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Biomedical subjects

J Jan

Publications and source records attributed to J Jan.

At least 19 recordsLinked to original sources
PubMed2005

Argon laser photocoagulation for retinopathy of prematurity: long-term outcome.

PURPOSE: To assess the visual, refractive, ocular structural, and neurodevelopmental outcome in a group of children who were screened, treated with laser photocoagulation for threshold retinopathy of prematurity (ROP), and followed up at our institution. METHODS: The 21 survivors of a cohort of 23 children were recalled at the age of 5 years or more. They underwent a full ophthalmologic examination. A paediatric neurologist and/or developmental paediatrician performed a neurodevelopmental assessment and a neuropsychologist performed psychological testing. RESULTS: A total of 30 eyes (71.4%) had a best-corrected visual acuity (BCVA) of 20/40 or better. In all, 26 (62%) eyes were myopic; the overall mean spherical equivalent was -4.95 D. No eye had Stage 4 findings and only one eye (2.4%) progressed to stage 5 despite photocoagulation. In total, 14 patients (66.6%) showed evidence of stereopsis. Strabismus was seen in six patients (28.5%) and nystagmus in three (14.3%). Periventricular leukomalacia (PVL) was identified in five patients (23.8%), cerebral palsy (CP) in seven (33.3%), and intraventricular haemorrhage (IVH) in 13 (62%). Cerebral palsy and IVH associated strongly with visual acuity of less than 20/40 (P=0.009 and 0.047). There was also a strong association between visual acuity of 20/40 or above and a better cognitive outcome (P=0.013). CONCLUSIONS: Retinal scarring and detachment are relatively rare causes of visual morbidity 5 years or more after laser treatment for threshold ROP, but the neurological sequelae of extreme prematurity and amblyopia remain important causes of impaired visual function.

Amblyopia↗
PubMed2004

Loss of heterozygosity and immunohistochemistry of adenocarcinomas of the esophagus and gastric cardia.

PURPOSE: Adenocarcinomas of the distal esophagus and gastric cardia are two tumors that have many features in common. They have similar prognoses, treatment modalities, and patterns of dissemination. The etiology is different, with gastroesophageal reflux disease playing a major role for esophageal adenocarcinoma, in contrast to adenocarcinoma of the gastric cardia. In the present study, we investigated several genetic and immunohistochemical features of adenocarcinomas of the distal esophagus and gastric cardia. EXPERIMENTAL DESIGN: Sixty-two resection specimens of either adenocarcinoma of the esophagus or adenocarcinoma of the gastric cardia were carefully selected. The genetic analysis included loss of heterozygosity of several tumor suppressor genes known to be involved in esophagogastric carcinogenesis. Immunohistochemical studies included the analysis of p53, c-Met, c-erbB-2, beta-catenin, and cyclooxygenase-2. In addition, a mutation analysis of the Tcf1 gene was done by direct sequencing. RESULTS: Patients with cardiac carcinoma had a significantly worse tumor stage and poorer differentiation on histology. Loss of heterozygosity analysis did not reveal significant differences between esophageal adenocarcinoma and cardiac adenocarcinoma. Immunohistochemical analysis revealed significantly more nuclear accumulation of beta-catenin and overexpression of cyclooxygenase-2 in patients with esophageal adenocarcinoma, compared with patients with cardiac carcinoma. No mutation was found in the Tcf1 gene in either tumor type. CONCLUSIONS: Although adenocarcinomas of the distal esophagus and gastric cardia have many features in common, we have found some evidence that they might form two different entities.

Adenocarcinoma↗
PubMed2004

Multimodal retinal image registration for optic disk segmentation.

OBJECTIVES: The analysis of the optic disk morphology with the means of the scanning laser tomography is an important step for glaucoma diagnosis. A method we developed for optic disk segmentation in images of the scanning laser tomograph is limited by noise, non-uniform illumination and presence of blood vessels. Inspired by recent medical research, we wanted to develop a tool for improving optic disk segmentation by registration of images of the scanning laser tomograph and color fundus photographs and by applying a method we developed for optic disk segmentation in color fundus photographs. METHODS: The segmentation of the optic disk for glaucoma diagnosis in images of the scanning laser tomograph is based on morphological operations, detection of anatomical structures and active contours and has been described in a previous paper. The segmentation of the optic disk in the fundus photographs is based on nonlinear filtering, Canny edge detector and a modified Hough transform. The registration is based on mutual information using simulated annealing for finding maxima. RESULTS: The registration was successful 86.8% of the time when tested on 174 images. Results of the registration have shown a very low displacement error of a maximum of about 5 pixels. The correctness of the registration was manually evaluated by measuring distances between the real vessel borders and those from the registered image. CONCLUSIONS: We have developed a method for the registration of images of the scanning laser tomograph and fundus photographs. Our first experiments showed that the optic disk segmentation could be improved by fused information from both image modalities.

Fundus Oculi↗
PubMed2001

Construction of protein overproducer strains in Bacillus subtilis by an integrative approach.

We evaluated the effect of several genetic factors reported as having a role in the induction of the expression of significant levels of recombinant protein in Bacillus subtilis. We utilized the beta-galactosidase reporter protein from Escherichia coli as our model for measuring the overproduction of heterologous proteins in B. subtilis. The lacZ gene was expressed in B. subtilis using the regulatory region of the subtilisin gene aprE. In this study, we considered factors known to modulate the transcription and translation initiation rates and genetic and mRNA stability. We also consider the effects of different genetic backgrounds, such as degU32 and hpr2, that until now have been studied independently. By changing the native -35 promoter box to the consensus TTGACA sequence of the aprE promoter, a significant 100-fold increase in the beta-galactosidase activity was obtained. On the other hand, changes such as the GTG to ATG start codon, the construction of a consensus AAGGAGG ribosome binding site, and the addition of the cryIIIA transcription terminator at the 3' end of the lacZ gene, produced only marginal effects on the final beta-galactosidase activity.

Bacillus subtilis↗
PubMed2001

Bioconcentration of lipophilic organochlorines in ovine dentine.

The bioconcentration of lipophilic organochlorines in ovine dentine in comparison to adipose tissue was examined. Sheep were given a single dose (0.2-1.4 mg/kg body wt) of individual polychlorobiphenyl (PCB) congeners (tetrachlorobiphenyls IUPAC Nos. 54 and 80, and hexachlorobiphenyls IUPAC Nos. 155 and 169) and organochlorine pesticides 1,1-bis(4-chlorophenyl)-2,2-dichloroethene) (4,4'-DDE) and hexachlorobenzene (HCB). They were killed 2 months after the dose and teeth and adipose tissue were collected. For the extraction of organochlorines, dentine was treated ultrasonically with sulfuric acid and hexane. The concentration of organochlorines in dentine and adipose tissue was determined by high-resolution gas chromatography with electron-capture detection. The bioconcentration of 'planar' compounds (PCB-169, HCB) in dentine, compared to adipose tissue, was lower than that of 'non-planar' (PCB-155, 4,4'-DDE). Ratios of the non-planar to planar compounds PCB-155/-169 and 4,4'-DDE/HCB in dentine were 1.4 and 7.2, and in adipose tissue 0.5 and 2.4, respectively. The dentine:adipose tissue bioconcentration ratios (on a lipid basis) of PCB-54, -80, -155, -169, 4,4'-DDE and HCB were 47, 16, 0.3, 0.1, 3.2 and 1.0, respectively. The results indicate that the bioconcentration of organochlorines in different tissues cannot be based on lipid content only. It is suggested that the physicochemical properties of individual organochlorines, i.e. lipophilicity (K(ow)), diffusivity, metabolism and tissue-specific interactions, play a part in the different bioconcentrations of individual organochlorine pollutants in dentine compared to adipose tissue.

Adipose Tissue↗
PubMed2001

Preventing drug interactions by online prescription screening in community pharmacies and medical practices.

BACKGROUND: Drug interactions have been shown to be preventable by computerized prescription entry and screening only in hospitals and not in community-based practice. METHODS: We retrospectively evaluated the effect of online prescription screening in community pharmacies and physician offices of one health maintenance organization, phased in during 3 consecutive 6-month periods in 1998 to 1999 (period I, system active only in 40% of pharmacies; period II, system active in 90% of pharmacies and 50% of physician offices; period III, system active in 95% of pharmacies and 90% of physician practices), on rates of prescriptions with-, patient exposure to-, and physician prescribing of-potential drug interactions. FINDINGS: Cumulative data included 775,186 patients given at least one prescription, by one or more of 5504 physicians, whose prescriptions were dispensed at 572 pharmacies. Dispensing of drug interaction prescriptions was reduced by 21.1% and by 67.5% in periods II and III compared with period I (odds ratio, 0.79; 95% confidence limit, 0.75-0.83 and odds ratio, 0.28; 95% confidence limit, 0.26-0.30, respectively). Patient exposure decreased only in those receiving 3 to 7 concurrent drugs (odds ratio, 0.80; 95% confidence limit, 0.71-0.90) with no reductions for patients who were given 2 drugs or 8 or more drugs. Only 19% to 25% of physicians wrote prescriptions for drugs that interact, but 85% of these repeated this pattern after being alerted. The proportion of prescriptions of drugs that interact that originated with a single prescriber, as opposed to 2 prescribers, decreased during the 3 periods from 0.81 to 0.74 and 0.69 (P <.001). INTERPRETATION: Computerized prescription entry and drug interaction screening in the community caused a 62.8% reduction in pharmacy-dispensed prescriptions with severe drug interactions and a 20% reduction in patient exposure to prescriptions with severe drug interactions; this reduction was negated by polypharmacy of 8 or more drugs. The effect of interaction alerts on physician prescribing patterns was limited.

Adult↗
PubMed2000

Characterization of the 5' subtilisin (aprE) regulatory region from Bacillus subtilis.

The aprE gene of Bacillus subtilis encodes the major serine alkaline protease known as subtilisin. It is expressed during the transition state and transcribed by the sigma(A) form of the RNA polymerase (RNAP). In this work, we characterized the regulatory region of the aprE gene (rraprE) from B. subtilis. By computer analysis and site-directed mutagenesis, we localized the aprE promoter sequence 7 bp upstream from its transcription initiation site (TIS). We also characterized the static curvature properties of the rraprE DNA and found two different areas of DNA bending, within the first 400 bp upstream of its TIS. We postulate that these particular curved DNA regions could play a role in the interaction with some regulatory proteins and discuss possible implications related to aprE transcription regulation.

Bacillus subtilis↗
PubMed2000

Mutation analysis of 3 genes in patients with Leber congenital amaurosis.

OBJECTIVE: To assess the frequency of mutations in the CRX, GUCY2D, and RPE65 genes in patients with Leber congenital amaurosis (LCA). PATIENTS: One hundred seventy-six probands with a clinical diagnosis of LCA were from 9 countries, with the largest subgroup being 39 probands from India. METHODS: Samples were screened with single-strand conformation polymorphism analysis followed by DNA sequencing of 3 genes (CRX, GUCY2D, and RPE65) known to be associated with LCA. RESULTS: Of the 176 probands, 28 (15.9%) harbored possible disease-causing mutations. The relative contribution of each gene to the total number of mutations was as follows: CRX, 2.8%; GUCY2D, 6.3%; and RPE65, 6.8%. No patients who harbored mutations in these genes had associated systemic abnormalities. Molecular diagnosis allowed definitive genetic counseling in a family affected with Best disease and LCA. CONCLUSIONS: Molecular diagnosis may be of benefit to patients affected with LCA. The relative paucity of mutations found in this study suggests that more LCA-associated genes remain to be discovered. CLINICAL RELEVANCE: Molecular diagnosis can confirm and clarify the diagnosis of LCA. As genotype data accumulate, clinical phenotypes associated with specific mutations will be established. This will facilitate the counseling of patients on their visual prognosis and the likelihood of associated systemic anomalies.

Adolescent↗
PubMed1999

Tissue distribution of planar and non-planar chlorobiphenyls, 4,4'-DDE and hexachlorobenzene in sheep and lambs.

The bioconcentration and distribution pattern of individual PCB congeners (IUPAC Nos: -54, -80, -155 and -169) and organochlorine pesticides (HCB and 4,4'-DDE) in blood, adipose tissue, liver and brain were examined in sheep two months after administration and in their offspring continuously exposed during the two months lactation period. Analyses were performed by high resolution gas chromatography. The levels of individual organochlorines varied significantly between tissues; the tissue/blood ratio (on a fat basis) varied by two orders of magnitude for individual congeners. The bioconcentration of the toxic planar PCB-169 congener was the highest in the liver and the lowest in the brain of the sheep.

Adipose Tissue↗
PubMed1998

Blood lactate concentrations during exercise: effect of sampling site and exercise mode.

BACKGROUND: The purpose of the study was to compare blood lactate concentrations determined in blood sampled from three sites (finger capillary, ear-lobe capillary, and forearm vein) during exercise on three different ergometers (a cycle ergometer, a treadmill and an arm-crank ergometer). METHODS: A total of 312 well-trained subjects performed either a six-minute steady-state exercise (n = 219) or an incremental exercise test until exhaustion (n = 93). Blood was sampled from two sites after each exercise test and at the end of each stage of the incremental protocol, 852 pairs of blood samples were analysed. RESULTS: Results showed that, when exercise was performed on a cycle ergometer or a treadmill, no significant differences between venous and ear capillary samples were observed whereas finger capillary values were higher. On an arm-crank ergometer, venous and finger capillary lactate concentrations were usually higher than ear capillary values with some discrepancies depending on the times of sampling. CONCLUSIONS: We conclude that lactate values may differ depending on the sampling site and the type of exercise mode. An ear capillary sample may be preferred because it is less affected by lactate release in the arms and easier to obtain.

Adolescent↗
PubMed1996

Transfer of planar and non-planar chlorobiphenyls, 4,4'-DDE and hexachlorobenzene from blood to milk and to suckling infants.

The transfer coefficients of tetra- and hexachlorobiphenyls (PCB-54; -80; -155; and -169), HCB and 4,4'-DDE between milk and blood were monitored for eight weeks in sheep previously administered with these compounds by intramuscular injection. Analyses were performed by high resolution gas chromatography. The milk/blood ratio on a fat basis was close to 1 for HCB, over 1 for 4,4'-DDE, PCB-155, and -169 and below 1 for PCB-54 and -80. It is speculated that the deviation from the ratio 1 results from the interactions of organochlorines with (lipo)proteins in blood and/or milk. In milk, the enrichment of 4,4'-DDE, PCB-155 and -169 was observed. The relative toxicity expressed by the toxic equivalent (on a fat basis) was approximately 2.5 times higher in milk than in blood.

Animals↗
PubMed1996

Gender effect on the relationship of time limit at 100% VO2max with other bioenergetic characteristics.

The aim of this study was to investigate the influence of gender on the possible contribution of tlim at Va max (minimal speed that elicits VO2max) in performance speeds. The male and female elite middle-distance runners had similar performance (IAAF scores). Fourteen female and fifteen male (25.2 +/- 3.6 and 25.1 +/- 4.2 yr old; VO2max = 63.2 +/- 4.2 and 77.7 +/- 6.4 ml.kg-1 min-1; Va max = 17.3 +/- 0.7 and 20.8 +/- 1.1 km.h-1, respectively) performed three exercise tests on a treadmill (3 degrees slope) within a 2-wk period: an incremental test to determine VO2max, Va max and the velocity at the onset of blood lactate accumulation (VOBLA); an exhaustive constant velocity test to determine tlim at Va max; and an exhaustive constant velocity test at 110% Va max to determine the accumulated oxygen deficit (AOD). There were no effects of gender, i.e., no significant differences were observed between female and male for tlim at Va max (421 +/- 129 vs 367 +/- 118 s respectively; P = 0.24), VOBLA as % Va max (88.4 +/- 2.7 vs 90.4 3% of Va max; P = 0.07), AOD (40.1 +/- 14.9 vs 48.9 +/- 21.3 ml.O2.kg-1; P = 0.22), running economy at the same absolute speed, i.e., 14 km.h-1 (53.4 +/- 2.6 vs 52.7 +/- 4.1 ml.O2.min-1.kg-1; P = 0.64) nor for gross oxygen cost of running (CR) at the same relative velocity (75% Va max) (0.214 +/- 0.001 vs 0.214 +/- 0.002 ml.O2.kg-1.m-1; P = 0.94). However, an effect of gender was found on the relationship between the bioenergetic parameters and performance. For male, v1500 was predicted by Va max, VOBLA, tlim at 110% of Va max, and CR (R2 = 0.96). For female, no bioenergetic parameters were strongly correlated with v1500 m. The inverse relationship found between Va max and tlim at Va max in previous literature was confirmed by the 29 runners in this study and for the subset of male only.

Adult↗
PubMed1991

[A case of small cell carcinoma originating at the site of pneumoplication of giant bulla five years later].

A 64 year-old man was performed pneumoplication for his left-sided giant bulla on December 15, 1983. After five years, consciousness loss and right hemiplegia occurred. Brain CT revealed a cystic lesion with enhancement in the left occipital lobe. Brain biopsy disclosed metastatic small cell carcinoma. Lung biopsy showed the same histopathology, so primary lesion was considered to be from the site of the previous pneumoplication. Lung cancer associated with emphysematous bulla have been mostly characterized by tumor shadow or niveáu in the bulla. In this case, the postoperative infiltrating shadow of pneumoplication had made early diagnosis difficult.

Carcinoma, Small Cell↗
PubMed1988

Isokinetic investigation of knee extensors and knee flexors in young French soccer players.

The knee extensor and knee flexor muscle groups in three groups of young soccer players were tested with a Cybex II isokinetic dynamometer and compared with adults. Muscle strength increased with age. The largest gain was observed in young players aged 16-17 years whose quadriceps was the most modified muscle group giving the lowest H/Q ratio. Analysis of the regression equations obtained for torque values at 30 degrees s-1 and 180 degrees s-1 revealed that there were two distinct groups: under 16 and over 16. After reaching 16 years of age, the increase in muscle strength is greater at low velocity than at high velocity.

Adolescent↗