Acenaphthenequinone thiosemicarbazone and its transition metal complexes: synthesis, structure, and biological activity

The reaction of iron, nickel, copper, and zinc chlorides or acetates with acenaphthenequinone thiosemicarbazone, Haqtsc leads to the formation of novel complexes that have been characterized by spectroscopic studies (NMR, IR) and biological properties. The crystal structures of the free ligand Haqtsc 1 and of the compound [Ni(aqtsc)2].DMF 2, have also been determined by X-ray methods from diffractometer data. In 1, the conformation of the two nonequivalent molecules is governed by intramolecular hydrogen bonds, while an intermolecular hydrogen bond is responsible for dimer-like groups formation. In 2, the coordination geometry about nickel is distorted octahedral, and the two ligand molecules are terdentate monodeprotonated. Biological studies have shown that, for the first time at least up the used doses, a free ligand is active both in the inhibition of cell proliferation and in the induced differentiation on Friend erythroleukemia cells (FLC).

[Analgesic effects of natural growth hormone release inhibitors and their synthetic analogs. Intraspinal administration]

The authors examine the pharmacological characteristics, distribution and clinical effects of natural (somatostatin) and synthetic (octreotide) growth hormone release inhibitors (GHRIH). They mainly discuss the analgesic effect of these substances using intraspinal, epidural and subarachnoid administration. The intraspinal use of somatostatin and its synthetic analog, octreotide, are not without risks: among these, it is worth recalling the neurotoxic and vasomotor effects. Further studies may more clearly define these and other secondary effects and also the real indications for these drugs in the context of analgesics for intraspinal use. It is hypothesised that somatostatin and octreotide, owing to their analgesic capacities, may replace the intraspinal administration of opioids in a number of clearly defined clinical conditions, such as severe pain in which opioids are contraindicated.

[Prognostic value of histologic classifications of advanced stomach cancer: comparative study of Lauren's and Goseki's classifications]

Controversy exists about the prognostic value of the histological classifications of gastric cancer commonly used. Recently Goseki proposed a new classifying system based on intracellular mucus production and the degree of tubular differentiation. The aim of this study was to compare Lauren and Goseki classifications with particular emphasis on their prognostic significance. Eighty-nine patients, who underwent potentially curative resections (RO) and radical lymphadenectomy for advanced gastric cancer from September 1988 to April 1996 were analysed. Cox regression model was used to evaluate the prognostic significance of Goseki classification, Lauren classification, age, sex, type of lymphadenectomy, depth of tumour invasion (T), node metastases (N) and number of metastatic nodes. A statistically significant correlation between the different Goseki grades and histology according to Lauren was found (p < 0.001). By multivariate analysis the only parameters predictive of long term outcome were depth of tumour invasion, nodal status and histology according to the Lauren classification. Also after excluding the Lauren classification from the analysis, the Goseki histological grading system did not affect survival independently. This study on advanced gastric cancer patients identified depth of invasion, lymph node metastases and Lauren classification as significant independent pathological variables influencing survival. The classification proposed by Goseki did not add anything further to the prognostic informations provided by TNM staging and Lauren classification.

Bone marrow micrometastases in 109 breast cancer patients: correlations with clinical and pathological features and prognosis

BACKGROUND

The presence in bone marrow of cells which react with monoclonal antibodies against tumor-associated antigens has been proposed over the last few years as a new prognostic factor in breast cancer patients.

PATIENTS AND METHODS

Bone marrow aspirates were obtained from 109 stage I and II breast cancer patients during or 2-4 weeks after primary surgery. The samples were processed for leukocyte separation on a Ficoll-Hypaque gradient and then used to prepare cytospin slides for immunocytochemical analysis. The slides were stained with a pool of monoclonal antibodies (MoAbs) which recognize tumor associated antigens, using the alkaline phosphatase anti-alkaline phosphatase method. The median follow-up was 36 months (range 15-62): 22 patients relapsed and 7 died.

RESULTS

Thirty-four of the 109 patients (31.1%) had MoAb positive bone marrow cells. The bone marrow was positive in 28/74 (37.9%) patients who had the aspirate taken during surgery and in 6/35 (17.1%) who had it taken after surgery (p = 0.055). No association was found between bone marrow positivity and tumour size, nodal status, menopausal status, estrogen receptor positivity or the proliferative index. No association was found between bone marrow and prognosis: the log-rank test was 0.291 (p > 0.5) for OS and 0.023 for DFS; the hazard ratio (positive vs negative) was 1.51 for OS (95% CI: 0.33-6.86) and 0.93 for DFS (95% CI: 0.35-2.45).

CONCLUSIONS

In our series, bone marrow positivity did not correlate with prognostic parameters or prognosis. Of interest is the relative excess of positivity when the bone marrow was obtained during surgery.

Endocrine tumors of the pancreas: Ki-67 immunoreactivity on paraffin sections is an independent predictor for malignancy: a comparative study with proliferating-cell nuclear antigen and progesterone receptor protein immunostaining, mitotic index, and other clinicopathologic variables

Prediction for malignancy of pancreatic endocrine tumors (PET) is often a formidable challenge for the pathologist. The authors evaluated the role of the proliferative activity and progesterone receptor protein (PgRP) in predicting prognosis and survival of PET. Twenty-three functioning (FT) and 31 nonfunctioning tumors (NFT) were evaluated for mitotic activity and immunostaining for Ki-67 antigen, proliferating cell nuclear antigen (PCNA), and progesterone receptor protein (PgRP) on paraffin sections. The results were expressed as a percentage (index) of immunoreactive or mitosing cells. All 54 cases showed immunostaining for Ki-67 and PCNA, and valuable mitotic index, whereas only a fraction of tumors (25 of 54 cases) exhibited PgRP expression. Ki-67 and PCNA indexes correlated strongly between themselves and to mitotic index, whereas an inverse relationship was observed between cell proliferation and PgRP status in both FT and NFT. Although univariate analysis showed that Ki-67, PCNA, mitotic and PgRP indexes, stage, immunoreactivity for hormones other than insulin, diameter, and nonfunctioning type of tumor were statistically correlated to survival, Cox's regression method let only Ki-67 index emerge as an independent predictor of survival using a cutoff value of 5% in both FT and NFT.

Detection of right ventricular ischaemia during coronary surgery by means of a right precordial lead

This study was designed to determine the intra-operative incidence of right-sided ventricular ischaemia and any association with left ventricular ischaemia. In 60 patients, undergoing coronary artery bypass grafting surgery, a right-sided precordial lead V5R was used. ST segment deviation of more than 1 mm in V5R was considered significant for myocardial ischaemia. Right ventricular ischaemia occurred in 14 patients (23.3%) but was not associated with left ventricular inferior wall ischaemia. In 4 patients (6.6%) presenting with right ventricular ischaemia, ischaemia of the left inferior wall also developed but in all cases was transient and disappeared by the end of surgery. No myocardial infarction was detected in the post-operative period. The present study showed that the use of a right-sided lead may improve intra-operative electrocardiographic monitoring, by revealing ischaemia in those patients in whom ECG abnormalities were not detected by conventional leads. The transient right ventricular ischaemia recorded in this study was probably related to a reduced hypothermic protection of the right ventricle during aortic cross clamping.

Characterization of myocardial tissue in patients undergoing maintenance hemodialysis by quantitative echocardiography

The uremic state affects myocardial structure, bringing about, among other things, interstitial calcium deposition. Abnormalities of myocardial structure can be assessed quantitatively and noninvasively during life by the analysis of the gray-level distribution of conventional two-dimensional echocardiograms. The aim of this study was to evaluate the role of quantitative echocardiography in providing information on myocardial structure in patients under maintenance hemodialysis and to relate the ultrasonic findings with abnormalities in calcium-phosphate metabolism. Forty patients undergoing dialysis without abnormalities in left ventricular regional and global function and 17 hypertensive patients with comparable left ventricular hypertrophy were studied. The distribution of the gray levels within a region of interest in the interventricular septum was analyzed off-line by an array processor-based computer. Compared with hypertensive patients, patients undergoing dialysis showed a greater myocardial echogenicity (mean 92 +/- 20 versus 72 +/- 15; p = 0.004) and a reduced homogeneity of distribution of gray levels (entropy 4.5 +/- 0.2 versus 4.2 +/- 0.2, p < 0.01; uniformity 0.010 +/- 0.003 versus 0.020 +/- 0.004, p < 0.005). In the same patients, a significant negative linear relation was found between entropy and calcium-phosphate product (r = -0.66; p = 0.001). Quantitative analysis of conventional two-dimensional echocardiograms allows the detection of a pathologic myocardial structure in patients under maintenance hemodialysis with normal left ventricular function. These abnormalities are related to disorders of calcium-phosphate metabolism and bear no relationship to the degree of left ventricular hypertrophy.

[Imaging of bronchogenic cysts]

Bronchogenic cysts, unlike the other mediastinal cysts, exhibit a high incidence of complications, which makes their resection advisable even if no symptoms are present. The correct diagnosis should thus be made with the available imaging modalities. We reviewed our series of 11 bronchogenic cysts, all of them studied with conventional radiology (CR), as well as with such newer imaging modalities as CT and/or MRI. All mediastinal lesions had fluid density at CT and were homogeneously hyperintense on T2-weighted MR images. On the contrary, on T1-weighted images, some lesions were hypointense and some hyperintense, probably because of their rich protein content. In contrast, hilar or pulmonary lesions had air inside, except for one case--characterized by multiple localizations--in which the hilar lesion exhibited the same fluid density as the mediastinal lesions. The CT or MR finding of a lesion with fluid content below the carina permits a nearly unquestionable diagnosis of bronchogenic cyst since the other cystic lesions involve this region very rarely. In all the other cases, other types of mediastinal or hilar-pulmonary lesions cannot be ruled out. In particular, in case of cysts in paraesophageal site, no imaging modality permits to differentiate bronchogenic from enteric cysts; in some cases, the differential diagnosis may be impossible even with histology of the resected specimen.

[Retroperitoneal Castleman's disease. Presentation of a clinical case]

Castelman disease (CD) is a rare lymphadenopathy that usually presents as a solitary, slow growing mass; its etiology is still unknown. The authors described a case of CD localized in the retro-pancreatic space. A 33-year old patient, female, underwent abdominal ultrasonography because of upper right abdominal pain. The ultrasound showed gallbladder stones and a mass of 4 cm in diameter behind the pancreatic head, modifying the shape of the inferior vena cava. The patient underwent surgical excision and histological examination showed a hyaline type of CD. In the 70% of the cases, the disease is located in the mediastinum, only in 14% of the cases in the retroperitoneal space. The case we report is a hyaline type of CD that is the most frequent histological type, constitutes 90% of the cases, occurs usually in the young population and after surgical excision has a very good prognosis. Different is the clinical behaviour of the plasma cell type of CD that has an aggressive and often fatal clinical outcome. The patient we treated is still free of any symptoms one year after the operation.

The effects of hypertonic saline solution on coronary blood flow in anaesthetized pigs

1. The effects of intracoronary bolus infusion of hypertonic saline solution on left circumflex coronary blood flow were examined in sixteen anaesthetized and artificially ventilated pigs whilst preventing changes in heart rate and arterial blood pressure. 2. In fourteen pigs, bolus infusion of 7.5% hypertonic saline solution (2 ml within 30 s) caused a steady-state increase in coronary blood flow without significantly affecting right atrial or left ventricular pressure and its rate of rise (dP/dtmax). Infusing normal saline solution (0.9%) at the same rate and volume in seven pigs did not have this effect. 3. In five pigs, the magnitude and the duration of the response of increase in coronary blood flow were increased in a graded manner by graded increases in the concentration of the hypertonic saline solution between 2.5, 5 and 7.5%. 4. In nine pigs, the response of increase in coronary blood flow to the bolus infusion of hypertonic saline solution was not affected by the blocking agents atropine, propranolol and phentolamine, but it was completely abolished in the same nine pigs by the subsequent intracoronary administration of N omega-nitro-L-arginine methyl ester (L-NAME) which blocks the synthesis of endothelium-derived relaxing factor (EDRF) and in seven pigs by solely giving L-NAME. 5. These results showed that the intracoronary bolus infusion of hypertonic saline solution in anaesthetized pigs caused a coronary vasodilatation which involved mechanisms dependent on the release of EDRF.

Fat body of the frog Rana esculenta: an ultrastructural study

In the frog, the fat body is the largest body lipid deposit and is associated with the gonad. The aim of the present work was to investigate the fine structure of the fat body at different periods of the annual cycle and during prolonged starvation. Results indicate that fat body cells of Rana esculenta caught in autumn and after winter hibernation resemble mammalian adipocytes of white adipose tissue and contain markers of adipose tissue, such as S-100 protein and lipoproteinlipase. However, unlike mammalian adipocytes, fat body adipocytes consistently show small lipid droplets associated with their single, large lipid deposits, a lack of a definite external lamina, and the presence of cellular prolongations and spicula at their surfaces. Transmission and scanning electron microscopy in association with lanthanum tracer experiments suggest that in fat body adipocytes a vesicular-tubular system connects the cytoplasm and the interstitial space. In June (i.e., during the reproductive period), fat body adipocytes appear to have lost much of their lipid deposit and adjacent adipocytes show interdigitation of their plasma membranes and prominent Golgi complexes. In starved frogs, fat body cells can be almost devoid of lipid and in regression to a near-mesenchymal state. Nevertheless, these fat bodies still contain lipoproteinlipase activity (approximately 45% of that found in lipid-filled ones), indicating persistent adipose differentiation of the cells therein. Results presented here show that the R. esculenta fat body is an adipose organ undergoing reversible extreme changes in adipocyte fat content, which are associated with definite ultrastructural features. The fat body represents a suitable model for studying adipose tissue under different and extreme physiological conditions.

Proliferation Markers and Their Uses in the Study of Endocrine Tumors

A growing body of literature supports the view that the proliferative activity (PA) of tumor cells is an important prognostic indicator for a variety of different tumors. We examined the role of PA in diagnosis and prediction or malignancy of endocrine tumors (ETs) of pituitary gland, pancreas, thyroid, parathyroid glands, adrenal glands, paraganglia, gastroenteric tract, and lung. The data in the literature indicate that the assessment of PA is not a diagnostic indicator of malignancy especially at the individual case level, whereas it can be useful for identifying subsets of malignant tumors with different aggressiveness potential, as well as for choosing therapeutic options in metatstatic lesions. We hope that, in the near future, multiparametric approaches including PA markers, cell growth and differentiation factors, and oncogenes will yield valuable information for diagnosis and prognosis of ETs also in individual cases.

[Heart rupture at the right atrial level as the first manifestation of malignant lymphoma]

Primary heart lymphoma is an extremely rare condition and metastatic lymphomas constitute 9% of the total heart metastases. In most cases the lymphomatous involvement of the heart and/or pericardium is seen only at autopsy. It is unlikely that cardiac manifestations are the initial presentation of malignant lymphoma. We report a case of malignant lymphoma presenting with cardiac tamponade secondary to right atrial rupture.

[Evoked otoacoustic emissions using clicks in detection of deafness in young children]

Click-evoked otoacoustic emissions (EOAEs) are sounds emitted by the cochlea due to active outer hair cell contraction following stimulation of the stereocilia. The purpose of this study was to evaluate the use of testing for EOAEs as a valid auditory screening method in newborns, and 1074 healthy fullterm babies (2148 ears) with an Apgar score higher than 8 at birth were examined. EOAEs were elicited 4 days after birth and a correlation index higher than 70% represented normal response criteria. If there was no response, EOAEs and brainstem response potentials were tested at the age of one month. On the fourth day after birth. EOAEs specificity and efficiency were found to be 92.3% and 92.4% respectively, while sensitivity was 100%. Specificity and efficiency at one month were rated at 100%. The use of EOAEs offers numerous advantages over traditional auditory screening methods, thus suggesting that this technique is suitable for the mass-screening of infants.

Solid and cystic papillary neoplasm of the pancreas: a clinico-cytopathologic and immunocytochemical study of five new cases diagnosed by fine-needle aspiration cytology and a review of the literature

We report here on five new cases of solid and cystic papillary neoplasm (SCPN) of the pancreas diagnosed by fine-needle aspiration cytology (FNAC). All cytologic samples were obtained by ultrasonography, and the smears were conventionally fixed and stained. Special histochemical and immunocytochemical stains were also performed in some samples. Cytology revealed in all but one case numerous pseudopapillary structures composed of fibrovascular stalks lined with one or more layers of bland-appearing, uniform tumor cells. The tumor cells had round-to-oval euchromatic nuclei with frequently folded smooth contours and one or two small nucleoli. Their cytoplasm often contained eosinophilic, PAS-positive, and diastase-resistant inclusions. Foamy cells, psammoma bodies, blood, and cellular debris were found in the background. The criteria for the differential diagnosis versus other pancreatic lesions are discussed in some detail, as is the role of immunocytochemistry (ICC). In the literature, only 28 cases of cytologically investigated SCPN have been reported to the best of our knowledge. The most helpful criteria for the conclusive identification of SCPN by FNAC include the pseudopapillary arrangement with bland-appearing tumor cells, and, especially, the finding of acidophilic, PAS-positive, and diastase-resistant cytoplasmic granules.

Thermal balance and dialysis hypotension

Many studies have confirmed our original observation that dialysate T set at about 35 degrees C affords a better hemodynamic protection than the standard dialysate T of 37-38 degrees C. In this review we present some new data on the hemodynamic mechanism of the protective effect of cold dialysis on blood pressure. The study was based on serial assessment of the percent changes occurring during dialysis treatment in estimated stroke volume (aortic blood flow determined by Doppler echocardiography), blood volume (hemoglobinometry), arterial pressure (Dynamap), and heart rate (ECG), from which cardiac output (CO) indexes and total peripheral vascular resistances (TPVR) were derived. Of the 14 pts studied, 7 showed a drop in mean arterial pressure (MAP) of 25% or greater during standard dialysis (unstable patients). Compared with the 7 patients having more stable intradialysis MAP, unstable pts showed greater reduction in CO which was disproportionately greater than the reduction in blood volume, and a paradoxical decrease in TPVR, the difference being highly significant (p < 0.01 for both changes). When crossed-over to cold dialysis, along with a significantly lower reduction in MAP (p < 0.01) the unstable pts showed a lower decrease in CO which paralleled the reduction in blood volume, and an increase in TPVR. These changes were highly significant (p < 0.01). Data suggest that dialysis hypotension is characterized by an impaired venous return, probably due to the peripheral blood pooling (increased ratio between the 'unstressed' and 'stressed' blood volume) associated with the decrease in TPVR. Exposure of extracorporeal blood to cold dialysate favours the venous return to the heart by increasing TPVR and the 'stressed' blood volume.

Myocardial blood flow response to pacing tachycardia and to dipyridamole infusion in patients with dilated cardiomyopathy without overt heart failure. A quantitative assessment by positron emission tomography

BACKGROUND

Myocardial blood flow (MBF) impairment has been documented in advanced dilated cardiomyopathy (DCM) in which hemodynamic factors, secondary to severe ventricular dysfunction, may limit myocardial perfusion. To assess whether MBF impairment in DCM may also be present independent of hemodynamic factors, the present study was designed to quantify myocardial perfusion in patients with mild disease without overt heart failure.

METHODS AND RESULTS

Absolute regional MBF (milliliters per minute per gram) was measured by positron emission tomography and 13N-ammonia in resting conditions, during pacing-induced tachycardia, and after dipyridamole infusion (0.56 mg/kg over 4 minutes) in 22 DCM patients and in 13 healthy subjects. Patients were in New York Heart Association functional class I-II and showed depressed left ventricular (LV) ejection fraction by radionuclide angiography (35 +/- 8%; range, 21% to 48%), normal coronary angiography, and normal or moderately increased LV end-diastolic pressure (9.2 +/- 5.5 mm Hg; range, 2 to 20 mm Hg). There were no differences in arterial blood pressure, heart rate, and rate-pressure product between patients and control subjects in the three study conditions. Compared with control subjects, DCM patients had lower mean MBF at rest (0.80 +/- 0.25 versus 1.08 +/- 0.20 mL.min-1.g-1, P < .01), during atrial pacing tachycardia (1.21 +/- 0.59 versus 2.03 +/- 0.64 mL.min-1.g-1, P < .01), and after dipyridamole infusion (1.91 +/- 0.76 versus 3.78 +/- 0.86 mL.min-1.g-1, P < .01). LV MBF values were related to baseline LV end-diastolic pressure at rest (r = -.57, P < .01) and during pacing (r = -.67, P < .01) but not after dipyridamole infusion (r = .19, P = .40). Five patients had LV end-diastolic pressure > 12 mm Hg; in 4, myocardial perfusion was severely depressed both at baseline and in response to stress.

CONCLUSIONS

In patients with DCM without overt heart failure, myocardial perfusion is impaired both at rest and in response to vasodilating stimuli. The abnormalities in vasodilating capability can be present despite normal hemodynamics; progression of the disease is associated with more depressed myocardial perfusion.

Polymorphism-structure relationships of rifamexil, an antibiotic rifamycin derivative

The polymorphism of rifamexil, a rifamycin derivative, has been investigated by thermomicroscopy, differential thermal analysis (differential scanning calorimetry-thermogravimetry), IR spectroscopy, and X-ray powder diffraction. Two crystalline forms, an amorphous material, and three solvates have been studied. The crystal structures of two solvates have also been determined by single-crystal X-ray techniques. Although the overall conformation of rifamexil is very similar in the two compounds, marked differences occur between the two crystal packings, due to differences both in the mutual orientation of the molecules and in the rifamexil-solvent interactions. Multivariate statistical methods have been used to identify the principal structural parameters determining the biological activity of the rifamycins.

Detection at diagnosis of tumor cells in bone marrow aspirates of patients with small-cell lung cancer (SCLC) and clinical correlations

BACKGROUND

Immunocytochemistry has often been used to identify tumor cells in bone marrow aspirate (BMA) of SCLC patients in order to improve the results of conventional histomorphology. However, whether the detection of bone marrow microlocalisation at diagnosis had implications for prognosis has not been clear.

PATIENTS AND METHODS

Eighty-four slides (44 patients) and 66 bone marrow biopsies (from 42/44 patients) were evaluated. Cytospins of BMA were incubated with the monoclonal antibody (MAb) NCC-LU-243, recognising the cluster 1 antigen (NCAM) and then stained by the APAAP (alkaline phosphatase-anti-alkaline phosphatase) method. The relationship among BMA and PS (performance status), NSE (neuron-specific enolase), stage, survival was also studied.

RESULTS

33/84 (39%) BMA were positive for NCAM, compared with 8/66 (12%) bone marrow biopsies (p = 0.009), (17/44 and 6/42 patients, respectively). Moreover, BMA was positive for NCAM in 6/19 patients with limited disease. The presence of positive BMA did not correlate with PS, NSE or stage, but patients with positive BMA had shorter survivals than those with negative BMA (median survival: 7 and 12 months, respectively, p = 0.007).

CONCLUSIONS

Bone marrow involvement detected by immunocytochemistry appears to be related to survival but not to parameters of tumor burden (NSE, stage), suggesting that this technique might help to select patients with better prognoses for new therapeutic strategies.

Pulmonary gas exchange during orthotopic liver transplantation

The aim of this study was to evaluate the efficiency of pulmonary gas exchange during the course of liver transplantation. We studied 25 adult cirrhotic patients undergoing transplantation, performed with venovenous bypass. A significant increase in PaO2, and a significant decrease in physiological shunt and alveolar-arterial partial pressure difference were observed just before the start of venovenous bypass. These changes were probably caused by modifications in respiratory mechanics, such as an increase in functional residual capacity. There were no other respiratory changes during the anhepatic and post-anhepatic phases.

[Prevalence and severity of mitral insufficiency and arrhythmia in mitral valve prolapse]

OBJECTIVES

The purpose of this study was to assess, using Doppler-echocardiography and ambulatory electrocardiography in patients with mitral valve prolapse (MPV), the prevalence and severity of mitral regurgitation (MR) and arrhythmias.

METHODS

Two groups of patients were compared: those with thickening and redundancy of the mitral valve leaflets, chordae lengthening and dilatation of the valvular ring (anatomic MVP; n = 40) and those with the only movement anomaly detected by 2D echocardiogram (functional MVP; n = 80).

RESULTS

Significant (moderate or severe) MR was found in 4 (5%) of the 80 patients with functional MVP and in 20 (50%) of the 40 patients with anatomic MVP (p < 0.01). No significant difference in the prevalence of atrial and ventricular arrhythmias was found between patients with functional MPV without MR and 40 randomly chosen control subjects. Arrhythmias in patients with functional MVP complicated by MR were significantly more prevalent (p < 0.05) than in patients with functional MVP without MR. Patients with anatomic MVP had significantly more frequent and more complex arrhythmias than did patients with functional MVP complicated by MR (p < 0.05). There was no significant difference in the prevalence of frequent and complex ventricular arrhythmias between patients with anatomic MVP and patients with functional MVP complicated by MR of comparable hemodynamic degree.

CONCLUSIONS

These results indicate that prevalence of significant (moderate or severe) MR is higher and that frequent and complex arrhythmias are significantly more prevalent in patients with anatomic MVP. The prevalence of frequent and complex arrhythmias is similar in patients with comparable MR, whether the regurgitation is related to anatomic MVP or to functional MVP or not.

Crystallization and preliminary X-ray diffraction studies on a recombinant isopenicillin N synthase from Cephalosporium acremonium

Recombinant isopenicillin N synthase from Cephalosporium acremonium was expressed in Escherichia coli and the protein was purified. After nearly 5000 crystallization trials, the apo enzyme was crystallized by the hanging drop vapour diffusion technique, using polyethylene glycol and lithium sulphate as precipitants. Two crystal forms have been obtained with either octahedral or elongated prismatic habits. The larger octahedral crystals (0.1 mm over-all dimensions) belong to space group I4 with unit cell dimensions of a = b = 124.7 A, c = 156.9 A, and diffract X-rays to about 3.5 A resolution at synchrotrons. The crystallographic asymmetric unit contains a dimer.