Current trends in the diagnosis and management of cystic hydatid disease of the liver

Cystic hydatid disease caused by Echinococcus granulosus most commonly involves the liver. Recent years have seen many changes in modalities of diagnosis and treatment of cystic disease in the liver. Currently used methods of immunodiagnosis, newer radiological modes of imaging, emerging non-surgical techniques of management and the impact of minimal access surgery in this disease are highlighted in the present review.

Mechanisms of action of intravenous immune globulin in immune-mediated diseases

Intravenous immune globulin (IVIG) exhibits a number of immunomodulatory properties that are mediated by the Fe portion of IgG and by the spectrum of variable (V) regions contained in the immune globulin preparations. Five predominant and non-exclusive mechanisms of action have been proposed to account for the immunomodulatory effects of IVIG in immune-mediated diseases: (i) functional blockade of Fc receptors on splenic macrophages; (ii) inhibition of complement-mediated damage, an effect that is dependent on the ability of IgG to bind C3b and C4b and thus reduce the number of activated complement fragments that may deposit on target surfaces of complement activation; (iii) modulation of the production of cytokines and cytokine antagonists; (iv) neutralization of circulating autoantibodies by complementary (e.g. anti-idiotypic) antibodies in IVIG, a mechanism that accounts for the rapid decrease in titre of circulating autoantibodies that is often observed within hours following the infusion of IVIG; (v) selection of immune repertoires, a complex set of effects that may be observed in individuals receiving IVIG far beyond the half-life of the infused immunoglobulin and that is directly relevant to the ability of IVIG to, for example, suppress autoantibody-producing clones in patients with antibody-mediated autoimmune disease and modulate graft versus host disease (GVHD). IVIG has been shown to downregulate or activate B-cell clones expressing surface IgG that is complementary (anti-idiotypic) to V regions of antibodies present in IVIG. IVIG has been shown also to interact with surface molecules of T cells that are essential to immune regulation, such as the alpha beta TCR, CD5, CD4, non-polymorphic determinants of MHC class I molecules and adhesion molecules of T and B cells. The complex interactions of IVIG with functional molecules of cells of the immune system are relevant to its therapeutic effects in T cell- as well as B cell-mediated diseases and indeed, to our understanding of the physiological role of normal IgG and antibody networks in controlling autoreactivity in healthy individuals.

Corticotropin-releasing factor decreases vasogenic brain edema

We report the first series of studies comparing the anti-edematous effects of human corticotropin-releasing factor (hCRF) and dexamethasone in an experimental model of vasogenic peritumoral brain edema. Both hCRF and dexamethasone effectively decreased blood-brain barrier (BBB) permeability of intracerebral RG2 gliomas in rats as observed by contrast-enhanced T(1)-weighted magnetic resonance imaging. A decrease in the water content of tumor and peritumoral brain tissue was observed with proton-density magnetic resonance imaging and confirmed by direct wet/dry tissue measurements. The calculated ED(50) for hCRF was 59 micrograms/kg s.c. twice a day, and that for dexamethasone was 0.61 mg/kg i.m. twice a day; the hCRF:dexamethasone dose-potency ratio was 120:1 on a molar basis. The anti-edematous action of hCRF is not mediated by the release of adrenal corticosteroids. A direct action of hCRF on the tumor microvasculature results in restoration of BBB integrity and up-regulation of BBB-specific protein expression. The average survival time with chronic treatment was prolonged significantly in the hCRF-treated group (35 days) compared with the dexamethasone-treated group (28 days; P < 0.05) and the saline-treated control group (22 days; P < 0.0001). hCRF, as an alternative to corticosteroid therapy, may provide substantial benefits with respect to reducing the major side effects encountered with long-term, high-dose corticosteroid treatment.

Basal and vitamin D-responsive activity of the rat osteocalcin promoter in stably transfected osteosarcoma cells: requirement of upstream sequences for control by the proximal regulatory domain

Osteocalcin (OC) is a bone-specific vitamin D- responsive protein that is developmentally expressed during osteoblast differentiation. In transient transfection assays, as little as approximately 0.1 kilobase (kb) of the OC proximal promoter is sufficient for basal expression. Because eukaryotic genes are packaged as nucleosomes that contribute to both chromatin organization and transcriptional control, we functionally examined the activity of OC promoter constructs within a chromatin context. ROS 17/2.8 osteosarcoma cells were stably transfected with a series of rat OC promoter-reporter constructs, containing progressive 5'-deletions. The results demonstrate that in contrast to transient transfection assays, the proximal 0.11-kb promoter is no longer active when integrated in the genome. Progressive gain of basal expression with 0.35-, 0.53-, and 0.72-kb promoters suggests that upstream sequences facilitate the formation of an appropriate higher order nuclear structure, thereby potentiating the activity of the chromosomally integrated proximal promoter elements. This is consistent with location of both deoxyribonuclease I (DNase I)-hypersensitive sites and nuclear matrix protein-DNA interaction sites in the osteocalcin promoter. Vitamin D responsiveness in the stably transfected cells is obtained with the inclusion of 0.53 kb or additional upstream promoter sequences. Therefore, these sequences satisfy the requirements for binding of basal and enhancer transcription factors as well as interactions between them within a chromatin context. Both maximal basal expression and maximal vitamin D responsiveness are obtained with cells carrying either the 0.72-kb or the 1.1-kb promoter fragment. Cells carrying the 1.1-kb promoter show DNase I hypersensitivity at both the basal promoter and the vitamin D response element-containing domains, locations that also exhibit DNase I hypersensitivity in the endogenous OC promoter. In addition, we have documented changes in the basal activity and vitamin D responsiveness of the stably integrated 1.1 kb promoter as a function of cell density-mediated growth inhibition, which is accompanied by up-regulation of bone phenotypic genes. Thus, important aspects of OC gene transcriptional regulation that cannot be investigated in transient transfection assays can be addressed using ROS 17/2.8 cells stably transfected with OC promoter-reporter constructs.

Imaging the expression of transfected genes in vivo

Imaging the expression of successful gene transduction has been demonstrated in vivo for the first time by using an appropriate combination of "marker gene" and "marker substrate" in an experimental animal model. The herpes simplex virus 1 thymidine kinase (HSV1-tk) gene was selected as an example of a marker gene, and the recombinant STK retrovirus containing HSV1-tk was used to transduce RG2 glioma cells in vitro and in vivo. RG2TK+ cell lines expressing the HSV1-tk gene and three potential marker substrates for the HSV1-TK enzyme were evaluated. Radiolabeled 5-iodo-2'-fluoro-2'deoxy-1-beta-D-arabinofuranosyluracil (FIAU) was shown to be a substantially better marker substrate for the HSV1-TK enzyme than 5-iodo-2'-deoxyuridine or ganciclovir. The magnitude of FIAU accumulation in different RG2TK+ clones corresponded to their sensitivity to ganciclovir and to the level of HSV1-tk mRNA expression. Imaging the expression of HSV1-tk in transduced RG2 tumor cells was demonstrated in animals using quantitative autoradiography; 2-[14C]FIAU accumulation was shown to be high in RG2TK+ brain tumors growing in one hemisphere and very low in nontransduced RG2 tumors in the contralateral hemisphere. Transduction of RG2 tumor cells with the HSV-tk gene in vivo resulted in tumors which accumulated FIAU to high levels and produced clearly defined images. Given the level of FIAU accumulation in the transduced tumors, it is likely that a clinically applicable method for imaging HSV1-tk gene expression can be implemented using existing clinical imaging techniques.

Comparison of multiple-marker screening with amniocentesis for the detection of fetal aneuploidy in women > or = 35 years old

OBJECTIVE

Our purpose was to compare the multiple-marker screening test with elective amniocentesis for the detection of fetal Down syndrome and other aneuploidies in women aged > or = 35.

STUDY DESIGN

Our database included the multiple-marker screening test (maternal serum alpha-fetoprotein, human chorionic gonadotropin, unconjugated estriol, and maternal age) and genetic amniocentesis results from 1942 women aged > or = 35. A Down syndrome risk > or = 1:190 was considered screen positive. An algorithm to detect trisomy 18 was also used.

RESULTS

The multiple-marker screening test Down syndrome screen-positive rate was 26.1% (507/1942). The Down syndrome detection rate was 75% (33/44); the trisomy 18 detection rate was 75% (3/4). However, the multiple-marker screening test detection rate for all aneuploidies was only 61%. Missed aneuploidies included trisomy 21, sex chromosome abnormalities, trisomy 13, trisomy 22, and trisomy 18.

CONCLUSIONS

The multiple-marker screening test fails to detect approximately 39% of all fetal aneuploidies in women aged > or = 35. These data should be provided to women considering prenatal diagnosis so that they can make an informed decision regarding the multiple-marker screening test versus amniocentesis for advanced maternal age.

Recombinant thyrotropin containing a beta-subunit chimera with the human chorionic gonadotropin-beta carboxy-terminus is biologically active, with a prolonged plasma half-life: role of carbohydrate in bioactivity and metabolic clearance

Recombinant TSH is now successfully being used in clinical studies of thyroid cancer. Because of its therapeutic potential, we have constructed a longer acting analog of TSH by fusing the carboxy-terminal extension peptide (CTEP) of hCG beta onto TSH beta. When coexpressed either with alpha-subunit complementary DNA or alpha minigene in African green monkey (COS-7) and human embryonic kidney (293) cells, the chimera was fully bioactive in vitro and exhibited enhanced in vivo potency associated with a prolonged plasma half-life. The addition of 25 amino acids with 4 O-linked oligosaccharide chains did not affect the assembly and secretion of chimeric TSH. Wild-type (WT) and chimeric TSH secreted by COS-7 and 293 cells displayed wide differences in their plasma half-lives, presumably due to the presence of terminal sialic acid and SO4 on their oligosaccharide chains, respectively. Chimeric and WT TSH secreted by both cell lines demonstrated similar bioactivity in cAMP production, with some differences in [3H]thymidine incorporation. Chimeric TSH appears to be more effective in COS-7 cells than in 293 cells, as judged by growth assay. COS-7-produced chimeric TSH showed the maximum increase in half-life, indicating the importance of sialic acid in prolonging half-life and in vivo potency. Sulfation of both subunits, predominantly beta and to a lesser extent alpha, appears to be responsible at least in part for the increased metabolic clearance of WT and chimeric TSH secreted by 293 cells. Apart from its therapeutic potential, chimeric TSH produced in various cell lines can be used as a tool to delineate the roles of sulfate and sialic acid in the in vivo clearance and, thereby, the in vivo bioactivity.

RG-2 glioma growth attenuation and severe brain edema caused by local production of interleukin-2 and interferon-gamma

Two aspects of cytokine therapy of intracerebral tumors are considered in this study: modulation of tumor growth in vivo and central nervous system toxicity. Coimplantation of RG-2 glioma cells and retroviral vector producer cell lines was performed to provide a local source of interleukin-2 (IL-2) or IFN-gamma within the tumor and coinitiate an antitumor immune response. We demonstrated that local intratumoral production of IL-2 and IFN-gamma generates a cell-mediated antitumor response in vivo. This response was manifest as a diffuse infiltration of monocytes/macrophages, CD4+ and CD8+ T cells, and activation of microglial OX42+ cells in intracerebral RG2 tumors. The cell-mediated antitumor immune response resulted in the early suppression of intracranial and subcutaneous tumor growth, but the effect was not sustained and there were no tumor regressions. The absence of increased survival of animals with intracranial tumors is explained in part by the severe central nervous system toxicity caused by local production of IL-2 and IFN-gamma. Central nervous system toxicity induced blood-brain barrier disruption, vasogenic brain edema, and dislocation of the brain midline structures, as observed by dynamic magnetic resonance imaging and direct measurements of tissue water content. The clinical application of IL-2 and IFN-gamma gene transfer therapy for intracerebral tumors must consider the potential for severe vasogenic brain edema associated with intracerebral production of these cytokines.

MTS1/p16/CDKN2 lesions in primary glioblastoma multiforme

The multiple tumor suppressor 1 (MTS1) gene encoding the p16 inhibitor of cyclin-dependent kinase 4 is deleted or mutated in a wide variety of human tumor cell lines, but the importance of this gene as a tumor suppressor in vivo appears to be highly dependent on tumor type. Because MTS1/p16/CDKN2 and the homologous MTS2/p15 gene map to a region of chromosome 9p21, which is frequently deleted in malignant gliomas, we searched for lesions of these genes in primary biopsies of glioblastoma multiforme (GBM). Our analysis confirms a sizable frequency of homozygous deletion of MTS1/p16/CDKN2 (9/27 cases) and also reveals a low but detectable frequency of intragenic DNA lesions (one point mutation in exon 2 leading to premature termination) among GBMs that retain one or both copies of the gene. No mutations were found in exon 2 of MTS2/p15 (12 cases examined), and one GBM showed a DNA deletion breakpoint in the 30 kb between MTS1/p16/CDKN2 and MTS2/p15 resulting in deletion of MTS1/p16/CDKN2 with retention of MTS2/p15. In contrast to the high-grade tumors, none of 12 low-grade gliomas showed MTS1/p16/CDKN2 deletions. These data support a role for MTS1/p16/CDKN2 as a tumor suppressor gene in the in vivo evolution of GBMs. Given that two tumors with hemizygous MTS1/p16/CDKN2 deletions and loss of heterozygosity for chromosome 9p21 did not contain detectable intragenic mutations, there may be one or more additional relevant 9p21 tumor suppressor genes.

Imaging of brain tumor proliferative activity with iodine-131-iododeoxyuridine

METHODS

Iodine-131-iododeoxyuridine (IUdR) uptake and retention was imaged with SPECT at 2 and 24 hr after administering a 10-mCi dose to six patients with primary brain tumors. The SPECT images were directly compared to gadolinium contrast-enhanced MR images as well as to [18F]fluorodeoxyglucose (FDG) PET scans and 201Tl SPECT scans.

RESULTS

Localized uptake and retention of IUdR-derived radioactivity was observed in five of six patients. The plasma half-life of [131I]IUdR was short (1.6 min) in comparison to the half-life of total plasma radioactivity (6.4 hr). The pattern of [131I]IUdR-derived radioactivity was markedly different in the 2-hr compared to 24-hr images. Radioactivity was localized along the periphery of the tumor and extended beyond the margin of tumor identified by contrast enhancement on MRI. The estimated levels of tumor radioactivity at 24 hr, based on semiquantitative phantom studies, ranged between < 0.1 and 0.2 microCi/cc (< 0.001% and 0.002% dose/cc); brain levels were not measurable.

CONCLUSIONS

Iodine-131-IUdR SPECT imaging of brain tumor proliferation has low (marginal) sensitivity due to low count rates and can detect only the most active regions of tumor growth. Imaging at 24 hr represents a washout strategy to reduce 131I-labeled metabolites contributing to background activity in the tumors, and is more likely to show the pattern of [131I]IUdR-DNA incorporation and thereby increase image specificity. Iodine-123-IUdR SPECT imaging at 12 hr and the use of [124I]IUdR and PET will improve count acquisition and image quality.

Fluorescence array detector for large-field quantitative fluorescence cytometry

A prototypic fluorescence array detector (FAD) has been designed and constructed which is capable of quantifying single-cell fluorescence emissions from a statistically significant population of cell-sized objects (over 10(3)) on a solid substrate. The system is comprised of a cryogenically cooled CCD, 50 mW air-cooled argon ion laser, and optics that image a large (1 x 1 cm) field at 1:1 (no magnification). The CCD is effectively treated as a two-dimensional array of 2.7 x 10(5) independent 20 x 20 microns photodetectors, with each cell-sized object imaged across only a few CCD pixels. Algorithms have been developed for focusing, image segmentation, shading correction, and noise rejection; performance data for the FAD with fluorescent calibration beads are presented. The FAD is a simple alternative to microscope-based imaging cytometry, allowing large-field imaging without a scanning stage.

Meningiomas of the cranial base

Treatment objectives for meningiomas of the cranial base include relief of neurologic disability and prevention of clinical progression or recurrence with the least morbidity. Recent advances in skull base surgical techniques, through an appreciation of skull base anatomy and institutional specialization, have contributed major improvements to the outlook for patients with these tumors, and previously inoperable cases may now often be removed completely with acceptable risk. Since significant morbidity may be incurred during surgical resection of these difficult lesions, especially in terms of cranial nerve dysfunction, the value of aggressive surgical resection must be weighted against the often indolent natural history of these lesions, and must be individualized in each patient. Completeness of resection is the major prognostic factor determining the outcome of patients with typical benign meningiomas in terms of length of survival, risk of recurrence, and neurological disability. Various means of prognosticating the growth potential of a given tumor are being investigated, though none have yet been confirmed for their predictive value in typical, histologically benign meningiomas. The role of external beam radiotherapy has not been subjected to adequately controlled, prospective studies, and there is currently insufficient followup to assess the risks and benefits of stereotactic radiosurgery. Advances in the clinical management of tumors of the skull base has had perhaps the greatest impact for patients with meningiomas who constitute a large portion of tumors seen in these locations. Although the majority have benign histological features, skull base meningiomas can present a formidable challenge due to their proximity to vital structures, surgical inaccessibility, and occasional aggressive features. The combination in recent years of advances in skull base surgical techniques, adjuvant therapy, and rehabilitation methods have dramatically improved the outcome for these tumors.

Rhabdoid tumour of kidney. A case report

A case of rhabdoid tumour of kidney, a rare but more aggressive tumour of early childhood, is reported. The important histological, histogenetic and prognostic differences between rhabdoid and Wilm's tumour are discussed.

Compendium of dietary sources of vitamin A in the Thar desert

The undisputed long term solution to prevent nutritional blindness lies in changing the dietary habits of a given population through nutritional education, nutritional supplementation, and nutritional rehabilitation. Before such strategies can be successfully implemented, it becomes necessary to study the existing dietary pattern of the population and to identify locally grown foods rich in vitamin A. Seventy eight rural women were interviewed to determine the common dietary items in western Rajasthan. These items were then matched with their B-carotene contents, only to discover that, 100 grams of any of them would not provide the RDA for a 1-3 year old child, with the exception of Suva (Peucedanum graveolens) and Bathua (Chenopodium album) leaves. The B-Carotene contents of several food items is unknown at present and there is an urgent need to evaluate them.

Aqueous kinetics of sisomicin sulphate

Sisomicin sulphate is a new-generation aminoglycoside with a broad spectrum of antimicrobial activity that includes Pseudomonas aeruginosa. It is superior to gentamicin against indole-negative Proteus and some resistant strains of Pseudomonas. The ocular pharmacokinetics of sisomicin have not been explored. We used the agar diffusion technique of microbial assay to determine the aqueous penetration and bioavailability of a subconjunctivally placed standard dose of 20 mg/0.4 ml of sisomicin sulphate in 20 human volunteers undergoing elective cataract surgery. A peak concentration of 16.4 mg/l was found in the aqueous humour 78 minutes after injection, which is 65 times the minimum inhibitory concentration for Pseudomonas. The antibiotic was bioavailable up to 1203 minutes after injection in a concentration of 0.9 mg/l, which easily covers the minimum inhibitory concentration of Staphylococcus aureus and Pseudomonas. The antibiotic disappears from the aqueous humour at the 1434 minute interval (approximately 24 hours). The elimination half-life (t1/2 of sisomicin was determined to be 5.16 hours (K = 0.134/hour) and the aqueous clearance was 2.87 microliters/min.

Xerophthalmia clinics in rural eye camps

Even though the primary prevention of many eye diseases can be effectively incorporated into the existing pattern of rural eye camps, efforts in this direction are restrained and insubstantial. We describe our technique and experience in the prevention of xerophthalmia by organising a distinct entity called a xerophthalmia clinic in our eye camps. The clinic consists of an Ophthalmologist or an Ophthalmic assistant who will exclusively examine children who come to the eye camp. This is perhaps, the first report on rural xerophthalmia clinics, in ophthalmic literature. Over a seven year period from 1984 to 1990 we have conducted 71 xerophthalmia clinics amongst the ninty eye camps organised. A total of 11,370 children were examined in the xerophthalmia clinic out of which 18.9% were afflicted with the disease. Therapeutic doses of Vitamin A were administered on the spot to the afflicted and prophylactic doses were administered to the rest. Intensive health education efforts are made through clinics to effectuate change in dietry habits towards consumption of locally grown DGLV (Dark Green Leafy Vegetables) like Anthenum, chenopodium and Amaranthus. A bipronged offensive consisting of mega-dosing and health education is, for the present and the foreseeable future, the best strategy to combat xerophthalmia in this desert region. A year by year breakdown of prevalence rates in the present study shows that in years of severe drought the prevalence of xerophthalmia increases three fold over the non-drought or mild drought years, thereby demonstrating that drought is a substantial risk factor in developing countries leading to vitamin A deficiency and xerophthalmia.

DNA sequence analysis and comparison of the variable heavy and light chain regions of two IgM, monoclonal, anti-myelin associated glycoprotein antibodies

The complete variable heavy and light chain gene sequences of two monoclonal, IgM, anti-myelin associated glycoprotein (MAG) antibodies associated with peripheral neuropathy, are presented. Comparative analysis of the two VH regions has revealed that they are 88% homologous to one another and are both members of the VH3 gene family. They are also highly homologous to a gene which is frequently utilized in the fetal B-cell repertoire. The V kappa light chain gene of one of the antibodies is 99% homologous to a V kappa II gene and the V lambda light chain gene of the other antibody is only 72% homologous to other known V lambda genes. Further analysis of V genes utilized by anti-MAG antibodies should reveal the structural basis for their binding activity.

Biochemical and morphometric analyses in hypoplastic lungs

We report the results of biochemical and morphometric studies on lungs of infants with bilateral lung hypoplasia either with or without oligohydramnios (OH or NOH) in comparison with findings in normally grown lungs. The OH and NOH lungs were equally hypoplastic in terms of DNA content but OH lungs had a significantly lower disaturated phosphatidylcholine (DSPC) concentration than NOH or normal lungs, apart from a subgroup with gastrointestinal or airway obstruction. Hydroxyproline concentration in OH lungs was higher than that in NOH or normal lungs. Desmosine concentrations did not differ significantly between groups despite the obvious lack of elastin in the septal crests of the OH group on histology. Morphometry revealed low lung volume, low radial alveolar counts, low alveolar numbers, and low alveolar surface area in both OH and NOH groups. Alveoli and alveolar ducts constituted a higher proportion of lung volume in NOH than in OH lungs. The similarity of most morphometric indices in the two groups implies that maturation does not depend on quantitative elaboration of airways and alveoli. The finding of impaired epithelial maturation despite the high hydroxyproline concentration in the OH lungs suggests an abnormality in epithelial-mesenchymal interaction that is not present in the equally small lungs of the NOH group.