Changing characteristics of a colloid cyst of the third ventricle

We describe extremely unusual radiological characteristics in a colloid cyst of the third ventricle, where the cyst became dense and its size decreased following a cerebrospinal fluid diversion procedure. Such a course of events has been reported in colloid cysts only twice in the literature.

Profile of non-compressive myelopathy in eastern India: a 2-year study

Eighty-two patients with non-compressive myelopathy have been studied from July 1994 to June 1996 in Bangur Institute of Neurology and S.S.K.M. Hospital, Calcutta, of which 48 patients were men and 34 patients were women. Presentation was acute in 40 patients (48.78%), subacute in 7 (8.53%), chronic in 27 (32.92%) and history of relapse and remission in 8 (9.75%) patients. Preceding as well as simultaneous fever was observed in 16 cases (19.5%); vaccination (anti-rabies) in 1 case (1.21%); drug abuse in 1 case (1.21%); arthralgia-myalgia and rash in 2 cases (2.42%) and history of electrocution in 2 cases (2.42%). Only pyramidal tract involvement was present in 24 cases (29.26%) and remaining 58 cases (70.73%) had pyramidal tract affection with other sites of involvement. CSF study carried out in 60 cases, revealed rise of protein in 31 (37.8%); oligoclonal band had been detected in 6 (7.31%), pleocytosis in 18 cases (21.95%) and increased IgG index greater than 6.66 in 2 cases (2.42%). CT myelogram done in 23 cases revealed no abnormality. MRI study carried out in 59 cases showed myelomalacia in 1 (1.21%); demyelination plaque in 14 cases (17.07%); atrophy of cord in 3 (3.65%); infarction of cord in 1 (1.21%) and in 40 cases (48.78%) no abnormality could be detected. Etiological diagnosis could be established in 59 (71.95%) cases such as transverse myelitis or myelopathy (post infectious) in 24 (29.26%); demyelination in 16 (19.51%); vascular and vasculitis in 3 (3.65%); toxic in 1 (1.21%); physical (electrocution) in 2 cases (2.42%). In the remaining 23 cases (28.04%) no aetiological factors could be found.

Structure and functional implications of the polymerase active site region in a complex of HIV-1 RT with a double-stranded DNA template-primer and an antibody Fab fragment at 2.8 A resolution

The structure of human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT) complexed with a 19-mer/18-mer double-stranded DNA template-primer (dsDNA) and the Fab fragment of monoclonal antibody 28 (Fab28) has been refined at 2.8 A resolution. The structures of the polymerase active site and neighboring regions are described in detail and a number of novel insights into mechanisms of polymerase catalysis and drug inhibition are presented. The three catalytically essential amino acid residues (Asp110, Asp185, and Asp186) are located close to the 3' terminus of the primer strand. Observation of a hydrogen bond between the 3'-OH of the primer terminus and the side-chain of Asp185 suggests that the carboxylate of Asp185 could act as a general base in initiating the nucleophilic attack during polymerization. Nearly all of the close protein-DNA interactions involve atoms of the sugar-phosphate backbone of the nucleic acid. However, the phenoxyl side-chain of Tyr183, which is part of the conserved YMDD motif, has hydrogen-bonding interactions with nucleotide bases of the second duplex base-pair and is predicted to have at least one hydrogen bond with all Watson-Crick base-pairs at this position. Comparison of the structure of the active site region in the HIV-1 RT/dsDNA complex with all other HIV-1 RT structures suggests that template-primer binding is accompanied by significant conformational changes of the YMDD motif that may be relevant for mechanisms of both polymerization and inhibition by non-nucleoside inhibitors. Interactions of the "primer grip" (the beta12-beta13 hairpin) with the 3' terminus of the primer strand primarily involve the main-chain atoms of Met230 and Gly231 and the primer terminal phosphate. Alternative positions of the primer grip observed in different HIV-1 RT structures may be related to conformational changes that normally occur during DNA polymerization and translocation. In the vicinity of the polymerase active site, there are a number of aromatic residues that are involved in energetically favorable pi-pi interactions and may be involved in the transitions between different stages of the catalytic process. The protein structural elements primarily responsible for precise positioning of the template-primer (including the primer grip, template grip, and helices alphaH and alphaI of the p66 thumb) can be thought of functioning as a "translocation track" that guides the relative movement of nucleic acid and protein during polymerization.

Structures of Tyr188Leu mutant and wild-type HIV-1 reverse transcriptase complexed with the non-nucleoside inhibitor HBY 097: inhibitor flexibility is a useful design feature for reducing drug resistance

The second generation Hoechst-Bayer non-nucleoside inhibitor, HBY 097 (S-4-isopropoxycarbonyl-6-methoxy-3-(methylthiomethyl)-3, 4-dihydroqui noxalin-2(1H)-thione), is an extremely potent inhibitor of HIV-1 reverse transcriptase (RT) and of HIV-1 infection in cell culture. HBY 097 selects for unusual drug-resistance mutations in HIV-1 RT (e.g. Gly190Glu) when compared with other non-nucleoside RT inhibitors (NNRTIs), such as nevirapine, alpha-APA and TIBO. We have determined the structure of HBY 097 complexed with wild-type HIV-1 RT at 3.1 A resolution. The HIV-1 RT/HBY 097 structure reveals an overall inhibitor geometry and binding mode differing significantly from RT/NNRTI structures reported earlier, in that HBY 097 does not adopt the usual butterfly-like shape. We have determined the structure of the Tyr188Leu HIV-1 RT drug-resistant mutant in complex with HBY 097 at 3.3 A resolution. HBY 097 binds to the mutant RT in a manner similar to that seen in the wild-type RT/HBY 097 complex, although there are some repositioning and conformational alterations of the inhibitor. Conformational changes of the structural elements forming the inhibitor-binding pocket, including the orientation of some side-chains, are observed. Reduction in the size of the 188 side-chain and repositioning of the Phe227 side-chain increases the volume of the binding cavity in the Tyr188Leu HIV-1 RT/HBY 097 complex. Loss of important protein-inhibitor interactions may account for the reduced potency of HBY 097 against the Tyr188Leu HIV-1 RT mutant. The loss of binding energy may be partially offset by additional contacts resulting from conformational changes of the inhibitor and nearby amino acid residues. This would suggest that inhibitor flexibility can help to minimize drug resistance.

Results of clinically downstaging cervical cancer in a cytological screening programme

The study was aimed at clinically downstaging cancer of the cervix during a cytological Screening Programme to find out whether such a strategy may help in yielding a large number of early cases of cancer. A cohort of 6,178 women with different cervical lesions were cytologically examined from April 1971 at Queen Mary's Hospital, Lucknow, India. The 8,718 asymptomatic women with healthy cervices were taken as controls. The incidence of cervical dysplasia and malignancy in the study group was found to be 11.2% and 1.9%, which was statistically highly significant compared to control values of 3.3% and 0.02%, respectively. Dysplastic smears were seen maximally in women whose cervix bled to the touch, and the rate of cervical cancer was high in women with suspicious cervix. Dysplastic smears were seen frequently in all age and parity groups, but malignancy was common in women of high age (over 30 years) and high parity (two and above). The incidence of three sexually transmitted diseases, namely Trichomonas vaginalis, Herpes simplex, and condyloma revealed highly significant values, especially in women whose cervix bled to the touch. The study highlights the strategy of clinically downstaging cervical cancer, which is very useful in detecting a large number of dysplasia and frank malignancy cases and also the presence of any associated sexually transmitted pathogens whose treatment would aid in restricting the rising incidence of the dreaded disease in this country.

Irving S. Cooper (1922-1985): a pioneer in functional neurosurgery

Irving S. Cooper (1922-1985), the son of a salesman, worked his way through high school, college, and medical school to become one of the pioneers in functional neurosurgery. He developed several novel techniques for the surgical management of Parkinson's disease and other crippling movement disorders. A keen interest in the physiology of movement disorders was kindled by his doctoral research and continued during his neurosurgical training. He began to apply this knowledge to surgical practice in 1952 when he began his faculty career as Assistant Professor of Surgery at New York University. At the time, surgical treatment of parkinsonian tremor focused on various techniques used to interrupt the pyramidal tract. During a subtemporal approach for a cerebral pedunculotomy, he inadvertently injured and, subsequently, was forced to occlude the anterior choroidal artery. Much to Cooper's surprise, following emergence from anesthesia the patient's tremor and rigidity were abolished without any residual hemiparesis. This serendipitous observation, together with Meyer's earlier work on the role of the basal ganglia in motor control, helped focus surgical efforts on targets within the basal ganglia and, subsequently, within the thalamus to alleviate the movement disorders associated with Parkinson's disease. While at New York University, Cooper developed chemopallidectomy and, later at St. Barnabas Hospital in the Bronx (1954-1977), he used cryothalamectomy as a surgical technique for primary control of tremor in patients with Parkinson's disease. Cooper authored many original papers on surgical techniques and several textbooks on the lives of patients afflicted with Parkinson's disease and other crippling movement disorders. Although considered controversial, this fascinating and complex neurosurgeon made significant contributions to this field.

Metal endoprosthesis for carcinoma esophagus complicating achalasia cardia

A self-expanding metallic esophageal prosthesis was placed in a patient with carcinoma esophagus complicating achalasia cardia. Dysphagia was successfully palliated at 9 months follow up.

Clinicopathologic study of lupus nephritis

Needle biopsies of kidney were done in 35 cases of systemic lupus erythematosus (SLE) with renal lesions. The lupus nephritis were classified according to WHO classification and were correlated with response to therapy and prognosis. Detailed clinical features, routine haematological, biochemical tests (e.g., serum urea, creatinine, total protein and albumin, cholesterol, etc), examination of urine (degree of proteinuria and cells) and occurrence of various auto-antibodies e.g., antinuclear antibody (ANA), anti double stranded DNA (anti DsDNA) by enzyme immunoassay (EIA) method, LE cells and rheumatoid factor (RF) were studied in all cases. Clinically hypertension was present in 19 (54.3%) cases and nephrotic range of proteinuria was detected in 20 (57.2%) cases. ANA was found in 31 (88.5%) cases, anti DsDNA 24 (68.5%) and LE cells were detected in 25 (71.5%) cases. RF was detected in 2 (5.7%) cases. Histologically the most frequent lesions were class IV occurring in 15 cases (42.8%) with initial complete remission achieved only 4 cases by immunosuppressive therapy. Active lesions were also most frequent in this class. Class III lesions were found in 8 (22.8%) cases with 6 cases had complete remission. The best prognosis was noted in class II cases with 4 out of 5 (14.3%) cases had complete remission. Class V lesions were found in 6 (17.2%) cases with complete remission achieved in 3 cases. Only one patient presented with class VI lesion. RF positive cases had milder renal lesions.

Mutational analysis of caveolin-induced vesicle formation. Expression of caveolin-1 recruits caveolin-2 to caveolae membranes

Caveolae are vesicular organelles with a characteristic uniform diameter in the range of 50-100 nm. Although recombinant expression of caveolin-1 is sufficient to drive caveolae formation, it remains unknown what controls the uniform diameter of these organelles. One hypothesis is that specific caveolin-caveolin interactions regulate the size of caveolae, as caveolin-1 undergoes two stages of self-oligomerization. To test this hypothesis directly, we have created two caveolin-1 deletion mutants that lack regions of caveolin-1 that are involved in directing the self-assembly of caveolin-1 oligomers. More specifically, Cav-1 delta61-100 lacks a region of the N-terminal domain that directs the formation of high molecular mass caveolin-1 homo-oligomers, while Cav-1 deltaC lacks a complete C-terminal domain that is required to allow caveolin homo-oligomers to interact with each other, forming a caveolin network. It is important to note that these two mutants retain an intact transmembrane domain. Our current results show that although Cav-1 delta61-100 and Cav-1 deltaC are competent to drive vesicle formation, these vesicles vary widely in their size and shape with diameters up to 500-1000 nm. In addition, caveolin-induced vesicle formation appears to be isoform-specific. Recombinant expression of caveolin-2 under the same conditions failed to drive the formation of vesicles, while caveolin-3 expression yielded caveolae-sized vesicles. These results are consistent with the previous observation that in transformed NIH 3T3 cells that lack caveolin-1 expression, but continue to express caveolin-2, no morphologically distinguishable caveolae are observed. In addition, as caveolin-2 alone exists mainly as a monomer or homo-dimer, while caveolins 1 and 3 exist as high molecular mass homo-oligomers, our results are consistent with the idea that the formation of high molecular mass oligomers of caveolin are required to regulate the formation of uniform caveolae-sized vesicles. In direct support of this notion, regulated induction of caveolin-1 expression in transformed NIH 3T3 cells was sufficient to recruit caveolin-2 to caveolae membranes. The ability of caveolin-1 to recruit caveolin-2 most likely occurs through a direct interaction between caveolins 1 and 2, as caveolins 1 and 2 are normally co-expressed and interact with each other to form high molecular mass hetero-oligomers containing both caveolins 1 and 2.

No evidence for significant linkage between bipolar affective disorder and chromosome 18 pericentromeric markers in a large series of multiplex extended pedigrees

Bipolar affective disorder (BP) is a major neuropsychiatric disorder with high heritability and complex inheritance. Previously reported linkage between BP and DNA markers in the pericentromeric region of chromosome 18, with a parent-of-origin effect (linkage was present in pedigrees with paternal transmission and absent in pedigrees with exclusive maternal inheritance), has been a focus of interest in human genetics. We reexamined the evidence in one of the largest samples reported to date (1,013 genotyped individuals in 53 unilineal multiplex pedigrees), using 10 highly polymorphic markers and a range of parametric and nonparametric analyses. There was no evidence for significant linkage between BP and chromosome 18 pericentromeric markers in the sample as a whole, nor was there evidence for significant parent-of-origin effect (pedigrees with paternal transmission were not differentially linked to the implicated chromosomal region). Two-point LOD scores and single-locus sib-pair results gave some support for suggestive linkage, but this was not substantiated by multilocus analysis, and the results were further tempered by multiple test effects. We conclude that there is no compelling evidence for linkage between BP and chromosome 18 pericentromeric markers in this sample.

Results of a genome-wide genetic screen for panic disorder

Panic disorder is characterized by spontaneous and recurrent panic attacks, often accompanied by agoraphobia. The results of family, twin, and segregation studies suggest a genetic role in the etiology of the illness. We have genotyped up to 23 families that have a high density of panic disorder with 540 microsatellite DNA markers in a first-pass genomic screen. The thirteen best families (ELOD > 6.0 under the dominant genetic model) have been genotyped with an ordered set of markers encompassing all the autosomes, at an average marker density of 11 cM. Over 110,000 genotypes have been generated on the whole set of families, and the data have been analyzed under both a dominant and a recessive model, and with the program SIBPAIR. No lod scores exceed 2.0 for either parametric model. Two markers give lod scores over 1.0 under the dominant model (chromosomes 1p and 20p), and four do under the recessive model (7p, 17p, 20q, and X/Y). One of these (20p) may be particularly promising. Analysis with SIBPAIR yielded P values equivalent to a lod score of 1.0 or greater (i.e., P < .016, one-sided, uncorrected for multiple tests) for 11 marker loci (2, 7p, 8p, 8q, 9p, 11q, 12q, 16p, 20p and 20q).

Burden of care in patents of children suffering from haematological malignancies

The burden of cars experienced by the parents of children suffering from haematological malignancies was the focus of the present investigation. Two groups of children-one with acute lymphoblastic leukaemia (N=23) and the other with hodgkin's disease (N=14) comprised the study sample. The key relatives of these children who also were the caregivers were assessed on a schedule of stressful life events, locus of control, burden of care, and neuroticism. In both groups, the number of stressful life events reported as well as the burden experienced by the relatives were comparable. It was observed that parents had anxiety even though the children were in a state of remission. The importance of recognising the burden experienced in the total management of child with a haematological malignancy is discussed.

Specific interaction of eukaryotic translation initiation factor 5 (eIF5) with the beta-subunit of eIF2

Eukaryotic translation initiation factor 5 (eIF5) interacts with the 40 S initiation complex (40 S.mRNA. eIF3.Met-tRNAf.eIF2.GTP) and mediates hydrolysis of the bound GTP. To characterize the molecular interactions involved in eIF5 function, we have used 32P-labeled recombinant rat eIF5 as a probe in filter overlay assay to identify eIF5-interacting proteins in crude initiation factor preparations. We observed that eIF5 specifically interacted with the beta subunit of initiation factor eIF2. No other initiation factors including the gamma subunit of eIF2 tested positive in this assay. Furthermore, both yeast and mammalian eIF5 bind to the beta subunit of either mammalian or yeast eIF2. Binding analysis with human eIF2beta deletion mutants expressed in Escherichia coli identified a 22-amino acid domain, between amino acids 68 and 89, as the primary eIF5-binding region of eIF2beta. These results along with our earlier observations that (a) eIF5 neither binds nor hydrolyzes free GTP or GTP bound as Met-tRNAf.eIF2.GTP ternary complex, and (b) eIF5 forms a specific complex with eIF2 suggests that the specific interaction between eIF5 and the beta subunit of eIF2 may be critical for the hydrolysis of GTP during translation initiation.

Costs of an emergency department-based accelerated diagnostic protocol vs hospitalization in patients with chest pain: a randomized controlled trial

CONTEXT

More than 3 million patients are hospitalized yearly in the United States for chest pain. The cost is over $3 billion just for those found to be free of acute disease. New rapid diagnostic tests for acute myocardial infarction (AMI) have resulted in the proliferation of accelerated diagnostic protocols (ADPs) and chest pain observation units.

OBJECTIVE

To determine whether use of an emergency department (ED)-based ADP can reduce hospital admission rate, total cost, and length of stay (LOS) for patients needing admission for evaluation of chest pain.

DESIGN

Prospective randomized controlled trial comparing admission rate, total cost, and LOS for patients treated using ADP vs inpatient controls. Total costs were determined using empirically measured resource utilization and microcosting techniques.

SETTING

A large urban public teaching hospital serving a predominantly African American and Hispanic population.

PATIENTS

A sample of 165 patients was randomly selected from a larger consecutive sample of 429 patients with chest pain concurrently enrolled in an ADP diagnostic cohort trial. Eligible patients presented to the ED with clinical findings suggestive of AMI or acute cardiac ischemia (ACI) but at low risk using a validated predictive algorithm.

MAIN OUTCOME MEASURES

Primary outcomes measured for each subject were LOS and total cost of treatment.

RESULTS

The hospital admission rate for ADP vs control patients was 45.2% vs 100% (P<.001). The mean total cost per patient for ADP vs control patients was $1528 vs $2095 (P<.001). The mean LOS measured in hours for ADP vs control patients was 33.1 hours vs 44.8 hours (P<.01).

CONCLUSIONS

In this trial, ADP saved $567 in total hospital costs per patient treated. Use of ED-based ADPs can reduce hospitalization rates, LOS, and total cost for low-risk patients with chest pain needing evaluation for possible AMI or ACI.

Management of hydrocephalus

The present study is an analysis of 747 patients with hydrocephalus, treated and followed up in the Hydrocephalus Clinic run by the department of Paediatric Surgery at the All India Institute of Medical Sciences, New Delhi. The distribution of patients was: congenital-46%, post-meningomyelocoele excision-28%, post-meningitic-21% and others-5% (including post haemorrhagic and post encephalocoele excision hydrocephalus. The average age was 7 months in the shunted group and 10 months in the medical group with overall male to female ratio of 2.3:1. The data were analysed to study the effect of treatment on ventriculomegaly and mental development with special reference to the type of treatment (shunt versus medical) and age at starting treatment. The probability of shunt failure was also studied. A comparison of ventricular size in US/CAT scans between the time of starting treatment and last follow-up revealed improvement in ventriculomegaly in 60% of the shunted patients but only 30% of the medically treated patients. A significant difference was particularly noted in patients with severe hydrocephalus, 72% and 22%, respectively. Comparison of the mean Mental Performance Quotient (MPQ) scores in the shunted & medically treated patients also revealed significantly better MPQ scores in the shunted group (p = < 0.001). Probability of shunt survival, as depicted by the Kaplan-Meier survival curve, revealed that there is a high rate of shunt failure in the first 12 months, followed by a dramatic slowing down. Our observations support the contention that CSF shunt surgery offers better outcome than medical management even when ventriculomegaly is severe at the time of presentation.

Multiple biological roles associated with the Rous sarcoma virus 5' untranslated RNA U5-IR stem and loop

The 5' untranslated region of Rous sarcoma virus (RSV) RNA is a highly ordered structure involved in multiple processes in the viral replication cycle. One of these structures, referred to as the U5-IR stem, is located immediately upstream of the 5' end of the primer binding site. Disruption of its base pairing results in a decrease in initiation of reverse transcription (D. Cobrinik, A. Aiyar, Z. Ge, M. Katzman, H. Huang, and J. Leis, J. Virol. 65:3864-3872, 1991). In the present study, the length of the U5-IR stem structure has been extended by insertions of different sequences which decrease the efficiency of reverse transcription, in vivo and in vitro. Reverse transcription is rescued partially by placing single-stranded bulges into the middle of the extended duplexes. Nucleotide substitutions or insertions into the loop region of the U5-IR stem also decrease the efficiency of reverse transcription, suggesting that these sequences may specifically interact with reverse transcriptase. Surprisingly, all of the extended stem mutations cause significant RNA packaging defects. In contrast, nucleotide insertions or base substitutions in the U5-IR loop do not affect RNA packaging. These data indicate that the reverse transcription initiation complex and RNA packaging apparatus are influenced by the same region of RSV RNA and that each process is differentially sensitive to changes in sequence and/or secondary structure.

Intravenous cyclosporine therapy in the treatment of pyoderma gangrenosum secondary to Crohn's disease

Pyoderma gangrenosum is a destructive, ulcerative skin condition often associated with systemic illnesses such as inflammatory bowel disease, myeloproliferative disorders, and the inflammatory arthritides. We present a patient with long-standing pyoderma gangrenosum associated with Crohn's disease. Multiple deep leg ulcerations were unresponsive over the course of several years to treatment with azathioprine, systemic corticosteroids, 6-mercaptopurine, and dapsone. The patient was hospitalized and treated with a ten-day course of intravenous cyclosporine therapy followed by outpatient oral cyclosporine and showed significant improvement.