Pseudoepidemic of Legionella pneumophila serogroup 6 associated with contaminated bronchoscopes

An investigation of a pseudoepidemic of Legionella pneumophila serogroup 6 contaminating bronchoalveolar lavage specimens traced the source to contaminated tap water used to rinse disinfected bronchoscopes. The problem recurred despite plumbing changes and the installation of filters in the endoscopy unit water system because of inadequate maintenance of the filters.

Sustained complete remission after incomplete chemoradiation complicated with pelvic cellulitis in a patient with recurrent cervical carcinoma

We report on a 52-year-old female patient with a bulky, recurrent cervical carcinoma involving the vagina and bladder, who developed entero-recto-vesicovaginal fistulas and sepsis with pelvic cellulitis after external radiation of 40 Gy and 2 courses of concurrent chemotherapy. Chemoradiation was interrupted and an ileostomy was performed. After recovery, no residual tumor was detectable. Thirteen months after ceasation of chemoradiation, repair of vesicovaginal and rectovaginal fistulas via posterior sagittal approach was performed. Revision of double bowel ileostomy and ileo-T-colostomy was performed 17 months later. The patient enjoyed the restoration of enteral and urinary function only temporarily. She developed rectovesical fistula and underwent an ileostomy again 6 months later. She had another episode of peritonitis and upper gastrointestinal bleeding and expired at 4 years from initiation of salvage therapy. She had no evidence of cancer recurrence during a series of laparotomies and biopsies. The dramatic regression of the tumor may be attributed to its extraordinary radiosensitivity or chemosensitivity. The acute pelvic inflammatory complications may also contribute to the tumor cell killing. The prognosis of recurrent cervical carcinoma is invariably poor except in small tumors confined to vagina. This case gives support to the efficacy of chemoradiation and the potential role of biologic therapy in treatment of this dismal disease.

Cryptococcus neoformans var. gattii infection in northern Australia: existence of an environmental source other than known host eucalypts

The 2 known host trees of Cryptococcus neoformans var. gattii, Eucalyptus camaldulensis and E. tereticornis, do not occur naturally in the 'Top End' of the Northern Territory (NT) of Australia. Nine clinical isolates of C. neoformans var. gattii from the NT were analysed by random amplification of polymorphic deoxyribonucleic acid (RAPD) and polymerase chain reaction 'fingerprinting'. Two isolates were assigned to RAPD profile VGI, previously established as the common RAPD profile. The remaining 7 were assigned to profile VGII; 6 of these isolates were recovered from individuals living in the 'Top End'. The results strongly support the existence of an alternative environmental niche for C. neoformans var. gattii, as all isolates from Eucalyptus spp. in Australia to date have been of RAPD profile VGI.

Utilization of Chinese medicine in Taiwan

This article examines the use of Chinese medicine in Taiwan. Based on a national sample survey, the authors investigated how Chinese medicine is being used and factors that are associated with its use among the Taiwanese. Results of the study suggest that Chinese medicine use among this population depends on health conditions, and that having a regular source of care for Chinese medicine as well as a preference for Chinese medicine are two predictors for its use. Policies on the integration of Chinese medicine or other traditional medicine into the modern healthcare system are recommended.

Protective immunity induced by rotavirus DNA vaccines

It is estimated that Group A rotavirus diarrhea causes as many as one million deaths per year in children worldwide, and effective vaccines will be essential for their control. Plasmid DNA vaccines encoding murine rotaviral proteins VP4, VP6, or VP7 were tested in adult BALB/c mice for their ability to induce immune responses and provide protection against rotavirus challenge. The vaccines were administered by inoculation into cells of the epidermis with an Accell gene gun. (Auragen, Inc., Middleton, WI, USA). Each vaccine elicited rotavirus-specific serum antibodies as measured by ELISA. Virus neutralizing antibodies were detected in mice receiving plasmid DNAs encoding for outer capsid proteins VP4 and VP7, but not for VP6, an inner capsid protein, and all of the vaccines generated virus-specific CTL responses. Each vaccine was effective in protecting mice against infection after homotypic rotavirus (100 ID50) challenge, showing reductions (P < 0.0002) in viral excretion measured over a 9 day period. Increased rotavirus-specific intestinal IgA antibodies were seen in vaccinated mice after rotavirus challenge, particularly in mice that received the VP6 DNA vaccine. This suggests that intracellular IgA-mediated neutralization may be involved in protective immunity induced by the VP6 DNA vaccine, and may represent a new mechanism for protection by DNA vaccines.

Detection of antibodies to Bartonella henselae in clinically diagnosed cat scratch disease

OBJECTIVE

To determine the usefulness of an indirect immunoflourescence antibody test for antibodies to Bartonella henselae in diagnosing cat scratch disease (CSD).

DESIGN AND SETTING

Retrospective case survey of 354 patients whose sera were tested for antibodies to B. henselae at Royal Perth Hospital, Perth, and the Institute of Clinical Pathology and Medical Research, Sydney. In 1994; and measurement of the background prevalence of antibodies to B. henselae.

MAIN OUTCOME MEASURES

Prevalence of antibodies to B. henselae, odds of a positive titre (> or = 64) in patients with and without specific risk factors for CSD and clinical features of the disease; prevalence of antibodies to B. henselae in randomly selected blood donors.

RESULTS

Demographic, clinical and cat contact data were available for 303 patients. Sixty-four (21.1%) had a positive titre, as did 53 of 98 (54%) patients with a history of cat contact and lymphadenopathy. This proportion increased to 62% (38 of 61 patients) in patients with a history of cat scratch or bite and to 90.3% (28 of 31) in those with cat contact, lymphadenopathy and histological evidence of granulomatous lymphadenitis. Patients who developed lymphadenopathy after cat contact were significantly more likely to have a positive titre than those without this history (odds ratio [OR], 20.8; 95% confidence interval [95% Cl], 9.6-46; P < 0.0001). Inclusion of a history of a cat scratch or bite significantly raised the odds of being seropositive (OR, 13.7; 95% Cl, 6.8-28.1; P < 0.0001), and the presence of granulomas on lymph node biopsy further increased the odds (OR, 124.4; 95% Cl, 19.4-1073; P < 0.0001). The prevalence of antibodies to B. henselae in random blood donors in New South Wales was about 5% (five of 102 sera samples).

CONCLUSIONS

The immunofluorescence antibody test for B. henselae can be expected to be positive in just over half the patients with clinically suspected CSD, and it has a positive predictive value of 83%. In a significant number of cases the diagnosis cannot be made on the basis of the results of immunofluorescence antibody testing alone and further investigations, including lymph node biopsy, may be required.

A study of the binding of merocyanine 540 to myeloid leukemia M1 cells using an intensified charge-coupled device for fluorescence imaging microscopy

The binding of merocyanine 540 (MC540) to murine myeloid leukemia (M1) cells and normal erythrocytes was measured by fluorescence digital imaging microscopy using an intensified charge-coupled device. It was found that, on average, about three times more MC540 were bound to a unit membrane area of M1 cells than erythrocytes, a result consistent with previous studies. However, it was shown for the first time that MC540 binding varied significantly from one M1 cell to the next, and about 15% of the sensitized M1 cells were as MC540-negative as normal erythrocytes. Using the leukemic inhibitory factor as a differentiation inducer, M1 cells were induced to differentiate into mature macrophage-like cells in vitro. Such treatment lowered the average MC540 binding by about one-third but did not affect the cell-to-cell variation significantly.

Factors that predict metastasis of papillary and follicular thyroid cancers in Taiwan

The purpose of this study is to explore the relationship of postoperative thyroglobulin level and other clinical factors with tumor metastasis. Analysis of 281 pathologic lesions verified patients with papillary and follicular thyroid cancer who received their primary treatment at Chang Gung Memorial Hospital. Clinical information-including postoperative thyroglobulin levels, age, sex, primary tumor size, clinical staging, surgical methods, surgical findings, chest x-ray findings, and 131I uptake-were stored in the computer. Actual survival rate and univariate and multivariate analyses of these factors with the relationship of distant metastases were undertaken. Twenty-three patients in this study died of distant metastases from the thyroid cancer. Of these patients, 30.4% were older than 60 years. In contrast only 8.5% of patients in the survival group were older than 60 years (p < 0.05 in chi2). All of the papillary thyroid cancer patients with distant metastases displayed thyroglobulin levels higher than 25 ng/ml, but only 24% (41 of 173 cases) of those without distant metastases had thyroglobulin levels higher than 25 ng/ml. In 12 follicular thyroid cancer patients with distant metastases, 11 patients' serum thyroglobulin levels were higher than 25 ng/ml. In contrast, only 7 of 33 patients with follicular thyroid cancer without distant metastases displayed similar thyroglobulin levels. Univariate analysis revealed that age, postoperative thyroglobulin levels, chest x-ray findings, pathologic type, and tumor size are associated with distant metastases. One-month postoperative serum thyroglobulin level could be used as a prognostic factor for papillary and follicular thyroid cancer patients with distant metastases.

Factors that Predict Metastasis of Papillary and Follicular Thyroid Cancers in Taiwan

The purpose of this study is to explore the relationship of postoperative thyroglobulin level and other clinical factors with tumor metastasis. Analysis of 281 pathologic lesions verified patients with papillary and follicular thyroid cancer who received their primary treatment at Chang Gung Memorial Hospital. Clinical information—including postoperative thyroglobulin levels, age, sex, primary tumor size, clinical staging, surgical methods, surgical findings, chest x-ray findings, and 131I uptake—were stored in the computer. Actual survival rate and univariate and multivariate analyses of these factors with the relationship of distant metastases were undertaken. Twenty-three patients in this study died of distant metastases from the thyroid cancer. Of these patients, 30.4% were older than 60 years. In contrast only 8.5% of patients in the survival group were older than 60 years (p < 0.05 in χ 2 ). All of the papillary thyroid cancer patients with distant metastases displayed thyroglobulin levels higher than 25 ng/ml, but only 24% (41 of 173 cases) of those without distant metastases had thyroglobulin levels higher than 25 ng/ml. In 12 follicular thyroid cancer patients with distant metastases, 11 patients' serum thyroglobulin levels were higher than 25 ng/ml. In contrast, only 7 of 33 patients with follicular thyroid cancer without distant metastases displayed similar thyroglobulin levels. Univariate analysis revealed that age, postoperative thyroglobulin levels, chest x-ray findings, pathologic type, and tumor size are associated with distant metastases. One-month postoperative serum thyroglobulin level could be used as a prognostic factor for papillary and follicular thyroid cancer patients with distant metastases.

The interaction between human cytomegalovirus immediate-early gene 2 (IE2) protein and heterogeneous ribonucleoprotein A1

Human cytomegalovirus (HCMV) is an ubiquitous pathogen which causes significant illness in immunocompromised individuals. The immediate-early gene 2 (IE2) protein of HCMV plays an important role in the regulation of virus replication. Previous studies have shown that the IE2 protein is able to interact with several cellular proteins, but many of the IE2 interacting partners remain unidentified. By utilizing the yeast two-hybrid system, the heterogeneous ribonucleoprotein A1 (hnRNP A1) was identified as an IE2 interacting protein. The interaction was confirmed via the in vitro binding of bacterial expressed glutathione S-transferase (GST) IE2 fusion protein with the in vitro translated hnRNP A1. The mutational analysis showed that both the N-terminal half (1-290 residues) and C-terminal half (291-579 residues) of IE2 protein can interact with the hnRNP A1, indicating that more than one region of IE2 protein are involved in the binding with hnRNP A1.

Efficacy of organ preservation media enriched with nonlactate-generating substrate for maintaining tissue viability: a transplantation study

BACKGROUND

Previously, isotonic solution (IS) enriched with beta-hydroxybutyrate, a nonlactate-generating substrate, was shown to be efficacious in maintaining tissues' ATP and metabolic activity under cold storage. The objective of this study was to verify these findings in terms of tissue viability in vivo.

METHODS

Using a rabbit cornea transplantation model, efficacy of IS was studied and compared with McCarey-Kaufman medium, with or without beta-hydroxybutyrate, and other known media (Optisol and Likorol), with different properties and without beta-hydroxybutyrate. After storage at 4 degrees C for 6, 7, and 11 days, the corneas were grafted, and postoperative changes in corneal thickness, and endothelial cell density and morphology were monitored with a pachymeter and specular microscope.

RESULTS

The experiments revealed that before grafting, IS effectively controlled tissue swelling for 7 days or longer, comparable to Optisol. When grafted, the IS-stored corneas deturgesced at high rates, with a short half-time (t1/2) for the de-swelling process, and the grafts remained thin and clear with an intact endothelium. This reflects excellent tissue viability. In the controls, the deturgescence process was extremely sluggish, with significantly lower rates and longer t1/2 (P= >0.01-0.05). Immediate swelling for 3-5 days after grafting was also observed with Optisol. These grafts had significant endothelium cell loss of 24-30% after 12 weeks (P= >0.01-0.02).

CONCLUSIONS

IS is more efficacious than currently used media for sustaining the viability of donor corneas under cold storage. These findings may serve as a useful basis for future tests of IS in other organ storage systems.

Competitive inhibition of the glycine-induced current by pregnenolone sulfate in cultured chick spinal cord neurons

The effect of the neurosteroid pregnenolone sulfate (PS) on the glycine receptor-mediated response was studied in cultured chick spinal cord neurons using the whole-cell voltage-clamp recording technique. PS rapidly and reversibly inhibits the glycine-induced current in a dose-dependent manner, with an EC50 of 3.7 microM and a maximal inhibition of 100%. The fact that antagonism of the glycine response by PS is neither voltage- nor agonist-dependent indicates that PS does not act as an open-channel blocker. Furthermore, inhibition by PS of the glycine-induced current appears to be of a competitive type since the drug induces a parallel, rightward shift of the glycine dose-response curve.

Hepatic focal nodular hyperplasia: findings on color Doppler ultrasound

BACKGROUND

We assessed the color Doppler ultrasound (US) findings in focal nodular hyperplasia (FNH).

METHODS

Seven FNH lesions were imaged with color Doppler US and hepatic angiography.

RESULTS

In four lesions, color Doppler demonstrated a central stellate vascular appearance which correlated with central feeding artery with spoke-wheel sign angiographically. Except for one lesion, color Doppler US imaging correlated with angiographic findings.

CONCLUSIONS

Color Doppler US is capable of demonstrating the typical findings of a central feeding artery and stellate vascular pattern in many cases of FNH.

Pancreaticojejunal anastomotic leak after pancreaticoduodenectomy--multivariate analysis of perioperative risk factors

The records of 131 consecutive patients with periampullary carcinoma who underwent pancreaticoduodenectomy within a 12-year period were reviewed to determine the perioperative risk factors of pancreaticojejunal (PJ) anastomotic leak. Twenty-one PJ leaks were identified, for a frequency of 16% (21 of 131); 19% (4 of 21) of these patients eventually died of PJ leak-related complications. A total of 23 items of perioperative data, presumed as risk factors predisposing to PJ leak, were examined. By univariate analysis, advanced age, prolonged duration of untreated jaundice, deep jaundice, decreased creatinine clearance, increased intraoperative blood loss, and shock during operation were statistically significant. However, by multivariate analysis, only duration of jaundice, creatinine clearance, and intraoperative blood loss turned out to be independent risk factors. Noteworthily, jaundiced patients with impaired creatinine clearance not only had a higher incidence of PJ leak, but were also more liable to experience sepsis and intraabdominal bleeding, which uniformly elicited a grave clinical course. Routine preoperative biliary drainage failed to enhance the security of PJ. Completion pancreatectomy continued to carry a poor prognosis, and should be avoided when possible and replaced by early, aggressive radiologic intervention.

Identification of extracellular phospholipase B, lysophospholipase, and acyltransferase produced by Cryptococcus neoformans

We recently identified phospholipase activity as a potential virulence factor of Cryptococcus neoformans. We have now defined the nature of the phospholipase activity produced by a clinical isolate of C. neoformans var. neoformans, under native conditions, by 1H and 31P nuclear magnetic resonance (NMR) spectroscopy and thin-layer chromatography (TLC) of radiolabelled substrates. Glycerophosphocholine was identified by NMR spectroscopy as the sole phospholipid degradation product of the reaction between substrate phosphatidylcholine (PC) and cryptococcal culture supernatants indicating the presence of phospholipase B (PLB). No lysophosphatidylcholine (lyso-PC) or products indicative of phospholipase C, phospholipase D, or other lipase activity were identified. Use of PC and lyso-PC containing radiolabelled acyl chains and separation of products by TLC confirmed the PLB and lysophospholipase (LPL) activities. Lysophospholipase transacylase (LPTA) activity was identified by the formation of radioactive PC from lyso-PC. Extracellular enzyme production was maximal after 6 to 10 h in fresh medium. Assay conditions were optimized for pH, linearity with time, enzyme concentration, and saturation by substrates to allow comparison with phospholipases from other organisms. LPL activity was 10- to 20-fold greater than PLB activity, with mean (+/- standard deviation) specific activities of 34.9 +/- 7.9 and 3.18 +/- 0.2 micromol of substrate hydrolyzed per min per mg of protein, respectively. The response of PLB to increasing substrate concentrations was bimodal, whereas inhibition of LPL and LPTA activities occurred at concentrations of substrate lyso-PC greater than 200 microM. Enzyme activities were stable at acid pH (3.8), with pH optima of 3.5 to 4.5. Activities were unchanged in the presence of exogenous serine protease inhibitors, divalent cations, and EDTA. We conclude that C. neoformans produces highly active extracellular PLB, LPL, and LPTA under native conditions.

Phospholipase activity in Cryptococcus neoformans: a new virulence factor?

Fifty isolates of Cryptococcus neoformans were examined for extracellular phospholipase production after inoculation onto egg yolk agar; 49 produced a pericolonial precipitate indicative of phospholipase activity. Phospholipase B (PLB), lysophospholipase, and lysophospholipase-transacylase activities were identified by radiometric analysis in supernatants from 4 clinical isolates. The ratio of colony diameter to colony plus precipitate on agar (Pz) correlated with PLB activity. Phospholipase production was similar in 12 environmental and 13 clinical isolates of C. neoformans var. gattii. Environmental strains of C. neoformans var. neoformans (n = 8) produced more phospholipase at 72 h than did 17 clinical isolates (mean Pz, 0.57 vs. 0.72; P < .01); however, Pz values were similar at 96 h. Quantitation of cryptococci in the lungs and brains of BALB/c mice inoculated intravenously with 4 strains expressing high, intermediate, or low phospholipase activity revealed a correlation between phospholipase activity and virulence. Phospholipases secreted by C. neoformans may be implicated in virulence.

Mechanism underlying the effect of pregnenolone sulfate on the kainate-induced current in cultured chick spinal cord neurons

The effect of the neurosteroid pregnenolone sulfate on the kainate receptor-mediated response was studied in cultured chick spinal cord neurons using the whole-cell voltage-clamp recording technique. Pregnenolone sulfate rapidly and reversibly inhibits the kainate-induced current in a dose-dependent manner, with an EC50 of 67 microM and maximal inhibition of 38%. Inhibition by pregnenolone sulfate of the kainate response is not attenuated by increasing concentrations of kainate, suggesting that the blocking action of pregnenolone sulfate is non-competitive. Antagonism of the kainate response by pregnenolone sulfate is neither agonist- nor voltage-dependent, indicating that pregnenolone sulfate does not act as an open-channel blocker. Furthermore, our results demonstrate that pregnenolone sulfate and 1-(4-aminophenyl)-4-methyl-7,8-methylenedioxy-5H-2,3-benzodiazepine (GYKI 52466; a potent non-competitive kainate antagonist) do not act through a common site.

Counseling clinic for pediatric weight reduction: program formulation and follow-up

The feasibility and efficacy of an outpatient-based multicomponent weight reduction program was tested with 68 consecutively enrolled obese children and adolescents. The patients were invited to participate in an individualized six-session program that included parent involvement, diet education, exercise management and behavior modification by a culturally sensitive method. Fifty-six patients were followed up 1 year after treatment. Comparison at pretreatment, end-of-treatment and 1-year-after-treatment with respect to changes in degree of obesity, measured by weight-for-length index (WLI), showed statistically significant differences. Ninety-seven percent of participants were below their pretreatment WLI at the end-of-treatment examination, and 80% at 1-year-after-treatment follow-up. At 1-year-after-treatment, 59% showed a reduction in WLI of 0.1 or more, as compared with 38% of participants at end-of-treatment. Two parameters previously considered predictors of successful weight control, notably age of participants and percentage of weight lost during treatment, were significantly associated with a reduction in the degree of obesity after one year. Although the long-term efficacy cannot be determined, our results indicated that this comprehensive weight reduction program may have an encouraging effect on the weight status of obese Chinese children and adolescents.

Hemopneumothorax missed by auscultation in penetrating chest injury

OBJECTIVE

To determine the frequency and extent of hemothorax, pneumothorax, and hemopneumothorax missed by auscultation in penetrating chest injury.

DESIGN

A retrospective chart and chest radiograph review.

MATERIALS AND METHODS

One hundred and eighteen patients suffering penetrating chest injuries during 1993 were studied. A missed auscultation was defined as a patient with normal breath sounds but shown by chest radiograph to have a hemothorax, pneumothorax, or hemopneumothorax. The amount of hemothorax was recorded after chest tube placement or at thoracotomy. The degree of pneumothorax was determined by Rhea's method.

RESULTS

Seventy-one patients (60%) had a hemothorax, pneumothorax, or hemopneumothorax. Auscultation to detect hemothorax, pneumothorax, or hemopneumothorax had a sensitivity of 58%, a specificity of 98%, and a positive predictive value of 98%. Thirty of 71 patients (42%) were found to have pleural space blood or air missed by auscultation. Twelve patients (41%) had a hemopneumothorax, 11 patients (36%) had hemothorax, and seven patients (23%) had pneumothorax. Auscultation missed hemothorax up to 600 mL, pneumothorax up to 28%, and hemopneumothorax up to 800 mL and 28%.

CONCLUSION

Hemopneumothorax and hemothorax are the conditions most likely to be missed by auscultation, especially in patients with gunshot wounds. Auscultation has a high positive predictive value because it indicates injury with a fair degree of certainty; however, a negative auscultation does not rule out injury.

Inhibition of corticosterone secretion by thyroxine in male rats

The effects of thyroxine (T4) on the secretion of corticosterone both in vivo and in vitro in male rats were studied. Rats were thyroidectomized (Tx) or sham Tx. The Tx rats were subcutaneously with T4 (20 micrograms/kg) or saline once daily for two weeks. In an in vitro experiment, adrenal glands were incubated with ACTH, T4, or ACTH plus T4 in the presence or absence of 0.5 mM 3-isobutyl-1-methylxanthine (IBMX) at 37 degrees C for 60 min. Medium and ether-extracted plasma samples were analyzed for corticosterone by radioimmunoassay (RIA). The accumulation of cyclic adenosine monophosphate (cAMP) in adrenal tissues after incubation with IBMX was measured by RIA. The levels of plasma corticosterone in Tx rats were significantly increased as compared with euthyroid rats. T4 replacement in Tx rats restored plasma corticosterone to euthyroid level. Administration of T4 in vitro resulted in an inhibition of both basal and ACTH-stimulated release of corticosterone. Both basal and ACTH-stimulated generations of cAMP in adrenal tissues were decreased by T4. These results suggest that T4 inhibits the spontaneous and ACTH-stimulated secretion of corticosterone by acting directly at adrenal glands via a decrease in cAMP production.

Clinical utility of color Doppler sonography in the differentiation of hepatocellular carcinoma from metastases and hemangioma

The clinical utility of color Doppler sonography in the differentiation of hepatocellular carcinoma from metastases and hemangioma was investigated in 72 hepatocellular carcinomas (80 lesions), 30 metastases (82 lesions), and 39 hemangiomas (54 lesions). Overlaps of color patterns were found among hepatocellular carcinoma, metastases and hemangioma. Pulsatile waves from lesions with the basket, vessels within tumor, or spot patterns, or lesions measuring less than 3 cm with detectable signals, did not favor the diagnosis of hemangioma. In conclusion, color Doppler sonography can aid in the differentiation of hepatocellular carcinoma from hemangioma but may be unreliable in the differentiation of hepatocellular carcinoma from hypervascular metastases.

Identification and purification of a spinach chloroplast DNA-binding protein that interacts specifically with the plastid psaA-psaB-rps14 promoter region

We have previously shown the presence in chloroplasts of sequence-specific DNA-binding proteins that interact specifically with two regions located downstream and upstream from the 5'-transcription start site of the plastid psaA-psaB-rps14 operon. As part of an effort to elucidate the regulatory mechanism of plastid transcription during plant development, we report here the purification and characterization of the chloroplast DNA-binding protein from spinach (Spinacia oleracea L. var. spinosa Ashers et Graeden) leaves that specifically recognizes sequences between positions +64 to +83 relative to the transcription start site. This DNA-binding protein has been highly purified from chloroplasts by using a combination of high-salt extraction, ammonium sulfate precipitation, heparin-agarose chromatography, and sequence-specific DNA-affinity chromatography. The protein exhibited an apparent molecular weight of 59-60 kDa on the basis of gel filtration. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by Southwestern blot analysis further indicated that this DNA-binding protein is dimeric and composed of two approximately 31-kDa subunits. We discuss the properties of this protein in relation to the known chloroplast DNA-binding factors for plastid gene expression.