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Biomedical subjects

M T Montgomery

Publications and source records attributed to M T Montgomery.

At least 19 recordsLinked to original sources
PubMed2005

Dissolved oxygen saturation controls PAH biodegradation in freshwater estuary sediments.

Polycyclic aromatic hydrocarbons (PAHs) are common contaminants in terrestrial and aquatic environments and can represent a significant constituent of the carbon pool in coastal sediments. We report here the results of an 18-month seasonal study of PAH biodegradation and heterotrophic bacterial production and their controlling biogeochemical factors from 186 sediment samples taken in a tidally influenced freshwater estuary. For each sampling event, measurements were averaged from 25-45 stations covering approximately 250 km(2). There was a clear relationship between bacterial production and ambient temperature, but none between production and bottom water dissolved oxygen (DO) % saturation or PAH concentrations. In contrast with other studies, we found no effect of temperature on the biodegradation of naphthalene, phenanthrene, or fluoranthene. PAH mineralization correlated with bottom water DO saturation above 70% (r(2) > 0.99). These results suggest that the proportional utilization of PAH carbon to natural organic carbon is as much as three orders of magnitude higher during cooler months, when water temperatures are lower and DO % saturation is higher. Infusion of cooler, well-oxygenated water to the water column overlying contaminated sediments during the summer months may stimulate PAH metabolism preferentially over non-PAH organic matter.

Bacteria↗
PubMed2000

Extraoral facial pain.

Craniofacial pain is a common chief complaint and is among the most frustrating diagnostic and treatment challenges encountered by emergency physicians. The efficient development of a differential diagnosis, the delivery of appropriate and effective therapies, and the appropriate referral of patients who present with craniofacial pain from extraoral sources are discussed. Disease descriptions, a diagnostic workup format, and acute management protocols are presented for the more common craniofacial pain entities.

Brain Neoplasms↗
PubMed1994

Induction of Chitin-Binding Proteins during the Specific Attachment of the Marine Bacterium Vibrio harveyi to Chitin.

Previous work has shown that attachment of Vibrio harveyi to chitin is specific and involves at least two chitin-binding peptides. However, the roles and regulation of these chitin-binding peptides in attachment are still unclear. Here we show that preincubation with the oligomeric sugars composing chitin stimulated chitinase activity, cellular attachment to chitin, and production of chitin-binding peptides. One of these peptides, a 53-kDa peptide, is produced constitutively and appears to mediate initial attachment to chitin. Synthesis of another peptide, a 150-kDa chitin-binding peptide, is induced by chitin and thus may be involved in time-dependent attachment. Coordinated regulation of attachment and degradation of chitin may give bacteria like V. harveyi a selective advantage over other bacteria in nutrient-poor aquatic environments.

Journal Article↗
PubMed1993

Role of Chitin-Binding Proteins in the Specific Attachment of the Marine Bacterium Vibrio harveyi to Chitin.

We examined the mechanism of attachment of the marine bacterium Vibrio harveyi to chitin. Wheat germ agglutinin and chitinase bind to chitin and competitively inhibited the attachment of V. harveyi to chitin, but not to cellulose. Bovine serum albumin and cellulase do not bind to chitin and had no effect on bacterial attachment to chitin. These data suggest that this bacterium recognizes specific attachment sites on the chitin particle. The level of attachment of a chitinase-overproducing mutant of V. harveyi to chitin was about twice as much as that of the uninduced wild type. Detergent-extracted cell membranes inhibited attachment and contained a 53-kDa peptide that was overproduced by the chitinase-overproducing mutant. Three peptides (40, 53, and 150 kDa) were recovered from chitin which had been exposed to membrane extracts. Polyclonal antibodies raised against extracellular chitinase cross-reacted with the 53- and 150-kDa chitin-binding peptides and inhibited attachment, probably by sterically hindering interactions between the chitin-binding peptides and chitin. The 53- and 150-kDa chitin-binding peptides did not have chitinase activity. These results suggest that chitin-binding peptides, especially the 53-kDa chitin-binding peptide and chitinase and perhaps the 150-kDa peptide, mediate the specific attachment of V. harveyi to chitin.

Journal Article↗
PubMed1993

The effects of severe bruxism on sleep architecture: a preliminary report.

Analysis of sleep in 5 severe bruxists revealed consistent sleep abnormalities. These abnormalities consisted of decreased REM latency (90%), decreased percentage of REM sleep (85%), and increased number of sleep stage transitions (75%). This sleep pattern suggests that bruxing can have a deleterious effect on sleep in otherwise healthy individuals. This effect on sleep can in the long run lead to difficulty in daytime functioning similar to the effects of sleep apnea or nocturnal myoclonus. These data also reveal a significant first night effect, hence future attempts at replicating and expanding these findings should take that into consideration. The small number of subjects studied, the lack of a standardized assessment of their daytime functioning, the lack of information regarding the degree of teethware and daytime bruxing activity limit the generalizability of our findings. A controlled study with a larger sample size can help further delineate the nature of such sleep changes as well as their impact on the patient's overall functioning.

Adult↗
PubMed1992

Morbidity and mortality from pharmacosedation and general anesthesia in the dental office.

Morbidity and mortality (M&M) statistics have been used to determine the safety of pharmacosedation and general anesthesia for dental procedures. Although relevant, these data often do not describe what actually caused the problems. Descriptive data are needed to understand etiologic factors and to accurately set malpractice insurance rates, establish legislative regulations, and determine means of prevention. The purpose of this study was to characterize the factors involved in causing M&M in a national data base of dental patients who received either pharmacosedation or general anesthesia. Letters were sent to all state dental boards requesting detailed information on cases associated with M&M during the last 15 years. Follow-up letters and telephone contacts were made with noncompliant boards. Forty-three cases were reported from nine states, with mortality comprising 81.4% of the cases. The mean patient age was 18 years, with a range from 2 to 42 years. Seventy-five percent of the cases were classified as American Society of Anesthesiologists (ASA) class I, 21% as ASA II, and 4% as ASA III. The mean number of pharmacological agents used was three, with a range from one to seven. In 32% of the cases heart rate was monitored, in 23% respiration was monitored, in 23% blood pressure was monitored, in 8% tissue oxygen saturation was monitored, and in 4% heart rhythm was monitored. Fifty-nine percent of the practitioners performed basic life support as a part of resuscitative efforts, 21% performed some measure of advanced cardiac life support, and in 45% of the cases narcotic reversal was attempted.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

The prevention and treatment of aspiration of vomitus during pharmacosedation and general anesthesia.

The aspiration of gastric contents can occur in patients with a depressed level of consciousness. Pulmonary aspiration is a serious potential complication of pharmacosedation and general anesthesia. Sequelae associated with aspiration include pulmonary obstruction, chemical pneumonitis, secondary infection, and possibly death. Morbidity following aspiration is enhanced with an increased volume of aspirate, a more acidic pH, a high particle content, and bacterial contamination. Treatment of aspiration is dependent on the nature of the aspirate. Identifying aspiration-susceptible patients, employing preventive measures, and using careful anesthetic technique can effectively reduce the risk of aspiration.

Anesthesia, General↗
PubMed1992

Changes in signs and symptoms following temporomandibular joint disc repositioning surgery.

Fifty-one subjects with documented intra-articular pathology refractory to non-surgical therapy underwent temporomandibular joint (TMJ) disc repositioning surgery. Following surgery, subjects were evaluated for 6 months to 6 years by clinical examinations and questionnaires at designated times, and by postsurgical joint imaging. Significant decreases were noted in pain (headache, TMJ pain, ear pain, and neck/shoulder pain), the incidence of joint sounds and locking, and the presence of dietary restrictions. However, 35% of the subjects continued to have residual TMJ pain, and a similar percentage continued to need periodic nonsteroidal anti-inflammatory drugs for analgesia. Some degree of dietary restriction remained in approximately 50% of the subjects, and joint sounds persisted in a similar percentage following surgery. Mean mouth opening was improved by 8 mm, although lateral movements were increased by less than 0.5 mm. Surgery did not decrease the occurrence of jaw deviation, and disc position was unchanged in 86% of the joints imaged at an average of 2 years following surgery. Although TMJ disc repositioning surgery significantly improved pain and dysfunction in TMJ surgery patients, the improvement in disc position was not maintained in most subjects following surgery.

Adolescent↗
PubMed1991

Success of temporomandibular joint arthroscopy in disk displacement with and without reduction.

Forty-three subjects with disk displacement without reduction (DNR) or disk displacement with reduction (DWR) underwent arthroscopic lysis and lavage of the temporomandibular joints. Both groups of subjects were assessed by clinical examination, a questionnaire, and joint imaging, to determine the impact of internal derangement type (DWR vs DNR) on postsurgical outcome. There were no significant differences in postsurgical outcomes between the two groups of meniscal disorders with respect to clinical and questionnaire data. However, the DNR group generally exhibited a smoother, less erratic recovery. After surgery dramatic improvements were in range of motion, pain, and function in both groups, although some level of residual pain and dietary limitation remained in approximately half the subjects. The incidence of joint sounds and deviation were not improved by surgery. Significant differences were found between the two groups with respect to imaging results. Arthroscopy had little effect on the disk positions of DNR subjects: 84% were unchanged after surgery, and the remaining 16% were improved. The disk position of DWR subjects appeared more labile, with 31% unchanged, 38% worsened, and 31% improved.

Adolescent↗
PubMed1991

Orofacial metastasis of pulmonary giant cell carcinoma.

A patient was admitted to the hospital with multiple skin nodules of recent origin and signs and symptoms suggestive of acute pulmonary infection. Because one of the skin masses was located overlying the left mandibular body region, the patient was referred to the hospital dentistry clinic for evaluation. Historical, clinical, and radiographic assessments were consistent with reactive lymphadenopathy, and an intraoral excisional biopsy was performed. The biopsy results were indicative of giant cell carcinoma, which was confirmed by biopsy results from a similar skin lesion on the shoulder and by malignant cells recovered in the sputum and pleural fluids. Although this carcinoma has been shown to rarely metastasize to the skin and lymphatics of the neck, this is the first case report of metastasis to facial lymphatics.

Adult↗
PubMed1990

The prevalence of cardiac valvular pathosis in patients with systemic lupus erythematosus.

The purpose of this study was to determine the prevalence of valvular pathosis in a population of patients with SLE, to assess the candidacy of such patients for antibiotic prophylaxis before dental treatment. The hospital records of 112 patients with SLE were reviewed and screened for endocarditis, heart murmurs, and other valvular pathosis. Two of the 112 patients had confirmed cases of bacterial endocarditis. This prevalence is comparable to endocarditis prevalence rates in patients with prosthetic valves and is also three times that in patients with rheumatic heart disease. The high prevalence of endocarditis in this population of patients with SLE suggests that according to present perspectives on patient management, patients with SLE should be considered for antibiotic prophylaxis before dental therapies associated with formation of a bacteremia.

Adolescent↗
PubMed1990

The use of glucocorticosteroids to lessen the inflammatory sequelae following third molar surgery.

Acceptance of the use of glucocorticosteroids in density to control postsurgical inflammation has been impaired by concerns over side effects, adrenal suppression, and efficacy. The pattern of administration generally used is characterized as short-term, high-dose or pulse therapy, which has not been associated with significant side effects or adrenal suppression beyond 10 days. The selection of an appropriate glucocorticosteroid with minimal mineralocorticoid activity and extended biological activity is desirable. Oral and parenteral dosing are possible, and the latter can be administered as acetates (repository) or esters. The efficacy of glucocorticosteroids in reducing pain, swelling, and trismus after third molar surgery is difficult to ascertain because of methodological inconsistencies between investigations. In general, studies that used low dosing schedules have failed to produce dramatic and prolonged results. High-dosing intravenous (IV) studies have demonstrated significant short-term improvements, but the effects were not sustained. Combining IV administration with multiple oral dosing or a single intramuscular (IM) dose may be required to extend short-term improvement. High-dosing IM studies have shown significant and sustained anti-inflammatory effects with a single dose administered either pre- or post-operatively.

Glucocorticoids↗
PubMed1989

Acyclovir prophylaxis for oral herpes simplex virus infection in patients with bone marrow transplants.

Reactivation of herpes simplex virus (HSV) appears to play a significant role in oral mucositis resulting from bone marrow transplantation. The acyclic guanosine derivative acyclovir has been shown to be effective in treating and protecting against HSV infection in this group. The purpose of this study was to determine the role of HSV reactivation in oral mucositis in patients undergoing bone marrow transplantation who were seronegative for HSV or who received acyclovir prophylaxis. The results suggest that HSV plays an insignificant role in oral mucositis in these patients.

Acyclovir↗
PubMed1989

Arthroscopic TMJ surgery: effects on signs, symptoms, and disc position.

Nineteen subjects with documented intra-articular pathology refractory to nonsurgical therapies underwent temporomandibular joint (TMJ) arthroscopy involving lysis and lavage in the superior joint space. Following surgery, subjects were evaluated for 6 to 12 months by clinical examinations and questionnaires at designated time periods and by postsurgical joint imaging. Significant improvement was noted in pain, mandibular movement, and diet. No improvement was noted in the incidence of joint sounds, and disc position was unchanged in 80% of the joints. The findings suggest that disc repositioning may not be needed to achieve clinical success.

Adult↗
PubMed1988

Intravascular angiomatosis (Masson's lesion).

Intravascular angiomatosis, also known as Massons' lesion, is a relatively uncommon, although important, tumor because it clinically mimics such benign lesions as mucocele, pyogenic granuloma, and hemangioma, as well as malignant neoplasms such as angiosarcoma and Kaposi's sarcoma. More important is the potential for misdiagnosis at the histological level that poses a significant problem to those unfamiliar with this lesion. This article reviews the literature on perioral intravascular angiomatosis and presents five additional cases.

Adult↗