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Purpose: Epidemiological evidence regarding the radiosensitivity of the lens of the eye and radiation cataract development has led to changes in the EU Basic Safety Standards for protection of the lens against ionizing radiation. However, mechanistic details of lens radiation response pathways and their significance for cataractogenesis remain unclear. Radiation-induced DNA damage and the potential impairment of repair pathways within the lens epithelium, a cell monolayer that covers the anterior hemisphere of the lens, are likely to be involved. Materials and Methods: In this work, the lens epithelium has been analyzed for its DNA double-strand break (DSB) repair response to ionizing radiation. The responses of epithelial cells located at the anterior pole (central region) have been compared to at the very periphery of the monolayer (germinative and transitional zones). Described here are the different responses in the two regions and across four strains (C57BL/6, 129S2, BALB/c and CBA/Ca) over a low dose (0–25 mGy) in-vivo whole body X-irradiation range up to 24 hours post exposure. Results: DNA damage and repair as visualized through 53BP1 staining was present across the lens epithelium, although repair kinetics appeared non-uniform. Epithelial cells in the central region have significantly more 53BP1 foci. The sensitivities of different mouse strains have also been compared. Conclusions: 129S2 and BALB/c showed higher levels of DNA damage, with BALB/c showing significantly less inter-individual variability and appearing to be a more robust model for future DNA damage and repair studies. As a result of this study, BALB/c was identified as a suitable radiosensitive lens strain to detect and quantify early low dose ionizing radiation DNA damage effects in the mouse eye lens specifically, as an indicator of cataract formation.

Differences between the crystal structures of inhibitor-bound and uninhibited forms of phosphofructokinase (PFK) from B. stearothermophilus have led to a structural model for allosteric inhibition by phosphoenolpyruvate (PEP) wherein a dimer-dimer interface within the tetrameric enzyme undergoes a quaternary shift. We have developed a labeling and hybridization technique to generate a tetramer with subunits simultaneously containing two different extrinsic fluorophores in known subunit orientations. This construct has been utilized in the examination of the effects of allosteric ligand and substrate binding on the subunit affinities of tetrameric PFK using several biophysical and spectroscopic techniques including 2-photon, dual-channel fluorescence correlation spectroscopy (FCS). We demonstrate that PEP-binding at the allosteric site is sufficient to reduce the affinity of the active site interface from beyond the limits of experimental detection to nanomolar affinity, while conversely strengthening the interface at which it is bound. The reduced interface affinity is specific to inhibitor binding because binding the activator ADP at the same allosteric site causes no reduction in subunit affinity. With inhibitor bound, the weakened subunit affinity has allowed the kinetics of dimer association to be elucidated.

Hydrostatic pressure is a useful tool in the study of varied fields such as protein aggregation, association, folding, ligand binding, and allostery. Application of pressure can have a significant effect on the p K a values of buffers commonly used for biochemical analysis. Consequently, cationic buffers, rather than neutral ones, are generally used to minimize pH effects; however, even with these buffers, the change in pH over 3 kbar may be consequential in highly pH-sensitive biochemical systems. Using fluorescence-based assays, we have systematically examined the effects of pressure on various buffers in the neutral pH range. We show that many commonly used cationic and Good’s buffers increase in pH with pressure on the order of 0.1 to 0.3 pH units/kbar, in agreement with other published values. Carboxylates and phosphate decrease in pH to a similar extent. Buffer mixtures, composed of both cationic and carboxylate or phosphate components, are shown to be an order of magnitude less pressure sensitive than the individual component buffers. Using various relative concentrations of Tris and either phosphate, tricarballylate (1,2,3-propanetricarboxylate), or CDA (1,1-cyclohexane diacetate) at pH values between 7 and 8 yields baroresistant buffer mixtures. Buffer mixtures can be optimized for a specific pH, and a list of mixtures is presented for general laboratory use.

The enzymatic degradation of recalcitrant plant biomass is one of the key industrial challenges of the 21st century. Accordingly, there is a continuing drive to discover new routes to promote polysaccharide degradation. Perhaps the most promising approach involves the application of “cellulase-enhancing factors,” such as those from the glycoside hydrolase (CAZy) GH61 family. Here we show that GH61 enzymes are a unique family of copper-dependent oxidases. We demonstrate that copper is needed for GH61 maximal activity and that the formation of cellodextrin and oxidized cellodextrin products by GH61 is enhanced in the presence of small molecule redox-active cofactors such as ascorbate and gallate. By using electron paramagnetic resonance spectroscopy and single-crystal X-ray diffraction, the active site of GH61 is revealed to contain a type II copper and, uniquely, a methylated histidine in the copper's coordination sphere, thus providing an innovative paradigm in bioinorganic enzymatic catalysis.

In 1959–1963 the prevalence of coal workers’ pneumoconiosis in the UK was 12%. By the end of 1997 it had fallen to 0.2%. Results for the 3 yr 1998–2000 show an increase to 0.8%.The most important causative factor is thought to be an increase in the average number of hours worked. The increased average age of miners and changes in mining practice may be contributory factors.

The early embryonic development and expression patterns of the eye lens specific cytoskeletal proteins, CP49 and CP95, were determined for the chick and were found to be similar in both human and mouse. These proteins, as well as their homologs in other species, are obligate polymerization partners which form unique filamentous structures termed "beaded filaments." CP49 and CP95 appeared as protein products after 3 days of embryonic development in the chick during the elongation of primary fiber cells. Although limited data were obtained for human embryos at these early developmental timepoints, they were consistent with the interpretation that the up-regulation of these lens specific proteins began only after the initiation of lens vesicle closure. In situ hybridization with the mouse lens confirmed that message levels for beaded filament proteins were greatly elevated in differentiating primary fiber cells. Nuclease protection assays established that mRNA levels for CP49 remained relatively constant while CP95 mRNA levels increased once the process of secondary fiber formation was under way. Although present in relatively low abundance, the mRNA for a unique splice variant of CP49, CP49(INS), was also detected early in embryonic development and into adulthood. Peptide-specific antibodies directed against unique predicted sequences were able to confirm the protein expression of CP49(INS) in both embryonic and adult chick lens cells. These data present the first detailed study of the expression of CP49 and CP95 during early lens development. They suggest that the up-regulated expression of CP49 and CP95 could serve as pan-specific markers for all vertebrate lens fiber development.

Over a 2-year period at our institution, 6 patients underwent metallic stent treatment, 5 for malignant conditions and 1 for a benign condition of the esophagus. The use of expandable metallic stents for benign strictures has paralleled malignant indications but is limited and less understood from a clinical standpoint. A review of current literature in the treatment of benign strictures is presented. Treatment of benign strictures is associated with high morbidity and mortality as demonstrated by the cumulative experience of 21 patients. Migration, hyperplastic tissue obstruction at the terminal ends, reflux, and complications of perforation occur at a prohibitive rate. We conclude that expandable metallic stents should be reserved for palliative treatment of esophageal malignant obstructions and tracheoesophageal fistulas. Pharmacological management, necessary dilatations and operative corrections (antireflux procedures, esophagectomy) are recommended treatments for benign strictures.

A new panel of anti-A-type lamin monoclonal antibodies was generated. Epitope mapping was performed by immunoblotting against GST-lamin fusion peptides. Epitopes were mapped to four different regions of human lamin A and three different regions of human lamin C. The distribution of A-type lamins was compared with the distribution of the proliferation marker Ki67 in proliferating and quiescent cultures of human dermal fibroblasts (HDFs) using a double indirect immunofluorescence assay. Antibodies that had been mapped to a region of the lamin C tail stained the nuclear envelope of proliferating and quiescent cells equally brightly. In contrast, antibodies recognizing epitopes in the head domain and rod domain of lamins A and C and the tail domain of lamin A stained the nuclear envelope of quiescent cells strongly but reacted poorly or not at all with the nuclear envelope of proliferating cells. Changes in the level of expression of lamins A and C were not detected in immunoblotting assays. However, epitope masking was revealed, and this occurred by two distinct mechanisms. Epitope masking in the head domain of lamins A and C occurred as a result of protein phosphorylation. Epitope masking in the rod domain of lamins A and C and in the tail domain of lamin A occurred through a physical association between the lamin and chromatin and/or other nuclear proteins. The cell cycle timing of epitope masking was investigated in HDFs that had been restimulated after serum starvation. Extensive epitope masking in restimulated cells only occurred after cells had passed through mitosis. These results are consistent with the hypothesis that rearrangement of A-type lamin filaments, as cells progress from a quiescent to a proliferating state, results in altered lamina associations.

Cell lines are the systems of choice to analyze cellular functions related to the particular organ system. For lens research, three cell lines are widely used: N/N1003A (derived from rabbit lenses), alpha TN4, and NKR-11 (both of murine origin). The aim of the current study was to characterize these particular cell lines with respect to their expression of genes that are considered to be lens specific or expressed preferentially in the lens, such as crystallins, Pax6, Filensin, CP49, MIP, and MP20.alpha A- and alpha B-crystallin cDNA from rabbit lenses were sequenced. The expression of various genes was analyzed by reverse transcription-polymerase chain reaction using specific primers and mRNA from three lens-derived cell lines. For control, the expression of the selected genes was compared in nonlenticular tissues of mouse as well as in non-lens-derived murine cell lines (EF43, NIH-3T3, and L929).None of the transcripts for beta B2-crystallin, gamma-crystallins, MIP, MP20, filensin, and CP49 could be detected in the lens-derived cell lines. Transcripts for alpha A-crystallin were amplified in alpha TN4, but not in N/N1003A and NKR-11 cells. Pax6, a master control gene of eye development, is expressed in all three lens-derived cell lines and, additionally, in cell lines of neuronal origin, but not in corneal endothelial cells and in the currently used control cell lines.Three cell lines of lenticular origin were tested for expression of genes that were found abundantly in the lens. The observed expression of Pax6 in all lens-derived cell lines allows their use in the analysis of corresponding signal chains.

The lens-specific intermediate filament (IF) proteins CP49 and filensin have been identified in a large number of evolutionary divergent species. In the chick lens both CP49 and filensin have been identified. Recently a unique variant of CP49, CP49ins has been identified. CP49ins contains an insertion of 49 amino acids in helix 1b giving it characteristics similar to the lamin-like cytoplasmic IF of invertebrates. The presence of this variant form in the chick lens poses some important questions about the co-assembly of the two CP49 forms and also the evolutionary relationship with invertebrate IF proteins.

The leaf-cutting antAcromyrmex octospinosus was shown to filter out into its infrabuccal pocket from liquid food, particles down to ten μ in diameter. The pocket acted as a receptacle for material licked from the ants' fungus garden and from their own bodies, and for leaf wax licked from leaves used for fungus culture. The infrabuccal pellets of worker ants, which might contain contaminating fungal spores, were always found away from the fungus garden and mostly on the refuse dump. Virgin queens however, regurgitated their pellets onto the fungus garden. Pellets regurgitated by worker ants were streaked onto agar plates, and from these the ant fungus was cultured. Worker ants were not able to start a new fungus garden, but the use of the infrabuccal pocket by queens to transmit the ant fungus to newly founded colonies can be seen as part of a general behaviour pattern.

Glossina morsitans morsitans Westw., Glossinidae, surviving 48 hr after topical doses of endosulfan which killed 15% during this period in an initial bioassay, were investigated for effects on their lipid reserves. Males dosed with endosulfan, or maintained in pairs after their third bloodmeal (12–15-day-old) had lower lipid reserves than solvent-treated controls throughout a period of starvation. Once-fed females treated similarly showed no differences. Dosed flies of both sexes accumulated lipid reserves over their first four meals more slowly than controls. It is suggested that the delay in accumulation of lipid reserves by both sexes following exposure to low doses of endosuifan, and the more rapid utilisation of these reserves by treated males, renders the flies more susceptible to death by starvation in the field. RESUME Effet de faibles doses d'endosulfan sur les reserves lipidiques de la mouche Tse Tse: Glossina morsitans morsitans. L'examen a porte sur les effets sur les reserves lipidiques des Glossina morsitans morsitans Westw. survivant 48 h, apres des applications locales d'endosulfan qui avaient tue 15% des mouches pendant cette ***periode au cours d'essais prealables. Des mâles traites avec de l'endosulfan, ou maintenus par paires apres leur troisieme repas de sang (âges de 12 a 15 jours) avaient moins de reserves lipidiques que les temoins traites avec un solvant pendant leur periode de jeune. Des femelles alimentees, une fois traitees de ta meme facon, ne presentaient pas de differences. Des mouches traitees, des deux sexes, ont accumule leurs reserves lipidiques apres leurs quatre premieurs repas plus lentement que les temoins. On peut supposer que le retard dans l'accumulation des reserves lipidiques des deux sexes apres une exposition a de faibles doses d'endosulfan, et l'utilisation plus rapide de ces reserves par les mâles traites, ont rendu les mouches plus susceptibles de mourir d'inanition dans la nature.

1. Laboratory ants preferred eating whole ant fungus staphylae to hyphae, and did not feed on other fungi. Homogenized ant fungus staphylae and hyphae were equally acceptable liquid food but other homogenized fungi were not drunk extensively. 2. Various arthropod fungjvores preferred to feed on ant fungus rather than any other fungus tested. Some preferred hyphae to staphylae, some vice versa and others had no preference. 3. The ants attacked animals on the nest and reduced the numbers of fungivores on the fungus garden. 4. The ant fungus grew best at 24.5°C and hardly at all at 10°C or 37°C. 5. The ants did not necessarily choose material which supported the best fungus growth in sterile culture and readily accepted substrates on which the fungus did not grow at all. No learning behaviour was noted. 6. The ant X fungus symbiosis is discussed as an example of co-evolution, a product of an evolutionary feedback. The ant is supplied with a highly nutritious, readily acceptable food source in return for complex fungus-culture behaviour, providing protection from fungivores and competition from other saprophytic fungi.

1. The workers and queen of the leaf-cutting ant Atta cephalotes fed on the juice of swollen hyphae (staphylae) produced by their cultivated fungus, but neither obtained sufficient energy from this source for their respiratory needs. The number of staphylae eaten by workers increased with worker size but was not enough to satisfy their energy requirements. 2. Larvae fed on whole staphylae and staphylae previously chewed by workers, and obtained sufficient energy from this source for respiration and growth. No evidence of feeding on fungus hyphae or of trophallaxis between worker and larvae was found. Larvae preferred staphylae to hyphae when fed them artificially and they gained more weight on the former. 3. Worker ants imbibed plant sap during the preparation of plant material for the fungus garden and the uptake of carbohydrate during this process was sufficient to supply their energy needs for approximately 24 h. 4. Staphylae were richer in lipid and carbohydrate, and poorer in protein than ant fungal hyphae. 5. The number of staphylae produced by the fungus gardens of two small nests was comparable with the observed consumption rate but would provide only about 4% of the nest's respiratory requirements. 6. In the light of these findings, a revised view of the role of the fungus in the diet of the ant is discussed.

In the laboratory, the trail pheromone methyl 4-methylpyrrole-2-carboxylate (M4MP2C) when added to bait particles acts as an attractant to leaf-cutting ants, increasing the pick-up of pheromone-impregnated bait compared with plain bait. However, field trials in Trinidad, Brazil and Paraguay were disappointing. Bait with and without pheromone was scattered in the foraging area, and the proportion of each taken to the nest by Atta sexdens rubropilosa Forel, A. cephalotes (L.) and Acromyrmex octospinosus (Reich) was assessed. In only one of the experiments (A. octospinosus foraging bait with 50 p.p.m. of M4MP2C) was increased pick-up detected. Four reasons for this are suggested: (1) small pheromone effects are difficult to measure as scattering bait produced a patchy distribution and heterogeneous replicates, whilst choice trials on plain and pheromone-impregnated bait placed close together were difficult to interpret, as the pheromone probably excited the ants, increasing pick-up of plain bait; (2) A. octospinosus workers, the subject of detailed studies, were less sensitive to M4MP2C in the field than in the laboratory; (3) as the pheromone only attracts, it does not produce a comparable increase in the number of pieces picked up, contact/pick-up ratios of sucroseimpregnated discs increasing from 2·26 at 5 pg pheromone to 16·39 at 50 ng; and (4) soyabean oil, citrus-pulp extract and orange juice were found to be attractive, and when pheromone was added, its effects were not additive. Early studies used sucrose-impregnated paper discs, and as these have no attractants of their own, the addition of M4MP2C had a more marked effect. It is concluded that M4MP2C is not a cost-effective addition to current leaf-cutting ant baits which possess food odours, a much cheaper source of attractiveness.

Relatively few cases of deletion 1q have been reported. These cases have been divided into three groups according to assigned breakpoints. They include proximal interstitial, intermediate interstitial, and terminal deletions. We present a male infant with an interstitial deletion of 1q with breakpoints determined by GTG banding as q25 and q32. Comparison with similar case reports suggests common physical features which include microcephaly, growth retardation, developmental delay, clinodactyly, and genital anomalies in affected males. However, no characteristic phenotypic appearance is definable. The infant also presented with prune belly sequence (PBS) with Potter facies. Fetal ascites, as noted in this case on prenatal ultrasound, appears to be an early factor in the pathogenesis of PBS. Therefore, detection of fetal ascites should suggest the presence of the PBS association and the need for more extensive prenatal evaluation.

Three perinatal health indicators (serum human placental lactogen [hPL] levels, serum free estriol [E3] levels, and OCT) were simultaneously completed in 149 high-risk women who were more than 34 weeks pregnant. There was a significant correlation between the hPL and E3 results (r = 0.28, p less than 0.01). There was a 15.4% positive OCT result rate and the blood hormone values for the negative and positive OCT groups were compared. There was a significantly lower hPL value in the positive OCT group (4.7 +/- S.E.M. 0.4 vs. 6.2 +/- S.E.M. 0.2 micrograms/ml for positive and negative groups, respectively), whereas the free E3 levels were not different in these two OCT groups (14.8 +/- S.E.M. 1.5 vs. 16.3 +/- S.E.M. 0.7 ng/ml for positive and negative groups, respectively). The free E3 value did not help in predicting the OCT result as the low free E3 subgroup had the same frequency of positive OCT result as did the over-all group. There was a highly significant increase in the positive OCT results (42.9%) in women with a low hPL value (p less than 0.01). In those women with an hPL value of 6.0 microgram/ml or more there were only 8% positive OCT's. It is concluded that on hPL test at about 34 weeks of gestation could be used to screen pregnant women, and if the value were low (less than 4.0 microgram/ml) an OCT evaluation test would be indicated, for there is a very high frequency of positive results in that subgroup of women.

The diagnosis of urinary-tract anomalies in the fetus can frequently be made with antenatal ultrasound imaging. This report details 19 cases of fetal urinary-tract malformation diagnosed during a 30-month period. Early onset and more complete urinary-tract obstruction, oligohydramnios, renal dysplasia, and pulmonary hypoplasia occur frequently in cases where urinary-tract anomalies were detected in utero. The frequent association of other major structural anomalies, severe renal damage, and irreversible pulmonary hypoplasia make imperative an intensive evaluation of the fetus before considering invasive surgical procedures.

The use of ultrasound in clinical obstetrics has provided a great opportunity to diagnose fetal developmental defects while the fetus is still in utero. Two cases of ours illustrate how an unusual sonographic artifact, fetal hair, can suggest abnormal fetal development.

Cytoplasmic retinoic acid binding protein (cRABP) is present in human fetal pancreas and becomes nondetectable in the normal adult pancreas. The binding protein for retinoic acid becomes apparent again in pancreatic cancer. Similar fluctuations in the content of cRABP occur in the hamster. The binding protein is undetectable in the normal adult hamster pancreas, while it was detected in several transplantable adenocarcinomas in the Syrian golden hamster.

Changes in placental texture and structure on ultrasonic examination have been suggested as correlating to advancing fetal pulmonary maturity. The association of preterm appearance of Grade III changes in the placenta in the complicated pregnancy suggests that these changes are associated with a decrease in placental function and premature senescence of the placenta. Placentas were routinely graded on all obstetric examinations performed during a 1-year period of time. Those pregnancies in which Grade III changes in the placenta prior to term were reviewed. A high incidence (78%) of perinatal problems were found in association with preterm appearance of Grade III changes. Perinatal complications included maternal hypertensive disorders, intrauterine growth retardation, abruptio placentae, and fetal distress in labor. The high incidence of these disorders in preterm pregnancies with Grade III changes in the placenta suggests that the sonographic changes found reflect placental dysfunction or senescence rather than normal maturational development. The appearance of Grade III changes in the placenta in the preterm pregnancy is suggested as a predictive indicator of potential perinatal problems in late pregnancy.

Placental grading has been proposed as a substitute for amniotic fluid analysis for predicting fetal pulmonary maturity. The efficacy of placental grading was prospectively evaluated by grading the placenta at the time of 174 amniocentesis procedures done for determination of fetal pulmonary maturity. Grade III changes in the placenta were a rare finding that occurred in only 7% of the examinations performed. Placental grading proved to be insensitive in that it predicted pulmonary maturity in only 5% of pregnancies in which amniotic fluid analysis predicted a mature fetus. In addition, placental grading falsely predicted fetal pulmonary maturity in 42% of patients in whom Grade III placental changes were found. These findings suggest that the determination of Grade III changes in the placenta occurs too rarely to be of use in predicting fetal pulmonary maturity in the uncomplicated pregnancy. Incorrect prediction of pulmonary maturity by placental grading in the complicated pregnancy makes this test of little value in the management of high-risk pregnancy.

The relationship between fetal femur length and biparietal diameter on ultrasound examination was evaluated in a large, unselected obstetric population of 12-40 weeks' gestational age. The derived ratio of fetal femur length to biparietal diameter was evaluated retrospectively as a tool for examining the technical reliability of fetal measurements obtained and as a screening mechanism for detecting asymmetric fetal development. The ratio of femur length to biparietal diameter is of value as an aid to the detection of fetal developmental anomalies and should be a routine parameter considered in the performance of an obstetric ultrasound examination.

Three primigravidas developed Rh sensitization after unexplained third-trimester fetal death. One patient manifested sensitization after the diagnosis of fetal death had been made but before delivery occurred. The other two demonstrated anti-D antibodies early in the next pregnancy, despite having received postpartum Rh immunoglobulin. Unsensitized Rh-negative women with unexplained third-trimester fetal death should be screened routinely for fetomaternal hemorrhage when fetal death is discovered, so that adequate prophylaxis against Rh sensitization can be given.

Ultrasonic determination of fetal femur length is useful as a parameter in the determination of fetal gestational age. One hundred thirty measurements were made in pregnancies at 14 to 36 weeks' gestation. The measurements were plotted against gestational age, and we found that a strong correlation exists between fetal femur length and fetal gestational age, with 95% confidence limits of plus or minus seven days. This ultrasound parameter of fetal age assessment should be added to the other methods available for accurate dating of pregnancy.

The first contribution to medical literature on the subject of dental dystrophies in congenital syphilis was that of Hutchinson, who described the upper central incisors in 1857. He depicted them as being peg-shaped and showing a cresentic notch on their incisal edge. He declared that this deformity was characteristic and was to be considered pathognomonic evidence of congenital syphilis. His views were vigorously contested by Parrot, who saw in them only evidence of rachitis, and by Magitot, who described a similar condition in the jaw of a cow, due to eclampsia. In 1884, Moon described the hypoplastic first molar, which he likewise attributed to congenital syphilis. In 1908, Cavallaro 1 of Florence, Italy, published an extensive article in Dental Cosmos , in which he purports to show that dentification of the first molar begins about the sixth month of fetal life and that of the incisor the first month after birth.