Poly(glutamic acid) for biomedical applications

Paclitaxel is a widely used anti-cancer agent. Conjugates of paclitaxel with poly(glutamic acid) have shown great promise in preclinical trials, and clinical trials are now underway. Preclinical data suggest that more paclitaxel is preferentially delivered to tumor sites vs. nonconjugated paclitaxel. When poly(glutamic acid) is conjugated to other families of cancer drugs, similar improvements in effectiveness and reduced toxicity are observed. Optimization of poly(glutamic acid) for use in drug delivery applications is a key step in making this technology viable.

Gender differences in neonatal subcutaneous fat store in late gestation in relation to maternal weight gain

OBJECTIVE

To study gender differences in fat store in human newborns and their relation to duration of gestation and maternal weight gain.

METHODS

The ratios subscapular skinfold thickness/body weight (SST/BW) and tricipital skinfold thickness/body weight (TST/BW) were calculated in a sample of 13609 premature and term neonates from the maternity hospital of Clamart, Hauts-de-Seine, France.

RESULTS

Whereas BW, SST and TST increased with gestational age, SST/BW and TST/BW ratios decreased regularly, in males as in females. This result reflects a progressive reduction of subcutaneous fat store per body weight unit as the duration of gestation increases. Males had smaller values of SST/BW and TST/BW ratios than females whatever the gestational age. Increasing maternal weight gain during the third gestational trimester did not improve the subcutaneous fatness per body weight unit of the newborn. Earlier amount of maternal weight gain had an effect on the TST/BW index exclusively in females.

CONCLUSIONS

In newborns, a gender difference was observed in the ratio of subcutaneous fat per unit of body weight; this ratio is lower in males than in females. This result argues for a gender difference in mobilization of fat store to ensure normal growth in the last weeks of pregnancy: males lose more fat but gain more weight than females in this period. Late maternal weight gain does not affect the proportion of subcutaneous fatness by body weight unit in both genders.

[CagA status and virulence of Helicobacter pylori strains. Results of a French multicentric prospective study]

Previous experimental and epidemiological studies with few patients suggested that the presence of the cagA gene was a virulence factor for Helicobacter pylori (H. pylori).

AIM

To establish in this large epidemiological cohort study the relationship between the histological virulence of H. pylori infection and the cagA status of the bacteria.

METHODS

This prospective cohort study (6 month follow-up) was conducted on adult patients undergoing endoscopy for upper gastrointestinal symptoms. The cagA status of H. pylori-positive patients was established using the polymerase chain reaction (PCR) method on an antral biopsy. A score of histological virulence (inflammation, activity) was recorded on the basis of the Sydney system (on antral, angular and fundic biopsies). Eradication treatment given was not imposed and a clinical follow-up was performed at 3 and 6 months. H. pylori eradication was verified by a 13C urea breath test at 3 months.

RESULTS

Four hundred and twenty two centers recruited 652 patients (mean age: 51 +/- 15 years, 55% female). Upper GI endoscopy was abnormal in 80% of the patients of whom 68% had a gastritis aspect; 38% were infected by H. pylori, and among them 51% were cagA-positive. The histological virulence scores associated with the cagA-positive strains were significantly higher than those associated with the cagA-negative strains, globally (P = 0.0035), in the antrum (P = 0.0063), and in the angulus (P = 0.046), but not in the fundus (P = 0.05). The cagA status was correlated neither with the symptom severity at inclusion and at 6 months (P > 0.05), nor with the H. pylori eradication rate at 3 months (75% in cagA-positive and 70% in cagA-negative strains, P = 0.52).

CONCLUSION

This study on a large cohort of patients confirms the greater histological virulence of H. pylori cagA-positive strains. However, this virulence was not associated with more severe symptoms nor with an increase in resistance to H. pylori eradication treatment.

[Quality of life of lumbago patients cared for in a pain center]

OBJECTIVE

To evaluate the quality of life of patients treated in a pain center.

METHOD

Sixty eight patients were assessed during their first consultation, then 6, 12 and 18 months later, using a quality of life questionnaire "SQVP or Subjective Quality of Life Profile" validated in French populations and a panel of questionnaires for the monitoring of chronic pain, recommended by the ANAES (French Agency for Health Assessment).

RESULTS

Results showed that: the patients' quality of life was clearly deteriorated (lowest quality in the data base--14,000 patients--with regard to the SQVP); the profile obtained (severe handicap) suggests that the lumbagos are part of a psychiatric context; the patients' quality of life clearly improves after 6 months' treatment, but the pain only stabilizes later.

Mechanisms of uptake and resistance to troxacitabine, a novel deoxycytidine nucleoside analogue, in human leukemic and solid tumor cell lines

Troxacitabine (Troxatyl; BCH-4556; (-)-2'-deoxy-3'-oxacytidine), a deoxycytidine analogue with an unusual dioxolane structure and nonnatural L-configuration, has potent antitumor activity in animal models and is in clinical trials against human malignancies. The current work was undertaken to identify potential biochemical mechanisms of resistance to troxacitabine and to determine whether there are differences in resistance mechanisms between troxacitabine, gemcitabine, and cytarabine in human leukemic and solid tumor cell lines. The CCRF-CEM leukemia cell line was highly sensitive to the antiproliferative effects of troxacitabine, gemcitabine, and cytarabine with inhibition of proliferation by 50% observed at 160, 20, and 10 nM, respectively, whereas a deoxycytidine kinase (dCK)-deficient variant (CEM/dCK(-)) was resistant to all three drugs. In contrast, a nucleoside transport-deficient variant (CEM/ARAC8C) exhibited high levels of resistance to cytarabine (1150-fold) and gemcitabine (432-fold) but only minimal resistance to troxacitabine (7-fold). Analysis of troxacitabine transportability by the five molecularly characterized human nucleoside transporters [human equilibrative nucleoside transporters 1 and 2, human concentrative nucleoside transporter (hCNT) 1, hCNT2, and hCNT3] revealed that short- and long-term uptake of 10-30 microM [(3)H]troxacitabine was low and unaffected by the presence of either nucleoside transport inhibitors or high concentrations of nonradioactive troxacitabine. These results, which suggested that the major route of cellular uptake of troxacitabine was passive diffusion, demonstrated that deficiencies in nucleoside transport were unlikely to impart resistance to troxacitabine. A troxacitabine-resistant prostate cancer subline (DU145(R); 6300-fold) that exhibited reduced uptake of troxacitabine was cross-resistant to both gemcitabine (350-fold) and cytarabine (300-fold). dCK activity toward deoxycytidine in DU145(R) cell lysates was <20% of that in DU145 cell lysates, and no activity was detected toward troxacitabine. Sequence analysis of cDNAs encoding dCK revealed a mutation of a highly conserved amino acid (Trp(92)-->Leu) in DU145(R) dCK, providing a possible explanation for the reduced phosphorylation of troxacitabine in DU145(R) lysates. Reduced deamination of deoxycytidine was also observed in DU145(R) relative to DU145 cells, and this may have contributed to the overall resistance phenotype. These results, which demonstrated a different resistance profile for troxacitabine, gemcitabine, and cytarabine, suggest that troxacitabine may have an advantage over gemcitabine and cytarabine in human malignancies that lack or have low nucleoside transport activities.

Genetic polymorphisms of the renin-angiotensin-aldosterone system in end-stage renal disease

BACKGROUND

Hypertension contributes to the progression to renal failure. A genetic susceptibility to hypertension may predispose to the development of end-stage renal disease (ESRD) and promote a more rapid progression to ESRD in patients with renal diseases. Genes encoding for angiotensinogen (AGT), angiotensin-converting enzyme (ACE), and aldosterone synthase (CYP11B2) are candidates for abnormal blood pressure regulation.

METHODS

Genotyping was performed in 327 control subjects and 260 ESRD patients for the M235T-AGT, the insertion/deletion (I/D)-ACE, and the -344T/C-CYP11B2 gene polymorphisms using polymerase chain reaction, gel analysis, and appropriate restriction digest when required.

RESULTS

Genotype frequencies did not differ significantly between ESRD patients and controls. When ESRD diabetic subjects were compared with diabetic patients without nephropathy, the prevalence of the AGT-MM genotype was lower (28.1 vs. 52.8%, P < 0.01), while the AGT-TT genotype was higher (15.6 vs. 2.7%, P < 0.05). The AGT-TT genotype was associated with a faster progression to ESRD in patients with glomerulonephritis (P < 0.05). In the total ESRD population, progression of renal disease was faster with the ACE-DD than with the DI and II alleles (P < 0.05). This association was particularly strong when the interaction with the AGT genotype was analyzed, with a rapid progression in ACE-DD as compared with ACE-DI and II in patients with the AGT-MM genotype (P < 0.01).

CONCLUSIONS

Susceptibility for ESRD and faster progression to ESRD are linked with the AGT genotype in diabetic patients. Faster progression to ESRD is associated with the ACE genotype when the total population with ESRD and with the AGT genotype when patients with glomerulonephritis are considered. Thus, genes of the renin-angiotensin-aldosterone system are candidate genes for further understanding of the interindividual differences in the development and course of ESRD.

Topically applied vitamin C enhances the mRNA level of collagens I and III, their processing enzymes and tissue inhibitor of matrix metalloproteinase 1 in the human dermis

Ascorbic acid (vitamin C) is a cofactor required for the function of several hydroxylases and monooxygenases. It is not synthesized in humans and some other animal species and has to be provided by diet or pharmacologic means. Its absence is responsible for scurvy, a condition related in its initial phases to a defective synthesis of collagen by the reduced function of prolylhydroxylase and production of collagen polypeptides lacking hydroxyproline, therefore, they are unable to assemble into stable triple-helical collagen molecules. In fibroblast cultures, vitamin C also stimulates collagen production by increasing the steady-state level of mRNA of collagen types I and III through enhanced transcription and prolonged half-life of the transcripts. The aim of the experimental work has been to evaluate the effect on dermal cells of a preparation of vitamin C topically applied on one side vs placebo on the other side of the dorsal face of the upper forearm of postmenopausal women. Biopsies were collected on both sides and the level of mRNA measured by non competitive reverse transcription-polymerase chain reaction made quantitative by the simultaneous transcription and amplification of synthetic RNA used as internal standards. The mRNA of collagen type I and type III were increased to a similar extent by vitamin C and that of three post-translational enzymes, the carboxy- and amino-procollagen proteinases and lysyloxidase similarly increased. The mRNA of decorin was also stimulated, but elastin, and fibrillin 1 and 2 were not modified by the vitamin. The expression of matrix metalloproteinases 1, 2, and 9 was not significantly changed, but an increased level of tissue inhibitor of matrix metalloproteinase 1 mRNA was observed without modification of tissue inhibitor of matrix metalloproteinase 2 mRNA. The stimulating activity of topical vitamin C was most conspicuous in the women with the lowest dietary intake of the vitamin and unrelated to the level of actinic damage. The results indicate that the functional activity of the dermal cells is not maximal in postmenopausal women and can be increased.

Diet profiles in a population sample from Mediterranean southern France

OBJECTIVE

A Mediterranean diet quality index (MDQI) was devised to give an overall assessment of dietary habits and to identify groups at risk.

DESIGN

The MDQI was based on scores given for selected levels of consumption of selected nutrients and foods.

SETTING

Mediterranean southern France.

SUBJECTS

The sample included 473 men and 491 women in three age classes recruited at random.

RESULTS

Only 9.5% of men, 9.0% of women, 4.7% of 20-34 year old subjects, 6.6% of 35-54 year old subjects and 14.0% of 55-76 year old subjects were shown to have a healthy diet. However, 10.1% of men, 8.6% of women, 19.4% of 20-34 year old subjects, 10.2% of 35-54 year old subjects and 4.6% of 55-76 year old subjects were shown to have a poor diet. There were significantly fewer smokers among subjects with a good diet but the distribution of moderate wine drinkers was comparable between those with a good diet and those with a poor diet. Correspondence analysis associated a healthy diet with 55-76 year old men and women living in rural areas, who had received primary schooling only and who were manual workers. Both men and women with a poor MDQI score tended to be young and smokers. In addition, women with a poor MDQI tended to be heavy drinkers and obese.

CONCLUSIONS

This study showed that the Mediterranean model, which is generally recognized as a healthy diet, appears restricted to older people and to rural areas, whereas urbanized young people depart from it. A nutritional prevention policy targeted at young adults is required to encourage them to adhere to the Mediterranean model. Smoking and drinking showed different distribution patterns in the sample under study.

[Mothers' behavior regarding infant sleep position: effects of the last public campaign to prevent sudden infant death syndrome]

BACKGROUND

To define infant care practices in maternity units and those subsequently adopted at home. Using these data, we evaluated the acceptance and application of recommendations issued by the previous public education campaign on infant sleeping position as related to sudden infant death syndrome.

PATIENTS AND METHODS

A survey was carried out in two maternity units (Port-Royal and Créteil) and in one pediatric consultation unit (affiliated with Port-Royal maternity).

RESULTS

The mixed position (side or back) is used equally with, respectively, 47% at Port-Royal and 45% at Créteil. The supine sleeping position (French public health recommendations) is used by 12% of the mothers at Port-Royal and by 40% at Créteil. It appears that hospital nurseries play an important role in determining the mother's preference for the sleeping position (64% at Port-Royal and 54% at Créteil), but it does not adequately explain all mothers' responses. However, as the infants mature (> two months old), the more spontaneously they changed their sleeping position. All the infants placed in a side sleeping position moved to a supine sleeping position during the night. Upon awakening, infants were found mostly in the supine position (in contrast to the national public education campaign).

CONCLUSION

Our results show that mothers and hospital nurseries were distressed in terms of ensuring the supine sleeping position of the infant. New choices of sleeping positions were initiated by mothers. For example, they used the side position after feedings essentially in the case of reflux or during the daytime. The supine position was used when the mothers were assured that any problems had been avoided or only during the night.

[Multidisciplinary treatment of neurologic pain and indications for antalgic surgery]

We present our multidisciplinary approach systematically adopted for patients with resistant pain. All the anatomic, pathophysiological, clinical, radiographical, electrophysiological and psychological aspects of pain should be considered before deciding on treatment indication. These principles are illustrated by a description of different available medical and surgical techniques for the treatment of paraplegic pain. We emphasize the importance of pain centers in caring for these patients. All possibilities for antalgic treatment can be considered in such centers, providing a better approach to all aspects of pain.

The practice of structure activity relationships (SAR) in toxicology

Both qualitative and quantitative modeling methods relating chemical structure to biological activity, called structure-activity relationship analyses or SAR, are applied to the prediction and characterization of chemical toxicity. This minireview will discuss some generic issues and modeling approaches that are tailored to problems in toxicology. Different approaches to, and some facets and limitations of the practice and science of, SAR as they pertain to current toxicology analyses, and the basic elements of SAR and SAR-model development and prediction systems are discussed. Other topics include application of 3-D SAR to understanding of the propensity of chemicals to cause endocrine disruption, and the use of models to analyze biological activity of metal ions in toxicology. An example of integration of knowledge pertaining to mechanisms into an expert system for prediction of skin sensitization to chemicals is also discussed. This minireview will consider the utility of modeling approaches as one component for better integration of physicochemical and biological properties into risk assessment, and also consider the potential for both environmental and human health effects of chemicals and their interactions.

Epidemiology of recurrences or reinfections of Clostridium difficile-associated diarrhea

Approximately 15 to 35% of patients with a first episode of Clostridium difficile-associated diarrhea relapse within 2 months. Between 1994 and 1997, strains from 93 hospitalized patients with C. difficile recurrences were fingerprinted by using both serotyping and PCR-ribotyping. The results showed that 48.4% of clinical recurrences were, in fact, reinfections with a different strain of C. difficile. Rates of clinical recurrences could therefore be reduced by implementing strict isolation precautions.

Epidemiology of recurrences or reinfections of Clostridium difficile-associated diarrhea

Approximately 15 to 35% of patients with a first episode of Clostridium difficile-associated diarrhea relapse within 2 months. Between 1994 and 1997, strains from 93 hospitalized patients with C. difficile recurrences were fingerprinted by using both serotyping and PCR-ribotyping. The results showed that 48.4% of clinical recurrences were, in fact, reinfections with a different strain of C. difficile. Rates of clinical recurrences could therefore be reduced by implementing strict isolation precautions.

Parietal and cingulate processes in central pain. A combined positron emission tomography (PET) and functional magnetic resonance imaging (fMRI) study of an unusual case

Parietal, insular and anterior cingulate cortices are involved in the processing of noxious inputs and genesis of pain sensation. Parietal lesions may generate central pain by mechanisms generally assumed to involve the 'medial' pain system (i.e. medial thalamic nuclei and anterior cingulate cortex (ACC)). We report here PET and fMRI data in a patient who developed central pain and allodynia in her left side after a bifocal infarct involving both the right parietal cortex (SI and SII) and the right ACC (Brodmann areas 24 and 32), thus questioning the schematic representation of cortical pain processing. No rCBF increase was found in any part of the residual cingulate cortices, neither in the basal state (which included spontaneous pain and extended hypoperfusion around the infarct), nor during left allodynic pain. Thus, as previously observed in patients with lateral medullary infarct, neither spontaneous pain nor allodynia reproduce the cingulate activation observed after noxious pain in normal subjects. Conversely, both PET and fMRI data argue in favour of plastic changes in the 'lateral discriminative' pain system. Particularly, allodynia was associated with increased activity anteriorly to the infarct in the right insula/SII cortex. This response is likely to be responsible for the strange and very unpleasant allodynic sensation elicited on the left side by a non-noxious stimulation.

Optical contrast in apertureless microscopy

We report on optical image contrast for a specific apertureless near-field optical microscope. We demonstrate that the main part of the optical image's contrast results from the sample's topography. The coupling mechanism is analyzed, and we show that the microscope can be regarded as an interferometer that sensitively detects near-field components. However, in the basic configuration the reference field of the interferometer is coupled to the topography. Finally, it is demonstrated that, by controlling the phase of the reference field, one can largely decorrelate the optical image from the topography.

[Epidemiology of gastro-esophageal-reflux in general practice. . Predictive factors for health care utilization in the course of a year]

AIM

To assess the epidemiology and course of GORD, treatment demand, and factors predictive of GORD course in a 1-year study in patients with heartburn consulting general practitioners.

METHODS

A total of 984 patients with pyrosis were included by general practitioners. After the initial visit, they had follow up at 3, 6 and 12 months by phone contact.

RESULTS

Most patients (87%) had been suffering from heartburn for 4+/-1.5 years; upper GI endoscopy had been performed in 63% of patients. Patients evaluated the symptoms of the current episode as mild (6%), moderate (60%), or severe/incapacitating (34%). During the year of follow up, 12% of the patients were free of heartburn; the mean number of consultations with general practitioners and gastroenterologists was 5.1 and 0.5 respectively. At day 90, discomfort due to heartburn was absent in 4% of patients, slight in 51%, moderate in 32%, and severe in 6%. At day 360, predictive factors for discomfort were: discomfort related to heartburn on D90, the length of time the patients had been suffering from GORD, and the main reason for consultation on D1; patients for whom heartburn was not the main reason for consultation on D1 experienced a higher level of discomfort. The predictive factors for the extent of treatment demand over 12 months were: age, discomfort related to heartburn on D90, severity on D1, the frequency of episodes prior to the episode on D1 and the levels of stress and anxiety measured on D1.

CONCLUSIONS

Epidemiologic characteristics of patients with heartburn consulting a general practitioner were different from these of the general population. Treatment demand depends both on severity of heartburn and level of stress and anxiety.