Carbon nanotubes randomly decorated with gold clusters: from nano2hybrid atomic structures to gas sensing prototypes

Carbon nanotube surfaces, activated and randomly decorated with metal nanoclusters, have been studied in uniquely combined theoretical and experimental approaches as prototypes for molecular recognition. The key concept is to shape metallic clusters that donate or accept a fractional charge upon adsorption of a target molecule, and modify the electron transport in the nanotube. The present work focuses on a simple system, carbon nanotubes with gold clusters. The nature of the gold-nanotube interaction is studied using first-principles techniques. The numerical simulations predict the binding and diffusion energies of gold atoms at the tube surface, including realistic atomic models for defects potentially present at the nanotube surface. The atomic structure of the gold nanoclusters and their effect on the intrinsic electronic quantum transport properties of the nanotube are also predicted. Experimentally, multi-wall CNTs are decorated with gold clusters using (1) vacuum evaporation, after activation with an RF oxygen plasma and (2) colloid solution injected into an RF atmospheric plasma; the hybrid systems are accurately characterized using XPS and TEM techniques. The response of gas sensors based on these nano(2)hybrids is quantified for the detection of toxic species like NO(2), CO, C(2)H(5)OH and C(2)H(4).

[Influence of fetal haemoglobin rate (FHb) on the oxidizing stress in homozygote sickle cell patient living in Abidjan, Côte-d'Ivoire]

Sickle cell anemia being involved in oxidizing stress, our objective was to study the influence of the fetal haemoglobin rate (FHb) on the lipoperoxidation markers in homozygote sickle cell patient in tropical African surroundings. The study population was composed of 73 subjects among whom 57 homozygote sickle cell subjects and 16 healthy control cases. These subjects were distributed in 4 groups according to FHb rate: group 1 (FHb rate under 10%), group 2 (FHb rate ranging from 10 and 20%), group 3 (FHb rate above 20%), group 4 (control cases with no sickle cell disease). On the biological level, the markers of plasma lipoperoxidation represented by substances reacting with thiobarbituric acid (TBARS) significantly increased in sickle cell patients comparatively to control cases (p = 10(-6)). A strong positive correlation (r = +0,70, p<0,01) was found between HbS and the TBARS rate. Comparison of biological parameters of homozygote sickle cell patients according to HbF rate shows that TBARS rate is all the more low as the HbF rate is high (p = 0,02). Moreover the number of irreversible and reversible sickle cells is higher in the group 1 which has the highest rate of TBARS. This observation is confirmed by a coefficient of positive correlation between TBARS and reversible sickle cells (r = +0,40, p < 0,01). This study strengthens the role played by HbF on the modulation of physiopathology of homozygote sickle cell anemia by the control, among others, of free radicals.

Early progressive encephalopathy in boys and MECP2 mutations

MECP2 mutations mainly occur in females with Rett syndrome. Mutations have been described in 11 boys with progressive encephalopathy: seven of nine with affected sisters and two de novo. The authors report four de novo occurrences: three pathogenic and one potentially pathogenic. Common features include failure to thrive, respiratory insufficiency, microcephaly, and abnormal motor control. MECP2 mutations should be assessed in boys with progressive encephalopathy and one or more of respiratory insufficiency, abnormal movements or tone, and intractable seizures.

Importance of Helicobacter pylori eradcation for maintenance of remission of drug associated peptic ulcer disease

BACKGROUND

The role of Helicobacter pylori (H. pylori) eradication in non-steroidal anti inflammatory drug (NSAID) users with peptic ulcer disease is controversial especially in countries with a high prevalence of the infection. Furthermore the value of low dose omeprazole for maintenance of remission is not yet known.

PATIENTS AND METHODS

138 symptomatic out-patients receiving continuous COX 1 NSAID therapy, were treated with omeprazole 40 mg/day upon endoscopic confirmation of gastro-duodenal ulceration or erosions while those infected with H. pylori received in addition clarithromycin 500 mg and amoxycillin 1000 mg twice daily during the first week of treatment. After endoscopic confirmation of healing at the end of week 5, the patients were randomized to receive omeprazole 10 mg (n=50) or 20 mg once daily (n=66) and endoscopy repeated after 20 weeks.

RESULTS

The overall healing rate (per protocol) at five weeks (116/128) was 90.6% while in 85.5% (65/76) eradication was successful. The healing rate for the H. pylori eradicated patients (58/65) was 89.2%. For those who failed eradication (8/11) it was 72.7% (NS), while for patients not infected with H. pylori at entry to the study (50/52) it was 96.2% (NS). An intention to treat analysis showed that after 20 weeks of omeprazole prophylaxis with the 10mg dose 86% (43/50) had maintained healing while for the 20mg dose a similar figure was observed (87.9; 58/66). Only three patients in the two groups (pp) had persistent H. pylori infection, all of whom relapsed. No patients discontinued treatment because of adverse effects of the drugs.

CONCLUSION

H. pylori eradication was not associated with impaired ulcer healing in a Middle Eastern population with symptomatic NSAID induced gastro/duodenal lesions, when a high healing dose of omeprazole (40 mg) was used. After eradication, omeprazole 10 or 20 mg per day were highly and equally effective for maintenance of gastroduodenal mucosal integrity during continued NSAID use. H. pylori should be eradicated from symptomatic Middle Eastern NSAID users with peptic ulcer disease.

Biliary obstruction secondary to combat-related foreign bodies: report of two cases

We present two cases with combat-related hepatic injury. These patients presented later with obstructive jaundice as seen on the percutaneous transhepatic cholangiography. Combat-related injuries are a rare cause of obstructive jaundice.

Assessment of bcl-2 expression as modulator of fas mediated apoptosis in acute leukemia

Apoptosis is the primary mechanism through which most chemotherapeutic agents induce tumor cell death. The balance in the expression of pro (Fas/CD95) and anti-apoptotic protein (Bcl-2) may control the response of leukemic cells to chemotherapy and subsequently affect the patient's prognosis. The aim of this study was to determine the levels of Bcl-2 and Fas expression on blast cells from patients with acute leukemia and to correlate the degree of expression to the clinical and laboratory prognostic factors and the patient's outcome. Forty newly diagnosed patients with acute leukemia (16 ALL, 24 AML) were included in the study. Ten normal subjects of matched age and sex were studied as a reference control group. The degree of Bcl-2 and Fas expression on acute leukemia blast cells were assessed before the start of therapy and on mononuclear cells after 1 year of follow up, using flow cytometry. The degree of Bcl-2 and Fas expression were significantly higher in AML (P<0.01,<0.05, respectively) and ALL (P<0.01, <0.05, respectively) as compared to controls. The expression of Fas and Bcl-2 was related to FAB type with the highest Bcl-2 and lowest Fas expression in M5 and T-ALL (P<0.01, for all). In ALL, patients responding to induction chemotherapy revealed lower Bcl-2 and higher Fas expression when compared to non-responders (P<0.05). In contrast, in AML the difference between responders and non-responders to induction chemotherapy regarding Bcl-2 and Fas expressions was not statistically significant (P>0.05). Bcl-2 and Fas expression were significantly elevated in the relapsed acute leukemia group (in both AML and ALL) when compared to those in remission (P<0.01, <0.05, respectively). Bcl-2 and Fas expression at diagnosis was not significantly different when those surviving were compared to the group who had died, either in the ALL or AML groups (P>0.05). Bcl-2 expression was significantly correlated to bone marrow blast cell counts (R=0.6, P<0.01), blast cell distribution ratio (R=0.4, P<0.05) and lymphadenopathy (R=0.33, P<0.05). Whereas Fas expression was significantly correlated to bone marrow blast cell counts (R=0.52, P<0.01). In conclusion, assessment of Bcl-2 and Fas expression at diagnosis in acute leukemia (1) could predict responsiveness to induction chemotherapy in ALL but not in AML group but (2) could not predict patients out come both in ALL and AML groups.

Placental site trophoblastic tumor in a patient with secondary infertility and radiological findings consistent with a leiomyoma: a case report

Placental site trophoblastic tumor (PSTT) is the rarest form of gestational trophoblastic diseases. We report a 40-year-old woman who presented initially after a year of secondary infertility with prolonged menstrual flow. Her last pregnancy ended in a suction dilation and curettage at 8 weeks' gestation for a missed abortion. A hysterosalpingogram revealed a solid 5 x 4.5 cm filling defect impinging on the endometrial cavity suggestive of a submucosal leiomyoma. A vaginal sonogram confirmed the findings. The patient underwent a laparotomy for excision of the 5-cm friable, necrotic mass that was performed by curetting. Pathologic examination of the specimen revealed sheets of intermediate trophoblastic cells characterized by large polyhedral cells and positive human placental lactogen staining consistent with PSTT. The patient eventually underwent total abdominal hysterectomy 4 weeks later with no evidence of residual tumor on histologic examination.

Placental site trophoblastic tumor in a patient with secondary infertility and radiological findings consistent with a leiomyoma: a case report

Placental site trophoblastic tumor (PSTT) is the rarest form of gestational trophoblastic diseases. We report a 40-year-old woman who presented initially after a year of secondary infertility with prolonged menstrual flow. Her last pregnancy ended in a suction dilation and curettage at 8 weeks' gestation for a missed abortion. A hysterosalpingogram revealed a solid 5 × 4.5 cm filling defect impinging on the endometrial cavity suggestive of a submucosal leiomyoma. A vaginal sonogram confirmed the findings. The patient underwent a laparotomy for excision of the 5-cm friable, necrotic mass that was performed by curetting. Pathologic examination of the specimen revealed sheets of intermediate trophoblastic cells characterized by large polyhedral cells and positive human placental lactogen staining consistent with PSTT. The patient eventually underwent total abdominal hysterectomy 4 weeks later with no evidence of residual tumor on histologic examination.

Studies in NZB IL-10 knockout mice of the requirement of IL-10 for progression of B-cell lymphoma

NZB mice develop an age-related malignant expansion of a subset of B cells, B-1 cells, with autocrine production of IL-10. IL-10, a pleiotropic cytokine with anti-inflammatory properties, is a potent growth and survival factor for malignant B cells. To further examine the in vivo requirement for IL-10 in the development and expansion of malignant B-1 clones in NZB mice, we developed a strain of homozygous IL-10 knockout (KO) mice on an NZB background. The NZB IL-10 KO mice develop peritoneal B-1 cells with approximately the same frequency as heterozygous and wild-type littermates. In contrast, the development of malignant B-1 cells in the peripheral blood and spleen, observed in wild-type NZB, rarely occurred in the NZB IL-10 KO. Phenotypic analysis of surface marker expression in splenic B cells indicated that, in contrast to the NZB with malignant B-1 splenic lymphoma, the surface marker expression of NZB IL-10 KO splenic B cells indicated that the majority of the B cells were typical B-2 cells. In the absence of IL-10, spontaneously activated B cells and antiapoptotic gene expression were reduced and lymphoma incidence was decreased. These results indicate that IL-10 is a critical factor for the progression of this B-cell malignant disease.

What are the primary concerns of recently graduated surgeons and how do they differ from those of the residency training years?

HYPOTHESIS

Graduated surgeons have differences in concerns when comparisons are made between fellows and practicing surgeons, practicing surgeons and residents, and male and female surgeons.

DESIGN AND SETTING

A survey was distributed to surgeons who graduated from 17 New England residency programs from 1993 to 1996, consisting of 9 demographic questions and 33 items coded on a Likert-type scale (with scores from 1 [least concerning] to 5 [most concerning]).

PARTICIPANTS

Surgical fellows and practicing surgeons recently graduated from general surgical residency programs in New England who had participated in a previous study as residents.

INTERVENTION

Distribution and completion of the survey.

MAIN OUTCOME MEASURE

Personal and career-oriented concerns of recently graduated surgical residents.

RESULTS

Personal issues continue to rank high for graduated residents, but the areas of greatest concern became more financially and career oriented. The top concerns of fellows were personal finances (mean score, 3.2), child rearing (mean score, 3.1), salary (mean score, 3.1), postponing family plans (mean score, 3.0), availability of role models (mean score, 2.9), and number of work hours (mean score, 2.8). The top concerns of practicing surgeons were salary (mean score, 3.2), personal finances (mean score, 3.1), number of referrals (mean score, 3.0), support for research (mean score, 2.7), child rearing (mean score, 2.7), and availability of role models (mean score, 2.7). Differences existed between men and women for child rearing, initiating personal relationships, maintaining personal relationships, maternity leave, and promotional advancement. Women were more concerned than men.

CONCLUSIONS

Assistance with career planning and job selection during the residency years should be enhanced to diminish the concerns about financial issues and the availability of role models after graduation. Many of the concerns among male and female graduates are still reflective of larger societal expectations, but some, such as promotional advancement, may be attenuated through guidance and mentoring of residents before job selection.

Effects of transforming growth factors-alpha and -beta on proliferation and apoptosis of rat theca-interstitial cells

Ovarian development, follicular growth and atresia require mechanisms regulating proliferation and death of ovarian cells including theca-interstitial (T-I) cells. Transforming growth factors-alpha and -beta (TGF-alpha and TGF-beta) are well recognized local modulators of T-I function. This study was performed to evaluate the effects of TGF-alpha and TGF-beta on ovarian T-I cell proliferation, differentiation and apoptosis. T-I cells from immature Sprague-Dawley rats were purified and incubated in chemically defined media. Proliferation was assessed by [3H]thymidine incorporation assay and by cell counting. Steroidogenically active cells were identified histochemically by detection of 3beta-hydroxysteroid dehydrogenase (3beta-HSD) activity. DNA was extracted and apoptosis was identified by detection of internucleosomal DNA cleavage producing the characteristic 'ladder pattern' of low-molecular weight (LMW) DNA following agarose gel electrophoresis. Quantification of apoptosis was carried out with the aid of 3'-end labeling of DNA fragments with [32P]-dideoxy-ATP. TGF-alpha and TGF-beta stimulated [3H]thymidine incorporation by 2.2- to 3.1-fold and 1.7- to 3.4-fold respectively (P<0.005). A combination of TGF-alpha and TGF-beta produced a synergistic increase in DNA synthesis by 6.7-fold (at 1 ng/ml of each TGF-alpha and TGF-beta; P<0.001) and tenfold (at 10 ng/ml of each TGF-alpha and TGF-beta; P<0.001). Cell counting revealed that TGF-alpha increased the total number of cells 2.8-fold and TGF-beta 2.8-fold. The combination of TGF-alpha and TGF-beta increased the total cell count 3.2-fold, compared with control (P<0.05). The percentage of the steroidogenically active cells was 37+/-9% (mean+/-s.e.m. ) in the control cultures, 50+/-5% in the presence of TGF-alpha, 42+/-8% in the presence of TGF-beta, and 47+/-13% in the presence of both TGF-alpha and TGF-beta. TGF-alpha decreased apoptosis by 63+/-14% (P=0.02) while TGF-beta had no statistically significant effect. TGF-alpha in combination with TGF-beta produced the greatest inhibition of apoptosis by 73+/-8% (P=0.01). These findings demonstrate that TGF-alpha and -beta stimulate proliferation of both steroidogenically active and inactive T-I cells. Furthermore, TGF-alpha alone and in combination with TGF-beta protects T-I cells from apoptotic death. These effects of TGFs may be important in physiologic maintenance of ovarian mesenchymal growth and homeostasis as well as in pathophysiologic conditions associated with excessive growth of the T-I compartment, such as polycystic ovary syndrome.

Acute granulomatous schistosomal cholecystitis

Schistosomal cholecystitis is a rare entity with less than 10 cases described in the medical literature [1-3]. It is unclear whether schistosomal eggs deposited in the wall of the gallbladder trigger a clinically manifest acute cholecystitis, since most of the cases described were also found to have concomitant gallstones. Herein, we report a patient who developed acute schistosomal granulomatous acalculous cholecystitis. The clinical presentation, chronology of events and pathological findings strongly support the association between cholecystitis and schistosomal infection.