Periodontal pocket clearance by gamma scintigraphy in human volunteers.

BACKGROUND: With the interest in the delivery of drugs to the periodontal pocket has come an increased need to determine the loss of formulations from the site of application. In this respect, gamma scintigraphy has been used to measure formulation clearance in mucosal sites such as the oesophagus, nose and eyes by assessing the persistence of an incorporated radiolabel. However, the technique has not been used to follow clearance from the periodontal pocket. AIMS: The aim of this study was therefore to assess the potential of gamma scintigraphy to follow the loss of 2 contrasting formulations. 10% chitosan gel and normal saline. METHOD: Technitium-99m was used as the radionuclide and was incorporated into the formulations on the day of use. 9 subjects contributed up to 2 pockets for each formulation with probing depths > or = 5 mm. RESULTS: The results demonstrated that gamma scintigraphy was able to follow the loss of the radiolabel despite the small volumes of formulation placed in situ. The mean (SD) times (min) for the original counts to decline to 10%, 50% and 90% of the original values were: T10: chitosan 74.5 (59.0), saline 40.3 (21.1), T50: chitosan 41.5 (34.1) saline 20.8 (11.7) and T90: chitosan 8.5 (10.8), saline 1.4 (3.7) respectively. Clearance times of the 2 formulations were significantly different from each other (p<0.05). CONCLUSION: In conclusion, gamma scintigraphy is a sensitive method for assessing clearance from the periodontal pocket, and further studies are merited to optimise the use of the technique.

Can biochemical markers predict bone loss at the hip and spine?: a 4-year prospective study of 141 early postmenopausal women.

A number of recent studies have suggested that non-invasive measures of bone turnover are associated with bone loss at the forearm in postmenopausal women. Whether bone turnover markers are predictive of bone loss from the clinically important sites of lumbar spine and femoral neck remain unclear, and was the aim of this 4-year prospective study. One hundred and forty-one normal, postmenopausal women (mean age 52.0 +/- 3.3 years, mean menopause duration 20.4 +/- 5.7 months) were recruited for the study in 1988. Fasting early morning samples of blood and urine were collected at the baseline visit and stored at -20 degrees C prior to analysis. Serum was assayed for osteocalcin, oestradiol, oestrone, oestrone sulphate, testosterone, sex hormone binding globulin, dehydroepiandrosterone sulphate and total alkaline phosphatase. Urine was assayed for calcium, hydroxyproline, oestrone glucuronide and the collagen cross-links pyridinoline and deoxypyridinoline using high-performance liquid chromatography. Bone density was measured at the lumbar spine and femoral neck using dual photon absorptiometry at time 0, 12, 24 and 48 months. The mean annual percentage change in bone density (SE) was -1.41% (0.18) at the lumbar spine and -0.86% (0.22) at the femoral neck. There was no evidence of bimodality or a fast loser subgroup as the rates of change were normally distributed. Both simple and multiple stepwise regression analyses revealed no significant correlation between the rates of change in bone density with any biochemical marker, either individually or in combination, despite the study having sufficient power (80%) to detect a correlation of 0.5 between any biochemical marker levels and bone loss. We conclude that single measurements of these markers of bone turnover and endogenous sex hormones appear unlikely to be clinically useful in predicting early postmenopausal bone loss from either the spine or the hip.

The response of 99Tcm-methylene diphosphonate and 99Tcm-hexametazime-labelled neutrophils to intra-articular steroid injection in rheumatoid arthritis.

The synovial and bone uptake of tracer in the knees of patients with rheumatoid arthritis (RA) was quantified using 99Tcm-hexamethyl propylene amine oxime-labelled leucocytes and 99Tcm-methylene diphosphonate (MDP), respectively. Significant neutrophil migration and MDP uptake occurred in the knees of patients with RA irrespective of the disease duration. In all but one patient neutrophil migration was reduced after intra-articular steroid injection. The change in MDP uptake after steroid injection was variable. There was a significant correlation between the percentage reduction in neutrophil migration and pain score, while the latter correlated poorly with the change in MDP uptake. The quantification of the neutrophil component of the inflammatory process is a sensitive index for monitoring RA activity and response to pharmacological interventions, while quantitative bone scintigraphy should not be employed to monitor changes in joint inflammation in patients with RA.

In vivo leukocyte migration in arthritis.

We quantitated in vivo migration of neutrophils into the knees of patients with rheumatoid arthritis (RA) and osteoarthritis, using 99mtechnetium-hexamethyl-propylene-amineoxime-labeled leukocytes and gamma scintigraphy. Significant neutrophil migration occurred in patients with RA irrespective of disease duration, and it was reduced by 60% following intraarticular steroid injection. The reduction in neutrophil migration correlated with reduction in pain. Leukocyte migration into osteoarthritic joints was also demonstrated, although it was much less than that seen in rheumatoid joints. No significant leukocyte migration into the joints of patients without arthritis was demonstrated. This technique appears to provide a sensitive method for quantitatively assessing the neutrophil component of inflammation in individual joints of patients with arthritis.

99Tcm-labelled leucocyte imaging in active rheumatoid arthritis.

A simplified technique of labelling leucocytes with technetium-99m is described and applied to patients with active rheumatoid arthritis. The clinically active and less active knees in seven patients were imaged and the uptake of labelled leucocytes was measured. The measurements were repeated after local steroid injection into nine painful knees. A 50-80% reduction in leucocyte uptake localized to the region of the synovium was demonstrated in the eight knees which showed clinical responses and a rise of 8% in the non-responder. There was a variable response in the knees that were not injected. 99Tcm leucocyte imaging in rheumatoid arthritis is able to assess objectively joint inflammation and its response to treatment.

Dynamic scanning defines a colonic defect in severe idiopathic constipation.

A technique is described in which a chemical stimulus applied to the mucosa of the right colon is used to assess colonic motor function. Peroral intubation of the right colon was achieved using a fine polyvinylchloride (PVC) tube. Bisacodyl was used to initiate colonic motor activity, and colonic transit was monitored using 99mTc-DPTA and a gamma camera. In normal subjects there was rapid movement of the radiopharmaceutical from the right colon to the rectum. In patients with severe idiopathic constipation, a spectrum of colonic abnormality was observed from slow transit involving the rectum and sigmoid only to slow transit involving the whole colon. The hepatic flexure to rectum transit time for the 'head of the isotope column' in normals ranged from 1-10 minutes (mean 5.3 minutes), whereas in patients the transit time was 14-25 minutes in four patients and radioisotope did not reach the rectum by two hours in three other patients (controls v patients, p less than 0.01). Patients also showed relatively impaired transport of the isotope 'mass'. This technique has shown that the normal colon is capable of rapid effective transport in response to a standard stimulus, and that patients with severe idiopathic constipation have a definable colonic motor disorder.

Measurement of gastric emptying rates by radioactive isotope scanning and epigastric impedance.

When liquids of low electrical conductivity enter the stomach the impedance of the epigastric region to a 4 mA, 100 kHz current increases. There follows a decline, which logically represents gastric emptying. This method of measuring gastric emptying was compared against scintigraphy in six volunteers, and similar results were obtained. Impedance monitoring is entirely noninvasive, inexpensive, simple, and quick. The method merits further exploration.