Biomedical subjects

Matthew Martin

Publications and source records attributed to Matthew Martin.

24 records · Page 2Linked to original sources

PubMed2004

Endoscopic diagnosis of a clinically silent aortoesophageal fistula: case report and review of the literature.

We report a rare case of a secondary aortoesophageal fistula discovered incidentally during elective upper endoscopy. The patient had previously undergone repair of a descending thoracic aortic aneurysm with a Dacron interposition graft. Esophagoscopy 2 months after the aneurysm repair demonstrated a large mid-esophageal erosion with visualization of the aortic graft at the base. The aortoesophageal fistula had been clinically silent to this point. During preparation for surgery the patient developed large-volume esophageal hemorrhage and died following attempted endovascular repair of the fistula. A review of the literature on the diagnosis and surgical management of aortoesophageal fistula is presented.

Aged↗

PubMed2004

Pedestrians injured by automobiles: relationship of age to injury type and severity.

BACKGROUND: There is little research on the effect of age on the nature and severity of injuries to pedestrians struck by automobiles. STUDY DESIGN: Trauma registry study included all auto versus pedestrian trauma admissions of pedestrians injured by automobiles at an academic Level I trauma center over 10 years and 4 months. Injury Severity Score, severe body area (head, chest, abdomen, extremities) trauma with Abbreviated Injury Score >3, specific organ injuries, and mortality were calculated according to age groups (< or =14 years, 15 to 55 years, 56 to 65 years, >65 years). RESULTS: During the study period 5,838 admissions were reviewed. There were 1,136 patients (19.4%) 14 years old or less, 3,741 (64.1%) who were 15 to 55 years, 420 (7.2%) 56 to 65 years, and 541 (9.3%) older than 65 years. Overall mortality was 7.7% and ranged from 3.2% in the age group 14 years or less to 25.1% in patients over 65 years. The incidences of severe trauma (Injury Severity Score >15) in the four age groups were 11.2%, 18.7%, 23.6%, and 36.8%, respectively. The incidences of critical trauma (Injury Severity Score >30) were 2.3%, 3.9%, 5.7%, and 13.9%, respectively. The incidence of severe head and chest trauma (Abbreviated Injury Score >3) increased with age. The incidence of solid organ and hollow viscus injuries was similar in all age groups. Spinal injuries increased significantly with age and ranged from 0.4% in the pediatric group to 8.5% in the elderly group. Pelvic and tibial fractures were significantly more common in adults; femur fractures were significantly more common in the pediatric group. CONCLUSIONS: Age plays an important role in the anatomic distribution and severity of injuries and survival outcomes after pedestrian injuries.

Abdominal Injuries↗

PubMed2003

Bone marrow-derived stem cells initiate pancreatic regeneration.

We show that transplantation of adult bone marrow-derived cells expressing c-kit reduces hyperglycemia in mice with streptozotocin-induced pancreatic damage. Although quantitative analysis of the pancreas revealed a low frequency of donor insulin-positive cells, these cells were not present at the onset of blood glucose reduction. Instead, the majority of transplanted cells were localized to ductal and islet structures, and their presence was accompanied by a proliferation of recipient pancreatic cells that resulted in insulin production. The capacity of transplanted bone marrow-derived stem cells to initiate endogenous pancreatic tissue regeneration represents a previously unrecognized means by which these cells can contribute to the restoration of organ function.

Animals↗

PubMed2003

Analysis of pesticide residues on museum objects repatriated to the Hupa tribe of California.

In the past, it was common practice for museum professionals and private collectors to apply a variety of pesticide agents to objects in their collections to preserve them from depredations by microorganisms, fungi, and other pests. The Native American Graves Repatriation and Protection Act allows federally recognized tribes to request that museums return objects taken from their ancestors. Given that poor records were kept on the treatment of individual objects, it is unknown whether specific objects are contaminated with these pesticide agents. Although chemical analysis represents the only reliable means to determine the types and levels of pesticides on these objects, surprisingly few publications document the extent of this contamination in museum collections. This paper reports on the determination of arsenic, mercury, and several organic pesticides on 17 objects that were recently repatriated to the Hupa tribe in northern California. Four samples were taken from each object: two for arsenic and mercury analysis via flame atomic absorption spectrophotometry and two for organic pesticide analysis via gas chromatography/mass spectrometry. Percent levels (wt/wt) of mercury were detected on many samples, and 0.001 to 0.183% (wt/wt) levels of p-dichlorobenzene, naphthalene, thymol, lindane, and/or DDT were detected on many of the samples. These results indicate that Hupa tribal members should not wear these objects in religious ceremonies, proper precautions should be followed when dealing with potentially contaminated objects, and that more serious consideration should be given to this issue at a national level.

Arsenic↗

PubMed2003

Wnt-5A augments repopulating capacity and primitive hematopoietic development of human blood stem cells in vivo.

Human hematopoietic stem cells are defined by their ability to repopulate multiple hematopoietic lineages in the bone marrow of transplanted recipients and therefore are functionally distinct from hematopoietic progenitors detected in vitro. Although factors capable of regulating progenitors are well established, in vivo regulators of hematopoietic repopulating function are unknown. By using a member of the vertebrate Wnt family, Wnt-5A, the proliferation and differentiation of progenitors cocultured on stromal cells transduced with Wnt-5A or treated with Wnt-5A conditioned medium (CM) was unaffected. However, i.p. injection of Wnt-5A CM into mice engrafted with human repopulating cells increased multilineage reconstitution by >3-fold compared with controls. Furthermore, in vivo treatment of human repopulating cells with Wnt-5A CM produced a greater proportion of phenotypically primitive hematopoietic progeny that could be isolated and shown to possess enhanced progenitor function independent of continued Wnt-5A treatment. Our study demonstrates that Wnt-5A augments primitive hematopoietic development in vivo and represents an in vivo regulator of hematopoietic stem cell function in the human. Based on these findings, we suggest a potential role for activation of Wnt signaling in managing patients exhibiting poor hematopoietic recovery shortly after stem cell transplantation.

Animals↗

PubMed2002

Gait initiation in community-dwelling adults with Parkinson disease: comparison with older and younger adults without the disease.

BACKGROUND AND PURPOSE: Initiation of gait requires transitions from relatively stationary positions to stability with movement and from double- to single-limb stances. These are deliberately destabilizing activities that may be difficult for people with early Parkinson disease (PD), even when they have no problems with level walking. We studied differences in postural stability during gait initiation between participants with early and middle stages of PD (characterized by Hoehn and Yahr as stages 1-3) and 2 other groups of participants without PD--older and younger adults. SUBJECTS: The mean ages of the 3 groups of participants were as follows: subjects with PD, 69.3 years (SD=5.7, range=59-78); older subjects without PD, 69.0 years (SD=3.9, range=65-79); and younger subjects without PD, 27.5 (SD=3.9, range=22-35). METHODS: A 3-dimensional motion analysis system was used with 2 force platforms to obtain data for center of mass (COM) and center of pressure (COP). The distance between the vertical projections of the COM and the COP (COM-COP distance) was used to reflect postural control during 5 events in gait initiation. RESULTS: By use of multivariate analysis of variance, differences in COM-COP distance were found among the 3 groups. An analysis of variance indicated differences for 4 of the 5 events in gait initiation. A Scheffe post hoc analysis demonstrated differences in gait initiation between the subjects with PD and both groups of subjects without PD (2 events) and between the subjects with PD and the younger subjects without PD (2 events). DISCUSSION AND CONCLUSION: The COM-COP distance relationship was used to measure postural control during the transition from quiet standing to steady-state gait. Differences between groups indicated that individuals with impaired postural control allow less COM-COP distance than do individuals with no known neurologic problems. The method used could prove useful in the development and assessment of interventions to improve ambulation safety and enhance the independence of people with impaired postural control.

Adult↗