Halobacterium vallismortis sp. nov. An amylolytic and carbohydrate-metabolizing, extremely halophilic bacterium

The extremely halophilic bacterium (formerly designated as strain J.F. 54) isolated from salt pools of the Death Valley, California, is a motile, Gram-negative, extremely pleomorphic organism, aerobe, and facultative anaerobe. A variety of carbohydrates are assimilated with or without acid production; soluble starch is hydrolyzed. The organism is not proteolytic; catalase, oxidase, and DNase reactions are positive; Tween 20 is slightly hydrolyzed, but Tweens 40, 60, and 80 are not. Nitrates are reduced to nitrites with gas production; nitrites are not reduced. Optimum growth temperature is 40 degrees C. Growth is inhibited by bacitracin and by novobiocin. The type strain J.F. 54 differs from described species of the genus Halobacterium and is assigned to a new species, Halobacterium vallismortis sp. nov.

Experience with liver and kidney allografts from non-heart-beating donors

Given the shortage of cadaveric organs, we began a study utilizing NHBD for OLTx and KTx. There were 24 NHBD between January 1989 and September 1993. These donors were divided into 2 groups: uncontrolled NHBD (G1) (n = 14) were patients whose organs were recovered following a period of CPR; and controlled NHBD (G2) (n = 10) were patients whose organs were procured after sustaining cardiopulmonary arrest (CA) following extubation in an operating room setting. Eight kidneys and 5 livers were discarded because of macroscopic or biopsy findings. In G1, 22/27 (81.5%) kidneys were transplanted; 14/22 (64%) developed ATN; 20/22 (95%) recipients were off dialysis at the time of discharge. With a mean follow-up of 32.7 +/- 21.1 months, sixteen (73%) kidneys are still functioning, with a mean serum creatinine of 1.7 +/- 0.6 mg/dl. The one-year actuarial patient and graft survivals are 95% and 86%. In G2, 17/20 (85%) kidneys were transplanted; 13/17 (76%) kidneys experienced ATN. All patients were off dialysis by the time of discharge. With a mean follow-up of 17.6 +/- 15.4 months, twelve (70%) kidneys are still functioning, with a mean serum creatinine of 2.5 +/- 2.1 mg/dl. The one-year actuarial patient and graft survivals are 94% and 82%, respectively. In G1, 6/10 (60%) livers were transplanted; 3/6 (50%) livers functioned, the other 3 patients required ReOLTx in the first week postoperatively because of PNF (n = 2) and inadequate portal flow (n = 1). Two functioning livers were lost due to HAT (n = 1) and CMV hepatitis (n = 1). In G2, 6/7 (85.7%) livers were transplanted. All the livers (100%) functioned. 2 patients required ReOLTx for HAT at 0.9 and 1.0 months. Both patients eventually died. One patient with a functioning liver died 2 months post OLTx. The remaining 3 patients are alive and well at 27 months of follow-up. This study shows that the procurement of kidneys from both uncontrolled and controlled NHBD leads to acceptable graft function despite a high incidence of ATN. The function of liver allografts is adequate in the controlled NHBD but suboptimal in the uncontrolled NHBD, with a high rate of PNF.

Properties of proteins MPB64, MPB70, and MPB80 of Mycobacterium bovis BCG

The immunogenic proteins MPB64 and MPB80 of Mycobacterium bovis BCG were purified to homogeneity and compared with MPB70. MPB70 and MPB80 showed a similar distribution in substrains of BCG, both being present in high concentrations in culture fluids of BCG substrain Tokyo, BCG Moreau, BCG Russia, and BCG Sweden and in only very small amounts in BCG Glaxo, BCG Tice, BCG Copenhagen, and BCG Pasteur. In various physicochemical properties MPB70 and MPB80 were closely similar, but MPB80 had a distinctly lower pI value. The N-terminal amino acid sequence was identical for the first 30 residues. In reactions with anti-MPB70 antibodies and delayed-type hypersensitivity skin reactions, MPB70 and MPB80 also had very similar properties. These results show that MPB70 and MPB80 are two closely similar forms of the same gene product, and postsynthetic changes probably explain the observed differences. By contrast, MPB64 had a higher molecular weight. The N-terminal amino acid sequence showed no homology with MPB70, and these two proteins showed no immunologic similarity. MPB64 and MPB70 showed only very restricted cross-reactivity with other species of mycobacteria but cross-reacted with Nocardia asteroides. The similar occurrence in eight different substrains of BCG indicated that the two proteins are influenced by similar control mechanisms, but in contrast to MPB70, MPB64 occurred in sufficient concentration in two strains of Mycobacterium tuberculosis to give a distinct spot in two-dimensional polyacrylamide gel electrophoresis of their culture fluids.

Sequence alignment and evolutionary comparison of the L10 equivalent and L12 equivalent ribosomal proteins from archaebacteria, eubacteria, and eucaryotes

The genes corresponding to the L10 and L12 equivalent ribosomal proteins (L10e and L12e) of Escherichia coli have been cloned and sequenced from two widely divergent species of archaebacteria, Halobacterium cutirubrum and Sulfolobus solfataricus. The deduced amino acid sequences of the L10e and L12e proteins have been compared to each other and to available eubacterial and eucaryotic sequences. We have identified the human P0 protein as the eucaryotic L10e. The L10e proteins from the three kingdoms were found to be colinear. The eubacterial L10e protein is much shorter than the archaebacterial-eucaryotic proteins because of two large deletions, one internal and one at the carboxy terminus. The archaebacterial and eucaryotic L12e proteins were also colinear; the eubacterial protein is homologous to the archaebacterial and eucaryotic L12e proteins, but has suffered rearrangement through what appear to be gene fusion events. Intraspecies comparisons between L10e and L12e sequences indicate the archaebacterial and eucaryotic L10e proteins contain a partial copy of the L12e protein fused to their carboxy terminus. In the eubacteria most of this fusion has been removed by the carboxy terminal deletion. Within the L12e-derived region, a 26-amino acid-long internal modular sequence reiterated thrice in the archaebacterial L10e, twice in the eucaryotic L10e, and once in the eubacterial L10e was discovered. This modular sequence also appears to be present as a single copy in all L12e proteins and may play a role in L12e dimerization, L10e-L12e complex formation, and the function of L10e-L12e complex in translation.(ABSTRACT TRUNCATED AT 250 WORDS)

Frequency of the cholesteryl ester storage disease common LIPA E8SJM mutation (c.894G>A) in various racial and ethnic groups

Cholesteryl ester storage disease (CESD) and Wolman disease are autosomal recessive later-onset and severe infantile disorders, respectively, which result from the deficient activity of lysosomal acid lipase (LAL). LAL is encoded by LIPA (10q23.31) and the most common mutation associated with CESD is an exon 8 splice junction mutation (c.894G>A; E8SJM), which expresses only ∼3%-5% of normally spliced LAL. However, the frequency of c.894G>A is unknown in most populations. To estimate the prevalence of CESD in different populations, the frequencies of the c.894G>A mutation were determined in 10,000 LIPA alleles from healthy African-American, Asian, Caucasian, Hispanic, and Ashkenazi Jewish individuals from the greater New York metropolitan area and 6,578 LIPA alleles from African-American, Caucasian, and Hispanic subjects enrolled in the Dallas Heart Study. The combined c.894G>A allele frequencies from the two cohorts ranged from 0.0005 (Asian) to 0.0017 (Caucasian and Hispanic), which translated to carrier frequencies of 1 in 1,000 to ∼1 in 300, respectively. No African-American heterozygotes were detected. Additionally, by surveying the available literature, c.894G>A was estimated to account for 60% (95% confidence interval [CI]: 51%-69%) of reported mutations among multiethnic CESD patients. Using this estimate, the predicted prevalence of CESD in the Caucasian and Hispanic populations is ∼0.8 per 100,000 (∼1 in 130,000; 95% CI: ∼1 in 90,000 to 1 in 170,000).

CONCLUSION

These data indicate that CESD may be underdiagnosed in the general Caucasian and Hispanic populations, which is important since clinical trials of enzyme replacement therapy for LAL deficiency are currently being developed. Moreover, future studies on CESD prevalence in African and Asian populations may require full-gene LIPA sequencing to determine heterozygote frequencies, since c.894G>A is not common in these racial groups.

Prognosis factors of survival time in patients with glioblastoma multiforme: a multivariate analysis of 340 patients

BACKGROUND

The prognosis of glioblastoma multiforme remains poor despite recent therapeutic advances. Several clinical and therapeutic factors as well as tumour characteristics have been reported as significant to survival. A more efficient determination of the prognostic factors is required to optimize individual therapeutic management. The aim of our study was to evaluate by univariate then multivariate analysis the factors that influence prognosis and particularly survival.

METHODS

Data of 340 patients with newly-diagnosed GBM were retrospectively analyzed. Univariate analysis of prognosis factors of survival time was performed. Factors that seemed determinant were evaluated by Kaplan-Meier survival curves. Finally, the significant factors found in univariate analysis were tested in multivariate analysis using the COX regression method.

FINDINGS

Using multivariate analysis, the following factors were found to influence survival: radiotherapy was the predominant factor followed by radical surgery, tumour location, age and chemotherapy. Patients treated with temozolomide had a markedly better survival rate than patients treated with other chemotherapies (Log-rank test P < 0.005). The values of GBM type (de novo or secondary), as well as repeated surgery and partial surgery (vs. simple biopsy) were suggested by univariate analysis but not confirmed by the COX regression method. After radical surgery, progression-free survival was correlated to overall survival (r = 0.87, P < 10e-5). CONCLUSIONS; The influence of radiotherapy on survival was greater than the influence of age, an argument supporting the proposition of radiotherapy for patients until at least age 70. In the case of recurrence, the correlation between overall survival and progression-free survival is an important factor when considering the therapeutic options. Initial radical surgery and repeated procedures dramatically influence survival. The benefit of partial surgery remains difficult to evaluate. Partial surgery could be used to decrease intracranial pressure and to minimize residual tumours in order to enable treatment by chemotherapy and radiotherapy. The value of temozolomide treatment was confirmed.

Gastroesophageal sphincter pressure and histological changes in distal esophagus in patients with achalasia of the esophagus

A prospective study was performed in 17 patients with achalasia of the esophagus determining the manometric characteristics of the gastroesophageal sphincter, correlating it with histological analysis by biopsies taken during surgery at the distal narrowed segment of the esophagus, at the location of the sphincter. The histological findings were compared to 10 control cases. Presence or absence of ganglion cells at the Auerbach's plexuses and appearance of smooth muscle fibers were evaluated. Only one case (6%) had Chagas' disease. The mean sphincter pressure was 41 mm Hg, with incomplete relaxation in all patients. Histological analysis showed a complete disappearance of ganglion cells in 94% of the cases and a decrease in the number of neurons with marked chronic inflammatory cells in one case (6%). In all control cases, the ganglion cells were normal. Smooth muscle fibers were normal on light microscopy. No relationship was found between resting gastroesophageal sphincter pressure, length and relaxation, and histological findings at the distal esophagus. These findings suggest that the denervation in the majority of cases is located in the Auerbach plexus, with complete absence of ganglion cells and, therefore, absence of postganglionic nerve fibers.

A randomized trial comparing platinum-based chemotherapy followed by radiotherapy vs. radiotherapy alone in patients with locally advanced cervical cancer

Seventy-one patients with stage IIb-IVa cervical cancer were entered on a randomized trial comparing standard pelvic radiotherapy vs. 3 cycles of combination chemotherapy with cisplatin, vinblastine and bleomycin followed by pelvic radiotherapy. Four out of 34 patients randomized to PVB followed by radiotherapy received no PVB and a further 3 patients had only one or 2 cycles of chemotherapy prior to radiotherapy due to drug-related toxicity or progressive disease. After a median follow-up of 3.1 years, no significant difference in survival has emerged between the two randomized groups. However, a difference in the pattern of relapse is emerging with a relatively reduced frequency of systemic relapse in patients receiving chemotherapy prior to local radiotherapy compared to radiotherapy alone. Tumor response was seen following PVB treatment and prior to radiotherapy in 47% of patients. Overall the tumor response rate following completion of radiotherapy was 89% in those treated by radiotherapy and 94% after PVB+radiotherapy. Thirty-three percent of patients randomized to radiotherapy alone relapsed first at a distant (extra pelvic site), and only 18% of patients randomized to initial PVB followed by radiotherapy relapsed systemically initially. When results are presented according to treatment actually given, these trends in patterns of treatment failure are magnified. No treatment-related deaths were reported, and there was no excess of complications with pelvic radiotherapy in the group who had received prior PVB chemotherapy.

A randomized trial of adjuvant chemotherapy after radical hysterectomy in stage Ib-IIa cervical cancer patients with pelvic lymph node metastases

Seventy-one patients with Stage Ib-IIa cervical cancer treated by radical hysterectomy and found to have pelvic lymph node metastases were entered on a randomized trial comparing standard pelvic radiotherapy versus three cycles of combination chemotherapy with cisplatin, vinblastine, and bleomycin followed by pelvic radiotherapy. After a median follow-up of 2.5 years, 24 patients have relapsed. In 12 patients, the first evidence of relapse was in the pelvis, in 11 patients the first relapse was evident at a distant site, and in 1 patient the local recurrence and distant metastases were documented simultaneously. No difference in disease-free or overall survival has emerged between the two treatment groups. Relapse was more common in patients with non-squamous tumors (44%) and in those with metastases in several pelvic lymph nodes. We conclude that patients with pelvic lymph node metastases have a rather poor prognosis, but it remains to be determined how they should best be treated after radical surgery.

MPB59, a widely cross-reacting protein of Mycobacterium bovis BCG

The MPB59 protein of Mycobacterium bovis BCG was purified to homogeneity from culture fluid of BCG substrain Tokyo, and characterized by biochemical and immunological techniques. The molecular weight was 28,000, determined by SDS-polyacrylamide gel electrophoresis, and the pI value was 5.3. The N-terminal amino acid sequence was determined for 32 steps and showed no significant homology with MPB64, MPB70 or MPB80. By crossed immunoelectrophoresis, MPB59 was found to belong to the BCG antigen 85 complex and identified as corresponding to the 85B component of this complex. The protein cross-reacted extensively with other species of mycobacteria, and induced a marked humoral immune response in armadillos and monkeys during development of systemic mycobacterial infection after inoculation with Mycobacterium leprae.

Analysis of growth kinetics by division tracking

Cell division tracking using fluorescent dyes, such as carboxyfluorescein diacetate succinimidyl ester, provides a unique opportunity for analysis of cell growth kinetics. The present review article presents new methods for enhancing resolution of division tracking data as well as derivation of quantities that characterize growth from time-series data. These include the average time between successive divisions, the proportion of cells that survive and the proliferation per division. The physical significance of these measured quantities is interpreted by formulation of a two-compartment model of cell cycle transit characterized by stochastic and deterministic cell residence times, respectively. The model confirmed that survival is directly related to the proportion of cells that enter the next cell generation. The proportion of time that cells reside in the stochastic compartment is directly related to the proliferation per generation. This form of analysis provides a starting point for more sophisticated physical and biochemical models of cell cycle regulation.

Restriction endonuclease analysis of the vp7 genes of human and animal rotaviruses

The vp7 genes of 194 strains of group A rotaviruses representing all known G types were analyzed with three restriction enzymes by direct digestion of amplified cDNA copies or by deduction of the restriction patterns from known sequences. Mammalian rotavirus strains were classified into 28 restriction patterns consisting of combinations of the 6 profiles (s1 to s6) obtained by digestion with Sau96I endonuclease, 9 profiles (h1 to h9) obtained with HaeIII, and 15 profiles (b1 to b15) obtained with BstYI. Digestion with Sau96I and HaeIII identified restriction sites common to all, or almost all, rotavirus strains studied, whereas BstYI was the most discriminating among rotavirus strains. A clear correlation between some restriction patterns or individual profiles and G type and/or host species of origin was found. Several discriminatory restriction sites consisted of type-specific nucleic acid sequences that encoded conserved amino acid residues. Although not directly involved in antigenic diversity, these sites appear to indicate the G type of the isolate. The technique permits rapid comparison of a large number of virus isolates directly from fecal specimens and provides useful markers for investigating the evolution of rotavirus vp7 genes and tracing vaccine virus and interspecies transmission.

Management of cancer of the supraglottis

We present the results of a retrospective study of 903 patients treated with conservation surgery for carcinoma of the supraglottic larynx so we can evaluate our management of supraglottic cancer with different types of surgery. In 301 patients, an extended supraglottic laryngectomy was performed. The recent selective use of transoral laser resection appears to be a rational approach. The 5-year uncorrected survival was 84%, 81%, 76%, and 55% for stages I, II, III, and IV, respectively. The most common site for local-regional failure was the cervical lymphatics. The percentage of occult disease in the NO neck was 21% and epilaryngeal supraglottic location, locally advanced and GIII tumors have a higher frequency of lymph node involvement. There were no differences between comprehensive and anterolateral elective neck dissections. A bilateral elective neck dissection is recommended. In histologically positive neck disease, the survival rates were better with postoperative radiotherapy only in cases of extracapsular spread.

Identification of tuberculosis in cattle slaughtered in Mexico

OBJECTIVES

To determine epidemiologic factors associated with tuberculosis (TB) in dairy cattle slaughtered in 6 important regions for milk production in Mexico.

ANIMALS

2,500 cattle.

PROCEDURE

Tissue specimens with lesions typical of TB were obtained during routine inspection of carcasses at abbatoirs between July 1996 and January 1997. Infection with Mycobacterium organisms was confirmed by histologic examination and bacteriologic culture. Species identification was made by use of selective growth medium, conventional biochemical tests, and radiometric procedures. Epidemiologic information for affected cattle was obtained by personal interviews with cattle dealers and owners.

RESULTS

400 (16%) of 2,500 cattle carcasses had gross lesions typical of TB. Of the 400 infected cattle, 336 (84%) had lesions in > or = 1 lymph node. Infection was confirmed in 87% of cattle with gross lesions by histologic examination, in 77% by bacteriologic culture at a laboratory in the United States, and in 59% by bacteriologic culture at a laboratory in Mexico. Most cattle were adult females in fair to good body condition that came from large herds (> 500 cattle) and were not included in the Mexican TB control program.

CONCLUSIONS AND CLINICAL RELEVANCE

Mean prevalence of lesions typical of TB in dairy cattle at 6 locations in Mexico was 16%. Mycobacterium infection was confirmed by various techniques in most lesions. Recognition of typical gross lesions at slaughter may expedite TB control procedures.

Photoperiod-temperature and neuroblast proliferation-migration in the adult lizard cortex

The lizard medial cortex (a zone homologous to the mammalian fascia dentata) shows delayed postnatal neurogenesis throughout the lifetime of these animals. Experimental lesioning of this area is followed by neuronal regeneration, a unique phenomenon in the adult amniote telencephalon. The differential effects of temperature and photoperiod on postnatal neurogenetic activity were studied using tritiated thymidine pulses and posterior autoradiography as well as proliferating cell nuclear antigen (PCNA) immunostaining. Long (summer) photoperiods increased the number of proliferating neuroblasts in the ependymal neuroepithelium. Cold (winter) temperature prevented migration of the newly generated immature neurones.

Proximal Femoral Nail Antirotation versus Gamma3 nail for intramedullary nailing of unstable trochanteric fractures. A randomised comparative study

The purpose of this study was to compare the clinical results and the complication rates of a new generation of two intramedullary fixation devices: Proximal Femoral Nail Antirotation® (PFNA) and Gamma3®. We conducted a prospective randomised multicentre trial of 61 patients who underwent a PFNA fixation treatment (31 patients) or a Gamma3 nail (30 patients). We documented the fixation failure complications as well as data of the surgical procedure, the clinical and functional outcomes (the EuroQoL5 questionnaire, the Katz index score, the Short Form 36 (SF-36), and the Harris Hip Score) and the plain radiographic parameters at 3,6 and 12 months follow up. The PFNA and Gamma3 fixation devices were similar in terms of complication rates. The risk for experiencing a postoperative complication after Gamma3 nailing was 40% versus 45% after PFNA fixation. At the 6-month and 1-year follow-up evaluations, there were no significant differences in terms of range of motion, clinical scores and radiological outcomes.

Effect of prostacyclin on microvascular pressures in a patient with pulmonary veno-occlusive disease

Continuous-infusion prostacyclin improves symptom scores and decreases mortality in patients with primary pulmonary hypertension, but use of prostacyclin in patients with pulmonary veno-occlusive disease may precipitate pulmonary edema. A patient with pulmonary veno-occlusive disease received a graduated intravenous infusion of prostacyclin and pulmonary capillary pressures were calculated during prostacyclin dose ranging. Calculated capillary pressure increased with low-dose prostacyclin (< or = 6 ng/kg/min) but decreased with higher doses. These data suggest that the post-capillary pulmonary venules in our patient had reversible vasomotor tone, but required a higher dose of prostacyclin to vasodilate than did the precapillary arterioles.

Structure and evolution of the L11, L1, L10, and L12 equivalent ribosomal proteins in eubacteria, archaebacteria, and eucaryotes

The genes corresponding to the L11, L1, L10, and L12 equivalent ribosomal proteins (L11e, L1e, L10e, and L12e) of Escherichia coli have been cloned and sequenced from two widely divergent species of archaebacteria, Halobacterium cutirubrum and Sulfolobus solfataricus, and the L10 and four different L12 genes have been cloned and sequenced from the eucaryote Saccharomyces cerevisiae. Alignments between the deduced amino acid sequences of these proteins and to other available homologous proteins of eubacteria and eucaryotes have been made. The data suggest that the archaebacteria are a distinct coherent phylogenetic group. Alignment of the proline-rich L11e proteins reveals that the N-terminal region, believed to be responsible for interaction with release factor 1, is the most highly conserved region and that there is specific conservation of most of the proline residues, which may be important in maintaining the highly elongated structure of the molecule. Although L11 is the most highly methylated protein in the E. coli ribosome, the sites of methylation are not conserved in the archaebacterial L11e proteins. The L1e proteins of eubacteria and archaebacteria show two regions of very high similarity near the center and the carboxy termini of the proteins. The L10e proteins of all kingdoms are colinear and contain approximately three fourths of an L12e protein fused to their carboxy terminus, although much of this fusion has been lost in the truncated eubacterial protein. The archaebacterial and eucaryotic L12e proteins are colinear, whereas the eubacterial protein has suffered a rearrangement through what appear to be gene fusion events. Within the L12e derived region of the L10e proteins there exists a repeated module of 26 amino acids, present in two copies in eucaryotes, three in archaebacteria, and one in eubacteria. This modular sequence is apparently also present in the L12e proteins of all kingdoms and may play a role in L12e dimerization, L10e-L12e complex formation, and the function of the L10e-L12e complex in translation.

Mechanisms underlying induction of allergic sensitization by Pru p 3

BACKGROUND

Recently, the nature of the lipid-ligand of Pru p 3, one of the most common plant food allergens in southern Europe, has been identified as a derivative of the alkaloid camptothecin bound to phytosphingosine. However, the origin of its immunological activity is still unknown.

OBJECTIVE

We sought to evaluate the role of the Pru p 3 lipid-ligand in the immunogenic activity of Pru p 3.

METHODS

In vitro cultures of different cell types (monocyte-derived dendritic cells [moDCs], PBMCs [peripheral blood mononuclear cells] and epithelial and iNKT-hybridoma cell lines) have been used to determine the immunological capacity of the ligand, by measuring cell proliferation, maturation markers and cytokine production. To study the capacity of the lipid-ligand to promote sensitization to Pru p 3 in vivo, a mouse model of anaphylaxis to peach has been produced and changes in the humoral and basophil responses have been analysed.

RESULTS

The lipid-ligand of Pru p 3 induced maturation of moDCsc and proliferation of PBMCs. Its immunological activity resided in the phytosphingosine tail of the ligand. The adjuvant activity of the ligand was also confirmed in vivo, where the complex of Pru p 3-ligand induced higher levels of IgE than Pru p 3 alone. The immunological capacity of the Pru p 3 ligand was mediated by CD1d, as maturation of moDCs was inhibited by anti-CD1d antibodies and Pru p 3-ligand co-localized with CD1d on epithelial cells. Finally, Pru p 3-ligand presented by CD1d was able to interact with iNKTs.

CONCLUSIONS AND CLINICAL RELEVANCE

The Pru p 3 lipid-ligand could act as an adjuvant to promote sensitization to Pru p 3, through its recognition by CD1d receptors. This intrinsic adjuvant activity of the accompanying lipid cargo could be a general essential feature of the mechanism underlying the phenomenon of allergenicity.

Respiratory failure revealing mitochondrial myopathy in adults

Two patients, a 70-yr-old black woman and a 56-yr-old black man, presented with respiratory failure unexplained by intrinsic lung disease. Both had been dependent on a respirator for several weeks. No abnormalities of the central or peripheral nervous system or long-standing muscle weakness was noted. The findings from ophthalmologic and cardiac evaluations were normal. The serum creatinine kinase concentration was mildly elevated in case 1, and needle electromyography showed myopathic potentials in case 2. In both instances, muscle biopsy established the diagnosis of mitochondrial myopathy. Biochemical studies of muscle extracts showed partial deficiency of complex 3 in patient 2 and of complex 4 in patient 1. Both patients were weaned from the ventilator after long periods of ventilatory assistance. These observations document a hitherto undescribed presentation of adult-onset mitochondrial myopathy.

Organization of genes encoding the L11, L1, L10, and L12 equivalent ribosomal proteins in eubacteria, archaebacteria, and eucaryotes

Archaebacterial and eucaryotic cytoplasmic ribosomes contain proteins equivalent to the L11, L1, L10, and L12 proteins of the eubacterium Escherichia coli. In E. coli the genes encoding these ribosomal proteins are clustered, cotranscribed, and autogenously regulated at the level of mRNA translation. Genomic restriction fragments encoding the L11e, L1e, L10e, and L12e (equivalent) proteins from two divergent archaebacteria. Halobacterium cutirubrum and Sulfolobus solfataricus, and the L10e and L12e proteins from the eucaryote Saccharomyces cerevisiae have been cloned, sequenced, and analyzed. In the archaebacteria, as in eubacteria, the four genes are clustered and the L11e, L1e, L10e, and L12e order is maintained. The transcription pattern of the H. cutirubrum cluster is different from the E. coli pattern and the flanking genes on either side of the tetragenic clusters in E. coli, H. cutirubrum, and Sulfolobus solfataricus are all unrelated to each other. In the eucaryote Saccharomyces cerevisiae there is a single L10e gene and four separate L12e genes that are designated L12eIA, L12eIB, L12eIIA, and L12eIIB. These five genes are not closely linked and each is transcribed as a monocistronic mRNA; the L10e, L12eIA, L12eIB, and the L12eIIA genes are contiguous and uninterrupted, whereas the L12eIIB gene is interrupted by a 301 nucleotide long intron located between codons 38 and 39.

Quasi-collective motion of nanoscale metal strings in metal surfaces

Mass transport processes on metal surfaces play a key role in epitaxial growth and coarsening processes. They are usually described in terms of independent, statistical diffusion and attachment/detachment of individual metal adatoms or vacancies. Here we present high-speed scanning tunnelling microscopy (video-STM) observations of the dynamic behaviour of five-atom-wide, hexagonally ordered strings of Au atoms embedded in the square lattice of the Au(100)-(1x1) surface that reveal quasi-collective lateral motion of these strings perpendicular to as well as along the string direction. The perpendicular motion can be ascribed to small atomic displacements in the strings induced by propagating kinks, which also provides a mechanism for the exchange of Au atoms between the two string ends, required for motion in string direction. In addition, quasi-one-dimensional transport of Au adatoms along the string boundaries may contribute to the latter phenomenon according to density functional calculations.