"Ready, set, go": checkpoint regulation by Cdk1 inhibitory phosphorylation.

ABSTRACT Cell cycle checkpoints prevent mitosis from occurring before DNA replication and repair are completed during S and G2 phases. The checkpoint mechanism involves inhibitory phosphorylation of Cdk1, a conserved kinase that regulates the onset of mitosis. Metazoans have two distinct Cdk1 inhibitory kinases with specialized developmental functions: Wee1 and Myt1. Ayeni et al used transgenic Cdk1 phospho-acceptor mutants to analyze how the distinct biochemical properties of these kinases affected their functions. They concluded from their results that phosphorylation of Cdk1 on Y15 was necessary and sufficient for G2/M checkpoint arrest in imaginal wing discs, whereas phosphorylation on T14 promoted chromosome stability by a different mechanism. A curious relationship was also noted between Y15 inhibitory phosphorylation and T161 activating phosphorylation. These unexpected complexities in Cdk1 inhibitory phosphorylation demonstrate that the checkpoint mechanism is not a simple binary "off/on" switch, but has at least three distinct states: "Ready", to prevent chromosome damage and apoptosis, "Set", for developmentally regulated G2 phase arrest, and "Go", when Cdc25 phosphatases remove inhibitory phosphates to trigger Cdk1 activation at the G2/M transition.

Multiple resistant Pseudomonas aeruginosa in contemporary medical practice: findings from urinary isolates at a Nigerian University Teaching Hospital.

Pseudomonas aeruginosa is a bacterium that is often encountered in urinary tract infection (UTI) worldwide and has shown varied antibiotic susceptibility patterns. This study was therefore designed to ascertain the antibiotic susceptibility patterns of the organism in Jos. Data on antimicrobial susceptibility of P. aeruginosa generated from urine samples by the Microbiology laboratory of Jos University Teaching Hospital (JUTH) was compiled for a period of three years (July 2001-June 2004). Additional information was obtained from the records department of the hospital. Samples were collected, stored and processed using standard laboratory procedures. The rate of isolation of P. aeruginosa from urine samples was found to be 4.6% (n=127) from 12,458 samples. From male population 34% (n=43) were isolated and 66 % (n=84) were recovered from females population with a significant (P < 0.05) gender difference. All the 100 % isolates of P. aeruginosa were resistant to penicillin, cloxacillin, tetracycline, nitrofurantoin and nalidixic acid. while 67% were sensitive to augmentin, sensitivity to ofloxacin was 92%, ciprofloxacin 92% and cefuroxime (86%). The resistance pattern of P. aeruginosa from urine against antibiotics was extremely high. Prophylactic antibiotic medication against UTI should be carefully weighed against this undesirable possible outcome (resistance). Susceptibility testing should be adopted as a basic routine laboratory procedure in hospitals and clinics in order to guide appropriately on the right choice of antibiotics. Finally, ofloxacin, ciprofloxacin, and cefuroxime should be considered on isolation of P. aeruginosa from UTI, especially in the absence of a sensitivity report as well as for prophylactic options.

Nosocomial and community acquired urinary tract infections at a teaching hospital in north central Nigeria: findings from a study of 12,458 urine samples.

BACKGROUND: Urinary tract infection (UTI) is still a problem not infrequently encountered in the course of clinical practice. This study was designed to ascertain its prevalence among both the in and out-patients and the antibiotic susceptibility pattern of the isolates. METHOD: A retrospective analysis of data from all the urine samples processed at Jos university teaching hospital microbiology laboratory was undertaken for a period of 36 months (January 2000-December 2002). Samples had been collected, stored and processed by standard laboratory procedures. Results obtained were analysed using SPSS 11 statistical software and P values < 0.05 were considered significant. RESULTS: Of the 12,458 urine samples studied comprising 43% males and 57% females: the overall prevalence of UTI was found to be 22%; 7.4% among males and a higher figure of 14.6% among females, this was statistically significant (p < 0.05). The rate of nosocomial UTI was significantly higher than the community acquired type: 12.3% and 9.3% respectively (p < 0.05). The commonest nosocomial isolate was Klebsiella spp while Escherichia coli were for community acquired group. Staphylococcus aureus, Coagulase negative Staphylococcus, Proteus spp and Pseudomonas aeruginosa were also common isolates. The most effective antibiotics were Ofloxacin, Ciprofloxacin and Cefuroxime. CONCLUSION: In-patients especially should be encouraged to drink adequate water daily and practice "double urination" to reduce incidence of UTL. Ofloxacin, Ciprofloxacin and Cefuroxime should be considered first in the treatment of UTI in the absence of a susceptibility test.

Bacteriology of urinary tract infection among patients with acquired immunodeficiency syndrome in Jos, Nigeria.

BACKGROUND: The study was set to find out the bacterial agents causing urinary tract infection (UTI) in acquired immunodeficiency syndrome (AIDS) patients. METHODS: Two hundred patients with AIDS on admission at the Jos University Teaching Hospital (JUTH) were recruited into this study. Urine sample was collected from each patient and processed. Other information was obtained with protocol questionnaire. The results were analyzed using Epi Info 6. RESULTS: The prevalence of UTI in AIDS patients was found to be 24% and control 10.6%. Escherichia coli were the commonest Gram-negative isolate followed by Klebsiella species. Enterococcus species was the commonest Gram-positive organism. CONCLUSION: There should be extreme caution whenever the need arises to catheterize AIDS patients.

Antibody levels to Salmonella typhi and paratyphi in Nigerians.

OBJECTIVE: To determine the antibody titre levels to typhoid/paratyphoid fever organisms among apparently healthy volunteers. DESIGN: Cross sectional study. SETTING: General community and University Teaching Hospital. PARTICIPANTS: Volunteer sample of 323 apparently healthy individuals with body temperatures < or = 37.8 degrees C. MAIN OUTCOME MEASURES: Questionnaire administration to classify volunteers into three socio-economic status (SES). RESULTS: There were 35.29% of the apparently healthy population in Jos community with antibodies to typhoid/paratyphoid fever organisms. The presence of these antibodies were neither sex nor SES related. Normal antibody titres were up to 1:40 and 1:80 for O and H Salmonella antigens respectively. Contrary to the general belief, typhoid/paratyphoid fevers have not affected virtually everybody in Nigeria. The difference between those without previous history and those with previous history was significant (p < 0.05) with those in the former category having a higher percentage. CONCLUSION: For a single sero-diagnosis to have any diagnostic value in Jos community and its environs, only a four-fold rise to what has been found to be normal should be significant. This means that only titres of 1:160 and 1:320 and above for O and H antigens should be considered significant.

Pilon fractures of the tibia: a study based on 19 cases.

Twenty-seven pilon fractures of the tibia were identified from 733 adult tibial and ankle fractures admitted to the Coventry and Warwickshire Hospital in 5 years. Nineteen of the 27 were reviewed. The fractures were classified into types I, II and III according to the AO/ASIF system. Treatment was by splintage in plaster-of-Paris or open reduction and internal fixation, and an external fixator for one type III. Non-operative treatment produced good functional results in all type I fractures, poor results in type II and was not applicable to type III. Eight of 11 types II and III fractures, treated by internal fixation achieved good functional results. Hindfoot disability was assessed from subtalar movements. It is concluded that open reduction and internal fixation is indicated in types II and III pilon fractures. Subtalar motion is negligibly restricted in type I fractures, while in types II and III internal fixation is followed by recovery of hindfoot function.

The prevalence of gastro-intestinal parasites and bacteria in the game scouts at the Kainji Lake National Park of Nigeria.

The faeces of twenty scouts working at Borgu games were examined for the presence of parasites and bacteria. Cysts of Entamoeba histolytica, Giardia lamblia and Trichomonas hominis were found. Helminth ova encountered included those of Ancylostoma duodenale, Ascaris lumbricoides, Stronglyloides stercoralis and Trichuris trichiura. Escherichia coli and Shigella flexneri were isolated from one faecal sample each. In all, parasites were found in the faeces of only 9 scouts. The epidemiological significance of the infections in highlighted.

Parasitic infections of the grey-breasted helmet guinea-fowl (Numida meleagris galeata) in Nigeria.

The major helminth parasites found in wild, semi-wild and golden Sovereign stock guinea fowl were Heterakis gallinarum, Ascaridia galli, Capillaria caudinflata, Raillietina tetragona and R. echinobothrida, while Eimeria species was the most important gastro-intestinal protozoan parasite. The incidence of the latter was higher in the semi-wild stock than in the wild stock. Necropsy of dead guinea-fowl indicated that A. galli, H. gallinarum and Eimeria species were indeed responsible for their deaths, especially in the young birds. Parasites found in blood smears were Leucocytozoon sp., Plasmodium sp. and Aegyptianella pullorum. The only tick found, Argas persicus, was on a few semi-wild stock, while lice of genus Damalinia were found only on wild birds.

The seminiferous epithelium in the guinea fowl (Numida meleagris).

Spermiogenesis and cellular associations in the seminiferous epithelium of the guinea fowl were studied and described in "sexually" active adult birds. PAS stain was found to be useful in the recognition of steps of spermatid differentiation only in the first early stages. Nuclear morphological changes were subsequently found to be more reliable in tracing steps of spermiogenesis. It was observed that haematoxylin-eosin stained tissue can be used in the study of spermiogenesis in the bird. Various stages of the seminiferous epithelium were observed in any cross-section of the seminiferous tubules. Distinct cellular associations were observed, but intermix of adjacent germ cells or heterogenous cellular associations were frequently encountered.

The structure of the excurrent ducts of the testis of the guinea-fowl (Numida meleagris).

The epididymal region of the guinea-fowl was studied in sexually mature birds. The structure of the epididymal region was generally similar to that already described for the domestic fowl, turkey and Japanese quail. Well formed, intratesticular tubuli recti was seen connecting the seminiferous tubules with the rete testis. The latter consists of both intracapsular and extracapsular portions. Six main cell types were recognised in the region: the rete testis was lined by squamous cells, the proximal efferent ductules by ciliated and non-ciliated Type I cells, the distal efferent ductule by ciliated and non-ciliated Type II cells, and the connecting ductules, ductus epididymidis and ductus deferens were lined by non-ciliated Type III and basal cells. The cell classification adopted in this study is discussed.