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Biomedical subjects

L Martin

Publications and source records attributed to L Martin.

At least 253 records · Page 14Linked to original sources
PubMed1997

Is a histological section representative of whole tumour vascularity in breast cancer?

The assessment of a tumour's angiogenic potential, by measuring the microvessel density in histological sections, assumes that a 4-microm section is representative of whole tumour vascularity. This study has examined this assumption by comparing the vessel density found radiologically, after injecting specimens with contrast, with that found immunohistochemically. Twenty-one breast angiograms were performed following mastectomy for carcinoma and graded 1-3 for vessel density. Sections (4 microm) from these carcinomas were labelled for endothelial cells using anti-CD34, and the vessel counts were compared with the radiological grades. A significant correlation was found between the densities (P < 0.003, Kruskal-Wallis one-way ANOVA). We therefore conclude that the microvessel density measured in histological sections is representative of whole tumour vascularity.

Adult↗
PubMed1997

Examining the technique of angiogenesis assessment in invasive breast cancer.

The intensity of angiogenesis as measured by the density of microvessels has been reported to be associated with a poor prognosis in invasive breast cancer in some, but not all, studies. The reasons for these discrepancies may be variations in the methodologies used. The monoclonal antibody used to identify the microvessels, the number of high-density areas or 'hotspots' counted and the type of value taken for statistical analysis (highest count or mean count) have varied between the different studies. We have assessed which of the three commonly used monoclonal antibodies provides the best visualization of microvessels in invasive breast cancer and have used methods that give reproducible data for the optimum number of 'hotspots' to count for each reagent. Thus, microvessels in formalin-fixed paraffin-embedded specimens from 174 primary breast cancers were immunohistochemically stained with monoclonal antibodies to FVIIIRAg, CD31 and CD34 and ten fields counted at 200 x magnification for each antibody. The highest count and the mean value of the highest of three, five and ten counts were used to examine the relationship between the density of microvessels and overall survival of patients with a median follow-up time of 7.1 years. Antibodies to CD31 and CD34 identified more vessels than antibodies to FVIIIRAg (median highest count per mm2: CD31 = 100, CD34 = 100, FVIIIRAg = 81). The monoclonal antibody to CD31, however, was the least reliable antibody, immunohistochemically staining only 87% of sections compared with 98% for the monoclonal to CD34 and 99% for the monoclonal to FVIIIRAg. There was a high degree of correlation between the number of vessels stained by the different antibodies, though there were some considerable differences in actual counts for serial sections of the same specimen stained by the different antibodies. Patients could be divided into two groups corresponding to those with high microvessel densities and those with low microvessel densities. Using Kaplan-Meier survival curves, there was a close association for all three antibodies between vessel density and survival whichever method of recording the highest vessel densities was used. Using log-rank tests and Cox's regression analysis, anti-CD34 gave the most significant results of the three antibodies, whereas a simple cut-off at the 75th percentile for the high and low groups produced the best association with patient survival. For anti-CD34 the highest microvessel density (P = 0.0014) and the mean value of the highest three microvessel densities (P = 0.004) showed a good correlation with patient death, whereas for anti-CD31 (P = 0.008) and anti-FVIIIRAg (P = 0.007) the highest count gave the best correlation using Cox's regression analysis.

Adolescent↗
PubMed1997

Three-dimensional joint moments analysis in a vertical quadrupedal posture associated with a leg release.

This study reports on rock climbers biomechanical adjustments following a leg release from a quadrupedal vertical initial stance. Six climbers of international level have been studied. They were asked to maintain a quadrupedal posture on artificial holds equipped with strain gauges and then to release their right foot. The results show that all the rock climbers adjust differently the vertical forces and the horizontal forces on the holds. They distribute the vertical forces over the three remaining holds and the horizontal forces over the controlateral holds. A quasi-static three-dimensional multi-segment model was used to produce the net reaction forces and joint moments at each joint. Moment results enhance the role of the controlateral limbs, particularly the left leg. The gravity seems to be counteracted at the left knee joint, while body balance seems to be managed at the left hip and ankle joints.

Adult↗
PubMed1997

Effects of the type of recovery training on the concentric strength of the knee extensors.

The aim of this study was to examine the effects of specific concentric and eccentric training on concentric muscular strength following an initial standardized period of excessive training that combined concentric and eccentric actions. For a period of 12 weeks, 37 young elite female basketball players performed standardized training, which included concentric and eccentric actions at 70% and 110% of one-repetition maximum (1-RM), respectively. They were then divided into three groups that followed 12 week programmes which included concentric (C-E/C, n = 13), eccentric (C-E/E, n = 13) or a combination of both concentric and eccentric (C-E/-E, n = 11) exercises. The standardized and specific training programmes consisted of 16 and 8 sets of eight repetitions respectively, performed four times a week. Eleven players who did not participate in either the standardized or specific training programmes served as controls (n = 11). Following the initial 12 weeks of standardized training, the concentric strength of the knee extensors was evaluated isokinetically and using leg-press and squat-jump tests. Significant (P < 0.05) reductions in isokinetic torque, and leg-press and squat-jump performance, were seen. The C-E/C group showed significant (P < 0.05) increases in isokinetic torque, and leg-press and squat-jump performance, after 24 weeks of training when compared with pre-training values. Conversely, no significant differences were noted for the C-E/E and C-E/C-E groups. These findings confirm the mode specificity principle, as only the concentric specific training programme improved the concentric strength of the knee extensors.

Adolescent↗
PubMed1997

Antimicrobial protection of the mouse testis: synthesis of defensins of the cryptdin family.

We report the synthesis by mouse testicular cells of antibiotic peptides related to the defensins secreted by the Paneth cells of the intestinal epithelium. A Sertoli cell-derived line (15P-1), Sertoli cells in primary cultures, and explanted testicular tissue in culture medium were observed to release protease-sensitive material with a broad-spectrum antibacterial activity. The activity of 15P-1 culture medium was increased 10- to 50-fold in the presence of fractions enriched in round spermatids and of nerve growth factor. Two series of results suggest that this activity may correspond to the release by testicular cells of defensin peptides, and specifically, of peptides of the cryptdin family first identified in the Paneth cells of intestinal crypts. First, a characteristic nucleotide sequence corresponding to the conserved first exon of the mouse cryptdin and cryptdin-related (CRS) genes was evidenced in the RNA of 15P-1 cells and of the testis. Second, immunohistochemical analysis demonstrated the presence of cryptdins of the cryp-1, -2, -3, -6 group in 15P-1 cells, and identified two distinct localizations in the testis. Inside the seminiferous tubule, these cryptdins were found accumulated in Sertoli cells at stages corresponding to the maturation of spermatids. In the interstitial space, Leydig cells also contained immunoreactive cryptdins.

Animals↗
PubMed1997

Detection of identical ribotypes of Porphyromonas gingivalis in patients residing in the United States, Sudan, Romania and Norway.

Porphyromonas gingivalis has been isolated from periodontitis lesions in subjects from many geographical locations. The purpose of this investigation was to determine whether similar ribotypes of P. gingivalis could be detected among strains isolated in different countries. A total of 198 isolates of P. gingivalis were obtained from 52 periodontitis patients in Boston (130 isolates), Bergen, Norway (17 isolates), Khartoum, Sudan (26 isolates), and Bucharest, Romania (25 isolates). DNA was isolated from each strain, cut separately by the restriction endonucleases KpnI and PstI. The resulting preparations were subjected to electrophoresis in a 0.8% agarose gel using a Tris-acetate EDTA buffer. Uncut lambda and a 1000-bp fragment of 16S rRNA were included as internal standards in each lane. In addition, a HindIII digest of lambda was present in a separate lane in each run. The DNA fragments were transferred to a nylon membrane by downward capillary transfer. 16S rRNA bands were detected using a 1000-kb digoxigenin-labelled probe generated by a polymerase chain reaction. At the same time, a digoxigenin-labelled probe to lambda was employed to detect the internal and molecular weight standards. The bands were detected using antibody to digoxigenin conjugated to alkaline phosphatase and chemiluminescence. The positions of the bands relative to the internal standards were determined and normalized to correct for run-to-run variations, and the molecular weight of each band was determined by comparison with standards within each gel. The resulting data for the 2 enzymes were combined and subjected to cluster analysis using an average unweighted linkage sort. In some instances, isolates that appeared to be of identical ribotype using one endonuclease gave different ribotypes using the other. Strains of P. gingivalis within a subject were usually identical, except for 3 patients who harbored 2 different ribotypes/individual. All subsequent analyses employed a single ribotype strain for each subject. A total of 32 ribotypes were observed for isolates from distant countries. A total of 11.5% of the patients had isolates exhibiting the same ribotype: ribotype 7a. Identical ribotypes of P. gingivalis can be recovered from subgingival plaque samples of periodontitis patients in different countries.

Bacterial Typing Techniques↗
PubMed1997

Cataract and high-pass resolution perimetry.

The present study describes the influence of cataract on high-pass resolution perimetry results. Twenty-five otherwise healthy patients were examined before and after cataract surgery. Their preoperative visual acuities ranged from 0.1 to 0.8 and their mean resolution thresholds from 3.9 to 12.3 dB. Both elevated mean thresholds and local visual fields defects were observed. In patients with low-grade cataract, i.e. preoperative visual acuity 0.3 to 0.65, the mean improvement in perimetric results after operation was approximately 1 dB. In patients with higher degrees of lens opacity, visual acuity 0.1 to 0.25, the difference between pre- and postoperative perimetry results showed a wide range, 1.4-6.2 dB. In conclusion, cataract induced different types of visual field defects. The general threshold increase due to low-grade cataract (VA > or = 0.3) could be compensated for by subtracting 1 dB from the measured value.

Aged↗
PubMed1997

Management of ocular hypertension and open angle glaucoma: clinical practice and computer-assisted decision-making.

PURPOSE: To evaluate the feasibility of computerized decision support in the management of patients with open angle glaucoma or ocular hypertension. METHOD: Based on a Swedish consensus document a computer program was developed, which provided one of 25 different recommendations for appropriate action. In 373 patient visits to seven different eye clinics, the program's recommendations were compared to the actual decisions made by the responsible ophthalmologists. RESULTS: Notable differences were observed between the clinics' management strategies, especially regarding follow-up frequency and start or increase of anti-glaucoma treatment. The program's recommendations conformed with the clinical decisions in 23 to 92% of the cases when a standard management strategy was simulated. The concordance increased to 93 to 100%, when policy differences between the clinics were taken into account. CONCLUSION: Clinical decision-making in the management of patients with ocular hypertension or open angle glaucoma can be implemented in a computer program. The optimum management protocol remains to be defined.

Aged↗
PubMed1997

Detection of Chlamydia trachomatis in urine samples by nucleic acid tests: comparison with culture and enzyme immunoassay of genital swab specimens.

Two commercially available nucleic acid-based tests, ligase chain reaction (LCR; Abbott Laboratories) and PCR (Roche Diagnostics), for the detection of Chlamydia trachomatis in male and female urine samples were compared with culture and enzyme immunoassay (EIA) (Microtrak; Syva) for C. trachomatis detection in genital samples. The samples were collected from 1,005 patients who attended a sexually transmitted disease clinic. In this study population, the prevalence of the infection was 4%. Specimens which were reactive in any of the tests were retested with a different PCR test using primers directed against the major outer membrane protein gene. With a "gold standard" of a positive culture, or any other positive test result if it was confirmed by an independent test, the Roche PCR (95% sensitive, 99.9% specific) was more sensitive than the LCR (75% sensitive, 100% specific) (chi2, P < 0.0001) while both tests were more sensitive than culture (58% sensitive, 100% specific) or EIA (45% sensitive, 100% specific) (chi2, P < 0.001). The Roche PCR and Abbott LCR tests of urine identified 65% and 30% more positive patients, respectively, than did testing by culture of urethral or cervical specimens. Nucleic acid testing of urine specimens for C. trachomatis is a more sensitive and convenient method for the detection of genital infection.

Bacteriological Techniques↗
PubMed1997

Investigation of gray-headed flying foxes (Pteropus poliocephalus) (Megachiroptera: Pteropodidae) and mosquitoes in the ecology of Ross River virus in Australia.

Entomologic and virologic factors were investigated to determine whether gray-headed flying foxes (Pteropus poliocephalus) from Indooroopilly Island, Brisbane, Australia could be vertebrate hosts of Ross River (RR) virus. Aedes funereus was the most abundant mosquito species with 6,300-38,700 females per light trap night in the flying fox camp containing gray-headed, black (P. alecto), and little red (P. scapulatus) flying foxes. Sixteen Ae. funereus blood meals from this collection were analyzed by hemoglobin electrophoresis and were found to be from P. alecto. From pledget feeding with RR virus, the infectious dose required to infect 50% of wild caught Ae. funereus was log10 4.2 50% tissue culture infectious doses per mosquito, with a transmission rate to mice of 17% at 9-10 days post infection. Experimental infection of 10 juvenile P. poliocephalus produced viremias of low titer in five animals, with a duration of 1-4 days and a mean of two days. Three percent of colonized Ae. vigilax that fed on the 10 animals during this period became infected. One of the five viremic flying foxes and two of the five aviremic animals produced a detectable immune response by either neutralization or hemagglutination-inhibition tests. Based on the low to moderate vector competence of Ae. funereus for RR virus, and evidence that P. poliocephalus is a poor vertebrate host of RR virus, it is unlikely that RR virus transmission would be maintained between these two species, but it could be maintained by other more competent vector/host pairs.

Aedes↗
PubMed1997

'Shared care' and computer assistance in glaucoma management.

Primary open angle glaucoma afflicts 1-2% of people over 50 years of age. The diagnosis relies on a number of examinations, many of them performed by ophthalmic nurses, and the care of glaucoma patients has become one of their main tasks. A knowledge-based system for decision support in glaucoma management has been developed and validated. The aim of the current study is to evaluate the influence of computerised decision support on a 'shared care' organisation for the management of glaucoma patients.

Case Management↗
PubMed1997

Spontaneous rupture of abdominal aortic aneurysms in patients with non-related blunt traumatic injuries.

As the population ages, abdominal aneurysms are expected to increase in frequency, as well as in the number of elderly patients involved in automobile trauma. Therefore, the number of incidental abdominal aortic aneurysms found in elderly trauma patients should be expected to rise. The purpose of this paper is to report two cases of ruptured abdominal aortic aneurysms found after nonassociated blunt trauma. We review the literature and discuss possible etiologic factors and management associated with this problem.

Accidents, Traffic↗
PubMed1997

[Obliterative arteriopathy in chronic rejection after hepatic transplantation. Search of cytomegalovirus genome by in situ hybridization and viral antigens by immunohistochemistry].

OBJECTIVES: This study was performed to assess the role of cytomegalovirus in the parietal infection of intrahepatic arteries in the pathogenesis of obliterative arteriopathy from chronic rejection after orthotopic liver transplantation. METHODS: We studied two groups of liver transplants by in situ hybridization and immunohistochemistry: group 1, including 10 liver grafts with obliterating arteriopathy, and group 2 including 7 liver grafts without any arterial disorders. The results were correlated with clinical data (cytomegalovirus infection and acute rejection). RESULTS: By in situ hybridization, cytomegalovirus DNA was identified in the media in 70% of transplants in group 1 and 42% in group 2. Detection of immediate early and late antigens by immunohistochemistry was negative. Cytomegalovirus infections were often associated with acute rejection. CONCLUSION: These results suggest that cytomegalovirus detected in arteries is latent, and that cytomegalovirus probably does not play a role in the pathogenesis of chronic rejection obliterative arteriopathy.

Adult↗
PubMed1997

The influence of systemic lupus erythematosus on fetal development: cognitive, behavioral, and health trends.

In 1985, Gualtieri and Hicks proposed the immunoreactive theory to explain the higher prevalence of childhood neurodevelopmental disorders in males. The theory claimed that male fetuses are more antigenic to mothers, resulting in increased immunologic attack on the developing central nervous system, and increased probability of atypical brain development. Individuals with systemic lupus erythematosus (SLE) provide a unique situation in which to investigate this theory. We evaluated the parent-reported prevalence of five developmental problems (stuttering, other speech problems, hyperactivity, attention deficit, and reading problems) in two groups: 154 individuals ages 8-20 years born to women with SLE, drawn from six cities, and 154 controls of comparable age and sex whose mothers did not have SLE. Controls were drawn from a comparison group ascertained from randomly selected schools in one of the cities. Questions about handedness, immune disorders, and pregnancy and birth complications were also evaluated. Children of SLE mothers were shown to have more evidence of developmental difficulties, immune related disorders, and nonrighthandedness. For developmental problems, these findings were most marked in male children of SLE mothers. These results suggest that maternal immunoreactivity, as represented by women with SLE, may present a special risk factor for subsequent learning difficulties in their children, particularly males.

Adolescent↗