Human neutrophils contain a protein kinase C-like enzyme that utilizes guanosine triphosphate as a phosphate donor. Cofactor requirements, kinetics, and endogenous acceptor proteins

Investigations of protein kinase C (PKC) activity have focussed on protein phosphorylation using adenosine triphosphate (ATP), not guanosine triphosphate (GTP), as the phosphate donor. In a continuing study of the enzymology of the PKC of human neutrophils, we wanted to determine if there might be protein kinases that do use GTP as a phosphate donor. Soluble extracts or detergent-extracted fractions of human neutrophils were used as enzyme sources. Phosphorylation of histone using [gamma-32P]-GTP was 31% as effective as [gamma-32P]-ATP. Phosphorylation with GTP depended on Ca2+, Mg2+, and phospholipid, just as the ATP, and the Ca2+ requirements were similar. In all cases, H-7, an inhibitor of ATP-supported PKC activity, blocked GTP-utilizing activity. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) revealed that similar endogenous proteins were phosphorylated with ATP or GTP. The apparent Km and Vmax for the enzyme(s) for both phosphate donors were identical, although these were modified by treatment with Triton X-100. GTP competitively inhibited use of ATP by PKC; however, low concentrations of ATP enhanced GTP- utilizing kinase activity in some cases. Non-hydrolyzable forms of ATP and other nucleotide triphosphates were inhibitory. Detergent treatment also markedly altered the number of proteins phosphorylated by either nucleotide. The major protein phosphorylated in the soluble or detergent extract was a single polypeptide band in the 34 Kd range. These studies are the first to explicitly examine the possible phosphorylation by neutrophil PKC using GTP and point to a potential alternative mode of enzyme activity. Since high concentrations of GTP are available within neutrophils, the ability of PKC or a PKC-like enzyme to use this nucleotide may have important ramifications in signal transduction.     

High-risk use of over-the-counter non-steroidal anti-inflammatory drugs: a population-based cross-sectional study

Background

The use of non-steroidal anti-inflammatory drugs (NSAIDs) is associated with serious adverse drug events (ADEs).

Aim

To determine the prevalence of over-the-counter (OTC) NSAID use in the general population and in patients with a high risk of developing a serious NSAID-related ADE.

Design and setting

Cross-sectional study in four general practices in the Netherlands.

Method

Two patient samples were selected: a random sample of adults (general population sample); and adult patients with a high risk of developing a serious ADE in case of NSAID use (high-risk sample). All included patients were sent a questionnaire regarding their use of OTC NSAIDs in the 4 weeks prior to participation.

Results

In the general population sample, 118 of 456 (26%) invited patients completed the questionnaire. Of these, 35 (30%) had used an OTC NSAID. In the high-risk sample, 264 of 713 (37%) invited patients completed the questionnaire, and of these high-risk patients 33 (13%) had used an OTC NSAID. Over 20% of OTC NSAID users in the general population sample and over 30% in the high-risk sample had used the OTC NSAID for >7 days. OTC NSAIDs were used in a dosage exceeding the recommended daily maximum by 9% and 3% of OTC NSAID users in the general population and the high-risk sample respectively.

Conclusion

OTC NSAIDs are used by almost one-third of the general population. In the high-risk patients selected, one in eight patients used an OTC NSAID. Continued efforts by health authorities and healthcare professionals to inform patients of the risks of these drugs are warranted.     

Long-term follow-up of gastric histology after Helicobacter pylori eradication

Helicobacter pylori causes chronic active gastritis and is thought to be associated with the development of gastric atrophy, intestinal metaplasia and carcinoma. As the effect of H. pylori eradication on this process is poorly understood, we sought to determine the long-term effects of H. pylori eradication on gastric histology. Fifty-four patients with duodenal ulceration associated with H. pylori infection received H. pylori eradication therapy in 1985/86 and either remained infected (n= 22) or had the infection eradicated (n= 32); patients were followed up by endoscopy with gastric antral biopsy for 7.1 years (mean). Histopathological analysis of gastric antral mucosa from patients rendered H. pylori-negative revealed a marked decrease in both inflammatory cells within the lamina propria and intraepithelial neutrophils and an increase in epithelial mucinogenesis. Gland atrophy remained unchanged in both H. pylori-positive and -negative patients. When examined for the presence and severity of intestinal metaplasia, there was neither a difference between the two patient groups nor a change with time. These data demonstrate that significant long-term improvements in gastric histology accompany H. pylori eradication when compared with histology in patients with persistent infection. Whether this confers a protective effect by reducing the risk of gastric carcinoma remains unknown.     

Prevalence of asymptomatic malaria parasitaemia

ObjectiveTo evaluate factors associated with prevalence of malaria parasitaemia at first antenatal care visit.MethodsThe study was conducted at the University of Calabar Teaching Hospital from 1st June, 2007 to 31st July, 2007. A structured questionnaire was administered to a total of 545 pregnant women that were recruited in this study after obtaining informed consent and two slides of thin and thick films were prepared for each participant.ResultsFive hundred and twenty (95.4%) out of the 545 participants suffered from malaria parasitaemia, the rest 4.6% of those who had no parasitaemia had experienced symptomatic malaria before and were treated in private hospitals prior to their recruitment into the study. All participants (100%) who did not have antimalarials had parasitaemia compared with 91.1% among those that had antimalarials. The proportion of moderate to severe parasitaemia was also significantly higher among the former. Besides, the difference in parasitaemia between primigravidae and multigravidae was statistically significant (P=0.000) too. Among the methods used for vector control, only insecticide treated nets (ITNS) was associated with significant reduction in the level of parasitaemia (RR =0.83).ConclusionMalaria parasitaemia at first booking is significantly higher in primigravidae and women who have no anti-malaria treatment. The use of safe and effective antimalarial treatment along with ITNs will significantly reduce the level of parasitaemia in pregnant women.     

长期口服小剂量阿司匹林不能预防健康女性患2型糖尿病

慢性无临床症状的炎症与2型糖尿病的发生有关,流行病学资料认为这种关联在妇女表现得更为强烈。虽然小型临床研究显示短期口服大剂量阿司匹林具有明显的降糖效果,但是并没有随机试验直接评估临床可接受的剂量的阿司匹林预防糖尿病的效果。在美国一项随机、双盲、安慰剂-对照的女性健康研究（Women＇s Health Study）中,38716名45岁以上的且无临床糖尿病的健康女性随机口服小剂量的阿司匹林（n=19326）或安慰剂（n=19390）,     

Bladder cancer: staging with CT and MR imaging

Magnetic resonance (MR) imaging and computed tomography (CT) were compared in 30 patients with histologically proved bladder cancer. MR imaging was accurate in depicting the presence or absence of extravesical spread in 22 patients (accuracy, 73%; sensitivity, 82%; specificity, 62%), and CT was accurate in 24 patients (accuracy, 80%; sensitivity, 94%; specificity, 62%). The MR examinations of two patients were of undiagnostic quality and therefore considered to be technical failures. Each technique resulted in five false-positive and one false-negative examination for the diagnosis of extravesical tumor spread. In 28 patients the integrity of the bladder wall was assessed with MR imaging. In 22 patients the bladder wall was disrupted, and 18 of these patients had deep muscle invasion. In six patients the bladder wall was intact, and none of these patients had evidence of deep muscle invasion at pathologic examination. In this study MR imaging was slightly inferior to CT in the delineation of invasive tumors beyond the bladder wall. However, if one excludes from analysis the two patients with undiagnostic studies, there is no significant difference in accuracy between the two techniques.