Fate and role of peroxisomes during the life cycle of the yeast Saccharomyces cerevisiae: inheritance of peroxisomes during meiosis

Sporulation in the yeast Saccharormyces cerevisiae is a meiotic developmental process that occurs in MATa/MATalpha heterozygotes in response to nutrient deprivation. Here, the fate and role of peroxisomes during sporulation and germination has been examined by a combination of immunoelectron microscopy and the use of pex mutants defective in peroxisomal functions. Using a green fluorescent protein probe targeted to peroxisomes we show that peroxisomes are inherited through meiosis and that they do not increase in number either during sporulation or spore germination. In addition, there is no requirement for peroxisome degradation prior to spore packaging. Unlike the situation in filamentous fungi, peroxisomes do not proliferate during the yeast life cycle. Functional peroxisomes are dispensable for efficient meiotic development on acetate medium since homozygous delta pex6 diploids sporulated well and produced mature spores that were resistant to diethyl ether. Like haploids, diploid cells can proliferate their peroxisomes in response to oleate as sole carbon source in liquid medium, but under these conditions they do not sporulate. On solid oleate medium, homozygous pex5, delta pex6, and pex7 cells were unable to sporulate efficiently, whereas the wild type was. The results presented here are discussed in terms of the transmission of organelles to progeny cells.

The nitura study--effect of nitroglycerin or urapidil on hemodynamic, metabolic and respiratory parameters in hypertensive patients with pulmonary edema

OBJECTIVE

To assess the effects of nitroglycerin or urapidil on hemodynamic, respiratory and metabolic parameters in hypertensive patients with pulmonary edema.

DESIGN

Open, randomized and prospective clinical study.

SETTING

Out-of-hospital setting and Emergency Department in a 2000-bed hospital.

PATIENTS

Hundred twelve patients with evidence of hypertensive crises with pulmonary edema (systolic blood pressure (SBP) > 200 mmHg and/or diastolic blood pressure (DBP) > 100 mm Hg and rales over both lungs) at the time when the emergency physician arrived.

INTERVENTIONS

The out-of-hospital treatment consisted of oxygen via face mask, 80 mg furosemide i.v., 10 mg morphium s.c., and either nitroglycerin sublingually (initial dose: 0.8 mg; repetitive administration of 0.8 mg every 10 min to a cumulative dose of 3.2 mg) or urapidil (initial dose: 12.5 mg i.v.; repetitive administration every 15 min to a cumulative dose of 50 mg). If SBP was more than 180 mm Hg and/or DBP more than 90 mm Hg on admission, antihypertensive treatment was continued with nitroglycerin (0.3-3 mg/h) or urapidil (5-50 mg/h).

MEASUREMENTS AND RESULTS

Blood pressure (BP) was measured every 5 min with the use of an automatic oscillometric device. Serum lactate, PO2, pH value, and base excess (BE) were evaluated on admission and 6 h later. Blood pressure, serum lactate and BE on admission were significantly lower (SBP: 155 +/- 30 vs 179 +/- 33 mm Hg; p = 0.0002; DBP: 82 +/- 17 vs 93 +/- 19 mmHg; p = 0.001; lactate: 2.2 +/- 1.6 vs 3.9 +/- 2.7; p = 0.0001; BE: -1.9 +/- 3.9 vs -4.4 +/- 1.7; p = 0.0005) and PO2 and pH values were significantly higher in the urapidil group compared to the nitroglycerin group (PO2: 75 +/- 25 vs 66 +/- 17; p = 0.036; pH: 7.33 +/- 0.08 vs 7.29 +/- 0.09; p = 0.042). After 6 h no differences between the two groups were observed.

CONCLUSION

The more pronounced BP reduction in the urapidil group was associated with an improved respiratory and metabolic situation in hypertensive patients with pulmonary edema. Therefore, urapidil is a valuable alternative to nitroglycerin in patients with pulmonary edema and systemic hypertension.

Epiluminescence microscopy-based classification of pigmented skin lesions using computerized image analysis and an artificial neural network

Epiluminescence microscopy (ELM) is a non-invasive technique for in vivo examination which can provide additional criteria for the clinical diagnosis of pigmented skin lesions (PSLs). In the present study we attempt to determine whether PSLs can be automatically diagnosed by an integrated computerized system. This system should recognize the PSL, automatically extract features and use these features in training an artificial neural network, which should--if sufficiently trained--be capable of recognizing and classifying a new PSL without human aid. One hundred and twenty images of randomly selected histologically proven PSLs (33 common naevi, 48 dysplastic naevi and 39 malignant melanomas) were used in this study. The images were digitally obtained and the morphological features of the PSLs were extracted electronically without human assistance. The numerical data were then divided into learning and testing cases and linked to an artificial neural network for training and for further classification of lesions that the system had not been trained on. Our results show that the computerized system was able to automatically identify 95% of the PSLs presented. The sensitivity and specificity of the computerized system were 90% and 74% respectively. In contrast, when differentiating between individual types of lesions, the system performed at true positive rates of only 38% for malignant melanoma, 62% for dysplastic naevi and 33% for common naevi. Our data indicate that (1) ELM images of PSLs provide an excellent source for digital image analysis; (2) the vast majority of PSLs can be correctly identified by a relatively simple (and thus not "intelligent") application of digital image analysis; (3) automatic feature extraction based mainly on ABCD rules provides reliable data on the distinction between benign and malignant PSLs; and (4) there is evidence that artificial neural networks can be trained to adequately discriminate between benign and malignant PSLs.

Diagnostic informativeness of compressed digital epiluminescence microscopy images of pigmented skin lesions compared with photographs

Epiluminescence microscopy (ELM) is a useful method for improved diagnostic accuracy in early cutaneous melanoma. Conventional photographs of ELM images are commonly used for clinical research and documentation. Electronic images have advantages compared with photographs and are essential for medical informatics, computerized learning and telemedicine. Compression of electronic images allows a reduction in volume of data, but significant image deterioration may occur at high compression rates. We sought to study the diagnostic informativeness of compressed digital ELM images compared with conventional photographs. Fifty photographs of pigmented skin lesions, including 23 melanomas, were presented to eight dermatologists as photographic slides and as digital images with 30:1 Joint Photographic Experts Group (JPEG) compression. The diagnostic performance of the media and the readers was described in terms of sensitivity, specificity and areas under receiver operating characteristic curves (AUC). Agreement between the readings of the two types of media regarding the presence or absence of ELM criteria was assessed using kappa (kappa) statistics. The mean AUC was 0.81 (95% confidence interval [CI] = 0.73-0.90) for slides and 0.81 (95% CI = 0.72-0.90; P = 0.89) for digital images. Agreement between the readings of the two types of media regarding the presence or absence of ELM criteria ranged from kappa = 0.55 (95% CI = 0.22-0.88) for grey-blue area to kappa = 0.89 (95% CI = 0.74-1.00) for radial streaming. In conclusion, digital ELM images with 30:1 JPEG compression appear to be as informative as photographic slides when used to differentiate between melanoma and non-melanoma.

Adjuvant interferon alfa-2a treatment in resected primary stage II cutaneous melanoma. Austrian Malignant Melanoma Cooperative Group

PURPOSE

Patients with primary cutaneous melanoma with a Breslow thickness > or = 1.5 mm have only a 30% to 70% probability of survival after surgery, and no adjuvant therapy has so far improved this outcome. Since interferon alfa-2a (IFNalpha2a) exhibits antitumor activity in metastatic melanoma, we investigated whether adjuvant IFNalpha2a diminishes the occurrence of metastases and thus prolongs disease-free survival in melanoma patients after excision of the primary tumor.

PATIENTS AND METHODS

In a prospective randomized study, 311 melanoma patients with a Breslow thickness > or = 1.5 mm were assigned to either adjuvant IFNalpha2a treatment (n = 154) or observation (n = 157) after excision of the primary tumor. IFNalpha2a was given daily at a dose of 3 mIU subcutaneously (s.c.) for 3 weeks (induction phase), after which a dose of 3 mIU s.c. three times per week was given over 1 year (maintenance phase).

RESULTS

Prolonged disease-free survival was observed in patients treated with IFNalpha2a versus those who underwent surgery alone. This difference was significant (P = .02) for all patients enrolled onto the study (intention-to-treat analysis) at a mean observation time of 41 months. Subgroup analysis showed that Breslow tumor thickness had no influence on treatment results in the groups of patients investigated.

CONCLUSION

Adjuvant IFNalpha2a treatment diminishes the occurrence of metastases and thus prolongs disease-free survival in resected primary stage II cutaneous melanoma patients.

Molecular and biochemical characterization of phosphoglucomutases from Entamoeba histolytica and Entamoeba dispar

Entamoeba histolytica and Entamoeba dispar have only recently been defined as two separate species. E. histolytica, the pathogenic species, is the microorganism causing invasive intestinal amoebiasis and/or liver abscess, while the morphologically similar E. dispar is nonpathogenic and noninvasive. The gold standard for the distinction of the two species has been the isoenzyme electrophoresis of phosphoglucomutases (EC 5.4.2.2) and hexokinases (EC 2.7.1.1), but there had also been a controversy about the possibility of a conversion of isoenzyme patterns. In this study, we cloned the phosphoglucomutase (PGM) cDNAs from the pathogenic and the nonpathogenic species. The deduced amino acid sequences were only 2.4% different. The cDNAs were expressed in Escherichia coli under the control of a T7 RNA polymerase promoter. The recombinant polypeptides displayed strong phosphoglucomutase activity, each of the recombinant enzymes comigrated with its natural counterpart from E. histolytica and E. dispar in the starch gel electrophoresis. Our results give a biochemical interpretation of the PGM isoenzyme pattern and support the clear distinction between the two species.

Regulation of the yeast SPS19 gene encoding peroxisomal 2,4-dienoyl-CoA reductase by the transcription factors Pip2p and Oaf1p: beta-oxidation is dispensable for Saccharomyces cerevisiae sporulation in acetate medium

The yeast SPS19 gene encoding the peroxisomally targeted 2,4-dienoyl-CoA reductase shares its promoter region (291 bp) with the sporulation-specific gene SPS18. SPS19 is induced during sporulation in diploids but to a lesser extent than SPS18; under oleate induction conditions, SPS19, but not SPS18, is transcribed via an oleate response element (ORE) independently of ploidy or sporulation. The SPS19 ORE is the binding target of the Pip2p and Oaf1p transcription factors, and an SPS19-lacZ reporter gene, which is highly expressed in oleate-induced cells, is not activated in haploids devoid of either protein. We examined the expression of CYC1-lacZ reporter constructs carrying the SPS19 and CTA1 OREs in diploids propagated under sporulation conditions and have shown that OREs are not sufficient for heterologous expression during yeast development. In addition, diploids deleted at either PIP2 or OAF1 demonstrated abundant ascosporogenesis, indicating that these genes are not essential for sporulation. A deltapex6 strain lacking peroxisomal structures and one devoid of fatty acyl-CoA oxidase (deltapox1), the first step in fungal beta-oxidation, were both proficient for sporulation and, hence, beta-oxidation and the peroxisomal compartment containing it are dispensable for meiotic development.

Noninvasive assessment of cardiac output in critically ill patients by analysis of the finger blood pressure waveform

OBJECTIVE

To assess whether the measurement of cardiac output by computer-assisted analysis of the finger blood pressure waveform can substitute for the thermodilution method in critically ill patients.

DESIGN

Prospective data collection.

SETTING

Emergency department in a 2000-bed inner city hospital

PATIENTS

Forty-six critically ill patients requiring invasive monitoring for clinical management were prospectively studied.

INTERVENTIONS

Under local anesthesia a 7-Fr pulmonary artery catheter was inserted via the central subclavian or jugular vein. Cardiac output was determined by the use of a cardiac output computer and injections of 10 mL ice-cold glucose 5%. Noninvasive cardiac output was calculated from the finger blood pressure waveform by the use of the test software program.

MEASUREMENTS AND MAIN RESULTS

Three hundred twenty-three pairs of invasive and noninvasive hemodynamic measurements were collected in intervals of 30 mins from 46 patients (mean age 61.9 +/- 12.4 yrs; 35 male, 11 female). The average cardiac index during the study period was 2.83 L/min/m2 (range 0.97 to 5.56). The overall discrepancy between both measurements was 0.14 L/min/m2 (95% confidence interval: 0.10-.018, p < .001). Seventy-five (23.2%) measurements had an absolute discrepancy > +/- 0.50 L/min/m2. Noninvasive and invasive comparisons of mean differential cardiac output were out of phase for 9.7% of all readings.

CONCLUSION

Computer-assisted analysis of finger blood pressure waveform to assess cardiac output is not a substitute for the thermodilution method due to a high percentage (23.2%) of inaccurate readings; however, it may be a useful tool for the detection of relative hemodynamic trends in critically ill patients.

Prediction of early complications in patients with acute myocardial infarction by calculation of the ST score

STUDY OBJECTIVE

To assess the relationship between the sum of ST-segment elevations (ST score) in the admission ECG and the occurrence of early complications in patients with acute myocardial infarction (MI).

METHODS

We conducted an observational study of patients who presented with acute anterior or inferior MI to the ED of a 2,000-bed inner-city hospital. Age, sex, time from onset of pain and the start of thrombolysis, and ST score were evaluated by the emergency physician. "Early complications" were defined as acute congestive heart failure or severe rhythm disturbances in the 24 hours after the start of thrombolysis. The outcome measures were the relationship between ST score and the occurrence of early complications; the influence of age, sex, or time between onset of pain and thrombolysis; and identification of a cutoff value with the highest sensitivity and specificity for prediction of complications.

RESULTS

We included 243 patients (194 men, 49 women; mean age, 56.6 years) with acute MI (anterior, 119; inferior, 124) who underwent thrombolysis in our analysis. ST score was significantly greater in patients with early complications, compared with patients without complications (anterior, 10.3 versus 19.4 mm [P < .001]; inferior, 6.9 versus 10.4 mm [P < .001]). Receiver-operator curve analysis revealed an ST score of 13 mm in patients with anterior MI and 9 mm in patients with inferior MI as the cutoff value with the greatest sensitivity and specificity for predicting early complications of MI. (For anterior MI, sensitivity was .79, specificity .73; for inferior MI, sensitivity was .64 and specificity .68.). On multivariate regression analysis, ST score was an independent predictor of the occurrence of at least one complication. (For anterior MI, the odds ratio [OR] was 9.7 and the 95% confidence interval [CI] 3.9 to 25.1; for inferior MI the OR was 5.0 and the 95% CI 2.0 to 12.8). Age, sex, and interval from onset of pain to treatment had no significant effect on the occurrence of early complications.

CONCLUSION

The absolute ST score is useful in estimating the probability of early complications in patients with acute MI receiving thrombolytic therapy. A cutoff value of 13 mm for anterior MI and 9 mm for inferior MI stratifies patients into high- and low-risk subgroups for the development of acute congestive heart failure and severe rhythm disturbances during the first 24 hours of hospitalization.

The association between blood lactate concentration on admission, duration of cardiac arrest, and functional neurological recovery in patients resuscitated from ventricular fibrillation

OBJECTIVE

To assess the association between arterial lactate concentration on admission and the duration of human ventricular fibrillation cardiac arrest, and to what degree the arterial lactate concentration on admission is an early predictor of functional neurological recovery in human cardiac arrest survivors.

DESIGN

Cohort study. Arterial lactate concentrations and out-of-hospital data concerning cardiac arrest and cardiopulmonary resuscitation were collected retrospectively according to a standardized protocol. Functional neurological recovery was assessed prospectively at regular intervals for 6 months.

SETTING

Emergency department of an urban tertiary care hospital.

PATIENTS

A total of 167 primary survivors of witnessed out-of-hospital ventricular fibrillation cardiac arrest.

MEASUREMENTS

The association between arterial lactate concentration on admission, the duration of cardiac arrest, and functional neurological recovery was assessed. Further, we assessed whether admission concentrations of arterial lactate and duration of cardiac arrest can predict unfavorable functional neurological recovery. Functional neurological recovery was measured in cerebral performance categories (CPC). No or minimal functional impairment (CPC 1 and 2) was defined as favorable outcome; the remaining categories (CPC 3, 4 and 5) were defined as unfavorable functional neurological recovery.

RESULTS

In 167 patients, a weak association between total duration of cardiac arrest and admission levels of lactate (r = 0.49, P < 0.001) could be shown. With increasing admission concentrations of arterial lactate functional neurological recovery was more likely to be unfavorable (OR 1.15 per mmol/l increase, 95% CI 1.04-1.27). Nevertheless, only at very high levels of lactate (16.3 mmol/l) could unfavorable neurological recovery be detected with 100% specificity, yielding a very low sensitivity of 16%.

CONCLUSIONS

The arterial admission lactate concentration after out-of-hospital ventricular fibrillation cardiac arrest is a weak measure of the duration of ischemia. High admission lactate levels are associated with severe neurological impairment. However, this parameter has poor prognostic value for individual estimation of the severity of subsequent functional neurological impairment.

Lymph node sonography versus palpation for detecting recurrent disease in patients with malignant melanoma

The aim of this study was to examine the efficacy of lymph node palpation versus high resolution lymph node sonography for the detection of lymph node metastases in patients with malignant melanoma. We retrospectively evaluated 2256 pairwise lymph node examinations of the cervical, axillary and inguinal region by palpation and sonography in 264 patients with resected melanomas greater than 0.75 mm of invasion thickness. Lymph node metastases occurred in 50 patients (19%) which were detected in 38 (76%) by both methods in agreement. In 7 cases (14%) palpation failed, in 3 cases (6%) sonography failed and in 2 cases both methods failed to identify metastases. The overall sensitivity of detecting metastatic disease was 82% for palpation and 90% for sonography which was statistically not different. The overall specificity by sonography (99%) was significantly better than for lymph node palpation (88%). Taking into account the results of this analysis, we conclude that patients with a negative result by lymph node palpation do not need further sonography for verification. However, any suspect result by palpation should be additionally evaluated by lymph node sonography in order to rule in or out metastatic disease.

Arg506 to Gln mutation in the factor V gene causes poor fibrinolytic response in children after venous occlusion

To determine to what extent the Arg506 to Gln mutation in the factor V gene influences the fibrinolytic response after 20 min venous occlusion (VO) we investigated a population of APC resistant children (n = 60) and a group of age-matched healthy controls (n = 25). After 20 min VO, symptomatic (n = 30) carriers of the common factor V mutation showed significantly reduced t-PA activities compared with asymptomatic (n = 30) carriers (p <0.0001) and healthy controls (p <0.0001). In contrast, PAI 1 activity was significantly (p <0.0001) higher before and after VO in children with the factor V mutation compared with healthy children. No difference was found between symptomatic and asymptomatic probands. A significantly lower PAI 1 antigen decrease along with a lower t-PA antigen release was found in the APC resistant children compared with the controls. No significant difference was seen between individuals with and without previous vascular insults. As the lack of t-PA activity after VO in symptomatic carriers is the most conspicuous result, we suggest that the factor V gene mutation itself might induce the fibrinolytic impairment by increasing the thrombin levels and thus increasing the recently described thrombin-activable fibrinolysis inhibitor (TAFI).

The Saccharomyces cerevisiae peroxisomal 2,4-dienoyl-CoA reductase is encoded by the oleate-inducible gene SPS19

beta-Oxidation is compartmentalized in mammals into both mitochondria and peroxisomes. Fatty acids with double bonds at even-numbered positions require for their degradation the auxiliary enzyme 2,4-dienoyl-CoA reductase, and at least three isoforms, two mitochondrial and one peroxisomal, exist in the rat. The Saccharomyces cerevisiae Sps19p is 34% similar to the human and rat mitochondrial reductases, and an SPS19 deleted strain was unable to utilize petroselineate (cis-C18:1(6)) as the sole carbon source, but remained viable on oleate (cis-C18:1(9)). Sps19p was purified to homogeneity from oleate-induced cells and the homodimeric enzyme (native molecular weight 69,000) converted 2,4-hexadienoyl-CoA into 3-hexenoyl-CoA in an NADPH-dependent manner and therefore contained 2,4-dienoyl-CoA reductase activity. Antibodies raised against Sps19p decorated the peroxisomal matrix of oleate-induced cells. SPS19 shares with the sporulation-specific SPS18 a common promoter region that contains an oleate response element. This element unidirectionally regulates transcription of the reductase and is sufficient for oleate induction of a promoterless CYC1-lacZ reporter gene. SPS19 is dispensable for growth and sporulation on solid acetate and oleate media, but is essential for these processes to occur on petroselineate.

Safety and efficacy of urapidil and sodium nitroprusside in the treatment of hypertensive emergencies

OBJECTIVE

To assess the safety and efficacy of urapidil compared to sodium nitroprusside in the treatment of hypertensive emergencies.

DESIGN

Randomized, prospective clinical study.

SETTING

Emergency department in a 2000-bed inner city hospital.

PATIENTS

Eighty-one patients with hypertensive emergencies defined as elevation of systolic blood pressure above 200 mmHg and/or diastolic blood pressure above 110 mmHg plus evidence of end-organ damage were included in the study protocol. The efficacy of therapy was defined as 1) blood pressure reduction below 180/95 mmHg within 90 min and 2) no re-elevation of blood pressure during a 4-h follow-up period in primary responders. The safety of both drugs was defined as the number of minor and major side effects during treatment.

INTERVENTIONS

Patients received either sodium nitroprusside (n = 35; continuous intravenous administration with a starting dose of 0.5 microgram/kg per min; increase in increments of 0.5 microgram/kg per min every 15 min until response to treatment or a maximum of 3 micrograms/kg per min) or urapidil (n = 46; intravenous bolus; starting dose: 12.5 mg; repetitive administration of 12.5 mg every 15 min until response or a maximum dose of 75 mg).

MEASUREMENTS AND RESULTS

Blood pressure was measured every 2.5 min by using a non-invasive oscillometric blood pressure measurement unit. Response to treatment within 90 min was observed in 75 (93%) patients (urapidil: n = 41 [89%]; nitroprusside: n = 34 [97%]; p = 0.18). During the follow-up period 8/34 (24%) patients in the nitroprusside group and 1/41 (2%) patients in the urapidil group exhibited blood pressure re-elevation. Major side effects were observed in seven patients receiving nitroprusside and two patients in the urapidil group (p = 0.04).

CONCLUSION

Urapidil is equally effective, compared to sodium nitroprusside, in the treatment of hypertensive emergencies. Due to a smaller number of adverse events, urapidil is a reasonable alternative to nitroprusside in the treatment of hypertensive emergencies.

Statistical evaluation of epiluminescence microscopy criteria in the differential diagnosis of malignant melanoma and pigmented basal cell carcinoma

Pigmented basal cell carcinoma (PBCC) is a tumour with distinct clinical features which occasionally may be difficult to differentiate from malignant melanoma (MM). The purpose of this study was to re-examine the epiluminescence microscopy (ELM) criteria for PBCC and to determine their statistical significance in the differential diagnosis of MM. Fifty histologically verified pigmented skin lesions (25 PBCCs and 25 MMs) were investigated using ELM for the presence of ELM criteria; their significance was determined by calculating the odds ratios. We found that individual ELM criteria have different weights of significance in the differential diagnosis of PBCC (leaf-like distribution of diffuse pigmentation, gradual thinning at the periphery and telangiectasia) and MM (pigment network, black and grey pigmentation, radial streaming, pseudopods, brown globules and black dots). Selected patterns of ELM criteria adjusted to the distinct types of pigmented skin lesions are characteristic features for preoperative diagnosis. The prevalence of distinct ELM criteria in PBCC and MM is of critical value in differentiating between the two types of lesions.

A simple and reliable reverse-phase high-performance liquid chromatographic procedure for determination of paclitaxel (taxol) in human serum

A simple, fast, and reliable isocratic (mobile phase: acetonitrile/methanol/water [48/11/41], reverse-phase (C18 column) high-performance liquid chromatography method for the determination of paclitaxel concentration in human serum is presented. The procedure uses a new and convenient one-step sample-purification procedure that requires only 400 microliters of sample and uses N-heptylbenzamide as an internal standard. Paclitaxel is detected by UV absorbance measurement at 227 nm. The method has a broad linear range (0.01 to 10 mg/l, or 0.012 to 11.7 mumol/l; r > 0.999), and the detection limit is 0.01 mg/l (0.012 mumol/l). The deviation from target value is < or = 1.5%, and coefficients of variation are < or = 13.8% within runs and < or = 15.3% between runs. Recovery paclitaxel is > or = 92.6%. No interferences were observed from endogenous compounds or from more than 30 drugs that may be administered with paclitaxel. Docetaxel, which is not concurrently administered, coeluted with paclitaxel. Compared with previously published high-performance liquid chromatography procedures for the determination of paclitaxel, the particular advantage of the method presented here is its simple and rapid single-step sample-purification procedure, which makes a high recovery of paclitaxel from serum samples possible and results in a pure extract, avoiding interferences from endogenous compounds. The method is suitable for pharmacological studies and routine analysis.

Quantification of vascularity in nodular melanoma and Spitz's nevus

Spitz's nevi are acquired benign melanocytic skin tumors. Usually they are differentiated from nodular melanoma by clinical and histopathological criteria. Since Spitz's nevi are one of the most common simulators of nodular melanomas their bizarre histopathology may cause diagnostic confusion and make it difficult to differentiate these two melanocytic tumors. One of the histologic features shared by Spitz's nevus and nodular melanoma is prominent vascularity. The ability of malignant melanoma to induce angiogenesis is well established whereas benign melanocytic tumors do not have a prominent overall vascularity. The purpose of this study was to find out whether the degree of vascularity of nodular melanomas differs significantly from that of benign Spitz's nevi. In this study the number of microvessels and the vessel area were determined in 23 Spitz's nevi and 16 nodular melanomas. The number of microvessels and the vessel area were determined on Ulex Europaeus agglutinin I-stained sections by computer-assisted image analysis. Two methods of measurement were used, namely systematic and selective sampling. Measurement of the whole tumor specimen (systematic sampling) revealed a vessel count of 10.83/field (SD +/-5.97) for Spitz's nevi whereas nodular melanomas exhibited a significantly lower (p=0.04) vessel count of 6.44/field (SD +/-3.85). This difference was even more pronounced when the vessel area (Spitz's nevi: 17.85x10-4mm2, SD +/-10.32; nodular melanomas: 7.88x10-4mm2, SD +/-5.23) was investigated (p < 0.001). The difference in vessel area and vessel count was insignificant for areas exhibiting the greatest vascularity (selective sampling). Measurement of vessel count and vessel area lead us to conclude that Spitz's nevi have a significantly higher vascularity than do nodular melanomas. Our results thus indicate that angiogenesis in these pigmented lesions is not correlated with malignancy.

Molecular biology of the hexokinase isoenzyme pattern that distinguishes pathogenic Entamoeba histolytica from nonpathogenic Entamoeba dispar

The electrophoretic patterns of hexokinase and phosphoglucomutase have been widely used to distinguish Entamoeba histolytica from Entamoeba dispar isolates. Although E. histolytica and E. dispar, previously called pathogenic and nonpathogenic Entamoeba histolytica, differ clearly in sequences of many homologous genes, a conversion between the two has been reported by several laboratories, in each case showing the conversion of hexokinase (ATP, D-hexose 6-phosphotransferase, EC 2.7.1.1) isoenzyme patterns. An apparent mobility shift of this enzyme may either be due to posttranslational modification or processing, or to the appearance of a new isoform encoded by a second gene. In this study we observed that the four observed bands in the isoenzyme patterns of pathogenic and nonpathogenic forms of Entamoeba were correlated with four different cDNAs, and that the four recombinant hexokinases produced in Escherichia coli comigrated with their natural counterparts. Polymerase chain reaction (PCR) experiments did not reveal hidden genes which might be responsible for conversion phenomena. These results strongly support the redefinition of pathogenic and nonpathogenic Entamoeba histolytica as two closely related species Entamoeba histolytica and Entamoeba dispar.

Double-blind trial of botulinum A toxin for the treatment of focal hyperhidrosis of the palms

We performed a randomized double-blind study within-group comparison in 11 patients to study the effect of subcutaneous injections of botulinum A toxin in focal hyperhidrosis of the palms. A total dose of 120 mU (mouse units) of botulinum A toxin (Dysport) was injected into six different sites on one palm, whereas the other was injected with sterile saline. Objective quantification of sweat production was performed using digitized ninhydrin-stained sheets. Three weeks after treatment, the mean reduction of sweat production in the botulinum A toxin-treated palms was 26% (P < 0.001), after 8 weeks 26% (P = 0.002) and after 13 weeks 31% (P < 0.001). Subjective assessment of sweat production by the patients using a visual analogue scale showed a 38% improvement in the botulinum A toxin-treated palms at 3 weeks (P = 0.002), 40% at 8 weeks (P = 0.002) and 38% at 13 weeks (P = 0.002). Neither the objective measurement nor the subjective rating showed a statistically significant reduction of sweating in the placebo-treated palms. Three patients reported reversible minor weakness of powerful handgrip after injection at the toxin-treated site, lasting between 2 and 5 weeks.

Blood glucose concentration after cardiopulmonary resuscitation influences functional neurological recovery in human cardiac arrest survivors

Experimental data suggest that postischemic blood glucose concentration plays an important role in modulating both ischemic cerebral infarction and selective neuronal necrosis. This study investigated the association between functional neurological recovery and blood glucose concentrations in human cardiac arrest survivors. A group of 145 nondiabetic patients were evaluated after witnessed ventricular fibrillation cardiac arrest. Data regarding cardiac arrest were collected according to an internationally accepted protocol immediately after arrival. Blood glucose was measured on admission and 6, 12, and 24 h thereafter. To control for duration of cardiac arrest and cardiogenic shock, both known to influence outcome as well as blood glucose, levels, Spearman rank partial correlation was used. In this multivariate analysis, a high admission blood glucose level tended to be associated with poor neurological outcome (rs = -0.16, n = 142, p = 0.06). The association between high median blood glucose levels over 24 h and poor neurological outcome was strong and statistically significant (rs = -0.2, n = 145, p = 0.015). High blood glucose concentrations occurring over the first 24 h after cardiac arrest have deleterious effects on functional neurological recovery. Whether cardiac arrest survivors might benefit from reduction of blood glucose levels needs further investigation.