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Biomedical subjects

M Mayumi

Publications and source records attributed to M Mayumi.

At least 217 records · Page 12Linked to original sources
PubMed1989

The loss of subtypic determinants in alleles, d/y or w/r, on hepatitis B surface antigen.

Hepatitis B surface antigen possesses the group-specific determinant called a and one or another member from each of two pairs of allelic determinants, d and y as well as w and r, thereby creating the four major subtypes, adw, adr, ayw and ayr. In the sequence of major surface antigen polypeptides made of 226 amino acid residues, lysine or arginine at amino acid position 122 specifies d or y determinant, and lysine or arginine at position 160 specifies w or r determinant, respectively. By means of site-directed mutagenesis and expression of mutant genes in cultured cells, the mechanism for the loss of subtypic determinants on surface antigens was investigated at the molecular level. A rare sample of surface antigen of subtype ad, devoid of w or r determinant, had asparagine at position 160. When it was converted to lysine, the surface antigen of subtype adw was obtained. Two samples of surface antigen were subtyped as ar. They lacked d determinant, despite having lysine at position 122 which usually specified it. They differed from all reported sequences of surface antigen in amino acid 144 or 145. They displayed d determinant when amino acid 144 was converted from glutamic acid to aspartic acid, or when amino acid 145 was changed from alanine to glycine. These results indicate that the key amino acid residue at position 122 or 160 is indispensable for the expression of subtypic determinants and that some distant residues are also crucially involved in conforming them.

Alleles↗
PubMed1989

Antigenic sites on the arginine-rich carboxyl-terminal domain of the capsid protein of hepatitis B virus distinct from hepatitis B core or e antigen.

The capsid protein of hepatitis B virus (P19) is made of 183 amino acids and carries the antigenic sites of hepatitis B core antigen (HBcAg) and hepatitis B e antigen (HBeAg) on the amino-terminal domain. The carboxyl-terminal domain of P19 (amino acids 150-183) is arginine-rich (47%) and faces the interior of the nucleocapsid for the binding with DNA. Monoclonal antibody was raised against an antigenic site on this protamine-like region of P19, which was distinct from HBcAg or HBeAg sites, and the novel antigenic site(s) was provisionally designated as hepatitis B inner core antigen (HBicAg). When P19 in a low concn (150 ng/ml) was immobilized on the solid surface, HBicAg sites were preserved, while HBcAg or HBcAg sites were no longer available on it. This allowed the detection of antibodies against HBicAg (anti-HBic), by sandwiching them between immobilized P19 and anti-IgG labeled with horseradish peroxidase. Anti-HBic was detected in sera from HBsAg carriers, typically those seropositive for antibody to HBeAg. A synthetic arginine-rich decapeptide, with a sequence of Arg-Arg-Arg-Gly-Arg-Ser-Pro-Arg-Arg-Arg, representing amino acids 150-159 of P19 and conserved in the majority of reported hepatitis B virus, absorbed the activity to bind with P19 in seven (44%) out of 16 sera containing anti-HBic. These results indicate that the decapeptide carries an HBicAg epitope and the remaining amino acid sequence of the arginine-rich carboxyl terminal domain (160-183) may be responsible for the other HBicAg epitopes.

Amino Acid Sequence↗
PubMed1989

Hepatitis B surface antigen with an excess or deficiency in subtypic determinants in sera from asymptomatic carriers in Japan.

Using the solid-phase enzyme immunoassay with monoclonal antibodies, hepatitis B surface antigen (HBsAg) was subtyped in sera from 5082 asymptomatic carriers who donated blood units at regional blood centers in Japan. Among them, 5004 sera contained HBsAg of a regular subtype, i.e., adw, adr, ayw or ayr, while 74 contained HBsAg with excessive subtypic determinants, such as adyw, adyr, adwr, aywr, or adywr. The presence of subtypic determinants on the selfsame particle was ascertained by sandwiching HBsAg between two monoclonal antibodies of distinct subtypic specificities. The remaining 4 sera contained HBsAg that possessed only one subtypic determinant, such as ad, ar or aw. HBsAg particles of atypical subtypes would have been given rise to by a point mutation in the S gene involving the codons regulating subtypic specificities.

Antibodies, Monoclonal↗
PubMed1989

Soluble low affinity Fc receptors for IgE in the serum of allergic and nonallergic children.

IgE-binding factors are thought to have regulatory activity in in vitro IgE synthesis. To obtain evidence of the participation of IgE-binding factors in in vivo IgE synthesis, the serum level of low affinity Fc receptors for IgE (sFc epsilon RII) (IgE-BFs) was examined in 41 nonallergic children and in 37 allergic children whose serum IgE levels were significantly higher than those of nonallergic children. The serum level of sFc epsilon RII showed a marked age-dependent variation. It was highest in infants and then decreased gradually with age. The serum level of sFc epsilon RII in allergic children was significantly higher than that of nonallergic children in early childhood (1128.0 +/- 323.8 vs 777.3 +/- 227.0 pg/ml, p less than 0.01 in infants (less than 1 y) and 851.8 +/- 270.0 vs 579.4 +/- 197.1 pg/ml, p less than 0.05 in children aged 1-2 y) but not in older children (3-15 y). Three allergic infants (less than 1 y) with serum sFc epsilon RII levels higher than the mean + 1 SD (1451.8 pg/ml) of all allergic infants (less than 1 y) had serum IgE levels (geometric mean 125.9 IU/ml) significantly higher than the other seven allergic infants (less than 1 y) (geometric mean 5.6 IU/ml, p less than 0.05). A close positive correlation between the serum level of sFc epsilon RII and the absolute number of Fc epsilon RII(+) peripheral blood lymphocytes was observed (Spearman's rank correlation coefficient = 0.79, p less than 0.001 in 27 allergic and Spearman's rank correlation coefficient = 0.72, p less than 0.001 in 19 nonallergic children). In conclusion, serum sFc epsilon RII may be derived mainly from Fc epsilon RII(+) lymphocytes, and may have relationship to the increased production of IgE in early childhood (0-2 y).

Adolescent↗
PubMed1989

Immunodeficiency associated with selective loss of helper/inducer T cells and hypogammaglobulinaemia in a child with intestinal lymphangiectasia.

A patient with intestinal lymphangiectasia (IL) was studied for his immunological abnormalities. The patient had hypoproteinaemia with severe hypogammaglobulinaemia. The results of lymphocyte subpopulation studies revealed a decrease of CD4+ cells and a decrease of surface immunoglobulin (sIg)-positive B lymphocytes. T cell functions determined by the proliferative responses against Concanavalin A (Con A) or phytohaemagglutinin (PHA) and by delayed type cutaneous hypersensitivity (DTH) response to purified protein derivatives (PPD) and PHA were normal. No immunoglobulin (Ig)-secreting cells were induced when his peripheral blood lymphocytes (PBL) were cultured with pokeweed mitogen (PWM). His T cells showed suppressor function to the PWM-induced differentiation of normal B cells. This suppressor activity was sensitive to 3000 rads irradiation. His B cells also failed to differentiate into Ig-producing cells with the help of normal T cells and PWM. Thus, in this patient, the decrease of Ig-synthesis in vitro could be attributed to suppressor T cells, lack of T helper cells and an intrinsic B cell defect. Therefore, this patient appears to have immunological abnormalities which differ from previously reported IL patients.

Agammaglobulinemia↗
PubMed1989

[Clinical evaluation of clarithromycin in pediatric patients].

A clinical evaluation of clarithromycin (TE-031, A-56268), a newly synthesized macrolide antibiotic, was made for its efficacy and safety in 30 patients with ages ranging from 8 month-old to 12 year- 2 month-old with mycoplasmal and bacterial infections. The obtained results are summarized below. 1. A pharmacokinetic study following oral administration of TE-031 at 10 mg/kg (granule) or 5.5 mg/kg (tablet) resulted in blood concentrations and urinary recovery rates higher than with other macrolides. 2. TE-031 was administered orally to 5 patients with Mycoplasma pneumonia, 21 patients with pneumonia or bronchopneumonia, 2 patients with pertussis and 2 patients with enterocolitis at daily dosages ranging 11.1-31.6 mg/kg divided into 3. Clinical evaluations of these 30 patients were as follows; excellent: 19 patients, good: 11 patients. The efficacy rate was 100%. 3. Neither clinical adverse reaction nor abnormal laboratory data was found in any of these 30 patients. 4. MICs of TE-031 against 10 strains of bacteria isolated from 10 patients with pneumonia or bronchopneumonia were as follows. MICs against 3, 2 and 2 out of 7 strains of Streptococcus pneumoniae were less than 0.025 microgram/ml, 0.05 microgram/ml and 0.10 microgram/ml, respectively. MIC against a strain of Haemophilus influenzae was 3.13 micrograms/ml. MICs of 2 strains of Branhamella catarrhalis were 0.20 microgram/ml. 5. TE-031 is considered to be a new useful and safe antibiotic in pediatric patient with an excellent bactericidal capacity.

Age Factors↗
PubMed1989

[Clinical evaluation of sulbactam/ampicillin in children].

Sulbactam/Ampicillin (SBT/ABPC), a combination at a fixed ratio of ABPC and SBT which is an irreversible inhibitor of beta-lactamase in a 2:1 ratio, was clinically evaluated for its efficacy and safety in 24 patients with ages from 5 month-old to 12 years old with bacterial infection. The results obtained are summarized as follows. 1. A pharmacokinetic study following 30 mg/kg SBT/ABPC administration by 30 minutes drip infusion or intravenous bolus injection showed that mean half-lives of SBT and ABPC were 48.9 minutes and 40.2 minutes, respectively, and mean urinary excretion rates of SBT and ABPC in the first 6 hours were 67.1% and 48.3%, respectively. 2. SBT/ABPC was administered to 14 patients with bronchopneumonia, 4 patients with tonsillitis, a patient each with acute upper respiratory infection, with submandibular lymphadenitis, with phlegmon, with enterocolitis, with pyelonephritis and with cystitis at a daily dosage of 88.2-133.3 mg/kg, divided into 3 or 4, by intravenous bolus injection or by 30 minutes drip infusion. Clinical responses of the 24 patients were as follows: excellent: 17 patients, good: 7 patients. The efficacy rate was 100%. 3. Neither clinical adverse reactions nor abnormal laboratory test values, except slight eosinophilia in a patient and an elevation of GOT, GPT in another were observed. 4. MICs of SBT/ABPC against 7 strong beta-lactamase producing strains isolated from some of the patients were as follows. MIC against a strain of Staphylococcus aureus was 3.13 micrograms/ml, MICs against 2 out of 5 strains of Branhamella catarrhalis were 0.10 microgram/ml and those of the remaining 3 strains were 0.20 microgram/ml. MIC against a strain of Haemophilus parainfluenzae was 3.13 micrograms/ml. 5. These data described above show that SBT/ABPC has excellent bactericidal capacity against beta-lactamase producing bacteria as well as beta-lactamase non-producing Gram-positive and negative bacteria and suggest that SBT/ABPC is a very useful antibiotic for pediatric patients.

Age Factors↗
PubMed1989

[Clinical studies on cefixime in pediatrics].

Clinical usefulness of cefixime (CFIX), a new oral cephalosporin antibiotic, in pediatric field was investigated. The results obtained were summarized as follows. 1. The clinical efficacy of CFIX was investigated in a total of 138 children including 49 with upper respiratory tract infections (RTI), 22 with acute bronchitis, 18 with pneumonia, 19 with scarlet fever and 21 with urinary tract infections (UTI). 2. Clinical effectiveness was excellent in 58, good in 60, fair in 14 and poor in 3, with an overall efficacy rate of 87.4%. The efficacy rate classified according to types of infection were 85.7% in upper RTI, 89.5% in acute bronchitis, 94.4% in pneumonia, 78.9% in scarlet fever, and 90.5% in UTI. 3. Out of the suspected causative organisms, 43 strains of a total of 50 strains isolated were eradicated. The bacteriological eradication rate was 86.0%. (Haemophilus influenzae 100%, Haemophilus parainfluenzae 100%, Streptococcus pyogenes 88.5%, Escherichia coli 85.7%). 4. One hundred forty four children were analyzed for side effect. Side effects were observed in 2 children (1.4%) with diarrhea in 1 and anorexia in another. Abnormal laboratory test results were recorded in 4 children (3.3%). The above results suggest that CFIX is a very useful new oral cephalosporin for the treatment of bacterial infections in children.

Adolescent↗
PubMed1989

[Clinical evaluation of cefodizime in children].

Cefodizime (THR-221, CDZM), a new parenteral cephalosporin, was evaluated for its efficacy and safety in 20 children with bacterial infections (Table 1), and the following results were obtained. 1. CDZM was administered in 3 or 4 divided doses at daily dosages ranging from 54.5 to 84.2 mg/kg administered by 30 minutes drip infusion or intravenous injection to 20 patients (7 cases of acute tonsillitis, 6 cases of pneumonia, 2 cases each of bronchitis and suppurative cervical lymphadenitis, and 1 case each of acute pharyngitis, acute enteritis and furunculosis) and the following clinical results were obtained: excellent, 7 cases; good, 11 cases; fair, 2 cases. The overall efficacy rate was 90% (Table 4). 2. MICs of CDZM against 15 strains of isolated organisms are shown in Table 2. MICs against all 7 strains of Haemophilus influenzae were less than 0.025 micrograms/ml. MIC against 1 out of 5 strains of Streptococcus pneumoniae was 0.05 micrograms/ml and those against 2 strains were 0.10 micrograms/ml and against the other 2 were 0.20 micrograms/ml. MICs against 3 strains of Staphylococcus aureus were 1.56, 25 and higher than 100 micrograms/ml, respectively. 3. No clinical adverse reaction was observed in any of the 20 patients. Eosinophilia was observed in 2 cases. A slight elevation of S-GOT was found in 1 patient (case No. 8) and moderate elevation of S-GOT and S-GPT in another (case No. 18) (Table 4). In case No. 18, the S-GOT and S-GPT activity improved after the administration of the drug was stopped.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1988

Regulation of Fc epsilon R2/CD23 gene expression by cytokines and specific ligands (IgE and anti-Fc epsilon R2 monoclonal antibody). Variable regulation depending on the cell types.

The regulation of human low affinity FcR for IgE (Fc epsilon R2/CD23) and the soluble Fc epsilon R2 [IgE binding factor (BF)] of monocyte (U937), T (ED), and B (JIJOYE) cell lines was examined by anti-Fc epsilon R2 mAb (H107, Mab176) and the cDNA probe for Fc epsilon R2. The effect of IL-4 and IFN-gamma on Fc epsilon R2 regulation was variable among these three cell lines. IL-4 and IFN-gamma enhanced the Fc epsilon R2 gene expression and the production of Fc epsilon R2 and IgE-BF on U937, whereas IL-4 and IFN-gamma had no significant effect on the Fc epsilon R2 expression on ED. On JIJOYE, IL-4 enhanced the Fc epsilon R2 and IgE-BF production on both protein and mRNA levels. In U937 and JIJOYE cells, there was a marked increase of Fc epsilon R2 mRNA after combined stimulation with IFN-gamma and IL-4. However, in JIJOYE cells, there was a dissociation between the surface expression of Fc epsilon R2 and Fc epsilon R2 mRNA treated with IFN-gamma plus IL-4. In these cells. IFN-gamma even down-regulated the IL-4-induced expression of surface Fc epsilon R2. Stimulation of JIJOYE cells with both IFN-gamma and IL-4 resulted in the increase of the IgE-BF in the supernatant, suggesting that IFN-gamma enhanced the release of IgE-BF from Fc epsilon R2. The results indicated that Fc epsilon R2 and IgE-BF expression is regulated by IFN-gamma at least on two different levels: on transcriptional levels and the levels of cleavage of the surface Fc epsilon R2 to release soluble Fc epsilon R2 (IgE-BF). Ligands binding to the Fc epsilon R2 such as IgE and anti-Fc epsilon R2 mAb enhanced the surface expression of Fc epsilon R2 on these Fc epsilon R2(+) cell lines. This was mainly due to the surface accumulation of the receptors on JIJOYE and U937. However, the stimulation of ED by H107 and anti-Fc epsilon R2 mAb significantly enhanced the mRNA expression, indicating that Fc epsilon R2 synthesis may also be up-regulated by the specific ligands in some cell types.

Antibodies, Monoclonal↗
PubMed1988

Typing hepatitis B virus by homology in nucleotide sequence: comparison of surface antigen subtypes.

The complete nucleotide sequences of the DNA of three hepatitis B virus (HBV) genomes of subtype adw, cloned from plasma samples of asymptomatic carriers living in the mainland and Okinawa Prefecture of Japan and Indonesia were determined. All three comprised 3215 bp and differed in sequence by only 3.9 to 5.6%. When these isolates were compared with the reported sequences of two HBV genomes of the same subtype derived from American carriers, however, the differences were greater (8.3 to 9.3% to an extent comparable with the nucleotide divergence between an HBV genome of subtype adw and that of a heterotypic subtype, such as adr, ayw or ayr. A total of 18 HBV genomes of various subtypes, including the three described here, 10 reported previously and five unpublished ones, were classified into four groups based on an inter-group divergence in nucleotide sequence of 8% or greater: group A (two adw genomes), group B (four adw), group C (three adw, four adr and one ayr) and group D (four ayw). Thus, the nine genomes of HBV subtype adw were distributed into three groups with considerably different sequences. These results indicate that the four major antigenically defined subtypes of envelope polypeptide do not reflect true genotypic variation of HBV. The fact that d to y, as well as w to r, subtypic change can be induced by an A----G point mutation at nucleotides 365 and 479 in the S gene, respectively, supports this view.

Amino Acid Sequence↗
PubMed1988

Postnatal changes in plasma burst-promoting activity (BPA) levels in preterm infants.

Two-stage cell culture assays were used to determine burst-promoting activity (BPA) levels in the plasma of untransfused premature infants during the early anaemic period. The plasma BPA levels decreased during the early phase of the postnatal fall in haemoglobin and the mean plasma BPA levels at 2 and 4 weeks of age were significantly lower (24 +/- 9% and 20 +/- 14%) than those of normal adults (53 +/- 17%). After 8 weeks of age, plasma BPA levels increased markedly in correlation with the recovery of erythropoiesis. Inhibitors of erythroid colony growth were not significantly elevated in the plasma of premature infants. These results suggest that BPA may act as a regulator of erythropoiesis in preterm infants along with erythropoietin.

Adult↗
PubMed1988

IgE receptor-bearing lymphocytes in allergic and nonallergic children.

Using a monoclonal anti-human IgE receptor (Fc epsilon R) antibody, the percentage of Fc epsilon R(+) cells among peripheral blood lymphocytes in children with or without allergic disorders was determined. The percentage of Fc epsilon R(+) cells in 63 nonallergic children was 4.3 +/- 1.5%, which did not vary with age and was equal to that of adults (4.2 +/- 1.2%). Allergic younger children (0-2 yr) showed a significantly higher percentage of Fc epsilon R(+) cells (7.7 +/- 3.0%) than nonallergic younger children (0-2 yr) (4.0 +/- 1.3%, p less than 0.001). Similarly, in allergic younger children, serum IgE levels (geometric mean = 58.9 IU/ml) were also significantly higher than those of nonallergic younger children (geometric mean = 2.0 IU/ml) (p less than 0.01). A positive correlation between the percentages of Fc epsilon R(+) cells and serum IgE levels was observed (Spearman rank = 0.88, p less than 0.01] in eight allergic younger children (0-2 yr) with serum IgE levels higher than 100 IU/ml. The increase in the percentage of Fc epsilon R(+) cells in allergic younger children (0-2 yr) was not a secondary phenomenon caused by serum IgE because serum IgE levels in these children were much lower than the concentration at which IgE enhance Fc epsilon R expression on lymphocytes. In conclusion, Fc epsilon R(+) lymphocytes may play a regulatory role in IgE synthesis in allergic younger children (0-2 yr).

Adolescent↗
PubMed1988

Regulation of Fc epsilon receptor expression on a human monoblast cell line U937.

Fc epsilon receptor (Fc epsilon R) expression on several human cell lines (U937, RPMI 8866, HL 60, THP-1, and Molt 4) and its regulation were examined by immunofluorescent analysis using a monoclonal anti-human Fc epsilon R antibody, H107. Phorbol ester (PMA), recombinant gamma interferon (IFN-gamma) and H107 itself enhanced Fc epsilon R expression on a FC epsilon R positive cell line U937, whereas these reagents did not induce FC epsilon R expression on the Fc epsilon R negative cell lines, Molt 4, HL 60 and THP-1. Dexamethasone not only suppressed by 50% the spontaneous Fc epsilon R expression on U937 cells but also completely inhibited the enhancement of their Fc epsilon R expression on U937 cells induced by PMA, IFN-gamma or H107. Dexamethasone caused a little suppression of Fc epsilon R expression by RPMI 8866 cells. The results showed that Fc epsilon R expression on a human monoblast cell line U937 was up- or down-regulated by a variety of physiological or pharmacological agents. These experimental systems provide a good model for the investigation of the regulatory mechanisms of Fc epsilon R expression.

Antibodies, Monoclonal↗
PubMed1988

[Clinical evaluation of sultamicillin fine granules in pediatric patients].

The clinical efficacy and the safety of sultamicillin (SBTPC) fine granules, which is a semisynthetic beta-lactam antibiotic for oral use with ester linked ampicillin (ABPC) and sulbactam (SBT), a beta-lactamase inhibitor, in a ratio of 1:1, were evaluated in 31 patients with ages from 6 months old to 10 years and 4 months old with various bacterial infections. The results obtained are summarized as follows. 1. In a pharmacokinetic study with a dose level of 10 mg/kg SBTPC, serum levels reached a peak in 1 hour after oral administration, with peak levels of 3.94 micrograms/ml for ABPC and 4.08 micrograms/ml for SBT. Half-lives of ABPC and SBT were 64.8 minutes and 63.6 minutes, respectively. The urinary excretion of ABPC over 6 hours was 66.2% and that of SBT was 60.4%. 2. SBTPC fine granules were administered orally to 1 patient with bronchitis, 9 patients with bronchopneumonia, 7 patients with tonsillitis, 4 patients with scarlet fever, 1 patient each with pharyngitis, otitis media, purulent parotitis, and urinary tract infection and 6 patients with skin and soft tissue infections at daily dosage levels of 26.1-31.6 mg/kg divided into 3 or 4. Clinical evaluations of these 31 patients were as follows, excellent: 20 patients, good: 10 patients, poor: 1 patient. The efficacy rate was 96.8%. 3. Diarrhea was observed in a patient with otitis media on the fifth day of SBTPC administration. No other clinical adverse reaction was observed in any of the remaining 30 patients. No abnormal laboratory data was found in any of 23 patients who were subjected to laboratory examinations for safety.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1988

Low burst-promoting activity (BPA) production by cord mononuclear cells is due to functional immaturity of monocytes.

Cord blood mononuclear cells produced lower burst-promoting activity (BPA) than adult peripheral blood mononuclear cells when stimulated with phytohemagglutinin (PHA). In order to examine the cellular basis of the low production of BPA by PHA-stimulated cord blood mononuclear cells in the context of the functional immaturity of T cells or monocytes, we studied BPA production by T cells or monocytes from cord blood and adult peripheral blood. Cord T cells produced as much BPA as adult T cells. Monocytes themselves did not produce significant BPA at the concentration used in this experiment (1 x 10(5)/ml). BPA production by adult T cells was significantly enhanced by the presence of autologous monocytes. BPA production by cord T cells was also enhanced by the presence of adult monocytes but not by that of cord monocytes. Cord monocytes did not enhance BPA production by adult T cells either. These results indicate that cord monocytes are primarily responsible for the low BPA production by PHA-stimulated cord mononuclear cells.

Erythropoiesis↗
PubMed1988

Antibody against the translation product of the pre-S2 region of hepatitis B virus and the resolution of infection after accidental needlestick exposure.

During a 5-yr period before the introduction of post-exposure immunoprophylaxis of hepatitis B virus (HBV), 363 medical personnel contracted infection after exposure to a contaminated needlestick. Among them, five (1.4%) developed a persistent carrier state, and they were followed for antibodies against translation product of the pre-S2 region (anti-pre-S2) by the enzyme immunoassay with native viral polypeptides. The consecutive seven cases in whom infection was terminated served as controls. In the acute phase, the levels of IgM and IgG anti-pre-S2 were significantly higher in the seven in whom infection resolved than in the five in whom infection persisted (mean sample:normal ratio, 11.1 +/- 4.4 vs 2.0 +/- 1.3 and 8.7 +/- 7.0 vs 3.0 +/- 1.1, respectively, p less than 0.05). In convalescence, 6 months after the normalization of serum transaminase, IgG anti-pre-S2 was detected in a high titer in the staff members with resolved infection (27.4 +/- 38.5), but was not detectable in those with persistent infection. On the basis of these observations, the intensity of humoral antibody response against the pre-S2 region product is closely correlated with the resolution of infection after exposure to HBV, and anti-pre-S2 persists in the circulation much longer than previously reported.

Accidents, Occupational↗