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PubMed2005

Neisseria meningitidis lactate permease is required for nasopharyngeal colonization.

Neisseria meningitidis is a human specific pathogen that is part of the normal nasopharyngeal flora. Little is known about the metabolic constraints on survival of the meningococcus during colonization of the upper airways. Here we show that glucose and lactate, both carbon energy sources for meningococcal growth, are present in millimolar concentrations within nasopharyngeal tissue. We used a mutant defective for the uptake of lactate (C311DeltalctP) to investigate the contribution of this energy source during colonization. Explants of nasopharyngeal tissue were inoculated with the wild-type strain (C311) and C311DeltalctP; the mutant was recovered at significantly lower levels (P = 0.01) than C311 18 h later. This defect was not due to changes in the expression of adhesins or initial adhesion in C311DeltalctP to epithelial cells. Instead, lactate appears to be important energy source for the bacterium during colonization and is necessary for growth of the bacterium in nasopharyngeal tissue. Studies with other strains defective for the uptake of specific nutrients should provide valuable information about the environment in which N. meningitidis persists during carriage.

Adhesins, Bacterial↗
PubMed2000

Characterizing and reporting pelvic floor defects: the revised New York classification system.

The authors have devised a conceptual model and reporting system for characterizing, grading and staging pelvic floor defects. The system is user friendly and simple to learn and apply. It is based on commonly known anatomic landmarks and can be performed without memorizing or referring to a separate characterization and reporting plan. Completing the accompanying forms is self-explanatory and provides the information needed for proper comprehension and recording of anatomic defects. The model and reporting format have been used at our institutions for 5 years by medical students, residents, fellows and attendings. It has several advantages over the Pelvic Organ Prolapse Quantitation (POPQ) system: (1) it uses known anatomic landmarks rather than alphabetic labels; (2) it grades lateral wall defects which the POPQ system omits; (3) it recognizes and reports isolated defects or tears which present as bulges in the vaginal walls without downward linear descent (prolapse); (4) it uses a one-page reporting form and a one-page checklist and vaginal profile; (5) it can be done easily in both the supine and the standing positions; (6) it requires simple instruments and a disposable measuring tape available in most office settings; (7) it includes urethral hypermobility in its reporting scheme; (8) it includes cervical length, perineal descent and other measurements in its reporting scheme; and (9) it is similar enough to the POPQ system that easy conversion to, and integration with, the POPQ reporting form and vaginal profile is possible. Prospective trials testing the validity of this system and comparing it with the POPQ system for validity, reliability, reproducibility, test-retest analysis, and interobserver and intraobserver variance are warranted.

Female↗
PubMed1970

Characteristics relevant to cardiovascular disease among adults of African and Indian origin in Guyana.

Characteristics relevant to cardiovascular disease, including anthropometry, arterial blood pressure, serum cholesterol levels, chest radiography and electrocardiography, were investigated in a survey of 843 men and women aged 35-54 years of African and Indian origin living in 2 communities in Guyana. Clinical experience suggested a high incidence of hypertension and a low incidence of ischaemic heart disease.Africans were taller and heavier than Indians but their other characteristics were, in general, similar except that their mean blood pressure levels and R amplitudes in certain ECG leads were consistently higher. Hypertension was common and was significantly correlated with obesity and, probably independently, with body size. Serum cholesterol levels, with mean values of about 200 mg/100 ml, were strongly correlated with factors associated with obesity in men but not in women. Cardiothoracic ratios, measured from chest films, were greater than values regarded as normal for Europeans because of a relative narrowness of thoracic diameters.Prevalence of S-T-segment and T-wave defects in ECGs classified by the Minnesota Code was as high as reported from communities where ischaemic heart disease is clinically more frequent. Hypertension, cardiac enlargement, obesity and cholesteraemia were more prevalent when defects involved lateral leads (I, aVL, V5 and V6) than in subjects with normal ECGs, suggesting that the majority of important abnormalities occurred primarily in the left ventricle and were probably related to hypertension rather than to coronary insufficiency without hypertension. Analysis of S-T and T-wave defects, both by blood pressure and by lead position, might show meaningful differences between populations which, by present methods of presentation, appear to have surprisingly similar prevalences of ECG abnormalities.

Adult↗
PubMed2006

[Conceptual reformulation of the double mesh repair technique: a simple solution for highly complex abdominal wall defects].

INTRODUCTION: Repair of complex abdominal wall defects remains a challenge for the general surgeon. The aim of the present study was to validate the double mesh repair technique in complex hernias. MATERIAL AND METHOD: We performed a prospective study of 15 patients with complex abdominal wall defects who underwent surgery in a university hospital. All patients were evaluated in a multidisciplinary unit. Indications consisted of incisional hernias with multiple recurrences (> 3 times), prior mesh complicated by fistula and chronic infection, giant diffuse lumbar hernia, and ventral hernia (associated with parastomal hernia or occurring after bariatric surgery with associated dermolipectomy). The surgical technique used was double intra-abdominal and supra-aponeurotic mesh repair without associated plasty techniques. Clinical, surgical and follow-up data were analyzed. RESULTS: Nine defects were lateral, three were lumbar, one was parapubic, and two were located in the mid-line (one associated with giant parastomal hernia and one occurring after bariatric surgery). Eight showed significant tissue loss, five showed trophic skin lesions, and two showed chronic suppurative infection. The mean size of the defects was 17.5 cm. Seroma occurred in three patients and limited cutaneous necrosis occurred in one patient. The mean length of hospital stay was 4.3 days (range 2-7 days). No complications, recurrences or mortality were detected during follow-up. CONCLUSION: Complex abdominal wall defects can be corrected through double repair using mesh only. This technique is simple to learn and perform and can be applied in many anatomical sites and types of defect, as well as in the presence of tissue destruction.

Abdominal Wall↗
PubMed2005

Computational modeling of the propagation of light through liquid crystals containing twist disclinations based on the finite-difference time-domain method.

The finite-difference time-domain (FDTD) method is used to compute propagation of light through textured uniaxial nematic-liquid crystal (NLC) films containing various types of twist disclination (defect) lines. Computational modeling by the FDTD method provides an accurate prediction of the optical response in multidimensional and multiscale heterogeneities in NLC films in which significant spatial optic axis gradients are present. The computations based on the FDTD method are compared with those of the classic Berreman matrix-type method. As expected, significant deviations between predictions from the two methods are observed near the twist disclination line defects because lateral optic axis gradients are ignored in the matrix Berreman method. It is shown that the failure of Berreman's method to take into account lateral optic axis gradient effects leads to significant deviations in optical output. In addition, it is shown that the FDTD method is able to distinguish clearly different types of twist disclination lines. The FDTD optical simulation method can be used for understanding fundamental relationships between optical response and complex NLC defect textures in new liquid-crystal applications including liquid-crystal-based biosensors and rheo-optical characterization of flowing liquid crystals.

Journal Article↗
PubMed1992

Method for identifying amblyopes whose reduced line acuity is caused by defective selection and/or control of gaze.

Three visual tests were administered to a group of 15 amblyopic children, 15 adult amblyopes and two age-matched control groups, each of 20 subjects. Test results comprised visual acuity for recognizing high contrast letters presented in line (i.e. Snellen) format, isolated-letter format and repeat-letter format. The classical Snellen format confounds the effects of gaze control defects with the effects of adjacent contours on a patient's ability to recognize a foveated letter. We designed a repeat-letter format intended to unconfound these effects. The repeat letter format is much less sensitive to gaze control defects, and somewhat more sensitive to adjacent contour interactions than is the Snellen format. We report that amblyopic eyes can be subdivided empirically into three repeat-letter categories: repeat-letter acuity significantly better than Snellen acuity; repeat letter acuity not significantly different from Snellen acuity; and repeat letter acuity significantly worse than Snellen acuity. We report that this subdivision cuts across the clinical subclassification of amblyopia and also across the crowding/no crowding subclassification. We suggest that, rather than abnormal lateral interactions, defective selection and/or control of gaze is an important factor in depressed visual acuity in amblyopic eyes of the first repeat-letter category but not for the third type, in which abnormal lateral interactions may be important. To test the hypothesis that the response to patching and refractive therapy may be less satisfactory in our first category of amblyopic eyes, we are carrying out a prospective study.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

CT analysis of pedicles and screw tracts after implant removal in thoracolumbar fractures.

Twenty-one burst fractures of the thoracolumbar junction were stabilized with a transpedicular fixator by surgeons experienced in this technique. Screws 5 or 6 mm in diameter were used. After the removal of the device 1 year postsurgery, axial CT scans were obtained of the instrumented vertebrae. Eighty-two pedicles were examined. In 16 pedicles, medial or lateral cortical defects were found. Five screws had intruded into the spinal canal by a maximum of 3.5 mm. In 48 pedicles a correlative comparison with the preoperative examinations was possible. Compared with the dimensions of the pedicles on the preoperative CT scans, 31 had increased in width, and 14 showed deformation indicative of fractures of the lateral pedicle wall. When the screw diameter exceeded 65% of the pedicles' outer diameter, 85% of the pedicles expanded. One of four screws had penetrated the anterior wall of the vertebra. Pedicle screw penetration on the left side above L2 poses potential risk of erosion of the aorta. The use of pedicle screws at the thoracolumbar junction by experienced surgeons carries some risk for malplacement and neurological damage. Mismatch between pedicle dimension and screw size results in pedicle expansion and lateral wall fractures, probably during screw insertion. Preoperative CT examinations should be used to help in choosing appropriate screw diameter presurgery.

Adult↗
PubMed2006

Novel hydroxyapatite/chitosan bilayered scaffold for osteochondral tissue-engineering applications: Scaffold design and its performance when seeded with goat bone marrow stromal cells.

Recent studies suggest that bone marrow stromal cells are a potential source of osteoblasts and chondrocytes and can be used to regenerate damaged tissues using a tissue-engineering (TE) approach. However, these strategies require the use of an appropriate scaffold architecture that can support the formation de novo of either bone and cartilage tissue, or both, as in the case of osteochondral defects. The later has been attracting a great deal of attention since it is considered a difficult goal to achieve. This work consisted on developing novel hydroxyapatite/chitosan (HA/CS) bilayered scaffold by combining a sintering and a freeze-drying technique, and aims to show the potential of such type of scaffolds for being used in TE of osteochondral defects. The developed HA/CS bilayered scaffolds were characterized by Fourier transform infra-red spectroscopy, X-ray diffraction analysis, micro-computed tomography, and scanning electron microscopy (SEM). Additionally, the mechanical properties of HA/CS bilayered scaffolds were assessed under compression. In vitro tests were also carried out, in order to study the water-uptake and weight loss profile of the HA/CS bilayered scaffolds. This was done by means of soaking the scaffolds into a phosphate buffered saline for 1 up to 30 days. The intrinsic cytotoxicity of the HA scaffolds and HA/CS bilayered scaffolds extract fluids was investigated by carrying out a cellular viability assay (MTS test) using Mouse fibroblastic-like cells. Results have shown that materials do not exert any cytotoxic effect. Complementarily, in vitro (phase I) cell culture studies were carried out to evaluate the capacity of HA and CS layers to separately, support the growth and differentiation of goat marrow stromal cells (GBMCs) into osteoblasts and chondrocytes, respectively. Cell adhesion and morphology were analysed by SEM while the cell viability and proliferation were assessed by MTS test and DNA quantification. The chondrogenic differentiation of GBMCs was evaluated measuring the glucosaminoglycans synthesis. Data showed that GBMCs were able to adhere, proliferate and osteogenic differentiation was evaluated by alkaline phosphatase activity and immunocytochemistry assays after 14 days in osteogenic medium and into chondrocytes after 21 days in culture with chondrogenic medium. The obtained results concerning the physicochemical and biological properties of the developed HA/CS bilayered scaffolds, show that these constructs exhibit great potential for their use in TE strategies leading to the formation of adequate tissue substitutes for the regeneration of osteochondral defects.

Animals↗
PubMed1977

Normal lid margin after eyelid reconstruction.

To prevent corneal damage, the central lid margin must have a normal skin-conjunctiva interface following the lid reconstruction. A two-step procedure may be employed: In the lower lid an initial Hughes reconstruction should be tried. If this is unacceptable, a subsequent block excision of the segment is performed. The important step in both phases is a thorough lateral cantholysis. In the upper lid, the central defect is immediately reconstructed by sliding the lateral lid remnant to the medial remnant. The resulting lateral defect is reconstructed with a Hughes procedure. In both cases, a physiologic lid margin is insured, because normal lid is sutured to normal lid.

Conjunctiva↗
PubMed1986

The lateral thoracodorsal flap in breast reconstruction.

A fasciocutaneous transposition flap, the lateral thoracodorsal flap, has been used in 114 cases of breast reconstruction. This flap is raised from the lateral and dorsal aspects of the thoracic wall at the level of the submammary crease, and the size may be varied from 12 to 22 cm in length and 6 to 12 cm in width. The lateral thoracodorsal flap is used with an implant and forms the lateral part of the reconstructed breast. A natural ptotic breast shape is achieved in a single-stage procedure. Complications such as partial necrosis and infection have occurred in 3.5 and 2.5 percent of cases, respectively. The procedure is simple and has at our unit largely replaced the use of the latissimus dorsi musculocutaneous flap in extensive postmastectomy defects. In less disfiguring defects, the lateral thoracodorsal flap has taken the place of direct implantation because the reconstructed breast obtains a more pleasing shape by augmentation of the lower lateral pole.

Adult↗
PubMed1983

Cavernous sinus syndrome due to prolactinoma: resolution with bromocriptine.

Cavernous sinus syndrome due to a pituitary tumor is quite rare. Our patient had a large prolacinoma that extended superiorly, causing bitemporal visual field defects, and laterally into the right cavernous sinus, causing tearing, dysesthesia in the distribution of the fifth cranial nerve, a loss of the corneal reflex, and a sixth cranial nerve palsy. Prolactin levels ranged between 800 and 1000 ng/mL. Treatment with 7.5 mg of bromocriptine daily caused a marked reduction in the size of the tumor and resolution of her visual field defects and cranial nerve dysfunction over 6 months. We feel that bromocriptine should be considered as initial therapy for patients with prolactinomas extending into the middle or posterior cranial fossae.

Bromocriptine↗
PubMed1995

Expression of the acetylcholinesterase transcript in the chordotonal neurons of Drosophila embryos.

The transcript of the acetylcholinesterase gene (Ace) was detected in the central nervous system (CNS) and the lateral chordotonal neurons (lch3, lch5) of wild type Drosophila melanogaster embryos. Ace126, a representative mutation of the acetylcholinesterase gene, abolished expression in the lch3 and lch5 neurons and slightly reduced the number of lch5 cells in some abdominal segments. The number of lch5 neurons was also reduced in Ace hemizygous and transheterozygous mutant embryos. The correlation between the lack of Ace expression and the mild defect of lateral chordotonal neurons is discussed.

Acetylcholinesterase↗
PubMed2006

Blind homologous R2R3 Myb genes control the pattern of lateral meristem initiation in Arabidopsis.

In seed plants, shoot branching is initiated during postembryonic development by the formation of secondary meristems. These new meristems, which are established between the stem and leaf primordia, develop into vegetative branches or flowers. Thus, the number of axillary meristems has a major impact on plant architecture and reproductive success. This study describes the genetic control of axillary meristem formation in Arabidopsis thaliana by a group of three R2R3 Myb genes, which are homologous to the tomato (Solanum lycopersicum) Blind gene and were designated REGULATORS OF AXILLARY MERISTEMS (RAX). rax mutants show new phenotypes that are characterized by defects in lateral bud formation in overlapping zones along the shoot axis. RAX genes are partially redundant in function and allow a fine-tuning of secondary axis formation. As revealed by monitoring of SHOOT MERISTEMLESS transcript accumulation, the RAX genes control a very early step of axillary meristem initiation. The RAX1 and RAX3 expression domains specifically mark a cell group in the center of the leaf axil from which the axillary meristem develops. Double mutant combinations of lateral suppressor and rax1-3 as well as expression studies suggest that at least two pathways control the initiation of axillary meristems in Arabidopsis.

Arabidopsis↗
PubMed2003

Pitx2c attenuation results in cardiac defects and abnormalities of intestinal orientation in developing Xenopus laevis.

The experimental manipulation of early embryologic events, resulting in the misexpression of the homeobox transcription factor pitx2, is associated with subsequent defects of laterality in a number of vertebrate systems. To clarify the role of one pitx2 isoform, pitx2c, in determining the left-right axis of amphibian embryos, we examined the heart and gut morphology of Xenopus laevis embryos after attenuating pitx2c mRNA levels using chemically modified antisense oligonucleotides. We demonstrate that the partial depletion of pitx2c mRNA in these embryos results in alteration of both cardiac morphology and intestinal coiling. The most common cardiac abnormality seen was a failure of rightward migration of the outflow tract, while the most common intestinal laterality phenotype seen was a full reversal in the direction of coiling, each present in 23% of embryos injected with the pitx2c antisense oligonucleotide. An abnormality in either the heart or gut further predisposed to a malformation in the other. In addition, a number of other cardiac anomalies were observed after pitx2c mRNA attenuation, including abnormalities of atrial septation, extracellular matrix restriction, relative atrial-ventricular chamber positioning, and restriction of ventricular development. Many of these findings correlate with cardiac defects previously reported in pitx2 null and hypomorphic mice, but can now be assigned specifically to attenuation of the pitx2c isoform in Xenopus.

Animals↗
PubMed1984

Temporalis pericranial muscle flap for reconstruction of the lateral face and head.

Large ablative surgical tissue defects of the lateral face and head can pose a difficult task for the reconstructive surgeon who must choose from among a large variety of possible reparative techniques. In many situations the temporalis pericranial muscle flap offers the outstanding feature of providing a large amount of soft tissue at no direct expense of donor site skin cover. It is easily obtained and results in negligible functional loss. With care taken to preserve the neurovascular pedicle, this flap may be rotated in multiple directions and even overturned as either surface can receive surface skin closure. The amount of operative time and effort required is much less than for many of the more elaborate reconstructive flaps. Five representative cases are presented.

Adult↗
PubMed2005

Fibrinogen Philadelphia, a hypodysfibrinogenemia characterized by abnormal polymerization and fibrinogen hypercatabolism due to gamma S378P mutation.

Fibrinogen Philadelphia, a hypodysfibrinogenemia described in a family with a history of bleeding, is characterized by prolonged thrombin time, abnormal fibrin polymerization, and increased catabolism of the abnormal fibrinogen. Turbidity studies of polymerization of purified fibrinogen under different ionic conditions reveal a reduced lag period and lower final turbidity, indicating more rapid initial polymerization and impaired lateral aggregation. Consistent with this, scanning and transmission electron microscopy show fibers with substantially lower average fiber diameters. DNA sequence analysis of the fibrinogen genes A, B, and G revealed a T>C transition in exon 9 resulting in a serine-to-proline substitution near the gamma chain C-terminus (S378P). The S378P mutation is associated with fibrinogen Philadelphia in this kindred and was not found in 10 controls. This region of the gamma chain is involved in fibrin polymerization, supporting this as the polymerization defect causing the mutation. Thus, this abnormal fibrinogen is characterized by 2 unique features: (1) abnormal polymerization probably due to a major defect in lateral aggregation and (2) hypercatabolism of the mutant protein. The location, nature, and unusual characteristics of this mutation may add to our understanding of fibrinogen protein interactions necessary for normal catabolism and fibrin formation.

Afibrinogenemia↗
PubMed2001

Identification of connexin43 (alpha1) gap junction gene mutations in patients with hypoplastic left heart syndrome by denaturing gradient gel electrophoresis (DGGE).

Gap junction channels formed by the connexin43 protein are considered to play crucial roles in development and function because they allow the direct cell-to-cell exchange of molecules that mediate multiple signaling events. Previous results have shown that connexin43 channels are intricately gated by phosphorylation and that disruption of this regulation gives rise to severe heart malformations and defects of laterality in human, chick and frog. Here we report the identification of connexin43 gene mutations that represent a minor population of connexin43 alleles, which could be reliably detected by using denaturing gradient gel electrophoresis (DGGE) to visualize normal and mutant DNAs that were separately sequenced. In contrast, sequencing of total PCR products without DGGE-pre-selection failed to consistently identify these mutations. Forty-six controls and 20 heart transplant recipients were examined in this study. In the latter group, 14 children had hypoplastic left heart syndrome (HLHS) in which connexin43 gene defects were detected in eight. The remaining six transplant patients with HLHS and all controls showed no defects. All eight HLHS children with gene defects had the same four substitutions: two that were silent polymorphisms, and two that were missense, replacing arginine codons at positions 362 and 376 with codons for glutamines. All four of these substitutions are identical to the nucleotide sequence of the connexin43 pseudogene, suggesting the possibility of an illicit recombination. A breakpoint region was identified 5' to the mutation site in a 63bp domain that is 100% identical in the gene and pseudogene. Results from in vitro phosphorylation indicate that the absence of arginines 362 and 376 completely abolishes phosphorylation in the connexin43 channel regulation domain suggesting a possible mechanism for the pathologies associated with HLHS.

Base Sequence↗
PubMed2002

Forearm bone non-union and its management.

A total of 125 patients with forearm (radio-ulnar) bone compound fractures resulting from missile injuries were examined 8 to 16 weeks after the time of injury with the objective of finding out the rate and causes of non-union. Initial management in each case was circular POP with windows for wound care or posterior slabs made of POP, Cramer-wire, or wood at random. Out of these, 22 (17.5%) patients had non-union. All were male, mean age 26 years, in good nutritional state and no underlying chronic illnesses found on routine examination. Fourteen had ulnar bone and 8 radial bone non-union. Four of the patients with ulnar non-union had both radio-ulnar fracture. All 22 patients had haematocrit values > 30%, had no associated injury and none had vascular injury at site of wounding. Seven (32%) had wound infection. All wounds healed within 2-4 weeks after injury. Diagnosis of non-union was made by clinical examination and x-rays of the forearm. All the 22 cases were operated on under general anaesthesia and exploration revealed that 18 had bone defects ranging from 1 cm to 5 cm, 2 had soft tissue interposition and 2 had failure of reduction as the obvious cause of non-union. Cancellous, slivered iliac bone grafts were made in all cases to bridge gaps and induce osteogenesis. Stabilization was made by rush-pins used as intramedullary nails in 12 cases in addition to either long or short arm plaster of paris casts in all cases. There was no post-operative infection including the donor site and all had well healed wounds and good union 8-10 weeks later. Bone defect is the most common cause of non-union of forearm bone fractures resulting from missile injury and early slivered cancellous bone graft is effective in the treatment of non-union.

Adult↗