The prediction of candidate genes for cervix related cancer through gene ontology and graph theoretical approach

With rapidly changing technology, prediction of candidate genes has become an indispensable task in recent years mainly in the field of biological research. The empirical methods for candidate gene prioritization that succors to explore the potential pathway between genetic determinants and complex diseases are highly cumbersome and labor intensive. In such a scenario predicting potential targets for a disease state through in silico approaches are of researcher's interest. The prodigious availability of protein interaction data coupled with gene annotation renders an ease in the accurate determination of disease specific candidate genes. In our work we have prioritized the cervix related cancer candidate genes by employing Csaba Ortutay and his co-workers approach of identifying the candidate genes through graph theoretical centrality measures and gene ontology. With the advantage of the human protein interaction data, cervical cancer gene sets and the ontological terms, we were able to predict 15 novel candidates for cervical carcinogenesis. The disease relevance of the anticipated candidate genes was corroborated through a literature survey. Also the presence of the drugs for these candidates was detected through Therapeutic Target Database (TTD) and DrugMap Central (DMC) which affirms that they may be endowed as potential drug targets for cervical cancer.

Identification of synthetic lethal pairs in biological systems through network information centrality

The immense availability of protein interaction data, provided with an abstract network approach is valuable for the improved interpretation of biological processes and protein functions globally. The connectivity of a protein and its structure are related to its functional properties. Highly connected proteins are often functionally cardinal and the knockout of such proteins leads to lethality. In this paper, we propose a new approach based on graph information centrality measures to identify the synthetic lethal pairs in biological systems. To illustrate the efficacy of our approach, we have applied it to a human cancer protein interaction network. It is found that the lethal pairs obtained were analogous to the experimental and computational inferences, implying that our approach can serve as a surrogate for predicting the synthetic lethality.

Observations on the Foliar Nematode, Aphelenchoides besseyi, Infecting Tuberose and Rice in India

The foliar nematode Aphelenchoides besseyi causes white tip disease in rice (Oryza sativa L.) and floral malady in tuberose (Polianthes tuberosa L.). This nematode is widely distributed in the rice fields of many states of India, including West Bengal (WB), Andhra Pradesh (AP), Madhya Pradesh (MP) and Gujarat (GT). In order to generate information on intraspecific variations of A. besseyi as well as to confirm the identity of the nematode species infecting these important crops, morphological observation was undertaken of A. besseyi isolated from tuberose and rice from WB and rice from AP, MP and GT. The molecular study was only done for rice and tuberose populations from AP and WB. The variations were observed among the populations in the tail, esophageal and anterior regions, including the occurrence of four as well as six lateral lines in the lateral fields. The morphometrics of observed populations showed variations and those could be regarded as a consequence of host-induced or geographical variations. PCR amplification of the rDNA ITS 1 and 2 region of rice (AP) and tuberose (WB) populations of A. besseyi generated one fragment of approximately 830 bp, and the size of the ITS region was 788 bp and 791 bp for tuberose and rice population, respectively. Alignment of the two sequences showed almost 100% similarity. Blast analysis revealed a very high level of similarity of both the Indian strains to a Russian population. The Indian and Russian strains could be differentiated using restriction enzyme Bccl. Host tests revealed that rice (cv. IET 4094), oat (cv. OS-6) and teosinte (cv. TL-1) showed a typical distortion due to the infection of A. besseyi. Five germplasm lines of oat showed no infection of the nematode under field conditions. Local cultivars of onion, maize, chrysanthemum, gladiolus, and Sorghum halepense were also not infected by A. besseyi.

The TBX21 transcription factor T-1993C polymorphism is associated with decreased IFN-γ and IL-4 production by primary human lymphocytes

T-bet is a transcription factor that drives the Th1 immune response primarily through promoting expression of the IFN-γ gene. Polymorphisms in the T-bet gene, TBX21, have been associated with immune-mediated diseases such as asthma and systemic sclerosis. We found that the TBX21 promoter polymorphism T-1993C is associated with a significant decrease in IL-4 and IFN-γ production by stimulated primary human lymphocytes from healthy participants.

Unusual position of external carotid artery: a case report

The arterial pattern of the human body is one of the systems that show a large number of variations. Many reports are available regarding variations of common carotid, external and internal carotid arteries and branches of external carotid artery. We describe a very rare case of lateral position of external carotid artery. The external carotid artery was lateral to the internal carotid artery at the bifurcation of the common carotid artery. The clinical importance of this variation is discussed.

Effect of 5-substituted benzylideneaminosalicylic acid on carrageenan-induced ulcerative colitis

Mesalazine, a drug of choice in the management of ulcerative colitis, was chemically modified as 5-(E)-substituted benzylideneaminosalicylic acid by condensing 5-aminosalicylic acid with selected aryl aldehydes with an intention to improve its pharmacological profile. The tests were performed to study their anti-inflammatory effect on carrageenan-induced ulcerative colitis in albino rats. The histopathological findings, serum transaminase level and lipid peroxide content in the intestine and liver were taken as indices of pharmacological activity. The azomethine derivative formed from salicylaldehyde (5-ASASB3) was found to have maximum activity and it reversed the disease symptoms in experimental animals The azomethine derivative markedly reduces the ulcerative colitis when compared with parent molecule, mesalazine.

Multiparametric quantitation of the perilesional region in patients with healed or healing solitary cysticercus granuloma

The purpose of this study was to compute T2 values and magnetization transfer (MT) ratios in the perilesional region of healing and healed cysticercus granulomas to determine if there are T2 abnormalities not apparent on conventional T2-weighted imaging and to determine the relationship between seizure control and the quantitative measures. Sixty-three patients were studied. T2 values and MT ratios were computed for the perilesional region and were compared with measurements from the contralateral normal-appearing region. A significantly increased T2 value was found for the perilesional region compared to the corresponding contralateral region despite the absence of qualitative abnormality on conventional T2-weighted magnetic resonance imaging. For patients showing normal-appearing perilesional regions on MT imaging, there was no significant difference in T2 and MT ratios between the perilesional and the normal contralateral regions. There was a statistically significant inverse correlation between perilesional T2 values and MT ratios, suggesting each was associated with perilesional gliosis. The study illustrates that quantitative evaluation of MT ratios and T2 augments the qualitative visual assessment of the perilesional region in healing or healed cysticercus granulomas.

Differentiation of calcification from chronic hemorrhage with corrected gradient echo phase imaging

PURPOSE

The purpose of the current study was to prospectively evaluate the role of corrected gradient echo phase imaging in differentiation of calcified granuloma from chronic hemorrhage.

METHOD

Eighty-five patients with single/multiple calcifications and hemorrhages irrespective of their location were studied with corrected gradient echo phase imaging. In all the cases, CT was used as the gold standard for the presence/absence of calcification.

RESULTS

All calcified lesions showed positive phase, whereas chronic hemorrhages showed negative phase in all cases. Five calcified lesions showed no phase shift at TE =15 ms and positive shift at TE = 35 ms. Heterogeneous phase shift was observed in three calcified lesions at TE = 35 ms; all three lesions showed positive phase shift at TE = 15 ms. There was no site-specific problem in differentiation of calcification from chronic hemorrhage including in the basal ganglia.

CONCLUSION

We conclude that calcified granuloma can be easily differentiated from chronic hemorrhage with corrected gradient echo phase imaging, which may obviate the need for CT for its confirmation.

Adenosine and its role in asthma

Endogenous adenosine formed from ADP and AMP by the action of ATPase and 5'-nucleotidase is known to cause bronchoconstriction and asthma in humans. It has been suggested that this action of adenosine is due to its binding to specific purino receptors in the mast cells in the lungs and consequent release of mediators which elicit bronchoconstriction and asthma. The release of these mediators leading to asthma was also believed to be due to vagal stimulation by adenosine. Though the role of adenosine in causing bronchoconstriction leading to asthma is well confirmed the actual mode of action and details of the mechanisms involved in the clinical manifestation of asthma remain unclear.

Traumatic bone cyst--a case report

Traumatic bone cyst is an asymptomatic, slow growing, non expansile lesion commonly diagnosed during routine radiographic examination of the jaw bones. It is more frequently seen in young age, with predilection for anterior region of the mandible leading to a dramatic healing of the lesion. A typical case of traumatic bone cyst in a 12 year old girl is reported. A routine radiologic assessment of the patient with panoramic radiograph revealed a fairly large lesion in the anterior region of the mandible. On surgical exploration, clinical diagnosis was confirmed. Post operative successive radiograph shows progressive osseous healing.

In vitro studies on peroxidative changes leading to hemolysis of erythrocytes infested with malarial parasite Plasmodium vivax

Blood erythrocytes of 25 confirrhed malarial patients infested with P. vivax were analyzed for peroxidation and hemolysis and results compared with 10 uninfected normal control samples. Results indicated significant increase in peroxide formation measured as malondialdehyde, both in presence and absence of H2O2, in parasite infested erythrocytes. These changes induced hemolysis of infected erythrocytes which was increased manifold in presence of H2O2 and could probably be the reason for extensive anemia reported in malaria.

Cytogenetic analysis of peripheral blood lymphocytes of occupational workers exposed to low levels of ionising radiation

The incidence of chromosomal aberrations was analysed in peripheral blood lymphocytes of occupationally exposed people having cumulative doses of 500 mSv. The exposed individuals showed higher frequencies of dicentrics as well as acentrics than normal controls. Absorbed radiation dose was calculated by using in vitro dose response curve established for Cobalt-60 gamma rays. In the control constituting 17 healthy individuals, two dicentrics were detected among 3700 metaphases analysed. In the exposed group 27 dicentrics and one centric ring was detected among 8400 metaphases analysed. Due to small number of dicentrics scored in each individual, the dose estimate suffers from a large statistical uncertainty. The collective dose was found to be 1.89 Gy. This is in good agreement with the corrected physical doses, assuming a mean life of 10 years for the disappearance of lymphocytes. The physical doses accumulated during the last 10 years of occupation were also in good agreement with the biological dose estimate.

Removal of Fluoride from Aqueous Solution by Using Alum Sludge

The ability of treated alum sludge to remove fluoride from aqueous solution has been investigated. The studies were carried out as functions of contact time, concentration of adsorbent and adsorbate, temperature, pH, and effect of concentrations of other anions. The data indicate that treated alum sludge surface sites are heterogeneous in nature and that fits into a heterogeneous site binding model. The optimum pH for complete removal of fluoride from aqueous solution was found to be 6. The rate of adsorption was rapid during the initial 5 minutes, and equilibrium was attained within 240 minutes. The adsorption followed first-order rate kinetics. The present system followed the Langmuir adsorption isotherm model. The loading factor (i.e., the milligram of fluoride adsorbed per gram of alum sludge) increased with initial fluoride concentration, whereas a negative trend was observed with increasing temperature. The influence of addition of anions on fluoride removal depends on the relative affinity of the anions for the surface and the relative concentrations of the anions. Copyright 1998 Academic Press.

Prevention of carbon tetrachloride-induced hepatic injury in mice by Picrorhiza kurrooa

OBJECTIVE

Picrorhiza kurrooa (Pk) has been used in liver diseases in the Indian indigenous system of medicine. We undertook this study to determine whether Pk extract possesses hepatoprotective function and if so to determine its nature and mechanism.

METHODS

Liver injury was induced in 16 mice by thrice-a-week injection of carbon tetrachloride (CCl4) for nine weeks. Eight of them were given daily feeding of Pk extract (12 mg/Kg) 10 days prior to CCl4 injection. Control mice (n = 6) were injected with olive oil for the same period. Serum markers of liver injury and histology of liver tissues were studied. Hepatic glutathione (GSH), total thiol (-SH), glucose 6-phosphate dehydrogenase (G6PD), catalase, lipid peroxidation and plasma membrane-bound Na+/K+ ATPase were also determined.

RESULTS

CCl4 treatment resulted in significant elevation of serum ALT and AST. Liver GSH [6.3 (0.7) vs control 10.5 (1.1) micrograms/mg protein], -SH, G6PD, catalase and membrane-bound Na+/K+ AT-Pase [164.3 (23.2) vs control 358.4 (12.9) nmole pi released/min/mg protein] were significantly reduced. Significant increase of lipid peroxidation [3.0 (0.6) vs control 1.0 (0.3) nmole MDA/mg protein] and histologic changes characteristic of liver injury were also seen. Feeding of Pk extract in CCl4-treated mice caused significantly less alteration of serum ALT, AST, liver GSH [8.9 (0.7) micrograms/mg protein], -SH, G6PD, catalase and membrane-bound Na+/K+ ATPase [270.8 (21.3) nmole pi released/min/mg protein]. Histologic lesions of liver and lipid peroxidation [1.7 (0.4) nmole MDA/mg protein] were also significantly less in these animals.

CONCLUSION

The extract of Pk appears to offer significant protection against liver damage by CCl4. It probably acts as free-radical scavenger and inhibitor of lipid peroxidation of liver plasma membrane.

Glycoprotein components in the serum of patients with cancer breast

The levels of total sialic acid, lipid bound sialic acid and fucose were estimated in the sera of patients with benign and malignant tumours of breast. An increase was noted in all the three parameters, with a more marked increase in malignancy, when compared with benign and controls. Consequent to surgery, there was an elevation in the serum levels of the above parameters than the values prior to surgery and a decline was noted two months after surgery although none of the values reached the normal range. These results suggest a close association of the glycoproteins with the tumour burden and further signify their role in early detection and staging of cancer breast.

Use of chitosan as a biomaterial: studies on its safety and hemostatic potential

Chitosan, a mucopolysaccharide of marine origin, was studied for its safety and hemostatic potential. Its surface was treated with glutaraldehyde, carbodiimide, and plasma glow discharge to elicit effects of enzyme degradation. Of the seven enzymes used, leucine amino peptidase caused maximum degradation. Autoclaving appeared to be an ideal sterilizing method as it caused least decrease in tensile strength and effected a negligible rate of hemolysis. Sterilizing with glutaraldehyde with a physiologic pH retained the maximum tensile strength of chitosan. In vivo toxicity tests indicated that it is nontoxic, and the sterilized films were free of pyrogen. Coagulation and hemagglutination tests showed that the hemostatic mechanism of chitosan seems to be independent of the classical coagulation cascade and appears to be an interaction between the cell membrane of erythrocytes and chitosan.

Studies on Ferric Oxide Hydroxides

Adsorption of selenite (SeO2-3) on different polymorphic forms of iron oxyhydroxides and amorphous ferrihydrite was studied as a function of time, temperature, pH, and concentration of adsorbate(s) and adsorbent(s). Analysis of adsorption data indicates that the surfaces of all the forms of oxyhydroxides and ferrihydrite are heterogeneous in nature and that adsorption fits into a heterogeneous site binding model. The adsorption capacity of oxyhydroxides for SeO2-3 follows the order beta-FeOOH < alpha-FeOOH < gamma-FeOOH < delta-FeOOH < ferrihydrite.

Use of chitosan as a biomaterial: studies on its safety and hemostatic potential

Chitosan, a mucopolysaccharide of marine origin, was studied for its safety and hemostatic potential. Its surface was treated with glutaraldehyde, carbodiimide, and plasma glow discharge to elicit effects of enzyme degradation. Of the seven enzymes used, leucine amino peptidase caused maximum degradation. Autoclaving appeared to be an ideal sterilizing method as it caused least decrease in tensile strength and effected a negligible rate of hemolysis. Sterilizing with glutaraldehyde with a physiologic pH retained the maximum tensile strength of chitosan. In vivo toxicity tests indicated that it is nontoxic, and the sterilized films were free of pyrogen. Coagulation and hemagglutination tests showed that the hemostatic mechanism of chitosan seems to be independent of the classical coagulation cascade and appears to be an interaction between the cell membrane of erythrocytes and chitosan.

Structural studies on bovine bioprosthetic tissues and their in vivo calcification: prevention via drug delivery

Cardiovascular calcification, the formation of calcium phosphate deposits in cardiovascular tissue, is a common end-stage phenomenon affecting a wide variety of bioprostheses. To study the process of calcification in tissue prosthetics, glutaraldehyde-treated bovine pericardium, dura mater and fascialata were implanted subcutaneously in rats and retrieved 21 days later and thereby morphological findings were correlated with biochemically determined levels of calcium. Transmission electron microscopy showed that calcification primarily involved the surface of collagen fibrils and the interfibrillar spaces. The deposition of calcium was higher with dura and fascia prostheses compared to pericardium. However, the release of Fe3+ ions from chitosan matrix had substantially inhibited the deposits of calcium in all implanted tissues. It seems that the structural and anatomical features of the tissue is one of the important factors for tissue-associated calcification. It is also confirmed that glutaraldehyde-preserved pericardium is the most suitable material for the development of cardiac prosthesis, with an appropriate drug combination therapy for prevention of pathological calcification.

Open bone peg epiphysiodesis for slipped capital femoral epiphysis

The records of 43 patients who underwent 64 open bone peg epiphysiodeses for slipped capital femoral epiphysis were retrospectively reviewed. There were 18 unstable and 46 stable slips. The average duration of follow-up was 35 months (range, 12-100). Healing occurred in all cases at an average of 17 weeks after surgery. At the time of healing, 27 hips (42%) showed a change in the degree of slip. At the most recent visit, the head-shaft angle had improved in 19 hips (30%), although the majority of hips showed resorption of the anterior neck prominence. The degree of remodeling showed no correlation with time to healing, duration of follow-up, or the status of the triradiate cartilage. The average operating time and blood loss per hip were 122 +/- 34 min and 426 +/- 238 ml, respectively. Complications included four hips with avascular necrosis and three with chondrolysis, three infections, four delayed wound healings, seven cases of transient anterolateral thigh hypesthesia, and 44 hips with hetertopic ossification. Because of the potential morbidity of this procedure, we no longer perform it as a primary operation for stable slipped capital femoral epiphysis.

Sterilization of chitosan: implications

Chitosan, a biopolysaccharide having structural characteristics similar to glycosaminoglycans, seems to be an ideal non-toxic and bioabsorbable biopolymer. This study highlights the effects of some physical and chemical methods of sterilization on chitosan films, in retaining the original tensile strength besides the efficacy of sterility and degree of hemolysis of the finished films.

Triquetrohamate arthrodesis for midcarpal instability

To assess our results in the management of midcarpal instability with limited wrist arthrodesis, we retrospectively reviewed the records of 10 patients (11 wrists) who had undergone triquetrohamate arthrodesis for symptomatic midcarpal instability. Diagnosis was based on ulnar-side wrist pain, maximum tenderness over the triquetrohamate joint, and characteristic findings on cineradiographic examination. In nine patients, the proximal carpal row suddenly snapped into extension as the wrist was manipulated from radial to ulnar deviation. In one patient (both wrists), the distal carpal row could be dorsally subluxed by direct pressure and axial compression. Both these maneuvers reproduced the patients' symptoms. All cases had failed to improve with prior nonoperative treatment or soft tissue reconstruction. Triquetrohamate arthrodesis was performed to provide midcarpal joint stability. The follow-up time averaged 26 months (range, 6-72). There were two excellent, four good, three fair, and two poor results. Compared to the contralateral side, range of motion averaged 55% flexion, 69% extension, 61% radial deviation, and 64% ulnar deviation, and grip strength averaged 64%. The stability provided by triquetrohamate arthrodesis failed to control symptoms in almost 50% of cases.

Median nerve entrapment after dislocation of the elbow in children. A report of 2 cases and review of literature

Median nerve injury after elbow dislocation is uncommon. Reported are 2 cases of median nerve paralysis caused by entrapment within the elbow joint. For both patients, the diagnosis was made several months after the injury at surgical exploration. This complication occurs almost exclusively in the skeletally immature. A median nerve deficit after reduction of an elbow dislocation in children, especially when associated with a medial epicondylar fracture, should be an indication for surgical exploration and release of the entrapped nerve.

Anorexigenic effect of fecal extract from ventromedial hypothalamic (VMH) lesioned rats on normal rats

Feces of ventromedial hypothalamus (VMH) lesioned obese and sham operated (SL) rats were separately pooled and subjected to column chromatography using sephadex G-150. Fractions showing peak absorption at 280 nm, obtained from respective group of rats were separately pooled and divided into 9 equal aliquots and injected ip in two groups of overnight fasted normal rats (OFN rats). Rats injected with fecal extract from VMH lesioned rats showed decreased food and water intake which was not seen in rats treated with the fecal extract from SL rats suggesting the possible presence of an anorexigenic substance in the feces of VMH lesioned rats but absent in SL rats.

In vitro sensitivity of human Tenon's capsule fibroblasts to mitomycin C and its correlation with outcome of glaucoma filtration surgery

Dose-inhibition studies of proliferating fibroblasts grown from Tenon's capsule biopsy specimens obtained during trabeculectomy from 17 glaucoma patients were performed using varying concentrations of mitomycin C (MMC), with exposure of cells to the drug for either 5 days or 5 minutes. Surgical outcomes were determined 3 months postoperatively. Based on in vitro results, fibroblasts were classified as either MMC-"resistant" or MMC-"sensitive." Thirteen surgically successful cases were associated with 10 "sensitive" and three "resistant" fibroblasts; four surgical failures with one "sensitive" and three "resistant" fibroblasts. The in vitro studies were positively correlated with the clinical outcomes, the former correctly predicting the latter in 76.5% of the surgeries.

Dysplasia epiphysealis hemimelica. Upper limb involvement with associated osteochondroma

Dysplasia epiphysealis hemimelica is a rare developmental disorder characterized by an osteocartilaginous outgrowth arising from 1 or more epiphyses. This condition is generally confined to the lower limb and usually involves either the medial or lateral side of an epiphysis. Reported here is an atypical case that involved the upper extremity and was associated with a typical metaphyseal osteochondroma in the same limb. The occurrence of histologically identical lesions at 2 different sites suggests that the lesions were different modes of expression of the same pathologic process.

Prevention of calcification of tissue valves

In this study an attempt was made to find an optimum method of chemical treatment to prevent the calcification of bioprosthetic heart valves. Bovine pericardium was washed in a 5% sodium chloride solution followed by trypsin (Tr) treatment and was kept in 0.1% glutaraldehyde (GA) with a gradual increase in concentration up to 0.25% GA and finally posttreated with a 4% chitosan (Ch) solution. Fresh, 0.2% GA, 0.625% GA, and sodium chloride-Tr-GA treated pericardial samples were taken for comparative study. Tensile testing showed comparable strength and elongation at the breaking point for all groups. The thermal shrinkage studies indicated merit of the proposed treatment (5% sodium chloride-trypsin-glutaraldehyde treated pericardia with chitosan and without chitosan posttreatment). Collagenase assay showed that all differently treated (GA) materials were equally resistant to collagenase. All samples were implanted subcutaneously in rats for 2, 4, 8, or 12 weeks for calcification study. Morphological and mineral analyses showed complete prevention of calcification in sodium chloride-trypsin-GA-chitosan treated pericardium (Ca was 1.1 +/- 0.27 mg/g, von Kossa 0) at the 12th week of implantation.

Acetabular protrusion secondary to pelvic hemangioma. A case report and review of the literature

Hemangioma of the pelvis is a rare benign tumor. Acetabular protrusion associated with a hemangioma has not been reported previously. A 12 year old girl who had a right sided pelvic hemangioma and protrusio acetabulae was treated over an eight year period. The patient had deterioration of hip function due to progressive acetabular protrusion. Radiotherapy did not appear to prevent tumor infiltration into bone and surrounding soft tissue.

Use of glutaraldehyde-gentamicin-treated bovine pericardium as a wound dressing

Glutaraldehyde (GA)-pretreated gentamicin post-fixed bovine pericardium has been evaluated as a wound dressing in this study. Two excisions approximately 7 x 4 cm, each of full thickness skin, from the upper and lower parts down to, but not including, the panniculus carnosus were made from the back of the guinea pig. The skin excised from the upper part was placed on the wound bed of the lower part as an autograft, whereas the upper wound was closed using 5% sodium chloride-trypsin-0.1% GA-0.048% gentamicin-treated bovine pericardium and sutured for comparative study. The wounds were inspected every 3-6 d for infection and exudation. Histopathological studies were performed at weekly intervals in the post-operative period. At the fifth week, a very thin linear scar on the epidermal aspect without remarkable contracture was observed and histopathology showed the completion of epithelization across the wounds in all cases. This study demonstrates that GA-pretreated, gentamicin-post-fixed bovine pericardium may be used as an alternative biological dressing in the case of large wounds.

Free-space optical mesh-connected bus networks using wavelength-division multiple access

A novel optical free-space mesh-connected bus interconnect network architecture is proposed. A mesh-connected bus [IEEE Trans. Comput. C-30, 264-273 (1981)] is known to have the capability of interconnecting, with a three-stage switching, N nodes with a power distribution loss proportional to √N and is therefore advantageous for networking a large number, say over 1000, of communicating ports. Based on conventional space-invariant optical components in a compact and efficient geometry, the proposed optical mesh-connected bus system concept can be used to build either free-space optical interconnect links for parallel processing applications or central switching systems for local or global lightwave communication networks. The proposed architecture lends itself to networking under both the wavelength-division multiple access and other multiple-access environments. In this paper, based on the wavelength-division multiple-access environment, various optical system implementation and performance issues are discused and parameters are analyzed. It was found that by use of a reasonably compact three-dimensional free-space volume, more than 100,000 dispersion-limited communication nodes at a uniform channel spacing of 0.75 nm can be linked with a moderate power distribution loss of 28 dB. Some preliminary optical wavelength-division multiple-access mesh-connected bus experiments based on a 27 × 27 panchromatic optical source array were performed to confirm the operational principle of the proposed concept.

Halomethane-chlordecone (CD) interactive hepatotoxicity--current concepts on the mechanism

Why is a low dose of toxic chemical nontoxic? What makes a larger dose of the same chemical toxic? Extensive work done to understand the mechanism of halomethane hepatotoxicity and its potentiation by chlorinated insecticide, chlordecone has resulted in the understanding of these basic tenets of toxicology. Studies suggest that ordinarily a small dose of halomethane causes limited liver injury which is accompanied by stimulated tissue repair enabling complete recovery from injury before manifestation. A large dose of halomethane becomes toxic due to suppressed tissue repair, which permits injury to progress in an unchecked fashion. Exposure to very low levels of chlordecone results in highly exaggerated toxicity of ordinarily nontoxic doses of halomethane because of suppressed hepatocellular regeneration and restoration, permitting the progression of liver injury ultimately resulting in liver failure and animal mortality. This concept is further supported by the observation that, while exposure to even high levels of phenobarbital and subsequent low nontoxic doses of halomethane results in greater level of initial liver injury, tissue repair is not completely suppressed; it is slightly postponed by 24 hr, but then much higher rate of tissue repair ensures and consequently enables the animals to completely recover from liver injury and survive. Thus, whether initiation of tissue repair processes occurs or not is the critical determinant in the ultimate manifestation of hepatotoxicity and its end result of either animal death or recovery and survival. Currently understood 'Mechanisms of toxicity' adequately explain only how toxic injury begins. These mechanisms do not permit us to predict the ultimate outcome of toxicity.(ABSTRACT TRUNCATED AT 250 WORDS)

Intraoperative measurement of intraocular pressure in vitrectomized aphakic air-filled eyes using the Tono-Pen XL

The Tono-Pen XL (Bio-Rad, Santa Ana, CA) was compared with manometer readings for intraoperative measurement of intraocular pressure (IOP) in 40 eyes of 40 consecutive patients after vitrectomy, lensectomy, and fluid-air exchange. Tono-Pen readings corresponding to manometer readings of 10, 20, 30, 40, and 50 mmHg were obtained in a masked fashion with a randomized sequence of manometer readings. A correlation was obtained between the manometer and Tono-Pen readings (r = 0.96 in emmetropic eyes and r = 0.93 in myopic eyes). The regression curve that represents the calibration curve of Tono-Pen in terms of the manometer readings for air-filled vitrectomized eyes was obtained. Any Tono-Pen reading can be easily translated into the corresponding manometer reading by referring to the curve. The Tono-Pen can therefore be effectively used to accurately determine intraoperative IOP in eyes undergoing vitrectomy, lensectomy, and fluid-air exchange.

Magnetic resonance imaging in full-term infants with repetitive focal seizures

We report two full-term infants who developed repetitive focal seizures within the first 48 hours of life. Neither infant had predisposing factors and there were no abnormalities on a computed tomography (CT) scan performed on day 2 of life. Magnetic resonance imaging (MRI) performed during the second week of life showed a focal hemorrhagic infarction in both patients. We conclude that either an MRI or a contrast-enhanced CT scan should be obtained within 1 week in patients in whom the initial imaging technique failed to reveal a focal lesion, at which time a cerebral infarction can be diagnosed with greater sensitivity.

Plasticity in the barrel cortex of the adult mouse: effects of chronic stimulation upon deoxyglucose uptake in the behaving animal

We investigated experience-dependent regulation of neuronal activity in the whisker-to-barrel pathway of the adult mouse using the autoradiographic deoxyglucose (DG) method. Animals were placed in the Lausanne whisker stimulator, and three of their whisker follicles were passively stimulated for a period of 1, 2, or 4 d. After this period, mice received a dose of DG and were placed in a cage containing a pile of wooden sticks. Mice that underwent the same procedure except the passive stimulation served as controls. Patterns of stimulus-dependent DG uptake were studied in the somatosensory cortex and in the trigeminal sensory brainstem complex. DG uptake in the barrels corresponding to the passively stimulated whiskers was lower than in controls. This decrease was present throughout the radial extent of a barrel column and was observed in all passively stimulated animals. Quantitative analysis confirmed these observations and, furthermore, showed a statistically significant decrease in DG uptake in barrels neighboring the passively stimulated ones. In half of the animals, the brainstem nuclei showed a decreased DG uptake in the representation of the passively stimulated whiskers, whereas in the other animals the pattern of DG uptake was as in controls. We propose that the signs of cortical plasticity are due to a mechanism that operates in layer IV and functions as a gate for peripheral sensory activity to enter cortical circuitry.

Comparative evaluation of sequestration of polyamines by perfused rabbit and rat lungs

Differences were observed in the sequestration of polyamines putrescine, spermidine and spermine by isolated, ventilated, perfused rat and rabbit lungs, former being able to accumulate more polyamines compared to the latter. Steady state equilibrium was reached earlier for spermine in rat. Isolated ventilated lungs were perfused with harmaline and ouabain, inhibitors known to inhibit the sodium pump at a maximum concentration of 1 mM for rabbit lungs and 0.4 and 0.2 mM for rat lungs, respectively. They did not affect the uptake of polyamines by rat lung but decreased the uptake of putrescine by rabbit lung. Decreased sodium (50 meq/L) in the perfusate increased the uptake of spermine and spermidine by rabbit lung but again showed no effect with rat lung. However, the uptake of polyamines by isolated ventilated rat and rabbit lungs perfused for 60 min with these compounds was linear over the entire range of high concentrations studied. These results suggest that the major uptake process of polyamines by intact lungs of both animal species is primarily by simple diffusion. HPLC analysis of the perfusate and lungs from both animal species post-perfusion indicated no detectable metabolites of the polyamines.

Keratinization of rat vaginal epithelium--V. Modulation of intracellular calcium by estradiol

Changes in the calcium levels under the influence of estradiol were investigated in rat vaginal epithelial cells (VEC). After single estradiol injection, the immature rats showed 1.5-fold increase in Ca2+ levels within 15 min when compared to control animals. Progesterone priming brought calcium levels well below control values throughout the experimental period (up to 12 h). Ca2+ levels in serum did not show any appreciable change. Localization of calcium in VEC with electron microscopy showed aggregates of calcium oxalate on the inner nuclear membrane, nucleolus, mitochondria and keratohyaline granules. After 15 min of estradiol priming, maximum electron density was seen on all these cell organelles mentioned above, however, by 30 min the electron density was reduced considerably and did not increase during the experimental period (up to 12 h).

Immunoelectrophoresis of mycobacterial antigens

Polyvalent antiserum to culture filtrate of H37 Ra M. tuberculosis was raised in rabbits. Monospecific antiserum was raised against M. tuberculosis antigen-5, prepared from the culture filtrates by immunoabsorbent affinity chromatography. On immunoelectrophoresis, antigen-5 demonstrated single precipitin arc against polyvalent and monospecific antisera. The culture filtrate antigen demonstrated multiple precipitin arcs against polyvalent antiserum and single precipitin are against monospecific antiserum. Antigen-5 could be isolated and characterized from the culture filtrate of H37 Ra M. tuberculosis. Immunoelectrophoresis could be one of the method to characterize the mycobacterial antigens prepared in the laboratory.

Sarcoidosis. Report of two cases with oral involvement

Sarcoidosis is a multisystem granulomatous disease in which pulmonary involvement is the most characteristic feature. Even though extrapulmonary manifestations occur infrequently in the area of the head and neck an occasional patient will have oral involvement. As we will demonstrate in these case reports, sarcoidosis should be included in the differential diagnosis of oral and perioral papular lesions noted on examinations of the head and neck.

Perturbations in polyamines and related enzymes following chlordecone-potentiated bromotrichloromethane hepatotoxicity

The mechanism by which chlordecone (CD) amplifies the hepatotoxicity of halomethanes such as CCl4, CHCl3, and BrCCl3 has been a subject of intense study. Recent work has shown that suppression of hepatocellular regeneration leads to accelerated progression of liver injury leading to complete hepatic failure due to an unusual interaction between individually nontoxic low-dose combination of CD and CCl4. Since polyamines are involved in cell division, their levels reflect the extent to which there is suppression of hepatocellular regeneration during CD and CCl4 interaction. The present studies were designed to investigate the polyamine levels and associated enzymes in livers of rats treated with BrCCl3 alone or CD and BrCCl3 low-dose combination in order to confirm whether the sequence of events of hepatotoxicity is similar to that seen in CCl4 toxicity or that seen during CD and CCl4 interaction. The extent of liver toxicity in rats fed 10 ppm chlordecone (CD) for 15 days prior to the injection of a single low dose of BrCCl3 (15 microL/kg body weight) or after exposure to a high dose of BrCCl3 (80 microL/kg body weight) without CD pretreatment, was similar 6 and 24 hr later as assessed by plasma transaminase levels. There was also an increase in transaminase levels, in rats exposed to a single low dose of BrCCl3 alone (15 microL/kg body weight) but this increase was far below the high-dose exposure alone or the combination treatment. Hepatic levels of ornithine decarboxylase, S-adenosylmethionine decarboxylase, N1-acetylputrescine, N1-acetylspermidine, putrescine, spermidine, and spermine at the end of 24 hr increased after exposure to a low dose of BrCCl3 alone as compared to exposure to a high dose alone or the low-dose combination of CD and BrCCl3. Liver spermidine N1-acetyltransferase was elevated at 2, 6, and 24 hr after exposure to a high dose of BrCCl3 alone as compared to treatment with a low-dose combination of CD and BrCCl3 suggesting decreased synthesis of this enzyme, in spite of a greater need as seen from liver transaminase levels. In general, it was observed that there is significant elevation in some polyamines and related enzymes during toxicity of a low dose of BrCCl3 which seemed to stabilize within 24 hr. This was not observed with the other two groups of rats exposed either to BrCCl3 high dose alone or the low-dose combination of CD and BrCCl3.(ABSTRACT TRUNCATED AT 400 WORDS)