Growth of CNTs on Fe-Si catalyst prepared on Si and Al coated Si substrates.

In this paper we report the effect of Al interlayers on the growth characteristics of carbon nanotubes (CNTs) using as-deposited and plasma etched Fe-Si catalyst films as the catalysts. Al interlayers having various thicknesses ranging from 2 to 42 nm were deposited on Si substrates prior to the deposition of Fe-Si catalysts. It was found that the Al interlayer diffuses into the Fe-Si catalyst during the plasma etching prior to the CNT growth, leading to the swelling and amorphization of the catalyst. This allows enhanced carbon diffusion in the catalyst and therefore a faster growth rate of the resulting CNTs. It was also found that use of an Al interlayer having a thickness of ∼3 ± 1 nm is most effective. Due to the effectiveness of this, the normally required catalyst etching is no longer needed for the growth of CNTs.

Coaxing bone marrow stromal mesenchymal stem cells towards neuronal differentiation: progress and uncertainties.

Multipotent adult stem cells capable of developing into particular neuronal cell types have great potential for autologous cell replacement therapy for central nervous system neurodegenerative disorders and traumatic injury. Bone marrow-derived stromal mesenchymal stem cells (BMSCs) appear to be attractive starting materials. One question is whether BMSCs could be coaxed to differentiate in vitro along neuronal or glial lineages that would aid their functional integration post-transplantation, while reducing the risk of malignant transformation. Recent works suggest that BMSCs could indeed be differentiated in vitro to exhibit some cellular and physiological characteristics of neural cell lineages, but it is not likely to be achievable with simple chemical treatments. We discussed recent findings pertaining to efforts in neuronal differentiation of BMSCs in vitro, and results obtained when these were transplanted in vivo.

APC/C regulation of axonal growth and synaptic functions in postmitotic neurons: the Liprin-alpha connection.

Protein ubiquitination has critical roles in neuronal physiology and defects in protein ubiquitination have been implicated in neurodegenerative pathology. The anaphase-promoting complex/cyclosome (APC/C) is one of two key E3 ubiquitin ligase complexes that functions in regulating cell cycle transitions in proliferating cells by acting on cyclins and components of the mitotic/meiotic apparatus. Documentation of APC/C's action beyond cell division is sparse. In the past year, however, novel and surprising roles for APC/C in postmitotic neurons, particularly in the modulation of axonal growth and synaptic functions, have been revealed. APC/C and its activator Cdh-1 are found in good abundance in neurons, and these seem to function at different cellular locations, modulating apparently diverse processes such as axonal growth and synaptic function. Interestingly, there also appears to be a single link to these apparently divergent actions of APC/C in neurons--the multi-domain, multi-functional scaffolding protein Liprin-alpha which is an APC/C substrate.

The syntaxins.

SUMMARY: The SNARE hypothesis predicts that a family of SNAP receptors are localized to and function in diverse intracellular membrane compartments where membrane fusion processes take place. Syntaxins, the prototype family of SNARE proteins, have a carboxy-terminal tail-anchor and multiple coiled-coil domains. There are 15 members of the syntaxin family in the human genome and 7 syntaxin-like genes in the yeast Saccharomyces cerevisiae. In conjunction with other SNAREs and with the cytoplasmic NSF and SNAP proteins, syntaxins mediate vesicle fusion in diverse vesicular transport processes along the exocytic and the endocytic pathway. They are crucial components that both drive and provide specificity to the myriad vesicular fusion processes that characterize the eukaryotic cell.

Vacuum extraction: does duration predict scalp injury?

OBJECTIVE: To identify variables that increase the chance of neonatal scalp injury during vacuum extraction. METHODS: We conducted a prospective observational study of 134 vacuum extraction-assisted deliveries at Olive View-UCLA Medical Center in 1995. Data collected included parity, gestational age, duration of first and second stages of labor, indication for operative delivery, station and position of fetal head, duration of vacuum application, number of "pop-offs," neonatal weight, and descriptions of scalp marks or injury. Cranial imaging studies were obtained if clinically indicated. RESULTS: There were 28 infants with scalp trauma, including 17 superficial lacerations, six large caputs, and 12 cephalohematomata; one infant had subgaleal, subdural, and subarachnoid hemorrhages. Logistic regression analysis showed duration of vacuum application to be the best predictor of scalp injury, followed by duration of second stage of labor and paramedian cup placement. Duration of vacuum application ranged from 0.5 to 26 minutes, with a median length of 3 minutes. The proportion of injuries was greater for applications exceeding 10 minutes (6 of 9) than for those 10 minutes or shorter (22 of 121, P < .01). We did not encounter any cases of clinically important scalp injury. CONCLUSIONS: Cosmetic scalp trauma occurred in 21% of our newborns delivered by vacuum extraction and was more common after longer vacuum applications, longer second stages, and paramedian cup placement.

A comparative study of laparoscopy and colpotomy for the removal of ovarian dermoid cysts.

OBJECTIVE: To compare laparoscope-assisted transvaginal removal of dermoid cysts to more standard laparoscopic cystectomy techniques. METHODS: We conducted a retrospective review of 44 laparoscopic dermoid removals performed at Olive View-UCLA Medical Center between 1992 and 1995. Cases were divided into three groups based on surgical approach: 1) conventional laparoscopic ovarian cystectomy, 2) laparoscopic ovarian cystectomy and removal of the freed mass via colpotomy, and 3) laparoscopic inspection, then transvaginal cystectomy via colpotomy. Surgical time, estimated blood loss, cyst spillage, and complications were compared. RESULTS: There were 11-19 patients in each group. The groups were similar in patient age, parity, and weight. Larger cysts tended to be removed by the laparoscopy-colpotomy techniques (mean diameter 10 cm) rather than by the purely laparoscopic approach (mean diameter 7 cm, P < .05). Cyst spillage occurred less often (43%, P < .05) and surgical time was shortest (mean 81 minutes, P < .05) with laparoscope-assisted transvaginal ovarian cystectomy compared with conventional laparoscopic techniques. Disposable laparoscopic instruments were used less often with transvaginal cystectomy (7%) than with conventional laparoscopic cystectomy (77%, P < .01). The difference in mean estimated blood loss in the cases using colpotomy (89 mL) compared with cases that did not (65 mL) was not statistically significant. Among the three groups, there were four major operative complications related to blood loss and infection. CONCLUSION: Laparoscope-assisted transvaginal ovarian cystectomy allows the removal of larger dermoid cysts, with less cyst spillage and savings in operative time and equipment compared with conventional laparoscopic cystectomy.

Predictive value of HemoCue capillary whole blood glucose measurements in pregnancy.

OBJECTIVE: We determined the ability of capillary whole blood glucose concentrations to predict venous plasma and whole blood glucose levels. METHODS: During a standard oral glucose tolerance test in 29 pregnant women, paired capillary and venous blood samples were collected for analysis of glucose concentrations by the HemoCue photometer and by central laboratory methods. RESULTS: Glucose concentrations determined serially in a single blood sample by the HemoCue method were highly reproducible, with a coefficient of variation of 2.3%. However, glucose levels in blood from two different fingersticks from the same patient varied on average by 3 mg/dL, with a maximum difference of 14 mg/dL. Although capillary whole blood glucose results obtained by the HemoCue method correlated well with venous plasma or whole blood glucose measurements (r = 0.98 and r = 0.97, respectively) over the range investigated (60-250 mg/dL), individual capillary whole blood glucose measurements were only a fair predictor of venous values, with 95% of measured venous levels within +/- 26 mg/dL and +/- 20 mg/dL for concentrations predicted for plasma and whole blood, respectively. CONCLUSION: Sampling factors rather than measurement accuracy limit the ability of capillary whole blood glucose measurements to predict venous concentrations.

Transvaginal probe ultrasonography. Diagnostic or outcome advantages in women with molar pregnancies.

This study attempted to determine whether patients with molar pregnancy initially evaluated by transvaginal ultrasound had earlier diagnoses and superior outcomes than did similar patients initially evaluated by only transabdominal scans. The medical records of 71 patients with molar pregnancy evacuated at the University of California at Los Angeles and affiliate hospital Olive View Medical Center between 1975 and 1988 were reviewed. Eight patients did not have ultrasound imaging prior to evacuation, and three had missing films. The remaining 60 patients were divided into two cohorts: 19 had transvaginal scans, while 41 had transabdominal scans only. The groups were compared retrospectively. Transvaginal pelvic ultrasound did not appear superior to the less expensive and less invasive transabdominal approach in identifying patients with molar pregnancy. These patients generally present with uteri over 10 weeks in size and often much larger; the gestation can be well visualized abdominally through the bladder window. Our study demonstrated no differences in outcome between patients from the two imaging groups.