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ABSTRACTTalaromyces (Penicillium) marneffeiis an emerging opportunistic pathogen associated with HIV infection, particularly in Southeast Asia and southern China. The rapid uptake and killing of T. marneffeiconidia by phagocytic cells along with the effective induction of an inflammatory response by the host is essential for disease control. T. marneffeiproduces a number of different laccases linked to fungal virulence. To understand the role of the various laccases in T. marneffei, laccase-encoding genes were investigated. Targeted single, double and triple gene deletions of laccases encoding lacA, lacB, and lacCshowed no significant phenotypic effects suggesting redundancy of function. When a fourth laccase-encoding gene, pbrB, was deleted in the ΔlacAΔlacBΔlacCbackground, the quadruple mutant displayed delayed conidiation and the conidia were more sensitive to H2O2, sodium dodecyl sulfate (SDS), and antifungal agents than wild-type and other transformants. Conidia of the quadruple mutant showed marked differences in their interaction with the human monocyte cell line, THP-1 such that phagocytosis was significantly higher when compared with the wild-type at one and 2 hours of incubation while the phagocytic index was significantly different from 15 to 120 minutes. In addition, killing of the quadruple mutant by THP-1 cells was more efficient at 2 and 4 hours of incubation. The levels of the proinflammatory cytokines TNF-α, IL-1β and IL-6 from THP-1 cells infected with the quadruple mutant were also significantly increased in comparison with wild-type. The results demonstrate that production of laccases by T. marneffeiactually promotes the pathogen's resistance to innate host defenses.

ABSTRACTAn emerging pathogenic dimorphic fungus, Penicillium marneffei, is one of the major causes of morbidity in patients with human immunodeficiency virus infection in Southeast Asia. A PCR-hybridization assay has been developed to identify this pathogen. This study describes the use of single and nested PCR methods for the rapid identification of P. marneffei.Two sets of oligonucleotide primers were derived from the sequence of 18S rRNA genes of P. marneffei.The outer primers (RRF1 and RRH1) were fungus specific. The inner primers (Pm1 and Pm2) were specific for P. marneffeiand were used in nested or single PCR. The specific fragment of approximately 400-bp was amplified from both mold and yeast forms of 13 P. marneffeihuman isolates, 12 bamboo rat isolates, and 1 soil isolate, but not from other fungi, bacteria, and human DNA. The amplified products were analyzed by agarose gel electrophoresis followed by ethidium bromide staining. The sensitivities of the single PCR and nested PCR were 1.0 pg/µl and 1.8 fg/µl, respectively. The assay is useful for rapid identification of P. marneffeicultures. Very young culture of P. marneffei(2-day-old filamentous colony, 2 mm in diameter) could be performed by this assay. The species was identified within 7 h (single PCR) or 10 h (nested PCR), compared to 4 to 7 days for confirmation of dimorphism. The application of these PCR methods for early diagnosis of the disease needs to be studied further.

The incidence of Penicillium marneffeiinfection has increased substantially, especially in persons with HIV infection. Very little is known about the natural reservoirs or animal hosts of P. marneffei. This pathogenic fungus was first isolated from a species of bamboo rat (Rhizomys sinensis) in Vietnam and later from another rodent species, R. pruinosus. We studied a total of 75 captured bamboo rats; P. marneffeicould be isolated from the internal organs of 13 of 14 (92··8%) of large bamboo rats, R. sumatrensis, and of 3 of 10 reddish-brown small bay bamboo rats, Cannomys badius(30%). All 51 greyish-black C. badiuswere negative on culture. Among R. sumatrensis, P. marneffeiwere frequently recovered from the lungs (85··7%), spleen (50%) and liver (28··6%). Of the 28 soil samples collected from the bamboo rat burrows and the 67 from the residential areas of patients with P. marneffeiinfection, P. marneffeiwas isolated from one soil sample collected from a burrow of R. sumatrensis. The mycological characteristics of P. marneffeiisolates from bamboo rats and humans were very similar. Our data indicate that R. sumatrensisand C. badiusmay be important animal hosts of P. marneffeiin northern Thailand.

A gene encoding heat shock protein 70 (Hsp70) of Penicillium marneffei was isolated and characterized. The structure of P. marneffei hsp70 gene was similar to hsp70 genes of other organisms, with a unique sequence of 3-nt microexon flanked by two introns. Comparison of the deduced amino acid sequence revealed that the Hsp70 was grouped in the fungal cytosolic Hsp70s. Northern blot analysis demonstrated the upregulation of hsp70 expression during the mycelium to yeast phase transition. Upregulation was also observed during yeast or mycelial cells encountering heat shock condition at 39°C. Experimental analysis showed that the expression of hsp70 is temperature dependent. Contradictory, a severe heat shock condition at 42°C resulted in lowering the hsp70 transcript. Reverse transcription-polymerase chain reaction (RT-PCR) showed the accumulation of a large population of mature mRNA and small population of intron II-unspliced hsp70 mRNA in most cell types (conidia, mycelia and yeast). These results suggested that the Hsp70 may play an important role in environmental stress response and adaptation.

ABSTRACTThe oomycetous, fungus-like, aquatic organism Pythium insidiosumis the etiologic agent of pythiosis, a life-threatening infectious disease of humans and animals that has been increasingly reported from tropical, subtropical, and temperate countries. Human pythiosis is endemic in Thailand, and most patients present with arteritis, leading to limb amputation and/or death, or cornea ulcer, leading to enucleation. Diagnosis of pythiosis is time-consuming and difficult. Radical surgery is the main treatment for pythiosis because conventional antifungal drugs are ineffective. The aims of this study were to evaluate the use of Western blotting for diagnosis of human pythiosis, to identify specific immunodominant antigens of P. insidiosum, and to increase understanding of humoral immune responses against the pathogen. We performed Western blot analysis on 16 P. insidiosumisolates using 12 pythiosis serum samples. These specimens were derived from human patients with pythiosis who had different forms of infection and lived in different geographic areas throughout Thailand. We have identified a 74-kDa immunodominant antigen in all P. insidiosumisolates tested. The 74-kDa antigen was also recognized by sera from all patients with pythiosis but not by control sera from healthy individuals, patients with thalassemia, and patients with various infectious diseases, indicating that Western blot analysis could facilitate diagnosis of pythiosis. Therefore, the 74-kDa antigen is a potential target for developing rapid serodiagnostic tests as well as a therapeutic vaccine for pythiosis. These advances could lead to early diagnosis and effective treatment, crucial factors for better prognosis for patients with pythiosis.

Penicillium marneffei infection is an important emerging public health problem, especially among patients infected with human immunodeficiency virus in the areas of endemicity in southeast Asia, India, and China. Within these regions, P. marneffei infection is regarded as an AIDS-defining illness, and the severity of the disease depends on the immunological status of the infected individual. Early diagnosis by serologic and molecular assay-based methods have been developed and are proving to be important in diagnosing infection. The occurrence of natural reservoirs and the molecular epidemiology of P. marneffei have been studied; however, the natural history and mode of transmission of the organism remain unclear. Soil exposure, especially during the rainy season, has been suggested to be a critical risk factor. Using a highly discriminatory molecular technique, multilocus microsatellite typing, to characterize this fungus, several isolates from bamboo rats and humans were shown to share identical multilocus genotypes. These data suggest either that transmission of P. marneffei may occur from rodents to humans or that rodents and humans are coinfected from common environmental sources. These putative natural cycles of P. marneffei infection need further investigation. Studies on the fungal genetics of P. marneffei have been focused on the characterization of genetic determinants that may play important roles in asexual development, mycelial-to-yeast phase transition, and the expression of antigenic determinants. Molecular studies have identified several genes involved in germination, hyphal development, conidiogenesis, and yeast cell polarity. A number of functionally important genes, such as the malate synthase- and catalase-peroxidase protein-encoding genes, have been identified as being upregulated in the yeast phase. Future investigations pertaining to the roles of these genes in host-fungus interactions may provide the key knowledge to understanding the pathogenicity of P. marneffei.

SUMMARYPenicillium marneffei infection is an important emerging public health problem, especially among patients infected with human immunodeficiency virus in the areas of endemicity in southeast Asia, India, and China. Within these regions, P. marneffei infection is regarded as an AIDS-defining illness, and the severity of the disease depends on the immunological status of the infected individual. Early diagnosis by serologic and molecular assay-based methods have been developed and are proving to be important in diagnosing infection. The occurrence of natural reservoirs and the molecular epidemiology of P. marneffei have been studied; however, the natural history and mode of transmission of the organism remain unclear. Soil exposure, especially during the rainy season, has been suggested to be a critical risk factor. Using a highly discriminatory molecular technique, multilocus microsatellite typing, to characterize this fungus, several isolates from bamboo rats and humans were shown to share identical multilocus genotypes. These data suggest either that transmission of P. marneffei may occur from rodents to humans or that rodents and humans are coinfected from common environmental sources. These putative natural cycles of P. marneffei infection need further investigation. Studies on the fungal genetics of P. marneffei have been focused on the characterization of genetic determinants that may play important roles in asexual development, mycelial-to-yeast phase transition, and the expression of antigenic determinants. Molecular studies have identified several genes involved in germination, hyphal development, conidiogenesis, and yeast cell polarity. A number of functionally important genes, such as the malate synthase- and catalase-peroxidase protein-encoding genes, have been identified as being upregulated in the yeast phase. Future investigations pertaining to the roles of these genes in host-fungus interactions may provide the key knowledge to understanding the pathogenicity of P. marneffei.

ABSTRACTInfection by Penicillium marneffeiin human immunodeficiency virus-positive patients in India has recently been described; the aim of our study was to survey wild rodents and their associated environment in order to identify the natural populations of this fungus. Surveys recovered P. marneffeifrom the internal organs of 10 (9.1%) of 110 bamboo rats (Cannomys badius) examined from Manipur state, India, an area endemic for penicilliosis marneffei. Identification of the isolates was based on a detailed study of their morphological characteristics, in vitro conversion to fission yeast form, and exoantigen tests. Multilocus microsatellite typing (MLMT) of the isolates revealed five genotypes. No genotypes were shared between sample sites, and all bamboo rats were infected with a single genotype within sample sites, demonstrating spatial genetic heterogeneity. One MLMT genotype was identical to that seen in a human isolate, suggesting that either coinfection from a common source or host-to-host transmission had occurred. This demonstrates the utility of an MLMT-based approach to elucidating the epidemiology of P. marneffei.

ABSTRACTFor eukaryotic pathogens that have low levels of genetic variation, multilocus microsatellite typing (MLMT) offers an accurate and reproducible method of characterizing genetic diversity. Here, we describe the application of an MLMT system to the emerging pathogenic fungus Penicillium marneffei. Isolates used for this study were those held in the culture collections of the Centraalbureau voor Schimmelcultures, Utrecht, The Netherlands, and the Chiang Mai University Department of Microbiology, Chang Mai, Thailand. High genetic diversity and extensive spatial structure were observed among clinical isolates, with the geographical area of origin for each isolate strongly correlating with the occurrence of two deeply divided clades. Within each clade, multilocus linkage associations were highly significant and could be explained by genetically differentiated populations or by an exclusively clonal reproductive mode, or both. Our results show that southeast Asian penicilliosis is caused by a fungus with a complex population genetic structure. Furthermore, this MLMT system generates digital data that can be easily queried against a centrally held database via the internet (http://pmarneffei.multilocus.net/); this provides a powerful epidemiological tool for analyzing the underlying parameters that are responsible for the emergence of P. marneffeiin human immunodeficiency virus-positive populations.

ABSTRACTPythium insidiosumis a pathogen that causes disease in both animals and humans. Human infection is rare; however, when it does occur, most patients, especially those having underlying hemoglobinopathy syndromes, such as thalassemia, exhibit a severe form. We identified four isolates of P. insidiosum. Two were recovered from tissue biopsy specimens from thalassemic and leukemic patients, one was derived from brain tissue from a thalassemic patient, and another was isolated from a corneal ulcer from a fourth patient. Western blotting and an enzyme-linked immunosorbent assay (ELISA) were performed with a serum sample derived from one thalassemic patient. The methods used to identify the P. insidiosumisolates were based on morphology, nucleic acid sequencing, and a PCR assay. To confirm the identification, portions of the 18S rRNA genes of these four isolates were sequenced. The sequences were shown to be homologous to previously described P. insidiosumDNA sequences. In addition, PCR amplification of the internal transcribed spacer region specific for P. insidiosumwas positive for all four isolates. The ELISA with the serum sample from the thalassemic patient gave a positive result from a serum dilution of 1:800. Finally, Western immunoblotting with this serum sample showed positive immunoglobulin G recognition for proteins of 110, 73, 56, 42 to 35, 30 to 28, 26, and 23 kDa. The results of this study show that both molecularly based diagnostic and serodiagnostic techniques are useful for the rapid identification of human pythiosis. The predominant antigens recognized by Western blotting may be useful in the development of a more sensitive and specific diagnostic tool for this disease.

Adhesion of Penicillium marneffei conidia to the extracellular matrix protein laminin via a sialic acid-dependent process has previously been demonstrated. This study describes the interaction of P. marneffei conidia with fibronectin and examines the relationship of this process to the recognition of laminin via conidia. Immunofluorescence microscopy demonstrated that fibronectin bound to the surface of conidia and to phialides, but not to hyphae, in a pattern similar to that reported for laminin. Conidia were able to bind to fibronectin immobilized on microtiter plates in a concentration-dependent manner. However, binding to fibronectin (at any given concentration of protein and conidia) was less than that to laminin under equivalent conditions. Soluble fibronectin and antifibronectin antibody inhibited adherence of conidia to fibronectin in the plate adherence assay; soluble laminin also caused pronounced inhibition. Various monosaccharides and several peptides had no effect on adherence to fibronectin. However, N-acetylneuraminic acid abolished adherence to fibronectin, indicating that the interaction was mediated through a sialic acid-dependent process; the latter parallels observations of laminin binding by conidia. Fibronectin binding (and binding of laminin) was considerably reduced by prolonged preincubation of conidia with chymotrypsin, suggesting the protein nature of the binding site. Conidia from older cultures were more adherent to both immobilized fibronectin and laminin than conidia from younger cultures. Ligand affinity binding demonstrated the presence of a 20-kDa protein with the ability to bind both fibronectin and laminin. There would therefore appear to be a common receptor for the binding of fibronectin and laminin on the surface of P. marneffei, and the interaction described here maybe important in mediating attachment of the fungus to host tissue.

We report a case of pemphigus vulgaris in a 63‐year‐old woman. At the first onset, she developed herpetiform‐like skin lesions. Their histology showed eosinophilic spongiosis and intraepidermal blister formation with an infiltrate of eosinophils. Both direct and indirect immunofluorescence studies were negative. She remained in remission for 6 years. At the second onset, she developed bullous skin lesions; histological examination disclosed suprabasal acantholysis and infiltration of eosinophils. Direct immunofluorescence revealed IgG and C3 deposits at the cell surface, predominantly in the lower epidermis. Indirect immunofluorescence using normal human skin as a substrate demonstrated anti‐cell surface IgG antibodies at a titer of 1:160. Immunoblot analysis showed that the patient's serum reacted only with a 130kD protein. This case indicates that pemphigus vulgaris can follow herpetiform‐like skin lesions with negative immunofluorescence findings after a long remission time.

The cell-associated and extracellular enzymatic activities were examined in a total of 10 Penicillium marneffeiisolates. Both mycelia and yeast expressed alkaline phosphatase, acid phosphatase and naphthol-AS-BI-phosphohydrolase activities, whereas a variety of other enzyme activities, including trypsin, chymotrypsin and alpha-fucosidase were absent. There was some inter-isolate variation in both mycelia and yeast in the activities of other enzymes such as esterases and galactosidases. Enzyme activities did not change significantly over the course of culturing in three representative isolates.

ABSTRACTMannoproteins are important and abundant structural components of fungal cell walls. The MP1gene encodes a cell wall mannoprotein of the pathogenic fungus Penicillium marneffei. In the present study, we show that Mp1p is secreted into the cell culture supernatant at a level that can be detected by Western blotting. A sensitive enzyme-linked immunosorbent assay (ELISA) developed with antibodies against Mp1p was capable of detecting this protein from the cell culture supernatant of P. marneffeiat 104cells/ml. The anti-Mp1p antibody is specific since it fails to react with any protein-form lysates of Candida albicans, Histoplasma capsulatum, or Cryptococcus neoformansby Western blotting. In addition, this Mp1p antigen-based ELISA is also specific for P. marneffeisince the cell culture supernatants of the other three fungi gave negative results. Finally, a clinical evaluation of sera from penicilliosis patients indicates that 17 of 26 (65%) patients are Mp1p antigen test positive. Furthermore, a Mp1p antibody test was performed with these serum specimens. The combined antibody and antigen tests for P. marneffeicarry a sensitive of 88% (23 of 26), with a positive predictive value of 100% and a negative predictive value of 96%. The specificities of the tests are high since none of the 85 control sera was positive by either test.

ABSTRACTAdhesion of Penicillium marneffeiconidia to the extracellular matrix protein laminin via a sialic acid-dependent process has previously been demonstrated. This study describes the interaction of P. marneffeiconidia with fibronectin and examines the relationship of this process to the recognition of laminin via conidia. Immunofluorescence microscopy demonstrated that fibronectin bound to the surface of conidia and to phialides, but not to hyphae, in a pattern similar to that reported for laminin. Conidia were able to bind to fibronectin immobilized on microtiter plates in a concentration-dependent manner. However, binding to fibronectin (at any given concentration of protein and conidia) was less than that to laminin under equivalent conditions. Soluble fibronectin and antifibronectin antibody inhibited adherence of conidia to fibronectin in the plate adherence assay; soluble laminin also caused pronounced inhibition. Various monosaccharides and several peptides had no effect on adherence to fibronectin. However, N-acetylneuraminic acid abolished adherence to fibronectin, indicating that the interaction was mediated through a sialic acid-dependent process; the latter parallels observations of laminin binding by conidia. Fibronectin binding (and binding of laminin) was considerably reduced by prolonged preincubation of conidia with chymotrypsin, suggesting the protein nature of the binding site. Conidia from older cultures were more adherent to both immobilized fibronectin and laminin than conidia from younger cultures. Ligand affinity binding demonstrated the presence of a 20-kDa protein with the ability to bind both fibronectin and laminin. There would therefore appear to be a common receptor for the binding of fibronectin and laminin on the surface of P. marneffei, and the interaction described here maybe important in mediating attachment of the fungus to host tissue.

The efficiency of a modified flotation method for the isolation of Penicillium marneffeifrom soils has been evaluated. About 80% was recovered from sterilized soil freshly seeded with P. marneffei(100 conidia/1··5 g soil). When seeded non-sterile soil was used (at least 100 seeded conidia/1··5 g soil), P. marneffeicould be effectively recovered by employing a combination of the flotation method and the mouse inoculation method.

A case of cutaneous sporotrichosis is reported for the first time in Thailand. The infection occurred in a 33‐ year‐old Thai female who has been in good health and had no history of previous trauma or contact with any animals. Histopathology revealed pseudoepitheliomatous hyperplasia of the epidermis and a combination of granulomatous and pyogenic reactions in the dermis and subcutaneous tissue. Typical asteroid bodies (Splendore‐Hoeppli phenomenon) with central yeast cells were seen. Sporothrix schenckiiwas recovered from skin biopsy specimens. The patient responded well to the treatment with saturated solutions of potassium iodide within three months. No recurrence was seen after more than six months follow‐up. Es wird erstmals über eine Haut‐Sporotrichose in Thailand berichtet. Die Infektion fand sich am linken Arm einer gesunden Frau ohne vorangegangenes Trauma oder Kontakt mit Tieren. Histopathologisch wurde eine pseudoepitheliomatöse Hyperplasie der Epidermis und eine Kombination von granulomatöser und eitriger Reaktion in der Dermis und im subkutanen Gewebe gefunden. Typische Asteroid Bodies (Splendore‐Hoeppli‐Phänomen) mit einer zentralen Hefezelle wurden beobachtet. Sporothrix schenckiiwurde aus Hautbiopsie‐material isoliert. Die Patientin sprach gut auf die Behandlung mit gesättigter Kaliumjodid‐Lösung innerhalb von drei Monaten an. Wiihrend der mehr als sechsmonatigen Nachbeobachtungszeit trat kein Rükfall auf.

The patient was a 15‐year‐old male. Since birth, he has suffered from recurrent blistering, especially on the extremities. Histology and electron microscopic findings of the cutaneous lesions were compatible with those of dystrophic epidermolysis bullosa. Contracture and mobility limitation of the hands had gradually deteriorated. Prior to the admission to our clinic, both hands' contracture had been surgically treated 4 times in another hospital; however, after treatment with skin grafting, hand contracture recurred each time within one year. This time, surgical treatment was carried out for his left hand contracture using an abdominal skin flap under local anesthesia. In comparison with the free skin graft, the abdominal skin flap improved hand contracture for a longer time. Abdominal skin flap is recommended as a method for the treatment of hand contracture of patients with dystrophic epidermolysis bullosa.

ABSTRACTDisseminated infection with the dimorphic pathogenic fungusPenicillium marneffeiis increasingly seen among patients with AIDS in southeast Asian countries. Previous studies have demonstrated the presence of humoral immune responses to this fungus in patient sera; we have confirmed this work using sera from P. marneffei-infected patients (n= 21) to develop Western blots of P. marneffeicytoplasmic yeast antigen (CYA). P. marneffeiCYA was then partially purified by liquid isoelectric focusing, and fractions were subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blotting. Immunoenzyme development of the Western blots with pooled sera from patients with P. marneffeiinfection and with pooled sera from patients with aspergillosis (n= 20), candidiasis (n= 10), cryptococcosis (n= 9), and histoplasmosis (n= 11) revealed three antigens with relative molecular masses of 61, 54, and 50 kDa. These antigens were specifically recognized by the pooled sera from the P. marneffei-infected patients. The 61- and 54-kDa antigens were subsequently purified to homogeneity by preparative gel electrophoresis, and the 50-kDa antigen was partially purified by the same technique. N-terminal amino acid sequencing revealed that the 61-kDa antigen had a strong homology (87% identity) with the antioxidant enzyme catalase. The three antigens were then subjected to SDS-PAGE and Western blotting and to immunoenzyme development with individual patient sera; sera from 86% of P. marneffei-infected patients recognized the 61-kDa antigen, sera from 71% recognized the 54-kDa antigen, and sera from 48% recognized the 50-kDa antigen. These specifically recognized antigens are the first to be purified from P. marneffeiand can be used either singly or in combination to detect antibody responses in a large percentage of individuals infected with P. marneffei.

We report on a boy with Rapp-Hodgkin syndrome (RHS) or Rapp-Hodgkin ectodermal dysplasia. He had sparse, wiry, slow growing and uncombable hair, but no pili torti or pili canaliculi characteristic of RHS. He also had sparse eyelashes and eyebrows, and obstructed lacrimal puncta and epiphora. Bilateral bony external auditory canal stenosis led to hearing loss. The mouth was small with repaired bilateral cleft lip and palate. Oral manifestations included hypodontia, microdontia, unerupted mandibular premolars with well formed roots, large dental pulp spaces, enamel hypoplasia, multiple caries, glossy tongue, and congenital absence of lingual frenum and of sublingual caruncles including submandibular and sublingual salivary duct openings. Palmoplantar keratoderma, unerupted premolars, congenital absence of lingual frenum, sublingual caruncles, glossy tongue, and pili canaliculi seen in the patient are newly recognized findings of this syndrome. Overlapping findings of RHS ectrodactyly–ectodermal dysplasia–clefting syndrome (EEC), and ankyloblepharon–ectodermal defects–cleft lip and palate syndrome (AEC) are discussed. Am. J. Med. Genet 79:343–346, 1998. © 1998 Wiley-Liss, Inc.

Penicillium marneffei has been described recently as a cause of an emerging mycotic infection in HIV-infected patients. A PCR/hybridization assay was developed to rapidly identify this pathogen. The nucleotide sequence of the 631-bp region of 18S ribosomal DNA of P. marneffei was determined using the standard dideoxy chain termination method. An oligonucleotide probe was designed on the basis of the analysed sequences of P. marneffei and 18S rDNA sequences of other fungi in the GenBank database. A 631-bp PCR product was amplified using primers RRF1 and RRH1 from P. marneffei and seven other fungi, Penicillium spp., Aspergillus fumigatus, A. flavus, Histoplasma capsulatum, Cryptococcus neoformans, Candida albicans and C. krusei. A 15 oligonucleotide segment (Pm3) which was specific for P. marneffei was synthesized and used as a probe. Only the PCR products of P. marneffei isolates hybridized with the Pm3 oligonucleotide probe. The sensitivity of the assay was approximately 0·5 pg/μl and 0·1 pg/μl of DNA by PCR and Southern hybridization, respectively. The usefulness of this method as a diagnostic tool will require further studies.