Search PubMed⌕ Search

Biomedical subjects

R D Jackson

Publications and source records attributed to R D Jackson.

At least 55 records · Page 3Linked to original sources
PubMed1993

Aesthetic inlays and onlays: a clinical technique update.

Advances in adhesive technology offer the dentist the potential to place tooth-reinforcing restorations with more conservative preparations. At the same time, improvements in tooth-colored restorative materials are yielding high levels of durability and aesthetics. The combination of these events has led to the development of an entirely new class of restorations for posterior teeth, called aesthetic bonded inlays and onlays. The learning objective of this article is to present an updated, simplified, and predictable technique for placing an indirect composite resin inlay or onlay.

Composite Resins↗
PubMed1992

Weight-training effects on bone mineral density in early postmenopausal women.

We tested the hypothesis that weight training would be an effective modality in maintaining or increasing bone mineral density (BMD) at the lumbar spine, femoral neck, and bone mineral content (BMC) at the distal wrist in early postmenopausal women. A total of 17 women completed a 9 month weight-training program, and 9 women served as a control group. Resistance training occurred three times per week using exercises designed to increase muscular strength. Mean change in lumbar BMD in the weight-trained group (1.6 +/- 1.2%, mean +/- SEM) was significantly different from the change in the control group (-3.6 +/- 1.5%, p less than 0.01) over the 9 month period. No significant weight-training effect was detected at the femoral neck or distal wrist site. We conclude that weight training may be a useful exercise modality for maintaining lumbar BMD in early postmenopausal women.

Bone Density↗
PubMed1992

Clinical effects of a 0.12% chlorhexidine rinse as an adjunct to scaling and root planing.

This trial tested the adjunctive effects of a 0.12% chlorhexidine rinse (Peridex) upon gingival healing following scaling and root planing. Assessments were made on reduction in plaque (Pl), gingivitis (GI), pocket depth and gingival bleeding as measures of treatment benefit. All subjects had Class II, III or IV periodontal conditions. Following baseline examinations, subjects received a gross supragingival scaling and polishing. Subjects were separated by sex and periodontal classification, arrayed by GI scores, and randomly assigned to either the chlorhexidine rinse or a placebo rinse. Subjects were instructed to rinse with 1/2 ounce of their assigned products for 30 seconds twice daily. Following two weeks of product use, the clinical examinations were repeated and two randomly selected, opposing contralateral quadrants were scaled and root planed. After two more weeks of product use (week 4), clinical examinations were repeated and the remaining quadrants were scaled and root planed. At week 6, final clinical examinations were conducted. Since half-mouths were treated at different times and exposed to the treatment rinses for different periods, the data were analyzed for the half-mouths independently 2 and 4 weeks after gross scaling, and 2 and 4 weeks after root planing. A total of 94 subjects (47 in each treatment group) completed all phases of the trial. Gingival healing following scaling and root planing in subjects using a chlorhexidine rinse (0.12%) was significantly better than subjects using the placebo rinse as evidenced by less gingivitis (29%), fewer GI bleeding sites (48%) and less plaque (54%).

Analysis of Variance↗
PubMed1991

Chronic use of the calcium channel blocker nifedipine has no significant effect on bone metabolism in men.

Calcium channel blockers have been reported to have such diverse effects on reduction in protein synthesis, diminished incorporation of proline into new collagen, and decreased hormone release in vitro. The chronic affect of the calcium channel blocker nifedipine was examined in vivo to determine the possible impact of pharmacologic calcium channel blockade on bone metabolism. Eleven Caucasian males treated with an average of 40 mg/d nifedipine for an average of three years were compared to 11 control males matched for age, height, weight, activity level, cardiovascular status, and calcium intake. No significant differences between groups were noted in bone mineral density at the lumbar spine (L2-4), proximal femur (femoral neck, Ward's triangle and trochanter), and proximal and distal radius. There were also no significant differences in parameters of bone turnover (alkaline phosphatase, osteocalcin, urine calcium/creatinine, and hydroxyproline/creatinine ratio), or hormones that might affect calcium metabolism and bone (testosterone, PTH, 25(OH) vitamin D, and calcitonin). In summary, chronic nifedipine use in males is not associated with either a beneficial or adverse effect on bone metabolism.

Adult↗
PubMed1990

Intermittent cyclical etidronate treatment of postmenopausal osteoporosis.

BACKGROUND: To determine the effects of etidronate (a bisphosphonate that inhibits osteoclast-mediated bone resorption) in the treatment of postmenopausal osteoporosis, we conducted a prospective, two-year, double-blind, placebo-controlled, multicenter study in 429 women who had one to four vertebral compression fractures plus radiographic evidence of osteopenia. METHODS: The patients were randomly assigned to treatment with phosphate (1.0 g) or placebo twice daily on days 1 through 3, etidronate (400 mg) or placebo daily on days 4 through 17, and supplemental calcium (500 mg) daily on days 18 through 91 (group 1, placebo and placebo; group 2, phosphate and placebo; group 3, placebo and etidronate; and group 4, phosphate and etidronate). The treatment cycles were repeated eight times. The bone density of the spine was measured by dual-photon absorptiometry, and the rates of new vertebral fractures were determined from sequential radiographs. RESULTS: After two years, the patients receiving etidronate (groups 3 and 4) had significant increases in their mean (+/- SE) spinal bone density (4.2 +/- 0.8 percent and 5.2 +/- 0.7 percent, respectively; P less than 0.017). The rate of new vertebral fractures was reduced by half in the etidronate-treated patients (groups 3 and 4 combined) as compared with the patients who did not receive etidronate (groups 1 and 2 combined) (29.5 vs. 62.9 fractures per 1000 patient-years; P = 0.043); the effect of treatment was most striking in the subgroup of patients with the lowest spinal bone mineral density at base line, in whom fracture rates were reduced by two thirds (42.3 vs. 132.7 fractures per 1000 patient-years; P = 0.004). The addition of phosphate provided no apparent benefit. There were no significant adverse effects of treatment. CONCLUSIONS: Intermittent cyclical therapy with etidronate for two years significantly increases spinal bone mass and reduces the incidence of new vertebral fractures in women with postmenopausal osteoporosis.

Aged↗
PubMed1990

Analysis of intentional head gestures to assist computer access by physically disabled people.

Any human-computer interface requires both a means of transducing information flowing from the person and a way of classifying this information in a form that can be used by an application program. Since several interface devices exploit the head movements of disabled people to control computers, this paper includes a discussion of existing technologies based on head movements. As an alternative to simple techniques based on pointing to classify this information, this paper studies the possibility of using a combination of pointing and movement gestures to control an application program. By using hidden Markov models to classify movements into 'yes', 'no' and spurious gestures, it was possible to control a simple graphics application program. Subsequent analysis showed that the hidden Markov models achieved a 74% success rate.

Adult↗
PubMed1990

The clinical effects of a mouthrinse containing 0.1% octenidine.

The purpose of this three-month clinical trial was to evaluate the effects of a 0.1% octenidine mouthrinse on plaque, gingivitis, extrinsic dental stain, and the oral soft tissues. A total of 451 adult volunteer subjects was initiated into the study and given baseline dental examinations. The subjects were stratified into two balanced groups according to gender, plaque, and gingivitis scores. The subjects then received a dental prophylaxis and were provided with dentifrice, toothbrushes, and either a mouthrinse containing 0.1% octenidine dihydrochloride as the active ingredient or a similar placebo mouthrinse. Subjects were instructed to rinse with their assigned product for 30 s twice each day. Examinations were repeated at six weeks (soft-tissue assessment, gingivitis) and three months (soft tissues, plaque, gingivitis, dental stain). The results showed that the group rinsing with 0.1% octenidine had significantly less plaque (39%), gingivitis (50%), and bleeding sites (60%) than the group using the control product, but had significantly higher stain formation and experienced longer prophylaxis times to remove the stain. The oral soft-tissue examinations revealed no differences in the groups in either the numbers or types of lesions noted.

Adolescent↗
PubMed1990

An esthetic, bonded inlay/onlay technique for posterior teeth.

In the past, the primary focus of dentistry has been on the alleviation of pain and stopping the progression of disease. The reduction in the prevalence of dental caries, along with advances in adhesive technology, have combined to revolutionize the practice of dentistry today. The modern dentist, using the latest available cosmetic techniques, is now able to satisfy the emotional wants and needs of patients. The public, well informed about the possibilities for anterior esthetics, now desire tooth-colored restorations in the posterior. A new heat- and pressure-curing resin inlay/onlay material and the clinical and laboratory technique for its use are discussed.

Acrylic Resins↗
PubMed1989

Persistence of large molecular weight prolactin secretion during pregnancy in women with macroprolactinemia and its presence in fetal cord blood.

Two hyperprolactinemic women with marked increases in circulating 150K PRL were studied from conception throughout pregnancy and delivery. The serum PRL increase during pregnancy in these women was considerably less than that in normal pregnant women (2- and 3.5-fold vs. 10- to 20-fold increases, respectively). The 150K PRL species persisted as the predominant circulating form of PRL throughout each trimester of pregnancy in these women. In contrast, the predominant form of PRL in serum from normal pregnant women was the 22K PRL form. Gel filtration analysis of the umbilical venous cord serum of infants of the macroprolactinemic women demonstrated excessive concentrations of 150K and 50K PRL compared to the molecular species of PRL in the cord serum of normal infants. Repeat analysis of the PRL species in one infant at age 3 yr continued to reveal excessive secretion of 150K PRL (11% vs. less than 6% in normals). These data suggest that genetic influences may be operative in determining PRL heterogeneity.

Adult↗
PubMed1989

Clinical effect of a sanguinaria dentifrice on plaque and gingivitis in adults.

A clinical trial was conducted to evaluate the effects of a sanguinaria-zinc chloride dentifrice on the prevention of plaque formation and gingivitis. A total of 59 young adults, 18 to 30 years of age, either performed supervised brushing with a 0.075% sanguinaria-0.05% zinc chloride dentifrice, a 0.24% sodium fluoride dentifrice, or rinsed daily with a 0.05% NaF solution. Clinical evaluations for plaque and gingivitis were performed after 7, 14, and 21 days of the test regimen. After 21 days, all subjects resumed twice daily supervised brushing and flossing and post-test evaluations were conducted after two weeks. The results showed that after 7, 14, and 21 days both groups using dentifrices had significantly less plaque and gingivitis than the group using the rinse, and there were no significant differences between the two groups using either the sanguinaria-ZnCl2 or the NaF dentifrices.

Adolescent↗
PubMed1989

Abnormal cortisol dynamics after traumatic brain injury. Lack of utility in predicting agitation or therapeutic response to tricyclic antidepressants.

A period of significant agitation affects up to 30% of patients after traumatic brain injury. The severity and persistence of this agitation may be such as to require pharmacologic methods as part of the treatment plan. To define which subgroup of patients develop severe agitation warranting intervention and to utilize the information to predict therapeutic responsiveness to tricyclic antidepressants (TCA), we examined cortisol dynamics in 35 traumatically brain-injured (TBI) patients 2-10 months post-TBI. Fasting hypercortisolemia (cortisol greater than 20 micrograms/dl) and/or an absent diurnal variation (1600:0800 cortisol greater than 0.5) was noted in more than 70% of TBI subjects. These abnormalities in cortisol dynamics were not predictive of severe agitation (chi 2 = 0, df = 1, P = 0.99 for hypercortisolemia; chi 2 = 0.163, df = 1, P = 0.7 for absent diurnal variation) and did not differ significantly between TCA responders and nonresponders. The cortisol response to dexamethasone suppression was abnormal (postdexamethasone cortisol value at 0800 and 1600 greater than 5 micrograms/dl) in 34 of 35 subjects and was also not predictive of the presence of agitation. The 0800 cortisol was lower in TCA nonresponders in comparison with TCA responders (8.3 +/- 5 v 17.2 +/- 9). In summary, severe TBI warranting inpatient rehabilitation results in hypothalamic-pituitary-adrenal dysfunction. The extent of these abnormalities renders the assessment of cortisol secretion of limited value in making clinical judgments concerning the development of post-traumatic agitation or the management of that agitation by tricyclic therapy.

Adolescent↗
PubMed1989

Orientation Group Monitoring System: an indicator for reversible impairments in cognition during posttraumatic amnesia.

During posttraumatic amnesia (PTA), confusion, attention deficits, impaired memory, disorientation, and inability to process external stimuli often preclude accurate assessment of subtle neurologic changes. The Orientation Group Monitoring System (OGMS) has proven to be a simple, useful strategy for assessing cognitive status. Retrospective analysis of weekly aggregate OGMS scores indicated that a decline in performance of 0.23 or greater is clinically significant. Over a one-year period, 27 patients demonstrated significant decrements in OGMS performance, and in 93% of these instances, the decrease was attributable to a medical problem. Adverse effects of medication was the most common etiology of decreased performance (n = 13). Overwhelmingly, the decline in the OGMS score was the first indication of impaired cognition. This monitoring device is therefore useful as an indicator during PTA of declining cognitive function, warranting further medical evaluation.

Adult↗
PubMed1988

Amitriptyline for post-traumatic agitation.

Agitated behavior is exhibited in up to 30% of patients recovering from a traumatic brain injury. Past treatment protocols have included proactive behavioral management and major tranquilizers. We now report the use of amitriptyline for control of agitation. For a period of over 2 years, 43 male and 15 female patients with a "recent" severe brain injury were admitted for inpatient rehabilitation and subjected to traditional structured programming for treatment of post-traumatic amnesia (PTA). In 20 patients, 18 men and 2 women, where agitation persisted sufficiently to impede rehabilitation despite initiation of structure, amitriptyline was instituted. These patients were of a comparable age (29.4 years for the agitated group versus 25.6 years for the nonagitated group), but the agitated patients had a lower median Rancho Los Amigos Hospital Level of Cognitive Functioning in a comparison to nonagitated patients (V versus VI). All patients were monitored for cognitive performance by the Orientation Group Monitoring System, and a daily account of frequency, severity and type of agitation was recorded. Within 7 days of initiation of therapy, 12 of 17 patients within PTA had dramatic decrease in agitation (5/5 patients at Rancho IV; 4/8 at Rancho V; 3/4 at Rancho VI). Two of the three patients at Rancho VII had agitation that was unresponsive to amitriptyline. The amitriptyline-responsive patients were maintained on the drug through PTA, and the Orientation Group Monitoring System scale demonstrated no impedance in cognitive recovery. Thus, amitriptyline appears most useful as an adjunct for treatment of nondirected agitation; it also has a role in reducing the severity of the directed agitation that is seen during but not after PTA.

Adolescent↗
PubMed1987

Sequential prolactin evaluation of a "cured" patient with recurrence of prolactinoma.

Several investigators have suggested that prolactin secretion in some subjects with hyperprolactinemia associated with pituitary macroadenomas may have a resistance to the prolactin inhibitory hormone, dopamine. This report describes a male subject with a prolactinoma whose preoperative evaluation demonstrated a resistance of prolactin release to inhibition by dopamine. Evaluation of prolactin secretion from monolayer culture of his tumor also revealed a resistance to inhibition by dopamine. Four months postoperatively, normal serum prolactin levels and a normal maximal inhibition of prolactin to a dopamine infusion of 0.04 microgram/kg/minute suggested surgical cure. However, a 24-hour prolactin sampling revealed blunted nocturnal augmentation of prolactin release, an early escape of inhibition of prolactin release at 150 minutes from a 0.04 microgram/kg/minute dopamine infusion, and abnormal prolactin response to a low-dose (0.004 microgram/kg/minute) dopamine infusion. Hence, persistent abnormalities in prolactin secretory dynamics were noted with more extensive testing in this patient when he was thought to have been cured. One year postoperatively, the hyperprolactinemia recurred, prolactin release was markedly resistant to dopamine, and an abnormal 24-hour prolactin profile of release was present. Thus, resistance of prolactin secretion to inhibition by dopamine was present in this patient with a prolactinoma. Additionally, an abnormal prolactin response to dopamine was noted to precede the development of hyperprolactinemia with tumor recurrence.

Adenoma↗
PubMed1985

Macroprolactinemia presenting like a pituitary tumor.

A serum prolactin level greater than 200 ng/ml is almost pathognomonic of a pituitary tumor in a nonpregnant woman. A patient with a three-year history of documented serum prolactin levels of 350 to 400 ng/ml and no evidence of a pituitary adenoma on computed axial tomographic scanning was recently studied. Detailed evaluation included a 24-hour prolactin profile that revealed blunting of the nocturnal augmentation of prolactin release, low-dose dopamine infusion resulting in normal inhibition of prolactin secretion, and a thyrotropin-releasing hormone bolus that showed a blunted stimulation of prolactin release. Analysis of circulating prolactin by column chromatography of her serum revealed that greater than 85 percent of her circulating immunoreactive prolactin had a molecular weight greater than 100,000 daltons (macroprolactin). This contrasts with other hyperprolactinemic states in which 85 percent of the serum prolactin elutes in a 22,000-dalton peak. Hence, macroprolactinemia is apparently a nonprogressive condition and a novel cause of massive hyperprolactinemia.

Adult↗