Associations between serum health biomarker concentrations and reproductive performance, accounting for milk yield, in pasture-based Holstein cows in southeastern Australia.

In this single cohort study, we investigated associations between the concentrations of a suite of serum biomarkers measured in the first 30 d of lactation and subsequent reproductive performance measured as mating start date to conception intervals, in pasture-based Holstein cows. A secondary objective was to examine associations between biomarker concentrations and 305-d milk yield to assess whether any positive associations between biomarker concentration and reproductive performance were explained by reduced milk production. The data used had been collected as part of an ongoing project from 2017 to 2020 to compile a data set from a large population of lactating dairy cows. Biomarkers measured were those associated with energy balance (ß-hydroxybutyrate [BHB] and nonesterified fatty acids [NEFA]), protein nutritional status (urea and albumin), immune status (globulin, albumin to globulin ratio and haptoglobin), and macromineral status (calcium and magnesium). Associations between biomarker concentrations and mating start date to conception interval were investigated using Cox proportional hazard models, using between 634 and 1,121 lactations (varying by biomarker) from 632 to 1,103 cows and 11 to 17 mating periods from 10 to 13 herds. Based on hazard ratio (HR) estimates and associated 95% confidence intervals (CI), hazard of conception on any particular day of the herds' mating periods was positively associated with the concentrations of albumin (HR = 1.09; 95% CI: 1.05-1.12), albumin to globulin ratio (HR = 2.82; 95% CI: 1.66-4.79), calcium (HR = 2.01; 95% CI: 1.18-3.43), and magnesium (HR = 2.17; 95% CI: 1.01-4.66), and negatively associated with globulin concentration (HR = 0.98; 95% CI: 0.97 to 1.00). There was also some evidence that NEFA concentration was negatively associated (HR = 0.76; 95% CI: 0.57 to 1.01), and urea concentration positively associated (HR = 1.05; 95% CI: 0.99 to 1.11), with reproductive performance, but no evidence that BHB and haptoglobin concentrations were associated with reproductive performance. Except for NEFA, presence and direction of the associations between the biomarker and milk yield were not discordant with that for reproductive performance. Also, except for NEFA, we found no substantial evidence of nonlinear relationships between biomarker concentration and either reproductive performance or milk yield. Correlations between biomarker concentrations were generally weak, indicating that multibiomarker panels may collectively predict reproductive performance better than any single biomarker. We noted substantial variation in the concentrations of all biomarkers within, and for some biomarkers, between herd-year groups. Collectively, these results indicate that there may be scope to improve biomarker concentrations through nutritional, management, and genetic interventions, and by association, reproductive performance and milk yield may also improve.

Milk production of cows grazing pasture supplemented with grain mixes containing canola meal or corn grain or both over the first 100 days of lactation.

Grain mixes varying in proportions of wheat grain, barley grain, canola meal, and corn grain were fed to grazing dairy cows in early lactation to determine the contribution of canola meal and corn grain to milk yield, BW, BCS, eating behavior, and blood serum metabolite concentrations. The experiment used 80 multiparous, seasonally calving Holstein-Friesian dairy cows during the first 100 d of lactation, the treatment period, and over the subsequent carryover period of 100 d, during which all cows were fed a common diet. Cows were divided into 4 cohorts (blocks) based on calving date and within each cohort, 5 cows were randomly allocated to each of the 4 treatments. Dietary treatments included disc-milled grain mixes comprising (on a DM basis) (1) a control treatment of wheat (25%) and barley (75%); (2) wheat (25%), barley (50%), and canola meal (25%); (3) wheat (25%), barley (50%), and corn (25%), and (4) wheat (25%), barley (25%), canola meal (25%), and corn (25%). Treatment diets were introduced at 19 DIM ± 4.7 d, which included a 7-d adaptation period and were applied up until 100 DIM. Each grain mix was fed at 9 kg of DM/cow per day, offered twice daily, in equal proportions in the parlor at milking times. In addition to the grain mix, all cows grazed perennial ryegrass pasture at a daily allowance of ∼35 kg of DM/cow per day (measured to ground level). Results were analyzed in terms of corn and canola presence or absence in the diet. Including canola meal in grain mixes increased grain intake and pasture intake by 0.6 and 2.1 kg of DM/cow per day, respectively, resulting in an increased milk yield of 2.6 kg/cow per day during the first 100 d of lactation. Including canola meal also increased yields of milk fat and protein, and concentrations of milk fat, as well as increasing mean BW and BCS over the 100 d. The inclusion of canola meal in the grain mixes also resulted in greater blood serum BHB and urea concentrations, compared with feeding grain mixes that did not contain canola meal. The inclusion of corn grain provided no milk production benefits and did not change BW, BCS, or any feeding behavior variables. There were no carryover effects on milk production from either canola meal or corn grain after the treatment period. In summary, the results demonstrate that the provision of canola meal in grain mixes can improve milk production and increase mean BCS. Further, there are no benefits to milk yield when a proportion of barley is substituted for corn, in a wheat and barley grain mix fed to grazing dairy cows in early lactation. However, these results are dependent on the level of inclusion and the feeding system employed.

Macroprolactin screening in 464 patients with hyperprolactinaemia.

INTRODUCTION: Macroprolactinaemia is usually detected by polyethylene glycol (PEG) precipitation in clinical laboratories. Laboratory data on prolactin and macroprolactin screening by PEG precipitation in a tertiary hospital were reviewed in order to revise the local policy for reflex screening and reporting of macroprolactin in patients with hyperprolactinaemia. MATERIALS AND METHODS: Paired prolactin results from 464 patients before and after PEG precipitation, either requested by a clinician or performed as a reflex test, were retrieved and reviewed. RESULTS: Recovery of prolactin after PEG treatment was highly variable (3.7 to 97.7%). The distribution of prolactin recovery percentages after PEG precipitation in patients with true hyperprolactinaemia was markedly different from that in patients without true hyperprolactinaemia. The proportion of patients with true hyperprolactinaemia increased gradually with increasing pre-PEG prolactin concentrations; the reverse was true with macroprolactinaemia. Five patients (1.1%) were found to have co-existing macroprolactinaemia and true hyperprolactinaemia. CONCLUSION: Results from this retrospective study indicate that macroprolactinaemia is common and can be present even in patients with very high serum prolactin concentrations. There is no cut-off limit for pre-PEG serum prolactin concentration that can totally exclude macroprolactinaemia. Moreover, co-existence of true hyperprolactinaemia and macroprolactinaemia in the same patient is not a rare phenomenon. Post-PEG prolactin concentration and percentage recovery should be reported together to guide the interpretation and management of hyperprolactinaemia.

Obstructed jejunal duplication cyst in an infant.

Intestinal obstruction in infancy due to duplication cyst is rare. This is a case of a three-month old boy presented to the hospital with symptoms and signs of intermittent intestinal obstruction for three-week duration. Investigation with ultrasound revealed a small bowel duplication cyst. Patient underwent successful segmental jejunal resection and made an uneventful recovery. He made significant weight gain at one-year follow-up. The diagnostic approach to infant with intestinal obstruction is described with special emphasis on ultrasonographic features of jejunal duplication cyst.

Expression of DNA damage response proteins in cervical cancer patients treated with radical chemoradiotherapy.

OBJECTIVE: The management of locally advanced cervical cancer has improved significantly with the advent of cisplatin-based chemoradiotherapy (CRT) as the primary treatment regimen. Nevertheless, a significant proportion of patients fail to respond or relapse on this treatment and have a very poor prognosis. Our goal was to determine the prognostic value of a panel of proteins involved in detection and repair of DNA damage. METHODS: We performed fluorescence immunohistochemistry, and used software analysis to assess expression of DNA damage response proteins ATM, DNA-PKcs, PARP-1, Ku70 and Ku86 in 117 pre-treatment specimens from patients with locally advanced cervical cancer. We compared expression to clinicopathologic correlates to determine prognostic significance. RESULTS: Five-year progression-free survival was significantly lower in the low expressors than in high expressors of ATM (35% vs. 58%, p=0.044) and PARP-1 (24% vs. 61%, p=0.003), and showed a trend to significance for DNA-PKcs (30% vs. 60%, p=0.050). Low expression of the same proteins also correlated significantly with lower overall survival. In multivariable analysis, adjusted for FIGO stage and tumor size, low ATM and PARP-1 expression was significantly associated with both poorer progression-free and overall survival. Pairwise analyses indicated that expression levels of these proteins were correlated. CONCLUSIONS: Expression of DNA damage response proteins in cervical cancer is associated with outcome in patients treated with CRT. Immunohistochemical analysis of these proteins may be useful in guiding treatment decisions in such patients.

Adjuvant hepatic intra-arterial iodine-131-lipiodol following curative resection of hepatocellular carcinoma: a prospective randomized trial.

BACKGROUND: The purpose of the present study was to determine whether intrahepatic injection of (131)I-lipiodol (Lipiodol) is effective against recurrence of surgically resected hepatocellular carcinoma (HCC). METHODS: From June 2001 through March 2007, this nationwide multi-center prospective randomized controlled trial enrolled 103 patients 4-6 weeks after curative resection of HCC with complete recovery (52: Lipiodol, 51: Control). Follow-up was every 3 months for 1 year, then every 6 months. Primary and secondary endpoints were recurrence-free survival (RFS) and overall survival (OS), respectively, both of which were evaluated by the Kaplan-Meier technique and summarized by the hazard ratio (HR). The design was based on information obtained from a similar trial that had been conducted in Hong Kong. RESULTS: The Lipiodol group showed a small, and nonsignificant, improvement over control in RFS (HR = 0.75; 95 % confidence interval [95 % CI] 0.46-1.23; p = 0.25) and OS (HR = 0.88; 95 % CI 0.51-1.51; p = 0.64). Only two serious adverse events were reported, both with hypothyroidism caused by (131)I-lipiodol and hepatic artery dissection during angiography. CONCLUSIONS: The randomized trial provides insufficient evidence to recommend the routine use of (131)I-lipiodol in these patients.

Is pancreaticoduodenectomy justified in elderly patients?

BACKGROUND: Although mortality & morbidity for pancreaticoduodenectomy (PD) have improved significantly over the last two decades, the concern for elderly undergoing PD remains. This study examines the outcome of the elderly patients who had pancreaticoduodenectomy in our institution. METHODS: A prospective database comprising 69 patients who underwent pancreaticoduodenectomy between 2001 and May 2008 was analyzed. Using WHO definition, elderly patient is defined as age 65 and above in this study. Two groups of patients were compared [Group 1: Age ≤65 & Group 2: Age >65]. RESULTS: The mean age of our patients was 62 ± 11 years. There were 37 (54%) patients in Group 1 and 32 (46%) patients in Group 2. There was no statistical difference between the two groups in terms of gender and race. However, there were more patients in the Group 2 with >2 comorbidities (p = 0.03). The median duration of operation was significantly longer in Group 2 (550 min vs 471 min, p = 0.04). Morbidity rate in Group 2 was higher (56% vs. 44%, p = 0.04). There was higher proportion of post-operative pancreatic fistula (POPF) in the elderly group (37.5% vs. 16.7%, p = 0.05). Majority of them are Grade A POPF according to the ISG definition. The median post-operative length-of-stay (LOS) in hospital was 9 days longer in Group 2 (p = 0.01). Mortality rate between the 2 groups of patients was comparable (0% vs. 3%, p = 0.28). CONCLUSION: Elderly patients are at increased risk of morbidity in pancreatocoduodenectomy, in particular POPF. However, morbidity and mortality rates are acceptable. It is therefore justified to offer PD to elderly patients who do not have significant cardiopulmonary comorbidities.

Genetic mutations in patients with possible familial hypercholesterolaemia in South East Scotland.

Familial hypercholesterolaemia (FH) is one of the most common genetic disorders in the general population. Genetic testing of this condition is increasingly available in the UK to confirm its diagnosis, but the strategies of genetic testing vary. In this pilot study, we sought to investigate whether a strategy that focuses on the low-density lipoprotein receptor (LDLR) and apolipoprotein B (APOB) genes can identify the majority of genetic variants in patients with possible FH in South East Scotland. Forty patients with a clinical diagnosis of possible FH according to the Simon Broome criteria were recruited in a lipid clinic serving South East Scotland. All 18 exons of the LDLR gene were sequenced and multiplex ligation probe amplification was performed to identify major deletions and duplications. Variants of the APOB gene at codon 3527 were investigated by direct sequencing. Genetic mutations were detected in 45% of the patients. Sixteen patients (40%) were found to have mutations in their LDLR gene, whereas two other patients (5%) were identified as heterozygous for the APOB variant commonly associated with FH (c.10580G>A; p.R3527Q). None of these genetic variants were detected in more than two patients. Multiple genetic mutations are associated with a clinical phenotype of FH in South East Scotland. A genetic testing strategy which focuses on a limited number of mutations is unlikely to confirm the diagnosis of FH in the majority of patients in this part of Scotland.

Latitudinal variation in top-down and bottom-up control of a salt marsh food web.

The shrub Iva frutescens, which occupies the terrestrial border of U.S. Atlantic Coast salt marshes, supports a food web that varies strongly across latitude. We tested whether latitudinal variation in plant quality (higher at high latitudes), consumption by omnivores (a crab, present only at low latitudes), consumption by mesopredators (ladybugs, present at all latitudes), or the life history stage of an herbivorous beetle could explain continental-scale field patterns of herbivore density. In a mesocosm experiment, crabs exerted strong top-down control on herbivorous beetles, ladybugs exerted strong top-down control on aphids, and both predators benefited plants through trophic cascades. Latitude of plant origin had no effect on consumers. Herbivorous beetle density was greater if mesocosms were stocked with beetle adults rather than larvae, and aphid densities were reduced in the "adult beetle" treatment. Treatment combinations representing high and low latitudes produced patterns of herbivore density similar to those in the field. We conclude that latitudinal variation in plant quality is less important than latitudinal variation in top consumers and competition in mediating food web structure. Climate may also play a strong role in structuring high-latitude salt marshes by limiting the number of herbivore generations per growing season and causing high overwintering mortality.

Using percutaneous transhepatic cholangioscopic lithotripsy for intrahepatic calculus in hostile abdomen.

BACKGROUND: Hepatolithiasis is a challenging condition to treat especially in patients with previous hepatobiliary surgery. Percutaneous Transhepatic Cholangioscopic Lithotripsy (PTCSL) is an attractive salvage option for the treatment of recurrent hepatolithiasis. We reviewed our experience using PTCSL in treating 4 patients with previous complex abdominal surgery. METHODS: We studied the 4 patients who underwent PTCSL from October 2007 to July 2009. We reviewed the operative procedures, workflow of performing PTCSL in our institution and the outcome of the procedure. PTCSL was performed in our institution using 3 mm cholangioscope (Dornier MedTech(®)) and Holmium laser with setting at 0.8 J, 20 Hz and 16 W. This was performed through a Percutaneous Transhepatic Cholangio-catheter inserted by interventional radiologists. RESULTS: There were 4 patients with a median age of 50 (43-69) years. The median duration of the condition prior to PTCSL was 102 (60-156) months. Three patients had recurrent pyogenic cholangitis (RPC) with recurrent intrahepatic stone. They all had prior complex hepatobiliary operations. The median duration of surgery was 130 (125-180) min. There was minimal intra-operative blood loss. The first procedure was performed under local anaesthesia and sedation, however, with experience the subsequent 3 patients had the procedure performed under general anaesthesia. The median size of bile duct was 18 (15-20) mm prior to the procedure. The number of stones ranged from one to three with the largest size of stone comparable to the size of bile duct. The median follow up was 18 (10-24) months. All patients were symptom free with neither stone recurrence or cholangitis at the last follow up. CONCLUSION: PTCSL is a feasible and an effective treatment method for patients with recurrent biliary stone following complex abdominal surgery as the success rates from open surgery and endoscopic procedures are limited. Excellent results can be expected with this minimally invasive technique.

Abnormal liver function test results are related to metabolic syndrome and BMI in Taiwanese adults without chronic hepatitis B or C.

BACKGROUND: Metabolic syndrome (MS) is considered a cause of abnormal deposition of fat into hepatocytes, which might be associated with hepatic steatosis or abnormal liver function. OBJECTIVE: The aim of this study was to explore the factors associated with MS and the relationship between MS and abnormal aspartate aminotransferase (AST), alanine aminotransferase (ALT) and gamma-glutamyl transferase (GGT) levels in Taiwanese subjects without chronic hepatitis B (CHB) or C (CHC). SUBJECTS: We enrolled 2539 Taiwanese adults without CHB or CHC (age range: 16-88 years old) and investigated the factors related to MS using the NCEP-ATP (National Cholesterol Education Program-Adult Treatment Panel) III criteria; body mass index (BMI) was measured using Asia-Pacific criteria. RESULTS: The prevalence rate of MS in Taiwanese adults without CHB or CHC was 16.9% using the modified ATP III criteria and 15.4% using the International Diabetes Federation criteria. Males had a significantly higher prevalence rate than females (P<0.001), and subjects with MS were significantly older and had significantly higher BMI values and AST, ALT and GGT levels (all P<0.001). In univariate analyses, the abnormality of liver function test results were related to gender, level of fasting sugar, systolic blood pressure, triglyceride, high-density lipoprotein, BMI and MS (all P<0.05). Multivariate analysis showed that the male gender, a higher BMI value and MS were related to abnormal liver function test results. The cutoff value for ALT in relation to MS is 31 IU l(-1) for male and 18 IU l(-1) for female. CONCLUSION: The prevalence of MS in Taiwanese adults without hepatitis B or C was found to be high, and MS and BMI were identified as being related to abnormal liver function test results in these adults.

Evaluation of reflection and refraction in simulations of ultraviolet disinfection using the discrete ordinates radiation model.

Simulations of UV disinfection systems require accurate models of UV radiation within the reactor. Processes such as reflection and refraction at surfaces within the reactor can impact the intensity of the simulated radiation field, which in turn impacts the simulated dose and performance of the UV reactor. This paper describes a detailed discrete ordinates radiation model and comparisons to a test that recorded the UV radiation distribution around a low pressure UV lamp in a water-filled chamber with a UV transmittance of 88%. The effects of reflection and refraction at the quartz sleeve were investigated, along with the impact of wall reflection from the interior surfaces of the chamber. Results showed that the inclusion of wall reflection improved matches between predicted and measured values of incident radiation throughout the chamber. The difference between simulations with and without reflection ranged from several percent near the lamp to nearly 40% further away from the lamp. Neglecting reflection and refraction at the quartz sleeve increased the simulated radiation near the lamp and reduced the simulated radiation further away from the lamp. However, the distribution and trends in the simulated radiation field both with and without the effects of reflection and refraction at the quartz sleeve were consistent with the measured data distributions.

Monocyte chemotactic protein-1 in the migration of differentiated leukaemic cells toward alveolar epithelial cells.

All-trans retinoic acid (ATRA) can induce acute respiratory distress syndrome in patients with acute promyelocytic leukaemia (APL). The current study investigated the role of monocyte chemotactic protein (MCP)-1 in the chemotactic transmigration of ATRA-treated NB4 (ATRA-NB4) APL cells toward A549 alveolar epithelial cells. NB4 and A549 cells were separately cultured with ATRA and/or dexamethasone (DEX). ATRA-NB4 cells were then placed in an upper insert and co-incubated with A549 cells or their conditioned medium (CM) located in a lower plate to test their transmigration activity. ATRA stimulated NB4 cells to transmigrate toward the A549 cells. The secretion of MCP-1 was enhanced by ATRA treatment in both A549 and NB4 cells. The binding assay demonstrated that ATRA-NB4 cells bound MCP-1. Pre-treatment of both CM-A549 cells with antibodies against MCP-1 and of ATRA-NB4 cells with antibodies against MCP-1 receptors reduced ATRA-NB4 cell transmigration. DEX did not suppress MCP-1 secretion and transmigration in ATRA-NB4 cells, although when applied to A549 cells, MCP-1 secretion was suppressed and ATRA-NB4 cell transmigration was attenuated. Monocyte chemotactic protein-1 secreted from alveolar epithelial cells plays an important role in the cell-cell interaction involved in the chemotactic transmigration of all-trans retinoic acid-treated acute promyelocytic leukaemia cells toward alveolar epithelial cells.

Narcolepsy in Southern Chinese patients: clinical characteristics, HLA typing and seasonality of birth.

OBJECTIVE: To report clinical characteristics, human leukocyte antigen (HLA) typing and seasonality of birth of a series of 54 Southern Chinese patients suffering from narcolepsy. METHODS: All subjects underwent detailed medical and psychiatric interviews and a standardised nocturnal polysomnogram followed by a daytime Multiple Sleep Latency Test. Each subject also completed a set of sleep questionnaires. HLA typing was performed in 91% of subjects. RESULTS: A total of 78% and 22% of patients were diagnosed with suffering from cataplectic and non-cataplectic narcolepsy, respectively. The majority (n = 47, 87%) of patients were referred to our sleep clinic for excessive daytime sleepiness (EDS). The cataplectic narcolepsy differed from non-cataplectic narcolepsy by having more rapid eye movement (REM)-related clinical symptoms (more sleep paralysis and sleep-related hallucination) and sleep disturbances (shorter REM latency), as well as tighter association with HLA DQB1*0602. A bi-modal peak pattern was observed at 11 and 39 years old. A similar bi-modal pattern also occurred for EDS and cataplexy. Excess winter births were observed for this series of patients. 81% of patients with cataplectic narcolepsy were DQB1*0602-positive. There were no differences between early- and late-onset cases in the association with positive DQB1*0602 (71.4% vs 60%). Narcolepsy had prominent pernicious effects on various social, academic, family and mental aspects in our patients. CONCLUSIONS: In our Southern Chinese narcolepsy series, bi-modal peak pattern of age of onset, excess winter birth and tight association of HLA DQB1*0602 with cataplectic narcolepsy were found.

The familial risk and HLA susceptibility among narcolepsy patients in Hong Kong Chinese.

STUDY OBJECTIVES: To explore the familial aggregation and HLA susceptibility of narcolepsy in Hong Kong Chinese by objective sleep measurements and HLA typing. DESIGN: Case control design PARTICIPANTS: Twelve narcoleptic probands, 34 first-degree relatives, and 30 healthy controls. INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: Each subject underwent a standardized nocturnal polysomnogram (PSG), followed by a daytime multiple sleep latency test (MSLT). HLA typing was performed for all subjects. One relative (2.9%) was diagnosed as suffering from narcolepsy with cataplexy. Nearly 30% of the relatives fulfilled the criteria of narcolepsy spectrum disorder (shortened mean sleep latency [MSL] and/or the presence of sleep onset REM periods [SOREMPs]). When using the population data for comparison, the relative risk of narcolepsy in first-degree relatives was 85.3. The odds ratio of narcolepsy spectrum disorder in first-degree relatives was 5.8 (95% CI: 1.2 - 29.3) when compared to healthy controls. There existed 6 multiplex families, in which all 10 relatives with narcolepsy spectrum disorders, including all 3 relatives with multiple SOREMPs, were positive for HLA DQB1*0602. CONCLUSIONS: Our study demonstrated a definitive familial aggregation of narcolepsy, narcolepsy spectrum disorders, and possibly cataplexy in Hong Kong Chinese. This familial aggregation supported an inherited basis for narcolepsy spectrum. The tight co-segregation of HLA DQB1*0602 and narcolepsy spectrum disorders might suggest that HLA typing, especially DQB1*0602, at least partly confer the familial risk of narcolepsy. In addition, our study suggested that the subjective questionnaire measurements including Ullanlinna Narcolepsy Scale and Epworth Sleepiness Scale were unable to detect the presence of narcolepsy spectrum disorders among the relatives. A stringent objective measurement-based design for family studies is suggested for future study. Further studies are indicated for the determination of the mode and molecular level of narcolepsy transmission.

Genetic, physical, and functional interactions between the triphosphatase and guanylyltransferase components of the yeast mRNA capping apparatus.

We have characterized an essential Saccharomyces cerevisiae gene, CES5, that when present in high copy, suppresses the temperature-sensitive growth defect caused by the ceg1-25 mutation of the yeast mRNA guanylyltransferase (capping enzyme). CES5 is identical to CET1, which encodes the RNA triphosphatase component of the yeast capping apparatus. Purified recombinant Cet1 catalyzes hydrolysis of the gamma phosphate of triphosphate-terminated RNA at a rate of 1 s-1. Cet1 is a monomer in solution; it binds with recombinant Ceg1 in vitro to form a Cet1-Ceg1 heterodimer. The interaction of Cet1 with Ceg1 elicits >10-fold stimulation of the guanylyltransferase activity of Ceg1. This stimulation is the result of increased affinity for the GTP substrate. A truncated protein, Cet1(201-549), has RNA triphosphatase activity, heterodimerizes with and stimulates Ceg1 in vitro, and suffices when expressed in single copy for cell growth in vivo. The more extensively truncated derivative Cet1(246-549) also has RNA triphosphatase activity but fails to stimulate Ceg1 in vitro and is lethal when expressed in single copy in vivo. These data suggest that the Cet1-Ceg1 interaction is essential but do not resolve whether the triphosphatase activity is also necessary. The mammalian capping enzyme Mce1 (a bifunctional triphosphatase-guanylyltransferase) substitutes for Cet1 in vivo. A mutation of the triphosphatase active-site cysteine of Mce1 is lethal. Hence, an RNA triphosphatase activity is essential for eukaryotic cell growth. This work highlights the potential for regulating mRNA cap formation through protein-protein interactions.

Incidence of neonatal chlamydial conjunctivitis and its association with nasopharyngeal colonisation in a Hong Kong hospital, assessed by polymerase chain reaction.

OBJECTIVES: Using polymerase chain reactions, this study aimed to evaluate the incidence of neonatal chlamydial conjunctivitis in our region of Hong Kong and explore any association between such conjunctivitis and nasopharyngeal colonisation with Chlamydia trachomatis. DESIGN: Prospective epidemiological study. SETTING: Regional hospital, Hong Kong. PATIENTS: Consecutive patients with neonatal conjunctivitis presenting to our hospital were recruited from May 2004 to April 2005 inclusive. Both eyes were investigated separately for Chlamydia trachomatis by polymerase chain reaction, direct immunofluorescent assay, and cell culture by two assigned ophthalmologists. Neonates diagnosed to have ocular Chlamydia trachomatis infection were subjected to additional nasopharyngeal investigations. Complete sets of ocular and nasopharyngeal investigations were also undertaken 1 week after oral erythromycin treatment to confirm complete eradication of Chlamydia trachomatis. RESULTS: Of 192 patients with neonatal conjunctivitis, 24 were diagnosed to have chlamydial conjunctivitis. Fifteen of them had nasopharyngeal colonisation with Chlamydia trachomatis. Among the 20 neonatal chlamydial conjunctivitis patients that completed the follow-up study, one suffered treatment failure. None had clinically diagnosed systemic Chlamydia trachomatis infection 3 months after oral erythromycin. CONCLUSIONS: The incidence of neonatal chlamydial conjunctivitis in our region of Hong Kong was 4 in 1000 live births, of whom 63% had nasopharyngeal presence of Chlamydia trachomatis. Owing to the high rate of nasopharyngeal isolation and possibility of treatment failure, post-treatment ocular and nasopharyngeal polymerase chain reaction testing for Chlamydia trachomatis may be considered to confirm complete eradication.

Mutational analysis of Escherichia coli DNA ligase identifies amino acids required for nick-ligation in vitro and for in vivo complementation of the growth of yeast cells deleted for CDC9 and LIG4.

We report that the NAD-dependent Escherichia coli DNA ligase can support the growth of Saccharomyces cerevisiae strains deleted singly for CDC9 or doubly for CDC9 plus LIG4. Alanine-scanning mutagenesis of E.coli DNA ligase led to the identification of seven amino acids (Lys115, Asp117, Asp285, Lys314, Cys408, Cys411 and Cys432) that are essential for nick-joining in vitro and for in vivo complementation in yeast. The K314A mutation uniquely resulted in accumulation of the DNA-adenylate intermediate. Alanine substitutions at five other positions (Glu113, Tyr225, Gln318, Glu319 and Cys426) did not affect in vivo complementation and had either no effect or only a modest effect on nick-joining in vitro. The E113A and Y225A mutations increased the apparent K (m)for NAD (to 45 and 76 microM, respectively) over that of the wild-type E. coli ligase (3 microM). These results are discussed in light of available structural data on the adenylylation domains of ATP- and NAD-dependent ligases. We observed that yeast cells containing only the 298-amino acid Chlorella virus DNA ligase (a 'minimal' eukaryotic ATP-dependent ligase consisting only of the catalytic core domain) are relatively proficient in the repair of DNA damage induced by UV irradiation or treatment with MMS, whereas cells containing only E.coli ligase are defective in DNA repair. This suggests that the structural domains unique to yeast Cdc9p are not essential for mitotic growth, but may facilitate DNA repair.

An essential surface motif (WAQKW) of yeast RNA triphosphatase mediates formation of the mRNA capping enzyme complex with RNA guanylyltransferase.

Saccharomyces cerevisiae RNA triphosphatase (Cet1p) and RNA guanylyltransferase (Ceg1p) interact in vivo and in vitro to form a bifunctional mRNA capping enzyme complex. Cet1p binding to Ceg1p stimulates the guanylyltransferase activity of Ceg1p. Here we localize the guanylyltransferase-binding and guanylyltransferase-stimulation functions of Cet1p to a 21-amino acid segment from residues 239 to 259. The guanylyltransferase-binding domain is located on the protein surface, as gauged by protease sensitivity, and is conserved in the Candida albicans RNA triphosphatase CaCet1p. Alanine-cluster mutations of a WAQKW motif within this segment abolish guanylyltransferase-binding in vitro and Cet1p function in vivo, but do not affect the triphosphatase activity of Cet1p. Proteolytic footprinting experiments provide physical evidence that Cet1p interacts with the C-terminal domain of Ceg1p. Trypsin-sensitive sites of Ceg1p that are shielded from proteolysis when Ceg1p is bound to Cet1p are located between nucleotidyl transferase motifs V and VI.

Epidemiology of leprosy and response to treatment in Hong Kong.

OBJECTIVES: To review the reported trend of leprosy in Hong Kong. DESIGN: Retrospective study. SETTING: Three major leprosy clinics in Hong Kong. PATIENTS: Leprosy patients registered between 1970 and 2004. MAIN OUTCOME MEASURES: Incidence, rate of deformities, distribution of leprosy subtypes, age distribution, and relapses after therapy. RESULTS: The incidence of leprosy has decreased from 3.2 per 100,000 population in 1970 to 0.088 per 100,000 population in 2004. The proportion of the three subtypes of leprosy has remained roughly equal. There have been 87 relapses within this period with 54 (62%) cases of lepromatous leprosy, 22 (25%) borderline leprosy, and 11 (13%) tuberculoid leprosy. The overall relapse rate was 6.7% (0.2 per 100 person-years); this can be subdivided as a relapse rate for multidrug therapy of 3.2% (0.33 per 100 person-years) and for dapsone monotherapy of 8.3% (0.2 per 100 person-years). The mean interval to relapse for multidrug therapy and dapsone monotherapy was 1.83 and 5.8 years, respectively. The mean duration till relapse for patients on dapsone monotherapy was 15.6 years. CONCLUSION: Treatment with recommended WHO-multidrug therapy is effective and well tolerated. Dapsone monotherapy is no longer effective. Leprosy is well controlled in Hong Kong but continued surveillance is required to detect relapses and to ensure good patient compliance with treatment.