The effect of an absorbable collagen membrane on the subgingival microflora

The purpose of this study was to determine the effect of use of an absorbable collagen membrane in guided tissue regeneration (GTR) therapy upon the subgingival microflora. The study group consisted of 12 systemically healthy patients with bilateral mandibular furcation defects with attachment loss > or = 6 mm; one site was randomly assigned for GTR treatment while the contralateral site received surgical flap debridement only. Subgingival plaque samples were collected by paper point on the day of surgery and at 2, 4 and 6 months post-surgery. Three sites were sampled in each patient: a collagen membrane site, a control surgical site, and an unoperated control site. Plaque samples were transported in a non-phosphated buffer solution and examined by phase-contrast microscopy. Cocci, rods, spirochetes, fusiforms, curved rods, and total bacteria were recorded per 10 high-power fields. Following statistical analysis utilizing the Bonferroni (Dunn) t test, no differences in total bacterial counts were found among the sites at any of the time intervals examined. Total bacterial counts were found lower at both the collagen membrane and control surgical sites post-surgery as compared to unoperated control sites, but these differences were not statistically significant (P > .05). In addition, no significant differences were detected in bacterial profiles between sites or individual time points. Results from this 6-month limited clinical trial suggest that the placement of an absorbable collagen membrane as part of a standard surgical regimen for GTR therapy does not alter the local microflora.

Predictive value of MCV/RBC count ratio to discriminate between iron deficiency anaemia and beta thalassaemia trait

AIM AND BACKGROUND

Two forms of hypochromic microcytic anaemia i.e. iron deficiency and beta-thalassaemia trait are common in our society. This study reports the prevalence of iron deficiency anaemia and beta-thalassaemia trait and predictive value of MCV/RBC count ratio to discriminate between two.

METHODS

Venous blood was taken from 299 students of Karachi Medical & Dental College and Ziauddin Medical University in Na2 EDTA and analyzed by semi-automated Sysmex K-1000 haematology analyzer. MCV/RBC count ratio was used to discriminate between iron deficiency and beta-thalassaemia trait and > 14% was marked as iron deficiency. Hb electrophoresis was used as gold standard test for confirmation. Serum iron and TIBC was performed to confirm iron deficiency anaemia.

RESULTS

Iron deficiency was found in 9% while beta-thalassaemia was seen in 3% students. MCV/RBC count ratio showed a positive predictive value of 91%.

CONCLUSIONS

In areas where iron deficiency anaemia and beta-thalassaemia trait are common, MCV/RBC count ratio can be used to screen out beta-thalassaemia trait.

Isolation and identification of Aeromonas species from human stools

One thousand and three diarrhoeal stool samples were processed in our laboratory during the period 1996/1997 for the presence of enteric pathogens especially Aeromonas spp., which has emerged as a new agent causing diarrhoea. Ampicillin sheep blood agar was found to be the best medium for the isolation of Aeromonas spp. from stool specimens. Enteric pathogens were found in 200 (20%) stools, of which Aeromonas spp. was the second commonest pathogen isolated amounting to 21% of isolates. This study clearly indicates that Aeromonas spp. must be looked for in every diarrhoeal stool samples, specially in children below 10 years of age. Isolation and identification is cost effective and easy, if the given protocol is observed.

Potent antithrombin activity and delayed clearance from the circulation characterize recombinant hirudin genetically fused to albumin

In this study we sought to extend the plasma half-life while maintaining the potent antithrombin activity of hirudin. We hypothesized that gene fusion of hirudin to albumin would result in the expression of a slowly cleared hirudin molecule. A hirudin variant 3 (HV3) cDNA was obtained by gene synthesis, while a 1,996-bp full-length rabbit serum albumin (RSA) cDNA was selected from a rabbit liver cDNA library. Expression of the former in COS-1 cells conferred antithrombin activity on media conditioned by the cells, while expression of the latter resulted in the secretion of a 67-kD protein that reacted with mono-specific anti-RSA antibodies. Having shown independent expression of the two proteins, we next expressed two fusion proteins: HV3 linked via its C-terminus to albumin (HLA), and HV3 linked via its N-terminus to albumin (ALH). The former, but not the latter, inhibited both the amidolytic and fibrinogenolytic activities of thrombin. HLA also retained the dye-binding characteristics of RSA, as judged by Affi-Gel Blue chromatography. Highly similar concentrations of either commercial HV1 (40 nmol/L) or HLA (30 nmol/L) were required to halve the initial rate of thrombin reaction with chromogenic substrate S2238, suggesting the retention of high-affinity inhibition of thrombin by the fusion protein. An His-tagged form of HLA was purified by Ni2+-chelate affinity and heparin-Sepharose chromatography. The purified, radioiodinated protein was injected into rabbits, and demonstrated a catabolic half-life of 4.60 +/- 0.16 days. This represents an extension of hirudin half-life in vivo of greater than two orders of magnitude; gel analysis of HLA(H)6 recovered from rabbits showed that it circulated in intact form. Our results provide a rationale for future testing of the biological effects of HLA, and support our initial hypothesis.

Inhibition of thrombin by hirudin genetically fused to wild-type or mutant antithrombin

Recombinant fusion proteins consisting of hirudin variant 3 (HV3) fused at its C-terminus to either of two forms of mature rabbit antithrombin (AT) were generated in COS-I cells. HV3 fused to wild-type AT was designated HAT, while a similar chimeric protein in which the P12 residue of AT was mutated from Ala to Thr, was designated HAT(H) for the Hamilton (A382T) mutation. Addition of the HV3 domain resulted in a decreased mobility of both HAT and HAT(H) relative to COS-derived AT (68 kDa versus 60 kDa). Both proteins had a greatly increased ability to inhibit thrombin in amidolytic activity assays, relative to recombinant AT. Addition of heparin to these reactions was without effect. Incubation of conditioned media containing recombinant AT with 125I-labelled thrombin resulted in the formation of SDS-stable AT-IIa complexes; no such complexes were detected in identical reactions containing either HV3-AT fusion protein. The two proteins did not differ significantly in their ability to compete for the binding of 125I-labelled thrombin to immobilized HV1 (CGP 39393). Both proteins were found to bind to heparin-Sepharose, but less tightly than unfused AT. This property was demonstrated by the peak elution of the fusion proteins at 0.65 M NaCl, as compared to that of COS-derived AT at 1.05 M NaCl. We conclude that the fusion proteins inhibit thrombin with similar affinity to unfused hirudin via their hirudin and not their antithrombin domains. The heparin-binding capability of these proteins may indicate the acquisition of vessel wall binding capacity by these novel forms of recombinant hirudin.

Role of the pulsed dye laser in the management of ulcerated capillary haemangiomas

A complication of capillary haemangiomas is ulceration, which may arise after trauma and/or infection. Until recently, conservative management was the rule. However, the recent advent of the pulsed dye laser has revolutionised the treatment of vascular birthmarks and provided a new tool for the management of capillary haemangiomas. Thirteen cases of ulcerated capillary haemangiomas referred to our department were reviewed; five were treated conservatively and eight were treated with the laser. Those treated with the laser had all failed conservative management and healed completely within one to four weeks. Remarkably rapid alleviation of pain was achieved. For those haemangiomas around the mouth and perineum, laser treatment enabled early restoration of normal feeding, micturition, and defaecation. It is therefore recommended that if ulcerated capillary haemangiomas do not improve after a short period of optimal conservative treatment, laser treatment should be considered.

A new audiovisual technique for recording blood pressure in research: the Sphygmocorder

OBJECTIVE

To devise a method of blood pressure measurement capable of being substituted for the fallible human observer in validation of blood pressure measuring devices.

DESIGN

A number of components used to measure blood pressure have been combined innovatively with audiovisual recording technology to produce a system, named the Sphygmocorder, which consists of a mercury sphygmomanometer, an occluding cuff, an inflation source, a stethoscope, a microphone capable of detecting Korotkoff sounds, a camcorder and a display screen.

METHODS

To determine the accuracy of the Sphygmocorder against the trained human observer, the Sphygmocorder has been validated in three separate studies in which three devices for self-measurement of blood pressure, the Omron HEM-705CP, the Phillips HP5332 and the Nissei DS-175, were being validated against two trained observers in 85 subjects with a wide range of blood pressure according to the protocol of the British Hypertension Society.

RESULTS

The Sphygmocorder was as accurate as at least one of the observers in each of the validation studies and therefore allows replacement of trained observers by the new device.

CONCLUSION

The Sphygmocorder, which retains the time-honoured technique of blood pressure measurement with a mercury sphygmomanometer and an auscultating observer, and provides, in addition, objective evidence of the measurement recorded, which can be stored and re-examined, can be used as a substitute for human observers in validation studies of blood pressure-measuring devices.

Marginal discrepancy of all-ceramic crowns cemented on implant abutments

PURPOSE

The purpose of this investigation was to determine the mean marginal discrepancy of all-ceramic crowns cemented on implant abutments.

MATERIALS AND METHODS

Five Brånemark CeraOne abutments were connected to implant fixtures embedded in acrylic resin blocks. The marginal discrepancy was measured using a video camera connected to a digitizing board at four locations on each abutment for five samples in each of the following groups: all-ceramic caps (caps), all-ceramic crowns (crowns), and all-ceramic crowns cemented with zinc phosphate cement (cemented crowns).

RESULTS

The mean marginal discrepancies were as follows: caps, 99.0 micrometers (SD, 16); crowns, 117.8 micrometers (SD, 20); and cemented crowns, 168.8 micrometers (SD, 23). Statistically significant differences were found between all three groups at the 99% level of confidence. In addition there were two significant differences between abutments.

CONCLUSIONS

Subgingival marginal discrepancies of the magnitude measured in this study have been shown to cause periodontal problems. It is probable that the marginal discrepancy of CeraOne restorations, as tested, can be improved. Efforts should be made to enhance the marginal accuracy of these restorations.

Helicobacter pylori clearance and eradication with triple therapy in duodenal ulcer patients

Triple therapy was given to 49 chronic helicobacter pylori positive chronic duodenal ulcer cases to see its efficacy in H. pylori clearance, eradication and ulcer healing. H. pylori clearance and eradication rates at week 5 and 8 were 87.8% and 81.5% while ulcer healing rates 68.2% and 81.5% respectively. Seven (18%) cases failed to clear H. pylori and were classified as non-responders. Histologically 60% showed post-treatment regression of gastritis. Tolerance to drugs was excellent with a good compliance rate.

Adherence of oral microorganisms to guided tissue membranes: an in vitro study

Microorganisms can adhere and colonize on an exposed guided tissue regeneration (GTR) membrane thus developing a nidus of infection. The purpose of this study was to compare early bacterial adhesion to three different GTR membranes. Expanded polytetrafluoroethylene, polyglactin 910, and collagen were used as the test membranes. In part I of this study 15 different oral microbes were used to compare their relative ability to adhere to the membranes. Six of the most strongly adherent bacteria (Actinomyces viscosus, Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Streptococcus mutans, Fusobacterium nucleatum, and Selenomonas sputigena) were selected for part II of this study. The membranes were placed in tubes containing broth cultures containing identical concentrations (1 x 10(8) cells/ml) of these bacteria at 37 degrees C. Membranes were placed in tubes of media without bacteria as controls. At 4, 6, 12, and 24 hours, the bacterial cultures were decanted and the membranes in the tubes were agitated gently in reduced transfer fluid (RTF) 4 times to remove non-adherent bacteria. Each tube was then sonicated for 30 seconds in 10 ml RTF to detach adherent bacteria. The detached adherent bacteria were counted using a Petroff-Hausser chamber. Data were analyzed by using the SAS program. Analysis of variance was used to test for differences between multiple means. Results showed S. mutans had the strongest attachment to the collagen membrane at 4 and 6 hours. Selenomonas sputigena had the lowest adherence capability to all test membranes. Polyglactin 910 had significantly (P < 0.05) lower S. mutants adherence than either the ePTFE or the collagen membrane at 4 and 6 hours.(ABSTRACT TRUNCATED AT 250 WORDS)

Microbial colonization of dental implants in partially edentulous subjects

This study assessed the colonization of Brånemark dental implants by periodontopathic bacteria in four partially edentulous patients with a total of 10 implants. Marginal and subgingival plaque on the implants was sampled 14 days and 28 days after second-stage surgery and compared with plaque from three teeth closest to the implant sites sampled before second-stage surgery (baseline) and at 14 and 28 days. Slot immunoblot assay was used to determine the presence or absence of bacterial antigen to six different periodontopathic microorganisms. In general, colonization of marginal implant plaque occurred within 14 days, whereas subgingival colonization took longer and occurred within 28 days. It appears that Brånemark dental implants placed in partially edentulous patients may be colonized by disease-associated bacteria within 14 days of second-stage surgery.

In vivo and in vitro methylation of lysine residues of Euglena gracilis histone H1

We have earlier identified and purified two protein-lysine N-methyltransferases (Protein methylase III) from Euglena gracilis [J. Biol. Chem., 260, 7114 (1985)]. The enzymes were highly specific toward histone H1 (lysine-rich), and the enzymatic products were identified as epsilon-N-mono-, di- and trimethyllysines. These earlier studies, however, were carried out with rat liver histone H1 as the in vitro substrate. Presently, histone H1 has been purified from Euglena gracilis through Bio-Rex 70 and Bio-Gel P-100 column chromatography. The Euglena histone H1 showed a single band on SDS-polyacrylamide gel electrophoresis and behaved like other histone H1 of higher animals, whereas it had a much higher Rf value than the other histones H1 in acid/urea gel electrophoresis. When the Euglena histone H1 was [methyl-3H]-labeled in vitro by a homologous enzyme (one of the two Euglena protein methylase III) and analyzed on two-dimensional gel electrophoresis, three distinctive subtypes of histone H1 were shown to be radiolabeled, whereas five subtypes of rat liver histone H1 were found to be labeled. Finally, by the combined use of a strong cation exchange and reversed-phase Resolve C18 columns on HPLC, we demonstrated that Euglena histone H1 contains approximately 9 mol% of epsilon-N-methyllysines (1.40, 1.66, and 5.62 mol% for epsilon-N-mono-, di- and trimethyllysines, respectively). This is the first demonstration of the natural occurrence of epsilon-N-methyllysines in histone H1.

H2 receptor antagonist or H. pylori eradication?

To assess the healing and relapse rate of duodenal ulcer (DU) treated with H2 receptor antagonists in helicobacter pylori (HP) positive vs negative cases, we analysed 95 cases of endoscopically proven duodenal ulcer. H. pylori colonization was found in 73 (77%) patients before treatment. No difference was observed in the pre-treatment characteristics between patients with HP positive and HP negative duodenal ulcers. Healing rates with H2 receptor antagonist at 8 weeks were 90% and 91% respectively (NS). No difference in HP colonization was found between patients with and without healed ulcerie, 77% and 78% respectively. Relapse rate within 1 year was 50% in patients with HP positive vs 73% with HP negative cases. We conclude that duodenal ulcer healing and relapse rate is related to acid inhibition rather than HP colonization.

Economy and quality assessment of home made clinical chemistry reagents

Most laboratories in Pakistan use expensive imported clinical chemistry reagent kits resulting in high cost/test to the patients. To reduce these costs, reagents were prepared from basic chemicals, substrates and enzymes imported from Sigma Chemical Company U.K. This reduced the cost/test by up to 500% in some reagents. The quality of these reagents was tested by Wellcome External, Q.C. Locally prepared reagents were comparable to or better than commercial reagents systems in terms of accuracy and precision. This paper describes the preparations according to I.F.C.C., costs and quality control of some of the reagents i.e., glucose, calcium, bilirubin, albumin, total protein, urea, ALT, AST and LDH and their comparisons with equivalent commercial kits.

Thyroid hormone levels in hepatitis B

Thyroid hormone levels were estimated in fifty patients with hepatitis B. In acute phase, T3 was raised in 10% and T4 in 60%. This rise was directly proportional to the transaminases levels. Twenty cases were also studied in the recovery phase where thyroid hormones returned to within normal limits. This rise of T3 and T4 in acute phase is attributed to increased thyroxin binding capacity due to release of thyroid binding globulin into circulation from necrosing hepatocytes.

Oesophageal changes in oral submucous fibrosis using fibreoptic endoscopy--a pilot study

Thirty patients with oral submucous fibrosis (OSMF) underwent fibreoptic upper G.I. endoscopy and oesophageal biopsy from 20 cms to see if any correlation is found between visual and histological changes in OSMF and oesophageal mucosa. On endoscopy, the colour of oesophageal mucosa was normal in 28 and whitish pale in 2 cases. On endoscopy mucosa felt stiff and fibrotic in 19, leathery in 4, firm/gritty in 2 and normal in 5 cases. The biopsies were difficult to take in most cases yielding small tissue samples on repeated attempts. On histology most of the samples consisted of only a few layers of hyperplastic epithelium with lamina propria and submucosa being absent in all samples. Good correlation was found between the grade of OSMF and oesophageal changes seen on endoscopy.

Biochemical comparison of proteolytic enzymes present in rough- and smooth-surfaced capnocytophagas isolated from the subgingival plaque of periodontitis patients

Four rough-surfaced (R) and three smooth-surfaced (S) clinical isolates of Capnocytophaga obtained from the subgingival plaque of periodontitis patients were studied for their peptidase and protease profiles. The results were compared with those obtained with C. gingivalis (which has a smooth morphology). All cell extracts obtained by ultrasonic treatment displayed high peptidase activity toward N-aminoacyl-2-naphthylamines, the best substrates being the arginyl, aspartyl, and leucyl derivatives. The R and S isolates did not differ in these enzyme activities. Also the protease profiles studies with 4-phenylazobenzyloxycarbonyl-L-prolyl-L-leucylglycyl-L-proly l-D-arginine (PZ-PLPGA) and casein were similar. All extracts also hydrolyzed furylacryloyl-L-leucylglycyl-L-prolyl-L-alanine (FALGPA), reconstituted type I [3H]-collagen, and gelatin. N alpha-Benzoyl-DL-rginyl-2-naphthylamine was hydrolyzed faster by the R than the S strains. Comparison between cell suspensions and cell extracts of C. gingivalis showed the suspensions to be enzymatically more active than the extracts. In general, peptidase substrates and PZ-PLGPA were hydrolyzed at a higher rate by suspensions than by extracts, while protease substrates (such as casein) were hydrolyzed faster by the extracts. Gelatin and FALGPA were hydrolyzed by cell extracts only. Fast protein liquid chromatography of peptidases on a gel column was found to be a suitable method to differentiate between R and S isolates in diagnostics, while the chromatographic profiles of proteases were not suitable for this purpose.

Controlled trial of the prolactin inhibitor bromocriptine (Parlodel) in the treatment of severe cyclical mastalgia

Fifty pre-menopausal women with severe and persistent cyclical mastalgia entered this randomised, double-blind, parallel group study comparing bromocriptine and placebo. Patients were treated for three months followed by a further three months on the same medication if treatment was satisfactory. Symptoms were assessed before treatment and after one, two and three months of treatment. For patients whose mastalgia was not controlled after three months, the treatment code was broken and either the dose of bromocriptine increased or the patient given active medication instead of placebo. Bromocriptine, compared with placebo, caused a significant (p less than 0.01) and sustained improvement in breast pain, tenderness and nodularity together with a reduction in serum prolactin levels (p less than 0.01). Adverse events were experienced by 9/23 (39 per cent) of patients taking bromocriptine and 2/22 (nine per cent) taking placebo. The majority of side effects reported were mild or moderate. This study shows that bromocriptine, at a dose of 5 mg/day for three months, effectively controls the symptoms of cyclical mastalgia with minimal side effects.

Relationship between oxygen tension and subgingival bacterial flora in untreated human periodontal pockets

The predominance of anaerobic bacteria in subgingival plaque samples suggests that the pocket environment is anaerobic. In the present investigation, a small oxygen tension (pO2) electrode was inserted into the base of the pocket and the pO2 was recorded. In addition, the plaque in these pockets was examined culturally and microscopically. The oxygen tension at the bottom of 36 pockets (5 to 10 mm in depth) ranged from 5 to 27 mmHg (1 mmHg congruent to 133.3 Pa) with a mean value of 13.3 mmHg. Moderate pockets (5 and 6 mm) exhibited a mean pO2 of 15.7 mmHg, which was significantly higher than the 12.0 mmHg found in the deeper pockets. The deep pockets had higher percentages of spirochetes and Bacteroides intermedius, whereas the moderate pockets had elevated proportions of Actinomyces naeslundii and Streptococcus mutans. The sites with oxygen tensions equal to or less than 15 mmHg had significantly higher percentages of spirochetes, whereas the microaerophilic Capnocytophaga species were found in pockets with a pO2 greater than 15 mmHg. The presence of bleeding in the pocket was associated with higher proportions of B. intermedius, Capnocytophaga sp., and A. naeslundii. These pO2 readings of periodontal pockets indicated that there is a spectrum of pO2 values which seem to define, in a general way, the microbiological composition of the pocket.

Cardiac tamponade caused by metastasising haemangioendothelial sarcoma of the liver

A case of primary haemangiosarcoma of the liver with secondary deposits in the pericardium is described. The patient presented most unusually with cardiac tamponade. There was no association with vinyl chloride, thorium dioxide, or arsenic.