Periorbital erythema and swelling as a presenting sign of lupus erythematosus in tertiary referral centers and literature review

Background Cutaneous lupus erythematosus (CLE) includes a broad range of dermatologic manifestations. Periorbital involvement, however, is a relatively rare clinical presentation of CLE. Objectives This clinical study aimed to investigate the characteristics of this unique presentation of CLE in tertiary medical centers. Methods We enrolled patients with periorbital erythema and swelling as the presenting sign of lupus erythematosus, from January 2003 to November 2017, using the data of 553 pathologically proven CLE cases from the registration database of the Chang Gung Memorial Hospitals in Taiwan. Results We enrolled a total of 25 patients. The mean age was 46.7 years and 68% of the patients were female. Most of the patients (84.0%) presented with unilateral involvement, with the left orbit involved in 15 patients (60%); the upper eyelid was the most frequently involved (72%). Mean duration between the onset of clinical manifestations and the diagnosis of CLE was approximately 59 weeks. Nineteen patients had been previously misdiagnosed. All patients had features compatible with CLE on histopathological examination. In contrast, laboratory analysis of the autoimmune profile often revealed negative results, including those for antinuclear antibodies (25%). Notably, anti-SSA/SSB (45.5%) showed the highest positive rate. During follow-up, six patients developed systemic lupus erythematosus (SLE) and two patients developed Sjögren syndrome. Conclusions The diagnosis of CLE presenting as periorbital erythema and swelling is often delayed because of clinical mimicry and the high proportion of negative results on autoantibody tests. Increased clinical suspicion and prompt histopathological examination are crucial for early diagnosis. Moreover, one-fourth of the patients ultimately developed SLE, which highlights the importance of clinical awareness.

Neolysogenization of Xanthomonas campestris pv. citri infected with filamentous phage Cf16

All previously described filamentous bacteriophages are capable of persistent infection while their DNA replicates as an episome in the host cell. Filamentous phage Cf16 undergoes an infectious cycle different from other filamentous phages reported heretofore. Upon initial infection with Cf16, infective centers are formed, each of which produces a large number of phage particles. As the infectious cycle progresses, the phage particles released and infective centers formed per carrier cell decrease with time. Finally, the Cf16 enters a "prophage" state, in which the carrier cell becomes lysogenic containing only one complete phage genome in an integrated form. One out of 10(3)-10(6) lysogenic cells can develop spontaneously into an infective center, which releases only one to two phage particles per cell in stationary phase culture. After infection, the Cf16 genome integrates into the host chromosome and replicates as a part of it. Free RF (replicative form) coexists with the integrated form and replicates independently from host chromosome. Upon further division, carrier cells eliminate the free RF at each succeeding generation. When Cf16 reaches the "prophage" state, only the integrated phage genome remains in the carrier cell with no detectable free RF.

The lysogenic cycle of the filamentous phage Cflt from Xanthomonas campestris pv. citri

A phage, Cflt, forming turbid plaques, was isolated from Xanthomonas campestris pv. citri. After infection, infected sensitive cells become immune to Cflt and produce very few phages. These properties were genetically rather stable. The phage was purified and shown to be filamentous with a size of 1157 +/- 73 nm. The genome size is about 7.62 kb. The phage does not affect the growth of host bacteria. Under natural cultivation conditions Cflt-lysogenized cells could be induced spontaneously to give high phage yields, or cured to give phage-free cells. The integration of Cflt DNA into host DNA was proved by Southern blot hybridization. The lysogenic phage was genetically stable in log phase cells and persisted in stationary phase cells through many cell generations in the absence of extracellular phage reinfection.

Intraductal papillary neoplasia of the liver associated with hepatolithiasis

Intraductal papillary growth of neoplastic biliary epithelia with a fine fibrovascular stalk (intraductal papillary neoplasia of liver [IPN-L]) resembling intraductal papillary mucinous neoplasm of pancreas is occasionally associated with hepatolithiasis. In this study, 136 cases of hepatolithiasis in Taiwan, between January 1998 and March 2000, and an additional 21 cases of IPN-L before December 1998, were examined histologically. IPN-L was found in 41 of 136 hepatolithiasis cases (30.1%). Sixty-two IPN-L cases (42 women and 20 men; age range, 59.8 +/- 10 years) were divided into 4 types (type 1, IPN-L with low-grade dysplasia, 23 cases; type 2, IPN-L with high grade dysplasia, 11 cases; type 3, IPN-L with in situ and microinvasive carcinoma, 13 cases; and type 4, IPN-L of types 2 and 3 with distinct invasive carcinoma, 15 cases). Intraductal spreading and glandular involvement were commonly observed in all types. About half of types 3 and 4 cases had mucobilia, and mucinous carcinoma was variably found in two thirds of group 4 patients. IPN-L frequently showed variable gastroenteric differentiation such as goblet cells and foveolar and colon-like metaplasia. IPN-L with goblet cells and colon-like metaplasia was frequently associated with overproduction of mucin and mucobilia (P <.01). In Japan, IPN-L was not frequent in hepatolithiasis (12 of 135 cases). In conclusion, IPN-L forms a spectrum of biliary neoplasm in hepatolithiasis. It often displays variable gastroenteric metaplasia and significant intraductal spread. IPN-L tends to progress to mucinous carcinoma. Formerly reported "mucin-producing intrahepatic cholangiocarcinoma" with a favorable prognosis is included in IPN-L.

Classification of thymic epithelial neoplasms: a controversial issue coming to an end?

The classification of thymic epithelial neoplasms has been one of the most controversial issues in tumor pathology. There are two opposing schools of pathologists holding different views regarding the classification of thymic epithelial neoplasms. One school of pathologists believe that histological classification of thymomas is not possible or useful. Another school of pathologists believe that thymomas can be histologically subclassified despite their complex histomorphology and that these histological subtypes correlate with their aggressiveness and clinical behavior. A compromised histological classification has been established by World Health Organization (WHO) to designate thymic epithelial neoplasms with letters and numbers. This classification should be adopted internationally to facilitate the communication among concerned pathologists and oncologists. A simple histological classification of thymomas based on cytomorphology and supported by cytokeratin expressions is proposed and compared to the WHO and Müller-Hermelink's histogenetic classifications.

Specificity of the histopathological triad for the diagnosis of toxoplasmic lymphadenitis: polymerase chain reaction study

Toxoplasmosis is a common cause of lymphadenopathy, but toxoplasmic cysts are not usually found in histological sections used for establishing diagnosis, except on extremely rare occasions. The histopathological triad of florid reactive follicular hyperplasia, clusters of epithelioid histiocytes, and focal sinusoidal distention by monocytoid B cells has been considered to be diagnostic of toxoplasmic lymphadenitis, but the validity of the histopathological triad is based indirectly on serological correlation only. The demonstration of Toxoplasma gondii DNA in lymph nodes displaying the histopathological triad will indicate the validity of the histopathological triad as the criterion for the histopathological diagnosis of toxoplasmic lymphadenitis. We used frozen tissues of 12 lymph nodes with the histopathological triad and tissues of 27 lymph nodes from patients with various other conditions (including 13 cases of follicular lymphoid hyperplasia, FLH; three cases of dermatopathic lymphadenopathy, DPL; two cases of plasmacytosis; two cases of Castleman's disease; two cases of metastatic adenocarcinoma; and five cases of lymphoma) to detect T. gondii DNA by polymerase chain reaction. Ten out of 12 lymph nodes with the triad and six out of 27 lymph nodes without the triad were positive for T. gondii DNA. Thus, the sensitivity of the triad was 62.5% (10/16) and the specificity was 91.3% (21/23). The predictive value of positive tests was 83.3% (10/12) and the predictive value of negative tests was 77.7% (21/27). The six cases positive for T. gondii DNA without the triad were four cases of FLH, one case of DPL, and one case of plasmacytosis. None of the neoplastic diseases was positive. The false positive and negative cases could be due to sampling problems or past T. gondii infection. The results confirm that the histopathological triad is highly specific for the diagnosis of toxoplasmic lymphadenitis and can be used confidently.

Induction of a mitosis delay and cell lysis by high-level secretion of mouse alpha-amylase from Saccharomyces cerevisiae

Some foreign proteins are produced in yeast in a cell cycle-dependent manner, but the cause of the cell cycle dependency is unknown. In this study, we found that Saccharomyces cerevisiae cells secreting high levels of mouse alpha-amylase have elongated buds and are delayed in cell cycle completion in mitosis. The delayed cell mitosis suggests that critical events during exit from mitosis might be disturbed. We found that the activities of PP2A (protein phosphatase 2A) and MPF (maturation-promoting factor) were reduced in alpha-amylase-oversecreting cells and that these cells showed a reduced level of assembly checkpoint protein Cdc55, compared to the accumulation in wild-type cells. MPF inactivation is due to inhibitory phosphorylation on Cdc28, as a cdc28 mutant which lacks an inhibitory phosphorylation site on Cdc28 prevents MPF inactivation and prevents the defective bud morphology induced by overproduction of alpha-amylase. Our data also suggest that high levels of alpha-amylase may downregulate PPH22, leading to cell lysis. In conclusion, overproduction of heterologous alpha-amylase in S. cerevisiae results in a negative regulation of PP2A, which causes mitotic delay and leads to cell lysis.

UV-induced increase in RNA polymerase activity in Xanthomonas oryzae pathovar oryzae

UV radiation is thought to inhibit transcriptional elongation, as a result of the formation of pyrimidine dimers in the DNA template, as well as to activate specific transcription factors. However, the effect of UV radiation on the enzymatic activity of RNA polymerase has remained unknown. With the use of an in vitro assay, UV irradiation of Xanthomonas oryzae pathovar oryzae has now been shown to increase RNA polymerase activity. This effect was maximal at a UV dose of approximately 12 J m(-2) and at approximately 60 min after irradiation. It was also not inhibited by pretreatment of cells with chloramphenicol, an inhibitor of protein synthesis. Immunoprecipitation with antibodies to the RNA polymerase core enzyme revealed that exposure of the bacterial cells to UV radiation induced the association of the core enzyme with a protein of approximately 29 kDa. These results demonstrate that UV radiation increases the activity of RNA polymerase, and they suggest that this effect may be related to the repair of DNA damage.

Granulomatous variant of chronic pigmented purpuric dermatosis: report of two cases

Two patients presenting with chronic pigmented purpuric dermatosis (CPPD) on the dorsum of both feet were found to show granulomatous inflammation superimposed on the pathological changes of CPPD. Two similar cases have been reported from Japan. The unique clinicopathological features of this group of patients suggest that they have a rare granulomatous variant of CPPD.

Structural and functional characterization of the lexA gene of Xanthomonas campestris pathovar citri

The role of the LexA protein and, specifically, its effect on recA expression were analyzed in Xanthomonas campestris pathovar citri (X.c. pv. citri). Overexpression of LexA from X.c. pv. citri, in the plant pathogen, as well as in Escherichia coli, results in increased sensitivity to the DNA-damaging agents mitomycin C and ultraviolet radiation, indicating that the recombinant X.c. pv. citri LexA protein is functional in a different bacterial species. Immunoblot analysis revealed that the overexpressed LexA protein functioned as a repressor of recA expression in X.c. pv. citri, and that the mitomycin C-induced increase in the abundance of RecA was accompanied by specific proteolysis of LexA that required RecA. Although the LexA protein from X.c. pv. citri also blocked the expression of recA in E. coli, the E. coli RecA protein was not able to support the autocatalytic cleavage of LexA from the plant pathogen. The transcription start site of the X.c. pv. citri lexA gene was identified, and the region upstream of this gene was shown to confer responsiveness to mitomycin C on a luciferase reporter gene construct. Electrophoretic mobility-shift assays demonstrated that X.c. pv. citri LexA interacts with the promoter region of X.c. pv. citri lexA, as well as with those of the recA genes of X.c. pv. citri and E. coli. These results indicate that LexA functions as a repressor of gene expression in X.c. pv. citri just as it does in E. coli.

Characterization of a Saccharomyces cerevisiae mutant with oversecretion phenotype

An oversecreting mutant of Saccharomyces cerevisiae was obtained from about 400 meiotic segregants derived from thediploid cells made by crossing the HBsAg-induced mutant NI-C with the wild-type strain Sey6211. When transformed with a plasmid containing mouse alpha-amylase cDNA, the mutant (NI-C-D4) exhibited an increased capacity (up to 13-fold) for the secretion of mouse alpha-amylase, higher than the parental strains and other standard wild-type strains. It was also shown that alpha-amylase secreted by the oversecreting mutant had a higher activity and contained more of the non-glycosylated form than the glycosylated form. This isolated oversecreting, low-glycosylation mutant may prove to be a potential S. cerevisiae host for the production of foreign proteins. Further genetic analysis suggested that the mutation responsible for the mutant's oversecretion was partially dominant and that both the oversecretion and low-glycosylation phenotypes were governed by a single chromosome mutation. These pleiotrophic phenotypes may be attributed to a defect in the synthesis of an ER-resident chaperone.

Presence of Epstein-Barr virus latent membrane protein 1 gene in the nasopharyngeal swabs from patients with nasopharyngeal carcinoma

BACKGROUND

Nasopharyngeal carcinoma (NPC) is the most common head and neck malignancy in southeastern China and Taiwan. Early detection of the local disease followed immediately by proper treatment is essential to increase the cure and survival rates. Because every NPC tumor cell carries Epstein-Barr Virus (EBV) genomes, detection of EBV genomic DNA such as latent membrane protein 1 gene (LMP1) might indicate the presence of NPC. We developed a simple and noninvasive technique of nasopharyngeal swabbing to acquire nasopharyngeal cells for detecting the presence of EBV genome. The aim of this study was to investigate the feasibility and reliability of this technique.

METHODS

We collected nasopharyngeal cells by means of a nasopharyngeal swabbing technique and detected the presence of EBV LMP1 with polymerase chain reaction (PCR). Thirty-eight swab specimens were obtained from patients with NPC who were newly diagnosed or were just beginning radiotherapy. Two groups of control subjects were recruited, including 20 patients with other head and neck cancers and eight family members of the NPC patients. An additional group of 65 NPC patients were enrolled in the course of regular follow-up after definitive radiotherapy.

RESULTS

All of the samples yielded sufficient DNA for PCR amplification. Thirty-six of 38 NPC swab samples were positive for EBV LMP1, and all the control subjects had swab sample results negative for EBV. All five patients with suspected local recurrence exhibited positive EBV test results.

CONCLUSIONS

Demonstration of EBV LMP1 in the nasopharyngeal swab specimens detected NPC with a sensitivity of 94.7% and specificity of 100%. This study confirms the reliability and feasibility of nasopharyngeal swab in the predicting and screening of NPC.

Reduction in mitochondrial respiratory capacity in Saccharomyces cerevisiae induced by expression of hepatitis B virus surface antigen

Transformants of Saccharomyces cerevisiae strain TL154 (MATalpha, trp1, leu2) expressing hepatitis B virus surface antigen showed reduced rates of cell growth compared with those of nontransformed cells. The rates of phosphorylative, nonphosphorylative, and uncoupled respiration in mitochondria isolated from the transformants were reduced relative to those of mitochondria derived from nontransformed cells, regardless of whether the cells were cultured in rich or minimal medium. The electrophoretic protein profiles of cell and mitochondrial extracts did not differ substantially between transformed and nontransformed cells. These results suggest that the reduced rate of mitochondrial respiration in the transformants may be due to impairment of metabolic function rather than to inhibition of the expression of components of the respiratory chain.

Pathologic studies of fatal cases in outbreak of hand, foot, and mouth disease, Taiwan

In 1998, an outbreak of enterovirus 71-associated hand, foot, and mouth disease occurred in Taiwan. Pathologic studies of two fatal cases with similar clinical features revealed two different causative agents, emphasizing the need for postmortem examinations and modern pathologic techniques in an outbreak investigation.

Acute encephalomyelitis during an outbreak of enterovirus type 71 infection in Taiwan: report of an autopsy case with pathologic, immunofluorescence, and molecular studies

We report a fatal case of enterovirus type 71 (EV 71) infection in an 8-year-old girl during a summer outbreak of hand, foot, and mouth disease in 1998 in Taiwan. The clinical course was rapidly progressive, with manifestations of hand, foot, and mouth disease, aseptic meningitis, encephalomyelitis, and pulmonary edema. The patient died 24 hours after admission. Postmortem study revealed extensive inflammation in the meninges and central nervous system and marked pulmonary edema with focal hemorrhage. Brain stem and spinal cord were most severely involved. The inflammatory infiltrates consisted largely of neutrophils involving primarily the gray matter with perivascular lymphocytic cuffing, and neuronophagia. The lungs and heart showed no evidence of inflammation. EV 71 was isolated from the fresh brain tissues and identified by immunofluorescence method with type-specific EV 71 monoclonal antibody. It was also confirmed by neutralization test and reverse-transcriptase polymerase chain reaction with sequence analysis. The present case was the first example in which EV 71 was demonstrated to be the causative agent of fatal encephalomyelitis during its epidemic in Taiwan.

Real-time PCR for quantitative detection of Toxoplasma gondii

The protozoan Toxoplasma gondii is one of the most common infectious pathogenic parasites and can cause severe medical complications in infants and immunocompromised individuals. We report here the development of a real-time PCR-based assay for the detection of T. gondii. Oligonucleotide primers and a fluorescence-labeled TaqMan probe were designed to amplify the T. gondii B1 gene. After 40 PCR cycles, the cycle threshold values (C(T)) indicative of the quantity of the target gene were determined. Typically, a C(T) of 25.09 was obtained with DNA from 500 tachyzoites of the T. gondii RH strain. The intra-assay coefficients of variation (CV) were 0.4, 0.16, 0.24, and 0.79% for the four sets of quadruplicate assays, with a mean interassay CV of 0.4%. These values indicate the reproducibility of this assay. Upon optimization of assay conditions, we were able to obtain a standard curve with a linear range (correlation coefficient = 0.9988) across at least 6 logs of DNA concentration. Hence, we were able to quantitatively detect as little as 0.05 T. gondii tachyzoite in an assay. When tested with 30 paraffin-embedded fetal tissue sections, 10 sections (33%) showed a C(T) of <40 and were scored as positive for this test. These results were consistent with those obtained through our nested-PCR control experiments. We have developed a rapid, sensitive, and quantitative real-time PCR for detection of T. gondii. The advantages of this technique for the diagnosis of toxoplasmosis in a clinical laboratory are discussed.

High-frequency interconversion of turbid and clear plaque strains of bacteriophage f1 and associated host cell death

Under normal cultivation conditions, a mixture of turbid and clear plaques is often apparent in cultures of bacterial cells infected with filamentous bacteriophages. Beginning with a culture of wild-type filamentous phage f1, which itself produces turbid plaques, a clear plaque strain (c1) was isolated. From c1, the turbid plaque strain t1 was isolated; from t1, the clear plaque strain c2 was isolated; and from c2, the turbid plaque strain t2 was isolated. Each of these strains was generated with a frequency of approximately 1 x 10(-4). Although filamentous phages have been thought not to induce host cell death, both turbid and clear plaque strains of f1 killed host bacteria. Plating of bacterial cells 1 h after infection revealed that colonies produced by cells infected with either wild-type f1 or strain c2 were smaller than those derived from uninfected cells, and that colony formation by infected cells was reduced by 15% and 38%, respectively. The time course of bacterial growth revealed that, at 4 h after infection, the number of CFU per milliliter of culture of cells infected with wild-type f1 or with strain c2 was reduced by 27% and 95%, respectively, compared with that for uninfected cells. Microculture analysis also revealed that the percentages of nondividing cells in f1 or c2 infected were 19% and 52%, respectively, 4 h after infection with wild-type f1 or with strain c2; no such cells were detected in cultures of uninfected cells. Negative staining and electron microscopy showed that 20% and 61% of cells infected with wild-type f1 or with strain c2 were dead 4 h postinfection. Finally, although the rates of DNA synthesis were similar for infected and uninfected cells, the rates of RNA and protein synthesis were markedly reduced in infected cells.

Frequent presence of neuroendocrine small cells in thymic carcinoma: a light microscopic and immunohistochemical study

AIMS

Neuroendocrine differentiation has been described in conventional carcinomas of various organs. Small cells postulated to be neuroendocrine cells were observed previously in some thymic carcinomas. This study was conducted to confirm and characterize the presence of neuroendocrine small cells in thymic carcinomas by light microscopy and immunohistochemistry.

METHODS AND RESULTS

Twenty-two thymic carcinomas were studied by light microscopy to detect the presence of small neuroendocrine-like cells. They were found in four of 10 squamous cell carcinomas (SCC) and seven of eight adenosquamous carcinomas (ASC). No small cells were observed in three lymphoepithelioma-like carcinomas (LELC) and one adenocarcinoma. The small cells were located within the tumour nests and constituted less than 1% of the entire tumour. In one case, small cells also extended outside the tumour nests. Rosette formation was seen in three cases. They were proved to be neuroendocrine cells by their immunoreactivity to neuron-specific enolase, chromogranin A, and/or synaptophysin. A few scattered neuroendocrine small cells were found only by immunohistochemistry in one case each of SCC, ASC, and LELC. The small cells were also strongly positive for cytokeratin (CK) 8 and CK18 but negative for CK19 and CK20. The predominant carcinoma cells other than the neuroendocrine small cells also displayed neuroendocrine markers in 68% of the cases studied.

CONCLUSIONS

Neuroendocrine small cells can be recognized by light microscopic examination in approximately 61% of thymic SCC and ASC. Neuroendocrine markers, CK8 and CK18 can aid in confirming their presence. The neuroendocrine small cells present in thymic carcinomas are different from the main carcinoma cells displaying immunohistochemical neuroendocrine markers. The presence of neuroendocrine small cells could be an useful marker for the differentiation of thymic carcinomas from thymomas and carcinomas of other sites.

p16INK4 gene mutation and allelic loss of chromosome 9p21-22 in Taiwanese hepatocellular carcinoma

BACKGROUND

The p16INK4 (MTS1/CDNK2A) gene, located on chromosome 9p21, is an inhibitor of cyclin-dependent kinase 4. Various data have shown that it is frequently inactivated in several types of cell lines and primary human cancers.

MATERIALS AND METHODS

Thirty cases with hepatocellular carcinoma were studied for possible p16INK4 gene mutation in Taiwan. Homozygous deletion was determined using polymerase chain reaction (PCR). The p16INK4 gene mutation was first screened by single strand conformation polymorphism, then direct DNA sequencing was performed on the cases with mobility shifts. Deletion mapping of chromosome 9p21-22 was also carried out with two polymorphic microsatellite markers (D9S925 and D9S168) using PCR.

RESULTS

One of the 30 cases had homozygous deletion at exon 3 of the p16INK4 gene. Another tumor had altered electrophoresed mobility in exon 2 with G to T transversion in the first nucleotide of codon 61 by direct sequencing causing a stop codon (GAG-->TAG). At the D9S925 and D9S168 loci, six out of 24 (25%) and three out of 19 (16%) informative cases showed loss of heterozygosity, respectively.

CONCLUSION

Point mutation and homozygous deletion of the p16INK4 gene are present in a subset of hepatocellular carcinomas in Taiwan. The patterns of the p16INK4 gene alteration are, however, different from those from other regions. In addition, allelic loss on chromosome 9p21-22 is not an uncommon event in hepatocellular carcinomas. Therefore, the significance of chromosome 9p loss deserves to be extensively investigated.

Generalized granuloma annulare associated with granulomatous mycosis fungoides

We describe a 68-year-old man with plaque stage mycosis fungoides (MF) for 8 years. He developed tumorous lesions of granulomatous MF (GrMF) and generalized granuloma annulare (GA) after a previously indolent clinical course. Since then, the clinical course was aggressive with involvement of the bone marrow and lymph nodes, and leukemic change occurred. Systemic chemotherapy was given, but the patient died 9 months later due to neutropenic fever and septic shock. GA in malignant lymphoma has been reported most frequently in association with Hodgkin's disease. To the best of our knowledge, GA associated with GrMF has never been reported in the English language literature. The prognostic significance of the association of granulomatous inflammation and malignancy is reviewed.

Asparagine as a nitrogen source for improving the secretion of mouse alpha-amylase in Saccharomyces cerevisiae protease A-deficient strains

A modified chemically defined medium was achieved by using asparagine as a nitrogen source to increase the production of secreted mouse alpha-amylase in several Saccharomyces cerevisiae protease A-deficient (pep4) strains. The specific productivity (quantity) and the 53 kDa non-glycosylated active form (quality) of mouse salivary alpha-amylase in liquid medium containing asparagine was remarkably improved compared to media containing other nitrogen sources, including ammonium sulphate, glutamic acid, arginine, casamino acids, yeast extract and peptone. Similar improvement was also observed on starch solid agar regarding the clarity and size of the halo zone formed by alpha-amylase activity. Compared with ammonium sulphate, advantages of using asparagine as the nitrogen source in liquid or solid medium included increasing the cell mass of test strains, recovering the viability of protease-deficient strains to levels similar to the wild-type strain, and increasing the copy number of the mouse alpha-amylase expression vector in test strains. In turn, these advantages apparently contributed to the increase of secretion of mouse alpha-amylase in several test strains and especially in the protease A-deficient strains. In addition to demonstrating the use of modified chemically defined medium to improve the quality and quantity of secreted mouse alpha-amylase, this study also provides a new strategy to improve the secretion of heterologous proteins in protease A deficient strains.

Requirement for phosphoglucose isomerase of Xanthomonas campestris in pathogenesis of citrus canker

A mutant (XT906) of Xanthomonas campestris pv. citri, the causal agent of citrus canker, was induced by insertion of the transposon Tn5tac1 and isolated. This mutant did not grow or elicit canker disease in citrus leaves but was still able to induce a hypersensitive response in a nonhost plant (the common bean). The mutant was also unable to grow on minimal medium containing fructose or glycerol as the sole carbon source. A 2.5-kb fragment of wild-type DNA that complemented the mutant phenotype of XT906 was isolated. Sequence analysis revealed that this DNA fragment encoded a protein of 562 amino acids that shows homology to phosphoglucose isomerase (PGI). Enzyme activity assay confirmed that the encoded protein possesses PGI activity. Analysis of the activity of the promoter of the pgi gene revealed that it was inhibited by growth in complex medium but induced by culture in plant extract. These results demonstrate that PGI is required for pathogenicity of X. campestris pv. citri.

The pilA gene of Xanthomonas campestris pv. citri is required for infection by the filamentous phage cf

Host factors that are important for infection of Xanthomonas campestris pv. citri by the filamentous bacteriophage cf were investigated by transposon mutagenesis with Tn5tac1. A mutant, XT501, that was resistant to cf infection was recovered, showing that the gene inactivated by the transposon is required for infection by the phage but not for cf replication or assembly. A 1.7-kb SacI-ApaI DNA fragment from XT501 containing the bacterial DNA flanking one end of the transposon was cloned and shown to be required for cf infection. Nucleotide sequence analysis of the 1.7-kb fragment reveals the presence of an ORF that encodes a protein of 146 amino acids. This protein shows 42% identity to the type 4 prepilin encoded by the pilA genes of other bacteria. The pilA gene of X. campestris pv. citri is thus essential for infection by the bacteriophage cf.

The primary immunity determinant in modulating the lysogenic immunity of the filamentous bacteriophage cf

Bacteriophage cf is the first single-stranded DNA phage that has been shown to set up a stable lysogenic state with its genome integrated into the host chromosome. From the isolation and characterization of a virulent mutant, cf-tv2, we report the first investigation into the mechanisms of the immunity established by the filamentous bacteriophage. The mutation in cf-tv2 enables the phage to produce plaques on lawns of cf lysogenic cells. The mutation was defined as a 49-nucleotide deletion located in a 0.59 kb NcoI/KpnI fragment of cf replicative form DNA. Two messages, cM1 and cM2, transcribed from the immunity region of wild-type cf but in opposite directions, were detected. In cf-tv2, the 49-nucleotide deletion abolishes cM2 transcription. The primer extension assay suggests a possible RNA-RNA interaction directed by base-pairing of the cM1 and cM2 RNAs. A frameshift mutation of the open reading frame ORF 165, encoded by cM2, resulted in a 10(5) plating efficiency on the cf lysogen. These observations suggest that both RNA-RNA interaction and repressor protein inhibition are involved in the mechanism of cf immunity. A model is proposed for the regulation of cf immunity.

Transcription of the genome of the filamentous bacteriophage cf from both plus and minus DNA strands

The filamentous bacteriophage cf infects the bacterium Xanthomonas campestris pv. citri. Northern blot analysis with probes derived from various restriction fragments of cf replicative form (RF) DNA has revealed the presence of five major phage-specific transcripts in infected cells. Four of these transcripts were shown to be derived from the region of the cf genome extending from gene II to gene VIII and are consistent with the cascade model of transcription proposed for Ff coliphages. These transcripts overlap with each other and terminate upstream of an efficient Rho-independent transcription terminator. Unlike the well-characterized Ff phages, in which only the minus strand of viral DNA serves as a transcription template, both strands of the RF DNA of phage cf appeared to be transcribed. Thus one of the five major cf transcripts was shown to be derived from a region of the viral minus strand that contains an open reading frame encoding a putative polypeptide of 165 amino acids. Primer extension analysis mapped the transcriptional initiation site of this RNA to a cytosine residue at position 870. A partial transcription map of phage cf revealed two independent regions of transcriptional activity. The region with the highest activity coincides with that encoding the polypeptides required in the largest amounts during the cf infection cycle.

A variant of Saccharomyces cerevisiae pep4 strain with improved oligotrophic proliferation, cell survival and heterologous secretion of alpha-amylase

A variant of Saccharomyces cerevisiae pep4 strain 20B12, with improved oligotrophic proliferation, cell survival and secretion of heterologous mouse alpha-amylase, is described. Previously we reported a procedure to enrich NI transformants that are not inhibited by cytotoxic expression of hepatitis B virus surface antigen in the secretion pathway of the protease-A-deficient (pep4) strain. To use the NI cells as a host for heterologous expression, we tried to amend the introduced pYAS/12S vector and obtain a host strain, NI-C, with stable NI phenotype and trp1 marker restored. Southern analysis of genomic DNA of NI-C suggested that the original pYAS/12S was abnormally rearranged and not completely corrected. Further assay showed that the viability and mitotic ability of the NI-C strain were increased. While using the NI-C strain as host for plasmid transformation and heterologous expression of mouse alpha-amylase, we observed that transformed colonies grew more quickly and secreted more alpha-amylase than general yeast strains. A further test showed that the NI-C strain was able to use mouse alpha-amylase as a positive selection marker to form transformed colonies on nitrogen-starved plates that contain starch as the sole carbon source. The results imply that the NI-C variant is an improved pep4 strain that can be used for heterologous expression and for the development of new selective markers in the yeast transformation system.

Subcutaneous panniculitic T-cell lymphoma developing in a child with idiopathic myelofibrosis

PURPOSE

Subcutaneous panniculitic T-cell lymphoma is reported in a child with idiopathic myelofibrosis. Both disease entities are rarely seen in children.

PATIENT AND METHODS

A girl aged 5 years and 9 months had pancytopenia and severe constitutional symptoms. Idiopathic myelofibrosis was subsequently diagnosed.

RESULTS

A transient response was achieved after treatment with a course of high-dose methylprednisolone therapy. However, proptosis and skin nodules developed during tapering of steroid therapy. A computed tomography scan of the orbit also revealed a mass lesion in the right lacrimal gland region. A skin biopsy specimen showed a subcutaneous panniculitic T-cell lymphoma. The clinical course was marked by high fever, profound pancytopenia, massive gastrointestinal bleeding, and severe, recurrent infections. Her condition rapidly deteriorated, and she died from polymicrobial sepsis 4 months after her initial examination.

CONCLUSIONS

Subcutaneous panniculitic T-cell lymphoma is a distinctive clinicopathologic entity that is rarely seen in children. The association of myelofibrosis and peripheral T-cell lymphoma as seen in this has been rarely reported.

Congenital malignant rhabdoid tumor presenting as a cutaneous nodule: report of 2 cases with review of the literature

OBJECTIVE

The congenital occurrence of malignant rhabdoid tumor (MRT) is rare. Initial presentation of congenital MRT as a skin tumor is even more rare. We report 2 cases in which a cutaneous nodule appeared prior to the discovery of the primary tumor.

METHODS

Histologic, ultrastructural, and immunohistochemical studies were performed on skin nodules from 2 neonates. Other congenital examples of MRT in the literature were reviewed.

RESULTS

Both neonates were male and both were fullterm. Skin nodules were noted at birth. The tumors were located on the right neck in case 1 and on the right back in case 2. The primary tumors were later found in the kidney and the right chest wall, respectively. The skin biopsy of the first case had been interpreted as undifferentiated sarcoma, and MRT was diagnosed after the renal tumor was examined. In the second case, a correct diagnosis was promptly made based on the skin biopsy owing to experience with the first case.

CONCLUSIONS

Congenital MRT is very uncommon and may present as a skin tumor at birth. Since MRT exhibits various histologic patterns, the diagnosis should be made by a complete pathologic study with proper clinical correlation. To our knowledge, the unique mode of manifestation in these 2 cases is described for the first time. We suggest that MRT should be considered when making the differential diagnosis in such a clinical setting.

Thymic carcinoma arising in thymoma is associated with alterations in immunohistochemical profile

Thymic carcinoma is an uncommon tumor. Most cases appear to arise de novo, but in rare instances they can arise in thymomas. We report the clinicopathologic features and immunohistochemical profile of five cases of thymic carcinoma accompanied by a component of thymoma. Immunohistochemical studies were performed with the avidin-biotin-peroxidase complex method using monoclonal antibodies to p53(DO7), CD99(O13), epithelial membrane antigen, CD5(NCL-CD5-4C7), vimentin (V9), and cytokeratins 7, 8, 18, and 19. The patients consisted of three men and two women with a median age of 57 years. One patient had myasthenia gravis, and the other four presented with chest symptoms. One patient had concurrent adenocarcinoma of the lung with metastasis. Four of the patients died within 15 months. The thymomas consisted of two large polygonal cell thymomas, two squamoid thymomas, and one spindle cell thymoma. The malignant components included two undifferentiated carcinomas, one spindle cell carcinoma, one squamous cell carcinoma, and one clear cell carcinoma with squamous differentiation. There was no correlation between the histologic types of the thymoma and the thymic carcinoma. In three cases, excluding the two squamoid thymomas, the thymic carcinomas occurred in the necrotic areas of the thymoma. They showed upregulated expression of epithelial membrane antigen and cytokeratins 7, 8, 18, and 19, similar to the so-called "interface phenomenon" described in the invasion front of other types of carcinoma. Increased p53 protein expression was observed in all five carcinomas, and there was loss of CD99+ immature T lymphocytes. Among the thymic carcinomas, only the squamous component of the clear-cell carcinoma stained for CD5, a marker commonly expressed in thymic carcinomas. Paradoxically, a squamoid thymoma, but not its associated spindle cell carcinoma, expressed CD5, suggesting the acquisition of an "aggressive" phenotype by the squamoid thymoma, but with loss of the marker on malignant transformation. One undifferentiated carcinoma acquired vimentin immunoreactivity, whereas four other carcinomas and all five thymomas were negative. In conclusion, thymic carcinoma can arise in any histologic type of thymoma, including spindle cell thymoma, which is generally regarded as a benign neoplasm. The prognosis appears to be poor. Tumor necrosis in a thymoma should alert the pathologist to search for malignant change. The malignant change is commonly associated with increased expression of epithelial membrane antigen, cytokeratin subtypes, or p53 protein, and loss of CD99+ immature T lymphocytes, and is occasionally associated with a change in the expression of CD5 or vimentin.

Disassociation of sigma subunit from RNA polymerase of Xanthomonas oryzae pv. oryzae by phage Xp10 infection

The sigma subunit of Xanthomonas oryzae pv. oryzae is disassociated from host RNA polymerase after phage Xp10 infection. To clarify the possible mechanism for this observation, sigma subunit was purified and an antiserum against sigma subunit was prepared. Immunoprecipitation of RNA polymerase by the anti-core RNA polymerase antiserum, followed by immunoblotting with anti-sigma subunit antibody, revealed that sigma subunit was lost from RNA polymerase within 10 minutes after Xp10 infection. Loss of sigma subunit was not observed under other stress conditions including heat and cold stress, starvation and growth to stationary phase. Two-dimensional immunoblotting analysis did not reveal any covalent modification of either sigma subunit or RNA polymerase after Xp10 infection. These results suggest that separation of th subunit from RNA polymerase may be due to competition with other binding factors.

Keloidal dermatofibroma: report of 10 cases of a new variant

Dermatofibroma is a common cutaneous tumor. Unusual variants of dermatofibroma that exhibit various epidermal changes or different cellular composition have been described. We observed 10 cases of a novel variant of dermatofibroma characterized by keloidal change within the tumor. Formalin-fixed, paraffin-embedded tissues were used for histochemical and immunohistochemical studies. The patients consisted of six women and four men; median age was 34 years (17 to 59 years). All tumors occurred on the extremities, and six were present for at least 2 years. Tenderness was mentioned in four cases. They were described as erythematous or brown papules 1 cm or smaller. Clinical appearance did not deviate from that of ordinary dermatofibromas. Microscopically, the excised tumors showed a superficial circumscribed area of keloidal change under an atrophic epidermis in an otherwise ordinary dermatofibroma. In the keloidlike area, multinucleated giant cells, hemorrhage, hemosiderin deposits, and scattered KiM1P-positive histiocytes, but not factor XIIIa-positive or CD34-positive cells were present among the thick collagen fibers. There were no known recurrences. This variant dermatofibroma should not be overlooked as a simple keloidal scar. The observation of keloidal change in dermatofibromas may support the connotation that trauma is a possible cause of dermatofibroma. The fact that Asian people are more prone to develop keloid may have led us to find this new variant.

Granulocytic sarcoma presenting as a giant breast tumor in a pregnant woman: a case report

We report a case of granulocytic sarcoma (chloroma) presenting as a giant breast tumor in a pregnant woman with no history of leukemia. The case was initially diagnosed as medullary carcinoma on a biopsy specimen and a modified radical mastectomy was performed. The diagnosis of granulocytic sarcoma requires the pathologist's high index of suspicion. The presence of immature eosinophils was an important clue. Leder's chloroacetate esterase stain; immunostaining for myeloperoxidase, CD34, CD43, CD68, and lysozyme; and ultrastructural finding of cytoplasmic lysosomal granules and Auer bodies all aided in confirming the diagnosis. It is imperative to recognize granulocytic sarcoma to avoid unnecessary surgery. Granulocytic sarcoma should be included in the differential diagnosis of breast tumors, especially in tumors with diffuse proliferation of small tumor cells.

Leukemia cutis as the initial manifestation of acute nonlymphocytic leukemia in a young child

A 15-month-old boy was well except for asymptomatic, erythematous, wheal-like papuloplaques, macules, and nodules on his face and four extremities. It was misdiagnosed by a pediatrician and treated as urticaria for six months. Later, he was sent to our hospital for evaluation of prolonged fever. Acute nonlymphocytic leukemia (M5) with leukemia cutis was diagnosed by results of hematologic examination and examination of a skin biopsy specimen. After one course of chemotherapy, all of the skin lesions completely resolved and had not recurred. Five months after acute nonlymphocytic leukemia was diagnosed, bone marrow relapse and central nervous system involvement were noted.

Cutaneous involvement in polyvinylpyrrolidone storage disease: a clinicopathologic study of five patients, including two patients with severe anemia

Polyvinylpyrrolidone (PVP), formerly a plasma expander, has continued to be inappropriately used in Taiwan for intravenous injection as a "blood tonic." Five cases of PVP storage disease with cutaneous involvement were studied. Two patients presented with cutaneous eruptions mimicking collagen vascular disease and chronic pigmented purpuric dermatosis. Two other cases were found incidentally: one was with a metastatic tumor and the other in a pemphigus lesion. The fifth case was seen in a blind skin biopsy specimen taken to exclude Niemann-Pick disease after hematologic examination of a bone marrow smear. The latter patient and the patient with a collagen vascularlike disease also had severe anemia and serious orthopedic and neurologic complications due to massive infiltration of PVP-containing cells in the bone marrow with destruction of the bone. Severe irreversible anemia due to PVP storage disease has not been reported before. Three patients admitted having a history of receiving intravenous injection of PVP. The samples obtained from two of them indeed contained 5% PVP as determined by chemical analysis. PVP storage disease can be diagnosed by its histopathologic features. The skin biopsy specimens all showed a variable number of characteristic blue-gray vacuolated cells around blood vessels and adnexal structures with positive tinctorial reactions to mucicarmine, colloidal iron, and alkaline Congo red and negative to periodic acid-Schiff (PAS) and alcian blue. The PVP storage cells were shown to be CD68+ macrophages. The presence of PVP in the skin induced little or no inflammatory reaction. Only the pelvic mass in one patient had a foreign body granuloma formation. Our study showed that systemic parenteral administration of PVP preparation could result in the accumulation of PVP storage cells in the skin, with or without clinical eruptions. The diagnosis of systemic PVP storage disease can be established by performing a skin biopsy for pathologic study. It is important for pathologists and clinicians to be aware of this iatrogenic storage disease to avoid misdiagnosis for hereditary storage disease, osteomyelitis, or signet-ring cell carcinoma. Serious hematologic and orthopedic complications can be caused by repeated massive intravenous injection of PVP. Therefore, PVP preparations should be strictly prohibited for systemic administration.

Simultaneous occurrence of papulonecrotic tuberculide and erythema induratum and the identification of Mycobacterium tuberculosis DNA by polymerase chain reaction

The simultaneous occurrence of two tuberculides in one patient is rare. We report the case of a 32-year-old man presenting with both papulonecrotic tuberculide and erythema induratum. Mycobacterial DNA was identified from both skin lesions by polymerase chain reaction using formalin-fixed and paraffin-embedded tissues, suggesting that tuberculides are related to tuberculosis. New skin lesions developed after the patient discontinued his medication on his own initiative, 2 months after triple antituberculous therapy had been started. It is important to continue therapy for a prolonged period.

p53 expression and proliferative activity in Bowen's disease with or without chronic arsenic exposure

A comparative study of Bowen's disease (BD) with or without chronic arsenic exposure may contribute to understanding arsenic carcinogenesis. We compared the p53 overexpression and proliferative activity of 26 cases of BD with chronic arsenic exposure (group I) and 22 comparable cases of BD without chronic arsenic exposure (group II) by immunohistochemical method on formalin-fixed, paraffin-embedded tissues with antibodies PAb1801 and MIB-1, respectively. We also included in this study two squamous cell carcinomas that developed from BD in group I and one in group II. Two paired BD lesions in the same individual of one patient in group I and of three patients in group II were also studied. The significant p53(+) (>10% stained cells) rates were 42.3% (11 of 26) and 9.1% (2 of 22) for groups I and II, respectively, and the difference was statistically significant (P = .01). The p53 expression in different lesions of the same individual remained consistently the same. Squamous cell carcinomas that developed in 2 cases of p53(+) BD in group I were also positive, but the one in 1 case of p53(-) BD in group II was negative. No significant statistical difference in proliferative activity was found between group I BD and group II BD (P= .769), nor between p53(+) cases (>10% stained cells) and p53(-) cases (<10% stained cells) in group I BD (P = .519). This study showed that significant overexpression of p53 protein was higher in BD with chronic arsenic exposure. Therefore, arsenic carcinogenesis of BD might be different from that of BD unrelated to arsenic, and alteration of p53 plays a more important role in the pathogenesis of BD with chronic arsenic exposure. Overexpression of p53 was not a prerequisite for developing squamous cell carcinoma and was not affected by proliferative activity.

Novel and frequent mutations of hepatitis B virus coincide with a major histocompatibility complex class I-restricted T-cell epitope of the surface antigen

We examined the full-length hepatitis B virus (HBV) envelope (surface antigen or HBV small surface antigen [HBsAg]) sequences of 12 different liver samples from 10 different hepatoma-containing chronic carriers. Surprisingly, novel and frequent mutations occurred predominantly at amino acids 40 and 47 of HBsAg, in addition to within a known protective B-cell epitope (so-called group a determinant of HBsAg 124-148). Approximately 58% of chronic carriers contain mutations at the group a determinant. The mutation frequency at the hotspot codons 40 and 47 is approximately 83%, 1 order of magnitude higher than at the known polymorphic sites of subtype-specific determinants at codons 122 and 160, which is approximately 4%. This new mutational domain is found to coincide with a major histocompatibility complex class I-restricted T-cell epitope. The potential biological significance of this novel mutation in the immunopathogenesis of HBV chronic carriers is discussed.

Primary chondrosarcoma of the heart: a case report

Chondrosarcoma involving the heart has been previously reported but is extremely rare. Most chondrosarcoma described in the literature are secondary, and the primary site can be identified. We present an unusual case of primary cardiac chondrosarcoma which originated in the left atrium. Severe pulmonary edema was the first presentation. The sarcoma subsequently metastasized to the mandible and finally recurred in the right heart causing severe pulmonary emboli and myocardial failure.

Single-stranded DNA binding protein from bacteriophage cf: characterization, gene localization and protein-ssDNA complex

The single-stranded DNA binding protein from the filamentous bacteriophage cf has been purified and characterized. The first 12 amino acids, resulting from the N-terminal amino acid sequencing analysis of the protein, agree with an open reading frame (ORF) on the cf genome. The ORF contains 294 bp and codes for a 98 a.a. protein of molecular weight 10.8 kDa, consistent with the result from the denaturing protein gel analysis. The protein appears to be a homodimer as evident from the apparent molecular weight of about 22 kDa obtained from native protein gel analysis. The gene location of the protein has been identified as gene V of the cf single stranded genome, same as that from the M13 phage. The GVP of cf shows a strong sequence homology to the ssDNA binding proteins of Ff, IKe and Pf3 filamentous phages. The DNA binding wing of GVP, conserved among the filamentous phages, has been predicted for cf. To further characterize the protein, the GVP-ssDNA complex of cf has been purified from the infected host (Xanthomonas campestris pv. citri) by density gradient centrifugation. Transmission electron microscopy (TEM) images of the complex showed that it is about 1200 nm in length and 9 nm in diameter and it has a highly regular morphology with a central groove shadow running along the entire structure, but without any apparent helical pattern seen in the M13 complex. The GVP-ssDNA complex of cf seems more rigid than that of M13. Our computer modeling study suggested that this difference between the two complexes may be due to the additional 11 or 12 amino acids at the C-terminal end of the cf-GVP.

Rifampicin: an inhibitor of Xp12-specific protein phosphorylation in Xanthomonas oryzae pv. oryzae

Phosphorylation of the three Xp12-specific phosphoproteins was drastically reduced by rifampicin, an antibiotic that specifically inhibits the host-cell RNA polymerase. However, this inhibitory effect could not be found in spontaneous mutants of Xanthomonas oryzae pv. oryzae whose RNA polymerase are resistant to the drug. The inhibitory effect of rifampicin treatment also resulted suppression of the Xp12 multiplication cycle. This implies the physiological significance of this effect and supports our previous prediction that phosphorylation plays an important role in the life cycle of Xp12. The acid- and alkali-labile character of the Xp12-specific phosphoproteins and the chemical stability of the phosphoryl linkages show that the corresponding protein kinase catalyzes the formation of an acyl phosphorylation. Subsequent fractionation of cell lysate revealed that the phosphoproteins were located in the periplasm. Actinomycin D, which affects transcription through DNA condensation rather than its binding to RNA polymerase, was not able to cause the inhibition effect. On the other hand, cerulenin was found to reduce the acyl phosphorylation which hints at a possible role of cell membrane in the phosphorylation. Here we present the evidence for the functional involvement of the rifampicin treatment on protein phosphorylation. A possible mechanism of rifampicin on the alternation of acyl phosphorylation is proposed.

Acquired generalized hypohidrosis/anhidrosis with subclinical Sjögren's syndrome: report of a case with diffuse syringolymphoid hyperplasia and lymphocytic sialadenitis

The pathogenesis and the underlying pathologic changes of acquired generalized hypohidrosis/anhidrosis (AGHA) are largely unknown. We studied a case of AGHA in a young woman suffering from heat intolerance and progressive loss of sweating. Pathologic study of affected skin revealed unique syringolymphoid hyperplasia with T cell infiltration, suggesting a T cell-mediated autoimmune disease. The patient also had subclinical Sjögren's syndrome and diffuse hair loss. The pathogenesis of the latter two conditions is believed to be related to the patient's AGHA.

Embryonal rhabdomyosarcoma of the uterine corpus mistaken for small cell carcinoma: a case report

Pure rhabdomyosarcomas of the female genital tract mostly occur in infancy and childhood, in the form of sarcoma botryoides (a variant of embryonal rhabdomyosarcoma), with vagina and cervix as typically involved sites. Such tumors rarely occur in the uterine corpus and cervix of adults. We would like to report a pure embryonal rhab-domyosarcoma of the uterine corpus that arose in a 31-year-old, gravida 1, para 1, female patient with widespread bony metastasis, and which was originally mistaken for metastatic small cell carcinoma to bone marrow.

Rapid inhibition of protein histidine phosphorylation by UV-irradiation in Xanthomonas oryzae pv. oryzae

Exposure of Xanthomonas oryzae pv. oryzae cells to 254 nm UV radiation resulted in an alteration of protein phosphorylation. Labelling of the phosphohistidine-containing proteins with molecular masses of 81 and 32 kDa, named p81 and p32, was rapidly reduced following UV irradiation in the early exponential cells, but the decrease was not detected in mid-exponential cells. Mitomycin C, a DNA replication inhibitor, and rifampicin, a drug generally used to inhibit RNA synthesis and DNA replication, were also found to reduce the histidyl phosphorylation. However, this alteration of protein phosphorylation was not hindered by chloramphenicol treatment. A possible role for these histidyl phosphoproteins in sensing UV light is proposed.