Assessing the learning curve for the acquisition of laparoscopic skills on a virtual reality simulator.

BACKGROUND: The aim of this study was to develop summary metrics and assess the construct validity for a virtual reality laparoscopic simulator (LapSim) by comparing the learning curves of three groups with different levels of laparoscopic expertise. METHODS: Three groups of subjects ('expert', 'junior', and 'naïve') underwent repeated trials on three LapSim tasks. Formulas were developed to calculate scores for efficiency ('time-error') and economy of 'motion' ('motion') using metrics generated by the software after each drill. Data (mean +/- SD) were evaluated by analysis of variance (ANOVA). Significance was set at p < 0.05. RESULTS: All three groups improved significantly from baseline to final for both 'time-error' and 'motion' scores. There were significant differences between groups in time error performances at baseline and final, due to higher scores in the 'expert' group. A significant difference in 'motion' scores was seen only at baseline. CONCLUSION: We have developed summary metrics for the LapSim that differentiate among levels of laparoscopic experience. This study also provides evidence of construct validity for the LapSim.

Early identification and prognostic implications in disseminated intravascular coagulation through transmittance waveform analysis.

Efforts to improve the prognosis in disseminated intravascular coagulation (DIC) have been hampered by the lack of an early, useful and rapidly available diagnostic marker. More recently, a characteristic bi-phasic change in the light transmittance waveform profile of the APTT assay has been associated with DIC. In this prospective study, we have assessed the utility of this assay in the routine clinical setting. 1,470 samples were analysed from 747 patients and 41 patients had DIC. The sensitivity and specificity of the bi-phasic waveform pattern for DIC was 97.6% and 98% respectively. The appearance of a bi-phasic waveform preceded the development of abnormalities in the standard laboratory tests for DIC and waveform changes correlated closely with clinical events. In conclusion, transmittance waveform analysis is not only useful as an early diagnostic and single monitoring marker of DIC but the quantifiable and standardisable changes also allow for prognostic applicability in clinical management.

Potentiation of chlorambucil cytotoxicity in B-cell chronic lymphocytic leukemia by inhibition of DNA-dependent protein kinase activity using wortmannin.

In this study, we examined the ability of wortmannin to modulate chlorambucil (CLB) cytotoxicity in lymphocyte samples from patients with B-cell chronic lymphocytic leukemia (B-CLL). It has been suggested previously that enhanced cross-link repair is a primary mechanism of resistance to nitrogen mustards (NMs) in B-CLL. DNA-dependent protein kinase (DNA-PK) is involved in the repair of double-strand breaks and in rejoining steps in recombination mechanisms. Mutants defective in this process are hypersensitive to alkylating agents. We have recently demonstrated that the activity of DNA-PK is a determinant in the cellular response of B-CLL to CLB. The DNA-PK gene has homology to the P110 phosphatidylinositol 3-kinase (PI 3-K). Wortmannin, an inhibitor of P110 PI 3-K, also inhibits DNA-PK activity in vitro. We investigated the effect of wortmannin on DNA-PK activity and CLB toxicity in the lymphocytes from 11 patients with B-CLL. Our results demonstrate that DNA-PK activity is decreased after exposure to wortmannin in a dose-dependent manner. Wortmannin, at nontoxic concentrations, synergistically sensitized B-CLL lymphocytes to the effects of CLB. Moreover, we observed a significant correlation when we compared the fold decrease in DNA-PK activity and the synergistic value (I), obtained when wortmannin was used at 0.1 microM. In the resistant B-CLL lymphocyte samples, there was a highly significant correlation between the ability of wortmannin at 0.1 and 0.25 microM to decrease the level of DNA-PK activity and to increase CLB sensitivity. In a model of primary human tumor cells, our findings suggest that the inhibition of DNA-PK activity may be a powerful way to overcome resistance to NMs such as CLB and point to new possibilities to improve the effectiveness of NM therapy.

Novel and diagnostically applicable information from optical waveform analysis of blood coagulation in disseminated intravascular coagulation.

Transmittance waveform is the term applied to the optical profile generated from the process of clot formation on standard coagulation tests run on the MDA-180, a new-generation automated coagulation analyser. In patients with disseminated intravascular coagulation, a characteristically abnormal 'biphasic change' is seen on both the activated partial thromboplastin time and thrombin time waveforms. Increasing steepness of the initial slope on the waveform correlates with clinical deterioration and fulminant progression. Although the mechanism underlying the biphasic appearance remains to be elucidated, its identification provides the diagnostic laboratory with a simple, rapid and robust assay for disseminated intravascular coagulation that can help the clinician with urgent and appropriate therapeutic interventions.

Chronic duodenitis in Zaria, northern Nigeria.

Thirty-four consecutive patients presenting to the Endoscopy clinic of the Ahmadu Bello University Teaching Hospital, Zaria with symptoms of upper abdominal pain were investigated for chronic duodenitis by endoscopy and histology and for associated diseases. Twenty-two patients had histological evidence of chronic duodenitis. No clinical features separated these from those who had no duodenitis. Endoscopy was a good enough tool for diagnosis. Stool parasites were significantly commoner in those with histological duodenitis. Gastritis was also commoner in those with duodenitis. Ranitidine appeared superior to polycrol in relieving symptoms. Endoscopy is useful in the diagnosis of severe duodenitis. Specific ulcer healing drugs may be tried in treating symptoms associated with duodenitis, though their effectiveness is still open to further research.

Upper gastrointestinal endoscopy in Zaria, northern Nigeria.

The indications for and findings in 431 consecutive patients who had upper gastrointestinal endoscopy in Zaria from June 1978 to August 1982 are reviewed. The major indications were dyspepsia (78.1%), upper gastro-intestinal bleeding (12.1%) and portal hypertension (4.2%). Other indications were persistent vomiting, dysphagia and abdominal masses. The mean age of the patients was 32 years. The male: female ratio (3:1) was not different from that in the hospital population. There were no abnormal findings in 32.7%. 26.6% had duodenal ulcers. Duodenitis was noted in 24.8%, oesophageal varices in 6.3%, gastritis in 6.3% and hiatus hernia in 4.6%. In those who presented with upper-gastrointestinal haemorrhage, oesophageal varices (34.6%) and peptic ulcer (17.3%) were the commonest findings. Complication seen commonly were soreness in the throat and thrombophlebitis at the site of valium injection. One death was recorded from the procedure over the period.

A case of blastomycosis from Zaria, Nigeria.

A case of blastomycosis from Zaria, Nigeria is reported. The clinical features were indistinguishable from those of tuberculosis which is very common in this environment. Lack of response to anti-tuberculosis therapy within eight weeks prompted the search for other organisms which resulted in the isolation of Blastomyces dermatitidis. Compatible histological evidence was obtained. Subsequent favourable response to amphotericin B was evident. Infection with this organism should be included in the differential diagnosis of pulmonary and pleural lesions simulating tuberculosis in West Africa.