Comparative study of the osteoblastic activity of two implant systems (Endopore versus Entegra) utilizing single photon emission computed tomography (SPECT): experimental study in pigs model

Implantology has been an important component of dental management for over forty years, and during that period, many configurations of implant materials and methods have been developed. As empirical and clinical research yield new implant materials, there has been need to test and compare these materials to provide the most cost-effective and efficient implants. Evaluation of efficiency of implants has relied heavily on histological and radiological methods, but these one-dimensional measurement methods fail to evaluate the osteoblastic activity and osseointegration properties of putative implants. In this report, we describe the use of a quantitative single photon emission computed tomography (SPECT) as a tool for comparing the osseointegrating capabilities of two types of implants.

Comparative study of osteoblastic activity of same implants (Endopore) in the immediate extraction site utilizing single photon emission computerized tomography: peri-implant autogeneous bone grafting with GTR versus no peri-implant bone grafting--experimental study in pig model

The study was designed to exploit the single photon emission computerized tomography (SPECT) to compare osteoblastic activity of two implant systems: an Endopore implant (Beaded implants) placed immediately into an extraction socket in conjunction with peri-implant autogenous grafting supplemented with a guided tissue regeneration (GTR) technique, and an Endopore implant placed immediately into the extraction socket without peri-implant grafting and GTR. Endopore implants of the same size (12 mm x 4.1 mm INT-Hex) were placed in fresh extraction sockets in the canine-tooth region of the pigs jaw. The implant on the right side had peri-implant bone grafting utilizing autogenous bone together with cytoplast resorbable GTR membrane, whilst the implant on the left side received no peri-implant bone grafting. Osteoblastic activity was evaluated 81 days (11 weeks and 4 days) post implantation using the SPECT imaging technique. The SPECT imaging revealed more osteoblastic activity on the side with peri-implant bone grafting as compared with the site without peri-implant bone grafting. The result suggests that peri-implant bone grafting with GTR around the immediate implant showed more osteoblastic activity and thus enhanced osseointegration when compared with the implant without bone grafting and GTR. Bone grafting and GTR should be encouraged as a standard procedure with dental implants.

Prevalence and antimicrobial susceptibility pattern of pathogens isolated from patients with juvenile periodontitis in Jamaica: a prospective multi-centre study of 15 cases over a 15-year period

Prevalence and antimicrobial susceptibility pattern of most frequent pathogens isolated from patients treated with juvenile periodontitis at three separate dental centres in Jamaica from 1989 to 2003 were studied. Swabs were taken from these patients periodontal pathologic pocket or root of most of their teeth with active disease processes. These swabs were processed at the microbiology department of the University Hospital of the West Indies Kingston, Jamaica and the Microbiology laboratory, School of Veterinary Medicine, Faculty of Medical Sciences, University of the West Indies, St. Augustine, Trinidad and Tobago. The identification of the micro-organisms from positive cultures and their antimicrobial susceptibility profile were performed using standard microbiological procedures and dick diffusion (Kirby-Bauer) methods. Over 80% of the patients were females. The most frequent micro-organisms isolated were Enterobacter (40.5%), followed by Klebsiella species (19%) and Acinetobacter species (10.8%). Actinobacillus actinomycetemcomitans, a widely known key pathogen in juvenile periodontal diseases was encountered only in 5.4% (2/37) of the cases in this study The most frequent organism isolated were still highly susceptibility to the commonly used and available antimicrobials such as amoxycillin/clavulanate, trimethoprim/sulphamethoxazole, chloramphenicol and aminoglycosides. The most frequent pathogens encountered in this study were totally different from what obtains in other places. There is the need to be aware of microbes in other countries during the microbiology investigations ofjuvenile periodontitis and that the antimicrobial chemotherapy should always be based on susceptibility test results. Surgical treatment for mechanical debridement of the site and bone grafting with guided tissue regeneration should be mandatory in conjunction with specific antimicrobial chemotherapy

Single photon emission computerized tomography in the evaluation of the osteoblastic activities of a new bone regeneration technique: analysis of 12 mandibular sites in six experimental pigs

OBJECTIVES

To utilize single photon emission computerized tomography performed in sequence to determine the osseo-integrating capabilities and osteoblastic activities of a new bone regeneration technique called the membrane--sandwich technique (Ogunsalu sandwich bone regenerating technique) and to compare the quality and quantity of bone formed by this bone regeneration unit to bone regeneration obtained by using the same particulate bone grafting material covered with interceed (another type of bio-resorbable membrane).

DESIGN AND METHOD

Single photon emission computerized tomography bone imaging was performed in sequence on the mandible of a total of 6 pigs on both the right and left side (total of 12 sites) at two and a half hours following the injection of technetium 99m methylene diphosphate. Imaging was performed using a Siemen Orbitar II gamma camera. The projection data was acquired in a 128 x 128 matrix over 180 arc and SPECT reconstruction was performed using a filtered back projector method with a Shepp-Logan Hanning filter and a cut-off frequency of 0.4. The surgical defect on one side of the jaw was treated with the sandwich unit with Bio-oss particulate bone within it, while the other side contained the same quantity of Bio-oss as in the left side but just covered with interceed membrane. The osteoblastic uptake on the side with the classical sandwich was compared to the side with the particulate bone covered with interceed membrane for dynamic physiological activities. The average activity for both sides was calculated and compared.

RESULT

For all the 12 sites, osteoblastic activities were recorded and indicated that vascularized bone was formed at all the experimental sites. Autogenous bone graft was confirmed to be superior to xenograft using this sandwich technique. Furthermore, the osteoblastic activities on the sandwich side were seen to be more when compared with the control side (Interceed side).

CONCLUSION

The Ogunsalu sandwich bone regeneration technique has been successfully evaluated with SPECT which shows osteoblastic activity with formation of vascularized bone which integrates with the surrounding bone.

Single photon emission computerized tomography and histological evaluation in the validation of a new technique for closure of oro-antral communication: an experimental study in pigs

Various bone regeneration techniques have evolved recently but controversies regarding vascularization and integration of such bone grafting techniques have led occasionally to animal experiment to validate such techniques. The objective of this study was to evaluate the evidence of vascularization and osseo-integration of a new bone regeneration technique utilized for the closure of oro-antral communication (OAC) by an experimental model in which Single Photon Emission computerized Tomography and histological studies were conducted in pigs. We conclude that the sandwich technique used for the closure of OAC results in a vascularized new bone formation which eventually osseo-integrate with the surrounding bone. Also, this experimental study confirmed that autogeneous bone graft was superior to xenografts when used within the sandwich unit.

Odontogenic Keratocyst in Jamaica: a review of five new cases and five instances of recurrence together with comparative analyses of four treatment modalities

AIM

Five new cases of odontogenic keratocyst (OKC) together with five instances of recurrence are reviewed with special emphasis on radiology and surgical management. A comparative analysis offour different treatment modalities used in the treatment of OKC in these patients (new and recurrent cases) is reported.

SUBJECTS AND METHODS

The case notes and radiographs ofpatients who had histological confirmation of OKC at both the Cornwall Regional Hospital and Kingston Public Hospital in Jamaica were reviewed for demographics, radiological presentation, treatment modalities and outcome of treatment. Cases of recurrence were separated from new cases. This study was conducted for the period 1980 to 2004.

RESULTS

Five new cases and five instances of recurrence were documented over the 25-year period The new cases of OKC keratocyst accounted for 1.71% of the total jaw bone tumours and 12% of OKC keratocysts over the first 16 years. The posterior mandible appears to be the most favoured site. Of significance, one case of nevoid basal cell carcinoma syndrome (NBCCS) and a case of ameloblastomatous transformation in the wall of an OKC keratocyst were recorded The age range of the new cases was 12 to 44 years.

CONCLUSION

The radiological finding from this review is similar to previous reports. However the authors record a unique and historic case of ameloblastomatous transformation of OKC. A case of OKC in NBCCS is also documented Of all four surgical treatment modalities compared, only cryosurgery was promising, so far with no recurrence after a follow-up period of six years.

A new radiological classification for ameloblastoma based on analysis of 19 cases

OBJECTIVE

To describe ameloblastoma of the jawbone in young Jamaicans, with special emphasis on radiological findings, and to introduce a radiological classification which could assist in the categorization of these cases according to their biological behaviour and hence their subsequent surgical and medical management.

SUBJECTS AND METHODS

The series comprised all the 18 cases of ameloblastoma of the jaw seen in patients under the age of 20 years in the two major hospitals in Jamaica with an oral and maxillofacial surgery department from 1980 to 1995. Radiological and histological diagnosis was confirmed in all. A case of maxillary ameloblastoma in a 13-year old girl seen in the year 2000 was also included in this study. This last case had special attributes.

RESULTS

All 19 patients had primary lesions of ameloblastoma. The mean age was 16.1 years with a mode of 18 years and a range of 13 to 19 years. The male to female ratio was 1.1:1. Eighteen cases were seen in the mandible and one case in the maxilla. Of these, 42% were unilocular and 58% were multilocular radiologically. Thirty-two per cent of cases had unerupted teeth associated with the lesions and 32% had root resorption. Based on our new radiological classification, the most predominant radiological type was IIb2 with root resorption (42%). There was no radiological type classically simulating dentigerous cyst (Ia2).

CONCLUSION

Ameloblastoma in young Jamaicans presented more in the adolescent period and are predominantly unicystic and rare in the maxilla. A new classification for ameloblastoma based solely on radiological presentation is adopted.

Maternal mortality following the use of misoprostol

Three cases of maternal death following the use of misoprostol are presented. In two of the cases the drug was used to procure illegal abortion, and in the third case maternal death occurred following uterine rupture, after misoprostol was used clinically for induction of labour. A brief review of the usage of misoprostol is presented, including recommendations for its safe use.

Severe aplastic anaemia--complete response to antilymphocyte globulin and cyclosporin

Severe aplastic anaemia is uniformly fatal unless treated with immunosuppressive therapy or bone marrow transplantation. The latter is curative in 65% of patients and is the treatment of choice in children and young adults. Antilymphocyte globulin (ALG) and cyclosporin may be used successfully in the absence of an HLA matched sibling donor. We report the case of a twelve-year-old boy with severe aplastic anaemia who received immunosuppressive treatment with ALG and cyclosporin and is alive and well three years and six months post treatment.

High rates of paraquat-induced suicide in southern Trinidad

The suicide rate in Trinidad and Tobago is much greater than that of its English-speaking Caribbean neighbors. Many of these suicides are paraquat induced. This research reviewed the deaths due to suicide in the area with the greatest agricultural activity in Trinidad for 1996 and identified, for further demographic and etiological investigation, cases in which paraquat was ingested as the agent of suicide. Of 48 cases of suicide for the year, 39 (81.3%) were due to paraquat poisoning. The incidence of paraquat-induced suicide was 8.0 per 100,000. Among the males, 47.8% were in the age group 25-34 (p < 0.001), and among the females 50.0% were in the 15-24 age group (p < 0.05). Family-of-origin disputes were the most frequently cited precipitant, followed by marital problems. Individuals of East Indian origin accounted for 89% of the suicide victims (p < 0.001). When compared with suicide by other methods in the country, these findings confirm that paraquat poisoning is a significant means of suicide in Trinidad and that young East Indian individuals are particularly vulnerable.

Homicide by paraquat poisoning

We report on two cases of homicide by paraquat poisoning. Both cases occurred in children and the common clinical presentations were gastrointestinal ulceration and acute respiratory distress, with pneumomediastinitis. Bullous emphysema was a common autopsy finding. Physicians and pathologists should be aware of these findings, for they are almost diagnostic of acute paraquat poisoning.

Forensic analysis of acute fatal poisonings in the southern districts of Trinidad

A prospective autopsy study was undertaken at General Hospital in San Fernando, Trinidad, to analyze deaths that occurred from poisoning during 1996 and 1997. During that period 105 deaths occurred from acute poisoning. The major poisons used were: paraquat (80 cases), organophosphate/carbamate insecticides (10 cases), and anti-psychotic drugs (6 cases). Much less frequently, battery acid, ETHREL[Ethephon; (2-chloroethyl)phosphonic acid], phenols, ethanol, kerosene and flavine were the agents of choice. Suicide accounted for 99 (94.29%) deaths. Of these, 44.44% occurred in the 10-29 y-age-group. Ingestion of paraquat seems almost always fatal, since the large volumes ingested make treatment universally ineffective. Aspiration pneumonitis (100% of cases), and pneumothorax with pneumomediastinum (18.75% of cases), were remarkable autopsy findings in those dying from paraquat poisoning, while asphyxia due to respiratory paralysis was the mode of death from pesticide ingestion. Efforts to prevent suicide by poisoning may be more useful than treatment protocols.

Acute myocarditis following Tityus trinitatis envenoming: morphological and pathophysiological characteristics

The clinicopathological features of four cases of scorpion envenoming by Tityus trinitatis are presented. The cardiac histopathology is recorded in the two fatal cases. The pathology of the acute myocarditis was a mixed picture of a toxic myocarditis and coagulative myocytolysis. These cardiac lesions are also seen in catecholamine induced cardiotoxicity and lend support to the theory that an adrenergic surge follows scorpion envenoming. A brief review of scorpion envenoming syndrome is undertaken in the light of these findings.

Fatal cardiac toxicity temporally related to poly-drug abuse

An 18-y-old male suffered sudden cardiac death following the use of cocaine, cannabis and ethanol. The pathophysiology of cardiac toxicity temporally related to the use of cocaine, cannabinoids and ethanol is reviewed.

Cardiac involvement with lymphoma/leukemia: a report of three autopsy cases

The clinicopathological findings in two patients with ATL and one patient with promyelocytic Leukemia affecting the heart are described. All three cases tested positive for HTLV-I while one of the ATL cases was also positive for HIV. Cardiac infiltrate in the ATL cases varied from microscopic focii in one case to macroscopic infiltration mimicking myocardial infarction in the other case. There were microabscesses in the myocardium in the case afflicted with promyelocytic Leukemia. All three cases had extensive malignant disease with multiple organ infiltration. There was no ante-mortem manifestation of cardiac involvement in any case. The cardiac dimensions were all within the normal range. The possible pathophysiology of cardiac involvement with Lymphoma/Leukemia is discussed.

Fatal metastatic calcification in a patient with HTLV-1-associated lymphoma

Metastatic calcification of the heart, lungs and kidneys is described in a 42-year-old male who had an HTLV-1-associated lymphoma. This fatal complication of HTLV-1-associated lymphoma has been infrequently reported, and the case in question is the first to be recorded in the Caribbean, where HTLV-1 is common. Aggressive therapy of hypercalcaemia should be instituted early in its genesis in these lymphomas, so as to avoid its fatal outcome.

Screening for HTLV-1 in healthy blood donors in Trinidad and Tobago, West Indies

Of 1089 healthy blood donors screened for HTLV-1 using ABBOTTS HTLV-1 EIA: 18 (1.7%) were positive; and 16 (1.5%) were confirmed positive using HTLV-1/11 Cambridge Biothec Western Blot method. HTLV-1 antibodies were found amongst the major ethnic groups, viz. Africans, 11 cases (68.75%) and East Indians 4 cases (25%). The mean age of the donors who tested positive for HTLV-1 was 30.75 years; and the male to female ratio was 4.3:1.

Suicide by poisoning

An epidemiological evaluation was conducted on 270 patients who died at the General Hospital, Port-of-Spain after presenting with deliberate self-poisoning between January, 1986 and June, 1990. The cause of death was confirmed by autopsy and toxicological analysis. Epidemiological variables of age, sex, race, precipitating factors and types of poison used were assessed. It was found that the male to female ratio was 2.7:1. East Indians accounted for 54.4%, Africans 42.0%, people of mixed ethnic origin 3% and Caucasians 0.6%. The majority of cases (52.6%) were seen in the age group 11-34 years. "Lovers' quarrels" (35.4% of cases), psychiatric illness (27.8% of cases) and family disputes (27% of cases) were reported as the most frequent precipitating events in suicide. East Indians predominated in those suicides precipitated by "lovers' quarrels" and family disputes, accounting for 63.2% and 58.9% of these cases, respectively; while for those suicides in which psychiatric illnesses were the main precipitating event. Africans were represented by 53.3% and East Indians 45.3%. Depression was the most common psychiatric illness diagnosed. Paraquat was the most popular poison used in 63.7% of the suicidal cases, and other agrochemicals were used in 20% of cases.

Diabetes mellitus and Klebsiella pneumoniae liver abscess in adults

Klebsiella pneumoniae hepatic abscess in five diabetic patients is reported. The recognition of a possible association between diabetes mellitus and pyogenic hepatic abscess, especially solitary ones, is highlighted. The clinical presentation including metastatic complications and the need for early diagnosis and institution of therapy are emphasized. Needle aspiration under ultrasonography is advocated and culture for anaerobes is stressed.

Spontaneous pneumothorax in acute paraquat toxicity

Spontaneous pneumothorax as a presenting feature of acute paraquat toxicity is as yet unreported. A review of the literature has shown that there has been one reported case of spontaneous pneumothorax occurring after paraquat toxicity. In this case, the pneumothorax occurred seven years after ingestion of paraquat (Nakaoka et al, 1987). The two cases of paraquat ingestion presented in this report are associated with spontaneous pneumothorax in the acute phase. A proposed mechanism for the development of the pneumothorax is discussed.

Pulmonary embolism as a cause of death

To investigate the present status of pulmonary embolism as the cause of death in a general hospital population, the author reviewed 610 autopsy reports, and associated hospital records for the period 1985-1989. Pulmonary embolism was the major contributing factor to the cause of death in 61 (10%) of the 610 autopsies performed. Of the patients dying from major pulmonary embolism, in only 12 (19.7%) was the diagnosis suspected antemortem; and in 44 (72%) deep vein thrombosis was detected in the femoral-popliteal vein at autopsy. The mean age of patients dying from major pulmonary embolism was 52.2 years, and 31 (50.8%) victims were under the age of 50 years. Fifty-six (92%) of patients dying from pulmonary embolism were of African descent while 5 (8%) were of East Indian descent. Without autopsies. 49 (80.3%) patients dying of pulmonary embolism would have been incorrectly certified and registered in death statistics based on clinical certification only.

Ectopic pregnancies in Trinidad. A clinico-pathological study of 154 consecutive surgically treated cases

A prospective study was conducted during the period August 1, 1985 to July 31, 1986 from ten hospitals in Trinidad and Tobago to determine the incidence and aetiology of ectopic gestations. One hundred and fifty-four cases of ectopic gestations were diagnosed in 153 patients, during the period of study, with eight patients having a previous ectopic gestation. The incidence of ectopic gestation was 9.02 per 1,000 births. Ectopic pregnancies were more common in women of African descent (64.29%) as compared to East Indian women (27.27%) and were most often seen in the 21 to 35-year-old age group where they accounted for 72.07% of the total. There were 16.23% ectopic gestations in the 36 to 42-year-old age group. Fifty-six per cent of the ectopic gestations occurred in the right fallopian tube. Ninety-one per cent were ruptured and 80.13% had histological evidence of chronic salpingitis. The maternal mortality from ectopic gestations was 1.3%. One primary ovarian ectopic gestation (0.65%) and one twin ectopic pregnancy were seen during the period of study.

Sudden cardiac death caused by coronary ostial compression by an aneurysm of the sinus of Valsalva

A 22-year-old man was asymptomatic until he died suddenly after being startled. Post-mortem examination was normal except for aneurysmal dilatation of the left Sinus of Valsalva, the upper margin of which formed a flap-like ridge, partially occluding the ostium of the left main coronary artery which arose immediately above it. Further compression of this "slit-like" orifice by aneurysmal distention was the proposed cause of myocardial ischaemia and arrhythmic death.