Synthesis of mevalonate- and fluorinated mevalonate prodrugs and their in vitro human plasma stability.

The mevalonate pathway is essential for the production of many important molecules in lipid biosynthesis. Inhibition of this pathway is the mechanism of statin cholesterol-lowering drugs, as well as the target of drugs to treat osteoporosis, to combat parasites, and to inhibit tumor cell growth. Unlike the human mevalonate pathway, the bacterial pathway appears to be regulated by diphosphomevalonate (DPM). Enzymes in the mevalonate pathway act to produce isopentenyl diphosphate, the product of the DPM decarboxylase reaction, utilize phosphorylated (charged) intermediates, which are poorly bioavailable. It has been shown that fluorinated DPMs (6-fluoro- and 6,6,6-trifluoro-5-diphosphomevalonate) are excellent inhibitors of the bacterial pathway; however, highly charged DPM and analogs are not bioavailable. To increase cellular permeability of mevalonate analogs, we have synthesized various prodrugs of mevalonate and 6-fluoro- and 6,6,6-trifluoromevalonate that can be enzymatically transformed to the corresponding DPM or fluorinated DPM analogs by esterases or amidases. To probe the required stabilities as potentially bioavailable prodrugs, we measured the half-lives of esters, amides, carbonates, acetals, and ketal promoieties of mevalonate and the fluorinated mevalonate analogs in human blood plasma. Stability studies showed that the prodrugs are converted to the mevalonates in human plasma with a wide range of half-lives. These studies provide stability data for a variety of prodrug options having varying stabilities and should be very useful in the design of appropriate prodrugs of mevalonate and fluorinated mevalonates.

Aspiration cytology of proliferative myositis. A case report.

A case of proliferative myositis (PM) diagnosed by fine needle aspiration biopsy (FNAB) is described. A 72-year-old, white male presented with a 3.0-cm, firm, nontender mass involving the right sternocleidomastoid muscle. FNAB showed loose clusters of uniform, fibroblastlike spindle cells and admixed large, ganglion cell-like cells with eccentric nuclei, prominent nucleoli and abundant cytoplasm. The cytologic appearance of PM is characteristic, allowing exclusion of malignancy; reliable FNAB diagnosis when supported by clinical findings; and avoidance of unnecessary, radical surgery.

Tuberculous arthritis in children. Diagnosis by needle biopsy of the synovium.

In two children ages 8 months and 4 years, tuberculous synovitis of the knee was suggested by pathologic examination of synovial tissue obtained through needle biopsy. Culture of the biopsy material was positive for Mycobacterium tuberculosis in one case. In this child, the tuberculin test was negative, in the absence of anergy, at the time the child was first evaluated, and the primary lung lesion was not identified by the radiologist. Tuberculous synovitis has not previously been recognized as part of primary tuberculosis during the early weeks when the tuberculin skin test may be negative. Magnetic resonance imaging (MRI) is a sensitive modality for demonstrating joint fluid, synovial hypertrophy, and associated osteomyelitis, if present. With the increasing frequency of cases of tuberculosis in the population, greater awareness of the risk of tuberculous arthritis in childhood is important in order to recognize this unusual presentation. If negative early on, the tuberculin skin test should be repeated after 6 weeks of arthritis. A needle biopsy of the synovium is helpful and appropriate in all children with monoarticular arthritis who have a positive tuberculin skin test.

HIV-associated nephropathy--an initial presentation in an HIV-positive patient.

The lesions of HIV-associated nephropathy occur in patients with AIDS, AIDS-related complex and in individuals clinically asymptomatic for HIV infection. We report on a 35-year-old black South African woman who presented with nephrotic syndrome and renal failure. The renal biopsy appearance suggested HIV infection and this was subsequently verified. This finding emphasises the possibility that otherwise asymptomatic patients presenting with renal disease may be HIV-positive.

Low grade mucoepidermoid carcinoma ex pleomorphic adenoma. A diagnostic problem in fine needle aspiration biopsy.

We report a case of low grade mucoepidermoid carcinoma arising in a pleomorphic adenoma (ex pleomorphic adenoma) in the parotid salivary gland of a 32-year-old woman. Fine needle aspiration biopsy showed the typical biphasic pattern of pleomorphic adenoma: groups of benign-appearing epithelial cells and chondromyxoid stroma. In addition, features of low grade mucoepidermoid carcinoma were identified retrospectively, consisting of background mucin and rare mucin-containing cells. This case illustrates that the presence of background mucin and mucin-containing cells in an otherwise usual pleomorphic adenoma may indicate the presence of a well-differentiated mucoepidermoid carcinoma. In cases such as this, a definitive diagnosis should be postponed until the lesion is examined histologically.

Fine needle aspiration of lymphoblastic lymphoma. A multiparameter diagnostic approach.

Sixteen fine needle aspiration (FNA) biopsies of lymphoblastic lymphoma (LBL) that were used to either initially diagnose disease (12) or document relapse (4) were reviewed. Cellular aspirates (2 x 10(7) cells) were readily obtained for immunologic, DNA/RNA flow cytometric and immunoglobulin and/or T-cell receptor gene rearrangement studies. Cytologically, aspirates were characterized by intermediate-sized cells (9.5-18.5 microns) with fine nuclear chromatin, small, inconspicuous nucleoli, irregular nuclear contours and scant basophilic cytoplasm. Frequent mitotic figures were seen (1-14 figures per 1,000 cells). Fourteen cases demonstrated a T-cell phenotype with considerable phenotypic variability. One case demonstrated a precursor B-cell phenotype, and another demonstrated biphenotypic expression with both T-cell and myeloid differentiation. Eleven of 14 cases (79%) were positive for terminal deoxynucleotidyl transferase. Thirteen of 15 cases (87%) manifested diploid DNA content by flow cytometric analysis and were characterized by intermediate proliferative activity (S+G2M 12.7 +/- 8.7% SD) and intermediate mean RNA index (1.3 +/- .5 SD). T beta gene rearrangements were demonstrated in four of five phenotypic T-cell LBL cases analyzed, with concomitant JH gene rearrangements observed in three cases, confirming that bigenotypic rearrangements characterize some T-cell LBLs. We conclude that FNA samples are adequate for accurate characterization of LBL and may obviate the need for surgical biopsy.

Colorimetry and constant-potential coulometry determinations of transferrin-bound iron, total iron-binding capacity, and total iron in serum containing iron-dextran, with use of sodium dithionite and alumina columns.

After the parenteral administration of iron-dextran (imferon), the increased total iron concentrations in serum can be determined by atomic absorption spectroscopy and by colorimetric methods involving sodium dithionite, which reductively dissociates iron from the dextran complex. We report that constant-potential coulometry detects only about 55-70% of dextran-bound iron before dithionite reduction and variable amounts after reaction with the reducing agent. In addition, we have developed a procedure for determining transferrin-bound iron, total iron-binding capacity (TIBC), total iron, and dextran-bound iron with the Kodak Ektachem colorimetric system. In determining total serum iron, the sample is first mixed with sodium dithionite, which rapidly dissociates all dextran-bound iron, but does not remove iron from either transferrin or hemoglobin. After the mixture is applied to an Ektachem slide, transferrin-bound iron is released at pH 4 and is detected together with the iron previously bound to dextran. TIBC is determined by mixing serum with ferric citrate in moderate excess and filtering through a small alumina (Al2O3) column, which binds excess free iron and iron-dextran; the iron in the column eluate represents the TIBC. Transferrin-bound iron is determined by applying diluted serum without added ferric citrate to an alumina column and measuring the iron in the column eluate. Dextran-bound iron is equivalent to the difference between total and transferrin-bound iron. Using this method, we found that transferrin iron-binding sites are saturated in vitro by excess iron-dextran less efficiently than by ferric citrate.

CD7-positive acute leukemia lacking T cell receptor gene rearrangements and terminal deoxynucleotidyl transferase expression suggesting pre-T cell origin.

In this report, we describe a case of acute leukemia possessing a unique immunophenotype. Leukemic cells isolated from peripheral blood were analyzed by automated fluorescence-activated flow cytometry. They demonstrated the following antigen pattern: CD7+, CD38+, transferrin receptor+, HLA-DR+, common ALL antigen (CALLA)-, and terminal deoxynucleotidyl transferase (TdT)-. No expression of B cell or myeloid antigens was observed. The observed antigen pattern suggests a pre-T cell origin. In addition, the tumor cells contained germline T cell receptor beta (T beta) and gamma (T gamma) chain genes, and a germline immunoglobulin heavy chain (JH) gene. These findings support the concept that pre-T cell leukemias may demonstrate germline T beta and T gamma genes as well as lack TdT expression. In addition, our results suggest that CD7 expression may be one of the earliest events in T cell differentiation, occurring prior to both T beta an T gamma gene rearrangements, and TdT expression.

Diagnosis and management of gastrointestinal perforations in childhood dermatomyositis with particular reference to perforations of the duodenum.

Four children with dermatomyositis were recently seen with gastrointestinal perforations. The sites of perforation in the four cases were: (1) the duodenum, esophagus, and colon; (2) the duodenum; (3) the distal stomach; and (4) the traverse colon. The gastric and transverse colon perforations were intraperitoneal and easily diagnosed. The gastric perforation was treated successfully by partial gastrectomy. The patient with the colon perforation underwent exteriorization; death occurred from cerebral complications possibly related to vasculitis. Both duodenal perforations were posterior in the distal descending portion. Enzymatic dissection into the right lower quadrant produced confusing clinical and radiographic signs and extensive retroperitoneal necrosis. Successful treatment was obtained by partial gastrectomy, sump drainage of the perforation, and parenteral nutrition. Gastrointestinal perforation is a well-recognized complication of vasculitis in childhood dermatomyositis. In particular, perforations of the distal duodenum, as reported by others, are associated with delay in diagnosis and high mortality.

Spondyloarthritis and enthesopathy. Current concepts in rheumatology.

Spondyloarthritis (Sp) is newly defined as arthritis that is clinically, pathologically, and genetically related to and predisposed to ankylosing spondylitis (AS) and Reiter's syndrome (RS) rather than to rheumatoid arthritis (RA). A diagnosis of Sp does not necessarily imply arthritis of the spine and does not depend on the demonstration of roentgenographic sacroiliitis that, in this conceptualization, is recognized not as the essential hallmark, but rather merely as a diagnostic "way station" on a continuum of disease, which may (but need not necessarily) begin with RS or be complicated during its course by AS or RS. Spondyloarthritis is distinctively characterized morphologically and clinically by disproportionate inflammation at the entheses, the sites of attachment of tendons and ligaments to bone. Family history or presence of enthesopathic pain, psoriasis, inflammatory bowel disease, uveitis, recurrent urethritis, prostatitis or cervicitis, keratoderma blennorrhagicum, HLA-B27, and asymmetric pauciarticular lower lower extremity arthritis without rheumatoid factor or rheumatoid nodules suggests a diagnosis of Sp rather than RA.

Needle biopsy of the synovium of children.

While the diagnosis of juvenile rheumatoid arthritis is based on clinical criteria and does not require confirmation by synovial biopsy, biopsy is occasionally desired to exclude other diagnoses. Needle synovial biopsy of the knee may be performed on young children as an office procedure and generally provides adequate tissue for examination. In the author's clinic this procedure has replaced open biopsy of the knee of children.