Spatial working memory deficits in the relatives of schizophrenic patients

BACKGROUND

Studies in nonhuman primates provide evidence that intact spatial working memory depends on the integrity of specific areas in the prefrontal cortex. Patients with schizophrenia have been shown to be impaired on spatial working memory tasks. Relatives of schizophrenic patients show a range of cognitive deficits in the absence of clinical symptoms (eg, thought disorder, eye tracking dysfunctions). We predicted that a significant proportion of relatives of schizophrenic patients would show deficits in working memory as measured by a delayed response task.

METHODS

In experiment 1, we tested 18 schizophrenic patients, 15 first-degree relatives of schizophrenic patients, and 18 normal control subjects on an oculomotor delayed response task. In experiment 2, we assessed the performance of another group of 12 first-degree relatives of schizophrenic patients and 16 different normal control subjects on a visual-manual delayed response task.

RESULTS

Relatives of schizophrenic patients showed significant deficits in working memory on both the oculomotor and visual-manual delayed response tasks.

CONCLUSIONS

Some relatives of schizophrenic patients are impaired on tasks that tap spatial working memory and that implicate the prefrontal system. The delayed response paradigm may be useful in elucidating the multidimensionality of the schizophrenic phenotype.

Structural characterization of the active site of Brucella abortus Cu-Zn superoxide dismutase: a 15N and 1H NMR investigation

Prokaryotic Cu-Zn superoxide dismutases (SODs) are rare and poorly characterized compared to their eukaryotic counterparts. To better characterize the structure of the prokaryotic enzyme, an NMR investigation of Brucella abortus Cu-Zn SOD in the reduced form was undertaken. The enzyme studied was a recombinant form, expressed in Escherichia coli. The enzyme initially lacked a full complement of Cu and Zn ion. After demetallation and remetallation with a stoichiometric amount of Cu and Zn ion, the specific activity of the recombinant B. abortus Cu-Zn SOD was comparable to the specific activity of the bovine enzyme. The 15N and 1H resonances of seven active site histidine imidazole rings were assigned using two-dimensional NMR methods. A self-consistent set of nuclear Overhauser effects between imidazole ring protons was observed, which was in agreement with the predictions of a model based on the X-ray crystallographic structure of the oxidized bovine enzyme (Tainer, J.A., Getzoff, E. D., Beem, K. M., Richardson, J.S., & Richardson, D.C. (1982) J. Mol. Biol. 160, 181-217). These observations strongly suggest that the structure of the active site of the prokaryotic enzyme is similar to that of the eukaryotic enzyme. Differences in the observed and predicted nuclear Overhauser effects could be ascribed to differences in the oxidation state of the Cu ion (Cu(I) in the reduced B. abortus enzyme and Cu(II) in the oxidized bovine enzyme), as much as they could to the different origins of the enzymes. The NMR data were also compared to a similar 1H NMR study of the human enzyme (Bertini, I., Capozzi, F., Luchinat, C., Piccioli, M., & Viezzoli, M. S. (1991) Eur. J. Biochem. 197, 691-697). The pattern of nuclear Overhauser effects and the chemical shifts of corresponding resonances were very similar in 1H NMR spectra of the human and B. abortus enzymes. Significant differences in the chemical shifts or exchange behavior of a few resonances indicated differences in the environments of several histidines in the active sites of reduced B. abortus and human Cu-Zn SODs. This is consistent with the presence of a number of insertions and deletions in the loop regions that make up the active site as indicated by amino acid sequence alignment studies. The tautomeric and protonation states of the active site histidines were also determined in this study, and the results were in agreement with previous studies. The resonances of nitrogen atoms coordinated to metal ions were found to fall between those of protonated and unprotonated nitrogens on histidine imidazoles.

Degradation of lyophilized and reconstituted MACROSCINT (DTPA-IgG): precipitation vs. glucosylation

Diethylenetriaminepentaacetic anhydride (DTPA) conjugated to IgG (DTPA-IgG) and labeled with 111In is useful for detecting focal sites of infection and inflammation (R.H. Rubin, A.J. Fischman, R.J. Callahan, B. Khaw, F. Keech, M. Ahmad, R. Wilkinson and H.W. Strauss, 111In-labeled nonspecific immunoglobulin scanning in the detection of focal infection, N. Engl. J. Med., 321 (1989) 935-940). MACROSCINT contains DTPA-IgG formulated as a lyophile from a citrate buffer containing maltose. Exposure of both reconstituted and lyophilized MACROSCINT to intense light resulted in degradation primarily via formation of precipitating aggregates. However, lyophilized and reconstituted MACROSCINT responded differently to thermal stress. Reconstituted MACROSCINT subjected to thermal stress (65 degrees C) also degraded through formation of precipitating aggregates. In contrast, exposure of lyophilized MACROSCINT to thermal stress (65 degrees C) resulted primarily in an increase in the molecular size of the MACROSCINT DTPA-IgG monomer. This increase in molecular size was a function of both the moisture content in the vial and the amount of time for which the sample was stressed, but was not a function of the conjugation with DTPA. Monosaccharide analysis of the samples demonstrated that this increase in molecular size corresponded to an increase in the amount of glucose covalently attached to the IgG. These data suggest that the increase in molecular size as a function of thermal stress is due to the covalent attachment of maltose, which is a glucose disaccharide present in the lyophile as an excipient, to the IgG. This degradation pathway was only observed in the lyophile.

Analysis of mutations of neurofibromatosis type 1 gene and N-ras gene in acute myelogenous leukemia

Neurofibromatosis type 1 (NF1) gene is a tumor suppressor gene, and the NF1 gene product, neurofibromin, can downregulate the N-ras gene. Because the N-ras gene is often mutated in acute myelogenous leukemia (AML), we wondered if the NF1 gene might be mutated in those AML samples not having N-ras mutations. We investigated the mutational status of the N-ras gene and the FLR exon of codons 1371-1423 of the open reading frame of the full-length NF1 cDNA, which has a strong homology with the mammalian ras GTPase-activating protein (GAP), especially for a stretch of three consecutive amino acids (F, L, R), by single-strand conformation polymorphism analysis and direct sequencing in samples from patients with AML. Of 48 AML patients, 10 (21%) had point (missense) mutations of the N-ras gene involving codons 12, 13 and 61. However, mutations in the FLR exon of the NF1 gene were not detected in any of the AML samples. We also examined the difference of clinical response to induction therapy between AML patients with and without N-ras mutation. A significantly lower rate of complete remission was noted in individuals with N-ras gene mutations. These results suggest that mutation of the NF1 gene, at least in the FLR exon, is very rare in AML and the NF1 gene probably is not a functional complement of the N-ras gene mutation. The presence of N-ras gene mutation may be associated with a lower clinical response to antileukemic therapy.

Biodegradable sponges for hepatocyte transplantation

Liver cell transplantation may provide a means to replace lost or deficient liver tissue, but devices capable of delivering hepatocytes to a desirable anatomic location and guiding the development of a new tissue from these cells and the host tissue are needed. We have investigated whether sponges fabricated from poly-L-lactic acid (PLA) infiltrated with polyvinyl alcohol (PVA) would meet these requirements. Highly porous sponges (porosity = 90-95%) were fabricated from PLA using a particulate leaching technique. To enable even and efficient cell seeding, the devices were infiltrated with the hydrophilic polymer polyvinyl alcohol (PVA). This reduced their contact angle with water from 79 to 23 degrees, but did not inhibit the ability of hepatocytes to adhere to the polymer. Porous sponges of PLA infiltrated with PVA readily absorbed aqueous solutions into 98% of their pore volume, and could be evenly seeded with high densities (5 x 10(7) cells/mL) of hepatocytes. Hepatocyte-seeded devices were implanted into the mesentery of laboratory rats, and 6 +/- 2 x 10(5) of the hepatocytes engrafted per sponge. Fibrovascular tissue invaded through the devices' pores, leading to a composite tissue consisting of hepatocytes, blood vessels and fibrous tissue, and the polymer sponge.

Individual differences in spatial working memory in relation to schizotypy

With a delayed-response task, spatial working memory function was assessed in normal students who were selected for schizotypy. The Wisconsin Card Sorting Test was also administered. Twenty-eight undergraduate students who scored high on the Perceptual Aberration Scale (PerAb) and 23 who scored low on this scale participated in this study. High PerAb students performed less accurately compared with the low PerAb controls on the delayed-response task, and they were more than twice as likely as low PerAb students to be impaired. The groups did not differ in the number of perseverative errors or number of categories achieved on the Wisconsin Card Sorting Test, but, as predicted, high PerAb students were less able to maintain set than were the low PerAb students. Neuropsychological implications of these data are discussed.

Insulin, but not estrogen, correlated with indexes of desaturase function in obese women

This study determined the associations of serum insulin and estrogen with fatty acid composition, fatty acid product/substrate ratios used as indexes of desaturase enzyme function, and platelet aggregation in obese and lean women. Thirty women were classified as obese (n = 8) or lean (n = 21) based on body mass index. Obese women were characterized by higher insulin levels (p < 0.05) but fasting glucose levels did not differ (p > 0.05) from lean women. Insulin positively correlated with increased C20:4n6/C18:3n6 (index of delta 5-desaturase) (p < 0.05) and C20:4n6/C18:2n6 (index of overall n6 pathway activity) (p < 0.01) in serum, and the n5 pathway in platelets (p < 0.01), but there was no correlation for insulin with platelet C18:3n6/C18:2n6 (index of delta 6-desaturase activity). Insulin was also positively related (p < 0.01) to aggregation as measured by impedance and negatively related to lag time (p < 0.05). Platelets of obese women aggregated more (p < 0.05) compared to lean women and began aggregating faster (p < 0.05), suggesting the possibility that the obese women were at greater risk for enhanced blood clotting. Plasma estrogen was correlated with age (p < 0.05) but not for other variables studied (p > 0.05). Insulin, but not estrogen, appears to influence desaturase activity, as demonstrated by increased desaturase function associated with hyperinsulinemia in obese women.

Individual differences in spatial working memory in relation to schizotypy

With a delayed-response task, spatial working memory function was assessed in normal students who were selected for schizotypy. The Wisconsin Card Sorting Test was also administered. Twenty-eight undergraduate students who scored high on the Perceptual Aberration Scale (PerAb) and 23 who scored low on this scale participated in this study. High PerAb students performed less accurately compared with the low PerAb controls on the delayed-response task, and they were more than twice as likely as low PerAb students to be impaired. The groups did not differ in the number of perseverative errors or number of categories achieved on the Wisconsin Card Sorting Test, but, as predicted, high PerAb students were less able to maintain set than were the low PerAb students. Neuropsychological implications of these data are discussed.

Purification and characterization of LasD: a second staphylolytic proteinase produced by Pseudomonas aeruginosa

We have previously described studies of a 22 kDa active fragment of the LasA proteinase. In follow-up studies of LasA, we have discovered the separate existence of a 23 kDa proteinase which shares many of the enzymatic properties of LasA, including the ability to lyse heat-killed staphylococci. However, this apparent serine proteinase, which we designate LasD, is distinct from the 22 kDa active LasA protein for the following reasons: (i) the N-terminal sequence of LasD shares no homology with LasA or the LasA precursor sequence; (ii) Pseudomonas aeruginosa LasA mutant strains AD1825 and FRD2128 do not produce LasA yet produce LasD; and (iii) specific antibodies to each proteinase do not show any cross-reactivity. LasD appears to be produced as a 30 kDa protein, which is possibly cleaved to produce a 23 kDa active fragment. The purified LasD fragment (23 kDa) shows strong staphylolytic activity only at higher pH conditions, while LasA exhibits staphylolytic activity over a broad pH range. In addition to their ability to cleave at internal diglycine sites, both the LasD and LasA endoproteinases efficiently cleave beta-casein.

Colorimetric microwell plate hybridization assay for detection of amplified Mycobacterium tuberculosis DNA from sputum samples

We developed a colorimetric microwell plate hybridization assay (CoMPHA) for the specific detection of 5'-biotinylated amplified Mycobacterium tuberculosis DNA. The optical densities of the CoMPHA corresponded to the initial amounts of purified template DNA. Here, we show that the CoMPHA is useful in distinguishing the PCR-positive and PCR-negative samples.

Surface characteristics and properties of lumbrokinase-immobilized polyurethane

Potent and novel fibrinolytic enzymes (lumbrokinase [LK]) were extracted from the earthworm, Lumbricus rubellus. These enzymes were very stable and showed greater antithrombotic activity than other currently used fibrinolytic proteins. An LK fraction showing the most potent fibrinolytic activity was immobilized onto a polyurethane (PU) surface to investigate its enzymatic activity and antithrombotic activity. A methanol-extracted PU surface was coated with 3% (wt/vol) maleic anhydride methylvinyl ether copolymer (MAMEC)/tetrahydrofuran (THF) solution, and the surface was incubated in an LK solution/phosphate-buffered saline (PBS, pH 7.4). The surface properties were characterized by attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), electron spectroscopy for chemical analysis (ESCA), and dynamic contact angle. The stability of immobilized LK was determined by caseinolytic activity assay and the specificity of immobilized LK on fibrinogen/fibrin was observed by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). The antithrombotic activity of immobilized LK was evaluated using an ex vivo rabbit A-A shunt experiment. LK immobilization was confirmed by ATR-FTIR and ESCA. Immobilized LK demonstrated stable proteolytic activity during various incubation periods. Immobilized LK proteolyzed fibrinogen and fibrin almost specifically, while it hardly hydrolyzed other plasma proteins including plasminogen and albumin. In the ex vivo A-A shunt experiment, the LK-immobilized surface significantly prolonged occlusion time over control surfaces. This is primarily due to the high thrombolytic activity of immobilized LK. In this work, a highly efficient surface modification method on the PU surface was developed, and this LK immobilization technique will be very useful in improving the blood compatibility of blood-contacting devices.

Relative effects on serum lipids and apolipoproteins of a caprenin-rich diet compared with diets rich in palm oil/palm-kernel oil or butter

Two randomized, blind studies measured changes in serum cholesterol, other serum lipids, and apolipoprotein (apo) concentrations in hypercholesterolemic men consuming caprenin (Cap)-rich diets after either baseline diets enriched in palm oil/palm-kernel oil (PO/PKO) or butter. The triglyceride Cap contains 45% 22:0 and 50% 8:0-10:0. Compared with baseline values established at 3 wk on the PO/PKO diet, the 17 subjects on the Cap diet showed significant reductions after 6 wk in HDL cholesterol (HDL-C), HDL2-C, and HDL3-C and a significant increase in the ratio of total cholesterol, LDL-C, triglycerides, apo B-100, or apo A-I were seen. Compared with baseline values established at 3 wk on the butter diet, after 6 wk the seven subjects receiving the Cap diet showed no significant changes in the lipid and apolipoprotein indexes analyzed. These data show that one or more of 8:0, 10:0, and 22:0 fatty acids can contribute to hypercholesterolemia in men.

The pattern of palatal rugae in submucous cleft palates and isolated cleft palates

The early diagnosis of submucous cleft palate is important. In children too young to tolerate nasendoscopy and videofluoroscopy the diagnosis depends on the clinical history and intraoral examination. We have studied the pattern of the hard palate rugae to investigate their possible diagnostic significance. Maxillary dental casts were obtained from 16 patients with submucous cleft palate, 17 patients with isolated clefts of the secondary palate, and 10 non-cleft controls. The hard palate mucosa had a unique feature in 14 (87.5%) of the submucous cleft palates: one or more of the palate rugae curved towards the region of the bony notch in the posterior border of the hard palate. The 2 cases without this rugae pattern did not have a detectable bony notch. In 100% of the isolated cleft palate cases, one or more of the rugae curved towards the anterior end of the cleft. This feature was not seen in any of the non-cleft controls. We consider this rugae pattern to be an additional diagnostic feature of submucous cleft palate.

Antithrombogenicity of lumbrokinase-immobilized polyurethane

Lumbrokinase is a potent fibrinolytic enzyme purified from the earthworm, Lumbricus rubellus. We immobilized 18 IU/cm2 of lumbrokinase to polyurethane using maleic anhydride methylvinyl ether copolymer (MAMEC) as an enzyme carrier, and the proteolytic and fibrinolytic activities of immobilized lumbrokinase were assayed. Immobilized lumbrokinase retained about 34% of its activity, compared with soluble lumbrokinase activity. Immobilized lumbrokinase showed stability against thermal inactivation and degradation and within a various pH range. The optimal pH of immobilized lumbrokinase shifted 1.0 pH unit upward compared with soluble enzyme. Upon exposure to the human whole blood, less amount of 125I-fibrinogen was adsorbed to lumbrokinase-immobilized surface than to the polyurethane control surface. The lumbrokinase-immobilized surface showed less platelet adhesion than did the MAMEC-grafted surface. At the early stage of platelet adhesion, the number of adhered platelets increased on the lumbrokinase-immobilized surface with increasing time; yet, the platelet number drastically decreased on the lumbrokinase-immobilized surface after 80 min incubation. This suggests that lumbrokinase-immobilized polyurethane digested the adsorbed fibrinogen and inhibited platelet adhesion on the surface, probably by inhibiting fibrinogen adsorption to be highly antithrombogenic. Clinical applications of this material to artificial organs should be developed in the near future.

Using the assessment of motor and process skills to compare occupational performance between clinic and home settings

OBJECTIVES

The study described in this article examined the effect of home versus clinic settings on the instrumental activities of daily living (IADL) performance of older adults.

METHOD

Twenty older adults living in the community were evaluated in their homes and in an occupational therapy clinic with the Assessment of Motor and Process Skills (AMPS). The motor and process ability measures were compared between the two settings with many-faceted Rasch analysis.

RESULTS

The subjects' motor ability measures tended to remain stable from clinic to home settings. The process ability measures tended not to remain stable from clinic to home settings, because 10 of the 20 subjects performed significantly better in their homes.

CONCLUSION

These findings support the idea that process skill abilities are affected by the environment to a greater degree than are motor skills abilities and that for persons living in the community, the familiar home environment tends to support IADL performance. If an occupational therapist wants to know how a person performs IADLs, the therapist should evaluate that person's performance in the environment in which the client will be functioning.

Chronic cardiac rejection masking as constrictive pericarditis

The hemodynamic changes consistent with constrictive pericarditis are often encountered in patients who have undergone cardiac transplantation. We describe here 4 patients who underwent pericardiectomy after cardiac transplantation. All were found to have evidence of a thickened and constricting peel of pericardium at surgical exploration. Their postoperative clinical courses were variable. One patient with primarily effusive constriction experienced marked improvement. Three patients failed to show clinical improvement and had persistently elevated atrial and ventricular end-diastolic pressures. A coexisting restrictive cardiomyopathy secondary to chronic rejection, coronary arteriopathy, or long-standing constriction may have been the cause of this poor outcome. Many patients with transplanted hearts exhibit evidence of poor diastolic ventricular compliance without evidence of classic constriction; some manifest both the restrictive and constrictive components. The careful selection of patients with constrictive pericarditis can optimize the outcome.

Protein kinase C association with the retinal cytoskeleton and phosphorylation of vimentin

Protein kinase C plays an important role in regulation of the cytoskeleton. We found that protein kinase C activity is associated with the retinal cytoskeleton, and that it catalyses the stoichiometric phosphorylation of two cytoskeletal proteins, with apparent molecular masses of 56 kDa and 100 kDa. The 56-kDa substrate was identified as vimentin on the basis of its apparent molecular mass, pI, solubility, immunoreactivity, pattern of proteolysis by Lys-C and a partial amino acid sequence. Immunomicroscopy was consistent with previous reports that in the retina vimentin has the unusual property of being present in neuronal cells--horizontal cells--as well as non-neuronal cells. The characteristics of protein kinase C phosphorylation of vimentin that was enriched in neuronal vimentin were determined. Hyperactivation of protein kinase C by treatment of retinas with phorbol myristate acetate resulted in the phosphorylation of vimentin in situ, indicating that the phosphorylation is physiologically relevant. In vitro, purified retinal protein kinase C catalysed the incorporation of nearly 2 mol phosphate per mole of monomeric vimentin. The phosphorylation was highly dependent on the presence of phosphatidylserine. Thus, protein kinase C functions in the retinal cytoskeleton, where a major role is in the modification of vimentin. The characterization of the phosphorylation of outer retinal vimentin by protein kinase C provides a basis for further studies on the regulation and function of this cytoskeletal element.

Identification of genetically aberrant cell lineages in Wilms' tumors

Most Wilms' tumors contain several predominant cell types, of which a primitive blastemal population is often the most prominent. Other typical components include undifferentiated mesenchymal and epithelial cells, but it has not been demonstrated that these components are neoplastic. We used a combined cytogenetic and fluorescence in situ hybridization approach to determine the clonal relationship of different cell populations within six Wilms' tumors. Clonal numerical chromosome aberrations in three Wilms' tumors were found in blastemal cells, but not in mesenchymal cells. Loss of one WT1 allele in two other tumors was detected in both blastemal and mesenchymal cells. Tetrasomy 18 in a sixth case was observed in mesenchymal and epithelial cells; blastemal cells could not be evaluated in this tumor. These findings demonstrate that mesenchymal and epithelial cells in some Wilms' tumors are neoplastic. Different histologic components in some Wilms' tumors derive from a single chromosomally aberrant ancestor which is most likely to be the primitive blastemal cell.

The effect of obesity on fibrinolytic activity and plasma lipoprotein (a) levels in patients with type 2 diabetes mellitus in Korea

To determine whether previously reported abnormalities in fibrinolytic activity and plasma lipoprotein (a) levels could reflect obesity rather than diabetes per se, plasma concentrations of tissue-type plasminogen activator (t-PA), type 1 plasminogen activator inhibitor (PAI-1), and lipoprotein (a) (Lp (a)) were investigated in sixty-four type 2 diabetic patients (56.1 +/- 9.5 years; body mass index, 24.6 +/- 3.3 kg/m2) and thirty-two control subjects (57.9 +/- 8.9 years; body mass index, 24.6 +/- 3.4 kg/m2). Both the plasma t-PA and PAI-1 antigen levels were similar between the diabetic group (10.6 +/- 3.8 ng/ml; 27.7 +/- 11.6 ng/ml) and the control group (12.2 +/- 3.5 ng/ml; 27.7 +/- 9.6 ng/ml). The PAI-1 levels were evenly distributed from 5.93 to 52.7 ng/ml in diabetic patients. The difference of Lp (a) levels between the two groups was negligible (the diabetic group, median 11 mg/dl (range 0-72 mg/dl); the control group, median 13 mg/dl (range 0-55 mg/dl)). Significant correlations between PAI-1 levels and body mass index (BMI) were observed in both groups. In the diabetic group, PAI-1 levels also correlated with fasting C-peptide levels (r = 0.54, P < 0.01) and serum triglyceride levels (r = 0.28, P < 0.05). However, we could not find a significant association between either t-PA or PAI-1 levels and Lp (a) levels in the diabetic and control groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Reconstruction of cryptotia using a skin graft

Many surgical methods have been reported for the reconstruction of cryptotia. We have devised a new modified method for surgical correction of cryptotia that uses a skin graft from the retroauricular region, and have treated 15 ears of 14 patients using this method. The method is described and cases are illustrated.

The mechanism of antiproliferative effect of desferrioxamine on human hepatoma cell lines

We investigated the effect of desferrioxamine (DFO), an iron chelator, on the DNA synthesis and the cell cycle of cultured hepatoma cells. Using Hep 3B cells as the hepatoma cell lines, DNA synthesis was measured by [3H] thymidine incorporation, and the cell cycle analysis was performed by flow cytometry including bivariate DNA/BrdU analysis. [3H] thymidine uptake was decreased by DFO in a dose dependent manner. The proportion of S phase cells increased and that of G0/G1 phase cells decreased after the addition of DFO in the culture media in a dose dependent manner up to 20 micrograms/ml of DFO. The S phase duration of the exponentially proliferating Hep 3B cells was 9.9 hours when cultured without DFO, but it was markedly prolonged (54.1 hours) after the addition of 20 micrograms/ml of DFO. After removal of DFO from the culture media following 24 hours of incubation with 20 micrograms/ml of DFO, a sequential increase from early through mid and late-S to G2/M phase was observed. In conclusion, the antiproliferative effect of DFO on cultured human hepatoma cell lines was caused by the inhibition of DNA synthesis which was related to a block in the early-mid S interface or mid S phase of the cell cycle.

Cloning of Pseudomonas fluorescens carboxylesterase gene and characterization of its product expressed in Escherichia coli

A gene (estC) coding for an esterase (esterase III) of Pseudomonas fluorescens was cloned into Escherichia coli JM83. DNA sequencing showed a single open reading frame with GTG as a translation initiation codon for esterase III. This was confirmed by N-terminal amino acid sequence analysis of the purified esterase III protein from an E. coli clone. The promoter sequence and a potential Shine-Dalgarno sequence were followed by the coding sequence of the estC gene. The amino acid sequence deduced from the nucleotide sequence contains the consensus active site sequence, G-X-S-X-G, of serine esterase. The esterase III expressed in an E. coli clone was purified by ion-exchange chromatography and gel filtration. The native form of the enzyme was a monomer with a molecular weight of 41,000. The results of substrate specificity and the inhibitor studies suggest that this enzyme is a carboxylesterase (EC 3.1.1.1) and a serine residue is present at the active site of the enzyme.

Multiple myeloma presenting as a testicular mass

Primary testicular plasmacytoma is extremely rare and only a few cases have been reported. Testicular involvement in the course of multiple myeloma is just as rare and it implies a poor prognosis, expressing an acceleration of the malignant process. We present the case of a patient with multiple myeloma presenting as a testicular mass. The literature is reviewed and testicular involvement in plasma cell neoplasms is discussed.