Detection and treatment of twinning: an improvement and new results

This work deals with two aspects of the twinning problem. Firstly, an improvement of a known statistical test aimed at detecting twinning is presented and, secondly, a new parametrization of twinning is described, as well as a new method to obtain an accurate estimate of the degree of twinning. During work on crystals of the dimerization-initiation site of the HIV-1 genomic RNA, perfectly twinned crystals were obtained which were not immediately recognized as such by use of a known statistical method. This method, reminiscent of Wilson tests for the detection of centrosymmetric space groups, relies on calculation of <F2>/<F>2 or, equivalently, of <I2>/<I>2. It is shown that overlooking experimental errors may lead to erroneously large values of this index and, in turn, to ambiguous or incorrect conclusions. An immediate solution to this problem is presented. Independently, an alternative parametrization which expresses both the effect of twinning on intensities and the operation of untwinning to recover the correct intensities is proposed. A new method for estimating the degree of twinning is also presented. It is based upon maximization of the cross-correlation coefficients between intensities of all available data sets, and yields a fully analytical solution. Tests made with experimental data are quite satisfactory. It is suggested that the latter results could be used efficiently within the MIR method by allowing refinement, through one additional parameter only, of the twinning ratios of all data sets considered for phasing. Finally, the new parametrization of twinning has striking consequences in this correlation-based twinning determination: very unexpectedly, it yields a novel estimate of the 'twinning ratio' of a potentially twinned crystal which is fully independent of the data set used for the comparison.

Stenting small coronary arteries

Stenting of small coronary arteries was long contra-indicated because of a high rate of subacute occlusion. We report a single-center registry including 190 patients stented with 2.5 mm balloons. Procedural success was 98% and subacute occlusion rate was 2.6%. Clinical follow-up showed a 24.5% repeat intervention rate. These results seemed acceptable, warranting stent implantation in small arteries in the case of acute or threatened closure. New stent designs and coatings may contribute to the improvement of outcomes and to the decrease in subacute occlusion and restenosis rates.

Trace element content of commercial shampoos: impact on trace element levels in hair

Popular shampoos were screened for their contents in trace elements, using ICP-MS detection in a semi-quantitative mode. Hair samples from volunteers were analyzed before and after hair washing with selected shampoos to demonstrate the effect of the contamination and the impact on occupational medicine. While some shampoos showed high levels of certain elements, the degree of contamination on the hair was found to be negligible. Only one shampoo tested, formulated with selenium sulfide, was found to seriously contaminate the hair.

Oral etoposide for patients with metastatic gastric adenocarcinoma

PURPOSE

Oral administration of etoposide represents a pharmacokinetic advantage over the traditional intermittent intravenous usage of this drug. This phase II trial was undertaken to determine its activity against gastric adenocarcinoma in chemotherapy-naive patients.

PATIENTS AND METHODS

Patients with measurable, unresectable, metastatic gastric carcinoma with performance status < or = 2 by Zubrod scale were eligible. Patients had to have normal liver, renal, and bone marrow functions. Written informed consent was obtained from all patients. The starting dose of etoposide was 50 mg/m2/day, given orally daily for 21 days, followed by a 7-day rest period. Oral etoposide was repeated every 28 days. Response was evaluated after two courses.

RESULTS

Twenty-eight patients were registered. The median number of courses was two (range, 1 to 12; total, 69 courses). Twenty-six patients were evaluable for response and toxicity. Five patients (19%; 95% confidence interval, 3% to 35%) achieved a partial response. The median duration of response was 3.5 months. There was no treatment-related death. Toxic effects were mild to moderate.

CONCLUSIONS

Oral etoposide is modestly active against gastric carcinoma. It is well tolerated by patients. Further studies in combination with other active agents against gastric carcinoma may be warranted.

Protection against necrosis but not apoptosis by heat-stress proteins in vascular smooth muscle cells: evidence for distinct modes of cell death

We have reported previously that cultured vascular smooth muscle cells (VSMC) isolated from spontaneously hypertensive rats (SHR) show higher proliferation and cell death than normotensive controls. In addition to protecting cells against death, heat stress proteins (HSPs) appear to play a role in cell proliferation. This investigation examines the involvement of HSP72 and HSP27 in altered SHR VSMC proliferation and death. We have performed detailed discriminatory analysis to characterize which type of VSMC death is induced by heat stress (HS) and serum deprivation. Serum deprivation induced apoptosis (caspase-3 cleavage and DNA laddering) and secondary necrosis, the 2 processes being a continuum of each other. In contrast, acute HS (46 degrees C, 30 minutes), which inhibited BN. lx and SHR VSMC proliferation by 2-fold, increased necrosis (by 5-fold and 2-fold, respectively) but not apoptosis. HSP72 and HSP27 expression evoked in VSMC by mild HS (44 degrees C, 15 minutes) 6 hours before acute HS prevented the inhibition of proliferation and induction of necrosis with no effect on serum deprivation-induced or staurosporine-induced apoptosis. This induced expression of HSP72 and HSP27 did not eliminate the higher basal proliferation, apoptosis, and necrosis of SHR VSMC compared with BN.lx VSMC, suggesting that these HSPs are not involved in altered SHR VSMC proliferation and death. Also, although apoptosis and necrosis may be a continuum, in VSMC the 2 processes may be distinguished by HS, in which only necrosis is prevented by prior HSP accumulation. This observation may be of use in designing strategies for cellular protection.

Response to neoadjuvant chemotherapy best predicts survival after curative resection of gastric cancer

OBJECTIVE

In Western populations, long-term survival rates after curative resection of gastric cancer remain extremely poor. The lack of effective adjuvant therapy has prompted the evaluation of neoadjuvant approaches. Since 1988, we have conducted three separate phase II trials using neoadjuvant chemotherapy to treat patients with potentially resectable gastric cancer. The present study was conducted to evaluate whether response to neoadjuvant chemotherapy is predictive of survival in patients with resectable gastric cancer.

METHODS

Eighty-three patients with pathologically confirmed gastric adenocarcinoma were treated with neoadjuvant chemotherapy before planned surgical resection. Response was assessed by upper gastrointestinal series, endoscopy, computed tomography scan, and pathologic examination.

RESULTS

For the three phase II trials, clinical response rates ranged from 24% to 38%. Three patients (4%) had a complete pathologic response. Sixty-one patients (73%) underwent a curative resection. Median follow-up was 26 months. Univariate analysis revealed T stage, number of positive nodes, and response to chemotherapy to be significant predictors of overall survival. However, on multivariate analysis, response to chemotherapy was found to be the only independent prognostic factor.

CONCLUSIONS

Response to neoadjuvant chemotherapy is the single most important predictor of overall survival after neoadjuvant chemotherapy for gastric cancer. These findings support further evaluation of neoadjuvant approaches in the treatment of this disease.

Evaluation of the contamination of marine algae (Seaweed) from the St. Lawrence River and likely to be consumed by humans

The goal of the study was to assess the contamination of marine algae (seaweeds) growing in the St. Lawrence River estuary and Gulf of St. Lawrence and to evaluate the risks to human health from the consumption of these algae. Algae were collected by hand at low tide. A total of 10 sites on the north and south shores of the St. Lawrence as well as in Baie des Chaleurs were sampled. The most frequently collected species of algae were Fucus vesiculosus, Ascophyllum nodosum, Laminaria longicruris, Palmaria palmata, Ulva lactuca, and Fucus distichus. Alga samples were analyzed for metals (As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, and Zn), iodine, and organochlorines. A risk assessment was performed using risk factors (e.g., RfD of the U.S. EPA, ADI of Health Canada, etc.). In general, concentrations in St. Lawrence algae were not very high. This was especially true for mercury and the organochlorines, concentrations of which were very low or below detection limits. Consequently, health risks associated with these compounds in St. Lawrence algae were very low. Iodine concentration, on the other hand, could be of concern with regard to human health. Regular consumption of algae, especially of Laminaria sp., could result in levels of iodine sufficient to cause thyroid problems. For regular consumers, it would be preferable to choose species with low iodine concentrations, such as U. lactuca and P. palmata, in order to prevent potential problems. Furthermore, it would also be important to assess whether preparation for consumption or cooking affects the iodine content of algae. Algae consumption may also have beneficial health effects. Scientific literature has shown that it is a good source of fiber and vitamins, especially vitamin B12.

Crystallization of the dimerization-initiation site of genomic HIV-1 RNA: preliminary crystallographic results

The genomic RNA of all retroviruses is encapsidated in virions as a dimer of single-stranded chains held together near their 5'-end. For HIV-1, the initial site of dimerization has been shown to be a hairpin with a nine-residue loop containing a self-complementary sequence of six residues. This structure is proposed to promote dimerization by loop-loop interaction and formation of a so-called 'kissing complex'. A 23-nucleotide RNA strand containing the loop enclosed by a seven base-pair stem has been synthesized. This oligomer was crystallized by the vapour-diffusion method at 310 K, pH 6.5, with methyl-pentanediol as the precipitant agent in the presence of MgCl2, KCl and spermine. Quasi-complete diffraction data were obtained at 2.7 A resolution with a conventional X-ray source and at 2.3 A resolution on a synchrotron beamline. The space group is P3121 or its enantiomorph P3221, with cell parameters a = b = 60. 1, c = 65.9 A at ambient temperature, or a = b = 59.0, c = 64.3 A in a nitrogen-gas stream. There are two oligomers per asymmetric unit as determined from absorbance measurements of a dissolved crystal whose volume was carefully determined. In some cases, either perfectly or partially twinned crystals were obtained. Perfect twinning is detected by an apparent hexagonal symmetry and yields unusable crystallographic data, whilst partial twinning yields usable data after adequate processing. Structure solution is under way by searching for heavy-atom derivatives and systematically substituting bromo- or iodo-uridines for uridines.

Phase II study of prolonged infusion of Taxol in patients with metastatic colorectal carcinoma

PURPOSE

Taxol represents a new class of anticancer agents with activity against a wide variety of solid tumors. In preclinical systems, its cytotoxicity is schedule dependent with prolonged exposure being more effective. We studied a 120-hour infusion schedule of Taxol in patients with metastatic measurable colorectal carcinoma who had had one prior 5-FU-based chemotherapy.

METHODS

Patients with measurable metastatic colorectal carcinoma were eligible. Patients had to have normal liver, renal, and bone marrow functions. Written informed consent was obtained from all patients. The starting dose of Taxol was 150 mg/m2 infused over 120-hours in the outpatient setting. Taxol was repeated every 21 days.

RESULTS

Fifteen patients were registered. Among 14 evaluable patients, we did not observe any complete or partial response. Major toxicity included myelosuppression and mucositis. There was no treatment-related death.

CONCLUSION

Taxol administered by this schedule was found ineffective in patients with metastatic colorectal carcinoma who had previously received one 5-FU-based chemotherapy.

Influence of the 'directions for use' on positivity rates of the Hemoccult II test

OBJECTIVE

A concise, detailed, and complete instruction sheet is indispensable for adequate completion by the users of a product. This sheet should be enclosed in the envelope which contains Hemoccult II slides. The authors found that the instructions provided by the French manufacturer were unsatisfactory. They designed a short and simple notice, adequately detailed to be understandable by all volunteers and to obtain satisfactory stool smears. Positivity rates of Hemoccult II performed with the manufacturer's notice were compared to those obtained with Hemoccult II performed with the authors' instructions.

METHODS

This study was made during the third screening campaign carried out by the Office Departemental de Lutte contre le Cancer (ODLC). This screening programme only concerned women 59 to 69 years of age. Six thousand three hundred and ninety-two Hemoccult II containing the manufacturer's instructions were received at the laboratory during March, April, May, June and July 1996, and 2633 Hemoccult II containing the ODLC instructions during March, April, May, June and July 1997. All Hemoccult II were developed and read by one trained technician in the Biochemistry Laboratory (Grenoble University Hospital).

RESULTS

The two populations, studied in 1996 and 1997, were strictly comparable in terms of age and number of previous screenings. Out of 6392 Hemoccult II containing the manufacturer's instructions, 157 (2.5%) were found positive, as compared to 36 (1.4%) Hemoccult II out of 2633 which contained the authors' instructions. This difference is highly significant (P = 0.001).

CONCLUSION

The directions for use provided with Hemoccult II had a crucial influence on positivity rates, and therefore on the cost of screening. The instruction sheet provided by the French manufacturer is not satisfactory as it contains too much needless information, while several important pieces of advice are missing.

[Peripheral neuropathies and chronic hepatitis C: a frequent association?]

OBJECTIVE

The aim of this prospective study was to evaluate the prevalence of the peripheral neuropathies associated with chronic hepatitis C and their clinical, electrophysiological and histological characteristics.

PATIENTS AND METHODS

Thirty six patients admitted from December 1994 to January 1996 for chronic hepatitis C were prospectively investigated. Laboratory data included liver blood tests, serum cryoprecipitate immunoelectrophoresis, assays for anti-nuclear antibody, rheumatoid factor, circulating immune complexes, anti-SSA and anti-SSB antibodies. For each patient, a clinical neurological evaluation as well as an electrophysiological evaluation were performed by the same operator. In presence of peripheral neuropathy, a neuromuscular biopsy was performed.

RESULTS

In seven patients (19%), a peripheral neuropathy was diagnosed related to hepatitis C virus in 3 patients. In these 3 patients presenting with leg paresthesia, an axonal sensitive neuropathy was evidenced by electromyography. A neuromuscular biopsy performed in two of these patients showed a severe diminution of the myelinated fibers associated with vasculitis lesions in one patient. A skin biopsy was performed in the third patient with leg purpura revealing a leukocytoclasic vasculitis. A positive cryoglobulinemia was found in two of these patients.

CONCLUSION

In chronic hepatitis C, the prevalence of peripheral neuropathy is 8% and usually associated with cryoglobulinemia. It is an axonal neuropathy with diminution of the myelinated fibers and vasculitis lesions in the absence of cryoglobulinemia.

All in the family: structural and evolutionary relationships among three modular proteins with diverse functions and variable assembly

The crystal structures of three proteins of diverse function and low sequence similarity were analyzed to evaluate structural and evolutionary relationships. The proteins include a bacterial bleomycin resistance protein, a bacterial extradiol dioxygenase, and human glyoxalase I. Structural comparisons, as well as phylogenetic analyses, strongly indicate that the modern family of proteins represented by these structures arose through a rich evolutionary history that includes multiple gene duplication and fusion events. These events appear to be historically shared in some cases, but parallel and historically independent in others. A significant early event is proposed to be the establishment of metal-binding in an oligomeric ancestor prior to the first gene fusion. Variations in the spatial arrangements of homologous modules are observed that are consistent with the structural principles of three-dimensional domain swapping, but in the unusual context of the formation of larger monomers from smaller dimers or tetramers. The comparisons support a general mechanism for metalloprotein evolution that exploits the symmetry of a homooligomeric protein to originate a metal binding site and relies upon the relaxation of symmetry, as enabled by gene duplication, to establish and refine specific functions.

[Acute intermittent porphyria associated with hyperaldosteronism and inappropriate antidiuretic hormone secretion syndrome]

Acute intermittent porphyria, the most commun acute porphyria in France, is an autosomal dominant disorder of heme biosynthesis. The basic biochemical defect is reduced activity of the enzyme porphobilinogen deaminase. Clinical evolution is characterized by acute attacks, with a severe prognosis due to acute abdominal pain and risk of neurological complications, induced by drug intake, infection, alcohol intake or unknown factors. We report the case of a patient with an inappropriate antidiuretic secretion syndrome and secondary hyperaldosteronism associated with acute intermittent porphyria and polyradiculoneuritis syndrome. This syndrome was found to be induced a delayed reaction to thiopental. A favorable response was achieved with heme-arginate treatment.

Phase II study of Taxol in patients with advanced gastric carcinoma

PURPOSE

Taxol (paclitaxel) represents a new class of anticancer agent with activity against a wide variety of solid tumors. It has been found to be active in patients with adenocarcinoma and squamous cell carcinoma of the esophagus. To determine its activity against gastric adenocarcinoma, we conducted a phase II trial of Taxol in chemotherapy-naive patients with advanced disease.

PATIENTS AND METHODS

Patients with measurable, unresectable, metastatic gastric carcinoma with performance status < or = 2 by Zubrod scale were eligible. Patients had to have normal liver, renal, and bone marrow functions. Written informed consent was obtained from all patients. The starting dose of Taxol was 200 mg/m2 infused over either 3 hours (in the first 15 patients) or 24 hours (in the subsequent 18 patients). Taxol was repeated every 21 days. Response was evaluated after two courses.

RESULTS

Thirty-three patients were registered. The median number of courses was two (range, 1 to 12; total, 112 courses). Thirty patients were evaluable for response and toxicity. Among the first 15 patients (two inevaluable) receiving Taxol over 3 hours, there were one partial response (PR) (one of 13 patients, or 8%; 95% confidence interval, 0% to 36%) and three minor responses (MRs). However, among the 18 patients (one inevaluable) receiving Taxol over 24 hours, there were four PRs (four of 17 patients or 23%; 95% confidence interval, 7% to 50%) and three MRs. The overall PR rate was 17% (five of 30 patients; 95% confidence interval, 6% to 35%). The median duration of PR was 6.5 months (range, 2.3 months to 11.3+ months. There were no treatment-related deaths. Myelosuppression was more severe with the 24-hour schedule than with the 3-hour schedule.

CONCLUSIONS

Taxol has a modest degree of activity against gastric carcinoma. It is well tolerated by the patients. Further studies of Taxol in combination with other active agents against gastric carcinoma should be considered.

One-month results of coronary stenting in patients > or = 75 years of age

Coronary artery bypass operations are associated with increased morbidity and mortality in the elderly. Similarly, it has been shown that coronary angioplasty is associated with a higher risk of complications in the elderly than in younger patients. The purpose of this study was to evaluate the 1-month outcome of elderly patients (>75 years old) who were included in the Stenting without Coumadin French Registry. From December 1992 to March 1995, 2,900 patients (mean age 61+/-11 years) were included in this registry. All patients were treated with ticlopidine (250 to 500 mg/day) for 1 month from the day of percutaneous transluminal angioplasty, aspirin (100 to 250 mg/day) for >6 months, and low-molecular-weight heparin (antiXa 0.5 to 1 IU/ml) for 1 month in phase II, 15 days in phase III, and 7 days in phase IV. No heparin was given in phase V. The study group included 233 patients (8.0%) > 75 years old (mean age 79+/-4), 44 (18%) of whom were women. All patients underwent dilatation of a native coronary vessel. One hundred seventeen had unstable angina (50.2%), 20 had postmyocardial infarction ischemia (8.6%), and 6 had acute myocardial infarction (2.6%). Indications for stenting were de novo lesion in 63 patients (27.0%), restenosis in 38 (16.3%), suboptimal result in 48 (20.6%), nonocclusive dissection in 56 (24.0%), and occlusive dissection in 28 (12.0%), respectively. Stented coronary arteries were the left anterior descending in 109 (46.8%), the right in 80 (34.3%), the left circumflex in 40 (17.2%), and the left main in 4 (1.7%). Palmaz-Schatz stents were used in 228 patients (82.0%), AVE microstents in 38 (13.7%), and other stents in 12 (4.3%). More than 1 stent was used in 48 patients (17.3%). The mean diameter of the balloon used for stenting was 3.31+/-0.38 mm and maximal inflation pressure was 12.2+/-2.9 atm. At one-month follow-up, vascular complications occurred in 5 patients, requiring surgery in 2 (1.3%), acute closure occurred in 1 (0.4%), subacute closure in 3 (1.3%), emergency or planned coronary artery bypass graft surgery in none, acute myocardial infarction in 4 (1.7%), stroke in 1 (0.4%), and death in 8 (3.4%). The composite end point of a major cardiac event was observed in 13 cases (5.6%). Coronary stenting using ticlopidine and aspirin appears to be a particularly safe approach in this high-risk subset.

Newborn and adult recombinant inbred strains: a tool to search for genetic determinants of target organ damage in hypertension

It has been proposed that one of the primary events in the development of essential hypertension is a growth-related process initiated as early as during fetal development. Differences in kidney size have been observed between most rat models of hypertension and their respective controls. In this study, we analyzed relative kidney size (kidney weight/body wt) in a set of rat recombinant inbred strains (RIS) (N = 27) and their progenitors, the spontaneously hypertensive rat strain (SHR/Ola) and Brown Norway congenic strain (BN.1x), at two different ages, at birth and at 15 weeks. In the progenitors, the relative kidney weight was higher in the hypertensive than in the normotensive strain of both the newborn (P < 0.001) and adult (P < 0.001) animals. In the RIS, a significant correlation was found between the newborn and adult relative kidney weight (r = 0.49, P = 0.01), indicating that the two phenotypes share some of their genetic determinants. A total genome search of newborn and adult relative kidney weight was performed with a total of 453 genetic markers. These analyses revealed several suggestive quantitative trait loci (QTL), some of which were, indeed, significant for both newborn and adult relative kidney weight (such as, D3Mit9 on rat chromosome 3; r = -0.50, P < 0.01; r = -0.47, P < 0.01; respectively). Others, such as the locus on rat chromosome 1 (Rt6; r = -0.43, P < 0.05), were significant only for the adult relative kidney size. This QTL was found in close proximity to a region previously related to susceptibility to hypertensive renal disease in the fawn-hooded rat and, similarly to that study, its effect was found to be independent of blood pressure. Furthermore, a growth pattern of the kidneys after birth, evaluated as the difference between the newborn and adult relative kidney weight, was also subjected to total genome scan. Several suggestive QTL were identified. One of the most significant loci was found at the D1a marker on rat chromosome 17 (r = -0.51, P < 0.01), which was previously related to the determination of adult heart weight in the RIS. In conclusion, the current study demonstrates the usefulness of RIS in studies of hypertension-related phenotypes, some of which are abnormal before the development of high blood pressure. To better understand their role in the pathogenesis of hypertension, studies at different ages are needed, which are uniquely feasible in RIS.

Stenting in acute myocardial infarction

The limitations (recurrent ischaemia, restenosis, reocclusion) of percutaneous transluminal coronary angioplasty (PTCA) in acute myocardial infarction (MI) can be addressed by stenting. The preliminary results of stenting are favourable (Stent PAMI, STENTIM, ZWOLLE trials). We report the results of the ICPS registry including 519 patients directly treated with angioplasty and stenting at the acute phase of myocardial infarction, with a repeat MI rate of 1% and a mortality of 3.7% in the non-shock group.

Highly resolved chemical imaging of living cells by using synchrotron infrared microspectrometry

Using synchrotron radiation as an ultra-bright infrared source, we have been able to map the distributions of functional groups such as proteins, lipids, and nucleic acids inside a single living cell with a spatial resolution of a few microns. In particular, we have mapped the changes in the lipid and protein distributions in both the final stages of cell division and also during necrosis.

Chemical imaging of nucleic acids, proteins and lipids of a single living cell. Application of synchrotron infrared microspectrometry in cell biology

Hybridoma B-cells have been used as models to evaluate the performance of synchrotron infrared microscopy to obtain chemical images of a single living cell. Chemical mapping of nucleic acids, proteins and lipids at a resolution of a few microns, close to the diffraction limit in the mid-infrared region are shown.

Recurrent intracerebral hemorrhage

Between 1984 and 1994, of the 375 patients admitted to our department for intracerebral hemorrhage (ICH), 24 (6.4%) had a recurrent ICH. There were 15 women and nine men and the mean age of the patients was 64.7 +/- 9.4 years (range 49-81) at the first bleeding episode and 68.7 +/- 7.5 years (range 57-83) at the second. The mean interval between the two bleeding episodes was 47.5 +/- 30.5 months (range 3 months to 14.8 years). Nine patients presented with more than one recurrence of ICH. Seventy-one percent of the patients were hypertensive. The site of the first hemorrhage was lobar in 17 patients, ganglionic (putamen, thalamus, or caudate nucleus) in six patients, and subdural in one. The recurrent hemorrhage occurred at a different location from the previous ICH. The most common pattern of recurrence was "lobar-lobar" (14 patients) and more rarely "ganglionic-ganglionic" (five patients), which was always observed in hypertensive patients. The outcome after the recurrent hemorrhage was usually poor, with severe cognitive impairment. By comparison with 81 patients followed up to 24 months (47.9 +/- 22.2 months) with isolated ICH without recurrence, only lobar hematoma and a younger age were risk factors for recurrences whereas sex and previous hypertension were not. The mechanisms of recurrence of ICH were multiple (hypertension, cerebral amyloid angiopathy). Control of blood pressure after the first hemorrhage may prevent ICH recurrences.