Comparison of four methods of assessing root surface debridement

BACKGROUND

While there is great interest in measuring the efficacy of root surface debridement, there is little consensus on how this might be best achieved. The aim of this study was therefore to compare four different methods of assessing root surface debridement in their ability to discriminate between ultrasonically instrumented root surfaces and non-instrumented control surfaces.

METHODS

Single-session subgingival root debridement was performed by an experienced operator on 30 teeth prior to their extraction. Following extraction, efficacy of root surface debridement was measured by percentage of remaining calculus, instrument efficiency, modified instrument efficiency, and percentage apical plaque border. In addition, the effect of probing depth landmark (apical plaque border versus connective tissue attachment) on outcomes was assessed.

RESULTS

The results indicated that percentage apical plaque border demonstrated highly statistically significant differences between instrumented and control surfaces (P= 0.02). No other assessment method was able to discriminate between instrumented and non-instrumented surfaces, and this may be a function of the low amount of root surface calculus in the experimental sample. In addition, choice of probing depth landmark had a notable effect on the outcomes for instrument efficiency and modified instrument efficiency. Ninety-five percent limits of agreement of interexaminer reproducibility were found to be much higher than intra-examiner measurement for all four methods of assessment.

CONCLUSIONS

Percentage apical plaque border appeared to be potentially more useful than other methods for assessing the efficacy of debridement of periodontally involved root surfaces, particularly for measuring instrument penetrability.

A comparison of the induction and emergence characteristics of sevoflurane and halothane in children

This open labelled, randomised, controlled study was designed to compare the induction and recovery characteristics of sevoflurane and halothane anaesthesia in children. Forty American Society of Anaesthesiologist (ASA) physical status class 1 or 2 children (aged 1-10 year, weighed less than 25 kg) scheduled for elective urological procedure lasting less than one hour were allocated randomly to receive either sevoflurane (group S, n = 20) or halothane (group H, n = 20). The induction time in children receiving sevoflurane was significantly shorter than in those receiving halothane (mean (SD) 46 (13.6) second vs 69 (19.4) seconds, p < 0.005). The emergence from anaesthesia was also faster in children receiving sevoflurane than in those receiving halothane (mean (SD) 9 min (4.3 min) vs 21 min (8.9 min), p < 0.001). No major adverse effects were encountered in each group. We concluded that sevoflurane is comparable to halothane in Malaysian children.

Acute bereavement care in the emergency department: does the professional-supported volunteers model work?

The aims of our study were to study the early impact of bereavement and to evaluate the effectiveness of the bereavement care given by our multidisciplinary team to close relatives of a sudden death, measured by the intensity of grief reaction (Texas Revised Inventory of Grief). The study sample consisted of close relatives of patients certified dead at the accident and emergency department (AED) between March 1996 and February 1997. The relatives received immediate care at the AED and were supported continually by the members of the bereavement care team. The control sample (without acute bereavement care) consisted of close relatives contacted by the liaison nursing officer in the previous year. The intensity of grief reactions were assessed by the volunteer grief counsellors at 6 months. The mean score of the intensity of grief reactions were 41.8 and 34.6 in the control (n = 11) and study (n = 18) groups respectively among high risk sample (p = 0.04). However, in the low risk sample, the mean scores were 35.3 and 30.2 in the control (n = 18) and study (n = 25) groups respectively (p = 0.11). Our study suggests that the bereavement care was especially effective in reducing the intensity of the grief at 6 months in the high risk group.

Pain during elective caesarean section under epidural anaesthesia: the effect of a 10° head-up tilt position

One hundred patients scheduled for elective caesarean section under epidural anaesthesia were randomized to have epidural loading doses in either the horizontal or a 10 degrees head-up position. They were assigned to their position only after an initial dose of 4 ml of 0.5% bupivacaine had been given. Ten minutes after this dose they were given 10 ml of 0.5% bupivacaine and 50 microg of fentanyl in their allocated position. Pain during surgery was assessed by the patients using a visual analogue scale and by a blinded anaesthetist. Giving the main dose in the head-up tilt position reduced the incidence of intea-operative pain significantly. The median pain score for the head-up position was zero while the score was two for the horizontal position. The inter-quartile range was 0 to 2 for the head-up tilt position and 0 to 4 for the horizontal position (P<0.05). Position had no significant effect on the blood pressure or Bromage score. A 10 degrees head-up tilt position is useful during the establishment of epidural anaesthesia to reduce the pain experienced by the patient during caesarean section.

Comparison of periodontal pocket penetration by conventional and microultrasonic inserts

Recently, 'microultrasonic' instruments have been developed with the aim of improving root-surface debridement. Whilst their reduced tip diameter and modified shape suggests that they may penetrate the periodontal pocket more easily than conventional inserts, there have been few studies investigating their efficacy. The aim of this investigation was therefore to compare the periodontal pocket penetration of a conventional ultrasonic insert (P10 insert--Dentsply) with microultrasonic inserts (Slimline FSI left and right--Dentsply). Efficacy of penetration was assessed by a modification of instrument limit. This modification permitted measurement of the linear % removal of the apical plaque border by image analysis. Debridement was carried out on randomly allocated surfaces of 30 teeth which had been treatment planned for extraction due to periodontitis. One surface on each tooth acted as an untreated control. The results of this study showed that both types of insert were able to reach and debride the apical plaque border, and at all pocket depths assessed. However no significant differences were found between the Slimline insert and the P10 tip. Trends between instruments were observed which suggest that the Slimline insert might more easily penetrate to and debride the apical plaque border in deep pockets, whereas the P10 insert might be more effective in disrupting the apical plaque border in shallow pockets. Future investigations using a larger sample size will be needed to confirm these observations.

Use of capnography delaying the diagnosis of tracheal intubation

There was a delay in making the correct diagnosis of tracheal intubation in a parturient who developed severe bronchospasm after intubation because we relied on the capnogram.

The nos (nitrous oxide reductase) gene cluster from the soil bacterium Achromobacter cycloclastes: cloning, sequence analysis, and expression

The nitrous oxide (N2O) reductase (nos) gene cluster from Achromobacter cycloclastes has been cloned and sequenced. Seven protein coding regions corresponding to nosR, nosZ (structural N2O reductase gene), nosD, nosF, nosY, nosL, and nosX are detected, indicating a genetic organization similar to that of Rhizobium meliloti. To aid homology studies, nosR from R. meliloti has also been sequenced. Comparison of the deduced amino acid sequences with corresponding sequences from other organisms has also allowed structural and functional inferences to be made. The heterologous expression of NosD, NosZ (N2O reductase), and NosL is also reported. A model of the CuA site in N2O reductase, based on the crystal structure of this site in bovine heart cytochrome c oxidase, is presented. The model suggests that a His residue of the CuA domain may be a ligand to the catalytic CuZ site. In addition, the origin of the spectroscopically-observed Cys coordination to CuZ is discussed in terms of the sequence alignment of seven N2O reductases.

The combination of omeprazole, amoxycillin, and clarithromycin eradicates Helicobacter pylori in 95% of patients---7 days of therapy is as good as 10 days

More than half of the known Helicobacter pylori strains are resistant to metronidazole, according to previous Hong Kong studies. The response rates to treatment regimens that comprise metronidazole as one of the antimicrobial agents have usually been disappointing in cases involving metronidazole-resistant strains. The objective of this open cohort evaluation was to assess the efficacy of an alternative regimen that combines omeprazole with amoxycillin and clarithromycin in Helicobacter pylor-positive ulcer and non-ulcer patients in Hong Kong. Furthermore, we aimed to investigate if 7 days were as good as 10 days of therapy. We studied 186 Helicobacter pylor-positive subjects; 149 subjects received 7 days of combination therapy and 37 subjects received 10 days. Our results showed that the overall Helicobacter pylori eradication efficiency was identical (94.6%) for both treatments. The incidences of adverse effects were also very similar (16.8% versus 16.2%) and both treatments were well tolerated. Thus, we propose that omeprazole in combination with amoxycillin and clarithromycin should be considered as one of the first-line therapies for patients with Helicobacter pylor infection in Hong Kong.

Discordance of pressure recordings from biliary and pancreatic duct segments in patients with suspected sphincter of Oddi dysfunction

It remains controversial whether manometric parameters recorded from the pancreatic and biliary segment of the sphincter of Oddi (SO) differ. We therefore studied 48 consecutive patients (40 women, 43 +/- 11 years) with suspected SO dysfunction, in 33 of whom successful dual-duct SO manometry was obtained. Measures of concordance between the two duct segments were moderate for basal sphincter pressure (K = 0.31) and for contractile frequency (0.35), and were low for peak pressure (0.15) and for proportion of retrograde propagation (-0.19). There was also low concordance (-0.13) for the overall manometric diagnosis, and in 48% (CI 31-66%) of patients a conflicting diagnosis (normal/abnormal) was obtained from the two ducts. There was no evidence of a differential motor effect of CCK on either duct, nor were there significant differences in the rate of manometric abnormality according to the order of initial duct cannulation. These results indicate that, if technically feasible, dual-duct manometry of the sphincter of Oddi is required for diagnostic precision.

Minimum prostate-specific antigen (PSA) level diagnostic of prostate cancer

The PSA levels in benign prostatic hyperplasia (BPH) and prostate adenocarcinoma (PA) overlap, both below and above 4 to 10 ng/mL. There is no known PSA level diagnostic of PA. In this study, data were obtained in 160 consecutive men aged 58 to 87. Prebiopsy PSA levels (PSA-1) were obtained prior to "sextant" gun biopsies in 97 cases diagnosed as noncarcinoma, and in 56 cases diagnosed as PA. Multiple hematoxylin and eosin sections were made of each biopsy, and Gleason scores given the PAs. Cases were followed up to 30 months with repeated PSA levels and additional biopsies. The highest PSA level in NPA in this series was 54.6 ng/mL.

Identification and analysis of the dissimilatory nitrous oxide reduction genes, nosRZDFY, of Rhizobium meliloti

The complete nos region essential for dissimilatory nitrous oxide reduction by the endosymbiotic diazotroph Rhizobium meliloti was identified in a cosmid (pYC7) carrying a 10.1-kb EcoRI fragment of the nod megaplasmid. This gene region was localized by Southern hybridization and Tn5 mutagenesis to within 8 kb downstream from the fixGHIS cluster. Nucleotide sequence determination of a 4.6-kb DNA segment including the structural gene nosZ and its flanking regions showed sequence homology and similarity in genetic organization with the nosRZDFY genes of Pseudomonas stutzeri Zobell. The genes were arranged in three complementation groups, comprising the nosZ structural gene, the nosR regulatory gene, and the nosDFY copper-processing genes. The derived amino acid sequence of the R. meliloti nosZ product (a multi-copper nitrous oxide reductase) was more similar to those of the analogous gene products of Paracoccus and Pseudomonas species than to that of Alcaligenes eutrophus. The nosZ gene was preceded by nosR, which encodes a regulatory protein containing C-terminal cysteine clusters similar to those present in the 4Fe-4S binding region of bacterial ferredoxins, The nosDFY genes, located downstream from nosZ, were identified as copper-processing genes encoding a periplasmic protein, an ATP/GTP-binding protein, and a membrane protein presumably forming a copper-processing system. A consensus sequence for an Anr- or Fnr-binding site similar to that in the upstream sequence of nosZ in Paracoccus denitrificans or P. stutzeri was absent in R. meliloti. No rpoN-binding site preceding the nos genes was detected, and none of the Tn5 insertions in the nos gene region affected symbiotic N2-fixing ability.

Extraperitoneal laparoscopy: anatomical dissections with experimental balloon dilators

OBJECTIVES

To develop balloon dilators in vitro and in cadavers and to evaluate the anatomy of the extraperitoneal spaces and their surroundings created by such balloons.

MATERIALS AND METHODS

Balloons of three different materials (condoms, fingers of surgical gloves, whole surgical gloves and 'party' balloons) were tested in an in vitro study and compared with a prototype balloon dilator used in cadavers. The balloon dilators were used to create extraperitoneal spaces in the pelvic, the loin and the iliac regions through stab incisions. The incisions were extended after dilatation to examine the spaces created and the consequent anatomical changes.

RESULTS

In vitro, all balloons were found to have capacities of more than 10 L, except that made from the finger of a surgical glove. Early rupture after insertion and during dilatation was a problem in condom and party balloons. In cadavers, there was good exposure of anatomical structures within the extraperitoneal spaces created. Reflections of peritoneum in the loin and the iliac regions were unmoved by balloon dilatation.

CONCLUSIONS

The prototype balloon dilator possessed all the characteristics desired of an ideal instrument for creating extraperitoneal spaces. Good exposure of anatomical structures by the balloon dilators allows a minimal dissection in extraperitoneal laparoscopic procedures in the aforementioned regions. That the peritoneal reflection was unmoved despite adequate expansion of the balloons also means that the exact placement of secondary laparoscopic ports is crucial in preventing peritoneal and colonic trauma.

Abnormal sphincter of Oddi response to cholecystokinin in postcholecystectomy syndrome patients with irritable bowel syndrome. The irritable sphincter

Standard biliary manometry, including cholecystokinin (CCK) provocation, was performed on 42 consecutive patients (36 F, 6 M, median age 45 years) with postcholecystectomy syndrome (PCS) who had no evidence of organic disease but who had objective clinical features suggesting sphincter of Oddi dysfunction (SOD) (classes I and II). Patients were subdivided into those with (N = 14) and without (N = 28) irritable bowel syndrome (IBS) using a validated symptom questionnaire based on the modified Rome criteria. Resting sphincter of Oddi (SO) motor parameters (basal pressure, contractile amplitude and frequency, and proportion of retrograde contractions), the presence of abnormal manometry, and the presence of an abnormal response to CCK were compared in the two groups. No significant differences in resting parameters of SO motor activity between patients with and without IBS were observed, and abnormal biliary manometry as a whole was not more prevalent in either group (8/13 and 18/27, respectively). An abnormal response to CCK (failure of complete inhibition of phasic contractions), however, was demonstrated in five of 12 patients with IBS compared with only one of 23 patients without IBS (P = 0.01). In patients with postcholecystectomy SOD, an abnormal response of the SO to CCK thus appears to be an important feature of the subset of patients with concomitant IBS.

Life satisfaction and associated factors in older Hong Kong Chinese

OBJECTIVE

To determine life satisfaction and its association with physical, functional, socioeconomic, psychological, and social support characteristics in Hong Kong Chinese aged 70 years and older.

DESIGN

Cross-sectional study.

SETTING

Territory-wide random sample of persons aged 70 years and older.

SUBJECTS

A total of 843 men and 714 women were selected by random sampling, stratified by age and sex, from the Old age and Disability Allowance Register, after exclusion of subjects with cognitive impairment.

MEASUREMENTS

Life satisfaction was assessed by the subjects' response to the question "Are you satisfied with life", using a 0 to 10-point linear scale. They were also asked to name the most important factor contributing to life satisfaction. Information was also obtained regarding physical health, functional ability, depressive symptoms, and socioeconomic factors.

RESULTS

There was a weak association between score and age. Health, adequate income to meet living expenses, and caring relatives were rated the most important factors (> 65%). Some of these factors were also those associated with a high life satisfaction score. Factors associated with a life satisfaction score greater than 6 points were higher social class and educational attainment, adequate income to meet living expenses, satisfactory living arrangement, Christianity, good social support, participation in social activities, functional independence, good self-perceived health, good hearing and vision, daily exercise, absence of recurrent falls, and low depressive symptom score. Multiple logistic regression identified having two or more relatives and tertiary education as positive associated factors, whereas inadequate income to meet expenses, dissatisfaction with living arrangement, nonparticipation in religious group activities, and a high depressive symptom score were negative associated factors.

CONCLUSION

In older Chinese, social factors such as the support provided by family members, as well as adequate income to meet living expenses, play a role equal to that of physical factors in contributing to life satisfaction.

Radiological diagnosis of accidental oesophageal intubation

Oesophageal intubation is rapidly fatal if not recognised. We report a patient who not only survived an oesophageal intubation but who had chest X-rays taken which showed an oesophageal intubation which was initially recognised by the attending physician.

Detection of a nitrous oxide reductase structural gene in Rhizobium meliloti strains and its location on the nod megaplasmid of JJ1c10 and SU47

The gene encoding a denitrification enzyme, nitrous oxide reductase (EC 1.7.99.6), in Rhizobium meliloti and other gram-negative bacteria was detected by hybridization to an internal 1.2-kb PstI fragment of the structural gene (nosZ) cloned from Pseudomonas stutzeri Zobell (W.G. Zumft, A. Viebrock-Sambale, and C. Braun, Eur. J. Biochem. 192:591-599, 1990). Homology to the probe was detected in the DNAs of two N2-fixing strains of P. stutzeri, two denitrifying Pseudomonas species, one Alcaligenes eutrophus strain, and 36 of 56 R. meliloti isolates tested. Except for two isolates of R. meliloti, all showed nitrous oxide reduction activity (Nos+). Therefore, at least part of the nosZ sequence appears to be conserved and widely distributed among denitrifiers, which include free-living and symbiotic diazotrophs. By using Agrobacterium tumefaciens transconjugants harboring different megaplasmids of R. meliloti JJ1c10 and SU47, sequence homology with the nosZ probe was unequivocally located on the nod megaplasmid. A cosmid clone of JJ1c10 in which nosZ homology was mapped on a 4.2-kb BamHI fragment was selected. This cosmid, which conferred Nos+ activity to the R. meliloti wild-type strains ATCC 9930 and Balsac (Nos- and nondenitrifying, respectively) also restored Nos+ activity in the mutants of JJ1c10 and SU47 in which the 4.2-kb BamHI segment was deleted. Therefore, this segment contains sequences essential for nos gene expression in JJ1c10 and SU47 and thus confirms that the nod megaplasmid in JJ1c10 and SU47 which carries genes essential for symbiotic dinitrogen fixation also carries genes involved in the antagonistic process of denitrification.

Efficient culture of Chlamydia pneumoniae with cell lines derived from the human respiratory tract

Two established cell lines, H 292 and HEp-2, originating from the human respiratory tract, were found to be significantly more efficient and practical than the currently used HeLa 229 cells for growth of Chlamydia pneumoniae. Six strains of C. pneumoniae recently isolated from patients with respiratory ailments were used as test cultures. The H 292 and HEp-2 cells yielded much higher inclusion counts for all the test strains than did HeLa 229 cells. When they were compared with each other, H 292 cells yielded more inclusions than did HEp-2 cells, and the differences were statistically significant in 10 of 18 test sets. A simple system with these two cell lines appeared to be very efficient for culturing C. pneumoniae. It does not require treatment of tissue cells with DEAE-dextran before infection, and it may eliminate the need for serial subpassages of specimens to increase culture sensitivity. Monolayers of these cells remained intact and viable in the Chlamydia growth medium so that reinfection could take place, resulting in greatly increased inclusion counts for specimens containing few infectious units. This system may make it more practical for laboratories to culture for C. pneumoniae for treatment of infections and outbreak intervention and will facilitate studies on this recently recognized pathogen.

Xq28: epidemiology and sex-linkage between red-green colour blindness and G6PD deficiency

Xq28 is the genetic locus of two closely associated conditions of red-green colour blindness and G6PD deficiency. Epidemiologically, both rank among the more frequent sex-linked clinical problems that affect military servicemen in Singapore. This retrospective study is based on the findings of 35714 subjects screened at the Medical Classification Centre--Central Manpower Base (MCC--CMPB) over an eighteen-month period using pseudoisochromatic and fluorescent techniques as well as anomaloscopic and spectrometric methods. The overall prevalence rates of red-green colour blindness, G6PD deficiency and association were determined to be 4.8%, 2.2% and 0.1% respectively. Malays showed the highest prevalence rates among the major races. Statistically significant difference was found with regards to the prevalence rates of G6PD deficiency and its association with red-green colour blindness. Review of literature yielded comparable results with a few local studies of good sample size done over the past twenty years. Sex-linkage analysis was hindered by the lack of pedigree studies.

A comparison of sodium citrate and sodium citrate/ranitidine combination for acid aspiration prophylaxis

The effectiveness of sodium citrate and sodium citrate/ranitidine were compared in two randomised groups of elective caesarean patients during the various phases of anaesthesia. The mean pH values (3.5, 3.3, 3.6) were lower in the citrate group compared to the citrate/ranitidine group (6.1, 6.3, 5.9). The percentage of patients with pH values less than 2.5 was 40% in the citrate group compared to 7% in the citrate/ranitidine group. Sodium citrate alone is less effective than sodium citrate/ranitidine for acid aspiration prophylaxis.

Cardiac effects of prazosin in chronic aortic insufficiency

Eight patients with chronic moderate to severe aortic insufficiency were assessed by radionuclide angiography at rest and during maximal bicycle exercise after six weeks of placebo, six weeks of prazosin titration up to 10 mg bid and 12 weeks of prazosin maintenance therapy. Prazosin was well tolerated and the final dose amounted to 18.6 +/- 0.7 mg/day. Exercise performance tended to increase (from 8.9 +/- 1.1 to 9.6 +/- 0.8 mins). Resting and exercise blood pressure and heart rate were not affected by prazosin. Left ventricular volumes were decreased and exercise ejection fraction increased by prazosin. Total left ventricular output decreased, whereas regurgitant index improved. The authors conclude that in patients with chronic moderate to severe aortic insufficiency, chronic prazosin therapy causes persistent improvements in left ventricular anatomy and function both at rest and during exercise.

Persistent liver dysfunction among workers at a vinyl chloride monomer polymerization plant

Thirteen workers with persistent abnormalities in one or more liver function tests (LFT) at a vinyl chloride monomer (VCM) polymerization plant were investigated. Twelve workers were found to have VCM-induced liver dysfunction based on circumstantial evidence. They were employed between 1971 and 1982 when the VCM levels ranged from 1 to 21 p.p.m. After 1982 when the environmental VCM levels were controlled to below 1 p.p.m., no cases of VCM-induced liver dysfunction were detected. In most cases, glutamic pyruvic transaminase was the earliest parameter to be raised. The second most common parameter is serum gamma glutamyl transpeptidase. The latent period ranged from 1 to 13 years. An improvement in their LFT results was shown by 83.3 per cent of workers within 6 months to 2 years after removal from further VCM exposure. For workers who returned to VCM work, their LFT became abnormal again. Liver scans showed hepato and/or splenomegaly in most cases. Liver biopsies on 9 workers were reported as 'non-specific fatty changes' of varying degrees. These observations highlight the need for continual vigilance with environmental monitoring and medical surveillance of VCM-exposed workers.

Epinephrine and left ventricular function in humans: effects of beta-1 vs nonselective beta-blockade

Changes in cardiac performance in response to epinephrine administered by graded infusion were assessed by M-mode echocardiography in normotensive healthy subjects after pretreatment with placebo, the beta 1-selective blocker atenolol, or the nonselective beta-blocker propranolol. Epinephrine alone increased heart rate and left ventricular end diastolic dimension and decreased left ventricular end systolic dimension. Left ventricular performance as assessed by fractional shortening and systolic blood pressure/end-systolic volume (P/V) ratio was also increased. Atenolol pretreatment did not significantly affect the increase in heart rate by epinephrine. However, atenolol did prevent the effects of epinephrine on left ventricular dimensions and left ventricular performance at the lower infusion rates and significantly blunted these effects at the highest infusion rate. After propranolol, epinephrine significantly decreased left ventricular end diastolic dimension despite decreasing heart rate and left ventricular emptying (associated with a high afterload). P/V ratio remained unchanged. These results indicate that beta 2-receptors may play a major role in the increase in heart rate caused by epinephrine. In contrast, epinephrine's positive inotropic effect appears to be mediated primarily via beta 1-receptors and, at higher concentrations, possibly also through beta 2-receptors. The pattern of changes in left ventricular end diastolic dimension suggests that epinephrine increases venous return via both beta 1- and beta 2-receptor stimulation and that alpha-receptor stimulation (epinephrine after propranolol) may actually decrease venous return.