Exploring the Mycoplasma capricolum genome: a minimal cell reveals its physiology

We report on the analysis of 214kb of the parasitic eubacterium Mycoplasma capricolum sequenced by genomic walking techniques. The 287 putative proteins detected to date represent about half of the estimated total number of 500 predicted for this organism. A large fraction of these (75%) can be assigned a likely function as a result of similarity searches. Several important features of the functional organization of this small genome are already apparent. Among these are (i) the expected relatively large number of enzymes involved in metabolic transport and activation, for efficient use of host cell nutrients; (ii) the presence of anabolic enzymes; (iii) the unexpected diversity of enzymes involved in DNA replication and repair; and (iv) a sizeable number of orthologues (82 so far) in Escherichia coli. This survey is beginning to provide a detailed view of how M. capricolum manages to maintain essential cellular processes with a genome much smaller than that of its bacterial relatives.

Human complement proteins C3b, C4b, factor H and properdin react with specific sites in gp120 and gp41, the envelope proteins of HIV-1

Recently we reported the basic phenomenon of an interaction between the envelope glycoproteins of HIV-1 gp120 and gp41 and components of the human complement system, i.e. activated C4 (C4b) and activated C3 (C3b) and the complement regulator proteins factor H and properdin. In this study we analyze these interactions in detail. Using 46 overlapping peptides of gp120 attached to microtiter plates, binding of activated human C3 to 6 regions in gp120 was found (aa 100-129, 161-190, 231-250, 301-328, 410-449, 470-499). In competition assays with soluble peptides, representatives of four of these regions were capable to partially inhibit C3b binding to immobilized gp120. Activated human C4 interacted only with peptides covering aa 410-449, but both in direct binding assays and fluid phase inhibition studies. The multi-reactivity of gp120 with C3b was also supported by the fact that gp120 agglutinated erythrocytes coated with C3b. Guided by partial aa sequence homology of gp120 and human C4b binding protein (C4bp) as well as human properdin we detected binding of anti-properdin to aa 100-129 in gp120 and of anti-C4bp to aa 410-449 in gp120. This cross-reactivity was also confirmed by a monoclonal antibody directed against aa 416-443 of gp120, which could be shown to bind C4bp. Interestingly, aa 310-328, part of the V3-loop, were found to show an aa sequence similarity to human complement receptor type 3 (alpha-chain). Consequently, of the 4 (or possibly 6) interaction sites of gp120 with activated human C3, 3 may bind due to imitation of either properdin, CR3 or C4bp. In addition to C4b and C3b, we detected interaction of factor H with gp120; it selectively bound to aa 102-129. Using 14 overlapping peptides of gp41 attached to plates, we identified 4 areas in gp-41 (aa 561-585, 587-605, 615-635, 651-675) which bound human factor H. All of them except the first region partially inhibited factor H binding to gp41 in competition assays with soluble peptides. Properdin bound only to 2 regions (aa 584-614, 651-675). The first 3 sites in gp41 were already shown by us to share homology to sites in human C3. The region around aa 651-675 now also turned out to be similar to human C3. These data demonstrate that the interaction of both, gp120 and gp41, with the complement system is polyvalent and complex.(ABSTRACT TRUNCATED AT 400 WORDS)

Cerebral vein thrombosis in childhood systemic lupus erythematosus

We describe three cases of cerebral vein thrombosis (CVT) in girls with systemic lupus erythematosus. Severe, persistent, unremitting headache was a common manifestation. In the first patient, although the clinical features were suggestive of CVT, the diagnosis was delayed and she had a significant cerebral infarct. In the other two patients the diagnosis was made earlier and led to more rapid treatment; the institution of early therapy may have prevented further sequelae. The CVT was diagnosed in all patients with a combination of computed tomography and magnetic resonance imaging studies without the need for angiography. All patients were treated for their underlying systemic lupus erythematosus and with anticoagulation. All are receiving long-term low doses of warfarin and have not had any recurrences.

[Effect of morphological changes on perfusion and metabolism in cerebral microangiopathy. A comparison of PET, SPECT, and magnetic resonance imaging findings]

51 patients with cerebral microangiopathy were studied with MRI, 18FDG-PET, and 99mTc-HMPAO-SPECT. Exact morphological correlation of MRI-findings to functional data from PET and SPECT was obtained by a special head holder system applied to the patient's head. Patients with less than four lacunar infarctions (LI) and without or only slight deep white matter lesions (DWML) in MRI showed no significantly changed parameters (rMRGlu, rCBF) compared to patients with four or more LI and severe DWML. Patients with medium to severe outer and inner brain atrophy showed significantly lower rMRGlu and rCBF values in both cortex and white matter than patients with no to only slight atrophy. Thus, in patients with cerebral microangiopathy only atrophy and not the presence of LI and DWML is associated with a significant reduction of rCBF and rMRGlu.

Clinical reproducibility of dual energy x-ray absorptiometry

Dual energy x-ray absorptiometry is a technique advocated for the measurement of bone mass throughout the skeleton, and recently it has been used to measure changes in periprosthetic bone mass after joint replacement. The accuracy and precision of the method in clinical patient populations have not been firmly established. This study sought to establish the short-term reproducibility of measurements made with dual energy x-ray absorptiometry of multiple sites in a large sample of elderly patients with rheumatic disease. Reproducibility was assessed in the lumbar spine and in three femoral sites in 69 patients participating in a longitudinal clinical trial. In each patient, absorptiometry was performed twice in the same day at as many as five time points over a 2-year period. The mean (+/- SD) baseline bone density was 0.783 +/- 0.128 g/cm2 for the femoral neck and 1.015 +/- 0.218 g/cm2 for the lumbar spine. The correlations between the duplicate baseline measurements of the spine were excellent (r = 0.9936, p < 0.001) and were stable over the 2-year period; the mean difference between the duplicate baseline measurements was 1.82 +/- 1.54% and the mean coefficient of variation was 1.29%. Measurements in the femur were much less precise; these values were 3.61 +/- 3.14% and 2.55% in the femoral neck, 3.66 +/- 4.35% and 2.59% in the greater trochanter, and 5.28 +/- 5.61% and 3.73% in Ward's triangle. This study evaluated the short-term reproducibility of dual energy x-ray absorptiometry in a clinical population.(ABSTRACT TRUNCATED AT 250 WORDS)

An epidemiologic study of food consumption habits in Germany

Food consumption habits were studied in subgroups of subjects in the German Nutrition Survey (Nationale Verzehrstudie [NVS]) on the basis of body weight. Our study was performed in an 18- to 88-year-old representative subgroup of 2,006 noninstitutionalized volunteers with no significant pathology (known as the Verbundstudie, Ernährungserhebung, and Risikofaktorenanalytik [VERA] subgroup). Using the German Food Code, food and nutrient intakes were calculated from 7-day dietary records. A stratification analysis was used to determine significant differences in food consumption habits of overweight subjects in comparison to normal-weight subjects. The results showed an increase in the prevalence of overweight (body mass index [BMI], 25 to 30) with age, from 15% in the group aged 18 to 24 years to 50% in the group aged more than 55 years. The prevalence of severe overweight (BMI, 30 to 40) increased from 3% to 17% in the same age groups, whereas morbid obesity (BMI, > 40) was found in only 0.4% of the study population. The calculated daily energy intake showed only a very weak correlation with BMI, probably because individual energy requirements and expenditures were not taken into account. However, differences were found between BMI subgroups in terms of the types of food consumed: a high BMI was associated with a higher consumption of meat and meat products but a lower consumption of milk and dairy products and bread and other cereal-based foods.(ABSTRACT TRUNCATED AT 250 WORDS)

[Effect of linguistic competence on speech audiometry results using the Basel Sentence Test]

Linguistic competence, such as a mental lexicon knowledge of syntactic rules of the language and the use of semantic constraints, may impact central speech processing and play an important role in speech recognition. The influence of linguistic ability on speech understanding was investigated using the Basel Sentence Understanding Test. The subject's linguistic ability was determined based upon educational background (elementary school, high school and or university) and intelligence quotients (IQ) based on the reduced version of the Hamburg-Wechsler Intelligence Test. Forty normally-hearing subjects listened to five test forms of the Basel Sentence Understanding Test. Each test form comprised a fraction of 15 low-predictable (LP) test items and 15 high-predictable (HP) test items based on the amount of contextual information in the phrases. No effect of educational background and IQ-value could be demonstrated on the scores of LP sentences. However, there was a small but significant influence of educational background and IQ-value on the scores of HP sentences. The implications of these findings on clinical speech audiometry are discussed.

Seminalplasmin: recent evolution of another member of the neuropeptide Y gene family

Seminalplasmin, the major basic protein of bull semen, an important regulator of calcium transport in bovine sperm and a positive modulator of the zona pellucida-induced acrosome reaction, is shown to be a recently created member of the neuropeptide Y gene family. Sequence analysis of the bovine peptide YY-pancreatic polypeptide gene cluster reveals an unexpected and extensive homology between seminalplasmin and the neuropeptide Y gene family, at the level of both gene structure and primary amino acid and nucleotide sequences. The extremely high degree of homology to the peptide YY gene, in both coding and especially noncoding regions, suggests that the seminalplasmin gene has arisen by a very recent gene duplication of the bovine peptide YY gene. Despite the more than 95% nucleotide sequence identity, a few specific mutations in the seminalplasmin gene have resulted in both the loss of the amino- and carboxyl-terminal cleavage sites characteristic of all other members of the neuropeptide Y family and the acquisition of a function apparently unrelated to the neurotransmitter/endocrine role of peptide YY.

Irreversible repression of DNA synthesis in Fanconi anemia cells is alleviated by the product of a novel cyclin-related gene

Primary fibroblasts from patients with the genetic disease Fanconi anemia, which are hypersensitive to cross-linking agents, were used to screen a cDNA library for sequences involved in their abnormal cellular response to a cross-linking challenge. By using library partition and microinjection of in vitro-transcribed RNA, a cDNA clone, pSPHAR (S-phase response), which is able to correct the permanent repression of semiconservative DNA synthesis rates characteristic of these cells, was isolated. Wild-type SPHAR mRNA is expressed in all fibroblasts so far analyzed, including those of Fanconi anemia patients. Correction of the abnormal response in these cells appears therefore to be due to overexpression after cDNA transfer rather than to genetic complementation. The cDNA contains an open reading frame coding for a polypeptide of 7.5 kDa. Rabbit antiserum directed against a SPHAR peptide detects a protein of 7.9 kDa in Western blots (immunoblots) of whole-cell extracts from proliferating, but not resting, fibroblasts. The deduced amino acid sequence of SPHAR contains a motif found in the cyclins, and it is proposed that SPHAR acts within the injected cell by interfering with the cyclin-controlled maintenance of S phase. In agreement with this proposal, normal cells transfected with an antisense SPHAR expression vector have a significantly reduced rate of DNA synthesis during S phase and a prolonged G2 phase, reflecting the need for postreplicative DNA processing before entry into mitosis.

Regulation of the human poly(ADP-ribosyl) transferase promoter via alternative DNA racket structures

Human nuclear poly(ADP-ribosyl) transferase (ADPRT) protein content in cells suggests that ADPRT expression is stringently controlled. Analysis of the 3 kb promoter sequence, which is required for high level expression, revealed an extraordinary architecture: several Sp1 motifs are located in the vicinity of the first exon but the closest CCAAT/TATA boxes are several hundred basepairs away. Four Alu type repetitive sequences are in the promoter structure. Within these Alu sequences there exist inverted repeat elements, which could form two mutually exclusive types of DNA tertiary structure consisting of quadruplex DNA and loops resembling rackets. Thereby, a CCAAT/TATA element would be moved to spatial vicinity of the Sp1 site activating the promoter. Deletion analysis showed the functional significance of these racket elements. We also obtained evidence for DNA racket structures when we studied mutational mechanisms in a human adenine phosphoribosyltransferase (APRT) deficient patient. One of his alleles harbours a novel complex type of deletion/insertion mutation. Based on several highly informative sequence features in this genomic region a model is proposed for the generation of this unusual type of mutation involving two steps: an initial targeting step and a subsequent complex rearrangement. This process includes the formation of a DNA racket structure, which resembles that of the ADPRT promoter. Thus we conclude that DNA racket structures seem to be of general importance in nature.

Radiologic features of systemic onset juvenile rheumatoid arthritis

OBJECTIVE

To document the radiologic abnormalities in patients with systemic onset juvenile rheumatoid arthritis (SOJRA) including abnormalities occurring early in the course of disease.

METHODS

A retrospective review of the charts and radiographs of 42 consecutive children with SOJRA was carried out. Radiographs were reviewed by a single experienced radiologist with no knowledge of the clinical course of the patients.

RESULTS

Soft tissue swelling and osteoporosis were the most common radiologic abnormalities (34/42; 81%). Cartilage loss and/or bone erosions were also common, occurring in 50% of patients. Erosions occurred within 2 years of disease onset in 11/36 (31%). Subchondral irregularity and sclerosis within 2 years of disease onset preceded erosions in 11 patients with serial radiographs. Severe radiologic abnormalities included joint ankylosis (8/42; 19%), subluxation (9/42; 21%), and protrusio acetabuli (4/42; 10%). Joint ankylosis occurred most commonly between 3 and 5 years after disease onset and subluxation between 2 and 6 years.

CONCLUSION

A subgroup of children with SOJRA develops early destructive radiologic changes whose severity is comparable to those of children with rheumatoid factor positive polyarticular JRA. Early subchondral changes may be predictive of subsequent erosive disease in SOJRA and require prospective study using newer imaging techniques.

Interaction of several complement proteins with gp120 and gp41, the two envelope glycoproteins of HIV-1

OBJECTIVE

To study the binding of human complement proteins to gp41 and gp120 of HIV-1.

METHODS

The interaction of complement proteins with gp41 and gp120 and their effect on the gp41-gp120 complex in enzyme-linked immunosorbent assays (ELISA) and on stably transfected Schneider-2 cells expressing a gp41-gp120 complex was investigated. The molecular basis of these interactions was analysed by computer-supported sequence analysis.

RESULT

gp41 strongly binds human complement regulatory proteins factors H and properdin, and weakly binds factors I and B. The binding occurs with recombinant soluble (rs) gp41 fixed on ELISA plates as well as gp41-gp120 complex expressed on Schneider-2 cells. The basis for this binding potential might be an amino-acid (aa) sequence of gp41 displaying homologies to sites in human C3. rgp120 also binds C3(H2O), a C3b-like form of C3, and C4b. These binding features of gp120 can be explained by homology of constant region (CR) 4 in gp120 to sites in C4b binding protein. Additionally, CR1 in gp120 exhibits a weak similarity to human properdin. Preincubation of rsgp41 with either factor H or properdin, and of rgp120 with C3b or C4b affected the interaction between rsgp41 and rgp120. Incubation of Schneider-2 cells, expressing a functional gp41-gp120 complex, with factor H reduced the detectable amount of gp120. This effect was similar to that induced by soluble CD4.

CONCLUSION

These results strongly suggest that HIV-1 envelope proteins interact with human complement proteins. Additionally, C3b-like features of gp41 and the C3b/C4b binding structures in gp120 may affect the non-covalent association between gp41 and gp120.

Recurrent disk versus scar in the postoperative patient: the role of computed tomography (CT)/diskography and CT/myelography

The purpose of this study was to compare computed tomography (CT)/myelography and CT/diskography images, in a given patient, as a method of distinguishing postoperative fibrosis from recurrent herniated disk material. The study population consisted of 20 patients who had undergone lumbar diskectomy and subsequently developed recurrent radicular pain. All patients underwent CT/myelography and CT/diskography, each procedure performed within 72 h of the other. Comparison of transaxial images from CT/myelography and CT/diskography at a given disk space level yielded the following results: in 12 patients the extradural mass seen via CT/myelography corresponded entirely to the contrast-filled disk fragment seen via CT/diskography (recurrent herniated disk); in three patients the extradural mass seen via CT/myelography was larger than the disk fragment seen via CT/diskography (recurrent herniated disk and fibrosis); and in five patients CT/diskography images appeared normal, but CT/myelography showed an extradural mass (fibrosis). Fifteen patients underwent surgical reexploration with the following results: in three of three patients, the suspicion of recurrent herniated disk and fibrosis by radiologic evaluation was confirmed by surgical reexploration; in nine of 12 patients, solely recurrent herniated disk shown by radiologic criteria was similarly confirmed. The remaining five patients presumed to have fibrosis by radiologic criteria were treated nonoperatively.

[Comparative studies of the use of linear array, curved array and sector technique in sonography of the infant hip]

In an experimental study, the sonographic speed in the hyaline cartilage of the hip of the newborn is measured. With 1549 m/s it lies in the intermediate range of the equipment's pre-set calculation basis. By comparing large groups the study shows that the accuracy of the measurements of the angle alpha is independent of the technology used in the production of the hip sonogram. On the other hand, the image scale has a clear influence. The image scale of 1:1 is inadequate for a reliable repeated cross-sectional presentation and for measurements. The study shows that there are no statistically demonstrable differences when measuring hip sonograms regardless of whether they have been produced using linear array or sector scanning. This is shown both by repeated presentation of the respective cross-section by one and the same researcher and by measurement of identical sonograms by different researchers.

Mental health care for older adults in the year 2020: a dangerous and avoided topic

Low Medicare reimbursement rates are already causing some mental health professionals to turn away elderly patients, restricting access to care. Where will funds come from to pay for the mental health needs of older adults in the year 2020, when 80 million baby boomers pass age 65? This cohort, in contrast to elders today, have high rates of psychiatric illness, and are also much more likely than older adults to seek mental health services. Seemingly oblivious to these trends, plans are being made to cut, rather than expand, the Medicare budget. We are projecting an increasing gap over the next 25 years between need and availability of geriatric mental health services.

The HSSP database of protein structure-sequence alignments

HSSP (homology-derived structures of proteins) is a derived database merging structural (2-D and 3-D) and sequence information (1-D). For each protein of known 3D structure from the Protein Data Bank, the database has a file with all sequence homologues, properly aligned to the PDB protein. Homologues are very likely to have the same 3D structure as the PDB protein to which they have been aligned. As a result, the database is not only a database of sequence aligned sequence families, but it is also a database of implied secondary and tertiary structures.

Transcriptional regulation and autoregulation of the human gene for ADP-ribosyltransferase

Human nuclear poly(ADP-ribosyl)transferase (ADPRT) modifies proteins with branched ADP-ribose-polymers. Various proteins, including ADPRT itself, serve as acceptors for polyADP-ribose. Target proteins include those controlling basic cellular processes such as DNA repair, differentiation and proliferation. Because of the outstanding features of this enzyme: automodification, several functional domains and central role in physiology of the cell, the molecular biology of ADPRT gained wide interest. The promoter structure contains several CCAAT/TATA boxes and SP1 sites. However, there is no CCAAT/TATA box in the neighbourhood of an SP1 site and, thus no obvious site for initiation of transcription. Within this region there are several noteworthy inverted repeats, which by internal basepairing could form two types of cruciform structures. Deletion analysis revealed that these cruciform structures have functional significance. Removal of one type increases the promoter activity, whereas removal of the other diminishes the promoter function. Overexpression of ADPRT from heterologous promoters (MMTV, SV40) leads to repression of the activity of the ADPRT promoter. Indeed, ADPRT was shown to bind specifically to one type of cruciform structure. This specific interaction indicates autorepression of the ADPRT gene: the enzyme ADPRT acts directly as a negative modulator of the activity of its own promoter.

The human ubiquitin-conjugating enzyme UbcH1 is involved in the repair of UV-damaged, alkylated and cross-linked DNA

The human ubiquitin-conjugating enzyme UbcH1 shows 69% identity to the Saccharomyces cerevisiae RAD6/UBC2 which plays a key role in DNA repair. To examine the function of UbcH1 (formerly named E2, M(r) 17,000), [(1990) EMBO J. 9, 1431-1435]) we tested its ability to functionally substitute for yeast RAD6/UBC2 in the recovery of cells from various DNA damage. Complementation by expression of the human UbcH1 cDNA revealed that the UbcH1 carries out the function of S. cerevisiae RAD6/UBC2 in the repair of UV-damaged, alkylated and cross-linked DNA.