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Biomedical subjects

M Finnegan

Publications and source records attributed to M Finnegan.

At least 19 recordsLinked to original sources
PubMed2001

Oblique sagittal view of the anterior cruciate ligament: comparison of coronal vs. axial planes as localizing sequences.

The purpose of this study was to determine whether oblique sagittal T2-weighted images of the anterior cruciate ligament (ACL) are better prescribed off axial or coronal localizing images. Thirty-one patients underwent two sets of oblique sagittal T2-weighted fast spin-echo sequences to evaluate the ACL. One oblique was prescribed from a coronal localizing sequence, while the other was prescribed off an axial series. Objective (average number of images to demonstrate ACL) and subjective (radiologist's confidence level) evaluations of both sequences were performed independently of the other and then comparatively by two radiologists. The coronally prescribed sagittal oblique was subjectively preferred in 18 patients, the axially prescribed oblique was preferred in one patient, and both sequences were felt to be equivalent in 12 patients. In 13 intact ligaments, the average number of images clearly demonstrating the entire length of the ACL was 1.77 on the coronally prescribed sequence and 1.31 on the axially prescribed images. Oblique sagittal images prescribed off a coronal localizer are both subjectively and objectively more effective than axially prescribed sagittal obliques in evaluating the ACL.

Adolescent↗
PubMed2000

T. Dale Stewart: remembrances of a scholar and colleague.

T. Dale Stewart's contributions had a considerable influence on the development and early evolution of the field of forensic anthropology. This composition provides a perception of Stewart from the viewpoint of an advanced graduate student and then a young colleague. It explains, in part, the quiet leadership and assistance that Stewart provided at various professional and familiar levels to one individual and is indicative of the broad effect that Stewart had on generations of students and professionals in anthropology, osteology and forensic anthropology.

Forensic Anthropology↗
PubMed1999

Effect of smoking on tibial shaft fracture healing.

Of 146 consecutive closed and Grade I open tibia shaft fractures treated with cast immobilization, external fixation, or intramedullary rod fixation during a 4-year period, 44 of 76 (58%) tibias of patients who smoked and 59 of 70 (84%) tibias of patients who did not smoke had followup to union or followup beyond 1 year. The demographics, fracture patterns, and treatments of the two groups were similar. Two of the 44 patients who smoked had nonunions at the 1-year followup, whereas none of the patients who did not smoke had nonunions. Of the 103 tibias with complete followup to union, the median time to clinical healing for patients who smoked (269 days) was significantly greater than that of patients who did not smoke (136 days). Likewise, there was a 69% delay in radiographic union in the group that smoked as interpreted by a radiologist blinded to the two groups. Statistical differences in clinical and radiographic healing rates between those who smoked and those who did not smoke were observed for patients receiving intramedullary fixation or external fixation. Statistical differences were not seen in the clinical and radiographic healing of tibias treated with cast immobilization, although tibias of patients who smoked took 62% longer to heal. The current data suggest that tibias of patients who smoke who require treatment with intramedullary nailing or external fixation require more time to heal than do those of patients who do not smoke.

Adult↗
PubMed1999

Three-dimensional collagen gel culture promotes osteoblastic phenotype in bone marrow derived cells.

When calvarial cells or osteogenic cell lines were cultured in type I collagen gel, calcification was observed early and diffusely compared to monolayer culture. Bone marrow derived cells were cultured in three-dimensional type I collagen gel to investigate whether the cells can differentiate into osteogenic cells. In terms of efficient induction of osteogenic differentiation, we compared collagen gel culture to type I collagen coated dish culture and collagen-free plastic dish culture by morphology, alkaline phosphatase activity, and mRNA expression for type I collagen and osteopontin. Bone marrow derived primary cells formed colonies consisting of fibroblastic cells positively expressing alkaline phosphatase activity. Mineral deposition was observed in both primary and the 3rd passaged cells cultured in collagen gel, whereas the 3rd passaged cells on plastic dishes failed to be mineralized. Cells in collagen gel showed higher alkaline phosphatase activity than those in the other two methods suggesting that three-dimensional collagen network stimulated osteoblastic differentiation effectively. The expression level for type I collagen mRNA of the cells in collagen gel was three times higher in the 3rd passaged cells, and was slightly decreased in primary cells compared to the other two methods. The osteopontin mRNA expression of the cells in collagen gel was four times higher in the 3rd passaged cell culture but lower in primary cell cultures. These results suggested that collagen gel culture might be a useful environment for osteogenic induction of passaged cells derived from bone marrow.

Alkaline Phosphatase↗
PubMed1996

The effect of chronic hypertension on skin blood flow.

OBJECTIVE: To determine whether the cutaneous microvasculature of the spontaneously hypertensive rat (SHR) is affected by chronic hypertension. DESIGN: We used laser Doppler techniques to measure skin blood flow in 22 SHR and in 22 non-hypertensive Wistar-Kyoto (WKY) rats over a 1-year time span, beginning at age 3 months. Sites of measurement included the back, leg, and root of the tail, areas with a predominantly nutritive perfusion, and the plantar surface of the paw, which has a large contribution from large arterioles and venules. Flow was measured at basal skin temperature and at the maximally heat-stimulated condition of 44 degrees C. Systolic tail arterial blood pressures were measured concurrently. RESULTS: At baseline, systolic blood pressures were considerably higher in the SHR (190 +/- 4 mmHg) than they were in the WKY rats (138 +/- 2 mmHg). Skin blood flow values at the three nutritive sites were similar in the two species. However, at 44 degrees C, flow was significantly higher at the paw in the SHR (46.8 +/- 3.5 versus 34.3 +/- 2.2 ml/min per 100 g). We attribute this difference to the effect of high perfusion pressure on large arterioles. During the 1-year measurement period, there was no appreciable change in blood flow in the WKY rats. In contrast, the SHR showed a steady progressive decline in skin blood flow at all sites. The largest decline was at the paw with a rate of fall of about 2.4%/month. After 1 year, there was no difference between paw blood flow in the SHR (27.5 +/- 1.8 ml/min per 100 g) and in the WKY rats (27.6 +/- 1.9 ml/min per 100 g). CONCLUSIONS: Skin blood flow reserve falls in response to chronic hypertension. The rate of fall is greater at sites with significant arteriovenous perfusion that at nutritive sites.

Animals↗
PubMed1994

Cortical porosis under plates. Reaction to unloading or to necrosis?

Cortical porosis under plates used for the fixation of fractures is often attributed to the interference of the plates with cortical perfusion, resulting in necrosis, which in turn induces remodeling. To our knowledge, no histomorphometric studies have been published that demonstrate the correlation between cortical necrosis and porosis. The objective of this study was to test the hypothesis that cortical necrosis is related to changes associated with porosis. Standard and railed plates were applied to intact femora in ten dogs. Histomorphometric studies done at eight and twenty-four weeks after insertion of the plate failed to show a significant positive correlation between necrosis and porosis irrespective of the type of plate used. Porosis was always greater in the inner cortical sector, where no increased necrosis was noted, than in the outer cortical sector, where necrosis was present.

Animals↗
PubMed1992

Variable expression of the interleukin-2 receptor alpha chain and MYC genes in lymphocytes from renal cell carcinoma patients treated with interleukin-2.

We have studied the expression of the interleukin-2 receptor alpha chain, c-MYC and L-MYC genes in lymphocytes obtained from four renal cell carcinoma patients undergoing an interleukin-2 clinical trial. Two of these patients exhibited stable disease after the interleukin-2 therapy and two exhibited progressive disease. Analysis of mRNA levels by dot blot hybridization indicated that changes in the expression of both the interleukin-2 receptor alpha chain and c-MYC genes were erratic and varied widely between patients. L-MYC expression was not observed in any sample. There appeared to be little correlation between the changes in gene expression and parameters such as thymidine incorporation, the proportion of CD25 positive cells present or cytotoxic activity. The situation in vivo therefore appears to be more complex than would be predicted from in vitro studies.

Antigens, CD↗
PubMed1992

Signal transduction in murine B16 melanoma cells.

The relationship between lung colonization and signal transduction was investigated for six B16 melanoma variants. A range of experimental metastatic potential (as determined by lung colonization), forskolin-stimulated cyclic AMP accumulation and FCS-stimulated protein kinase C activity was found. The major findings were that: (1) cells with the highest agonist-stimulated cyclic AMP production were those with the highest level of membrane-associated protein kinase C activity; (2) clones which differed in protein kinase C levels and distribution did so in the presence but not in the absence of foetal calf serum; and (3) no simple relationship was seen between either signal transduction system and lung colonization for all six variants. Altered ras expression was also excluded as an explanation for the differences in signal transduction and lung colonization potential which were observed. We conclude that differences in signal transduction in vitro between these cells do not relate simply to lung colonization potential in vivo.

Animals↗
PubMed1991

Simple bone cysts. The effects of methylprednisolone on synovial cells in culture.

Ten years ago, a protocol using Depo-Medrol injections was developed for the treatment of unicameral bone cysts. This concept, designed by tumor surgeons and based on theory, has been cautiously approached. However, reproducible results have gradually increased clinical acceptance. Understanding the healing process has been restricted because of the lack of an experimental model. In an attempt to elucidate this mechanism of healing, a cell culture model was used to investigate the effects of methylprednisolone on synovial cells. Initially, three doses of the drug were tested and maximal changes were noted with the concentration of 40 mg/ml. Changes were then quantified by morphology, DNA assay, cell protein analysis, and electron microscopy. Results suggest that methylprednisolone may have a direct effect on the cellular component of unicameral bone cysts.

Bone Cysts↗
PubMed1990

Refractures after forearm plate removal.

Debate continues over the need for removal of internal fixation devices. Nowhere has this been more intense than in the area of forearm fractures. Although basic biologic principles would dictate that fixation interferes with bone physiology, clinical experience has taught surgeons that every reoperation has potential complications. We therefore retrospectively reviewed all patients undergoing forearm plate removal during a 5 1/2-year period. There were four subsequent refractures in 63 patients, for an incidence of 6%. Factors that appeared to influence the refracture rate were degree of initial displacement and comminution, physical characteristics of the plate, early removal, and lack of postremoval protection.

Adult↗
PubMed1989

Femoral fractures in Paget's disease.

Since the original description of osteitis deformans, the treatment of femoral fractures occurring in this disease process has been difficult. A retrospective study of 35 fractures treated over an 8-year period was undertaken to identify the factors that influenced the results. The fractures were classified according to four fracture patterns: subcapital, intertrochanteric, subtrochanteric, and shaft. Chart and radiographic analyses were then performed. The results identified subtrochanteric fractures, occurring in a somewhat younger population, to be the problem fracture. The other three fracture groups did well with standard methods of treatment. Uncemented arthroplasties were not successful; this correlates with the known bone physiology of this age group and this disease process. Blood loss was not statistically significant in any group, although it was greater in the subtrochanteric population. Preoperative assessment by bone scanning and preoperative medical treatment is recommended in the subtrochanteric fracture group.

Adult↗
PubMed1986

Reassembling scattered and mixed human bones by trace element ratios.

Trace metal ratios in human bones were examined to determine if there were ratios that were sufficiently consistent within an individual yet varying sufficiently from the bones of another individual so that bones in a mixed grave could be reassembled. The concentrations of 21 elements sampled at 54 places on 30 human bones in each of 5 skeletons indicated that the magnesium/zinc ratio was the most reliable and that the zinc/sodium, magnesium/sodium, and chromium/sodium ratios could be used as supplements to help reassemble human bones belonging to the same individual after all standard techniques had been used.

Adult↗
PubMed1985

Comparison of health problems related to work and environmental measurements in two office buildings with different ventilation systems.

A cross sectional survey investigating "building sickness" was carried out in two buildings with similar populations of office workers but differing ventilation systems, one being fully air conditioned with humidification and the other naturally ventilated. The prevalence of symptoms related to work was assessed by a questionnaire administered by a doctor. A stratified, randomly selected sample of workers was seen (84% response). Building sickness includes several distinct syndromes related to work, most of which were significantly more common in the air conditioned building than the naturally ventilated building--namely, rhinitis (28% v 5%), nasal blockage and dry throat (35% v 9%), lethargy (36% v 13%), and headache (31% v 15%). The prevalence of work related asthma and humidifier fever was low and did not differ significantly between the two buildings. An environmental assessment of the offices was performed to attempt to identify possible factors responsible for the differences in the prevalence of disease. Globe temperature, dry bulb temperature, relative humidity, moisture content, air velocity, positive and negative ions, and carbon monoxide, ozone, and formaldehyde concentrations were all measured. None of these factors differed between the buildings, suggesting that building sickness is caused by other factors.

Air Conditioning↗
PubMed1985

Occupational asthma in a factory with a contaminated humidifier.

Thirty five printers who had work related wheeze, chest tightness, or breathlessness kept two hourly records of their peak expiratory flow for at least two weeks. They all worked in a factory supplied by air from contaminated humidifiers. The peak flow records showed consistent work related deterioration in 15 workers, nine of whom had a diurnal variation in peak flow exceeding 20%. Ten workers kept further records after the humidifiers had been cleaned, other work practices remaining unchanged. There was substantial improvement in all 10 workers, implying that material from the contaminated humidifier was the cause of the work related changes in peak flow. The patterns of work related changes in peak flow fell into four groups: falls maximal on the first work day, falls maximal midweek, falls equivalent each work day, and falls progressive throughout the working week. Three quarters of this last group had immediate prick test responses to humidifier antigen, which were negative in all the others with work related changes in peak flow. This suggests that the progressive daily deterioration pattern alone is due to an IgE mediated response to humidifier antigens. A large range of microorganisms was identified in the humidifiers. No single microorganism appeared to be the antigen responsible for the precipitating antibody seen in 75% of the study population.

Air Conditioning↗
PubMed1985

Brown adipose and metabolic features of chronic diet-induced obesity.

Half of the 3-mo male Sprague-Dawley rats fed a high-fat (DIO) diet for 5 mo became obese and had increased carcass lipid (106%) and plasma insulin levels (61%), despite 8% less total energy intake than chow-fed controls. Their interscapular brown adipose tissue (IBAT) was 52% heavier with 45% more lipid and larger uni- and multilocular cells. Norepinephrine turnover was normal in their hearts, pancreases, and aortas but undetectable in IBAT where in vitro lipolysis, but not O2 consumption (VO2), was enhanced. Half the rats fed the DIO diet ate 17% fewer calories, gained weight equally to controls, but still had 34% more carcass lipid. Their IBAT was heavier, contained 103% more protein, with no detectable norepinephrine turnover, whereas maximal lipolysis was 73% lower and maximal VO2 was the same or even lower than controls. IBAT VO2 was stimulated by switching 8-mo chow-fed controls to the DIO diet for 7 days (which caused a 480% greater weight gain) but not by switching 8-mo obese rats to chow for 3 days. Therefore metabolic efficiency was increased while BAT VO2 and norepinephrine turnover were unchanged or reduced compared with controls by either chronic obesity or a high-fat diet.

Adipose Tissue, Brown↗
PubMed1983

The effects of metal plates on post-traumatic remodelling and bone mass.

The long-term effect of stainless steel and titanium alloy plates on structural remodelling and bone mass of osteotomised canine femora was studied and the effects of early and late removal of plates were compared in 27 adult Beagles. Radiological, histological, histomorphometric and tetracycline fluorescence studies led to three conclusions. First, the continuous (60 weeks) presence of plates, irrespective of their composition, delays remodelling and leads to a reduction of bone mass. This loss is significantly greater under stainless steel plates. Secondly, the removal of plates at eight weeks leads during the 52 ensuing weeks to a marked and widespread structural remodelling and to a return to normal bone mass, irrespective of the type of plate used. However, remodelling is more intense after titanium alloy plates have been used; it is not complete 60 weeks after osteotomy. Thirdly, removal of plates at 40 weeks activates remodelling during the ensuing 20 weeks to a lesser degree and to a more limited extent than early plate removal. The clinical significance of this study is that less rigid but stable internal fixation permits the radiological assessment of healing and thus the determination of the optimal moment for removal of the plates. It also reduces the degree of bone loss should the plate be left in situ for any reason.

Alloys↗