Ceramic and non-ceramic hydroxyapatite as a bone graft material: a brief review.

Treatment of dental, craniofacial and orthopedic defects with bone graft substitutes has shown promising result achieving almost complete bone regeneration depending on product resorption similar to human bone's physicochemical and crystallographic characteristics. Among these, non-ceramic and ceramic hydroxyapatite being the main inorganic salt of bone is the most studied calcium phosphate material in clinical practices ever since 1970s and non-ceramic since 1985. Its "chemical similarity" with the mineralized phase of biologic bone makes it unique. Hydroxyapatite as an excellent carrier of osteoinductive growth factors and osteogenic cell populations is also useful as drug delivery vehicle regardless of its density. Porous ceramic and non-ceramic hydroxyapatite is osteoconductive, biocompatible and very inert. The need for bone graft material keeps on increasing with increased age of the population and the increased conditions of trauma. Recent advances in genetic engineering and doping techniques have made it possible to use non-ceramic hydroxyapatite in larger non-ceramic crystals and cluster forms as a successful bone graft substitute to treat various types of bone defects. In this paper we have mentioned some recently studied properties of hydroxyapatite and its various uses through a brief review of the literatures available to date.

Acute immune thrombocytopenic purpura triggered by insect bite.

Idiopathic Thrombocytopenic Purpura (ITP) is a blood disorder characterized by an abnormal decrease in the number of platelets in the blood. Acute thrombocytopenic purpura is most commonly seen in young children, with a sudden onset, following a viral illness, vaccination or an insect bite. The report is a rare case of ITP, which was triggered by a honey-bee bite and caused continuous intermittent bleeding from the gingival sulcular region of the maxillary left permanent first molar, and ecchymotic spots on the forehead, scalp, and lower limbs. A complete hemogram revealed severe thrombocytopenia with platelet count as low as 15,000/mm3. The patient was immediately hospitalized and administered platelet replacement and medication. With this report, the authors, as dentists, emphasize the significance of recognition, early diagnosis, and referral of such patients with bleeding disorders to specialized centers, for prompt treatment.

Epidemiology of rotavirus diarrhoea in children under five years in Bahrain.

A case-control study in children under five years of age was undertaken in Bahrain between February 1984 to March 1986 to study the aetiology of diarrhoea with special reference to rotavirus. During this period fecal samples were collected from 698 hospitalized and non-hospitalized diarrhoea cases and 532 from non-diarrhoea controls. Rotavirus was the enteropathogen most commonly detected (20.8%) and represented 68.7% of the total positives from the cases. Percentage rotavirus infection detected in the hospitalized patients was significantly higher than in non-hospitalized cases. Rotavirus was most frequently detected in the age group 6-11 months (26.6%). Rotavirus was not detected at all above 24 months of age. A higher percentage of rotavirus infection was noticed in males up to 11 months. Children of mothers with university education showed a higher level of rotavirus infection (39.3%) in comparison to children of mothers with school level education (20.4%) or no education (19.6%). Rotavirus was detected more often in patients from higher income homes (25.6%) compared to a lower income group (18.2%). No significant difference in rotavirus positivity was noticed between the children of working and non-working mothers. Rotavirus detection in relation to different feeding habits showed no difference. Rotavirus could be detected throughout the year from diarrhoea cases in Bahrain and showed no seasonal trend. It did not show any correlation with mean monthly temperature and mean monthly relative humidity.

Serum calcium level in patients with carcinoma of the cervix in relation to menstrual status.

Serum levels of calcium and phosphorous were evaluated in patients with carcinoma of the cervix between pre- and post-menopausal women and compared the same with various normal female populations of different physiological status, involving premenopause, postmenopause and third trimester of pregnancy. Hypercalcemia was noted both in premenopausal and postmenopausal cervix cancer patients although this is more marked in the latter. No definite relationship was observed between serum calcium and phosphorous (inorganic) level. The discordance in serum calcium level assumes significance in the light of hormonal status between the pre- and postmenopausal state of cancer patients.

Seroepidemiology of rubella in Bahrain.

Although the Ministry of Health of the State of Bahrain has set priorities for vaccination against a number of communicable diseases including the six target diseases of the Expanded Program of Immunization, no such policy for rubella immunization exists. The incidence of rubella in Bahrain is not precisely known nor is the magnitude of the problem of Congenital Rubella Syndrome. A survey of schoolchildren and primigravidae attending antenatal clinics was undertaken in Bahrain to determine the level of natural immunity against rubella in these groups, which we hope would help us in formulating a vaccination policy. We have found that 67.8% of the 6-7 year old children are susceptible to rubella and that by the age of 18 years susceptibility drops to 10.4%. The decrease in susceptibility was significant until the age of 14 years after which the change became minimal. Efforts should ideally be focused on immunizing all susceptible females before they get married. However, at present, it would be more economical to vaccinate all girls premaritally than to screen and vaccinate those susceptible. When a cheaper screening test for assessing immunity against rubella becomes available, a policy of premarital and post-partum screening followed by vaccination of susceptibles should be put into practice.

Cholera in Bahrain: epidemiological characteristics of an outbreak.

In the period 10 August 1978-23 January 1979, 913 culture-confirmed cases of cholera caused by Vibrio cholerae, biotype El Tor, serotype Ogawa, occurred in Bahrain. After discovery of the initial cases, others occurred sporadically, and the incidence reached a peak of 25-35 cases per day during the seventh week of the outbreak (16-22 September). The overall attack rate (27 per 10 000) was low and the outbreak subsided without mass immunization campaigns or rigorous border control of persons and imports. Investigation of 746 culture-confirmed cases that occurred in the period 10 August-13 October 1978, showed that cases occurred throughout most areas of the country and mainly affected infants, young children, and adult working-age males. Symptoms were very mild; fewer than 20% of patients required specific rehydration therapy. The highest attack rate (84 per 10 000) occurred in infants less than 1 year of age. No common vehicle or mode of transmission was identified. A matched-pair study of 35 cases and controls showed that adult cases were more likely than controls to have consumed food or beverage outside of the home before becoming ill. V. cholerae was isolated from stored drinking water in the houses of 8 cases but not from numerous samples of food and tap-water. It was presumed that cholera transmission occurred through a complex interaction of mild and asymptomatically infected persons with food, water, and the environment.

Bottle feeding as a risk factor for cholera in infants.

To determine risk factors for cholera in infants, a retrospective matched-pair study of 42 cases and their controls was undertaken during an outbreak of El Tor cholera in Bahrain in the autumn of 1978. The highest attack-rate of cholera (125/10 000) occurred in infants in the 6--11 month age-group, which corresponds to the weaning age in this community. Significantly more cases than controls were principally bottle fed (greater than 50% milk intake by bottle) than principally breast fed during the week before onset of illness (p=0.004). Analysis of various patterns of breast and bottle feeding did not determine whether the protection afforded by breast feeding was a negative effect (due to the lack of exposure to contaminated bottle feedings for breast fed infants) or a positive effect (due to protective functions of constituents of human breast milk). Cholera infection (with or without symptoms) among mothers of either case or control infants was uncommon (case mothers 3, control mothers 5), and mean serum vibriocidal and antitoxic antibody levels were similar for the two groups of mothers. These observations suggest that maternal infection did not affect the relative risk of infants having symptomatic cholera.