Brittle-quasibrittle transition in dynamic fracture: an energetic signature

Dynamic fracture experiments were performed in polymethylmethacrylate over a wide range of velocities and reveal that the fracture energy exhibits an abrupt threefold increase from its value at crack initiation at a well-defined critical velocity, below the one associated with the onset of microbranching instability. This transition is associated with the appearance of conics patterns on fracture surfaces that, in many materials, are the signature of damage spreading through the nucleation and growth of microcracks. A simple model allows us to relate both the energetic and fractographic measurements. These results suggest that dynamic fracture at low velocities in amorphous materials is controlled by the brittle-quasibrittle transition studied here.

Phase II study on paclitaxel in patients with recurrent, metastatic or locally advanced vulvar cancer not amenable to surgery or radiotherapy: a study of the EORTC-GCG (European Organisation for Research and Treatment of Cancer--Gynaecological Cancer Group)

BACKGROUND

No standard treatment options are available for patients with advanced, recurrent or metastatic vulvar carcinoma not amenable for locoregional treatment.

PATIENTS AND METHODS

In this phase II study, patients with advanced vulvar cancer received paclitaxel (Taxol) every 3 weeks for up to 10 cycles. Primary objective was response rate. Secondary objectives were response duration and toxicity. Response evaluation was assessed by World Health Organisation criteria, toxicity according to Common Toxicity Criteria.

RESULTS

Thirty-one women from 10 institutions were included, with a median age of 64 (range 47-84), of which 29 were assessable for response. On study patients received a median of four cycles (range 1-10).

SAFETY

Grade 3 and 4 neutropenia was seen in eight patients (8/29 = 27.6%), which in one patient resulted in neutropenic fever and treatment-related death. Further treatment-related grade 3/4 toxicity includes fatigue in three patients (10.3%) and neuropathy in one patient (3.4%).

EFFICACY

Overall response was 13.8% (n = 4; two complete responses + two partial responses). With a median follow-up of 24 months, median PFS was 2.6 months (95%confidence interval 2.04-4.21).

CONCLUSION

Paclitaxel shows moderate activity for local control in advanced vulvar cancer.

Germline expression of H-Ras(G12V) causes neurological deficits associated to Costello syndrome

Costello syndrome (CS) is a rare congenital disorder caused by germline activation of H-Ras oncogenes. A mouse model of CS generated by introduction of an oncogenic Gly12Val mutation in the mouse H-Ras locus using homologous recombination in embryonic stem (ES) cells has been recently described. These mice phenocopied some of the abnormalities observed in patients with CS, including facial dysmorphia and cardiomyopathies. We investigated here their neurological and behavioral phenotype. The analysis of H-Ras(G12V) mice revealed phenotypes that resembled the hyperemotivity, hypersensibility and cognitive impairments observed in children with CS. Stronger neurological deficits were found in the analysis of mice homozygous for this mutation than in the analysis of heterozygous mice, suggesting the existence of a gene dose effect. These mice represent the first mouse model for CS, offering an experimental tool to study the molecular and physiological alterations underlying the neurological manifestations of CS and to test new therapies aimed at preventing or ameliorating the cognitive and emotional impairments associated to this condition.

Determinants of coronary artery calcification progression in renal transplant recipients

Coronary artery calcification (CAC) is associated with increased atherosclerotic burden and cardiovascular events. The objective of this study was to determine the natural history and risk factors associated with CAC progression in a cohort of incident asymptomatic renal transplant recipients with no history of coronary revascularization. Electron-beam computed tomography was performed in 82 subjects at time of transplantation and at least 1 year later. Mean (SD) and median CAC score increased for all subjects from 392.4 (747.9) and 75.8 at time of transplant to 475.3 (873.5), (p = 0.002[log]) and 98.9 (p < 0.001), respectively. Most subjects (89%) with no calcifications remained without calcification. Mean annualized rate (SD) of CAC score change was 52.5 (150) with a median of 0.5. Average yearly percent change was 67.3 (409.6) with a median of 1.4. In multivariate analysis, diastolic blood pressure at 3 months post-transplant, Caucasian race, glomerular filtration rate at 3.0, months post-transplant, body mass index and baseline CAC score were independent predictors of annualized rate of CAC change. There is significant progression of CAC post-renal transplantation in most subjects. Progression is most likely to occur in white patients and is associated with clinical factors such as blood pressure, body mass index, renal function and baseline CAC score.

Medical ethnobotany of the Teribes of Bocas del Toro, Panama

Ethnomedical uses of 108 medicinal plant species, belonging to 52 families, 89 genera, used by the Teribe Amerindians of Bocas del Toro Province in Panama, along with their socio-cultural practices are reported here. The methods of administration of the herbal remedies, the plant parts used, their families and local names are also documented. The recorded medicinal plants were used mainly for fever, various type of pain and inflammation. The potential value of 26 plants and their traditional uses was elucidated through literature search.

Decay of sperm obtained from epididymes of wild ruminants depending on postmortem time

We have carried out a study on the effect of postmortem time (PT) in some characteristics of epididymal sperm salvaged from hunted Iberian red deer and roe deer. Testis were collected, identified, refrigerated down to 5 degrees C, and sent to our laboratory by the wardens of the hunting reserves. This way, samples were delivered at different times postmortem. Sperm were extracted from the cauda epididymis by means of cuts. Analyzed parameters were: osmolality, pH, motility-both subjectively and with CASA, HOS test reactivity, acrosomal status and viability (assessed with propidium iodide). Osmolality and pH rose with prolonged postmortem time, possibly due to tissue decomposition. Most sperm quality parameters negatively correlated with PT. Besides, when comparing PT classes (groups of 24 h for red deer and 30 h for roe deer), we could appreciate that motility was more affected by PT than other quality variables. Progressive motility was especially impaired. We also classified the samples in high, medium and low quality for each PT group (considering progressive motility, intact acrosomes and reactivity to the HOS test), and it was clear that after 2 days the number of high quality samples was testimonial, and after several days, we almost found only low quality samples. In conclusion, epididymal sperm from Iberian red deer and roe deer undergo a decrease of quality with PT, but it could stay acceptable within many hours postmortem. There are implications for wildlife conservation programs, as epididymal sperm is a good source of germplasm. If valuable animals die and it is not possible to process their sperm immediately, it may still be possible to obtain viable spermatozoa many hours later.

Are dyspepsia management guidelines coherent with primary care practice?

BACKGROUND

Spontaneous physician behaviour can affect guideline applicability, implementation strategies and application costs, particularly in relation to widespread pathologies chiefly managed by general practitioners (GPs). Of the array of dyspepsia management guidelines, the closest to general practice, partly owing to proposing committee composition, are the European Society for Primary Care Gastroenterology (ESPCG) guidelines.

METHODS

To evaluate variability in dyspepsia management among GPs in Padua and divergence in spontaneous prescriptive behaviour from the ESPCG dyspepsia guideline, we prospectively studied the behaviour of 39 GPs over a 3-month period of outpatient activity, through questionnaires on each consultation. Test-group representativeness was preliminarily defined in terms of antisecretory drug expenditure.

RESULTS

1790 forms on dyspepsia-related consultations were studied in a population of 51,193 registered patients; 1264 patients with a history of dyspeptic pathology consulted their GP (19% duodenal ulcer (DU), 9% gastric ulcer (GU), 54% gastro-oesophageal reflux disease (GERD), 32% non-ulcer dyspepsia (NUD), 1% cholelithiasis), while 526 patients presented with symptoms of dyspepsia with no previous gastroscopy (EGDS) (42% were aged <45 years), of whom 42% had twice consulted their GP. Empirical management by prescription of symptomatic drugs was the most common procedure in DU (33%), GU (73%) and NUD (74%) relapses. Helicobacter pylori eradication therapy was prescribed in only 2% of patients with a history of organic or functional dyspepsia. 145 patients with uninvestigated dyspepsia were referred for second-level endoscopy and 43 for H. pylori testing. Forty-four percent of endoscopies prescribed for uninvestigated patients did not comply with the ESPCG guideline; full compliance would have determined a 105% rise in endoscopies. Prescriptive variability between GPs was high (based on the Goodman-Kruskal (0.41, P < 0.001) and Cramer tests (V = 0.51, P < 0.005)) and agreement between observed and expected prescriptions according to ESPCG criteria was as low as V = 0.11. On the basis of the most frequently observed behaviours, we developed three options of the ESPCG guideline and compared them to spontaneous prescriptions.

CONCLUSIONS

Highest compliance emerged where the clinical approach for all patients with uninvestigated dyspepsia was symptomatic therapy at first presentation followed by a different attitude at second presentation, setting a higher cut-off age than in the guideline (which in our case proved, on mathematical calculation, to be 55 years).

Brown adipose tissue-specific insulin receptor knockout shows diabetic phenotype without insulin resistance

Although insulin regulates metabolism in both brown and white adipocytes, the role of these tissues in energy storage and utilization is quite different. Recombination technology using the Cre-loxP approach allows inactivation of the insulin receptor in a tissue-specific manner. Mice lacking insulin receptors in brown adipocytes show an age-dependent loss of interscapular brown fat but increased expression of uncoupling protein-1 and -2. In parallel, these mice develop an insulin-secretion defect resulting in a progressive glucose intolerance, without insulin resistance. This model provides direct evidence for not only a role for the insulin receptors in brown fat adipogenesis, the data also suggest a novel role of brown adipose tissue in the regulation of insulin secretion and glucose homeostasis.

A regulatory light chain of ciliary outer arm dynein in Tetrahymena thermophila

Ciliary beat frequency is primarily regulated by outer arm dyneins (22 S dynein). Chilcote and Johnson (Chilcote, T. J., and Johnson, K. A. (1990) J. Biol. Chem. 256, 17257-17266) previously studied isolated Tetrahymena 22 S dynein, identifying a protein p34, which showed cAMP-dependent phosphorylation. Here, we characterize the molecular biochemistry of p34 further, demonstrating that it is the functional ortholog of the 22 S dynein regulatory light chain, p29, in Paramecium. p34, thiophosphorylated in isolated axonemes in the presence of cAMP, co-purified with 22 S dynein and not with inner arm dynein (14 S dynein). Isolated 22 S dynein containing phosphorylated p34 showed approximately 70% increase in in vitro microtubule translocation velocity compared with its unphosphorylated counterpart. Extracted p34 rebound to isolated 22 S dynein from either Tetrahymena or Paramecium but not to 14 S dynein from either ciliate. Binding of radiolabeled p34 to 22 S dynein was competitive with p29. Phosphorylated p34 was not present in axonemes isolated from a mutant lacking outer arms. Two-dimensional gel electrophoresis followed by phosphorimaging revealed at least five phosphorylated p34-related spots, consistent with multiple phosphorylation sites in p34 or perhaps multiple isoforms of p34. These new features suggest that a class of outer arm dynein light chains including p34 regulates microtubule sliding velocity and consequently ciliary beat frequency through phosphorylation.

Effects of local bupivacaine instillation on pain after laparoscopy

STUDY OBJECTIVE

To evaluate the effect of preincisional and intraperitoneal bupivacaine administration on immediate and late pain after operative laparoscopy.

DESIGN

Randomized study (Canadian Task Force classification I).

SETTING

University teaching hospital.

PATIENTS

One hundred fifty women undergoing laparoscopy for various gynecologic indications.

INTERVENTION

A dose of 0.5% bupivacaine 10 ml (50 mg) was injected into cannula sites before incisions and another 10 ml diluted with 100 ml saline into the peritoneal cavity at completion of the procedure. Equal amount of physiologic saline was used in controls.

MEASUREMENTS AND MAIN RESULTS

Modified McGill pain intensity scores and amount of analgesic required in the recovery room and within 24 hours postoperatively were evaluated. Of 150 women, 142 completed the study (71 bupivacaine group, 71 controls). Groups did not differ significantly in body mass index, duration of surgery, return to consciousness, and analgesic requirement during 3-hour observation in the recovery room and 24 hours after discharge. Pain scores were highest 30 minutes after the procedure in both groups. At that time the pain score in the bupivacaine group was lower than that in the control group (1.8 +/- 0.2 vs 2.3 +/- 0.2, p <0.05). Beyond that time, the groups did not differ in pain scores and analgesic requirements.

CONCLUSION

Postoperative pain is the highest within 30 minutes after laparoscopy. Local instillation of bupivacaine before incision and intraperitoneally was effective in reducing pain immediately after operative laparoscopy, but the effect was not seen beyond 30 minutes.

Synergistic gene interactions control the induction of the mitochondrial uncoupling protein (Ucp1) gene in white fat tissue

Among a selected group of mouse strains susceptible to dietary obesity, those with an enhanced capacity for Ucp1 and brown adipocyte induction in white fat preferentially lost body weight following adrenergic stimulation. Based on the generality of this mechanism for reducing obesity, a genetic analysis was initiated to identify genes that control brown adipocyte induction in white fat depots in mice. Quantitative trait locus (QTL) analysis was performed using the variations of retroperitoneal fat Ucp1 mRNA expression in progeny of genetic crosses between the A/J and C57BL/6J parental strains and selected AXB recombinant inbred strains. Three A/J-derived loci on chromosomes 2, 3, and 8 and one C57BL/6J locus on chromosome 19 were linked to Ucp1 induction in retroperitoneal fat. Although A/J-derived alleles seemed to contribute to elevated Ucp1 expression, the C57BL/6J allele on chromosome 19 increased Ucp1 mRNA to levels higher than parental values. Thus, novel patterns of C57BL/6J and A/J recombinant genotypes among the four mapped loci resulted in a transgressive variation of Ucp1 phenotypes. Although the extent of the interchromosomal interactions have not been fully explored, strong synergistic interactions occur between a C57BL/6J allele on chromosome 19 and an A/J allele on chromosome 8. In addition to selective synergistic interactions between loci, variations in recessive and dominant effects also contribute to the final levels of Ucp1 expression.

Beliefs about breast cancer risk and use of postmenopausal hormone replacement therapy

BACKGROUND

Postmenopausal hormone replacement therapy (HRT) decreases the risks of coronary heart disease and osteoporosis, but increases the risk of breast cancer. Although only 20-30% of postmenopausal women in the United States take HRT, the relationship between breast cancer risk perception and use of HRT is not known.

OBJECTIVE

To assess the impact of belief that HRT increases breast cancer risk and high perceived risk of breast cancer on the use of HRT.

DESIGN

Cross-sectional mailed survey.

PARTICIPANTS

189 randomly selected postmenopausal women from a general internal medicine practice in the Philadelphia area.

MAIN RESULTS

Of the 268 women (67%) who returned surveys, 189 were postmenopausal; 70 (37%) were currently using HRT and 21 (11 %) had previously used HRT. Respondents' mean age was 59.6 years; 64% were Caucasian, and 33% had completed college. Fifty-nine women (33%) thought HRT increased the risk of breast cancer, 22 (12%) thought it did not, and 100 (55%) were unsure. Mean perceived lifetime risk of breast cancer was 31% (range 0%-100%). After multivariate adjustment, current use of HRT was inversely associated with age (OR 0.96 for each one-year increase, 95% CI 0.940.98), and positively associated with Caucasian race (OR 2.73, 95% CI 1.40-5.32). Use of HRT was not associated with belief that HRT increases the risk of breast cancer, breast cancer risk perception, or perceived severity of breast cancer.

CONCLUSIONS

Belief that HRT increases the risk of breast cancer and high perceptions of breast cancer risk may not be important barriers to use of HRT. Efforts to improve decision making about HRT should focus on previously established barriers, such as perceptions of menopause and lack of physician discussion, rather than misconceptions about breast cancer risk.

[Comparative study between sodium stibogluconate BP 88 and meglumine antimoniate in cutaneous leishmaniasis treatment. II. Biochemical and cardiac toxicity]

Toxicity of two antimonial pentavalents were evaluated in 111 patients with cutaneous leishmaniasis. Forty-seven patients received meglumine antimoniate (Group I) and 64 patients, sodium stibogluconate BP 88 (Group II), 20 mg Sbv/kg/day for 20 days. Evaluation of aminotransferases, alkaline phosphatase, amilase, creatinine, urea, urine analysis and electrocardiogram were performed at baseline, on the tenth and twentieth day of treatment. Greater frequency of aminotransferase abnormal levels were observed on the tenth and twentieth days in group II (p < 0.001) and a greater proportion of amilase abnormal levels at the tenth day in the same group (p < 0.001). There was a greater variation of aminotransferases, alkaline phosphatase and amilase in the first ten days of treatment in group II (p < 0.01). On the twentieth day there was a greater variation of aminotransferase levels in group II (p = 0.02 and p = 0.03, respectively). Forty-three percent of group I and 54% of group II showed electrocardiographic abnormalities (p = 0.30).

The midvastus surgical approach in total knee arthroplasty

We report a study of 2 surgical approaches to the knee in 42 consecutive patients undergoing a total arthroplasty. They were divided into 2 groups. In Group 1 (n=17) the knee was exposed through classic medial parapatellar arthrotomy and in Group 2 (n=25) the knee was approached through the fibers of the medial vastus. Preoperative assessment did not reveal any statistical differences between the groups, and blood loss, operation time, biochemistry values and radiographic evaluation were also similar. However, a higher number of lateral releases, a loss of knee extension and a reduced range of motion were significantly associated with classical parapatellar arthrotomy. As the number of operative or postoperative complications was not increased, we recommend the mid-vastus approach for total knee arthroplasty.