Gene-based sequence-tagged-sites (STSs) as the basis for a human gene map

Using our data set of 3,143 single pass sequences from human brain cDNA libraries, we have developed a strategy in which gene-based sequence-tagged-sites (STSs), derived from 3'untranslated regions of human cDNAs, are rapidly assigned to megabase-insert yeast artificial chromosomes and somatic cell hybrids to generate regional gene mapping data. Employing this approach, we have mapped 318 cDNAs, representing 308 human genes. Ninety-two of these mapped to regions implicated in human genetic diseases, identifying them as candidate genes. Extension of this strategy has the potential to result in virtually every human gene having, at its 3' end, its own associated STS, with each STS in turn specifying both a corresponding genomic clone and a specific regional location in the genome.

Effects of the German 1993 health reform law upon primary care practitioners' individual performance: results from an empirical study in sentinel practices

An empirical study in Lower Saxony aimed to investigate any changes in primary care physicians' diagnostic and therapeutic strategies as a result of Germany's 1993 health reform act (known as the Gesundheitsstruktur Gesetz or GSG), which included the countrywide implementation of a strict drug budget. A sentinel network consisting of a 37% sample of 350 randomly selected doctors (n = 130, GPs, general internists) was established in Lower Saxony. Four cross sectional surveys, each focussing on one group of health problems, were carried out during 1993. These aimed to show whether sentinel practice networks are suitable for reporting physicians' attitudes towards health care cost containment policies and, secondly, changes in physicians' quantitative and qualitative assessments of the 1993 reform act during its first year of implementation. Participating physicians reported patient consultations (n = 3728). Standardised questionnaires ascertained sociodemographic variables and major reasons for the patients' visit. Data on the diagnoses associated with the patient's main reason for the consultation, the doctor's assessment of the severity of the problem, and diagnostic and treatment strategies were also recorded. The questionnaire focussed on changes in therapy made by the physician together with the reasons for these changes. A number of treatment changes made with regard to cost containment were recorded. During the course of 1993 a decrease in reported changes in treatment was noticed. As expected, some doctors recorded a reduction in successful outcomes of treatment and ascribed this to the reform act. Differences between the four surveys with regard to the influence of the health reform act on the frequency of changes in treatment and the physicians' expectations cannot be explained sufficiently by the physicians' adaptation to the cost containment policies within the year.

HIV positive patients first presenting with an AIDS defining illness: characteristics and survival

OBJECTIVES

To study the presentation and survival of patients who present with their first diagnosis of being HIV positive at the same time as their AIDS defining illness.

DESIGN

Retrospective study of patients presenting with AIDS between 1991 and 1993.

SETTING

Department of genitourinary medicine, St Mary's Hospital, London.

MAIN OUTCOME MEASURES

AIDS defining illness at presentation and survival after diagnosis of AIDS.

RESULTS

Between January 1991 and December 1993, 97 out of 436 patients (22%) presented with their first AIDS defining illness coincident with their first positive result of an HIV test (group B). The remaining 339 patients (78%) had tested positive for HIV-1 infection within the previous eight years and had consequently been followed up in clinics before developing their first AIDS defining illness (group A). The two groups of patients did not differ in age and sex distribution, risk factors for HIV-1 infection, nationality, country of origin, or haematological variables determined at the time of the AIDS defining illness. However, the defining illnesses differed between the two groups. Illnesses associated with severe immunodeficiency (the wasting syndrome, cryptosporidiosis, and cytomegalovirus infection) were seen almost exclusively in group A whereas extrapulmonary tuberculosis and Pneumocystis carinii pneumonia were more common in group B. The survival of patients in group B after the onset of AIDS was significantly longer than that of patients in group A as determined by Kaplan-Meier log rank analysis (P = 0.0026).

CONCLUSIONS

Subjects who are HIV positive and present late are a challenge to the control of the spread of HIV infection because they progress from asymptomatic HIV infection to AIDS without receiving health care. The finding that presentation with an AIDS defining illness coincident with a positive result in an HIV test did not have a detrimental effect on survival gives insights into the effects of medical intervention on disease progression after a diagnosis of AIDS.

Increase of skeletal muscle relaxation speed by direct injection of parvalbumin cDNA

Parvalbumin (PV) is a high affinity Ca(2+)-binding protein found at high concentration in fast-contracting/relaxing skeletal muscle fibers of vertebrates. It has been proposed that PV acts in the process of muscle relaxation by facilitating Ca2+ transport from the myofibrils to the sarcoplasmic reticulum. However, on the basis of metal-binding kinetics of PV in vitro, this hypothesis has been challenged. To investigate the function of PV in skeletal muscle fibers, direct gene transfer was applied in normal and regenerating rat soleus muscles which do not synthesize detectable amounts of PV. Two weeks after in vivo transfection with PV cDNA, considerable levels of PV mRNA and protein were detected in normal muscle, and even higher amounts were detected in regenerating muscle. Twitch half-relaxation time was significantly shortened in a dose-dependent way in transfected muscles, while contraction time remained unaltered. The observed shortening of half-relaxation time is due to PV and its ability to bind Ca2+, because a mutant protein lacking Ca(2+)-binding capacity did not promote any change in physiology. These results directly demonstrate the physiological function of PV as a relaxing factor in mammalian skeletal muscle.

Immunogenicity of the yeast recombinant p17/p24:Ty virus-like particles (p24-VLP) in healthy volunteers

In this Phase I study, immunisation with the yeast-derived p24 virus-like particles Ty p24-VLP (3 x 100 or 3 x 500 micrograms subcutaneously) in 16 healthy male subjects elicited p24 antibody responses in 4 of 16 (25%) subjects. After a fourth, intramuscular, immunisation (500 micrograms), p24 antibody responses were detected in 11 of 15 (70%) subjects. In addition to p24 antibody responses, T cell proliferative responses were also observed, although no HLA restricted p24-specific cytotoxic T cell responses were detected. The results demonstrate that Ty p24-VLP is immunogenic and well-tolerated in healthy male subjects.

The effect of a single amino acid substitution within the V3 loop of HIV-1 gp120 on HLA-DR1-restricted CD4 T-cell recognition

Viral variation has been proposed to play a role in the pathogenesis of human immunodeficiency virus type-1 (HIV-1) infection, and is an important consideration in vaccine design. During the course of an infection, isolates with sequence changes in CD8 T-cell and B-cell epitopes arise. To determine whether sequence variation within the V3 loop of HIV-1 gp120 affects HLA-DR beta 1*0101-restricted CD4 T-cell recognition, we have generated CD4 T-cell clones (TLC) specific to gp120 V3 loop peptides. Four HLA-DR beta 1*0101-restricted groups of TLC were defined by distinct patterns of responses to a panel of peptides, consistent with a highly diverse T-cell repertoire recognizing the 30 amino acid stretch (296-326) of the gp120 V3 loop. Nevertheless, a single residue change at position 311 was found to abolish the recognition of two of the four groups of TLC. This was not due to an effect of the residue at 311 on binding to major histocompatibility complex (MHC), because: (1) irrespective of the residue at 311, peptides competed well with the influenza haemagglutinin peptide 307-319 for binding to cell-bound DR1; and (2) R311-specific TLC were also HLA DR beta 1*0101 restricted. Instead, the substitution of arginine for serine at position 311 blocked the interaction of the peptide with the T-cell receptor. Thus, despite the diversity of the T-cell response to the V3 loop of HIV-1, a single amino acid change can have a considerable influence on the responding T-cell population. As residue 311 is one of the most variable of the V3 loop residues, these results suggest that CD4 recognition can also exert pressure on viral variation consistent with a role for these cells in antiviral immunity.

Vitamin D metabolites modulate osteoblast activity by Ca+2 influx-independent genomic and Ca+2 influx-dependent nongenomic pathways

Previous studies have shown that 1,25(OH)2D3 activates multiple signaling pathways in osteoblasts, including rapid nongenomic and long-term genomic pathways. Genomic pathways are mediated by the vitamin D receptor (VDR), a member of the steroid receptor superfamily, and involve transcriptional regulation of target genes. Nongenomic pathways involve lipid turnover, activation of Ca+2 channels and elevation of intracellular Ca+2, all of which occur within seconds after addition of seco-steroid. The interaction of other physiological metabolites of vitamin D, such as 24,25(OH)2D3, with target cells such as osteoblasts is much less clear. We have used a combination of electrophysiological, biochemical, molecular and ion tracer studies to dissect the physiological responses of osteoblast-like osteosarcoma cells (ROS 17/2.8) to 1,25(OH)2D3 and related metabolites. We conclude the following: 1) the structural requirements for activation of genomic vs. nongenomic pathways by seco-steroid are distinct and likely to involve separate receptors; 2) activation of rapid nongenomic pathways is independent of the long-term regulation of target genes; and 3) 1,25(OH)2D3 and 24,25(OH)2D3 interact at the level of the plasma membrane to regulate Ca+2 permeability. Present studies are aimed toward the understanding of the role of both genomic and nongenomic pathways in osteoblast physiology.

Location and properties of pyrophosphate-binding sites in Escherichia coli F1-ATPase

Binding of pyrophosphate (PPi) to the three catalytic ("C") and three noncatalytic ("NC") nucleotide sites of Escherichia coli F1-ATPase was determined by fluorescence spectroscopy using mutant enzymes with tryptophan inserted specifically in either C sites (beta Y331W) or NC sites (alpha R365W). Fluorescence of the tryptophan is quenched on binding of nucleotide; PPi binding parameters were determined by competition with ATP or adenyl-5'-yl imidodiphosphate. It was found that MgPPi binds to each NC site with Kd = 20 microM. In contrast, even at millimolar concentration, neither MgPPi nor free PPi showed significant binding to C sites. We confirmed that free PPi displaces nucleotide from C sites, but this was shown to be due to complexation of Mg2+ ions rather than to occupancy of the sites. MgPPi bound at NC sites was found not to affect ATP hydrolysis rates. From the data we propose a two-phase model for nucleotide binding at NC sites. In phase one, NC sites recognize the pyrophosphate "end" of the nucleotide, which binds initially with Kd similar to MgPPi; in phase two, a slow conformational change occurs which tightly sequesters adenine nucleotide. Phase two does not occur with guanine nucleotide. This model explains the preference of NC sites for adenine nucleotides. Pi (5 mM) did not bind to either C or NC sites.

Fucoidin, a polysaccharide inhibiting leukocyte rolling, attenuates inflammatory responses in experimental pneumococcal meningitis in rats

It is presumed that adjuvant therapy rather than new antibiotics will improve the prognosis of pneumococcal meningitis. We investigated the effect of fucoidin, a polysaccharide inhibiting leukocyte rolling, on inflammatory changes in experimental meningitis in rats. After induction of meningitis by pneumococcal cell wall components, regional cerebral blood flow and intracranial pressure increased over the observation period of 6 h. At the end of the experiments, cerebrospinal fluid pleocytosis and brain water content were higher in animals with meningitis than without. Fucoidin treatment in the meningitis group reduced all inflammatory changes, whereas fucoidin treatment of animals without meningitis increased blood white cell count, but had no effect on any other parameter. Our results confirm that selectins are involved in the early phase of pneumococcal meningitis and possibly are a target for adjunctive therapy.

In vitro effects of low-calcium peritoneal dialysis solutions on peritoneal macrophage functions

The use of low-calcium peritoneal dialysis solutions (PDS) for continuous ambulatory peritoneal dialysis is becoming widely accepted to reduce the risk of serum hypercalcemia in patients taking calcium salts as phosphate binders. We compared the in vitro effects of low-calcium PDS (1,000 mumol calcium/L), calcium-free buffer, and buffers with increasing calcium concentrations (500 to 5,000 mumol calcium/L) on peritoneal macrophage (PMO) functions. Peritoneal macrophages isolated from 10 continuous ambulatory peritoneal dialysis patients were incubated in the different solutions and tested for phagocytic and killing capacity, superoxide generation (cytochrome-C reduction and lucigenin-enhanced chemiluminescence), and the rate of myeloperoxidase-dependent oxidative metabolism (luminol-enhanced chemiluminescence). All functions of the PMO incubated in calcium-free buffer were significantly suppressed compared with the PMO incubated in calcium buffers. No dose-dependent increase of a single PMO function could be found after incubating the PMO in calcium buffer with increasing concentrations. Incubation of PMO in otherwise identical PDS containing 1,000, 1,450, or 1,750 mumol calcium/L did not result in significantly different PMO functions. Acidic PDS (pH 5.3 to 5.5) suppressed all measured PMO functions as compared with their neutralized counterparts (pH 7.4), irrespective of the calcium concentration. Results of our in vitro study show that low-calcium PDS does not suppress PMO functions any more than standard-calcium PDS (1,750 mumol calcium/L) does.

Evaluation of safety and efficacy of 3TC (lamivudine) in patients with asymptomatic or mildly symptomatic human immunodeficiency virus infection: a phase I/II study

In a phase I/II study, 7 levels of 3TC therapy (from 0.5 to 20.0 mg/kg/day) were studied in 104 asymptomatic and mildly symptomatic human immunodeficiency virus-infected patients with CD4 cell counts < or = 400 x 10(6)/L. Mild and transient episodes of diarrhea, headache, fatigue, nausea, and abdominal pain were the most frequent events reported. No dose-limiting toxicities were observed. Small and transient increases in CD4 cell counts were detected during the first 4 weeks of treatment. These were followed by progressive declines during prolonged therapy. Sustained decreases in beta 2-microglobulin, neopterin, and p24 antigen levels were seen over the 52-week study. There was no consistent dose-response correlation for any surrogate marker. Penetration of 3TC into cerebrospinal fluid (CSF) was in the same range as reported for ddC and ddI; the mean CSF-to-serum ratio was 0.06. These findings indicate that 3TC exhibits an excellent safety profile and has antiretroviral activity at the dosages studied.

Limits of two-dimensional planimetry in the follow-up of glaucomatous optic discs

BACKGROUND

To test the intra-observer, intra-photographic variability of two-dimensional measurements of the optic nerve head we used computer-assisted planimetry. Depending on the variability, we calculated the confidence intervals of the optic disc parameters which could be indicative of glaucomatous damage on follow-up.

METHODS

Slides of the optic disc were taken from 10 eyes of 10 patients (n = 6 open angle glaucoma, n = 4 ocular hypertension) using a Zeiss fundus camera. All eyes were evaluated 10 times within a random sequence on 10 different days. We obtained the absolute values of the disc radii and the cup radii in steps of 1, 10, and 45 deg in predefined quadrants and the mean radii.

RESULTS

The confidence interval of the cup radius on follow-up, depending on sector size, ranged between 62 and 38% for small cups (radius 0.2 mm) and between 12 and 7% for large cups (radius 0.8 mm). The confidence intervals of the cup/disc ratio distinguishable from the disc boundary, depending on sector size, ranged between 0.81 and 0.89 for small discs (radius 0.5 mm) and from 0.90 to 0.94 for large discs (radius 1.0 mm). The confidence intervals of the cup/disc ratio indicating an increase on the cup radius in follow-up, distinguishable from the boundary of the disc, ranged, depending on sector size, between 0.57 and 0.75 for small discs (radius 0.5 mm) and from 0.81 to 0.89 for large discs (radius 1.0 mm).

CONCLUSION

The smaller the disc, the more difficult is the detection of glaucomatous damage, and the larger the cup, the more difficult is the detection of progression of glaucomatous damage.

[Liver transplantation in familial amyloidosis]

A 32-year-old Portuguese with hereditary amyloidosis had been suffering from polyneuropathy for 9 years. It began insidiously with polyneuropathic complaints in the legs which gradually got worse over the years and progressively impaired walking. He also had signs of autonomic neuropathy with severe orthostatic dysregulation, abnormal micturition and impotence. His general state had deteriorated during the last 3 years with a weight loss of 18 kg, due to treatment-resistant diarrhoea. As there is so far no known cure of the amyloidosis, which usually ends fatally from cachexia after an average of 10 years, liver transplantation was performed to reduce amyloid production and thus favourably influence the course of the disease. The patient's general condition has remained stable 32 months after the transplantation.

Naturally occurring variants of human T-cell leukemia virus type I Tax protein impair its recognition by cytotoxic T lymphocytes and the transactivation function of Tax

There is a high degree of intraisolate sequence heterogeneity in the tax gene of human T-cell leukemia virus type I (HTLV-I), although the sequence variation between patients is small compared with that of human immunodeficiency virus type 1. In the present study, we investigated whether naturally occurring amino acid substitutions changed the properties of the Tax protein in two respects: first, recognition of the protein by cytotoxic T lymphocytes (CTL), and second, the ability of the Tax protein to transactivate various promoters. We found that (i) all of the observed amino acid substitutions that occur in known CTL epitopes abolished the recognition of the synthetic peptide representing the respective epitope; (ii) these substitutions occurred significantly more frequently in subjects carrying HLA-A2; and (iii) most of the amino acid substitutions severely reduced the ability of Tax protein to transactivate three promoters: the HTLV-I long terminal repeat, the c-fos promoter, and the interleukin-2 receptor alpha chain promoter.

Validating gender-specific defining characteristics of altered sexuality

The authors conducted a retrospective study to validate gender-specific defining characteristics for the proposed nursing diagnosis altered sexuality. An investigator-designed tool was used to collect data from 100 randomly selected members of NANDA. The Fehring method of diagnostic content validity was used to identify major and minor defining characteristics for men and women. The defining characteristics identified and validated encompass all dimensions of human sexuality, and are more concise and descriptive of this human response than those currently in use. Findings of this study will be used to develop a tool for assessment of altered sexuality in a variety of populations and settings.

Production and analysis of transgenic mice with ectopic expression of parvalbumin

Transgenic mice expressing rat parvalbumin under the control of the human metallothionein IIA (MTII A), SV-40 early, and neuron-specific enolase (NSE) promoters were produced. Ectopic expression was analyzed by RNA polymerase chain reaction and RNase protection in combination with immunohistochemistry. From a total of 25 transgenic lines 18 were found to express the transgene. Expression strength and tissue specificity were dependent upon the promoter used and varied considerably among animal lines produced with the same construct. Highest constitutive MT IIA-driven expression was found in lung, liver, heart, and kidney, as well as in brain, and lower amounts of transgene expression were found in spleen, testis, and muscle. Immunohistochemistry of tissue sections of metallothionein-parvalbumin transgenic strain 29 in the non-induced state revealed that ectopic PV mRNA is translated into protein. Short-term induction of the MT IIA promoter by CdSO4 or CdCl2 leads to a shift in tissue specificity and does not increase ectopic expression in tissues where the transgene is active in the noninduced state. As expected the NSE promoter showed highest activity in brain. However, NSE-driven expression could also be detected to various degrees in all investigated tissues. SV-40-dependent PV expression showed no tissue preference and varied considerably among different strains. Except for the observation that the SV-40-PV construct showed lower yields in transgenic production and reduced numbers of positive offspring no obvious impairment of growth or behavior as a consequence of transgenic PV expression could be detected.

Spatiotemporal gait parameters measured using the Bessou gait analyzer in 79 healthy subjects. Influence of age, stature, and gender. Study Group on Disabilities due to Musculoskeletal Disorders (Groupe de Recherche sur le Handicap de l'Appareil Locomoteur, GRHAL)

The Bessou gait analyzer provides quantitative measurements of spatiotemporal gait parameters. The purpose of this study was to determine whether and how these parameters are influenced by age, stature, and gender. Seventy-nine normal individuals (38 males aged 20 to 80 years and 41 females aged 20 to 80 years) were divided into ten-year age groups. Males and females were studied separately. In each subject, the Bessou gait analyzer was used to measure spatiotemporal gait parameters (spatial parameters: stride and step lengths; temporal parameters: cycle, stance and swing durations). Mean walking speed was calculated in each subgroup. In both males and females, all study parameter values were identical for the left and right sides. Females younger than 60 years had shorter stride and step lengths (M: 1.5 +/- 0.2 m; F: 1.3 +/- 0.1; p < 0.001) but faster pace values (M: 104.8 +/- 9.0 cycles/min; F: 115.6 +/- 7.6 cycles/min; p < 0.001) than males, and consequently mean walking speed was similar in females and males (M: 4.8 km/h +/- 0.8 km/h; F: 4.4 km/h +/- 0.6 km/h). In contrast, females older than 60 years walked at the same pace as males and consequently had slower walking speeds. Stride length was correlated with age, stature, and gender. However, age was correlated with stature, and only age and gender had independent effects on gait parameters in the multiple regression analysis. In subjects of similar age and gender, effects of stature may need to be taken into account.

Biological dosimetry after extensive diagnostic x-ray exposure

The yield of chromosome aberrations (dicentric and ring chromosomes) was determined for five patients who had been extensively exposed to diagnostic x rays. Remarkably high aberration yields were obtained for each of them leading to correspondingly high equivalent whole body doses ("biological dosimetry"). The contribution of iodized contrast media and computing tomography to the biologically estimated doses is discussed.