Distribution of Cd and Zn levels in soils and Acacia xanthophloea Benth. from Lake Nakuru National Park Kenya.

Cadmium and zinc from anthropogenic sources in Lake Nakuru were investigated. High metal levels (mg/kg) in soils (Cd < or = 16.3 and Zn < or = 280) and Acacia xanthophloea (Cd < or = 32 and Zn < or = 310) were observed at polluted sites. Significant variations in metal values were evaluated using ANOVA (F test) and student's t test at p < 0.05 and metal correlations studied. High levels of metals in soils and unhealthy/dying Acacia were obtained at polluted sites. Significant positive correlation was obtained between Cd and Zn in soils and plants. Acacia sp are effective biomonitor of environmental quality in areas subjected to pollution.

Hormonal control of bone collagen synthesis in vitro. Effects of insulin and glucagon.

The direct effects of porcine insulin and glucagon on bone collagen and non-collagen protein synthesis have been examined in cultures of calvaria obtained from 21-day fetal rats. Bones were incubated for 24 to 96 h and [3H]proline was added for the last 2 h of culture. Incorporation of the label into collagenase-digestible protein (CDP) and noncollagen protein (NCP) was determined using purified bacterial collagenase. Insulin increased the labeling of CDP by 60 to 115% at concentrations of 10(-9) to 10(-6) M. A smaller stimulatory effect was observed on NCP. The effect on CDP appeared after 12 to 24 h of culture, was maintained for 96 h in the continuous presence of the hormone, but was lost within 3 h of removal of insulin from the culture medium. Insulin appeared to have a direct effect on collagen synthesis and not on collagen breakdown. Insulin did not affect the incorporation of [3H]uridine or [3H]thymidine into the RNA and DNA fractions of bone at 24 h. Insulin opposed the inhibitory effects of parathyroid hormone and dibutyryl cyclic-3',5'-adenosine monophosphate and to a lesser extent, the inhibitory effect of isobutylmethylxanthine on the labeling of CDP. Glucagon did not affect the response to insulin and by itself had small and variable inhibitory effects on proline incorporation.

Hormonal control of bone collagen synthesis in vitro: effects of parathyroid hormone and calcitonin.

The effects of parathyroid hormone (PTH) on bone collagen synthesis were assessed in organ cultures of fetal rat calvaria by measuring the incorporation of [3H]proline into collagenase-digestible (CDP) and non-collagen protein (NCP) using purified bacterial collagenase. 1) PTH decreased the incorporation of labeled proline into CDP at concentrations similar to those which stimulate bone resorption in vitro. 2) This effect was observed in bones treated for 6 h, but not for 3 h; it was maximal at 24 h and was maintained for 96 h. Bones treated with PTH for 48 h and transferred to control media for 48 h showed recovery of CDP labeling to control values. 3) the effect was specific for bone collagen. There was little alteration in the incorporation of proline into NCP, and incorporation into collagen was not inhibited. 4) The effect could be ascribed to decreased collagen synthesis and not to changes in amino acid uptake, precursor pool size, or degradation of newly synthesized CDP. In 3 hour experiments, PTH did increase the labeling of CDP and NCP, but only at tracer concentration of proline in the medium, compatible with an early stimulation of amino acid uptake. 5) Similar inhibition was observed with purified bovine (1-84) PTH and synthetic bovine PTH (1-34) as well as with crude homologous PTH obtained from rat parathyroid gland culture fluid. Human (hCT) and salmon (sCT) calcitonin did not inhibit the effect of PTH on the labeling of CDP nor did they stimulate CDP labeling directly at concentrations which inhibited bone resorption. Dibutyryl cyclic-3',5'-adenosine monophosphate (D3cAMP) inhibited labeling of CDP at concentrations of .03 to .3 mM, thus mimicking the action of PTH. However, in this system DBcAMP inhibited 45Ca release, thus mimicking CT. We conclude that the direct effect of PTH on bone collagen synthesis is a slow reversible inhibition, not opposed by CT. This effect may be mediated by cAMP formation in bone cells.

Management of post-traumatic temporomandibular joint ankylosis in children: case report.

Temporomandibular joint (TMJ) ankylosis is a distressing affliction that denies the victim the benefit of normal diet, careers that require normal speech and causes severe facial disfigurement that aggravates psychological stress. Opinions in current literature portray controversy in its management. Hurried clinicians take shortcuts and partially treat symptoms and often make the condition worse. Others ignore shortcomings and erroneously prescribe their preferred techniques as absolute indication to the peril of the affected children. Gap arthroplasty if applied in a growing maxillofacial skeleton as in children, causes iatrogenic arrest of facial growth. The intended correction of facial disfigurement is therefore not achieved. Early detection and immediate psychological support by excision and reconstruction of ankylosed TMJ with a costochondral graft, improves patient comfort and rehabilitation when used as a planned part of a comprehensive therapy. This paper questions prior varied opinions and discusses scientific baseline considerations in management of long standing TMJ ankylosis in children in relatively affordable circumstances.

Replacement therapy utilising autotransplanted wisdom teeth.

Loss of 1st and 2nd molars among adolescents due to dental caries is not uncommon in developing countries. Whilst their replacement is indicated, conventional methods of treatment, namely, bridging and dentures are in most cases inaccessible because of prohibitive cost. Given that it is in the same age group that diagnosis of unfavourably embedded wisdom teeth becomes feasible, autotransplantation of the latter to replace the unsalvageable 1st and 2nd molars could be an alternative treatment. Available literature suggests a success rate of over 82% based on follow-up studies of over ten years. Observations at the Dental School Clinic of the University of Nairobi, Kenya, indicate that the time it takes the transplant to 'take' and assume its functional position is 4 to 8 weeks and 2.5 to 3.5 months respectively. Since the method is relatively straightforward, we are of the view that training undergraduates and practising dental surgeons in this technique should enhance utilisation of otherwise "useless" teeth to replace the lost 1st and 2nd molars in occlusal rehabilitation.