclear protein that is the auxiliary component of DNA polymerase δ. PCNA levels in tissues have been found to correlate with proliferative activity. We have examined PCNA levels in neuroblastomas in relation to N-myc gene amplification and tumor stage. Statistically, significantly higher levels of PCNA were observed in tumors with an amplified N-myc gene relative to tumors with a single gene copy. The highest levels of PCNA were observed in advanced stage tumors with an amplified N-myc gene. Treatment of neuroblastoma cells in culture with retinoic acid, which induces differentiation, resulted in a substantial decrease in PCNA. Our results suggest that PCNA levels may reflect differences in proliferative activity between neuroblastomas, related to stage of the disease and to N-myc gene copy number.[/p ]