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Biomedical subjects

D M Cummings

Publications and source records attributed to D M Cummings.

At least 19 recordsLinked to original sources
PubMed2006

Racial disparity in treatment of osteoporosis after diagnosis.

INTRODUCTION: Racial disparities have been identified in a number of areas in clinical medicine. Patients diagnosed with osteoporosis should be treated similarly regardless of race. However, limited data are available on the relative frequency of treatment by race after diagnosis of osteoporosis. METHODS: We analyzed all 739 dual-energy X-ray absorptiometry (DXA) results obtained of women 50 years old and older between 1998 and 2002 at our medical center. Our study sample was 82% Caucasian and 15% African American. Of 353 women who had low bone mineral density on first DXA, we abstracted the electronic and paper medical records to compare treatment rates by race. RESULTS: Of the women diagnosed with osteoporosis or osteopenia, 80.0% and 68.3%, respectively, were started on antiresorptive medications. Of the African American women, 61.9% diagnosed with osteoporosis were started on antiresorptive treatment compared with 83.3% of Caucasian women (p<0.05). African American women with low bone mass were less likely than Caucasian women to be smokers (p<0.05) and use alcohol (p<0.01) but were more likely to be on corticosteroids (p<0.05). No other significant differences were found among treated and nontreated groups that might explain the disparity in treatment. CONCLUSION: A smaller proportion of African American than Caucasian women with osteoporosis received antiresorptive medications after a DXA diagnosis. This significant disparity requires further study in a larger population.

Absorptiometry, Photon↗
PubMed2001

Screening for diabetic retinopathy in rural areas: the potential of telemedicine.

Diabetic retinopathy is a common cause of blindness, and screening can identify the disease at an earlier, more treatable stage. However, rural individuals with diabetes may have limited access to needed eye care. The objective of this project was to demonstrate the feasibility of a diabetic retinopathy screening program using a state-of-the-art nonmydriatic digital fundus imaging system. The study involved a series of patients screened in primary care and public health locations throughout seven predominantly rural counties in eastern North Carolina. Images of each fundus were obtained and sent to a retinal specialist. The retinal specialist reviewed each image, recorded image quality, diagnosed eye disease and made recommendations for subsequent care. Of 193 volunteers with a history of diabetes mellitus, 96.3 percent reported that they were very comfortable or comfortable with the camera. Eighty-five percent of images were rated as good or fair by the retinal specialist. The retinal specialist also reported being very certain or certain of the diagnosis in 84 percent of cases. Image quality correlated highly with the certainty of diagnosis (Spearman's rank order correlation coefficient = 0.79; P < 0.001). The average time since the previous examination by an eye care specialist for diabetic subjects was two years. Approximately 62 percent of diabetic patients had diagnosable eye conditions, the most common of which was diabetic retinopathy (40.9 percent). In this convenience sample, African Americans, despite similar age and disease duration, were more likely to have retinopathy. Digital imaging is a feasible screening modality in rural areas, may improve access to eye care, and may improve compliance with care guidelines for individuals with diabetes mellitus.

Adult↗
PubMed2000

Pattern of olfactory bulb innervation returns after recovery from reversible peripheral deafferentation.

The olfactory epithelium (OE) is unusual in its ability to regenerate and reinnervate its target, the olfactory bulb (OB), after deafferentation. To address the question of whether olfactory receptor neuron (ORN) axons preserve their topographic organization when they reestablish synaptic contact with the OB, the authors examined the pattern of ORN axon reinnervation into the bulb of adult H-OMP-lacZ-6 transgenic mice during and after recovery from chemical deafferentation. In the H-OMP-lacZ-6 mouse strain, lacZ expression is limited to a subset of ORNs that are distributed bilaterally in the OE and project primarily to a few glomeruli in the ventromedial region of the OB. The OE was lesioned by intranasal irrigation with Triton X-100, and the distribution of 5-bromo-4-chloro-3-indolyl-beta-D-galactopyranoside (X-gal)-stained cells was examined in the OE along with beta-galactosidase-immunoreactive (beta-gal-ir) axonal processes in the OB after short (1 week), intermediate (3 week), and long (6-7 weeks) recovery times. One week after the lesion, immunostaining for beta-gal and olfactory marker protein was virtually eliminated in the bulb. After 3 weeks of recovery, beta-gal-containing axons appeared to target many of the same locations innervated in bulbs of unlesioned mice. The region that received the highest density of axonal innervation in controls, however, contained only a few processes at that time. After 6-7 week recovery periods, the pattern of X-gal staining in the OE and beta-gal-ir axons in the OB closely resembled that of unlesioned mice. These results demonstrate that the topographic distribution of ORNs in the OE and the pattern of axon innervation in the OB can be reconstituted after chemical deafferentation.

Animals↗
PubMed2000

Changing practices in the use of pneumococcal vaccine.

BACKGROUND AND OBJECTIVES: An important issue facing primary care practices is how to best improve preventive services to patients. We sought to determine if an intervention designed by a continuous quality improvement (CQI) process (reminder sticker and patient education sign in each examining room) or a patient education intervention (sign only) could increase the rate of pneumococcal vaccination. METHODS: These two interventions were administered over a 6-month period in a controlled, prospective study design in a family practice residency program clinic. The study targeted patients ages 65 and older and patients ages 2-64 with diabetes mellitus who had never received the pneumococcal vaccine. The main outcome measure was the vaccination rate in the targeted population. RESULTS: A total of 1,647 patient encounters involving 778 patients were documented during the study period. Overall, the reminder and sign module had higher percentages of pneumococcal vaccination in this target population (20% versus 11% for sign only, versus 7% control). Chi-square analysis revealed a statistically significant difference for this group, compared with placebo, but not for the sign-only group. CONCLUSIONS: An intervention designed from a CQI process to impact the office patterns of primary care physicians can produce measurable changes in pneumococcal vaccination rates.

Adolescent↗
PubMed1999

Targeted deletion of a cyclic nucleotide-gated channel subunit (OCNC1): biochemical and morphological consequences in adult mice.

The olfactory cyclic nucleotide-gated channel subunit 1 (OCNC1) is required for signal transduction in olfactory receptor cells. To further investigate the role of this channel in the olfactory system, the biochemical and morphological consequences of targeted disruption of OCNC1 were investigated in adult mice. Null as compared to wild-type mice had smaller olfactory bulbs, suggesting compromised development of the central target of the receptor cells. Ectopic olfactory marker protein (OMP)-stained fibers localized to the external plexiform layer reflected the relative immaturity of the olfactory bulb in the null mice. The olfactory epithelium of the knock-out mouse was thinner and showed lower expression of olfactory marker protein and growth-associated protein 43, indicating decreases in both generation and maturation of receptor cells. Tyrosine hydroxylase (TH) expression in the olfactory bulb, examined as a reflection of afferent activity, was reduced in the majority of periglomerular neurons but retained in atypical or "necklace" glomeruli localized to posterior aspects of the olfactory bulb. Double label studies demonstrated that the remaining TH-immunostained neurons received their innervation from a subset of receptor cells previously shown to express a phosphodiesterase that differs from that found in most receptor cells. These data indicate that expression of OCNC1 is required for normal development of the olfactory epithelium and olfactory bulb. The robust expression of TH in some periglomerular cells in the OCNC1-null mice suggests that receptor cells innervating these glomeruli may use an alternate signal transduction pathway.

Animals↗
PubMed1998

Oral poisonings: guidelines for initial evaluation and treatment.

The initial evaluation and management of poisoned patients should be comprehensive and include an accurate history whenever possible, stabilization of the patient's condition, a physical assessment to evaluate the extent of poisoning and the presence of concurrent conditions, decontamination of the gastrointestinal tract using activated charcoal, gastric lavage, administration of ipecac or irrigation, poison-specific treatment with administration of antidotes when indicated and proper disposition. Consultation with a poison control center is often helpful in assessing and treating these patients.

Administration, Oral↗
PubMed1998

Lipid and lipoprotein responses to oral combined hormone replacement therapy in normolipemic obese women with controlled type 2 diabetes mellitus.

This study investigated the effects of oral combined hormone replacement therapy (OCHRT) on lipid concentrations and subpopulation distribution of lipoproteins in nine postmenopausal women with type 2 diabetes mellitus and moderate glycemic control. After 16 weeks of continuous daily therapy of conjugated estrogens 0.625 mg and medroxyprogesterone 2.5 mg, the mean concentration of high-density lipoprotein (HDL) cholesterol showed a statistically significant increase of 16.7%, predominantly in the HDL2 subfraction. No statistically significant changes in mean concentrations of total cholesterol, low-density lipoprotein (LDL) cholesterol, triglycerides, very low-density lipoprotein (VLDL) triglycerides, apolipoprotein A1, or apolipoprotein B were evident. Likewise, no changes were found in the average diameter of VLDL, LDL, or HDL particles; triglyceride concentrations of VLDL subfractions; cholesterol concentrations of LDL subfractions; or chemical composition of plasma LDL. These findings lend further support to the use of OCHRT in postmenopausal women with diabetes to decrease their risk for coronary artery disease.

Administration, Oral↗
PubMed1997

Olfactory bulb recovery after early sensory deprivation.

Olfactory bulbs retain the ability to acquire new neurons throughout life. Unilateral olfactory deprivation during the first postnatal month in rats results in a dramatic reduction in the size of the experimental olfactory bulb. Part of this reduction is attributable to the death of neurons and glia. To examine the regenerative capacity of the juvenile olfactory bulb, we developed a technique for reversible olfactory deprivation. Reversible blockade from postnatal day 1 (P1) to P20 or P30 results in reduced bulb volume and tyrosine hydroxylase immunostaining, and decreased depth in the olfactory mucosa. In another experiment, normal stimulation was restored for varying periods of time, and experimental and control bulb volumes were measured. Recovery of bulb size occurs after 40 d of normal stimulation. Rats injected with a thymidine analog to label dividing cells during the recovery period revealed that rescue results at least in part from the addition of new neurons and glia. Thus, cells born after the return of normal levels of environmental stimulation can replace some of the neurons and glia that are lost during olfactory deprivation. This system can be used to study mechanisms that underlie neuronal regeneration in the maturing mammalian brain.

Animals↗
PubMed1997

Effects of unilateral olfactory deprivation in the developing opossum, Monodelphis domestica.

Unilateral naris closure in young rodents leads to striking alterations in the development of the ipsilateral olfactory system. One of the most pronounced effects is a 25% reduction in the size of the experimental olfactory bulb, a change that stems in part from decreased cell survival. Since naris occlusion in rodents alters the system more during development than in adulthood, we investigated the consequences of olfactory deprivation in a species that is born in a very immature state, Monodelphis domestica. In this pouchless marsupial, offspring are born after a short 14-day gestation. In the present study, the thymidine analogue bromodeoxyuridine was used to examine early postnatal neurogenesis in the olfactory bulb. Unlike rats and mice, neurogenesis of the main output neurons (the mitral cells) continues into postnatal life. Unilateral naris closure was begun on postnatal day 4 (P4) or P5 in Monodelphis and continued for 30 or 60 days. Laminar volume measurements revealed a significant reduction in the size of the experimental bulb following 60, but not 30, days of early olfactory deprivation. Mitral cell number estimates indicated a significant reduction after both 30 and 60 days of naris closure. The immaturity of Monodelphis offspring may render the population of mitral cells susceptible to the effects of olfactory deprivation. These findings suggest that afferent activity plays a role in the survival of all bulb neurons, irrespective of cell class.

Animals↗
PubMed1997

The effects of variable periods of functional deprivation on olfactory bulb development in rats.

Dramatic alterations occur in the developing olfactory bulb when air flow is reduced through one-half of the nasal cavity. Naris closure on the day after the day of birth (P1) in rats, for example, results in reduced cell survival in the ipsilateral bulb by P20 and a substantial (25%) decrease in bulb size by P30. Almost immediate changes in protein synthesis and cell metabolism are also observed, and one prevalent theory suggests that these changes may be important in specifying which cells are subsequently eliminated. In the present study we used a reversible technique for unilateral naris closure to examine the sensitive period for the effects of olfactory deprivation on bulb size and cell survival. This technique involves the insertion of removable plugs into a rat pup's external naris. We occluded the naris for increasing periods of time (P1-P10, P1-P15, or P1-P20), reared all animals to P30, and measured volumes of bulb laminae. In addition, we examined the duration of naris closure needed to affect cell survival by injecting animals with the thymidine analogue bromodeoxyuridine to label cells born soon after the onset of olfactory deprivation. Results indicate that relatively long periods of naris occlusion (P1-P15 or longer) are required to produce a substantial reduction in experimental bulb size. Cell survival was decreased following olfactory deprivation from P1 to P10, but not after deprivation from P1 to P3. These data support the hypothesis that changes that occur within 48 h of naris closure are not sufficient to affect cell survival.

Animals↗
PubMed1997

NSAIDs revisited: selection, monitoring, and safe use.

Although nonsteroidal anti-inflammatory drugs (NSAIDs) are effective analgesic and anti-inflammatory agents, they may have adverse effects on the gastrointestinal, hepatic, renal, pulmonary, and platelet aggregation systems in susceptible patients. Careful consideration of the risks and benefits, judicious dosing, and careful monitoring by the primary care physician are therefore essential. The authors of this article review both the therapeutic and adverse effects of NSAIDs and provide suggestions for safe clinical use.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1997

Development of the anterior commissure in the opossum: midline extracellular space and glia coincide with early axon decussation.

While the anterior commissure has been shown to be an important route of information transfer in the forebrain, relatively little is known about its anatomical development. Glial substrates and extracellular spaces have been associated with the maturation of other large-fiber tracts, such as the corpus callosum and retinofugal pathway. The present study examined early stages in the maturation of the commissure in the gray short-tailed opossum, Monodelphis domestica. Monodelphis offspring are born after a short 14-day gestation, and, unlike in rats and mice, the anterior commissure develops entirely during the postnatal period. A number of techniques were employed: the carbocyanine dye Dil was used to label early axons in the region, semithin plastic sections were used to examine the extracellular environment of the developing commissure, and immunocytochemistry for glial fibrillary acidic protein (GFAP) was used to characterize glial components. Results suggest that the first commissural fibers that cross the midline pass through a region of large extracellular spaces and may use GFAP-immunoreactive cells and processes as guides during their midline decussation.

Animals↗
PubMed1995

Migrating luteinizing hormone-releasing hormone (LHRH) neurons and processes are associated with a substrate that expresses S100.

Luteinizing hormone-releasing hormone (LHRH) containing neurons arise in the region of the medial olfactory placode and migrate into the developing olfactory bulbs and basal forebrain along branches of the terminal and vomeronasal nerves. The neurons ultimately come to reside in olfactory and septo-preoptic areas and project extensively to several brain regions, including the preoptic area and median eminence. The present study examined the expression of a glial-associated guidance molecule, S100, as a possible substrate for this migration. Monodelphis domestica (the Brazilian grey, short-tailed opossum) was studied since this species gives birth to very immature, young, allowing access to early periods of mammalian forebrain development. Immunoreactivity for both S100 and LHRH-containing neurons and fibers were observed to be closely associated along the entire LHRH migratory route from the vomeronasal organ to the septo-preoptic areas as early as the day of birth (PO). By P10, S100-immunoreactivity was also seen in areas containing LHRH-immunoreactive fibers such as the preoptic area and median eminence. We suggest that S100, a protein with neurotrophic properties in vitro, acts as a guidance molecule for migrating LHRH-immunoreactive neurons and elongating processes.

Animals↗
PubMed1994

Effect of oral magnesium supplementation on selected cardiovascular risk factors in non-insulin-dependent diabetics.

OBJECTIVE: To evaluate the impact of oral magnesium supplementation on risk factors for end-organ disease in patients with non-insulin-dependent diabetes mellitus (NIDDM). DESIGN: A 16-week randomized, double-blind, placebo-controlled crossover trial. SETTING: Outpatient center of an academic family medicine residency program. PATIENTS: Twenty-eight patients (age range, 28 to 84 years; 57.1% black; 85.7% women) with NIDDM controlled by diet and/or an oral hypoglycemic, with a serum cholesterol levels over 5.20 mmol/L (200 mg/dL). INTERVENTION: Following a 2-week placebo run-in period, each patient was randomized to receive either sustained-release magnesium chloride (Slo-Mag), 384 mg/d, or an identical-appearing placebo for 6 weeks. After a 2-week interim washout period, each patient was then treated with the alternative regimen for an additional 6-week period. MAIN OUTCOME MEASURES: The systolic and diastolic blood pressure and levels of serum glucose, low-density and high-density lipoprotein and total cholesterol, triglycerides, and serum and total erythrocyte magnesium were measured at the beginning, midpoint, and end of each 6-week treatment phase. RESULTS: Systolic blood pressure fell an average of 7.4 mm Hg (P < .05) with treatment. There was no significant change in diastolic blood pressure or levels of serum glucose, low-density and high-density lipoprotein and total cholesterol, triglycerides, or serum and erythrocyte magnesium. CONCLUSIONS: Oral magnesium supplementation in the doses and duration studied is modestly effective in reducing systolic blood pressure in patients with NIDDM but has little impact on other important biochemical parameters related to diabetes-associated end-organ disease.

Administration, Oral↗
PubMed1994

Changes in cell proliferation in the developing olfactory epithelium following neonatal unilateral naris occlusion.

Surgical closure of an external naris reduces airflow through one side of the nasal cavity. Previous studies using [3H]thymidine autoradiography have demonstrated that rats subjected to the procedure on Postnatal Day 1 (P1) exhibit reduced cellular proliferation in the olfactory mucosa by P30. We investigated cell production at earlier ages to determine (a) when the effect first emerges, and (b) whether septal, dorsal, and lateral regions of the nasal cavity responded similarly. Both short (2-h) and long (30-day) survival groups were tested. Results from the first group indicate that changes in proliferation emerge between P10 and P20, and that the septum is more affected than other regions of the nasal cavity. No differences were observed in the long survival groups, perhaps due to changes in patterns of cell production or death.

Airway Obstruction↗
PubMed1994

A review of selected newer nonsteroidal anti-inflammatory drugs.

Development of nonsteroidal anti-inflammatory drugs (NSAIDs) with a goal of improved efficacy and lower toxicity has continued, resulting in the introduction of etodolac, ketorolac, nabumetone and oxaprozin on the market. Each of these agents appears to be as effective as other commonly used NSAIDs in the treatment of rheumatoid arthritis or osteoarthritis. Studies of nabumetone and etodolac show a lower incidence of serious gastrointestinal toxicity with both drugs, but additional large clinical trials are necessary to confirm these findings. Although ketorolac, which is now available in oral form, is an effective analgesic, its long-term use is limited by a high incidence of gastrointestinal toxicity. Oxaprozin is an effective, long-acting anti-inflammatory analgesic, but its comparative advantages remain undefined.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1993

Influence of digoxin immune Fab therapy and renal dysfunction on the disposition of total and free digoxin.

OBJECTIVE: To characterize the disposition of total and free serum digoxin following the administration of digoxin Fab antibody in patients with varying degrees of renal function. DESIGN: Observational study of pharmacokinetics and pharmacodynamics. SETTING: Critical care and telemetry units of two university-affiliated teaching institutions, Hartford Hospital and Henry Ford Hospital. PATIENTS: Fourteen digoxin-intoxicated patients (baseline total digoxin > 3.2 nmol/mL) with mean (+/- SD) serum creatinine of 380.1 +/- 212.2 mumol/L who received digoxin Fab antibody therapy. MEASUREMENTS: Serum was drawn every 12 to 24 hours for 80 to 327 hours after Fab administration. Total and free digoxin were assayed in serum by fluorescence polarization immunoassay or modified immunofluorometric assay. RESULTS: Before Fab was administered, total digoxin ranged from 3.5 to 10.5 nmol/mL. After treatment with Fab, total digoxin increased rapidly to a mean (+/- SD) maximum of 51.8 +/- 22.7 nmol/mL and decreased to 7.2 +/- 4.7 nmol/mL at the last measurement. Total digoxin was eliminated in a two-phase fashion. The half-life of the initial phase of total digoxin decline was 11.6 +/- 4.1 hours, and the half-life of the second or terminal elimination phase was 118 +/- 57 hours. Free digoxin levels decreased rapidly following Fab therapy, to a mean nadir of 0.6 +/- 1.1 nmol/mL, but rebounded to a mean maximum free digoxin concentration of 1.7 +/- 1.3 nmol/mL in 77 +/- 46 hours. The time to maximum free digoxin rebound occurred later in patients with end-stage renal disease (n = 4) compared with other patients (127 +/- 40 hours compared with 55 +/- 28 hours). CONCLUSION: Elimination of digoxin following Fab therapy is prolonged in digoxin-toxic patients with renal dysfunction. In addition, rebound of free digoxin is delayed in anephric patients. Monitoring free digoxin following the administration of Fab may be of value in selected patients to guide additional Fab dosing, confirm possible rebound toxicity, or guide the reinitiation of digoxin therapy.

Adult↗