The significance of ASCUS cytology in HIV-positive women

OBJECTIVE

The aim of this study was to determine the incidence and severity of dysplasia associated with a cytologic diagnosis of atypical cells of undetermined significance (ASCUS) in women infected with the human immunodeficiency virus (HIV).

METHODS

A cross-sectional analysis of cervical cytology, colposcopic impression, and cervical biopsy results was performed on 261 HIV-positive women diagnosed with ASCUS. The prevalence and grade of histologically documented cervical intraepithelial neoplasia (CIN) was determined. Patients with CD4 counts above and below 200 cells/mm(3) were compared using chi(2) analysis to determine any effect of worsening immunosuppression on the rates of associated dysplasia.

RESULTS

Seven hundred sixty-one Pap smears were performed during the study period. Two hundred nine (27%) were diagnosed as ASCUS. All patients (pts) received colposcopic evaluation. The incidence of human papilloma virus (HPV) effect, low-grade CIN (I), and high-grade CIN (II, III, and carcinoma in situ) documented by cervical biopsy, cervical conization or endocervical curettings was 40, 17, and 15%, respectively. No cases of invasive cancer were found. These results are similar to those of previous cytohistologic studies of ASCUS in HIV-untested populations. There was no significant difference in frequency or severity of CIN in pts with severe immunosuppression (P = 0.4).

CONCLUSION

A cytologic diagnosis of ASCUS in HIV-positive women identifies a group at significant risk for histologic abnormalities. The majority of pts will be diagnosed with HPV or low-grade CIN. HIV infection and severe immunosuppression do not appear to increase the frequency or severity of CIN associated with ASCUS. Given the 32% risk of associated CIN, all HIV-positive women with ASCUS cytology should undergo colposcopic evaluation.

The efficacy of cervical conization in the treatment of cervical intraepithelial neoplasia in HIV-positive women

OBJECTIVE

The aim of this study was to evaluate the efficacy of cervical conization in the treatment of CIN in HIV-positive women.

MATERIALS AND METHODS

Sixty-six HIV-positive women treated with cervical conization for CIN were stratified into four groups based on surgical margin and endocervical curetting (ECC) status (group 1: -margin/-ECC, group 2: +margin/-ECC, group 3: +margin/+ECC, group 4: -margin/+ECC). The rate of histologically proven recurrent CIN was calculated for each group and compared using chi(2) analysis. The effect of +margins, +ECC, degree of dysplasia, and CD4 count on the risk of recurrence was determined by logistic regression.

RESULTS

Forty-nine percent of patients with negative margins and negative ECC experienced recurrence, most within 36 months. There was no significant difference in recurrence rate for patients with positive margins (69.2%, P = 0.19), positive ECC (50%, P = 0.97), or positive margins and ECC (66.7%, P = 0.41) when compared to patients with complete excision of dysplasia. No significant difference in the mean CD4 count of patients with and without recurrent dysplasia (316 vs. 390 cells/mm3, P = 0.37) was observed. Logistic regression showed only degree of dysplasia in the cone specimen to have a marginally significant linear relationship with recurrence.

CONCLUSION

Cervical conization is not an effective method for eradicating CIN in HIV-positive women. Most patients will recur despite complete excision of dysplasia. Surgical margin status, ECC status, and CD4 count appear to have no effect on recurrence rate. Although multiple procedures were necessary in some patients, cone biopsy was effective in preventing progression to invasive cervical cancer in all cases.

Retroperitoneal extraosseous osteosarcoma. A case report and review of literature

Extraosseous osteogenic sarcoma is a rare and highly malignant neoplasm. A 57 year old male patient presented with a mass in the abdomen involving the left lumber region. The ultrasound and computerized tomography (CT) scan showed a large mass arising from upper pole of the left kidney. Left radical nephrectomy was performed in April 1995. Histopathology report revealed a high grade extraosseous osteogenic sarcoma. Patient was disease free for 23 months. Although the prognosis is grave, aggressive surgical treatment with adjuvant therapy helps in prolonging the survival.

Antibodies against Tityus discrepans venom do not abolish the effect of Tityus serrulatus venom on the rat sodium and potassium channels

Anti-(Tityus serrulatus + Tityus bahiensis) and anti-Tityus discrepans venom polyclonal antisera were used to investigate whether antigenic differences exist between the venoms of the Brazilian T. serrulatus and the Venezuelan T. discrepans scorpions. Both antisera recognised the toxin-containing electrophoretic fractions of their cognate venoms and also those from Tityus zulianus and Tityus trinitatis venoms on Western blots. The anti-T. discrepans antiserum reacted only weakly with T. serrulatus toxic polypeptides. The effect of T. serrulatus alpha- or beta-toxins on rat skeletal muscle Na+ channels expressed in Xenopus laevis oocytes was abolished by pre-incubating the venom with anti-(T. serrulatus + T. bahiensis) serum but not with anti-T. discrepans serum. Nor did the Brazilian or the Venezuelan sera prevent the reduction in K+ currents by T. serrulatus venom in X. laevis oocytes expressing the rat brain delayed rectifying Shaker K+ channel (Kv1.2). These results indicate that toxins from T. serrulatus and T. discrepans venoms, which primarily target mammalian Na+ channels, are antigenically distinct, although they probably share common epitopes. Our results also suggest that Na+ channel-active toxins are the immunodominant antigens of the T. serrulatus venom.

Inactivated state dependence of sodium channel modulation by beta-scorpion toxin

We have examined the effects of a beta-scorpion toxin purified from the venom of the Venezuelan scorpion Tityus discrepans, TdVIII, on heterologously expressed rat skeletal muscle Na+ channels (rSkM1). TdVIII (100 nM) produced a leftward shift in the voltage dependence of activation and reduced the peak Na+ conductance of rSkM1 channels coexpressed with the rat brain beta1 subunit in Xenopus laevis oocytes, suggesting that TdVIII is a beta-scorpion toxin. These effects did not depend on the presence of the beta1 subunit. Modification of rSkM1 activation by TdVIII could be augmented by increasing the rate of stimulation (enhanced use-dependence). Shifts in channel activation were also enhanced by introducing conditioning pulses to -10 mV, and this enhancement increased with conditioning pulse duration. On the other hand, TdVIII did not affect the activation of fast-inactivation deficient mutant Na+ channels, I1303Q/ F1304Q/M1305Q. These results suggest that modulation of rSkM1 Na+ channel gating by TdVIII depends on the toxin interacting with the inactivated state of the alpha subunit.

Lateral thyrotomy for neurilemmoma of the larynx

We present a rare case of neurilemmoma of the larynx, which was excised through a lateral thyrotomy approach with resulting restoration of laryngeal function. The advantage of the lateral thyrotomy approach for submucous tumours of the larynx is discussed.

Haemodynamic changes in patients undergoing high-risk PTCA under protection of transfemoral heart- lung machine support with centrifugal pumps

Patients with a high risk for myocardial revascularization by cardiological or surgical means can be supported during high-risk PTCA with mechanical circulatory support (supp HR-PTCA). Between November 1994 and June 1997 we performed 28 supp HR-PTCA's under protection of a heart-lung machine (HLM) with femoro - femoral cannulation under regional anesthesia. We approached 2.8+/-1.5 stenoses and 1.7+/-0.6 vessels per patient. Primary success rate was 95 percent of the treated vessels. During unloading, pulmonary artery mean pressure fell to 42+/-29% of the starting value, and LVEDP was decreased to 36+/-42%. Mechanical unloading also resulted in a significant reduction of left ventricular volumes (unloaded LVEDVI and LVESVI represent 76.8% and 76.6% of pre-unloaded values, respectively, p<0.05). All patients except one survived the procedure and could be discharged from the hospital. Femoro-femoral cardio-pulmonary bypass under regional anesthesia provides sufficient protection for high risk PTCA procedures and enables high risk patients to benefit from coronary revascularization.

Expression of genes encoding the E2 and E3 components of the Bacillus stearothermophilus pyruvate dehydrogenase complex and the stoichiometry of subunit interaction in assembly in vitro

Genes encoding the dihydrolipoyl acetyltransferase (E2) and dihydrolipoyl dehydrogenase (E3) components of the pyruvate dehydrogenase (PDH) multienzyme complex from Bacillus stearothermophilus were overexpressed in Escherichia coli. The E2 component was purified as a large soluble aggregate (molecular mass > 1 x 10(6) Da) with the characteristic 532 symmetry of an icosahedral (60-mer) structure, and the E3 as a homodimer with a molecular mass of 110 kDa. The recombinant E2 component in vitro was capable of binding either 60 E3(alpha2) dimers or 60 heterotetramers (alpha2beta2) of the pyruvate decarboxylase (E1) component (also the product of B. stearothermophilus genes overexpressed in E. coli). Assembling the E2 polypeptide chain into the icosahedral E2 core did not impose any restriction on the binding of E1 or E3 to the peripheral subunit-binding domain in each E2 chain. This has important consequences for the stoichiometry of the assembled complex in vivo. The lipoyl domain of the recombinant E2 protein was found to be unlipoylated, but it could be correctly post-translationally modified in vitro using a recombinant lipoate protein ligase from E. coli. The lipoylated E2 component was able to bind recombinant E1 and E3 components in vitro to generate a PDH complex with a catalytic activity comparable with that of the wild-type enzyme. Reversible unfolding of the recombinant E2 and E3 components in 6 M guanidine hydrochloride was possible in the absence of chaperonins, with recoveries of enzymic activities of 95% and 85%, respectively. However, only 26% of the E1 enzyme activity was recovered under the same conditions as a result of irreversible denaturation of both E1alpha and E1beta. This represents the first complete post-translational modification and assembly of a fully active PDH complex from recombinant proteins in vitro.

MR-guided procedures using contemporaneous imaging frameless stereotaxis in an open-configuration system

Frameless MR-guided procedures have had limited application using conventional closed magnets, due largely to the technical difficulties involved. As a result of in-room MR image-monitoring capabilities, new open-design magnets now allow frameless stereotaxis using contemporaneous imaging to guide more invasive procedures. We evaluate our clinical experience with this new technique. An open-design 0.2 T magnet (Siemens OPEN) combined with an in-room monitor was used for 33 frameless MR-guided procedures (aspiration cytology, biopsy, and/or treatment) in a variety of locations in the head, neck, spine, brain, pelvis, and abdomen. Success of the procedure was based on the ability to accurately position the instrument in the target region to allow biopsy and/or treatment. The open-design magnet allowed the physician to directly access the patient for frameless stereotaxis as the procedure was performed. The in-room monitor provided contemporaneous imaging feedback during the procedure for successful placement of the instrument in the target region. Twenty-eight biopsy and five treatment procedures were performed. In all cases the technique resulted in successful placement of the instrument within the target tissue to complete the procedure. MR-guided procedures using contemporaneous imaging frameless stereotaxis are possible in an open-design magnet with in-room image monitoring and offer exciting possibilities for further development.

Carbon dioxide emission from european estuaries

The partial pressure of carbon dioxide (pCO2) in surface waters and related atmospheric exchanges were measured in nine European estuaries. Averaged fluxes over the entire estuaries are usually in the range of 0.1 to 0.5 mole of CO2 per square meter per day. For wide estuaries, net daily fluxes to the atmosphere amount to several hundred tons of carbon (up to 790 tons of carbon per day in the Scheldt estuary). European estuaries emit between 30 and 60 million tons of carbon per year to the atmosphere, representing 5 to 10% of present anthropogenic CO2 emissions for Western Europe.

Knowledge and opinions about dental human health resources planning in Mexico

Dental human health resource planning (DHHRP), or manpower planning in Mexico has been plagued by fundamental contradictions. In spite of having trained a great many dentists in the past two decades, the dental health status of the population has not significantly improved. Concurrently, the relative scarcity of patients in relation to the number of practising dentists seems to be more marked, a critical issue since most dental care is delivered under private schemes. In the present investigation, 196 practising dentists in Mexico City were interviewed to establish their knowledge and opinions about DHHRP, and their views about the introduction of innovative alternatives in transforming, evaluating and planning human health resources. Concerns were: a need to examine and re-define the aims, skill content and marketability of professional training in professional practice; a lack of consensus as to how this is to be achieved; and a degree of awareness that professional practice has a limited scope in meeting the challenge of providing adequate care because of maldistribution of dentists and of limited financial resources of patients.

Telomerase activity during cardiac development

Telomerase is a ribonucleoprotein involved in maintaining telomere length in stem cells and immortal and actively dividing cells. We report here for the first time that telomerase is developmentally regulated in the normal rat heart. When we compared rat hearts at different developmental stages, we found that telomerase activity decreased to 20% of the fetal level by 5 days after birth, and was undetectable by 20 days after birth. These results indicate that the rate of cardiomyocyte proliferation decreases dramatically soon after birth in the rat. Of several non-cardiac tissues examined, telomerase activity was highest in fetal and adult rat liver, suggesting that there is an active mechanism for maintaining long telomeres in liver tissue at all stages. The disappearance of telomerase activity in the rat heart at the time that cardiomyocytes become terminally differentiated suggests that telomerase downregulation is important in the permanent withdrawal of cardiomyocytes from the cell cycle.

Role of stress echocardiography in risk stratification early after an acute myocardial infarction. EPIC (Echo Persantin International Cooperative) and EDIC (Echo Dobutamine International Cooperative) Study Groups

Resting and stress echocardiography is a 'one-stop shop', which enables a wide range of information to be collected on resting function, myocardial viability, and induced ischaemia, all of which are useful for prognostic stratification. Large scale, multicentre, prospectively collected data show the prognostic failure of resting function and inducible ischaemia, both independently and combined, which are especially effective in predicting cardiac death. The GISSI data show that the increment of risk as a result of reduction in ventricular function has a hyperbolic trend, with a relatively moderate increase in mortality for ejection fraction values between 50 and 30%, but with marked increases below 30%. The EPIC data show that the 1-year risk of cardiac death is as low as 2% in patients with negative dipyridamole stress echocardiography: it doubles if the test is positive at a high dose, and is almost four times higher if it is positive at a low dose. In the field of prognostic stratification, in the absence of carefully controlled studies, the choice between coronary angiography as the only essential study, or use of a non-invasive test to discriminate access to catheterization currently reflect alternate philosophical approaches rather than scientifically based decisions. In the invasive approach, stress echocardiography offers relief from the vicious circle of chest pain-coronary angiography revascularization. In the non-invasive and physiological approach, stress echo is capable of offering, in one sitting, an insight into the main determinants of survival: function, viability, and ischaemia.

Barbiturate anticonvulsants: a neuropsychological and quantitative electroencephalographic study

We studied 11 epileptic children aged 7 to 14 years with quantitative electroencephalographic (EEG) and neuropsychological tests, both on and off the barbiturate anticonvulsants phenobarbital and mephobarbital, comparing them to 13 controls matched for age and IQ who received testing at similar intervals. Neuropsychological tests employed were the Wechsler Intelligence Scale for Children-Revised (WISC-R), Bender-Gestalt, controlled oral word association test (COWAT), selected subtests of the Wechsler Memory Scale-Revised, Purdue Peg Board, Stroop Test, Trail Making Test, Wide Range Achievement Test-Revised, and Achenbach Behavior Rating Scale. There was no difference between on- and off-drug quantitative EEG in percentage power of any frequency band between 0.6 and 32 Hz. Neuropsychological data from all 11 subjects were analyzed with a two-factor analysis of variance with repeated measures on the time factor. The only difference from controls was on the Stroop Test. Parents reported clear behavioral changes in 6 of 11 subjects, but in 4 of these children the behavioral changes were sufficiently mild that parents chose to continue the barbiturate anticonvulsants: irritability, oppositional attitude, and overactivity were described. Mephobarbital was reported by parents to cause less severe problems than phenobarbital in subjects who had taken both barbiturate anticonvulsants. Barbiturate anticonvulsants have no effect on quantitative EEG and limited effects on neuropsychological tests in school-aged children.

Combination of melatonin and tamoxifen as a chemoprophylaxis against N-nitroso-N-methylurea-induced rat mammary tumors

The effect of melatonin (Mel) and or tamoxifen (Tam) was evaluated on a mammary tumor model induced in 50 day old female Sprague-Dawley rats by a single intraperitoneal (i.p.) injection of a direct carcinogen, N-nitroso-N-methylurea (NMU) (50 mg/kg b.wt./rat). These animals were treated with either Mel 200 microg/rat per day, orally in drinking water and/or Tam (s.c.) 60 microg/rat per week or 180 microg/rat per week. The total observation period was 300 days post-NMU administration in all the animals. The mean latency period of tumor appearance and tumor incidence was recorded. The mean latency period was significantly lengthened in all the treated groups as compared to that in the only NMU-administered rats (P < 0.001). Highly significant suppression of tumor incidence was observed in Mel + Tam180 group (P < 0.001). The other two groups i.e. Mel + Tam60, and Tam180 also showed significant suppression of tumor incidence (P < 0.01). Eight weeks after the initiation of treatment regimen, we observed marked reduction in [3H]thymidine incorporation into mammary gland DNA of Mel- and/or Tam-treated groups of animals as compared to the age-matched controls and NMU-administered rats, which correlated positively with the sparse mammary gland development seen in the whole mount preparations. The result of the combined therapy is highly promising and warrants clinical evaluation in the prophylaxis of breast carcinogenesis in humans.

Ross operation and right ventricular outflow tract reconstruction with stentless xenografts

Traditionally a homograft valve is used as a pulmonary replacement device for the Ross operation. Right ventricular outflow tract reconstruction during aortic valve replacement with an autograft was performed with stentless xenograft valves in nine patients. Hemodynamic performance is satisfying, but, long term evaluation is needed.

[Cerebral toxoplasmosis in AIDS patients, CT and MRI images and differential diagnostic problems]

Cranial computed-tomographies (CT) and magnetic resonance imaging (MRI) of 14 patients with AIDS and central nervous system toxoplasmosis (CNST) were reviewed. In spite of the low specificity of CT and MRI findings in CNS mass lesions of AIDS patients, there are some features which have been observed as more typical of CNST, namely: 94.9% of the lesions were round shaped and 94.5% had ring or nodular enhancement; 81.3% of the cases presented multiple lesions; 60.2% of the lesions were localized at the cerebral cortical or corticomedullary junction (100% of the cases showed at least 1 lesion in this localization); 34.6% of the lesions had less than 1cm in diameter.; on nonenhanced CT, 91.3% of the lesions were hypodense.; On T2-weighted MR images, 53.4% of the lesions had at least one hypointense zone on T2-weighted images. The existence of target-shaped lesions with hypointense centre on T2-weighted MR images (29.3% the observed lesions) is also suggestive of CNST, which, to our belief, had not been previously reported and will need confirmation with larger series. The visualization of iso/hyperdense lesions on nonenhanced CT or irregular shape lesions is uncommon in CNST. The finding of a solitary lesion, on CT or MR, it is not, by itself, a good criterion of differential diagnosis.

Chemoprevention by melatonin and combined melatonin-tamoxifen therapy of second generation nitroso-methylurea-induced mammary tumours in rats

Melatonin, an indole of pineal origin, is known to have an oncostatic effect on carcinogen-induced rat mammary tumours. We have assessed for the first time, the efficacy of melatonin alone and in combination with a sub-optimal dose of tamoxifen, a partial oestrogen antagonist, on N-nitroso-N-methylurea-induced rat mammary tumours. Both these agents were administered to Sprague-Dawley rats following excision of the primary tumours. Melatonin (200 micrograms/day/rat) at the given dose level could significantly suppress the appearance of second generation mammary tumours and the latency period of tumour appearance was also significantly increased (P < 0.001) as compared to vehicle-treated animals. Tamoxifen (60 micrograms/week/rat) does not suppress the development of second generation mammary tumours. Co-administration of melatonin and low dose of tamoxifen had no additive or synergistic effect on the prevention of second generation of mammary tumours. The results warrant the clinical evaluation of melatonin for chemoprevention and adjuvant therapy.

Glutathionylspermidine metabolism in Escherichia coli

Intracellular levels of glutathione and glutathionylspermidine conjugates have been measured throughout the growth phases of Escherichia coli. Glutathionylspermidine was present in mid-log-phase cells, and under stationary and anaerobic growth conditions accounted for 80% of the total glutathione content. N1,N8-bis(glutathionyl)spermidine (trypanothione) was undetectable under all growth conditions. The catalytic constant kcat/Km of recombinant E. coli glutathione reductase for glutathionylspermidine disulphide was approx. 11,000-fold lower than that for glutathione disulphide. The much higher catalytic constant for the mixed disulphide of glutathione and glutathionylspermidine (11% that of GSSG), suggests a possible explanation for the low turnover of trypanothione disulphide by E. coli glutathione reductase, given the apparent lack of a specific glutathionylspermidine disulphide reductase in E. coli.

A preliminary study of the neuropsychological heterogeneity of familial schizophrenia

This exploratory study describes the heterogeneity of the neuropsychological deficits that characterize familial schizophrenia. Forty-six familial schizophrenics showed significantly more variability in abstraction and problem-solving and motor control than 39 non-familial schizophrenics. Cluster analyses of these two neuropsychological parameters indicate that while the non-familial schizophrenics fall into one homogeneous cluster, the familial schizophrenics fall into three relatively distinct clusters which differ significantly in their morbid risk for schizophrenic-spectrum disorder. These preliminary data suggest that frontal lobe deficits are associated with an increased familial risk for schizophrenia.

[Abnormal origin of left coronary artery from pulmonary artery]

OBJECTIVE

To assess the frequency and severity of the anomalous origin of the left coronary artery (ALCA) from the pulmonary artery (PA).

DESIGN OF THE STUDY

Prospective study of case series between March 1991 and December 1994.

SETTING

Referral-based Paediatric Cardiology Department of a Tertiary Care Center.

PATIENTS AND METHODS

Five consecutive patients (pts) with anomalous origin of the LCA from the PA; there were three infants aged 4 months and two children one 8 year and one 9 year old. There were three girls and two boys. All pts had clinical and 2D-echo and Doppler investigation prior to cardiac catheterization (CC). Indication for CC was based in the association of symptoms and signs of myocarditis or dilated cardiomyopathy of acute or subacute onset and electrocardiographic (ECG) signs of ischemia in infants. In older patients (pts) diagnosis was suspected mainly from ECG. During CC in all pts, aortograms and when necessary selective coronary angiograms were performed. Surgical correction was performed in all children. In two pts stress exercise ECG and stress Thallium studies before and after surgery were performed.

RESULTS

two pts had "adult" an three had "infantile" type of ALCA from the PA. CC was performed and diagnosis was confirmed at surgery in all cases. In one child, correct diagnosis was made by ECO prior to CC and in one case LCA to PA fistula was suspected on Colour-Doppler study. No complications were attributed to CC. Several types of surgery were performed: reimplantation of the ALCA from the PA to the aorta (three pts); tunnel connection of the aorta to the ALCA via the PA (one pt) and left internal mammary to LCA anastomosis (one pt). Two infants died intraoperatively due to extensive myocardial infarction and poor left ventricular function. All the three survivors are asymptomatic after a mean follow up of 34 months. Two oldest pts are currently in New York Heart Association functional class I with normal ECG and improved myocardial perfusion on Thallium scan despite almost total occlusion of LCA at the site of implantation in the aorta as diagnosed on coronary angiogram.

CONCLUSIONS

ALCA from PA is associated with major morbidity and mortality. Diagnosis should be suspected in pts with unexplained myocardial ischemia on ECG and even more if it is associated to clinical signs of dilated cardiomyopathy or myocarditis. Careful assessment on ECO and pulsed Doppler and colour flow mapping should make the diagnosis in most cases. Although surgery can be performed based only on ECO diagnosis, we strongly advise for angiography in all cases as in our experience there are false negative diagnosis by ECO. Preoperative Thallium studies can be useful for the selection of the type of surgery as pts with very little viable myocardium will not survive the establishment of a direct systemic to coronary blood flow and may be candidates for heart transplantation.

Site-directed mutagenesis of the redox-active cysteines of Trypanosoma cruzi trypanothione reductase

The gene for trypanothione reductase from the Silvio strain of Trypanosoma cruzi has been cloned, sequenced and overexpressed in Escherichia coli using the constitutive lpp promoter on the expression plasmid pBSTNAV. Up to 13% of the total soluble protein is enzymically active trypanothione reductase with kinetic properties similar to the enzyme purified from T. cruzi. In order to assess the catalytic role of the putative active-site cysteine residues (C53 and C58), three mutant proteins have been constructed by site-directed mutagenesis substituting alanine or serine residues for cysteine; [C53A]trypanothione reductase, [C53S]trypanothione reductase and [C58S]trypanothione reductase. Although the purified, recombinant mutant proteins were catalytically inactive with NADPH and trypanothione disulphide as substrates, all showed comparable levels of transhydrogenase activity between NADPH and thio-NADP+, suggesting that the mutant proteins had correctly folded in vivo. All three mutants showed substantially different catalytic parameters for thio-NADP+ than the wild-type enzyme, presumably as a consequence of modifying the environment of the enzyme-bound flavin, thereby altering its chemical reactivity. The purified [C58S]trypanothione reductase showed spectral properties similar to the oxidised wild-type enzyme but, unlike the wild-type enzyme, did not acquire the characteristic charge-transfer complex of the EH2 form on addition of NADPH. In contrast, in the absence of NADPH both [C53A]trypanothione reductase and [C53S]trypanothione reductase showed spectral properties similar to the EH2 form of the wild-type enzyme. These data indicate that both C53 and C58 are essential for overall catalysis, with the thiolate anion of C58 interacting with the enzyme-bound FAD and C53 interacting with the disulphide substrate. These mutants should be useful in crystallographic studies of reaction intermediates which cannot be obtained with the catalytically active native enzyme.

[The acquired immunodeficiency syndrome, hypertrophic myocardiopathy and multivalvular infectious endocarditis. Apropos a clinical case]

We present a clinical case of a 33 years old young male, gypsy, intravenous drug abuser with heroine and cocaine and AIDS diagnosis. The clinical anamnesis was mainly fever and systolic heart murmur in a clinical scenario of AIDS. The two-dimensional echocardiographic study was clearly diagnostic of an hypertrophic obstructive cardiomyopathy of the left ventricle. This study showed also the presence of multiple vegetations of the mitral, aortic and pulmonic valves in a clinical setting of an acute Streptococcus Viridans infective endocarditis. In this case report we discuss the incidence of this type of multiple cardiac lesions and particularly the presence of this specific pathogenic agent in this high risk group of patients with intravenous drug abuse and systemic immunosuppression. We pointed out the rarity of these findings of left side valvular vegetations associated with this type of cardiomyopathy and the different factors related to infective endocarditis.

Patterns of neuropsychological deficit in cases of schizophrenia spectrum disorder with and without a family history of psychosis

This study was designed to identify the types of neuropsychological deficits that are unique to familial and nonfamilial forms of schizophrenia. Seventy-two patients who met Research Diagnostic Criteria for schizophrenia or schizoaffective disorder, mainly schizophrenic, were divided into two groups on the basis of the presence or absence of a family history of psychosis. The two groups were then compared for differences on six neuropsychological parameters as well as for differences in psychotic symptoms. Multivariate analyses indicated that schizophrenic patients with a family history of psychosis showed significantly higher levels of overall neuropsychological deficit and significantly greater deficits on tests of motor-control and abstraction and problem-solving. Factor analyses indicate that schizophrenic patients with a family history of psychosis show a pattern of specific neuropsychological deficits, while schizophrenic patients without a family history show a pattern of more consistent cognitive deficits. The results of this study indicate that recent-onset schizophrenic patients with and without a family history of psychosis show distinctly different patterns of neuropsychological dysfunction. These data suggest that abnormalities in the dorsolateral prefrontal cortex and nonprimary motor areas may be associated with an increased familial risk for psychotic disorder.

Household bleaches based on sodium hypochlorite: review of acute toxicology and poison control center experience

Bleaches based on solutions of sodium hypochlorite (NaOCl) are widely used in the household to disinfect and clean hard surfaces and to bleach the laundry. A review of both published and unpublished toxicological data is presented. In addition, the results of a survey of human accidents with hypochlorite bleaches by the Poison Control Centers of France, Italy, Belgium, Greece, Turkey, Spain and Portugal for the period 1989-1992 are presented. The data show that acute accidental exposure to household bleach in use or in foreseeable misuse situations results, in the great majority of the cases, in minor, transient adverse effects on health, with no permanent sequelae. Ingestion is the most frequent route of exposure, followed by inhalation of gases evolved by mixing sodium hypochlorite bleach with acid or alkaline products. All evidence presented confirms the normal safety profile of hypochlorite-based bleaches to be similar to that of other 'generally recognized as safe' household products.

[Fetal echocardiography. The results of a 3-year study]

During the last three years (July 89 to July 92), 875 fetal echocardiographic studies were performed, at a mean gestational age of 26 +/- 6.5 weeks (12 to 40 weeks), with the following main referral indications: family history of congenital heart disease 23%; advanced maternal age 13%; fetal arrhythmia 10%; amniotic fluid abnormalities 8%; fetal malformations 7%; diabetes 6%; four chamber view changes 4%. There were 15 twin pregnancies, two of them thoracopagus. The referral patterns with higher percentage of cardiac pathology were: abnormal four chamber view 56%; fetal chromosomal anomalies 50%; omphalocele 33%; twin pregnancy 33%; IUGR 29%; arrhythmias 20%. The referral patterns with lower percentage of cardiac pathology were: congenital heart disease in the family 0.2%; maternal risk 2%; amniotic fluid volume alterations 2%. The diagnosis of congenital heart disease was made in 37 fetus (4.2%), with the following most frequent: 9 cases with the atrioventricular septal defect, 5 cases with ventricular septal defect, 5 cases with hypoplastic left heart syndrome and 5 cases with tricuspid valve abnormalities. From a total of 78 referred fetal arrhythmias, 25 were confirmed, 20 being ectopic beats without structural heart disease, 3 with tachycardia, and 2 with bradycardia. One newborn with tachycardia and Ebstein's disease died, and the fetus with AV block and left atrial isomerism died in utero. The treatment and follow up of the remaining cases with heart disease are described. The whole mortality in the cases with heart pathology was 65%.(ABSTRACT TRUNCATED AT 250 WORDS)

Trypanosoma cruzi trypanothione reductase. Crystallization, unit cell dimensions and structure solution

We have reproducibly crystallized recombinant trypanothione reductase from Trypanosoma cruzi. Yellow tetragonal crystals in the shape of elongated prisms have unit cell dimensions of a = 92.8 A, c = 156.6 A, Laue symmetry of 4/m and are suitable for a detailed structural analysis. Diffraction data to 2.7 A resolution have been recorded using synchrotron radiation at the Daresbury laboratory. The structure has been solved by molecular replacement calculations using this synchrotron data and our previously determined Crithidia fasciculata enzyme structure as a search model. The space group has been identified as P4(3) with a homodimer of approximate molecular mass of 108 kDa in the asymmetric unit. Diffraction beyond 2.5 A has been recorded when large freshly grown crystals are exposed to X-rays. Refinement of the structure is in progress.

Giant cell fibroblastoma

A report of a 1 1/2-year-old male child diagnosed as a case of giant cell fibroblastoma is described and the available literature on this neoplasm is reviewed. The tumor consists of a mixture of spindle cells and multinucleated giant cells in a myxoid or collagenous background. The pathological findings and clinical course suggest that these tumors be classified with fibromatoses of childhood. Removal of the tumor with wide excision is sufficient and these patients do not require any form of chemotherapy.

Rationally designed selective inhibitors of trypanothione reductase. Phenothiazines and related tricyclics as lead structures

Trypanothione reductase, an essential component of the anti-oxidant defences of parasitic trypanosomes and Leishmania, differs markedly from the equivalent host enzyme, glutathione reductase, in the binding site for the disulphide substrate. Molecular modelling of this region suggested that certain tricyclic compounds might bind selectively to trypanothione reductase without inhibiting host glutathione reductase. This was confirmed by testing 30 phenothiazine and tricyclic antidepressants, of which clomipramine was found to be the most potent, with a K(i) of 6 microM, competitive with respect to trypanothione. Many of these compounds have been noted previously to have anti-trypanosomal and anti-leishmanial activity and thus they can serve as lead structures for rational drug design.

Tuberculosis of the pancreas: report of three cases

Three cases of pancreatic tuberculosis are described. The first patient presented with abdominal pain, weight loss, anorexia, vomiting, hepatomegaly, and mass in the head of the pancreas, on computerized tomographic (CT) scan. The second patient presented with low grade fever, anorexia, and weight loss, and was investigated for gallbladder disease. The third patient presented with obstructive jaundice and mass lesion in the head of the pancreas. Two patients underwent laparotomy for suspected pancreatic tumors. The findings of pancreatic disease was incidental during laparotomy in the second patient. The histopathology revealed caseating granuloma in all of them. The first patient responded well to treatment, and the second patient stopped treatment after 2 months and is well. The third patient is being followed. If malignancy can be ruled out, tuberculosis should be considered in relevant geographic areas, and a tissue diagnosis should be made.

Cloning and sequence analysis of the genes encoding the dihydrolipoamide acetyltransferase and dihydrolipoamide dehydrogenase components of the pyruvate dehydrogenase multienzyme complex of Bacillus stearothermophilus

A 2641-bp EcoRI fragment of DNA that encodes the C-terminal part of the dihydrolipoyl acetyltransferase (E2) component and the dihydrolipoamide dehydrogenase (E3) component of the pyruvate dehydrogenase complex of Bacillus stearothermophilus has been cloned in Escherichia coli. Its nucleotide sequence was determined. A 705-bp truncated open reading frame was located at the 5'end of the insert which, together with the 588-bp truncated open reading frame at the 3' end of another EcoRI fragment of B. stearothermophilus DNA previously cloned and sequenced [Hawkins, C. F., Borges, A. & Perham, R. N. (1990) Eur. J. Biochem. 191, 337-446], was identified as the gene, pdhC, encoding the E2 polypeptide chain. Direct sequence analysis of the purified E2 chain confirmed that the two EcoRI fragments are adjoining in the B. stearothermophilus genome. The E3 gene, pdhD, begins just 4 bp downstream from the stop codon of the pdhC gene. The amino acid sequences deduced from the pdhC and pdhD genes correspond to proteins of 427 amino acids (E2, Mr 46,265) and 469 amino acids (E3, Mr 49,193), respectively. Both genes are preceded by potential ribosome-binding sites and the E3 gene is followed by a stemloop structure characteristic of rho-independent transcription terminators. The B. stearothermophilus E2 and E3 chains exhibit substantial sequence similarity with the corresponding subunits of other 2-oxo-acid dehydrogenase multienzyme complexes. The cloning and sequence analysis described here complete the description of the gene cluster (pdhA, B, C and D) which encodes the B. stearothermophilus pyruvate dehydrogenase multienzyme complex.

Cloning and sequence analysis of the genes encoding the alpha and beta subunits of the E1 component of the pyruvate dehydrogenase multienzyme complex of Bacillus stearothermophilus

A 4175-bp EcoRI fragment of DNA that encodes the alpha and beta chains of the pyruvate dehydrogenase (lipoamide) component (E1) of the pyruvate dehydrogenase multienzyme complex of Bacillus stearothermophilus has been cloned in Escherichia coli. Its nucleotide sequence was determined. Open reading frames (pdhA, pdhB) corresponding to the E1 alpha subunit (368 amino acids, Mr 41,312, without the initiating methionine residue) and E1 beta subunit (324 amino acids, Mr 35,306, without the initiating methionine residue) were identified and confirmed with the aid of amino acid sequences determined directly from the purified polypeptide chains. The E1 beta gene begins just 3 bp downstream from the E1 alpha stop codon. It is followed, after a longer gap of 73 bp, by the start of another but incomplete open reading frame that, on the basis of its known amino acid sequence, encodes the dihydrolipoyl acetyltransferase (E2) component of the complex. All three genes are preceded by potential ribosome-binding sites and the gene cluster is located immediately downstream from a region of DNA showing numerous possible promoter sequences. The E1 alpha and E1 beta subunits of the B. stearothermophilus pyruvate dehydrogenase complex exhibit substantial sequence similarity with the E1 alpha and E1 beta subunits of pyruvate and branched-chain 2-oxo-acid dehydrogenase complexes from mammalian mitochondria and Pseudomonas putida. In particular, the E1 alpha chain contains the highly conserved sequence motif that has been found in all enzymes utilizing thiamin diphosphate as cofactor.

Isolation and characterization of toxic proteins from the venom of the Venezuelan scorpion Tityus discrepans (Karsch)

Four toxic, electrophoretically homogeneous proteins were isolated by ion-exchange chromatography on CM-cellulose-52 from the venom of the scorpion Tityus discrepans (range North Central Venezuela), named TdIV, TdV, TdVIII and TdIX. Component TdVIII, with 56 amino acid residues and mol. wt 6140 was the most toxic by i.p. injections into mice and had an intracisternal LD50 of 7.9 micrograms protein/kg body weight. Amino acid compositions of components TdIV and TdV were very similar, suggesting that they could be highly homologous proteins, although presumably contaminated one by the other. A fifth component, named TdIII, non-toxic by i.p. injections, was also isolated in homogeneous form. The i.v. and intracisternal LD50 values of the whole T. discrepans venom were 2.5 mg/kg and 16.0 micrograms/kg, respectively.

A common structural motif in thiamin pyrophosphate-binding enzymes

The amino acid sequences of a wide range of enzymes that utilize thiamin pyrophosphate (TPP) as cofactor have been compared. A common sequence motif approximately 30 residues in length was detected, beginning with the highly conserved sequence -GDG- and concluding with the highly conserved sequence -NN-. Secondary structure predictions suggest that the motif may adopt a beta alpha beta fold. The same motif was recognised in the primary structure of a protein deduced from the DNA sequence of a hitherto unassigned open reading frame of Rhodobacter capsulata. This putative protein exhibits additional homology with some but not all of the TPP-binding enzymes.

Nasopharyngeal carcinoma in India: end-result analysis (1980-1984)

One hundred fifty patients with nasopharyngeal carcinoma were treated at the Tata Memorial Hospital from January 1980 to December 1984. Lymphoepithelioma was the most common histologic subtype. Advanced disease in stages III and IV was seen in 22.66% and 72% of the patients, respectively. Complete remission was obtained in 80 of 120 patients (66.66%) with radiation alone and in 19 of 30 patients (63.3%) who received preradiation chemotherapy and radiation. Age, sex, and histology did not influence the rate of complete remission. The N0-1 nodal status group had a significantly better response of 81% and 36% survival, as compared with the N2-3 group with a 55% response and 20% survival. Only 30 of those who received radiation alone and 10 of those who received preradiation chemotherapy are disease-free for a median period of 24 months. Twenty-six relapses have occurred within a median period of 12 months. The 5-year actuarial disease-free survival is 13%. This indicates the need for an early diagnosis and combined aggressive treatment to improve survival.

Amino acid sequence analysis of the lipoyl and peripheral subunit-binding domains in the lipoate acetyltransferase component of the pyruvate dehydrogenase complex from Bacillus stearothermophilus

The pyruvate dehydrogenase multienzyme complex from Bacillus stearothermophilus comprises a structural core, composed of 60 dihydrolipoamide acetyltransferase (E2p) subunits, which binds multiple copies of pyruvate decarboxylase (E1p) and dihydrolipoamide dehydrogenase (E3) subunits. After limited proteolysis with chymotrypsin, the N-terminal lipoyl domain of E2p was excised, purified and sequenced. The residual complex, which remained assembled, was then digested with trypsin under mild conditions. This treatment promoted complete disassembly of the complex and the various components were separated by gel filtration and h.p.l.c. A folded fragment of E2p containing about 50 amino acid residues was identified as being responsible for binding the E3 subunits, although, unlike the corresponding region of the E2p or E2o chains of the pyruvate dehydrogenase or 2-oxoglutarate dehydrogenase complexes from Escherichia coli, the fragment also bound E1p molecules. Further peptide purification and sequence analysis allowed the determination of the first 211 amino acid residues of the B. stearothermophilus E2p chain, thus providing the complete primary structure of the lipoyl domain, the E1p/E3-binding domain and the regions of polypeptide chain, probably highly flexible in nature, that link the domains to each other and to the inner-core (E2p-binding) domain. Several of the proteolytically sensitive sites were also identified. The sequence of the B. stearothermophilus E2p chain shows close homology with the sequences of the E2p and E2o chains from E. coli, although significant differences in structure are apparent. Detailed evidence for the sequence of the peptides obtained by limited proteolysis and further chemical and enzymic cleavages have been deposited as Supplementary Publication SUP 50142 (11 pages) at the British Library Lending Division, Boston Spa, Wetherby, West Yorkshire LS23 6BQ, U.K., from whom copies may be obtained as indicated in Biochem. J. (1988) 249, 5.