PCR-based detection of one BamHI polymorphic site in the human T cell receptor delta gene TCRDV2

A polymorphic BamHI site was located in the coding region of the human T cell receptor delta gene TCRDV2. Two alleles defined by the absence or the presence of the BamHI site were detected by the polymerase chain reaction.

Effect of cell-derived growth factors and cytokines on the clonal outgrowth of EBV-infected B cells and established lymphoblastoid cell lines

Epstein-Barr virus (EBV) is a potent inducer of polyclonal B lymphocyte proliferation and is widely used as a tool for the establishment of B cell lines producing human monoclonal antibodies. However, because of low transformability, low clonability, and the inherent instability of EBV-infected B cells, valuable antibody-producing B cells are often lost during this procedure. We have here examined various cell-derived cytokines for their ability to enhance both the cellular outgrowth of newly infected B cells and the clonability of infected B cells and lymphoblastoid cell lines. Our results show that the murine thymoma cell line EL-4 is superior to peripheral blood mononuclear cells in both cellular outgrowth and cloning experiments, whereas monocyte-derived factors and monocyte cell lines were less capable than peripheral blood mononuclear cells in enhancing cellular outgrowth and cloning. Furthermore, the human T cell hybridoma cell line MP6 that secretes a B cell growth and differentiation factor, recently identified as an isoform of thioredoxin, is also capable of stimulating EBV-infected B cells and lymphoblastoid cell lines. Co-cultivation of EBV-infected B cells with MP6 cells significantly enhanced the cloning efficiency at the 1 cell/well level. The present results also suggest that one potential role of the MP6-derived thioredoxin could be the up regulation of IL-6 receptor expression in EBV-infected B cells.

Initiation and promotion of colonic aberrant crypt foci in rats by 5-hydroxymethyl-2-furaldehyde in thermolyzed sucrose

We have previously shown that thermolyzed sucrose in the diet promotes the growth of aberrant crypt foci (ACF) in the rat. HPLC analysis of the light caramel colored product showed that it contained 1% 5-hydroxymethyl-2-furaldehyde (HMF), confirmed by mass and NMR spectroscopy. To determine whether HMF was responsible for the promotion of ACF by thermolyzed sucrose, 45 F344 female rats were initiated with the colon carcinogen azoxymethane (AOM), and a week later were randomized to four groups receiving AIN-76 diets containing untreated sucrose, 20% thermolyzed sucrose, 20% butanol extracted thermolyzed sucrose (HMF free) or 1% HMF. Thermolyzed sucrose in the diet led to larger ACF as previously observed. Thermolyzed sucrose extracted to remove HMF, did not affect ACF size, but 1% HMF added to the diet led to a larger ACF both with relation to average size and number of ACF of larger sizes (P < 0.05). To determine whether HMF had initiating effects, 172 female F344 rats were given water, HMF (at doses to 300 mg/kg) or AOM (5 mg/kg) by gavage twice and the total number of ACF was scored 30 days later. The results demonstrated that HMF induces ACF in a dose-dependent manner (P < 0.02), though the effect was much weaker than that of AOM. We conclude that sugar heated under household cooking conditions may act as both an initiator and a promoter of colon cancer because of the presence of HMF.

Sucrose enhancement of the early steps of colon carcinogenesis in mice

The association of refined sugars and colorectal cancers and polyps in three recent case-control studies led us to investigate the effects of sucrose, fructose and glucose on colonic epithelial proliferation and sensitivity to carcinogenesis. CF1 and C57BL/6J mice were used; proliferation was assessed as vincristine-accumulated mitotic figures per crypt section; sensitivity to carcinogenesis was assessed as the number of aberrant crypt foci (ACF) per colon observed following the colon carcinogen, azoxymethane (AOM, 3 mg/kg and 5 mg/kg). Oral gavages of sucrose and fructose in CF1 mice (10 g/kg) increased colonic proliferation 16 h later (2.8 +/- 0.6 and 4.1 +/- 0.7 (mean +/- SEM) accumulated mitotic figures/crypt section), compared with glucose and water (1.0 +/- 0.2 and 0.4 +/- 0.1). Sucrose and fructose given 14 h prior to the AOM (5 mg/kg) increased the sensitivity of the colon to carcinogenesis (18.4 +/- 1.5 and 13.1 +/- 1.8 ACF/colon), compared with glucose and water (11.4 +/- 2.0 and 8.6 +/- 1.1). Similar results were observed with C57BL/6J mice. We conclude that dietary sucrose and fructose may represent risk factors for colorectal cancer through a direct effect of the sugars on colonic epithelial proliferation.

[Prevention of arrhythmia in rats by puhuang]

I.P. injection (5g crude drug/kg) of water extract of Puhuang (Typha orientalis) to S.D. rats can prevent ventricular fibrillation and sudden death caused by isoproterenol and also arrhythmia induced by the infusion of BaCl2. Water extract of Puhuang can clearly increase the survival rate and also raise the dosage of BaCl2 infusion necessary to cause the death of animals.

Herpesvirus infections in seals: a summary of present knowledge

This review summarises the occurrence of herpesvirus infections in pinnipeds and data from investigations carried out by the authors. These data demonstrate that herpesvirus isolates collected from harbour seals (Phoca vitulina Linnaeus, 1758) during the 1988 seal epidemic were almost indistinguishable from feline herpesvirus 1 and that Antarctic Weddell's seals (Leptonychotes weddelli Lesson, 1826) carry antibodies against seal herpesvirus from the north-western Europe seal epidemic. The significance of herpesvirus infections in seals is discussed.

Site-directed mutational analysis of human tumor necrosis factor-alpha receptor binding site and structure-functional relationship

In order to define the receptor binding site and the structure-functional relationship of tumor necrosis factor (TNF), single amino acid substitutions were made by site-directed mutagenesis at selected residues of human tumor necrosis factor, using a phagemid mutagenesis/expression vector. The recombinant TNF mutants were compared to the wild type TNF in assays using crude bacterial lysates, for protein yield, solubility, subunit trimerization, receptor binding inhibition activity, and in vitro cytotoxic activity. All mutants which did not form cross-linkable trimer also showed little cytotoxic activity or receptor binding inhibition activity, indicating that trimer formation is obligatory for TNF-alpha activity. Most mutations of internal residues yielded no cross-linkable trimer, while most mutations of surface residues yielded cross-linkable trimer. Mutations at surface residues Leu29, Arg31, and Ala35 yielded cross-linkable trimers with good activities, except proline substitutions which may cause conformational changes in the polypeptide chain. This suggested that these residues are near the receptor binding site. Mutations at other strictly conserved internal residues such as Ser60, His78, and Tyr119 form cross-linkable trimer with little activity. These mutations may indirectly affect the receptor binding site by forming trimers with undetectable abnormalities. Mutants of surface residues Tyr87, Ser95, Ser133, and Ser147 affect receptor binding and cytotoxic activity but not trimer formation, suggesting that these residues are involved directly in receptor binding. The fact that residues Arg31, Ala35, Tyr87, Ser95, and Ser147, located on the opposite sides of a monomer, are clustered at the intersubunit grooves of TNF trimer supports the current notion that TNF receptor binding sites are trivalent and are located at the three intersubunit grooves. However, our finding that Ser133, which is outside the groove, can also be involved directly in receptor binding suggested that the receptor binding sites of TNF may not be confined to the intersubunit grooves, but extended to include additional surface residues.

Aberrant crypt foci and microadenoma as markers for colon cancer

Foci of aberrant crypts similar to those seen in experimental animals exposed to colon carcinogens have been identified and quantified on the mucosal surface of fixed resections of human colon after methylene blue staining. Many of the foci in humans showed dysplasia on histologic examination and were considered to be microadenoma (MA). These lesions may be precursors for adenomatous polyps and colorectal cancer. Rats and mice initiated with azoxymethane, then fed diets containing sucrose or casein heated at 180 degrees C to stimulate normal cooking conditions, had three to five times more large MA after 100 days than controls. Thus, cooked sugar and protein contain promoters of the growth of colonic MA. 5-Hydroxymethylfuraldehyde was identified as a promoter in cooked sugar.

[Effects of propafenone, quinidine, and their combination on ventricular fibrillation threshold in dogs]

The effects of propafenone (Pro), a new Ic anti-arrhythmic agent (AAA), quinidine (Qui), and their combination on ventricular fibrillation threshold (VFT) and other electrophysiological properties were evaluated in 20 dogs. VFT was determined by a train of pulses, 4 ms in duration, delivered at 10 ms intervals. The results showed that in normal anesthetized, open-chest dogs: (1) Pro decreased VFT by 21.4%; (2) Qui increased VFT by 75.5%; (3) the Pro-induced decreased VFT was abolished by simultaneous administration of Qui; and (4) the above effects of the two drugs used separately or in combination on VFT were not related to their effects on ventricular effective refractory period and atrioventricular conduction time.

Promotion of aberrant crypt foci and cancer in rat colon by thermolyzed protein

BACKGROUND

We have previously shown that thermolyzed protein (casein) cooked with fat in the diet of the rat promotes the growth of aberrant crypt foci (putative precursors of colon cancer) assessed at 100 days.

PURPOSE

To determine how thermolysis affects this promotion, we examined thermolysis conditions, quantity of thermolyzed protein in the diet, and duration of thermolysis. To determine whether the previous finding of promotion of aberrant crypt foci corresponds to promotion of cancers assessed much later, we carried out promotion studies until colon cancers appeared.

METHODS

F344 rats were given an initiating dose of azoxymethane and were then randomly allocated to groups receiving diets differing in their quantity and quality of casein. The groups were examined for aberrant crypt foci and tumors in the colon.

RESULTS

Aberrant crypt foci were promoted by diets containing thermolyzed casein (180 degrees C, 2 hours). Promotion increased with increasing level of thermolyzed casein in the diet (to 20%) and with increasing thermolysis time (to 4 hours). The number of animals with polyps and cancers was higher in the animals receiving thermolyzed protein (2 hours), 16/23 versus 9/26 (P less than .05) and 10/26 versus 3/27 (P less than .05), respectively. The number of aberrant crypts per focus and the number of large aberrant crypt foci were higher in the tumor-bearing animals.

CONCLUSIONS

Thermolyzed casein promotes early colonic precursor lesions in a dose-dependent and thermolysis time-dependent manner; thermolyzed casein also promotes colon cancer.

IMPLICATIONS

The promoter formed on thermolysis could be involved in colon cancers associated with diets cooked at elevated temperatures, such as can occur with high-fat diets.

Vitamin A deficiency and inflammation: the pivotal role of secretory cells in the development of atrophic, hyperplastic and metaplastic change in the tracheal epithelium in vivo

We showed previously that the proliferation of hamster airway secretory cells decreases during vitamin A deficiency (VAD) but later increases when submucosal inflammation develops (Virchows Arch [B] 59:231-242, 1990). This observation has important biological implications since two morphological extremes (atrophy and quiescence versus hyperplasia and hyperproliferation) are reported in the literature for VAD tracheal epithelium in vivo. In the present study, histological slides of tracheal rings from 35-day-old control and VAD hamsters (Virchows Arch [B] 45:197-219, 1984) were reviewed again. Rings from VAD hamsters were selected based on the absence or presence of a florid submucosal inflammation. Quantitative analyses were made on the cartilaginous part of rings from the anterior third of the trachea. When inflammation was absent, a mucociliary pseudostratified epithelium was, for the most part, maintained. The mitotic rate (MR, 6 h colchicine blockade) of secretory cells was markedly reduced (29-fold) but that of basal cells was not changed significantly. Moreover, cell density was not changed by VAD but ciliated cells and secretory cells were decreased and basal cells were increased, proportionally. We call this "minimal morphological change." Thinning (atrophy) of the minimally changed epithelium was associated with focal cell sloughing. Small scattered foci of epidermoid metaplasia (multiple layers of highly keratinized cells which were extremely flat, so that the epithelium was thin and attenuated) were also seen. We call this "atrophic epidermoid metaplasia." When inflammation was present, hyperplastic changes (stratification and epidermoid metaplasia) predominated and cells were in mitosis at all epithelial levels (low, middle, superficial) except in the most superficial (terminally differentiated) squames. The tracheal epithelium was thickened and hypercellular. The cells were piled up at the stratified lesions, and epithelial height, cell density and epithelial MR were significantly increased compared with the non-inflamed VAD epithelium. The effects of VAD and inflammation on cell proliferation were analyzed further by studying 7 h bromodeoxyuridine (BrdU) labelling patterns of cells in VAD tracheal epithelium, with and without submucosal inflammation. In addition, inflammation was induced in "minimally changed epithelium" by mild mechanical injury. The BrdU labelling patterns confirmed that DNA synthesis by secretory cells is reduced markedly by VAD. However, this suppression is overidden by the influx of inflammatory cells (the nature of the stimulus is unknown). The results indicate that the morphological contrasts (atrophy and hyperplasia) seen in the trachea during VAD in vivo are related to extremes in proliferation rates of tracheal secretory cells, regulated by VAD alone (minimal replication) and by inflammation (maximal replication).

T cell receptor sequences from encephalitogenic T cells in adult Lewis rats suggest an early ontogenic origin

In the Lewis rat, the encephalitogenic determinant of myelin basic protein (MBP), residues 68 to 88, induces an alpha beta + T cell population whose TCR beta-chains are exclusively derived from the V beta 8 TCR gene family. As presented here, sequencing of these beta-chains has revealed the following. 1) There is an absolute restriction to a single V beta 8 family member, previously identified as V beta 8.2. This V region is used by only 10% of the V beta 8+ TCR found in normal unprimed mesenteric and cervical lymph node T cell populations. 2) There is a serine at residue 97 (in the CDR3 region of the beta-chain) which appears to be Ag-specific and is not found in normal populations of adult T cells. 3) There is a size restriction of these MBP-specific beta-chains, resulting from the addition and deletion of nucleotides in the CDR3 region, which tend to cancel each other out. 4) There is a paucity of N-region nucleotide additions in the J region of these MBP-specific beta-chains. Such a reduced number of nontemplate-added nucleotides has been associated with receptors that rearrange early during development and fail to add nucleotides due to a lack of terminal deoxynucleotidyl transferase at that time. These results have led us to propose that the selection of MBP-reactive autoimmune T cells is based on both the Ag and the time frame when these cells are generated and enter the peripheral T cell pool.

T cell receptor sequences from encephalitogenic T cells in adult Lewis rats suggest an early ontogenic origin

In the Lewis rat, the encephalitogenic determinant of myelin basic protein (MBP), residues 68 to 88, induces an alpha beta + T cell population whose TCR beta-chains are exclusively derived from the V beta 8 TCR gene family. As presented here, sequencing of these beta-chains has revealed the following. 1) There is an absolute restriction to a single V beta 8 family member, previously identified as V beta 8.2. This V region is used by only 10% of the V beta 8+ TCR found in normal unprimed mesenteric and cervical lymph node T cell populations. 2) There is a serine at residue 97 (in the CDR3 region of the beta-chain) which appears to be Ag-specific and is not found in normal populations of adult T cells. 3) There is a size restriction of these MBP-specific beta-chains, resulting from the addition and deletion of nucleotides in the CDR3 region, which tend to cancel each other out. 4) There is a paucity of N-region nucleotide additions in the J region of these MBP-specific beta-chains. Such a reduced number of nontemplate-added nucleotides has been associated with receptors that rearrange early during development and fail to add nucleotides due to a lack of terminal deoxynucleotidyl transferase at that time. These results have led us to propose that the selection of MBP-reactive autoimmune T cells is based on both the Ag and the time frame when these cells are generated and enter the peripheral T cell pool.

The hemagglutinin/esterase gene of human coronavirus strain OC43: phylogenetic relationships to bovine and murine coronaviruses and influenza C virus

The complete nucleotide sequences of the hemagglutinin/esterase (HE) genes of human coronavirus (HCV) strain OC43 and bovine respiratory coronavirus (BRCV) strain G95 were determined from single-stranded cDNA fragments generated by reverse transcription of virus-specific mRNAs and amplified by polymerase chain reaction. An open reading frame of 1272 nucleotides was identified as the putative HE gene by homology to the bovine coronavirus HE gene. This open reading frame encodes a protein of 424 amino acids with an estimated molecular weight of 47.7 kDa. Ten potential N-linked glycosylation sites were predicted in the HE protein of HCV-OC43 while nine of them were present in BRCV-G95. Fourteen cysteine residues were conserved in the HE proteins of both viruses. Two hydrophobic sequences at the N-terminus and the C-terminus may serve as signal peptide and transmembrane anchoring domain, respectively. The predicted HE protein of HCV-OC43 was 95% identical to the HEs of BRCV-G95 and other bovine coronaviruses, and 60% identical to the HEs of mouse hepatitis viruses. Phylogenetic analysis suggests that the HE genes of coronaviruses and influenza C virus have a common ancestral origin, and that bovine coronaviruses and HCV-OC43 are closely related.

Comparison of hemagglutinating, receptor-destroying, and acetylesterase activities of avirulent and virulent bovine coronavirus strains

Hemagglutinating and acetylesterase functions as well as the 124 kDa glycoprotein were present in the highly cell-culture adapted, avirulent bovine coronavirus strain BCV-L9, in the Norden vaccine strain derived from it, and in 5 wild-type, virulent strains that multiplied in HRT-18 cells but were restricted in several types of cultured bovine cells. The BCV-L9 and the wild-type strain BCV-LY-138 agglutinated chicken and mouse erythrocytes. The acetylesterase facilitated break-down of the BCV-erythrocyte complex with chicken but only to a minimal extent with mouse erythrocytes in the receptor-destroying enzyme test. Purified preparations of the vaccine and the wild-type strains agglutinated chicken erythrocytes at low titers and mouse erythrocytes at 128 to 256 times higher titers whereas receptor destroying enzyme activity was detectable only with chicken erythrocytes. When wild-type strains were propagated in HRT cells at low passage levels, they produced 5 x 10(5) to 4.5 x 10(6) plaque forming units per 50 microliters which agglutinated erythrocytes from mice but not from chickens. Diisopropylfluoro-phosphate moderately increased the hemagglutination titers, but completely inhibited the receptor destroying enzyme of purified virus of all strains. It had virtually no influence on the plaque-forming infectivity of the different BCV strains. The acetylesterase of strain BCV-L9 reacting in the receptor-destroying enzyme test was stable for 3 h at 37 and 42 degrees C. It was inactivated within 30 min at 56 degrees C while the hemagglutinin function of this strain was stable for 3 h at 37, 42, and 56 degrees C, but it was inactivated at 65 degrees C within 1 h.

Altered distribution of 1-2B7B antigen in basal cell carcinoma, squamous cell carcinoma and Bowen's disease

Skin lesions of basal cell carcinoma (BCC), squamous cell carcinoma (SCC) and Bowen's disease were immunohistochemically examined using the 1-2B7B monoclonal antibody, which recognizes a 120 kDa polypeptide component found in hemidesmosomes of normal human epidermis and hemidesmosome-like adhesion junction of vascular endothelial cells, to disclose altered characteristics of the interface between the tumor cell aggregate and stromal tissues of the epidermal neoplasms. In BCC, 1-2B7B antigen was rarely expressed at the tumor cell aggregate-stromal tissue interface, where poorly developed hemidesmosometonofibril complexes and a normal-looking lamina densa were detectable. In SCC and Bowen's disease, 1-2B7B antigen was expressed not only along the interface of the tumor nest and stromal tissue, but also in the intercellular space of the desmosomes and other adhesion junction structures that lack associating tonofibrils. In the invading front of SCC, 1-2B7B antigen had partly disappeared from the tumor cell aggregate-stromal tissue interface, where neither hemidesmosomes nor lamina densa were noted. The altered distribution of this hemidesmosomal component in the epidermal neoplasms seems to reflect aberrant interaction of neoplasmic cells and surrounding stromal tissue.

Extracellular matrix (mesoglea) of Hydra vulgaris. II. Influence of collagen and proteoglycan components on head regeneration

Hydra are characterized by having their body wall organized as an epithelial bilayer with an intervening acellular layer termed the mesoglea. As an extension of the previous study which indicated that mesoglea is a primitive basement membrane which has retained some characteristics of interstitial extracellular matrix, the present study was undertaken to analyze the role of mesoglea components during head regeneration in Hydra vulgaris. Studies were conducted that utilized drugs that affect collagen processing or secondary collagen structure (beta-aminoproprionitrile; 2,2'-dipydridyl; and cis-4-hydroxy-L-proline) and a drug that inhibits addition of glycosaminoglycan chains to proteoglycan core proteins (p-nitrophenyl-beta-D-xylopyranoside). These studies indicated that alterations in the structure of collagens or proteoglycans caused blockage of head regeneration in Hydra as monitored over a 48-hr period. Blockage of head regeneration was reversible once the drugs were removed, indicating that the drugs were not having a general toxic effect on the organism. Radiotracer studies also indicated that blockage of head regeneration was not simply due to a general depression of protein synthesis by the drugs. Various controls indicated that each drug was affecting mesoglea components under the conditions utilized in these studies. These observations indicate that preservation of normal mesoglea structure is required for Hydra head regeneration to proceed.

The hemagglutinin/esterase glycoprotein of bovine coronaviruses: sequence and functional comparisons between virulent and avirulent strains

The entire nucleotide sequences of the hemagglutinin/esterase (HE) genes specified by the highly virulent strain LY138 and the avirulent strain L9 of bovine coronavirus (BCV) were determined. These sequences were compared with recently published sequences of the HE genes of the Quebec and Mebus strains. A large open reading frame of 1272 nt encoding a protein of 424 amino acid residues was predicted. The putative esterase active site was conserved in the virulent and avirulent BCV strains, indicating that this domain is probably not a determinant for BCV virulence. Four amino acid substitutions occurred between the HE proteins of BCV-L9 and BCV-LY138 (leu to Pro at 5, Leu to Val at 103, Ser to Pro at 367, and Thr to Asn at 379). Monoclonal antibodies specific for the HE glycoprotein inhibited the hemagglutination and acetylesterase activities of BCV-L9, but showed no inhibitory effect on the acetylesterase activity of BCV-LY138. These results suggest that at least one epitope is located proximal to one of the three strain-specific amino acids. Four S-specific monoclonal antibodies inhibited hemagglutination but not acetylesterase activity of BCV-L9, implying that the S glycoprotein can promote hemagglutination of chicken erythrocytes in addition to the HE glycoprotein.

Extracellular matrix (mesoglea) of Hydra vulgaris. I. Isolation and characterization

Hydrozoans such as Hydra vulgaris, as with all classes of Cnidaria, are characterized by having their body wall organized as an epithelial bilayer with an intervening acellular layer termed the mesoglea. The present study was undertaken to determine what extracellular matrix (ECM) components are associated with Hydra mesoglea. Using polyclonal antibodies generated from vertebrate ECM molecules, initial light and electron microscopic immunocytochemical studies indicated the presence of type IV collagen, laminin, heparan sulfate proteoglycan, and fibronectin immunoreactive components in Hydra mesoglea. These immunocytochemical observations were in part supported by biochemical analyses of isolated Hydra mesoglea which indicated the presence of fibronectin and laminin based on Western blot analysis. Amino acid analysis of total mesoglea and some of its isolated components confirmed the presence of collagen molecules in mesoglea. Additional studies indicated the presence of (1) a gelatin binding protein in Hydra which was immunoreactive with antibodies raised to human plasma fibronectin and (2) a noncollagen fragment extracted from mesoglea which was immunoreactive to antibodies raised to the NC1 domain (alpha 1 subunit) of bovine glomerular basement membrane type IV collagen. These observations indicate that Hydra mesoglea is evolutionarily a primitive basement membrane that has retained some properties of interstitial ECM.

Monoclonal antibodies differentiate between the haemagglutinating and the receptor-destroying activities of bovine coronavirus

A relatively simple and sensitive method is described which enables the effect of monoclonal antibodies (MAbs) on the receptor-destroying enzyme (RDE) and the haemagglutination (HA) activity of bovine coronavirus (BCV) to be analysed in one assay. A lysate of HRT-18 cells infected with the L9 strain of BCV was found to have a higher RDE:HA ratio than purified virus. At 4 degrees C the lysate induced an HA pattern which completely disappeared upon raising of the temperature to 37 degrees C. This L9-infected cell lysate was used to determine the HA inhibition (HAI) titres of MAbs directed against the surface glycoproteins S and HE of BCV. Thereafter, the test plates were incubated at 37 degrees C to enable the ability of the MAbs to prevent elution of virus from BCV-erythrocyte complexes to be assessed. No inhibition of RDE was detectable with MAbs against glycoprotein S, which had HAI titres ranging from 1:16 to 1:128. On the other hand, MAbs directed against glycoprotein HE had similar HAI titres, but they inhibited elution of 8 HA units of BCV at titres of up to 1:65,000.

Patch testing in cases of eczema and dermatitis in Beijing, China

Of 124 patients with eczema and dermatitis patch tested by the European standard series of allergens in the period from April to October 1989, 59 cases showed sensitivity to 1 or more allergens. Potassium dichromate, nickel sulphate and cobalt chloride were the 3 major sensitizers, with a frequency of 17.9%, 13.8% and 10.6%, respectively. The office and factory workers showed a higher incidence of positive reactions than the student group. The environment of the office and the factory seems to be the potential source of exacerbating factors of eczematous skin disease.

RFLP detected by the transmembrane exon probe of the human immunoglobulin IGHA genes

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The IGLJ6 joining segment as a STS in the human immunoglobulin lambda light chain constant region gene locus (located at 22q11)

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