Polymyositis--a review and follow up study of 24 cases

Twenty-four cases of polymyositis, 3 (12.5%) of them Dermatomyositis, have been treated and followed up for over 12 years. Majority (75%) were males. Inflammatory lesion was the cause in 18 (75%), collagen disease in 4 (16.7%) and malignancy in 2 (8.35%). Presenting features were fever (100%), proximal muscle weakness (95.8%) and tenderness (54.2%), facial and respiratory muscle weakness (4.2%). Raised CPK and transaminases, electromyogram abnormality and positive muscle biopsy were recorded in all. All were treated with steroids. Complication/associations noted were arthalgia (25%), dysphagia (20.6%), peripheral neuritis (8.35%), diabetes mellitus (4.2%), pulmonary fibrosis (4.2%) and malabsorption (4.2%). Fourteen cases (58%), all of inflammatory aetiology, recovered completely. Seven cases (29.2%) developed permanent atrophy of affected muscles. Cases with collagen disease and malignancy fared worse and deteriorated because of the primary disease.

Ventricular fibrillation in patients without significant structural heart disease: a multicenter experience with implantable cardioverter-defibrillator therapy

OBJECTIVES

This study was undertaken to characterize the outcome of survivors of ventricular fibrillation with no or minimal structural heart disease who received an implantable cardioverter-defibrillator.

BACKGROUND

The prognosis among survivors of ventricular fibrillation with minimal or no structural cardiac abnormalities remains unclear. Since the advent of implantable cardioverter-defibrillators, this question takes on added importance.

METHODS

This 10-center retrospective study provided information on 28 survivors of ventricular fibrillation (mean age 42 years) with minimal or no structural abnormalities who were treated with an implantable cardioverter-defibrillator.

RESULTS

Ventricular tachyarrhythmias (polymorphic in all but one patient) were induced during baseline programmed stimulation in 39% of patients. During a median 30.6-month follow-up period after implantable cardioverter-defibrillator implantation, there were no cardiac deaths and two noncardiac deaths. Sixteen patients experienced 36 shock episodes (total 88 shocks). The majority of shocks were classified as "indeterminate"; one patient received 47 "spurious" shocks during one shock episode and each of four patients received one "appropriate" shock. Ventricular arrhythmias were not inducible in any of these latter four patients.

CONCLUSIONS

Survivors of ventricular fibrillation with minimal or no structural cardiac abnormalities receiving an implantable cardioverter-defibrillator have an excellent 3-year survival rate. The occurrence, albeit infrequent, of appropriate implantable cardioverter-defibrillator shocks in this group suggests that these patients have a potential risk of recurrent cardiac arrest whose fatal outcome may be avoided by implantable cardioverter-defibrillator therapy.

Cooperativity during multiple phosphorylations catalyzed by rhodopsin kinase: supporting evidence using synthetic phosphopeptides

Rhodopsin kinase is a key component in the shutdown of visual transduction. The phosphorylation of rhodopsin's C-terminus was evaluated using synthetic peptides derived from the last 12 amino acids (337-348) as substrates and their phosphorylated counterparts as inhibitors. It was found that synthetic peptides were phosphorylated at the serine residue corresponding to Ser-343 in the primary sequence of bovine rhodopsin. The phosphopeptides were prepared by incorporating into the peptide chain a trityl-protected serine derivative at the site destined to contain the phosphoryl group. The trityl group was selectively released with 20% (v/v) dichloroacetic acid; the free hydroxyl group was then phosphitylated with di-tert-butyl N,N-diethylphosphoramidite, and the resulting phosphite derivative was oxidized with m-chloroperoxybenzoic acid. The phosphopeptides were found to have a greater affinity for the kinase compared with their nonphosphorylated counterparts; for the peptides corresponding to residues 337-348 of rhodopsin the affinity increased in the order VSKTETSQVAPA < VSKTETS[PO3H2]QVAPA < VS[PO3H2]KTETS[PO3H2]QVAPA. The results are interpreted to support the cooperativity hypotheses proposed previously [Wilden, U., & Kühn, H. (1982) Biochemistry 21, 3014-3022; Aton, B. R., Litman, B. J., & Jackson, M. L. (1984) Biochemistry 23, 1737-1741].

Comparison of cardiac pacing with drug therapy in the treatment of neurocardiogenic (vasovagal) syncope with bradycardia or asystole

BACKGROUND

The efficacy of permanent cardiac pacing in patients with neurocardiogenic (or vasovagal) syncope associated with bradycardia or asystole is not clear. We compared the efficacy of cardiac pacing with that of oral drug therapy in the prevention of hypotension and syncope during head-up tilt testing.

METHODS

Among 70 patients with a history of syncope in whom hypotension and syncope could be provoked during head-up tilt testing, 22 had bradycardia (a heart rate < 60 beats per minute, with a decline in the rate by at least 20 beats per minute) or asystole along with hypotension during testing. There were 9 men and 13 women, with a mean (+/- SD) age of 41 +/- 17 years. Head-up tilt testing was repeated during atrioventricular sequential pacing (in 20 patients with sinus rhythm) or ventricular pacing (in 2 patients with atrial fibrillation). Regardless of the results obtained during artificial pacing, all the patients subsequently had upright-tilt testing repeated during therapy with oral metoprolol, theophylline, or disopyramide.

RESULTS

During the initial tilt test, 6 patients had asystole and 16 had bradycardia along with hypotension. Despite artificial pacing, the mean arterial pressure during head-up tilt testing still fell significantly, from 97 +/- 19 to 57 +/- 19 mm Hg (P < 0.001); 5 patients had syncope, and 15 had presyncope. By contrast, 19 patients who later received only medical therapy (metoprolol in 10, theophylline in 3, and disopyramide in 6), 2 patients who received both metoprolol and atrioventricular sequential pacing, and 1 patient who received only atrioventricular sequential pacing had negative head-up tilt tests. After a median follow-up of 16 months, 18 of the 19 patients who were treated with drugs alone (94 percent) remained free of recurrent syncope or presyncope, whereas the patient treated only with permanent dual-chamber pacemaker had recurrent syncope.

CONCLUSIONS

In patients with neurocardiogenic syncope associated with bradycardia or asystole, drug therapy is often effective in preventing syncope, whereas artificial pacing is not.

Phosphorylation of solubilised dark-adapted rhodopsin. Insights into the activation of rhodopsin kinase

A protocol for the separation of phosphorhodopsin from phospho-opsin has been developed. The method takes advantage of the finding that, while 0.5% N,N-dimethyldodecylamine-N-oxide completely solubilises membrane-embedded phosphorhodopsin, at this concentration of detergent, phospho-opsin is only sparingly soluble. Phosphorhodopsin solubilised in this manner may be freed from contaminant phospho-opsin by chromatography on hydroxyapatite. Using this method, the rhodopsin-kinase-catalysed phosphorylation of photoexcited rhodopsin and native rhodopsin was studied in rod outer-segment membranes at different levels of bleaching. Prior to analysis of the phosphorylation mixture, the phosphorylated form of photoexcited rhodopsin was converted into phospho-opsin by treatment with NH2OH. It was found that, while at a 5% bleach level the amount of phosphorhodopsin produced was 15% that of phospho-opsin, at 60% bleaching the phosphorhodopsin was less than 1% of phospho-opsin. The phosphorylation reaction under different bleaching conditions was also studied in a completely soluble system (using 2% dodecyl maltoside) and the pattern of phosphate incorporation into rhodopsin versus opsin was identical to that in the membrane system. We have previously proposed that rhodopsin kinase normally exists in an inactive form and is only activated following interaction with photoexcited rhodopsin. The present work strengthens this conclusion and also shows that, following activation, the kinase preferentially phosphorylates photoexcited rhodopsin but can also act upon unbleached rhodopsin. Two possible mechanisms for the activation of the kinase are considered. From the distribution of phosphorhodopsin and phospho-opsin at different bleaching levels, the relative rates of the phosphorylation of photoexcited rhodopsin (kR*) and rhodopsin (kR) were calculated. kR*/kR values for the membrane system of 71 +/- 20 and, for the solubilised system, of 80 +/- 19 were obtained. The algebraic equation used to obtain these values highlights the fact that the ratio of the concentrations of the two substrates, photoexcited rhodopsin and rhodopsin, in a sample, determines the final distribution of phosphate between bleached and unbleached rhodopsin. This conclusion may contribute to the understanding of 'high-gain' phosphorylation observed previously.

Electrophysiologic spectrum of atrioventricular nodal behavior in patients with atrioventricular nodal reentrant tachycardia undergoing selective fast or slow pathway ablation

INTRODUCTION

The objective of this report is to delineate the atrioventricular (AV) nodal electrophysiologic behavior in patients undergoing fast or slow pathway ablation for control of their AV nodal reentrant tachycardia (AVNRT).

METHODS AND RESULTS

One hundred sixteen consecutive patients with symptomatic AVNRT were included. Twenty-two patients underwent fast pathway ablation with complete abolition of AVNRT in all and development of complete AV block in five patients. Of 17 patients with intact AV conduction postablation, 12 had demonstrated antegrade dual pathway physiology during baseline study, which was maintained in three and lost in nine patients postablation. Two patients with successful fast pathway ablation developed uncommon AVNRT necessitating a slow pathway ablation. Twenty-one patients demonstrated both common and uncommon forms of AV nodal reentry during baseline study. The earliest site of atrial activation was close to the His-bundle recording site (anterior interatrial septum) during common variety and the coronary sinus ostium (posterior interatrial septum) during the uncommon AV nodal reentry in all 21 patients. Ninety-six patients underwent successful slow pathway ablation. Among these, the antegrade dual pathway physiology demonstrable during baseline study (60 patients) was maintained in 25 and lost in 35 patients postablation.

CONCLUSION

These data suggest that: (1) dual pathway physiology may persist after successful ablation, which might be a reflection of multiple reentrant pathways in patients with AVNRT; and (2) the retrograde pathways during common and uncommon AVNRT have anatomically separate atrial breakthroughs. These findings have important electrophysiologic implications regarding the prevailing concept of the AV nodal physiology in patients with AVNRT.

Implantable cardioverter defibrillator for prevention of sudden cardiac death in patients with ventricular tachycardia and ventricular fibrillation: ICD therapy in sudden cardiac death

Among the various therapy options for survivors of ventricular tachycardia-ventricular fibrillation (VT-VF), the implantable cardioverter defibrillator (ICD) seems most promising. It reliably terminates VT-VF and thus significantly impacts sudden cardiac death (SCD) survival. It is more effective than any of the known antiarrhythmic drugs in prevention of SCD, particularly among survivors of cardiac arrest. Compared to VT surgery, the ICD therapy can be offered to a larger pool of patients and can be placed at a lower surgical risk. With proper patient selection, ICD therapy is of major benefits to its recipients since it markedly reduces the chances of VT-VF related mortality; the main cause of premature death in this population. The ICD therapy is cost effective when compared to other medical interventions and could be more so if the implant is carried out early in the course of VT-VF management.

Electrophysiological behavior of atrioventricular node after selective fast or slow pathway ablation in patients with atrioventricular nodal reentrant tachycardia

One hundred twenty consecutive patients with symptomatic atrioventricular nodal reentrant tachycardia (AVNRT) underwent catheter ablation using radiofrequency energy. Fast pathway ablation was attempted in the first 16 consecutive patients by application of radiofrequency current in the anterior and superior aspect of the tricuspid annulus. Successful results were accomplished in 13 patients, complete atrioventricular (AV) block occurred in three. One hundred four patients underwent ablation of the slow pathway in the posterior and inferior aspect of the tricuspid annulus, which was successful in 98 patients. The remaining six patients subsequently underwent a fast pathway ablation with successful results in four and AV block in two. Therefore, 102 (98%) of the last 104 patients became free of AVNRT while maintaining intact AV conduction. This study characterizes the electrophysiological properties of the residual AV node following a selective fast or slow pathway ablation.

Mechanistic studies on aromatase and related C-C bond cleaving P-450 enzymes

Some P-450 systems, notably aromatase and 14 alpha-demethylase catalyse not only the hydroxylate reaction but also the oxidation of an alcohol into a carbonyl compound as well as a C-C bond cleavage process. All these reactions occur at the same active site. A somewhat analogous situation is noted with 17 alpha-hydroxylase-17,20-lyase that participates in hydroxylation as well as C-C bond cleavage process. The C-C bond cleavage reactions catalysed by the above enzymes conform to the general equation: [formula: see text] It is argued that all three types of reaction catalyzed by these enzymes may be viewed as variations on a common theme. In P-450 dependent hydroxylation the initially formed FeIII-O-O. species is converted into FeIII-O-OH and the heterolysis of the oxygen-oxygen bond of the latter then gives the oxo-derivative for which a number of canonical structures are possible; for example FeV = O<==>(+.)FeIV = O<==>FeIV-O.. One of these, FeIV-O. behaves like an alkoxyl radical and participates in hydrogen abstraction from C-H bond to produce FeIV-OH and carbon radical. The latter is then quenched by the delivery of hydroxyl radical from FeIV-OH. The latter species may thus be regarded as a carrier of hydroxyl radical. We have proposed that the C-C bond cleavage reaction occurs through the participation of the FeIII-O-OH species that is trapped by the electrophilic property of the carbonyl compound giving a peroxide adduct that fragments to produce an acyl-carbon cleavage. Scientific developments leading up to this conclusion are considered. In the first author's views, "The study of mechanisms is not a scientific but a cultural activity. Mechanisms do not aim at an absolute truth but are intended to be a "running" commentary on the status of knowledge in a field. As the structural knowledge in a field advances Mechanisms evolve to take note of the new findings. Just as a constructive "running" commentary provides the stimulus for higher standards of performance, so Mechanisms call for better and firmer structural information from their practitioners".

Implantable cardioverter-defibrillator therapy for prevention of sudden cardiac death

Patients with known symptomatic VT or VF are at high risk for sudden cardiac death. Various therapeutic choices can be used to reduce the incidence of arrhythmic sudden cardiac death. These include beta-blockers, class I and III antiarrhythmic agents, VT focal ablations, and ICD therapy. The overall incidence of sudden cardiac death in ICD recipients is less than 2% per year, a rate of survival not achieved with any of the available antiarrhythmic agents. VT surgical therapy can produce comparable survival results, but the minimal operative mortality is higher than that with ICD therapy. In patients with noninducible VT/VF or inducible polymorphic VT, and in those refractory to or intolerant of antiarrhythmic agents and poor left ventricular function, ICD therapy may be the only realistic option.

Neurocardiogenic syncope. Diagnosis, mechanisms, and treatment

Neurocardiogenic syncope is a common medical problem that can be identified easily by history and the findings of the head-up tilt test. Depressor reflexes from the heart causing sympathetic withdrawal that, in turn, lead to peripheral vasodilatation and hypotension may have an important role in the pathogenesis of neurocardiogenic dysfunction. Once a diagnosis of neurocardiogenic syncope has been made, specific therapeutic strategies can usually prevent recurrent syncope. However, the natural history of neurocardiogenic syncope has not been studied. Double-blind placebo-controlled studies or drug withdrawal trials are needed to assess whether all patients with neurocardiogenic syncope need lifelong therapy.

Atrioventricular nodal reentrant tachycardia. Electrophysiologic characteristics, therapeutic interventions, and specific reference to anatomic boundary of the reentrant circuit

Over the past several decades there has been enormous progress in the understanding of many electrophysiologic characteristics of the AVNRT circuit. Although a great number of questions have been resolved, several pertinent issues require further investigation. Medical treatment remains the most widely used therapeutic intervention for acute or short-term management of patients with recurrent AVNRT. However, nonpharmacologic approaches, particularly transcatheter modification of the AV node, have increasingly become popular for long-term management. Radiofrequency energy has been safe and effective for transcatheter ablative techniques. It seems highly likely that in the next several years, selective transcatheter ablation of the AV nodal (slow or fast) pathway, by providing permanent cure, will become the modality of choice in symptomatic patients with AVNRT.

Gonadal dysgerminoma-seminoma associated with severe hypercalcemia

A case is reported, of a 25-year-old phenotypic female, karyotypic male patient with metastatic gonadal dysgerminoma-seminoma and severe hypercalcemic paraneoplastic syndrome. Patient manifested normal female external genitalia, vagina, uterus, and fallopian tubes but with 46 XY karyotype. Adnexal gonads were calcified. External beam radiation therapy resolved the hypercalcemic state. Exploratory laparotomy after irradiation revealed gonadoblastoma originating from dysgenetic gonads.

Xanthogranulomatous pyelonephritis: King Faisal Specialist Hospital experience

Clinicopathologic features in a series of 11 cases of xanthogranulomatous pyelonephritis are reviewed. There were seven males and four females ranging in age from 6-56 years with an average age of 34 years. The disease was unilateral in ten cases and bilateral in one. There was associated urinary tract obstruction in eight cases due to renal or ureteric stones (5), ureteric stricture (2), and carcinoma of the urinary bladder (1). Two of the patients were renal transplant recipients in which native kidneys were involved by xanthogranulomatous pyelonephritis. In one of these cases, a small renal cell carcinoma was found in one kidney along with amyloidosis involving both kidneys. Radiologic findings were mostly non-specific. These findings are briefly discussed in light of the salient features of this disease as published in the literature.

Mechanistic studies on rhodopsin kinase. Light-dependent phosphorylation of C-terminal peptides of rhodopsin

The phosphorylation of a synthetic peptide, corresponding to the C-terminal 11 amino acids of bovine rhodopsin (VII, residues 338-348), was studied under different conditions. The peptide was only phosphorylated in the presence of photoactivated rhodopsin. Using the same protocol, 12 other peptides, mapping in the rhodopsin C-terminal, were screened for their effectiveness as substrates for rhodopsin kinase. It was found that the peptides became poorer substrates with increasing length, and the best substrates comprised the most C-terminal 9-12 amino acids as opposed to other parts of the C-terminus. It was noted that the absence of the two-terminal residues Pro347 and Ala348 impaired peptide phosphorylation. The effect of the decay of metarhodopsin II on the phosphorylation of rhodopsin and the peptides was determined, and it was found that the rhodopsin and peptide phosphorylations decayed with half times of approximately 33 min and 28 min, respectively. The sites of phosphorylation on the peptides were determined and in all cases the phosphorylation was found to be predominantly on serine residues. Only the 11-residue peptide (VII, residues 338-348) contained significant threonine phosphorylation, which was about 25% that on serine residues. Cumulatively, the results suggest that Ser343 is the preferred site of phosphorylation in vitro. The reason for the poor substrate effectiveness of the larger peptides was examined by competitive experiments in which it was shown that a poorly phosphorylated larger peptide successfully inhibited the phosphorylation of a 'good' peptide substrate. The studies above support a mechanism for rhodopsin kinase that we have termed the 'kinase-activation hypothesis'. This requires that the kinase exists in an inactive form and is activated only after binding to photoactivated rhodopsin.

Vulvar sarcoma: a report of four cases

The clinical profiles of four patients with primary vulvar sarcomas are presented. Two patients had leiomyosarcoma in association with pregnancy, a third patient had a leiomyosarcoma with epithelioid elements, and a fourth had alveolar rhabdomyosarcoma. The natural history of the disease in the three leiomyosarcomas (including the case with epithelioid elements) was characterized by an indolent protracted course and frequent local recurrence, followed by distant fatal metastases. The patient with alveolar rhabdomyosarcoma is alive-with-disease. Surgery, chemotherapy, and radiotherapy achieved palliation rather than cure. Pregnancy did not seem to influence the prognosis.

Localization of the fast and slow pathways in atrioventricular nodal reentrant tachycardia by intraoperative ice mapping

BACKGROUND

Atrioventricular (AV) nodal reentrant tachycardia is classically described as a reentrant rhythm entirely contained within the compact AV node. Although the concepts of longitudinal dissociation of two intranodal pathways and a distal common pathway are accepted, the proximal portion of the circuit remains undefined. Current reports suggest that the two pathways may be separable by atrial tissue and not contained entirely within the compact node.

METHODS AND RESULTS

We used an ice mapping method to demonstrate the slow and fast pathways of the reentrant circuit and their relation to the atrial septum around the AV node. Six patients with the usual form (slow-fast) of AV nodal reentrant tachycardia were mapped during surgery. In most patients, antegrade slow pathway localization was posterior and inferior to the compact AV node along the tricuspid annulus; in two patients, it was superior along the tendon of Todaro. Retrograde fast pathway localization was anterior or superior to the compact AV node in all patients. In all patients, anatomic distinction was made between the two pathways and the compact node.

CONCLUSIONS

We conclude that no upper common pathway exists within the compact AV node in the usual type of nodal reentrant tachycardia and that the perinodal atrial tissue is a requisite part of the tachycardia circuit.

Bilateral xanthogranulomatous pyelonephritis involving native kidneys in a renal transplant recipient: association with renal cell carcinoma and amyloidosis

An unusual case of a 44-year-old male renal transplant recipient who developed bilateral xanthogranulomatous pyelonephritis (XPN) of his native kidneys is presented. Bilateral nephrectomy specimens showed classic features of XPN. In addition, there was amyloidosis involving both kidneys and a small renal cell carcinoma in the left kidney. To the best of our knowledge, such a combination of pathologic conditions in one patient has not been previously reported.

Fine-needle aspiration biopsy diagnosis of rhabdomyosarcoma: cytologic, histologic, and ultrastructural correlations

A series of 15 cases of rhabdomyosarcoma diagnosed by fine-needle aspiration biopsy (FNAB) and confirmed by histopathology is reviewed. Cytologically, the tumors were composed of a variable mixture of cells, which according to the degree of differentiation were categorized as early, intermediate, or late rhabdomyoblasts. Histologically, the tumors were divided into embryonal 9, monomorphic round cell 4, and alveolar rhabdomyosarcoma 2. Comparison of histological and cytological features revealed that embryonal types were composed mainly of early rhabdomyoblasts. Recognition of these patterns may be helpful in FNAB diagnosis of rhabdomyosarcoma.

Nonspecific reactions of a commercial enzyme-linked immunosorbent assay kit (TECRA) for detection of staphylococcal enterotoxins in foods

A staphylococcal enterotoxin visual immunoassay kit (TECRA) has recently become commercially available. Since the kit is an enzyme-linked immunosorbent assay system equipped with polyvalent antisera against staphylococcal enterotoxin types A to E (SEA to SEE) and the test is simple and rapid to perform (4 h), it has been widely used for screening purposes. In this study, the sensitivity of the kit for detection of SEA, SEB, and SEC in ham, cheese, and mushrooms was similar to those of kits based on an enzyme immunoassay and reversed passive latex agglutination: 0.75 to 1.0 ng of SEA per ml, 0.5 to 0.75 ng of SEB per ml, and 1.0 to 1.25 ng of SEC per ml. However, the TECRA kit showed nonspecific reactions with food samples contaminated by microorganisms other than Staphylococcus aureus, such as Enterobacter agglomerans, Enterobacter cloacae, Proteus mirabilis, Pseudomonas aeruginosa, and Serratia marcescens. The substance contributing to the false-positive results differed from true staphylococcal enterotoxins in that it was (i) heat labile (completely inactivated by heating for 2 min at 100 degrees C, whereas true staphylococcal enterotoxins were inactivated by about 10% with this treatment), (ii) lower in molecular weight than staphylococcal enterotoxins, and (iii) not bound to a copper chelate Sepharose gel (all of the substance remained in the unbound wash fraction, whereas staphylococcal enterotoxins were quantitatively bound to the gel). The problem of false-positive results with the TECRA kit could be resolved by heat treatment (2 min at 100 degrees C) or by cleanup procedures involving metal chelate affinity chromatography with copper chelate Sepharose for 4 h before use of the TECRA kit.

Transcatheter modification of the atrioventricular node using radiofrequency energy

120 consecutive patients with symptomatic atrioventricular nodal reentrant tachycardia (AVNRT) underwent catheter ablation using radiofrequency energy. Fast pathway ablation was attempted in the first 16 consecutive patients by application of radiofrequency current in the anterior and superior aspect of the tricuspid annulus. Successful results were accomplished in 13 patients, complete AV block occurred in three. The other 104 patients initially underwent ablation of the slow pathway in the posterior and inferior aspects of the tricuspid annulus which was successful in 98 patients. The remaining six patients subsequently underwent a fast pathway ablation with successful results in four and AV block in two. Therefore, 102 (98%) of the last 104 patients became free of AVNRT while maintaining intact AV conduction. This study demonstrates that both AV nodal conduction pathways can be selectively ablated. However, slow pathway ablation seems safer and should be considered as the first approach.

Neomycin biosynthesis: the incorporation of D-6-deoxy-glucose derivatives and variously labelled glucose into the 2-deoxystreptamine ring. Postulated involvement of 2-deoxyinosose synthase in the biosynthesis

D-[6-3H3]6-Deoxy-5-ketoglucose (10) and D-[5,6-3H2]6-deoxyglucose (11) were incorporated into neomycins B and C using a growing culture of Streptomyces fradiae. D-[6-3H]6-Deoxy-5-ketoglucose was incorporated into neomycin, as efficiently as the well established precursor D-glucose, and was found to label exclusively the 2-deoxystreptamine ring of the antibiotic. The results strengthened the previous proposals that in the formation of 2-deoxystreptamine the C-6 hydroxyl group of D-glucose is removed prior to the cyclisation reaction. Studies using the incorporation of D-[3-3H]glucose, D-[3,4-3H2]glucose and D-[5-3H]glucose into neomycin followed by the degradation of the latter established that in the biosynthesis of the 2-deoxystreptamine ring the C-4 and C-5 hydrogen atoms of glucose are removed. The loss of the C-4 hydrogen atom of the glucose is attributed to the formation of a 4-keto derivative which facilitates the removal of the C-5 hydrogen atom thus setting the stage for the expulsion of the C-6 hydroxyl group. The 5,6-olefinic intermediate formed in the process then undergoes cyclisation eventually releasing 2-deoxyinosose. The enzyme systems which participate in the conversion of D-glucose equivalent into 2-deoxyinosose may be described as 2-deoxyinosose synthase that in broad mechanistic terms resembles dehydroquinate synthase.

Fine-needle aspiration biopsy of Ki-1-positive anaplastic large-cell lymphoma

Five cases of Ki-1-positive anaplastic large-cell lymphoma diagnosed by fine-needle aspiration biopsy are reviewed, and cytologic, histologic, and ultrastructural findings in these cases are correlated. In all cases, the diagnosis of anaplastic large-cell lymphoma was suggested on the basis of the morphological appearance in aspiration smears. This diagnosis was confirmed by immunohistochemistry, which revealed strong positivity of most of the cells by Ki-1 antibody. Two of the lymphomas were T-cell type, one was B-cell type, and the remaining 2 were composed of null cells. In 2 cases, intracytoplasmic inclusions were seen in some of the tumor cells in aspiration smears. These were ultrastructurally correlated with large lysosomal bodies of variable morphology. Fine-needle aspiration combined with immunohistochemistry may be an effective technique for diagnosing this neoplasm.