A 3- to 6-year study of overdentures supported by hydroxyapatite-coated endosseous dental implants

PURPOSE

The purpose of this study was to evaluate the clinical effectiveness of hydroxyapatite-coated cylindrical implants to support overdentures. These implants were placed between 1990 and 1994 and have been followed up over a period of 3 to 6 years.

MATERIALS AND METHODS

One hundred thirty-nine Calcitek dental implants were placed in 43 patients to support 14 maxillary and 30 mandibular overdentures. Standardized clinical review procedures were used.

RESULTS

At exposure all the implants were found to be osseointegrated. To date only 7 implants (5%) have completely failed and two associated overdentures (5%) have been lost. The cumulative survival rate of all implants over 6 years was 92%. However, if failure is defined by the loss of more than 4 mm of cervical bone, 33 implants could be classified as being in the process of failing. Using these figures, interval success rates as low as 82% were found by year 6, and the cumulative success rate would fall to 39%. Maxillary survival and success rates were significantly lower than mandibular rates, at 38% and 10%, respectively, by year 5.

CONCLUSION

Failure rates were higher in the maxillary arch, in poor quality bone, in smokers, and where implants were opposed by a natural dentition or an implant-supported prosthesis. The results suggest that the cervical bone level adjacent to the Calcitek cylindrical hydroxyapatite-coated implant failed to establish a steady state, particularly in the maxillary arch. Doubts remain regarding the long-term prognosis of these cylindrical implants.

Is surgical closure of patent ductus arteriosus a safe procedure in premature infants?

Despite indomethacin therapy, many premature infants require surgical closure of their patent ductus arteriosus (PDA). Between January 1985 and December 1997, 176 premature infants underwent surgical closure of PDA by vascular clip after failure of medical treatment. The median gestational age and birth weight were 26 weeks (range 23-36 weeks) and 847.5 g (range 400-2300 g), respectively. The median age at diagnosis and at surgery was 4 days (range, 1-37) and 21 days (range, 4-60) respectively. The median weight at surgery was 982.5 g (range 475-2740 g). Of these infants, 168 (95%) were intubated prior to surgery and the median time to extubation was 21 days (range 1-273 days). There were no operative deaths but 11 infants (6.4%) died from complications of prematurity (sepsis, bronchopulmonary dysplasia and pulmonary hemorrhage). The frequency of chest tube insertion at surgery decreased from 41.7% to 10% between the 1985-88 and 1996-97 periods (P<0.01). Three infants (1.7%) developed vocal cord paralysis directly related to the position of the vascular clip. Echocardiography confirmed PDA closure in 43 infants (24.4%) while the remaining 133 had no clinical signs of PDA. Surgical closure of PDA by vascular clip carries a very low morbidity in premature infants.

Pediatric cardiac surgery in the 1990s

Future developments in the repair of these complex anomalies will rely heavily on a complete understanding of present results, which can be achieved only with attention to detail and rigorous standards. Results must be continually updated and management changes carefully planned and then critically examined for significant differences. Thus, the day-to-day care of patients with congenital heart disease must withstand careful scrutiny, both for consistency and for end results.

Relatively low doses of cisapride in the treatment of nausea in patients treated with venlafaxine for treatment-refractory depression

Low doses of cisapride (5-10 mg twice daily) produced relatively rapid relief from nausea elicited by venlafaxine in six patients with treatment-refractory recurrent major depression. This further suggests that the nausea associated with serotonergic reuptake inhibition may be a result of 5-hydroxytryptamine (5-HT3) agonist action. No adverse cardiac experiences were encountered in spite of the potential interaction of cisapride with selective serotonin reuptake inhibitors at the cytochrome P4503A4 enzyme system.

Replantation of avulsed permanent teeth with avital periodontal ligaments: case report

Five maxillary anterior teeth lost during a grand mal epileptic seizure, were replanted using the technique recently described by Andreasen (1), after an extra-alveolar period of more than 72 h. The teeth were replanted surgically, 10 days after being avulsed, after they had been immersed in a 2.4% sodium fluoride solution and root filled with gutta-percha. Ankylosis was evident 3 months post-operatively. After 24 months there was evidence of considerable replacement resorption on the lateral incisors with little evidence of resorption on the other replanted teeth. Even though the long term prognosis is uncertain, this technique has an advantage of seeing the patient through the period of growth as well as maintaining the height of alveolar bone making possible the provision of an aesthetically acceptable prosthesis at a later age.

Clinical implications of depression in rheumatoid arthritis

The clinical implications of depression in the context of rheumatoid arthritis are described. An overview of the diagnostic criteria for depression is provided, with specific focus on major depression and the associated subtypes. The neurobiological literature on major depression is briefly reviewed and the implications of the depression literature for the care of persons with rheumatoid arthritis are discussed.

Achalasia mistakenly diagnosed as eating disorder and prompting prolonged psychiatric hospitalization

We have reported a rather extreme instance in which achalasia was misdiagnosed as a primary eating disorder. Our patient spent 2 months in a psychiatric institution before the correct diagnosis was made. Misdiagnosis in this case could have been avoided (1) if the symptoms of dysphagia had been elicited as part of her history, (2) if it had been recognized that the vomiting (her dominant symptom) was involuntary and not self-induced, (3) if the absence of disturbed body image had been appreciated, or (4) if it had been recognized that she did not meet accepted criteria for anorexia nervosa or bulimia. Our case and others like it in the literature also illustrate that achalasia frequently remains an elusive diagnosis.

Panic disorder in cardiology patients: a review of the Missouri Panic/Cardiology Project

This paper reviews current evidence from several cardiology populations that suggests that panic disorder is prevalent and underdiagnosed. Cardiology patients with atypical angina, and no heart disease have a high likelihood of having panic disorder, as suggested by studies of two separate cardiology populations. That they resemble psychiatric populations with panic is suggested by their positive response to alprazolam. A panic disorder subtype, called non-fear panic disorder also appeared in about one-third of these cardiology panic patients. These patients have most of the panic symptoms but do not report fear during their episodes.

Assessment of total head excursion and resting head posture

Clinicians typically evaluate head posture and cervical range of motion in both standing and sitting positions. There are currently few quantitative data available regarding resting head posture (RHP) or total head excursion (THE), a retraction-protraction gliding range of head motion in the sagittal plane, and where the RHP lies within THE. The purposes of this study were to describe quick and simple methods to determine quantitative measurements of THE, RHP while sitting, and RHP while standing, to provide preliminary data on these postural measurements for men and women in four age categories; and to determine the effects of gender and age on these measurements. Subjects included 218 able-bodied adults. Measurements of THE, RHP while sitting, and RHP while standing were taken. A two-way multivariate analysis of variance followed by two-way analyses of variance showed only the main effect of gender to be significant (p less than .05) for each of the dependent measurements. Across the age groups, men had a greater excursion distance from retraction to protraction than women. Within THE, women held their heads more forward than men. Men held their heads farther from the vertical than women while standing. These results indicate that normal head and neck posture is different for men and women and should not be judged by the same standard. The methods used in this study are clinically advantageous in that they produce objective, quantitative measurements of THE and RHP that may be obtained quickly and with minimal equipment.

Mitral valve prolapse, panic disorder, and chest pain

Mitral valve prolapse is a common cardiac disorder that can readily be diagnosed by characteristic auscultatory and echocardiographic criteria. Although many diseases have been associated with mitral valve prolapse, most affected individuals have the primary form of the disorder. Mitral valve prolapse is an inherited condition commonly associated with myxomatous degeneration of the mitral valve and its support structures. Complications of mitral valve prolapse, including cardiac arrhythmias, sudden death, infective endocarditis, severe mitral regurgitation (with or without chordae tendineae rupture), and cerebral ischemic events, occur infrequently considering the wide prevalence of the disorder. Panic disorder is a specific type of anxiety disorder characterized by at least three panic attacks within a 3-week period or one panic attack followed by fear of subsequent panic attacks for at least 1 month. It too is a common condition with a prevalence and age and gender distribution similar to that of mitral valve prolapse. Panic disorder and mitral valve prolapse share many nonspecific symptoms, including chest pain or discomfort, palpitations, dyspnea, effort intolerance, and pre-syncope. Chest pain is the symptom in both conditions that most commonly brings the patient to medical attention. The clinical description of chest pain in patients with mitral valve prolapse is highly variable, possibly reflecting multiple etiologies. Chest pain in panic disorder is usually characterized as atypical angina pectoris and as such bears resemblance to the chest pain commonly described by patients with mitral valve prolapse. Multiple investigative attempts to elucidate the mechanism of chest pain in both conditions have failed to identify a unifying cause. Review of the literature leaves little doubt that mitral valve prolapse and panic disorder frequently co-occur. Given the similarities in their symptomatology, a high rate of co-occurrence is, in fact, entirely predictable. There is, however, no convincing evidence of a cause-effect relationship between the two disorders, nor has a single pathophysiologic or biochemical mechanism been identified that unites these two common conditions. Until specific biologic markers for these disorders are identified, it may be impossible to do so. The lack of a proven cause-and-effect relationship between mitral valve prolapse and panic disorder and the absence of a unifying mechanism do not diminish the clinical significance of the high rate of co-occurrence between the two conditions. Primary care physicians and cardiologists frequently encounter patients with mitral valve prolapse and nonspecific symptoms with no discernible objective cause who fail to respond to beta-blockade. Panic disorder should be considered as a possible explanation for symptoms in such patients.(ABSTRACT TRUNCATED AT 400 WORDS)

Validating studies for panic disorder in patients with angiographically normal coronary arteries

This article describes validating studies for diagnosing panic disorder in some patients with angiographically normal coronary arteries (NCA) and chest pain. Psychiatric interviews of 94 such patients showed that 34% met the diagnostic criteria for panic disorder. Further studies showed that NCA patients with panic disorder were more disabled at 3.5-year follow-up, had more relatives with panic disorder, were more likely to suffer from major depression, and were more likely to respond to 35% CO2 challenge with panic symptoms. Because panic disorder is highly disabling but responds well to psychological and pharmacologic treatments, screening NCA patients in the cardiology population for this disorder is recommended.

The use of computed tomography in the management of facial trauma by British oral and maxillofacial surgeons

A survey of 184 British oral and maxillofacial surgeons on their use of computed tomography (CT) in the management of craniofacial trauma showed that the majority of the 116 surgeons who replied used this form of imaging for frontal, nasoethmoidal, and orbital fractures. Only 6% of respondents reported no advantage in CT imaging over plain radiography. The access to CT scanners and the value of the reports in the management of patients was rated as satisfactory by 75% of respondents, and a similar percentage reported that CT service was becoming increasingly available to their units.

Nonfearful panic disorder in neurology patients validated by lactate challenge

OBJECTIVE

Nonfearful panic disorder meets the DSM-III-R criteria for panic disorder but is not associated with subjective fear and anxiety. The authors determined its prevalence in a group of neurology patients and assessed its diagnostic validity as a panic disorder subtype by evaluating the response of the patients with nonfearful panic disorder to sodium lactate and antipanic pharmacotherapy.

METHOD

The subjects were all neurology patients referred over 1 year to a university hospital's psychiatric consultation service because of negative medical workups for their symptoms (N = 48). Patients who met the DSM-III-R criteria for panic disorder but did not report subjective anxiety or fear during panic episodes were diagnosed as having nonfearful panic disorder. Afterward, each of those patients received a sodium lactate infusion and, 5 hours later, a sodium chloride infusion. They were then treated with antipanic medication and followed for at least 6 months.

RESULTS

Of the 48 neurology patients referred for psychiatric evaluation, 11 (23%) met the criteria for panic disorder, and all 11 met the criteria for nonfearful panic disorder. All 11 responded positively to lactate but not to placebo, and they each experienced an at least 75% reduction in symptoms during the 6-month follow-up period. Detailed case reports of three of these patients are presented.

CONCLUSIONS

These findings support the construct and predictive diagnostic validity of nonfearful panic disorder as a subtype of panic disorder and suggest that a lack of attention to this group leads to both the underestimation of the prevalence of panic disorder and to the withholding of potentially successful treatments for this group.

Computed tomography in the diagnosis of maxillofacial trauma

A study of 34 patients who were investigated for maxillofacial trauma using high resolution computed tomography (CT) scanning is presented. The areas where this increasingly available technique offers more accurate information than conventional plain radiographs are discussed.

Thin section computed tomography in the evaluation of naso-ethmoidal trauma

We reviewed the computed tomography (CT) appearances, plain film radiographs and clinical findings of 17 patients who suffered fractures of the naso-ethmoidal complex. Six patients (35%) with diplopia were noted on CT to have lateral displacement of medial orbital wall fragments into the orbit (medial wall 'blow-in' fractures) leading to displacement of the globe or extra-ocular muscles. Medial displacement of ethmoid bone fragments (medial wall 'blow-out' fractures) with medial rectus entrapment was noted in a further two cases (11%) also. Multiple associated facial fractures were seen in all but one case with CT evidence of frontal bone fracture and intracranial injury in 12 (70%) patients. CT was judged to add valuable information to clinical findings and plain film radiography and was especially helpful where marked soft tissue swelling precluded detailed physical examination of the naso-orbital region. The CT features of naso-ethmoidal trauma are illustrated and discussed and the advantages of CT in the pre-operative evaluation of such injuries are emphasised.

Retrograde root filling using antibiotic-containing, radiopaque, bone cement

An investigation is reported on the in-vitro behaviour, characteristics and properties of three gentamicin-containing radiopaque bone cements that are considered to be promising retrograde root-filling materials. Three commercially available cements, CMW-1G, CMW-3G and Palacos R with gentamicin were studied with regard to bacteriocidal properties, tissue compatibility in cell culture, and ability to seal tooth cavities as evidenced by dye diffusion. Results were compared and contrasted with those obtained with an amalgam. The antibiotic-containing cements investigated are considered to have some distinct advantages over amalgam when used as retrograde root-filling materials in vitro. Amalgam was found to have poor bacteriocidal properties and poor tissue compatibility but slightly better apical sealing abilities than the cements. No apparent drawbacks were found with the cements.

Cyclic AMP-resistant mutants of S49 mouse lymphoma cells hemizygous for expression of regulatory subunit of type I cyclic AMP-dependent protein kinase

For use in studies of the functional organization of regulatory (R) subunit of type I cAMP-dependent protein kinase, 84 independent cyclic AMP-resistant mutants were isolated from sublines of S49 mouse lymphoma cells that are hemizygous for expression of the R subunit. Mutants were characterized by two-dimensional gel analysis of the R subunits, assays of kinase activation, and assays of cAMP-binding. All but eight of the mutants had kinases with increased apparent Kas for cAMP-dependent activation, and studies with site-selective cAMP analogs revealed considerable phenotypic diversity among these mutants. Forty-nine of the mutants had "charge-shift" lesions that mapped to regions of the R subunit polypeptide implicated in cAMP-binding. Twenty-five of the "charge-shift mutants" expressed only mutant R subunits, and the lesions in most of these isolates inhibited binding of cAMP to mutated cAMP-binding sites. The remainder of the charge-shift mutants expressed both mutant R subunit and R subunit with wild-type gel mobilities. The origin of these "heterozygous" mutants from parental "hemizygous" cells remains a puzzle.

Activation of type I cyclic AMP-dependent protein kinases with defective cyclic AMP-binding sites

Two S49 mouse lymphoma cell variants hemizygous for expression of mutant regulatory (R) subunits of type I cyclic AMP-dependent protein kinase were used to investigate functional consequences of lesions in the putative cAMP-binding sites of R subunit. Kinase activation properties of wild-type and mutant enzymes were compared using cAMP and six site-selective analogs of cAMP. Kinases from both mutant sublines were relatively resistant to cyclic nucleotide-dependent activation, but they were fully activable by at least some effectors. Relative resistances of the mutant kinases varied from about 5-fold for analogs selective for their nonmutated sites to as much as 700-fold for analogs selective for their mutated sites; resistance to cAMP was intermediate. Apparent affinities of wild-type and mutant R subunits for [3H]cAMP were not appreciably different, but competition experiments with site-selective analogs of cAMP suggested that binding of cAMP to mutant R subunits was primarily to their nonmutated sites. Analyses of cooperativity in cyclic nucleotide-dependent activation of mutant kinases, synergism between site I- and site II-selective analogs in activating the mutant enzymes, and dissociation of bound cAMP from mutant R subunits provided additional evidence that the mutations in these strains selectively inactivated single classes of cAMP-binding sites: phenomena attributable in wild-type enzyme to intrachain interactions between sites I and II were always absent or severely diminished in experiments with the mutant enzymes. These results confirm that R subunit sequences implicated in cAMP binding by homology with other cyclic nucleotide-binding proteins actually correspond to functional cAMP-binding sites. Furthermore, occupation of either cAMP-binding site I or II is apparently sufficient for activation of cAMP-dependent protein kinase. The presence of four functional cAMP-binding sites in wild-type kinase enhances the cooperativity and sensitivity of cAMP-mediated activation.

Phosphorylation of regulatory subunit of type I cyclic AMP-dependent protein kinase: biphasic effects of cyclic AMP in intact S49 mouse lymphoma cells

Intact S49 mouse lymphoma cells were used as a model system to study the effects of cyclic AMP (cAMP) and its analogs on the phosphorylation of regulatory (R) subunit of type I cAMP-dependent protein kinase. Phosphorylation of R subunit was negligible in mutants deficient in adenylate cyclase; low levels of cAMP analogs, however, stimulated R subunit phosphorylation in these cells to rates comparable to those in wild-type cells. In both wild-type and adenylate cyclase-deficient cells, R subunit phosphorylation was inhibited by a variety of N6-substituted derivatives of cAMP; C-8-substituted derivatives were generally poor inhibitors. Two derivatives that were inactive as kinase activators (N6-carbamoylmethyl-5'-AMP and 2'-deoxy-N6-monobutyryl-cAMP) were also ineffective as inhibitors of R subunit phosphorylation. Preferential inhibition by N6-modified cAMP analogs could not be ascribed simply to selectivity for the more aminoterminal (site I) of the two cAMP-binding sites in R subunit: Analog concentrations required for inhibition of R subunit phosphorylation were always higher than those required for activation of endogenous kinase; 8-piperidino-cAMP, a C-8-substituted derivative that is selective for cAMP-binding site I, was relatively ineffective as in inhibitor; and, although thresholds for activation of endogenous kinase by site I-selective analogs could be reduced markedly by coincubation with low levels of site II-selective analogs, no such synergism was observed for the inhibitory effect. The uncoupling of cyclic nucleotide effects on R subunit phosphorylation from activation of endogenous protein kinase suggests that, in intact cells, activation of cAMP-dependent protein kinase requires more than one and fewer than four molecules of cyclic nucleotide.

A prototype epithermal neutron beam for boron neutron capture therapy

An epithermal neutron beam has been designed and tested at the Georgia Institute of Technology's 5-MW Research Reactor. The prototype facility consists of aluminum and sulfur disks in a tangential beam port for fast neutron filtration. A cadmium sheet at the port exit removes the thermal neutrons from the transmitted beam, leaving an intensely epithermal neutron beam spanning five energy decades, each contributing to the flux demanded by boron neutron capture therapy. The thermal neutron flux generated by the incident epithermal neutrons in a polyethylene head phantom peaks at a depth of 3 cm and remains above the incident thermal flux to a 7-cm depth. The beam thus provides the penetration required for treating deep-seated gliomas. Photon contamination in the prototype facility is high, and a number of basic modifications are proposed for reducing it to safer levels.