Controlling biofilm and microbial contamination in dental unit waterlines

Despite the fact that the ADA had set the goal of less than 200 colony-forming units per milliliter of unfiltered output water from dental unit waterlines to be achieved voluntarily by the year 2000, there is much confusion and resistance within the profession with regard to waterlines. Many in the profession are still wondering what the most effective means are to predictably achieve the goal. It is a well-established fact that bacterial biofilm can readily form within dental unit waterlines and degrade the microbial quality of the water in dental units regardless of the water source. These biofilms are primarily formed by various microcolonies of bacteria that attach to surfaces over time within the waterlines. An increasing number of medically compromised and immunocompromised patients being treated in dental offices and increased public awareness have brought about renewed interest in this issue. There are generally four categories of products that are available to address this issue: independent water systems, sterile water delivery systems, filtration, and chemical treatment protocols. A recent study at the University of California at Los Angeles demonstrates that the Ultra chemical treatment protocol can be an effective means of controlling biofilm in dental unit waterlines.

Renal cortical calcification in syngeneic intact rats and those receiving an infrarenal thoracic aortic graft: possible etiological roles of endothelin, nitrate and minerals, and different preventive effects of long-term oral treatment with magnesium, citrate and alkali-containing preparations

Renal cortical nephrocalcinosis (C-NC) is a rare disorder of uncertain etiology. Using highly inbred (syngeneic) male Lewis rats, we describe the spontaneous occurrence of histologically detectable C-NC in sham operated control rats (Sham; n=12), its aggravation following grafting of the ascending thoracic aorta from a donor rat to the infrarenal aorta of a recipient (ATx; n=12), and differences in C-NC inhibition after 12 weeks of oral administration of magnesium (Mg), citrate and alkali. C-NC is characterized by Kossa-positive areas located in cells of the proximal tubule close to blood vessels and also, to a lesser extent, within glomeruli. After ATx there was vascular overproduction of endothelin (ET-1) but decreased production of nitrate; in renal cortical tissue there was an excess of calcium over Mg and phosphorus and oxalate over citrate. In plasma there was an increase in calcium and creatinine within the normal range. Calcification of tubular cells was eliminated by a preparation containing potassium, sodium and bases (from citrate degradation and bicarbonate) in addition to Mg. Less effective than the latter was Mg-potassium citrate and least effective, Mg citrate. The former treatment also normalized calcemia and urinary nitrate, but only incompletely suppressed ET-1 and had no significant effect on glomerular calcification or tissue and urinary oxalate. Urinary ET-1 excess appeared directly related to the cortical tissue calcium/Mg ratio, and urinary excretion of Mg, citrate and total protein appeared to be inversely related to the severity of C-NC. It was concluded that (1) the highly inbred rat is prone to precipitation of calcium phosphate in the renal cortex; (2) this type of C-NC occurs in close proximity to and within renal vascular tissue and is associated with an imbalance of vasoconstrictors and vasodilators of endothelial origin; (3) effective inhibition of C-NC can be achieved by an alkalinizing combination of Mg, potassium, sodium and citrate, underscoring its utility in the prophylaxis of pathological calcium phosphate deposition. The significance of these findings for the etiology and treatment of clinical disorders with renal and vascular calcification is uncertain and requires further investigation.

Respiratory acidosis

Respiratory acidosis, or primary hypercapnia, is the acid-base disorder that results from an increase in arterial partial pressure of carbon dioxide. Acute respiratory acidosis occurs with acute (Type II) respiratory failure, which can result from any sudden respiratory parenchymal (eg, pulmonary edema), airways (eg, chronic obstructive pulmonary disease or asthma), pleural, chest wall, neuromuscular (eg, spinal cord injury), or central nervous system event (eg, drug overdose). Chronic respiratory acidosis can result from numerous processes and is typified by a sustained increase in arterial partial pressure of carbon dioxide, resulting in renal adaptation, and a more marked increase in plasma bicarbonate. Mechanisms of respiratory acidosis include increased carbon dioxide production, alveolar hypoventilation, abnormal respiratory drive, abnormalities of the chest wall and respiratory muscles, and increased dead space. Although the symptoms, signs, and physiologic consequences of respiratory acidosis are numerous, the principal effects are on the central nervous and cardiovascular systems. Treatment for respiratory acidosis may include invasive or noninvasive ventilatory support and specific medical therapies directed at the underlying pathophysiology.

Supplementation with alkaline minerals reduces symptoms in patients with chronic low back pain

The cause of low back pain is heterogeneous, it has been hypothesised that a latent chronic acidosis might contribute to these symptoms. It was tested whether a supplementation with alkaline minerals would influence symptoms in patients with low back pain symptoms. In an open prospective study 82 patients with chronic low back pain received daily 30 g of a lactose based alkaline multimineral supplement (Basica) over a period of 4 weeks in addition to their usual medication. Pain symptoms were quantified with the "Arhus low back pain rating scale" (ARS). Mean ARS dropped highly significant by 49% from 41 to 21 points after 4 weeks supplemention. In 76 out of 82 patients a reduction in ARS was achieved by the supplementation. Total blood buffering capacity was significantly increased from 77.69 +/- 6.79 to 80.16 +/- 5.24 mmol/L (mean +/- SEM, n = 82, p < 0.001) and also blood pH rose from 7.456 +/- 0.007 to 7.470 +/- 0.007 (mean +/- SEM, n = 75, p < 0.05). Only intracellular magnesium increased by 11% while other intracellular minerals were not significantly changed in sublingual tissue as measured with the EXA-test. Plasma concentrations of potassium, calcium, iron, copper, and zinc were within the normal range and not significantly influenced by the supplementation. Plasma magnesium was slightly reduced after the supplemenation (-3%, p < 0.05). The results show that a disturbed acid-base balance may contribute to the symptoms of low back pain. The simple and safe addition of an alkaline multimineral preparate was able to reduce the pain symptoms in these patients with chronic low back pain.

pH changes in root dentin after root canal dressing with gutta-percha points containing calcium hydroxide

Alkalinizing action on root dentin was investigated by treating the enlarged root canals of a total of 120 extracted teeth for 24 h, 3 days, or 7 days with either gutta-percha points (size 40) containing calcium hydroxide or an equivalent quantity of aqueous calcium hydroxide suspension. After splitting the teeth longitudinally the pH of the dentin was determined using a pH microelectrode in small cavities at each of four set measuring points. The gutta-percha points were unable to alkalinize the root dentin over a period of 7 days. Clear, rapid, and prolonged alkalinization of the dentin extending through to the root surface was achieved, however, with the aqueous calcium hydroxide suspension.

Preventive dentistry for the general dental practitioner

Although the prevalence of dental caries has decreased gradually in the past three decades in the Australian population, dental caries remains the primary reason for tooth loss in Australia. At the community level, total health expenditure on the treatment of dental caries (and its consequences) is substantial. Accordingly, caries prevention is an important focus at both the individual and community levels. This paper outlines the principles upon which modern caries prevention is based and stresses the importance of manipulating the oral environment (in terms of salivary parameters, ions, pH and the oral flora) as a major strategy for effective long-term caries prevention. Practical advice is provided on the correct home use of preventive agents, including chewing gums, chlorhexidine, fluorides, bicarbonate rinses and phosphopeptides.

Metabolic acidosis in calves

In neonatal calves metabolic acidosis is a common sequela to diarrhea-induced dehydration and endotoxemia in the aftermath of gram-negative bacterial infections. Without treatment, metabolic acidosis is a prime factor in the death of many of these calves. This article begins with a general discussion about the causes and recognition of metabolic acidosis. The remaining sections detail the subjective and objective methods available to assess the severity of acidosis and treatment options for this metabolic condition.

Obstructive nephropathy due to sulfa crystals in two HIV seropositive patients treated with sulfadiazine

Two HIV seropositive patients receiving sulfadiazine for presumed cerebral toxoplasmosis who developed an obstructive nephropathy are described. Ultrasound examination showed respectively a bilateral hydro-ureteronephrosis in one patient and unilateral hydro-ureteronephrosis in the other. The obstructive nephropathy resolved in both patients with alkalic hydration and discontinuation of the sulfadiazine.

pH-dependent cocaine-induced cardiotoxicity

Severe cocaine toxicity causes acidemia and cardiac dysfunction. These manifestations are described in 4 patients who presented with seizures, psychomotor agitation, and cardiopulmonary arrest. Their initial laboratory values demonstrated acidemia and electrocardiographic findings that included a prolonged QRS complex and QTc duration and a rightward T40 ms axis deviation. Treatment of the patients with hyperventilation, sedation, active cooling, and sodium bicarbonate infusion led to the normalization of their blood pHs and reversal of their cardiac conduction disorders. Acidemia can contribute to cocaine cardiac disorders by promoting conduction delays, dysrhythmias, and depressed myocardial contractility. Good supportive care corrects the blood pH and cardiac conduction disorders and remains the major focus in the management of patients with cocaine toxicity.

Lidocaine in ultrasound-assisted lipoplasty

The doses of lidocaine used for lipoplasty often exceed what is commonly recommended for other surgical procedures. When using these high volumes of lidocaine and wetting solutions, a variety of safety issues must be considered. The author knows of no other plastic surgery operation in which the safety of the procedure is so influenced by the medications administered. Each component of the wetting solution--the alkalized fluid, the epinephrine, and the lidocaine--has an individual and interrelated role. The absorption of lidocaine with epinephrine after subcutaneous installation for lipoplasty probably represents a unique situation, and the concepts presented should not necessarily be extrapolated to other types of procedures.

Methemoglobinemia after axillary block with bupivacaine and additional injection of lidocaine in the operative field

Methemoglobinemia may occur after the administration of various drugs, including some local anesthetics. We report a patient with chronic renal failure and ischemic heart disease who developed clinically significant methemoglobinemia after an axillary block with bupivacaine and additional injection of lidocaine in the operative field. Although the two local anesthetics usually do not cause methemoglobinemia, we suspect that the displacement of lidocaine from protein binding by bupivacaine, in combination with metabolic acidosis and treatment with other oxidants, was the reason for the development of methemoglobinemia.

Contemporary urological intervention for cystinuric patients: immediate and long-term impact and implications

PURPOSE

We determined the immediate efficacy of contemporary urological intervention for cystine stones and the impact of such intervention on the subsequent rate of recurrent stone formation.

MATERIALS AND METHODS

A total of 31 cystinuric patients underwent selected intervention for 61 stone events. Patients were subsequently followed at 6 to 12-month intervals while being treated with standard medical therapy. Logistic regression models were used to correlate potential risk factors with the efficacy of the intervention in achieving a stone-free status. Kaplan-Meier estimates of the probability of recurrence-free survivals at 1 and 5 years were generated, and risk factors for stone recurrence were analyzed using the log rank test.

RESULTS

Overall stone-free rate was 86.9%, which was not significantly influenced by the initial stone burden or type of intervention selected. The probability of recurrence-free survival at 1 and 5 years was 0.73 and 0.27, respectively, and again this probability was independent of initial stone burden or type of intervention selected. Urinary cystine levels before intervention and post-procedure residual stone status also failed to impact significantly on the risk of recurrence. However, a stone-free result, in contrast to residual stones, prolonged the mean time to stone recurrence from 346 to 1,208 days.

CONCLUSIONS

While cystine stones are not amenable to all currently available minimally invasive therapeutic modalities, high stone-free rates can be achieved without the need for open surgery and as such cystinuric patients clearly benefit from contemporary intervention. When such intervention is used selectively, with consideration given primarily to stone burden and location, rates of recurrence will relate primarily to the natural history of the medically treated cystinuric patient, and not the type of intervention applied.

[Urologic management of cystine lithiasis in the upper urinary tract. Modalities and indications]

Cystine urinary stones is a relatively rare hereditary disorder of dibasic amino acid transport characterized by frequent recurrences. The management of these stones remains problematical despite the remarkable progress in the urological treatment of upper urinary tract stones. Cystine stones are particularly refractory to extracorporeal shock waves and relatively inaccessible to dye pulsed laser (504 nm). Apart from this exception, endourological techniques often represent the most appropriate therapeutic solution, but they are associated with significant morbidity. The physicochemical characteristics of these stones also allow dissolution by urinary alkalinization or the formation of disulfide compounds. In parallel with oral treatments, which constitute the basis of prevention of recurrence, dissolution can be obtained by direct perfusion of the urinary tract. This approach often requires irrigation for several weeks with a risk of the specific complications of catheterization, especially percutaneous catheterization. Prophylaxis, essentially consisting of dilution and dissolution of urinary cystine, raises the problem of the potential adverse effects of drug treatment. Cystinuria is easily detectable and can be investigated either systematically or only in the families concerned. However, the incidence as well as the frequently benign nature of cystinuria tend to limit its value and its indications.

[From the study of biochemical changes in ischemic and reperfused skeletal muscle to the controlled reperfusion of limbs in patients with acute severe ischemia]

The reperfusion of a limb which has been submitted to a severe and prolonged period of ischemia may be followed by dramatic local and systemic complications. The results of several experimental studies have given insights on the biochemical and physiopathological alterations occurring in the ischemic and reperfused skeletal muscle. Therefore the technique of the controlled limb reperfusion has been developed. we present the results obtained in two patients with this technique. Two patients were admitted for a limb-threatening ischemia consecutive to embolism. After removal of the thrombi with a Fogarty's catheter and before reperfusion with the normal blood, a controlled limb reperfusion was performed by mixing the systemic blood with a crystalloid solution in order to obtain a hyperosmolar, hypocalcemic, alcalotic and substrate-enriched (aspartate and glutamate) reperfusate. This reperfusate was infused during 30 min with a roller pump into the deep and superficial femoral arteries. The delivery conditions (temperature, flow and reinjection pressure) were closely monitored. In both cases, no post-operative complication was observed and the pedal pulses were restored after the operation. Complete recovery of the motor and sensitive functions were observed and the patient were discharged at the 10th post-operative day.

Perioperative management of pulmonary hypertension after heart transplantation in childhood

BACKGROUND

Pulmonary hypertension is responsible for a substantial part of perioperative and postoperative mortality and morbidity after cardiac transplantation. Treatment of right ventricular failure after increased pulmonary vascular resistance is difficult especially in infants and children. Therefore we started a preventive therapy of pulmonary hypertension after cardiac transplantation to avoid right ventricular failure and compared the results with a group of patients with conventional therapy.

METHODS

Group 1 (n = 13), with transplantation from 1988 to 1991, was treated with vasodilators when symptoms of right ventricular failure developed. Group 2 (n = 19) had preventive treatment with prostaglandin E1 (PGE1), the phosphodiesterase-III inhibitor enoximone, and alkalinazation starting during weaning from cardiopulmonary bypass.

RESULTS

Six patients in group 1 died; four of them as the result of right ventricular failure in the immediate postoperative course despite aggressive treatment. In group 2 there were three deaths as the results of rejection (2) and infection (1). None of these patients developed right ventricular failure (p = 0.02). Cold ischemic time, extracorporeal circulation time, and waiting time before transplantation were significantly longer in group 2. Side effects of this preventive therapy were not observed.

CONCLUSIONS

We conclude that prophylactic therapy of pulmonary hypertension with vasodilators in infants and children after heart transplantation is safe and effective in preventing right ventricular failure in the postoperative course.

Plasma potassium response after tromethamine (THAM) or sodium bicarbonate in the acidotic rabbit

The purpose of this study was to evaluate the plasma potassium (K+) response after administration of tromethamine (THAM) or sodium bicarbonate (NaHCO3) in an acidotic rabbit model. Eighteen healthy, adult female New Zealand White rabbits were subjected to severe hypoxia until a base deficit of -10 mEq/L resulted. Rabbits were then randomized to receive THAM solution, NaHCO3, or no drug (control). The drug was administered over 2 min in quantities calculated to correct a base deficit of 10 or greater. Plasma K+ and sodium (Na+) were measured for 45 min after drug administration. No difference in K+ response was noted after THAM, NaHCO3, or no drug. In contrast, THAM resulted in significantly lower Na+ concentrations when compared to the NaHCO3 or the control group (P < 0.05). In this rabbit model, alkalinization after THAM administration results in K+ changes similar to those after NaHCO3. THAM should be considered when treating acidosis in patients where hypernatremia is a concern.

Primary varicella-zoster-induced rhabdomyolysis

Acute rhabdomyolysis after uncomplicated, primary varicella-zoster infection is a rare condition that is sparsely reported in the literature. We report a case of acute rhabdomyolysis due to varicella-zoster infection and review the literature regarding the etiology, diagnosis, and management of this potentially life-threatening condition. Rapid recognition, along with appropriate treatment, should result in an excellent recovery without adverse sequelae.

Alkali therapy extends the period of survival during hypoxia: studies in rats

The goal of this study was to evaluate whether sodium bicarbonate might be a useful form of therapy for hypoxic L-lactic acidosis; our aim was to determine if alkali could extend the time of survival in this setting. Hypoxia was induced in anesthetized, paralyzed, artificially ventilated rats by lowering inspired O2 to 5.5%, an amount sufficient to develop a severe degree of L-lactic acidosis. Measuring arterial blood gases frequently permitted maintenance of a near-constant arterial O2 content. Three groups of hypoxic rats were studied: first, no infusions (n = 10); second, sodium bicarbonate at a rate equal to H+ production in the no-infusion group (n = 12); and third, a control for the Na load in the second group as NaCl (n = 17). Survival was close to twofold longer in the sodium bicarbonate group. Part of this beneficial effect seemed to be increased anaerobic glycolysis, producing ATP along with L-lactic acid. In addition, there was a large decrease in the metabolic demand (consumption of O2) in the 7- to 15-min period in the sodium bicarbonate group. Rats exposed to hypoxia and infused with NaCl for 15 min or alkali for 15, 27, or 40 min were then returned to room air; all survived for the subsequent experimental period of 150 min. We found that there is both a rationale and experimental evidence for giving sodium bicarbonate to prolong survival during hypoxia.

Effect of alkali therapy with NaHCO3 or THAM on cardiac contractility

We examined the impact of alkali therapy on myocardial contractility in a model of myocardial ischemia in dogs using direct measurements of myocardial contractile function. Myocardial ischemia in the left anterior descending (LAD) artery territory was induced using a perfusion circuit from the internal carotid artery to the LAD artery. Myocardial contractile function was assessed using sonomicrometry for measurement of percent systolic shortening (%SS), preload recruitable stroke work (PRSW) slope, and end-systolic pressure-length relationship (ESPLR) area. Because the blood flow in LAD artery was diminished by approximately 70%, there was a significant decrease in O2 delivery and uptake by the ischemic myocardium. Ischemia led to a significant fall in LAD regional contractile function with %SS decreasing from 15 +/- 2 to 7 +/- 2%, PRSW slope from 82 +/- 10 to 37 +/- 5 mmHg, and ESPLR area from 121 +/- 2 to 48 +/- 14 mmHg.mm (P < 0.05). In six dogs, the intracoronary administration of NaHCO(3) resulted in a significant increase in pH in LAD arterial and venous blood. There was, however, no significant increase in %SS (6 +/- 2), PRSW slope (43 +/- 10 mmHg), or ESPLR area (60 +/- 13 mmHg.mm). Since administration of NaHCO(3) resulted in a significant increase in PCO2 in LAD arterial and venous blood, similar experiments were carried out in five dogs, but with the intracoronary infusion of the amine buffer THAM [tris(hydroxymethyl)aminomethane (Tris) buffer; 2-amino-2-hydroxyl-1,3-propandiol] instead of NaHCO3. Although administration of THAM resulted in a significant increase in pH and a significant decrease in PCO2, in both LAD arterial and venous blood, there was no significant improvement in any of the parameters used to assess myocardial contractile function. In conclusion, administration of alkali (NaHCO3 or THAM) does not enhance the contractile function of the ischemic myocardium.