Equivalency study of histological responses to complete or partial pulpotomies in inflamed baboon immature first permanent molars.

UNLABELLED: Partial pulpotomy is an accepted treatment for traumatised incisor teeth with exposed pulps. Clinical studies in humans suggest that this may also be an acceptable technique for carious exposed pulps in molar teeth, but objective histological evidence to support this perception is lacking. OBJECTIVE: To compare histological responses to complete or partial pulpotomies of inflamed pulps in immature baboon first permanent molar teeth. METHODS: An experimental study in the baboon (Papio ursinus). Pulpitis was induced with fresh Streptococcus mutans placed into occlusal cavities with a small pulpal exposure in 34 first permanent molars of 9 juvenile baboons. After 14 days a pulpotomy, either complete or partial, was performed on the same molars in contra-lateral quadrants using calcium hydroxide covered with IRM and amalgam. After 90 days specimens were harvested and examined under the light microscope with the examiner blind to the treatment. RESULTS: Reaction frequencies in the complete and partial pulpotomy teeth were: dentine bridges 9/16 and 10/16, viable pulp in root canals 10/16 and 13/18, peri-apical abscesses 3/13 and 4/13. Fisher's exact probability test showed no statistically significant rates between the groups. CONCLUSIONS: Complete or partial pulpotomy of inflamed pulps in immature baboon first permanent molars produced comparable reactions.

Zinc oxide-eugenol and calcium hydroxide pulpectomies in baboon primary molars: histological responses.

AIM: To compare histological responses to zinc oxide-eugenol (ZOE) and calcium hydroxide (CH) pulpectomies in primary molar teeth with inflamed pulps. STUDY DESIGN: This was an experimental study in 17 juvenile baboons (Papio ursinus). METHODS: Pulpitis was induced with fresh human carious dentine or Streptococcus mutans placed into occlusal cavities in 78 primary molars; after 14 days a pulpectomy was performed on the same primary molars with the two root fillings randomly allocated. The root canal openings were then covered with IRM and the cavity filled with amalgam. After 90 days specimens were harvested and examined under the light microscope with the examiner blind to the treatment. RESULTS: Reaction frequencies in the ZOE-treated versus CH-treated teeth were: no recognisable pulp 89% and 82%, internal root resorption 0% and 1%, external root resorption 11% and 24%, presence of bacteria 5% and 18%, periapical abscesses 24% and 52%. STATISTICS: Fisher's exact probability test showed a statistically significant higher prevalence of periapical abscesses in the CH-treated group (P=0.03, relative risk 2.2). CONCLUSIONS: ZOE pulpectomy is preferred to CH for the treatment of infected pulps in primary molars.

Pulpitis induction in baboon primary teeth using carious dentine or Streptococcus mutans.

The objective of this equivalency study was to see if a colony of Streptococcus mutans placed into cavities in primary molar teeth produced pulpitis similar to an established pulpitis induction method using carious dentine. In two juvenile baboons (Papio ursinus), occlusal cavities were cut in all 16 primary molar teeth, followed by making a small pulpal exposure after which the cavity was swabbed with 37 per cent phosphoric acid. In one half of the teeth, fresh soft human carious dentine was placed over the pulpal exposure; in the remaining teeth the exposure was covered with a colony of Streptococcus mutans in agar. All the cavities were restored with unlined light-cured composite resin. After 14 days specimens were harvested and examined under the light microscope with the examiner blind to the induction method. In both groups of teeth there was recognisable pulp, hyperaemia, micro-abscesses in the pulp and peri-apical abscesses. Reactions to soft caries were more severe than to Streptococcus mutans. The results show that Streptococcus mutans placed in a cavity with an exposure produces comparable pulpitis to fresh soft human carious dentine in the same type of cavity and that both methods produce pulpitis suitable for testing pulpotomy or pulpectomy treatments.

Bonding agents: adhesive layer thickness and retention to cavity surfaces with time.

This study assessed bonding agent thickness, cover and the influence of long-term storage on bonding agent retention to enamel and dentine surfaces in cut occlusal cavities in 46 human molar teeth. Two specimens were etched and set aside. The remaining specimens were divided into two equal groups and treated with either Optibond or Scotchbond Multipurpose Plus (SMPP) up to the adhesive stage. Thereafter two specimens from each group were stored for 0, 1, 3, 7 and 14 days and 1, 2, 3, 6 and 12 months in 1% NaCl. After storage the cavity surfaces were examined in a scanning electron microscope (SEM) and scored as to bonding agent cover. One specimen from each treatment was then embedded in resin, two sections prepared midway through each cavity, polished and re-examined in the SEM to measure bonding agent thickness at 13 sites along the cavity surface. Both bonding agents showed highly variable and significant (P < 0.05) bonding agent cover and layer thickness according to cavity site, SMPP more so than Optibond. Pooling of SMPP adhesive was apparent in cavity angles. Mean film thickness was significantly different between Optibond (221 +/- 130 microns) and SMPP (118 +/- 106 microns). There was no significant difference in bonding agent thickness between long- and short-term storage.

How does zinc oxide-eugenol compare to ferric sulphate as a pulpotomy material?

This study compared the clinical and radiographic responses after 3 months to a sterile compression technique with zinc oxide-eugenol or 15.5% ferric sulphate in 145 pulpotomised primary teeth in 30 children. In both groups of teeth the success rate was 100%. These short-term results suggest that either technique may be used.

First observation of self-amplified spontaneous emission in a free-electron laser at 109 nm wavelength

We present the first observation of self-amplified spontaneous emission (SASE) in a free-electron laser (FEL) in the vacuum ultraviolet regime at 109 nm wavelength (11 eV). The observed free-electron laser gain (approximately 3000) and the radiation characteristics, such as dependency on bunch charge, angular distribution, spectral width, and intensity fluctuations, are all consistent with the present models for SASE FELs.

Comparison of a short examination procedure with an extensive diagnostic protocol for the diagnosis of temporomandibular disorders.

Eighty-nine patients who complained of temporomandibular disorders were examined using a short and long examination procedure. Seventy were females and 19 males. Mean age of the group was 31.53 years, with a range from 11 to 73 years. The agreement between the two examination procedures was tested using the Kappa statistic. This gave a value of 0.876 (P<0.001). This allowed rejection of the hypothesis that the agreement found between the two procedures was due to chance alone.

Expression of the cyclin kinase inhibitor, p27kip1, in developing and mature human kidney.

It has been shown that glomerular visceral epithelial cells (VEC) proliferate during glomerulogenesis, but differentiated VEC of the fetal kidney do not. It is also recognized that the proliferative capacity of the VEC in mature kidneys is very limited, and according to some investigators, may be completely absent. The basis for this remains unknown. Cell proliferation is controlled by cell cycle-related proteins, of which one class, the cyclin kinase inhibitors (CKI), cause cell cycle arrest and inhibit proliferation. A role for CKI in kidney development is not known. Accordingly, we examined the expression of the CKI p27kip1 (p27) in developing and mature human kidney tissue. Concomitant expression of markers of cell proliferation, Ki-67-related antigen (Ki-67) and proliferating cell nuclear antigen (PCNA), also were examined in fetal and mature human kidney tissue by immunocytochemical techniques. In developing kidney, Ki-67 and PCNA expression are most pronounced in the nephrogenic zone where expression correlates inversely with increasing glomerular maturation. In well-differentiated glomeruli, Ki-67 and PCNA expression is present in some parietal epithelial cells but is absent in the VEC. In contrast, p27 staining exhibits a reverse gradient of expression. p27 is absent in the proliferating tissue exhibiting the earliest stages of differentiation, whereas expression is widespread in the differentiated epithelial cells of more mature glomeruli, in which detectable cell proliferation has ceased. Expression of p27 was not identified in fetal mesangial or glomerular endothelial cells. In the mature human kidney, the pattern of p27 expression identified in differentiated fetal glomeruli persists and appears to be constitutive and specific for glomerular VEC. This pattern of p27 expression in terminally differentiated VEC may explain their limited proliferative capacity in response to injury. This is the first demonstration of a potential role for p27 in human renal development.

Shear bond strength of amalgam and gallium alloys to dentine.

The purpose of this in vitro investigation was to determine the shear bond strength of admixed (Dispersalloy), irregular (Oralloy) and spherical (Lojic) amalgams, as well as an admixed gallium alloy (Galloy) to superficial, buccal, human dentine surfaces, using the Scotchbond Multi-Purpose Plus system. The bonds were stressed to failure in an Instron testing machine after 48 hours, and the following values (MPa) were obtained: Admixed = 7.74 +/- 0.7; Irregular = 9.47 +/- 1.4; Spherical = 9.82 +/- 2.4; Galloy = 11.03 +/- 2.5. Data were statistically analysed and fracture sites examined in a scanning electron microscope. Galloy demonstrated a statistical significant higher shear bond strength than to the other types of amalgams (p < 0.01).

Acute fluoxetine overdose: a report of 234 cases.

Limited toxicity information is available in the medical literature on the antidepressant fluoxetine (Prozac, Dista Products Co, Indianapolis, IN). The goal of this prospective multicenter study was to develop a toxicity profile of initial signs and symptoms observed in an acute fluoxetine overdose. A prospective study was made of patients reported to one of four American Association of Poison Control Centers' regional poison control centers after ingesting an acute overdose of fluoxetine. A standard data collection form was used on all patients ingesting fluoxetine. Information obtained included age, current medications, dose, coingested drugs, presenting symptoms, vital signs, electrocardiogram abnormalities, outcome, and fluoxetine levels. The authors collected 272 cases; 234 cases met the criteria of the study. Fluoxetine was ingested alone in 87 cases and with ethanol or other drugs in the remaining 147 cases. Of the 87 cases where fluoxetine was ingested alone, 67 patients were adults and 20 were children. Symptoms that were seen in the adult group included: tachycardia (15/67), drowsiness (14/67), tremor (five/67), vomiting (four/67), or nausea (four/67). Thirty patients did not develop symptoms. Twelve of the adult overdose patients had total fluoxetine levels ranging from 232 to 1390 ng/mL. The authors conclude that symptoms that develop after an acute overdose of fluoxetine appear minor and of short duration. Aggressive supportive care is the only intervention necessary.

Elevated 25-hydroxy and normal 1,25-dihydroxy cholecalciferol serum concentrations in a successfully-treated case of vitamin D3 toxicosis in a dog.

A 4-y old, 27 kg spayed female German Shepherd dog was observed to ingest one 1-oz package of a rodenticide containing cholecalciferol. An initial serum calcium concentration of 15.7 mg/dl was successfully reduced to normal during 10 d using calcitonin and prednisolone. During that time, the serum 25-hydroxy and 1,25-dihydroxy cholecalciferol concentrations ranged from 637 to 315 ng/ml (normal 32 +/- 6 ng/ml) and 64 to 29 pg/ml (normal 34 +/- 19 pg/ml), respectively. Serum mid-molecule parathyroid hormone concentrations (76 to 97 pcmol/L) were within the normal range (85-140 pcmol/L). These data indicate that hypercalcemia seen in dogs following field exposures to cholecalciferol-containing rodenticides may be associated with elevated 25-hydroxy rather than 1,25-dihydroxy cholecalciferol. Consequently, serum 25-hydroxy cholecalciferol concentrations may be the most conclusive method for diagnosing hypervitaminosis D3 toxicosis in the live dog.

Soft tissue effects of the holmium-YSGG laser in the canine trachea.

A holmium-yttrium scandium gallium garnet laser is a pulsed mid-infrared crystalline laser (wavelength, 2.1 microns), which is easily transmissible through flexible quartz fibers. With use of a 300-microns fiber delivery system, this laser was applied in the canine trachea to create a standard 5-mm diameter lesion through mucosa and submucosa. Power settings of 400 mJ and 600 mJ per pulse at 2 pulses per second were used, and wound healing was studied over a 2-week period. Excellent control of depth of tissue ablation was noted, with uncomplicated wound repair. Although healing was somewhat slower compared with healing when the CO2 laser was used, less granulation and fewer inflammatory changes were noted. Further studies need to be performed to determine ideal laser dosimetry before this laser is applied clinically.

The effects of fluoxetine in the overdose patient.

Fluoxetine (Prozac) is a new antidepressant, first marketed in the United States in January 1988. Only limited toxicologic information during a fluoxetine overdose is available. The goal of this prospective multi-center study was to develop a toxicity profile of initial signs and symptoms observed in fluoxetine overdose. A standardized data collection form was used on all patients ingesting fluoxetine as reported to four poison centers. Information obtained included age, dose, co-ingested drugs, presenting symptoms, vital signs, EKG abnormalities and lab values. Of the 127 cases of acute fluoxetine overdose collected, 106 cases met the criteria of the study. Of these, 69/106 ingested other drugs, including ethanol and 37/106 ingested fluoxetine alone. Of the latter group, the amounts ingested ranged from 20 to 1500 mg. It was observed that 48.6% (18/37) remained asymptomatic, 16.2% (7/37) were sleepy, 24.3% (9/37) had a sinus tachycardia (of 100 beats per minute or greater), and 8.1% (3/37) had a diastolic pressure over 100 mm Hg. Data collection is ongoing. Based upon our initial experience, fluoxetine in overdose appears to be relatively benign.

Teaching models for Nd:YAG laser bronchoscopy.

A number of groups have demonstrated the efficacy of neodymium:yttrium-aluminum-garnet (Nd:YAG) laser bronchoscopy for treatment of patients with selected tracheobronchial disorders. This therapy involves a new technology, the laser, and new adaptations of conventional rigid and flexible bronchoscopy that are unfamiliar to many bronchoscopists. We describe two teaching models for laser bronchoscopy that have been employed successfully in our laser courses. Using these models, bronchoscopists can become familiar with laser bronchoscopic equipment and appreciate the interaction of laser and soft tissue in a controlled setting in the laboratory before applying this therapy to patients.

New microspot micromanipulator for carbon dioxide laser surgery in otolaryngology. Early clinical results.

A new micromanipulator with microspot capability has been developed for carbon dioxide laser surgery in otolaryngology. The instrument features new infrared optics, which provide smaller laser spot sizes than those achievable with conventional micromanipulators (300 micron using a 400-mm operating microscope lens). The conventional red helium-neon aiming laser is replaced with a nonlaser fiberoptic image, and a power defocus control on the joystick manipulator eliminates external defocus controls. Less surrounding tissue trauma occurs with this new instrument by using a higher power density with average power settings of 1 to 2 W for cutting and ablation of tissue. Eight patients with benign laryngeal disease and one patient with dysplastic changes of the vocal cord were treated successfully without complications.

CNS depression in an infant after the ingestion of tobacco: a case report.

An 8-month-old female infant was brought in after ingesting cigarette butts. Upon presentation to the ED approximately 2.5 hr post-ingestion, the child was very lethargic and respirations were depressed. She was intubated and a NG tube was placed. Gastric lavage was performed, after which activated charcoal and sorbitol were given. Atropine was administered to treat excessive secretions. The patient became progressively more obtunded throughout the emergency department stay. Upon admission to the PICU she was minimally responsive. The urine tox screen was positive only for nicotine. The patient gradually improved with supportive care and was sent home on the third hospital day. Although the effects of Nicotine are well documented, few cases have been reported of severe toxicity in pediatric patients. We believe this to be the only reported case of severe CNS depression secondary to the ingestion of cigarette butts in a pediatric patient.

Gastric mucosal dissection using the Nd-YAG laser synthetic sapphire crystal contact probe. Development of an endoscopic method for the treatment of pancreatic pseudocysts.

A canine gastric-ulcer model was developed to evaluate the safety and effectiveness of the neodymium yttrium-aluminum-garnet (Nd-YAG) laser synthetic sapphire crystal contact probe in intraluminal gastric dissection. The purpose of the study was to assess the potential endoscopic application of the Nd-YAG contact probe in cystogastrostomy for the treatment of selected patients with pancreatic pseudocyst. Seven dogs were used in the study. In the first two dogs, full-thickness linear incisions through the gastric wall demonstrated the Nd-YAG contact probe could be used for a full-thickness gastrostomy dissection. In the other five dogs, gastric ulcers were created by injection of morrhuate sodium (5%). Gastric mucosal dissection with the Nd-YAG contact probe was performed without difficulty. Hemostasis was obtained with either the Nd-YAG contact probe or noncontact fiber, and all areas of dissection and ulcer beds healed within 35 days. The Nd-YAG laser contact endoscopic delivery system appears to be a promising technique for intraluminal dissection.