Molecular cloning of the bovine MYOC and induction of its expression in trabecular meshwork cells

PURPOSE

Myocilin gene (MYOC) was identified as one of the disease-causing genes of primary open-angle glaucoma. This study was conducted to establish a system for the investigation of the biological role of MYOC in vitro by using bovine eyes, which are easy to obtain and have been widely used to examine the aqueous outflow system. The cDNA sequence of the bovine MYOC was determined and its expression in bovine eyes was examined with a quantitative polymerase chain reaction (PCR) assay.

METHODS

Bovine MYOC cDNA was obtained from cultured bovine trabecular meshwork cells, and part of its sequence was determined using a primer pair designed based on the known sequence of the human MYOC gene. The 3' and 5' ends of this sequence were determined using the method of 3' and 5' rapid amplification of cDNA ends. The induction of the MYOC gene in cultured bovine trabecular meshwork cells after exposure to dexamethasone was quantitatively examined with real-time quantitative PCR using a probe designed according to the sequence of the determined bovine MYOC gene.

RESULTS

Bovine MYOC protein was composed of 490 amino acids, which was 81.6% identical with that of human MYOC protein. Most of the amino acid residues of which mutation was reported to cause glaucoma were conserved in the bovine MYOC protein. After 2 weeks of treatment with 500 nM dexamethasone, expression of bovine MYOC mRNA was amplified 14-fold (14.1+/-5.1-fold, mean +/- SEM) measured by real-time quantitative PCR.

CONCLUSIONS

The cDNA sequence of the bovine MYOC gene had a high degree of similarity to that of the human MYOC gene. Investigation of the function of bovine MYOC may contribute to identifying the role of MYOC protein in the aqueous outflow system.

Hypotension and resistance to lipopolysaccharide-induced shock in transgenic mice overexpressing adrenomedullin in their vasculature

BACKGROUND

Adrenomedullin (AM) is a vasodilating peptide involved in the regulation of circulatory homeostasis and in the pathophysiology of certain cardiovascular diseases. To determine the extent to which chronic AM overproduction affects circulatory physiology under normal and pathological conditions, we used a preproendothelin-1 promoter to establish transgenic mouse lines overexpressing AM in their vasculature.

METHODS AND RESULTS

Transgenic mice overexpressing AM mainly in vascular endothelial and smooth muscle cells exhibited significantly lower blood pressure (BP) and higher plasma cGMP levels than their wild-type littermates. Blockade of NO synthase with N(G)-monomethyl-L-arginine elevated BP to a greater degree in AM transgenic mice, offsetting the BP difference between the 2 groups. Despite their lower basal BP, administration of bacterial lipopolysaccharide elicited smaller declines in BP and less severe organ damage in AM transgenic mice than in wild-type mice. Furthermore, the 24-hour survival rate after induction of lipopolysaccharide shock was significantly higher in the transgenic mice.

CONCLUSIONS

A chronic increase in vascular AM production reduces BP at least in part via an NO-dependent pathway. In addition, smaller responses to LPS in transgenic mice suggest that AM is protective against the circulatory collapse, organ damage, and mortality characteristic of endotoxic shock.

ADAMTS-1: a metalloproteinase-disintegrin essential for normal growth, fertility, and organ morphology and function

A disintegrin and metalloproteinase (ADAM) represents a protein family possessing both metalloproteinase and disintegrin domains. ADAMTS-1, an ADAM family member cloned from cachexigenic colon adenocarcinoma, is unusual in that it contains thrombospondin type I motifs and anchors to the extracellular matrix. To elucidate the biological role of ADAMTS-1, we developed ADAMTS-1-null mice by gene targeting. Targeted disruption of the mouse ADAMTS-1 gene resulted in growth retardation with adipose tissue malformation. Impaired female fertilization accompanied by histological changes in the uterus and ovaries also resulted. Furthermore, ADAMTS-1(-/-) mice demonstrated enlarged renal calices with fibrotic changes from the ureteropelvic junction through the ureter, and abnormal adrenal medullary architecture without capillary formation. ADAMTS-1 thus appears necessary for normal growth, fertility, and organ morphology and function. Moreover, the resemblance of the renal phenotype to human ureteropelvic junction obstruction may provide a clue to the pathogenesis of this common congenital disease.

Evidence for association between paraoxonase gene polymorphisms and atherosclerotic diseases

Paraoxonase 1 (PON1) is proposed to have an anti-atherogenic action. Two polymorphisms at the PON1 (M/L55 and Q/R192) have been shown to be associated with coronary artery disease (CAD). This conclusion is not drawn universally, however, and specific ethnic characteristics may be important determinants in this association. Recently two homologues of PON1 - PON2 and PON3 - were identified and Sanghera et al. demonstrated C/S311 polymorphism at PON2 was associated with the risk of CAD. Within that context, we investigated the association between the aforementioned three polymorphisms and CAD and ischemic stroke in a Japanese population. The study population included 431 control subjects, 210 CAD patients, and 235 ischemic stroke patients. Genotype distributions and allele frequencies of M/L55 and C/S311 were similar among the control and patient groups, whereas the R192 allele frequency was significantly higher (P<0.001) in CAD (75%) and ischemic stroke (76%) patients than in control subjects (65%). When confounding influences of other risk factors were controlled for by multivariate analysis, R192 remained an independent risk determinant (additive model: OR (95% CI), P value CAD: 2.01 (1.45-2.79), 0.0001; ischemic stroke: 1.84 (1.34-2.52), 0.0002 (three genotypes into calculation)). Taken together, our data indicate that the Q/R192 is principally associated with both CAD and ischemic stroke in Japanese.

Human glycine decarboxylase gene (GLDC) and its highly conserved processed pseudogene (psiGLDC): their structure and expression, and the identification of a large deletion in a family with nonketotic hyperglycinemia

Mutations in the glycine decarboxylase gene (GLDC) cause nonketotic hyperglycinemia (NKH), an in-born error of metabolism characterized by severe neurological disturbance. We have determined the structure of GLDC and of its pseudogene (psiGLDC) and studied their expression for a molecular analysis of NKH. The GLDC gene spans at least 135 kb and consists of 25 exons. All donor and acceptor sites adhere to the canonical GT-AG rule, except for the donor site of intron 21, where a variant form GC is used instead of GT. The transcription initiation site has been assigned to a residue 163 bp upstream from the translation initiation triplet by primer extension analysis. The psiGLDC gene has no intron and shares 97.5% homology with the coding region of functional GLDC, suggesting that psiGLDC is a processed pseudogene that arose from the GLDC transcript about 4-8 million years ago. RNA blotting analysis has revealed that GLDC is expressed in human liver, kidney, brain, and placenta. We have also examined a patient with NKH with no detectable GLDC mRNA in his lymphoblasts. Exons 1-3 of the functional GLDC gene from this patient are not amplified by polymerase chain reaction (PCR), whereas those from control subjects are. These results suggest a large homozygous deletion (at least 30 kb) in the patient. Furthermore, we have devised a semi-quantitative PCR to estimate the number of GLDC alleles by using psiGLDC as an internal control and have confirmed the homozygosity and heterozygosity of the deletion in the patient and his parents, respectively. Structural information of GLDC and psiGLDC should facilitate the molecular analysis of NKH.

Occurrence of serum M-protein species in Japanese patients older than 50 years based on relative mobility in cellulose acetate membrane electrophoresis

We investigated the occurrence of serum M-protein species in 2,007 Japanese patients older than 50 years of age. All sera samples were analyzed by cellulose acetate membrane electrophoresis. The relative mobility of an M-protein band was calculated by dividing the migration distance of M protein by that of albumin. M proteins were found to be present in 71 of 2,007 cases (3.5%). Men 80-89 years old showed the highest occurrence of M proteins, 11.0%. The relative mobility of M-protein bands, especially the band of the IgA-type M protein, increased as the patient's age advanced. The patients had higher levels of the IgG-type M protein than healthy Japanese subjects. We found that the occurrence of M-protein species in Japanese patients increases with their age. The IgG-type M protein was most frequently expressed among other types. The mobility of the M protein was greater in older patients probably because of aging-related changes in the carbohydrate chain of immunoglobulins composing an M-protein molecule.

Increase of intestinal calcium absorption and bone mineral density by heated algal ingredient (HAI) in rats

Active absorbable calcium (AAACa) produced by adding HAI (heated algal ingredient) to oyster shell calcium (AACa) is quite efficiently absorbed from the intestine and can increase bone mineral density in elderly osteoporotic patients. HAI was produced by heating the seaweed Cystophyllum fusiforme under reduced pressure, extracting with 6N HCL, and partially neutralizing it. Butanol-ethanol extraction then yielded active HAI fraction A, corresponding to about 1% in weight. The active HAI fraction increased intestinal Ca absorption as shown by a dose-dependent increase of plasma Ca in young male parathyroidectomized rats maintained on a low-Ca diet by administration through a stomach tube with a constant dose of AACa. The action of the active fraction A to maintain bone mass was then tested in young male rats kept on a low-Ca diet for 2 weeks. Bone weight, trabecular bone density, and strength-strain index as indices of bone strength measured by peripheral computed tomography (pQCT) tended to increase when the active HAI fraction was given along with Ca. HAI increased intestinal Ca absorption and prevented the decrease of bone density in rats kept on a low-Ca diet.

Pulmonary fat embolism syndrome: CT findings in six patients

PURPOSE

Our purpose is to describe the CT findings in pulmonary fat embolism syndrome (FES).

METHOD

Chest radiographs and CT scans of six patients with pulmonary FES were reviewed. Initial and follow-up CT findings were noted, and the extent of CT abnormalities was correlated with partial pressure of arterial oxygen (PaO2).

RESULTS

Focal areas of consolidation or ground-glass opacity and nodules were seen in all patients, predominantly in the upper lobes of the lungs. Association between these opacities and pulmonary vessels was indicated in three patients. In the lower lobes of all patients, gravity-dependent opacities predominated. Diffuse ground-glass opacity was noted in five patients. Follow-up CT scans showed rapid improvement in three patients, but the gravity-dependent opacity progressed. The extent of CT abnormalities correlated positively with PaO2 (r = 0.8, p < 0.05).

CONCLUSION

CT findings reflect the pathophysiology of this syndrome, which differs from that of simple capillary permeability pulmonary edema.

Dynamic character of the complex of human blood coagulation factor VIIa with the extracellular domain of human tissue factor: a normal mode analysis

As an attempt to investigate the dynamic interactions between plasma serine protease, coagulation factor VIIa (VIIa) and its cofactor, tissue factor (TF), we performed normal mode analysis (NMA) of the complex of VIIa with soluble TF (the extracellular part of TF; sTF). We compared fluctuations of Calpha atoms of VIIa or sTF derived from NMA in the VIIa-sTF complex with those of VIIa or sTF in an uncomplexed condition. The atomic fluctuations of the Calpha atoms of sTF complexed with VIIa did not significantly differ from those of sTF without VIIa. In contrast, the atomic fluctuations of VIIa complexed with sTF were much smaller than those of VIIa without sTF. These results suggest that domain motions of VIIa molecule alone are markedly dampened in the VIIa-sTF complex and that the sTF molecule is relatively more rigid than the VIIa molecule. This may indicate functions of TF as a cofactor.

Endothelin in the central control of cardiovascular and respiratory functions

1. Exogenously administered endothelin (ET) modulates the activity of cardiovascular and respiratory neurons in the central nervous system (CNS) and, thus, affects arterial blood pressure (ABP) and ventilation. However, a physiological role(s) for endogenous ET in the CNS has not been elucidated. To address this question, we examined ABP and ventilation in mutant mice deficient in ET-1, ETA and ETB receptors and endothelin-converting enzyme-1, which were made by gene targeting. 2. Respiratory frequency and volume was measured in mice by whole body plethysmography when animals breathed normal room air and hypoxic and hypercapnic gas mixtures. A few days after respiratory measurements, a catheter was implanted into the femoral artery under halothane anaesthesia. On the following day, the ABP of awake mice was measured through the indwelling catheter and heart rate was calculated from the ABP signal. After 2 h ABP measurement, arterial blood was collected through the catheter and pH and the partial pressures of O2 and CO2 were measured by a blood gas analyser. 3. Compared with corresponding controls, the mean (+/- SEM) ABP in ET-1+/- and ETB-deficient mice was significantly higher (118 +/- 2 vs 106 +/- 3 mmHg for ET-1+/- (n = 22) and ET-1+/+ (n = 17) mice, respectively; 127 +/- 3 vs 109 +/- 4 mmHg for ETB-/s (n = 9) and ETB+/s (n = 9) mice, respectively; P < 0.05 for both). In ET-1+/- mice, PCO2 tended to be higher and PO2 was significantly lower than corresponding values in ET-1+/+ mice. Under resting conditions, there was no significant difference in respiratory parameters between mutants and their corresponding controls. However, reflex increases of ventilation to hypoxia and hypercapnia were significantly attenuated in ET-1+/-, ET-1-/- and ETA-/- mice. 4. In another series of experiments in ET-1+/- mice, we found that sympathetic nerve activity (SNA) was augmented and reflex excitation of phrenic nerve activity (PNA) in response to hypoxia and hypercapnia was blunted. Attenuation of the reflex PNA response to hypercapnia was also observed in the medulla-spinal cord preparation from ET-1-/- mice. 5. Elevation of ABP in ETB-deficient mice was most likely due to a peripheral mechanism, because SNA and respiratory reflexes were not different from those in control animals. 6. We conclude that endogenous ET-1 plays an important role in the central neural control of circulation and respiration and that ETA receptors mediate this mechanism.

Disruption of ET-1 gene enhances pulmonary responses to methacholine via functional mechanism in knockout mice

Endothelin (ET)-1 has been shown to have various pathophysiological roles in the lung. Recently, it has been reported that ET-1 and a gene encoding ET-1 (Edn1) might be involved in airway hyperresponsiveness, which is a major feature of bronchial asthma. Meanwhile, it remains unclear whether ET-1 might be involved in airway remodeling in vivo. In the present study, we hypothesized whether ET-1 might play a role in airway remodeling, leading to altered responsiveness. To test this hypothesis, we investigated airway function in vivo and airway wall structure in Edn1(+/-) heterozygous knockout mice, which genetically produce lower levels of ET-1, and Edn1(+/+) wild-type mice. In the physiological study, enhanced responses in lung elastance and resistance to methacholine administration were observed in Edn1(+/-) mice, whereas there was no difference in serotonin responsiveness. In the morphometric study, there were no differences in either lamina propria or airway smooth muscle thickness between Edn1(+/-) mice and Edn1(+/+) mice. These findings suggest that ET-1 gene disruption is involved in methacholine pulmonary hyperresponsiveness via functional mechanism, but not airway remodeling, in mice. The ET-1 knockout mice may provide appropriate models to study diseases related to ET-1 metabolism.

Photoperiod-sensitive cytoplasmic male sterility in wheat: nuclear-mitochondrial incompatibility results in differential processing of the mitochondrial orf25 gene

An alloplasmic wheat line with the cytoplasm of Aegilops crassa expresses photoperiod-sensitive cytoplasmic male sterility (PCMS). Southern- and Northern-hybridization analyses showed that this line contains alterations in both the gene structure and transcription patterns of the mitochondrial gene orf25. In this study, the nucleotide sequence around the orf25 gene of Ae. crassa (CR-orf25) and common wheat (AE-orf25) was determined, and we found that the upstream region of CR-orf25 had been replaced by that of rps7 of common wheat (AE-rps7) through recombination. A novel open reading frame (orf48) is present upstream of CR-orf25. In these three genes, transcription was initiated from the consensus promoter motif of plant mitochondrial genes located in the upstream regions. Processing enzymes in Ae. crassa and common wheat cleave the respective precursor mRNAs, namely CR-orf25 and AE-rps7, at sites similar to that of the premature mitochondrial 26S rRNA. In contrast, the precursor mRNA is not effectively processed at the target sequence of CR-orf25 in the alloplasmic wheat line. Because major transcripts of the euplasmic CR-orf25 and AE-rps7 genes would result in a truncated orf48 product, one possibility is that the orf48 protein might disturb mitochondrial function at a specific stage and hence affect the expression of the PCMS trait.

Problems regarding the integration of medical images into the total hospital information system

Since 1989, the integration of medical images into the total hospital information system (HIS) has been investigated and developed at Kochi Medical School. The basic concept of the integration is that, in the same way they can view text based data, doctors can retrieve and view images using the PC terminals of the total HIS. The possibility of utilizing the PC terminals of the total HIS as image viewing stations was investigated. A test run was performed in the period from October 1995 to July 1997. The test run revealed that fast image access is crucial in order for the system to be useful for doctors. After making various improvements, the final system became well used in the clinical practice. However, in order to progress to the film-less stage, the final system still has three problems that must be solved: quality of the image display, operation of multi-exams, and quality assurance of the digital image.

Expression of plectin and HD1 epitopes in patients with epidermolysis bullosa simplex associated with muscular dystrophy

Plectin, a widespread cytoskeletal linker protein, is prominently expressed in basal keratinocytes of the epidermis. HD1, originally identified as a hemidesmosomal protein, has been suggested to be an isoform of or closely related to plectin, but the exact relationship between these proteins is unknown. Plectin has recently been identified as the gene/protein system at fault in epidermolysis bullosa simplex associated with muscular dystrophy (EBS-MD; OMIM# 226670). In this study, we examined the expression patterns of plectin and HD1 epitopes in the skin of four unrelated patients with EBS-MD confirmed to be caused by plectin gene mutations. By indirect immunofluorescence, all monoclonal antibodies (mAbs) to plectin (5B3, 10F6) or to HD1 (121, E2, K15, 156) bound to the epidermal basement membrane zone (BMZ) of normal human skin. In addition, immunostaining along the periphery of keratinocytes was detected with mAbs 5B3, 10F6 (antiplectin), K15 and 156 (anti-HD1), but not with mAbs 121 and E2 (anti-HD1). Immunolabeling for mAbs 5B3 and 10F6 (antiplectin) was absent in the skin of three patients who had premature termination codon mutations in the plectin gene in both alleles. In contrast, labeling was only slightly reduced in a patient who was homozygous for a 9-bp in-frame deletion mutation in the same gene. Interestingly, peripheral labeling of keratinocytes using mAbs K15 and 156 (anti-HD1) was clearly present in all the patients despite the disappearance of BMZ labeling. Quantitative analysis by postembedding immunoelectron microscopy demonstrated that both plectin and HD1 epitopes were localized in the inner plaque of hemidesmosomes with a mean distance of 110 and 120 nm from the plasma membrane, respectively. These results confirm the molecular heterogeneity of EBS-MD in terms of the expression patterns of plectin and HD1 epitopes which correlate with clinical severity, the pattern of plectin gene mutations and their consequences.

New approach to the medical information system for quality management in patient care: development of Problem Mapping System

A new type of medical information system named Problem Mapping System (P-Map) has been developed, which aids physicians with solving patients' problems. With this system, physicians can define the problems of in-patients, monitor their progress clearly, and share information efficiently. In P-map, a list of problems, such as disease names, can be set for each inpatient easily. The progress of each problem is clearly shown using progress lines on a time axis. Physicians can save the Subjective Objective Assessment Plan (SOAP) notes which are linked to each problem. At the final stage of patient care, a discharge summary can be made easily. With the aid of this system, the quality of patient care is improved due to the following: (1) physicians can make the best decision; (2) medical staff in the same team can provide the best medical treatment; (3) evaluation of each medical treatment is easy; (4) saved data can be used effectively for education and research; (5) the system can improve cooperation with other medical institutes by providing discharge summary information which can be distributed using e-mail; and (6) the system can improve patients' understanding for the purpose of informed consent by providing clear and well organized information to patients.

Intra-articular detachment of the Endobutton more than 18 months after anterior cruciate ligament reconstruction

We report a case of detachment of an Endobutton (Acufex Microsurgical, Mansfield MA) used for femoral fixation of a reconstructed anterior cruciate ligament. The Endobutton, which was confirmed to be in place on the suprapatellar space of the femur by radiograph 18 months postoperatively, was found in the popliteal space by radiograph 25 months after surgery. This is a rare complication, but our case suggests that the Endobutton should not be fixed too distal close to the femoral groove.

Efficacy and complications of the Gianturco-Z tracheobronchial stent for malignant airway stenosis

PURPOSE

To describe our experience using the Gianturco Z-stent (G-Z stent) for the management of malignant tracheobronchial stenosis, with special reference to complications.

METHODS

Thirty-six stents were used in 22 patients with 28 lesions. Thirteen patients were grade 5 according to the Hugh-Jones classification. The technical success rates, follow-up results, and complications were reviewed on the basis of the patients' charts and radiographs.

RESULTS

All stents were successfully placed in the ideal position without procedure-related complications. After the procedure, respiratory status improved in 95% (21/22) of patients, and performance status improved in 77% (17/22). Mean survival after stent placement was 15 weeks. Four patients suffered from increased thick secretions requiring multiple suctioning and aspiration by bronchoscopy. One of these patients died from asphyxiation 2 weeks after placement. Stent disruption and/or migration was observed in six patients. Of these six, four experienced life-threatening hemoptysis; all four had received aggressive anticancer treatment.

CONCLUSION

G-Z stents are useful for palliation of malignant tracheobronchial obstruction. However, complications of stent strut fracture and migration give cause for concern.

Endothelin and neural crest development

A series of gene targeting research have revealed novel roles of endothelins (ETs), peptides with potent vasoconstrictive and proliferative activities, in neural crest development in mammals. The phenotype of mice lacking the ET-1/ET-A receptor-mediated signalling affects cranial/cardiac neural crest-derived structures including the branchial arches and great vessels, and is highly similar to a set of the phenotypes of the avian neural crest ablation model. In contrast, mice lacking the ET-3/ET-B receptor-mediated signalling have defects in enteric neurons and melanocytes derived from trunk/vagal neural crest, resulting in megacolon and coat color spotting. Thus, both distinct pathways of the ET system seem to participate in the normal development of different neural crest lineages. Moreover, mutations in the human ET-3 and ET-B receptor genes have been identified in patients with Hirschsprung disease. As for the mechanisms involving the ET system in neural crest development, HANDs and Goosecoid, transcriptional factors essential for embryogenesis, have been suggested as key molecules downstream to the ET-mediated signalling in cranial/cardiac neural crest.

Simultaneous analysis of serum immunoglobulins in patients with M protein using cellulose acetate membrane isoelectric focusing

We developed a method for the simultaneous analysis of microheterogeneity of human serum IgG, IgA, IgM, IgD, and IgE, and serum protein pattern using cellulose acetate membrane isoelectric focusing, and analyzed in 11 healthy subjects and 67 patients with M protein (17 cases of multiple myeloma [MM] and 50 cases of monoclonal gammopathy of undetermined significance [MGUS]). Using this method, bands indicating the microheterogeneity of each immunoglobulin could clearly be detected.Among healthy subjects, the detected IgG, IgA, and IgM bands did not vary, but the detected IgE and IgD bands did vary. Therefore, IgA, IgM, and IgG were selected for comparison of serum immunoglobulins in MM and in MGUS. In the IgA-type M protein group, normal IgM and IgG bands were decreased in MM patients compared to MGUS patients, while the M band and other bands were increased in MM patients compared to MGUS patients, but the differences between the two groups were not significant. In the IgG-type M protein group, normal IgM, IgA, and IgG were significantly decreased in MM patients compared to MGUS patients. We examined the changes in electrophoretic pattern in six MM patients and eight MGUS patients with IgA-type M protein after neuraminidase treatment. The width of the M band in MM patients with IgA-type M protein decreased with neuraminidase treatment. On the other hand, the width of the M band in MGUS patients with IgA-type M protein increased with neuraminidase treatment. We concluded that the decrease of the normal immunoglobulins in MM patients with IgG type M protein could be detected by this method, and IgA type of M protein binding sugar chain were different between MM and MGUS patients.

The vertical displacement sign: a technique for differentiating between left and right ribs on the lateral chest radiograph

AIM

To evaluate a new approach to the differentiation of the right and left ribs, the vertical displacement sign, and to compare its efficacy with the big rib sign.

MATERIALS AND METHODS

One hundred and nine lateral chest radiographs that clearly showed both the gastric air bubble sign and the cardiac silhouette sign were retrospectively reviewed by two radiologists. Each study was evaluated by consensus. Each radiograph was assessed for suitability of reading with each technique. Suitable radiographs were then reviewed using both the big rib sign and vertical displacement sign independently.

RESULTS

Applicability of the vertical displacement sign [107 of 109 (98%)] was greater than that of the big rib sign [95 of 109 (87%)] (P = 0.0017). The accuracy of the vertical displacement sign [105 of 107 (98%)] was higher than that of the big rib sign [74 of 95 (78%)] (P < 0.001).

CONCLUSION

The vertical displacement sign seems to be a reliable technique for the differentiation of right and left ribs on the lateral chest radiograph and can be used as a complementary technique when the big rib sign is not applicable.

Localization of prostate-specific antigen-like immunoreactivity in human salivary gland and salivary gland tumors

Immunoreactivity of prostate-specific antigen (PSA), a kallikrein-like enzyme present in the seminal plasma, was demonstrated by indirect immunoperoxidase staining using a PSA antiserum in the apical cytoplasm along the luminal border of small-sized duct epithelial cells of the major salivary (parotid and submandibular) gland of both sexes (56/56, 100%). No PSA-like immunoreactivity was seen in large-sized duct epithelial cells and acinar cells. Minor salivary gland ducts were negative. When inflammatory and atrophic changes were observed, ductal expression of PSA-like immunoreactivity was decreased (12/37, 32%) and the site of intracellular localization often became diffusely cytoplasmic. The immunoreactivity was absorbed by human seminal plasma. Immunoreactivities of prostatic acid phosphatase and sex hormone receptors were undetectable in the salivary gland. Twenty-nine (34%) of 86 salivary gland tumors with ductal differentiation were immunoreactive for PSA mainly in the cytoplasm. A PSA monoclonal antibody ER-PR8 detected immunoreactivity in the prostate but not in the salivary glands or their tumors. Prostate-specific antigen-like immunoreactivity in small-sized (intercalated) duct epithelial cells of the major salivary gland and their tumors may be due to cross-reactivity of the antiserum with kallikrein-like substances.