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Biomedical subjects

L Martin

Publications and source records attributed to L Martin.

At least 19 recordsLinked to original sources
PubMed2007

Muscle adaptation patterns of children with a trans-tibial amputation during walking.

BACKGROUND: Many studies have shown that trans-tibial amputation involves modifications of resultant muscle patterns during gait. However, these experiments did not estimate the contribution of simultaneous agonist and antagonist muscle action (co-contraction) during gait tasks. Diminution of co-contraction could create joint instability and, thus, change joint integrity, which is particularly important in the etiology of degenerative diseases, such as osteoarthritis, present at the knees of amputated limbs, and particularly in non-amputated limbs. The purpose of this study was to determine if there is any difference in the production of co-contraction about the knee between able-bodied children and children with a trans-tibial amputation during gait. METHODS: Six children with a trans-tibial amputation vs. six able-bodied children paired for gender, age, weight and height participated in this study. Four one-way ANOVAs (P<0.05) were used to observe differences in resultant, agonist and antagonist moments, power, and co-contraction index during different phases of gait between able-bodied children limbs, the amputated and the non-amputated limbs of children with trans-tibial amputation. FINDINGS: Children with a trans-tibial amputation modified muscle patterns at their amputated limb and produced smaller co-contraction (P<0.05) during single limb support, for both the non-amputated and amputated limbs when compared to able-bodied children. INTERPRETATION: These results suggest that children with a trans-tibial amputation altered their muscle patterns to perform locomotion. These changes produced a diminution of co-contraction during single limb support for both the amputated and non-amputated limbs and, thus, could create joint instability.

Amputation, Surgical↗
PubMed2007

Morphologic and histologic comparisons between in vivo and nuclear transfer derived porcine embryos.

Nuclear transfer (NT) is an inefficient but invaluable tool of the biotechnology industry. This study looked at abnormalities associated with peri-implantation NT porcine embryos. Four experimental groups were examined: nonpregnant animals, in vivo pregnant animals, NT recipients, and manipulation control embryos (MC). Embryos (Day 10, 12, or 14) were evaluated for embryonic disc diameter, gross morphology, nucleoli density, and mitotic figure index. Day 12 (P < or = 0.03) and Day 14 (P < or = 0.01) NT embryos had increased numbers of nucleoli, and Day 14 NT embryos had an increased (P < or = 0.03) mitotic index compared to in vivo and MC embryos. In vivo produced Day 14 embryos had increased (P < or = 0.01) disk diameters when compared to other embryos except for MC Day 14, which also showed increases (P < or = 0.01) in disk diameter except when compared to in vivo produced Day 12 and Day 14 embryos. In vivo produced Day 12 had greater (P < or = 0.03) disk diameters when compared to NT and MC embryos except for MC Day 14, and in vivo produced Day 14 embryos, which had a significantly increased (P < or = 0.01) disk diameter. In vivo produced Day 14 embryos were morphologically more advanced (P < or = 0.01) than Day 14 NT and MC counterparts. NT embryos develop at a slower rate than their in vivo produced counterparts. The increase in nucleoli and mitotic index of NT embryos suggest the cell cycle may be affected or the NT embryos are employing other means to compensate for slow development. The techniques used during NT also appear to compromise embryo development.

Animals↗
PubMed2006

Intraocular pressure before and after visual field examination.

PURPOSE: To evaluate the influence of visual field (VF) examinations using modern techniques with short examination times on the intraocular pressure (IOP). METHODS: Sixty-one consecutive patients, aged 28-90 years, 40 women and 21 men, were examined. Forty patients were treated for glaucoma and 21 were untreated patients with ocular hypertension or suspected glaucoma. Twenty-one subjects were examined using the Humphrey Field Analyzer, using SITA programs, and 40 with high-pass resolution perimetry (HRP). Goldmann applanation tonometry was performed immediately before and after the VF examinations. RESULTS: A difference in IOP of more than 2 mm Hg before and after the VF examination was observed in 14 of the 61 patients (23%). The maximum change in each direction was 4 mm Hg. The mean differences were not significant. All eight subjects with increasing IOP after VF examinations were examined using the HRP technique (P=0.04). CONCLUSION: Modern VF techniques with short examination time do not seem to significantly influence IOP.

Adult↗
PubMed2006

[Disposable vs reusable laryngeal mask airway: a cost-minimization analysis].

JUSTIFICATION: According to French regulations concerning the risk of Creutzfeldt-Jakob disease transmission, traceability procedures of all sterile medical devices which need to be reused are mandatory. Despite sterilization processes, the reusable laryngeal mask airway (LMA) prion disease transmission remains possible. As a result, the disposable LMA has been introduced. OBJECTIVE: Assuming clinical equivalence was achieved, the cost of disposable vs reusable LMA was studied in a university hospital. STUDY DESIGN: A Cost-minimization analysis of disposable vs reusable laryngeal mask airway was realised. METHODS: Disposable LMA cost was calculated as the sum of product cost and elimination cost. Reusable LMA were autoclaved after hospital purchasing in two separate sterilizing processing units of the same hospital. Reusable LMA cost was determined combining materiel and labor costs. RESULTS: The reusable LMA cost depended on the sterilizing processing unit concerned and varied between 9.59 Euros and 9.69 vs 8.38 Euros for the single-use LMA. CONCLUSION: With the cost savings made possible by use of disposable LMA in both labor and consumables, this practice should be considered.

Cost Control↗
PubMed2006

Linear growth and body mass index in pediatric patients with Cushing's disease or simple obesity.

BACKGROUND: Increasing prevalence of childhood obesity has resulted in an accelerating rate of referrals of overweight patients to pediatric clinics for exclusion of endocrine or metabolic etiologies. The exclusion of Cushing's disease (CD) requires complex and potentially invasive investigations. OBJECTIVE: To evaluate the sensitivity of accurate measurements of height, weight and body mass index (BMI) in discriminating between simple obesity and CD. METHODS AND PATIENTS: Height, weight and BMI were measured at diagnosis in 25 patients with CD; 14 males, 11 females, mean age 12.9 yr (6.4-17.8) and 41 patients with simple obesity (SO), defined as BMI >2.0 SD; 20 males, 21 females, mean age 9.4 yr (3.5-15.6). RESULTS: Mean (+/-SE) BMI SDS in the CD patients was 2.41+/-0.5 and in the SO patients 3.71+/-1.3. Height SDS in the CD patients was -1.88+/-0.24 and in the SO patients 1.18+/-0.19 (p<0.05). The mean (+/-SE) BMI SDS to height SDS ratio was significantly decreased in the CD compared with the SO patients; -1.81+/-0.54 vs +0.90+/-1.17 (p<0.0001). CONCLUSIONS: Simple, accurate measurement of height and BMI SDS values provides a quick, and sensitive diagnostic discriminator in pediatric patients with CD or SO, thus potentially avoiding complex investigations.

Adolescent↗
PubMed2006

Chimerism in lymphoid tissues and donor-specific antibody response after injection of allogenic splenic dendritic cells from Fischer rats to Lewis recipients.

The aim of this work was to study cellular chimerism achieved in lymphoid tissues and production of antidonor lymphocyte antibodies after injection of splenic dendritic cells (DCs) from Fischer F344 rats to Lewis recipients, a model of chronic rejection. DCs isolated from the spleen expressed OX62 (95%), CD80 (70%), and CD86 (80%). Two doses of these nonplasmacytoid splenic DCs from Fischer rats (2 x 10(6) and 5 x 10(6)), which had been labeled ex vivo with a TRITC fluorochrome (PKH26), were injected to Lewis recipients. Using fluorescence microscopy TRITC positive cells were localized at day 15 and day 45 in frozen sections from spleen, thymus, mesenteric lymph nodes, heart, liver, kidney, and skin (n = 5 per group). Donor-specific antibodies were sought with flow cytometric crossmatches in serum samples taken at 7, 15, 30, and 45 days. TRITC-positive DCs were essentially localized in the spleen, the thymus, and lymph nodes of Lewis recipients. The majority of DCs were detected in the spleen (14.9 +/- 3.3 and 14.3 +/- 0.9 DCs/per high power field respectively at day 45). A significant number of DCs was also detected in the thymus and mesenteric lymph nodes at both times. Only some scattered TRITC-positive cells were observed in other organs. The number of DCs was stable over time and did not depend on the injected dose. A positive flow cytometric cross-match was observed at day 30 in all recipients independent of the injected dose. These data showed that 2 x 10(6) mature, nonplasmocytoid DCs from F344 rats injected to Lewis recipients induced stable chimerism in primary and secondary lymphoid organs and a humoral response to donor antigens.

Animals↗
PubMed2006

Expression of TGFbeta-1 and Type I TGFbeta-receptor on sequential biopsies of renal transplants with chronic allograft nephropathy.

The aim of this study was to determine the expression of transforming growth factor-beta (TGFbeta)-1 and type I TGFbeta-receptor on sequential biopsies from renal transplants with and without chronic allograft nephropathy. Twenty-four renal transplant recipients entered the study. They underwent sequential biopsies performed before (T1: 1.44 +/- 1.2 months) and 6 months after (T2: 15.96 +/- 7.2 months) transplantation. Lesions were graded according to the criteria of the Banff classification. C4d was detected by fluorescence microscopy. Immunohistochemistry was performed in order to identify cells expressing TGFbeta-1 and type I TGFbeta-receptor. In normal renal tissue (n = 4), TGFbeta-1 is expressed by tubular epithelial cells and endothelial cells lining glomerular and peritubular capillaries, whereas type 1 TGFbeta-receptor is expressed by tubular epithelial cells and smooth muscle cells in the media of arteries. In recipients with chronic allograft nephropathy (group 1, n = 14), diffuse epithelial expression of both molecules was found in more patients at T2 than at T1 (42.8% vs 21.4%). In contrast, this pattern of expression remained stable or decreased over time in recipients with long-term normal transplants (group 2, n = 10). Furthermore, type 1 TGFbeta-receptor was detected on the smooth muscle cells of arteries in 12/14 (85.7%) of recipients in group 1 and only in 4/9 (44.4%) of recipients in group 2. No relationship was noticed with regard to C4d deposits. These data suggest that the synthesis of TGFbeta-1 and type I TGFbeta-receptor increases over time in recipients developing chronic allograft nephropathy. Further studies are in progress in order to quantify mRNA of both molecules with real-time polymerase chain reaction.

Activin Receptors, Type I↗
PubMed2006

Prostate specific antigen isoforms and human glandular kallikrein 2--which offers the best screening performance in a predominantly black population?

PURPOSE: Free prostate specific antigen, complexed PSA and human glandular kallikrein 2 have independently been tested against the gold standard of total PSA for prostate cancer screening in largely white populations. With the incidence of prostate cancer much higher in black men, we sought to evaluate these markers simultaneously in a predominantly black population. MATERIALS AND METHODS: A total of 138 men, of whom 108 were black, underwent ultrasound guided biopsy of the prostate for tPSA levels greater than 2.5 ng/ml or an abnormal digital rectal examination. Sera were drawn before biopsy and analyzed for tPSA, fPSA, cPSA and hK2 concentrations using standard methods (hK2 assay is for research use only, not for use in diagnostic procedures). The areas under the receiver operator characteristic curves were determined for each marker as well as biomarker combinations. Additionally, each parameter's specificity, positive and negative predictive values, and theoretical screening efficiency were assessed at or above the 95% sensitivity level. RESULTS: A total of 43 (31.1%) men had prostate cancer by biopsy. While the AUC for %fPSA was statistically the highest (0.822, p <0.001), cPSA offered the highest specificity (31.6%) and positive predictive power (31.7%) of any of the tested biomarkers at comparable sensitivity (greater than 95%). The calculated efficiency of cPSA (51.4%) was also higher than the other markers. Nearly 20% of biopsies would be avoided using cPSA vs standard tPSA screening methods. CONCLUSIONS: Comparing the major PSA isoforms and hK2, cPSA alone appears to offer superior diagnostic discrimination for cancer detection in a predominantly black population.

Black or African American↗
PubMed2006

[Hair darkening close to a patch of frontal fibrosing alopecia].

BACKGROUND: Fibrosing frontal alopecia is scarring form alopecia and is most often seen in menopausal women. It is currently considered as an anatomoclinical form of lichen planopilaris of selective topography. We report a case of hair repigmentation during the course of post-menopausal frontal fibrosing alopecia. CASE REPORT: A 78-year-old woman developed alopecia of the scalp and eyebrows in 1997. Her eyebrows had been white for some ten years. In 1999, she noted repigmentation of a strip of hair at the edge of her scalp, but the rest of her hair remained white. The patient had not been taking any long-term drugs or any hair treatment. Histological examination of the regions of alopecia revealed lesions of lichenoid appearance at the junction with erosion by lymphocytes and keratinocytic necroses of the lower layers of the epidermis. Direct cutaneous immunofluorescence testing was negative. A diagnosis of post-menopausal fibrosing frontal alopecia was made on the basis of the clinical and laboratory evidence. DISCUSSION: 96 cases of post-menopausal fibrosing frontal alopecia have so far been reported in the literature, but to our knowledge, this is the first case combined with or inducing hair repigmentation. The other cases of repigmentation were eliminated by history-taking, and clinical or laboratory examinations. The mechanism of hair repigmentation in our patient could have been the result of a post-inflammatory process.

Aged↗
PubMed2006

Early and severe amyloidosis in a patient with concurrent familial Mediterranean fever and pseudoxanthoma elasticum.

A young woman patient had early and extensive familial Mediterranean fever (FMF)-related amyloidosis and pseudoxanthoma elasticum (PXE). She had the novel G1042S mutation in the ATP-binding cassette subfamily C member 6 (ABCC6) gene, responsible for PXE, and the mutation M694I in MEFV, the FMF gene. Both mutations were homozygous, in agreement with consanguinity in the parents. ABCC6 deficiency may have increased the severity of amyloidosis by increasing the deposition in target tissues of heparan sulphate, which colocalizes spatially and temporally with amyloid proteins, and/or by decreasing the therapeutic activity of colchicine.

ATP-Binding Cassette Transporters↗
PubMed2006

Perception of very small visual stimuli in the fovea: normative data for the Rarebit Foveal Test.

BACKGROUND: Conventional visual tests are not sensitive enough to detect low degree neural damage, as 6/6 (1.0) visual acuity can be upheld with less than two-thirds of the normal number of optic nerve axons. The aim of the current study was to evaluate the physiologic properties of a new computerised test, the Rarebit Fovea Test (RFT), using very small stimuli, by quantifying the effect of age and binocular summation in relation to stimulus luminance. METHODS: The RFT relies on the perception of very small (less than 0.5 minutes of arc) bright stimuli. Two different experiments were performed. 1. Thirty-five subjects (age 19 to 63 years) were tested with five different stimulus luminances, 158, 64, 53, 41 and 33 cd/m(2). 2. Nineteen subjects (age 19 to 63 years) were tested using binocular stimulation to define the binocular summation. RESULTS: Significantly reduced median hit rates were observed at luminances of 53 cd/m(2) or below. Age and mean hit rate correlated negatively at all luminance levels below 158 cd/m(2). The mean hit rate from binocular stimulation, compared to the highest value from monocular stimulation in the same subject, was increased by a factor of 1.54 +/- 0.45 (SD). No age effect was found regarding binocular summation. CONCLUSIONS: The results in the current study indicate that RFT can identify some of the well-known features of the visual system, that is, the effects of age and binocular summation, provided that the stimulus luminance is adequately selected.

Adult↗
PubMed2006

Dermatofibrosarcoma protuberans: a population-based cancer registry descriptive study of 66 consecutive cases diagnosed between 1982 and 2002.

BACKGROUND: Dermatofibrosarcoma protuberans (DFSP) is a rare malignant tumour of the skin, with an estimated incidence of 0.8 to five cases per 1 million people per year. OBJECTIVE: To study epidemiological, immunohistochemical and clinical features, delay in diagnosis, type of treatment and outcome of DFSP from 1982 to 2002. METHODS: Using data from the population-based cancer registry, 66 patients with pathologically proved DFSP were included (fibrosarcomatous DFSP were excluded). Each patient lived in one of the four departments of Franche-Comté (overall population of 1 million people) at the time of diagnosis. The main data sources came from public and private pathology laboratories and medical records. The rules of the International Agency for Research on Cancer were applied. RESULTS: The estimated incidence of DFSP in Franche-Comté was about three new cases per 1 million people per year. Male patients were affected 1.2 times as often as female patients were. The trunk (45%) followed by the proximal extremities (38%) were the most frequent locations. DFSP occurred mainly in young adults between 20 and 39 years of age. Mean age at diagnosis was 43 years, and the mean delay in diagnosis was 10.08 years. Our 66 patients initially underwent a radical local excision. Among them, 27% experienced one or more local recurrences during 9.6 years of follow-up. There was one regional lymph node recurrence without visceral metastases. These recurrences were significantly related to the initial peripheral resection margins. We observed a local recurrence rate of 47% for margins less than 3 cm, vs. only 7% for margins ranging from 3 to 5 cm [P=0.004; OR=0.229 (95%, CI=0.103-0.510)]. The mean time to a first local recurrence was 2.65 years. Nevertheless, there was no death due to the DFSP course at the end of the follow-up, and the final outcome was favourable. CONCLUSION: Our study emphasizes the importance of wide local excision with margins of at least 3 cm in order to prevent local recurrence. However, the recent development of inhibitors of signal transduction by the PDGFB pathway should soon modify the surgical strategy, which is often too mutilating.

Adolescent↗
PubMed2005

Modulation of NMDA receptors by pituitary adenylate cyclase activating peptide in CA1 neurons requires G alpha q, protein kinase C, and activation of Src.

At CA1 synapses, activation of NMDA receptors (NMDARs) is required for the induction of both long-term potentiation and depression. The basal level of activity of these receptors is controlled by converging cell signals from G-protein-coupled receptors and receptor tyrosine kinases. Pituitary adenylate cyclase activating peptide (PACAP) is implicated in the regulation of synaptic plasticity because it enhances NMDAR responses by stimulating Galphas-coupled receptors and protein kinase A (Yaka et al., 2003). However, the major hippocampal PACAP1 receptor (PAC1R) also signals via Galphaq subunits and protein kinase C (PKC). In CA1 neurons, we showed that PACAP38 (1 nM) enhanced synaptic NMDA, and evoked NMDAR, currents in isolated CA1 neurons via activation of the PAC1R, Galphaq, and PKC. The signaling was blocked by intracellular applications of the Src inhibitory peptide Src(40-58). Immunoblots confirmed that PACAP38 biochemically activates Src. A Galphaq pathway is responsible for this Src-dependent PACAP enhancement because it was attenuated in mice lacking expression of phospholipase C beta1, it was blocked by preventing elevations in intracellular Ca2+, and it was eliminated by inhibiting either PKC or cell adhesion kinase beta [CAKbeta or Pyk2 (proline rich tyrosine kinase 2)]. Peptides that mimic the binding sites for either Fyn or Src on receptor for activated C kinase-1 (RACK1) also enhanced NMDAR in CA1 neurons, but their effects were blocked by Src(40-58), implying that Src is the ultimate regulator of NMDARs. RACK1 serves as a hub for PKC, Fyn, and Src and facilitates the regulation of basal NMDAR activity in CA1 hippocampal neurons.

Amino Acid Sequence↗
PubMed2005

Cellular localisation of survivin: impact on the prognosis in colorectal cancer.

PURPOSE: The present study was designed to determine whether the nuclear or cytoplasmic expression of survivin, was related to clinicopathological parameters and survival in sporadic colon carcinomas. METHODS: Western blotting of cell fractions and immunocytochemical methodology were used in five human colon cancer cell lines. Immunohistochemical study was performed in formalin-fixed paraffin-embedded section from 46 patients with sporadic colorectal adenocarcinomas with a polyclonal antibody directed against survivin. Apoptotic index was evaluated by using the M30 antibody. Survival rates were estimated by the Kaplan-Meier method and compared using the log-rank test. Multivariate survival analysis was performed by the Cox proportional hazards model. RESULTS: Western blotting and immunocytochemistry analyses confirmed that survivin could be detected both in the nucleus and the cytoplasm. Immunohistochemical analysis demonstrated that 39% of tumours expressed survivin in the nucleus and 41% in the cytoplasm. No relationship was observed between survivin expression and clinicopathological features. Unexpectedly, the apoptotic index appeared to be linked with high survivin nuclear expression. Overall, 3-year observed survival rate was 73% in patients with cytoplasmic survivin expression versus 48% for negative expression (P = 0.14). Survival was 72% versus 50% for positive nuclear survivin expression versus negative (P = 0.16). After adjustment for age and stage, cytoplasmic survivin expression was a significant prognostic factor. A high level of expression was associated to a better survival: RR = 0.35 [0.13-0.98], P = 0.045. CONCLUSION: These results indicate that the analysis of the subcellular expression of survivin is a determining factor to define the prognostic value. Its evaluation, using a polyclonal antibody, might help clinicians in the stratification of patients with colorectal cancer.

Aged↗
PubMed2005

Pseudoxanthoma elasticum: a clinical, pathophysiological and genetic update including 11 novel ABCC6 mutations.

Pseudoxanthoma elasticum (PXE) is an inherited systemic disease of connective tissue primarily affecting the skin, retina, and cardiovascular system. It is characterised pathologically by elastic fibre mineralisation and fragmentation (so called "elastorrhexia"), and clinically by high heterogeneity in age of onset and the extent and severity of organ system involvement. PXE was recently associated with mutations in the ABCC6 (ATP binding cassette subtype C number 6) gene. At least one ABCC6 mutation is found in about 80% of patients. These mutations are identifiable in most of the 31 ABCC6 exons and consist of missense, nonsense, frameshift mutations, or large deletions. No correlation between the nature or location of the mutations and phenotype severity has yet been established. Recent findings support exclusive recessive inheritance. The proposed prevalence of PXE is 1/25,000, but this is probably an underestimate. ABCC6 encodes the protein ABCC6 (also known as MRP6), a member of the large ATP dependent transmembrane transporter family that is expressed predominantly in the liver and kidneys, and only to a lesser extent in tissues affected by PXE. The physiological substrates of ABCC6 remain to be determined, but the current hypothesis is that PXE should be considered to be a metabolic disease with undetermined circulating molecules interacting with the synthesis, turnover, or maintenance of elastic fibres.

Adenosine Triphosphate↗