Influence of topical application of chlorhexidine on chronic gingivitis and gingival wound healing in the dog

Abstract— The present study examines the effect of topically applied chlorhexidine gluconate on chronically inflamed gingiva and standardized gingival wounds. Five beagle dogs were fed a soft "gingivitis inducing" diet for a period of 5 months. Subsequently, a 2 % chlorhexidine solution was applied daily for 42 days to the left molars, premolars, and canines of three dogs, the corresponding teeth in the right quadrants serving as controls. The degree of gingivitis, plaque, gingival exudation, and number of crevicular leukocytes were assessed on days 0, 11, 28, 35, and 42. The healing after gingival biopsy was studied in two dogs using the same parameters on days 0, 4, 7, 14, 28, and 42. In one of the dogs chlorhexidine was applied daily to the teeth and gingiva; the other dog had saline treatment. Biopsies for histologic examination were obtained at the beginning and the end of the experiment. From these criteria, it was shown that one daily topical application of 2 % chlorhexidine gluconate to the teeth and gingiva of the dog removes plaque and resolbes a well-established chronic gingivitis. It is concluded that in the dog it is passible through topical applications of chlorhexidine to establish and maintain a plaque- and gingivitis-free dentition.     

Quantitative assessment of urea,glucose and ammonia changes in human dental plaque and saliva following rinsing with urea and glucose

The rates of three processes associated with the rise and fall in plaque pH, that normally occur following a urea rinse, were determined: (i) disappearance of urea from plaque, (ii) disappearance of urea from saliva and (iii) formation and disappearance from plaque of the ammonia produced by the plaque bacteria from the urea. Also examined were two processes associated with the fall and rise in pH following a glucose rinse: the disappearance of glucose from plaque and from saliva. Entry into plaque of either urea or glucose during rinsing was immediate; the subsequent disappearance of both from the plaque was slow and followed first-order kinetics. The ammonia formation and urea-disappearance results suggested that clearance of urea from the plaque occurred mainly by bacterial degradation and not by diffusion out of the plaque. The rate constants for ammonia formation and for its subsequent disappearance from the plaque made it clear why a rapid rise and a slow subsequent fall in the pH occurs after urea rinsing. The rate constants enabled calculation of the ammonia produced as a percentage of the urea utilized. Only 16–26 per cent of the urea was recovered as ammonia and the remainder of the urea-N was stored probably as NH₂ moieties of certain amino acids. Such storage may enable the plaque bacteria to maintain the pH at an elevated level for an extended period of time by bacterial production of ammonia from these stored compounds after the urea ceases to be available as a source of substrate.     

Primary brain tumors treated with steroids and radiotherapy: low CD4 counts and risk of infection

PURPOSE: Patients with primary brain tumors are often treated with high doses of corticosteroids for prolonged periods to reduce intracranial swelling and alleviate symptoms such as headaches. This treatment may lead to immunosuppression, placing the patient at risk of life-threatening opportunistic infections, such as Pneumocystis carinii pneumonia. The risk of contracting some types of infection may be reduced with prophylactic antibiotics. The purpose of this study was to determine the occurrence of low CD4 counts and whether monitoring CD4 counts during and after radiotherapy (RT) is warranted. METHODS AND MATERIALS: CD4 counts were measured during RT in 70 of 76 consecutive patients with newly diagnosed Grade III and IV astrocytoma and anaplastic oligodendroglioma treated with corticosteroids and seen at the Johns Hopkins Hospital. Weekly CD4 measurements were taken in the most recent 25 patients. Prophylactic trimethoprim-sulfamethoxazole (160 mg/800 mg p.o. every Monday, Wednesday, and Friday) or dapsone (100 mg p.o. daily) in those with sulfa allergy was prescribed only if patients developed a low CD4 count. Carmustine chemotherapy wafers were placed at surgery in 23% of patients, evenly distributed between the groups. No patient received any other chemotherapy concurrent with RT. RESULTS: CD4 counts decreased to <200/mm3 in 17 (24%) of 70 patients. For the 25 patients with weekly CD4 counts, all CD4 counts were >450/mm3 before RT, but 6 (24%) of 25 fell to <200/mm3 during RT. Patients with counts <200/mm3 were significantly more likely to be hospitalized (41% vs. 9%, p <0.01) and be hospitalized for infection (23% vs. 4%, p <0.05) during RT. Overall survival was not significantly different between the groups. All patients with low CD4 counts were treated with prophylactic antibiotics, and no patient developed Pneumocystis carinii pneumonia. No patients developed a serious adverse reaction to antibiotic therapy. The mean dose of steroids, mean minimal white blood cell count, and number of patients treated with Gliadel wafers were not significantly different between the groups. CONCLUSION: The results of this study have confirmed the clinical impression that the use of high-dose corticosteroids and RT in patients with primary brain cancer is sufficient to result in severe immunosuppression and place these patients at risk of life-threatening opportunistic infections. A protocol of prophylactic antibiotics for those at risk may help prevent a potentially fatal side effect of treatment. A prospective study is underway to determine the frequency, depth, and prognostic implications of this finding.     

Discovery of Novel Insulin-Like Growth Factor-1 Receptor Inhibitors with Unique Time-Dependent Binding Kinetics

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Number and timing of antenatal HIV testing: Evidence from a community-based study in Northern Vietnam

Background  

HIV testing for pregnant women is an important component for the success of prevention of mother-to-child transmission of HIV (PMTCT). A lack of antenatal HIV testing results in loss of benefits for HIV-infected mothers and their children. However, the provision of unnecessary repeat tests at a very late stage of pregnancy will reduce the beneficial effects of PMTCT and impose unnecessary costs for the individual woman as well as the health system. This study aims to assess the number and timing of antenatal HIV testing in a low-income setting where PMTCT programmes have been scaled up to reach first level health facilities.     

Circadian pattern of intubation rates in ED patients with congestive heart failure

Purpose

A previous study showed that pulmonary edema patients presenting between noon and 4 pm have the highest rates of myocardial infarction and death. We hypothesized that the highest intubation rates would also occur at these times.

Basic Procedures

We performed a retrospective cohort study of consecutive patients seen by emergency department physicians in 15 hospital emergency departments (1996-2003).

Main Findings

Of 3.6 million visits in the database, 39,795 (1.1%) patients had congestive heart failure. We found statistically significant circadian variations in intubation rates. Patients arriving between midnight and 4 am had the highest intubation rates (4.1%), and those arriving between noon and 4 pm had the lowest (1.2%) (difference, 2.9%; 95% confidence interval, 2.4%-3.4%; P < .0001).

Conclusion

We found significant circadian variation in intubation rates, with a marked increase around midnight. Pathological mechanisms causing patients with congestive heart failure to require intubation may differ from those resulting in myocardial infarction or death.