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Biomedical subjects

M S Greenberg

Publications and source records attributed to M S Greenberg.

At least 19 recordsLinked to original sources
PubMed2002

Biological responses of Lumbriculus variegatus exposed to fluoranthene-spiked sediment.

Lumbriculus variegatus was used as a bioassay organism to examine the impact of the sediment-associated polycyclic aromatic hydrocarbon (PAH) fluoranthene on behavior, reproduction, and toxicokinetics. The number of worms increased between the beginning and end of the experiment at 59 microg x g(-1) fluoranthene, but at the next higher treatment (108 microg x g(-1)) the number of worms found was lower and not different from the control. Worms exposed to 95 microg x g(-1) also exhibited increased reproduction when fed a yeast-cerophyl-trout chow mixture. On a total biomass basis, only the 95 microg x g(-1) exposure with food exhibited a statistically significant increase over the nonfed control. Evaluation of reproduction at the two highest treatments was compromised by a brief aeration failure 2 days before the end of the experiment. The behavioral responses were followed as changes in biological burial rate (sediment reworking rate) of a 137Cs-labeled marker layer. The biological burial rate increased toward a plateau as the concentration increased from the control (3.9 microg x g(-1) dry weight total PAH) to 355 microg x g(-1) dry weight fluoranthene in sediment. The aeration failure had minimal impact on the determination of reworking rate because all the data for the rate determination were collected prior to the aeration failure. Uptake and elimination rates declined with increasing treatment concentration across the range of fluoranthene concentrations, 59-355 microg x g(-1) dry weight sediment. The disconnect between the increasing biological burial rates and the decreasing toxicokinetics rates with increasing exposure concentration demonstrates that the toxicokinetic processes are dominated by uptake and elimination to interstitial water. The bioaccumulation factor (concentration in the organisms on a wet weight basis divided by the concentration in sediment on a dry weight basis) ranged from 0.92 to 1.88 on day 10 and declined to a range of 0.52 to 0.99 on day 28 with the lowest value at the highest dose.

Animals↗
PubMed1999

Physiologically based pharmacokinetic modeling of inhaled trichloroethylene and its oxidative metabolites in B6C3F1 mice.

A physiologically based pharmacokinetic (PBPK) model for inhaled trichloroethylene (TCE) was developed for B6C3F1 mice. Submodels described four P450-mediated metabolites of TCE, which included chloral hydrate (CH), free and glucuronide-bound trichloroethanol (TCOH-f and TCOH-b), trichloroacetic acid (TCA), and dichloroacetic acid (DCA). Inhalation time course studies were carried out for calibration of the model by exposing mice to TCE vapor concentrations of either 100 or 600 ppm for 4 h. At several time points, mice were euthanized and blood, liver, kidney, lung, and fat were collected and analyzed for TCE and its oxidative metabolites. Peak blood TCE concentrations were 0.86 and 7.32 microgram/mL, respectively, in mice exposed to 100 and 600 ppm TCE. The model overpredicted the mixed venous blood and tissue concentrations of TCE for mice of both exposure groups. Fractional absorption of inhaled TCE was proposed to explain the discrepancy between the model predictions and the TCE blood time course data. When fractional absorption (53%) of inhaled TCE was incorporated into the model, a comprehensive description of the uptake, distribution, and clearance of TCE in the blood was obtained. Fractional uptake of inhaled TCE was further verified by collecting TCE in exhaled breath following a 4-h constant concentration exposure to TCE and validation was provided by testing the model against TCE blood concentrations from an independent data set. The submodels adequately simulated the distribution and clearance kinetics of CH and TCOH-f in blood and the lungs, TCOH-b in the blood, and TCA and DCA, which were respectively detected for up to 43 and 14 h postexposure in blood and livers of mice exposed to 600 ppm TCE. This is the first extensive tissue time course study of the major metabolites of TCE following an inhalation exposure to TCE and the PBPK model predictions were in good general agreement with the observed kinetics of the oxidative metabolites formed in mice exposed to TCE concentrations of 100 and 600 ppm.

Adipose Tissue↗
PubMed1999

A retrospective study of the management of oral mucous membrane pemphigoid with dapsone.

OBJECTIVE: The purpose of this retrospective study was to investigate the efficacy of dapsone therapy in the management of mucous membrane pemphigoid. STUDY DESIGN: The charts of 29 patients who had been diagnosed with mucous membrane pemphigoid by means of routine histologic analysis and direct immunofluorescence were reviewed. The oral features were graded according to severity of disease from 1 to 3. Each patient was assigned to one of 4 groups according to his or her response to therapy. RESULTS: Nine patients were treated successfully with topical corticosteroids alone. Eleven patients with moderate to severe disease who were treated initially with topical steroids showed minimal improvement; after dapsone was added, 7 of the 11 had total resolution of their lesions and 4 had greater than 75% improvement. Two patients had to discontinue dapsone because of side effects. CONCLUSIONS: In this group of 20 patients with moderate to severe mucous membrane pemphigoid, the use of dapsone in combination with topical corticosteroids caused greater than 75% resolution of oral lesions in all patients studied.

Administration, Topical↗
PubMed1998

Comprehensive health data systems spanning the public-private divide: the Massachusetts experience.

As systems of health care delivery have evolved from claims-based fee-for-service to capitated or managed care, with its emphasis on cost-effectiveness, quality, and performance measurement, some states have begun to experiment with new ways to collect, organize, and share health information. In many cases, the drivers of these changes have been purchasers of health care, including large and small private employers and public agencies such as Medicaid. One of the results of these changes is the increased interest in the sharing of health information, between health plans and employers, and, in some instances, between private plans and public agencies such as public health. Massachusetts, which has one of the highest rates of managed care penetration in the United States, has brought together the various parties involved in the collection and utilization of health information, to craft agreements on standards and protocols that will allow the sharing of health data. While much of the activity involves business transactions between private sector health plans, the Department of Medical Assistance (Medicaid) has joined with its private sector purchasing partners in demanding cost-effective, high-quality care; it is these demands that have helped stimulate the need to reorganize previously proprietary health information systems. The activities of two public-private coalitions, the Massachusetts Healthcare Purchaser Group and the Massachusetts Health Data Consortium, have been critical in initiating and supporting the complex processes that have led to significant changes in state-based systems of health information.

Health Maintenance Organizations↗
PubMed1998

When believing is seeing: the effect of scripts on eyewitness memory.

Two studies examined the conditions under which event schema or scripts produce gap-filling errors in eyewitness accounts of a robbery. In Study 1, scripts for the robbery of a convenience store were identified. Results revealed high agreement among the 120 participants concerning the sequence of actions for such a robbery. Based on the information obtained in Study 1, participants in Study 2 (N = 144) viewed one of two sequences of slides depicting a robbery of a convenience store by a lone robber. In one sequence, three central script actions were omitted and in the other, three peripheral script actions were omitted. In addition, rate of exposure was varied (2 vs. 8 sec) as was the length of the retention interval (5 min vs. 1 week). As predicted, there was a higher rate of false recognition for central as opposed to peripheral actions, and this tendency was exaggerated for the longer retention interval. The theoretical and practical implications of the findings are discussed.

Adult↗
PubMed1998

Intraoral contact allergy: a literature review and case reports.

Signs and symptoms of contact allergic reactions affecting the oral mucosa may mimic other common oral disorders, making diagnosis difficult. Patients frequently seek multiple consultations and do not receive the correct diagnosis or effective management. As intraoral contact allergy may be more prevalent than previously believed, a review of this topic is warranted. This article emphasizes signs and symptoms that suggest intraoral contact allergy, and the authors discuss the allergens that most frequently affect the oral mucosa.

Acrylic Resins↗
PubMed1997

Prevalence of hereditary hemochromatosis in a Massachusetts corporation: is Celtic origin a risk factor?

The prevalence of homozygous hereditary hemochromatosis (HHC) is estimated at 1:250 in Caucasian adults. Little is known about ethnic subpopulations that might be at increased risk for this disease. HLA data have suggested a Celtic origin for HHC. Screening for HHC was offered to all employees of the Massachusetts Polaroid Corporation. Participants with a transferrin saturation of >55% or >45% and an elevated serum ferritin concentration on two screenings were referred for liver biopsy. The diagnosis of HHC was based on histological criteria, quantitative hepatic iron determination, hepatic iron index, and the phlebotomy requirement for iron depletion. Participants completed a questionnaire regarding their ethnic background. Two thousand two hundred ninety-four employees were screened, and 5 cases of HHC were detected. All 5 cases involved Caucasian men, yielding a prevalence of 1:395 for the Caucasian population. Four of the 5 cases were of 100% British-Irish ancestry based on the country of origin of their grandparents. Additional analysis revealed that the majority of grandparents of all 4 individuals came from Ireland or Wales. The exact two-tailed trend test showed a significant association of HHC with Celtic background (P = .012). The estimated cost of screening per patient identified was $18,041. Polaroid Corporation has a high representation of employees of British-Irish ancestry. Our data suggest that they are at high risk for developing HHC. A significant association of HHC with Celtic ancestry was found in this subpopulation, supporting the concept of a Celtic origin for this disease.

Adult↗
PubMed1997

Relationship of cytomegalovirus to salivary gland dysfunction in HIV-infected patients.

In a previous retrospective study of HIV-infected patients we detected a relationship between xerostomia and the presence of cytomegalovirus in saliva. This prospective study compares 13 patients with HIV and a complaint of xerostomia and low salivary flow rates with a control group of 7 patients with HIV without xerostomia and normal salivary flow rates. Both groups were evaluated for the presence of cytomegalovirus in saliva, peripheral blood mononuclear cells, and labial minor salivary glands. Viral cultures, polymerase chain reaction, and histopathologic examination were used to detect cytomegalovirus. Xerostomia and low salivary flow rates were associated with the presence of CMV in saliva. The virus was detected in 10 of 13 xerostomia patients and 2 of 7 controls (p = 0.05, Fisher's exact test). Cytomegalovirus was detected in the saliva of patients who did not also have it in their blood suggesting a local source of virus replication such as the salivary glands. The minor salivary glands were not a major site of cytomegalovirus. Culture was more sensitive then polymerase chain reaction in detecting salivary cytomegalovirus as a result of the presence of inhibitors to the reaction in saliva. These results suggest a link between cytomegalovirus in saliva and salivary gland dysfunction in HIV-infected patients.

AIDS-Related Opportunistic Infections↗
PubMed1997

Toward standardization of health information.

NCVHS has made recommendations to the DHHS to standardize 42 core health data elements, a number of which relate to medical conditions and services. The committee has asked the DHHS Data Council to actively promote, both within the department and externally, standardization of data elements and definitions where substantial consensus already exists. For those elements that have been recognized as significant core data elements, but for which there is not consensus on approach or definition, the NCVHS is recommending that the Data Council support the formation of a public-private working group to conduct further study and evaluation. This group, or a separate group, could also be the focus for evaluating additions to the list of core data elements and for setting up methods for testing and promulgating the final products. The coming 12-18 months will be exceedingly important for health data standardization efforts in the US as the DHHS responds to both the NCVHS recommendations and the legislation recently enacted by Congress.

Abstracting and Indexing↗
PubMed1996

(1S,2R)-D-erythro-2-(N-myristoylamino)-1-phenyl-1-propanol as an inhibitor of ceramidase.

In this study, we have examined the cellular and biochemical activities of the ceramide analog (1S,2R)-D-erythro-2-(N-myristoylamino)-1-phenyl-1-propanol (D-erythro-MAPP). Addition of 5 microM D-e-MAPP to HL-60 human promyelocytic leukemia cells resulted in a concentration- and time-dependent growth suppression accompanied by an arrest in the G0/G1 phase of the cell cycle; thus mimicking the action of exogenous ceramides. Its enantiomer L-e-MAPP was without effect. Two lines of evidence suggested that D-e-MAPP may not function as a direct analog of ceramide. First, D-e-MAPP possesses a stereochemical configuration opposite to that of D-erythro-ceramide. Second, D-e-MAPP failed to activate ceramide-activated protein phosphatase in vitro. Therefore, we examined if D-e-MAPP functioned indirectly by modulating endogenous ceramide levels. The addition of D-e-MAPP to cells, but not L-e-MAPP, caused a time- and concentration-dependent elevation in endogenous ceramide levels reaching greater than 3-fold over baseline following 24 h of treatment. Both D-e-MAPP and L-e-MAPP underwent similar uptake by HL-60 cells. D-e-MAPP was poorly metabolized, and remained intact in cells, whereas L-e-MAPP underwent a time- and concentration-dependent metabolism; primarily through N-deacylation. In vitro, L-e-MAPP was metabolized by alkaline ceremidase to an extent similar to that seen with C16-ceramide. D-e-MAPP was not metabolized. Instead, D-e-MAPP inhibited alkaline ceramidase activity in vitro with an IC50 of 1-5 microM. D-e-MAPP did not modulate the activity of other ceramide metabolizing enzymes in vitro or in cells, and it was a poor inhibitor of acid ceramidase (IC50>500 microM). Finally, D-e-MAPP inhibited the metabolism of L-e-MAPP in cells. These studies demonstrate that D-e-MAPP functions as an inhibitor of alkaline ceramidase in vitro and in cells resulting in elevation in endogenous levels of ceramide with the consequent biologic effects of growth suppression and cell cycle arrest. These studies point to an important role for ceramidases in the regulation of endogenous levels of ceramide.

Acid Ceramidase↗
PubMed1996

HIV-associated lesions.

Oral lesions are common in HIV infection and may be the first sign of AIDS. This article reviews the oral fungal and viral infections commonly detected in HIV-infected patients, particularly candidiasis, deep fungal infections, herpes simplex virus infections, cytomegalovirus infections, and oral hairy leukoplakia. The neoplasms associated with AIDS such as oral Kaposi's sarcoma and lymphoma are related periodontal diseases. Each disorder is discussed by clinical appearance, diagnosis, and management. Recent advances in therapy are stressed.

AIDS-Related Opportunistic Infections↗
PubMed1996

Herpesvirus infections.

There are presently seven known herpes viruses that infect humans. Those viruses are important in the fields of oral medicine and dentistry because they cause oral lesions, infect saliva, and cause serious and potentially life-threatening infections in patients whose immune systems are compromised by cancer chemotherapy, immunosuppressive drugs, or HIV infection. This article reviews the basic virology and clinical manifestations of the herpes viruses while highlighting the clinical aspects of herpes-related diseases important to dentistry.

Chickenpox↗
PubMed1995

Relationship of oral disease to the presence of cytomegalovirus DNA in the saliva of AIDS patients.

Cytomegalovirus is an important pathogen in persons infected with human immunodeficiency virus. In this study a thorough oral examination was done and blood and urine cultures for cytomegalovirus were obtained from a group of 31 patients with acquired immunodeficiency syndrome with CD4 lymphocyte counts less than 150 cells/mm3. Whole saliva was also collected for detection of cytomegalovirus deoxyribonucleic acid (DNA) via the polymerase chain reaction. The presence of cytomegalovirus DNA in the saliva specimens was not related to the presence of cytomegalovirus in the urine, which suggests a local source of cytomegalovirus from salivary gland and kidney parenchyma. There was also a strong statistical relationship between salivary cytomegalovirus DNA and xerostomia (p = 0.0004), which suggests that cytomegalovirus may be a cause of salivary gland dysfunction in patients with acquired immunodeficiency syndrome with low CD4 counts.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Evidence for construct validity of the TMJ scale in a sample of chronic post-traumatic headache patients.

The construct validity of the TMJ Scale was examined in a sample of chronic post-traumatic headache patients. Clinical indicators of temporomandibular (TM) dysfunction and measures of psychosocial distress were compared with relevant scales of the TMJ Scale. The clinical indicators were first subjected to principal components analysis. The resulting factor scores correlated significantly with selected physical domain scales of the TMJ Scale. The factor scores also significantly predicted the TMJ Global Scale in a regression analysis. Selected psychosocial domain scales of the TMJ Scale correlated strongly with measures of depression and anger and a clinical diagnosis of post-traumatic stress disorder. The results support the validity of the TMJ Scale and demonstrates its utility with post-traumatic headache patients.

Accidents, Traffic↗