Inactivation of human immunodeficiency virus (HIV)-1 envelope-specific CD8+ cytotoxic T lymphocytes by free antigenic peptide: a self-veto mechanism?

Free peptide has been found to inhibit cytotoxic T lymphocyte (CTL) activity, and veto cells bearing peptide-major histocompatibility complex (MHC) complexes have been found to inactivate CTL, but the two phenomena have not been connected. Here we show that a common mechanism may apply to both. CD8+ CTL lines or clones specific for a determinant of the human immunodeficiency virus (HIV) 1 IIIB envelope protein gp160, P18IIIB, are inhibited by as little as 10 min exposure to the minimal 10-mer peptide, I-10, within P18IIIB, free in solution, in contrast to peptide already bound to antigen-presenting cells (APC), which does not inhibit. Several lines of evidence suggest that the peptide must be processed and presented by H-2Dd on the CTL itself to the specific T cell receptor (TCR) to be inhibitory. The inhibition was not killing, in that CTL did not kill 51Cr-labeled sister CTL in the presence of free peptide, and in mixing experiments with CTL lines of different specificities restricted by the same MHC molecule, Dd, the presence of free peptide recognized by one CTL line did not inhibit the activity of the other CTL line that could present the peptide. Also, partial recovery of activity could be elicited by restimulation with cell-bound peptide, supporting the conclusion that neither fratricide nor suicide (apoptosis) was involved. The classic veto phenomenon was ruled out by failure of peptide-bearing CTL to inactivate others. Using pairs of CTL lines of differing specificity but similar MHC restriction, each pulsed with the peptide for which the other is specific, we showed that the minimal requirement is simultaneous engagement of the TCR and class I MHC molecules of the same cell. This could occur in single cells or pairs of cells presenting peptide to each other. Thus, mechanistically, the inhibition is analogous to veto, and might be called self-veto. As a clue to a possible mechanism, we found that free I-10 peptide induced apparent downregulation of expression of specific TCR as well as interleukin 2 receptor, CD69, lymphocyte function-associated antigen 1, and CD8. This self-veto effect also has implications for in vivo immunization and mechanisms of viral escape from CTL immunity.

Bone composition and metabolism after hyperbaric oxygenation in rats with 1-hydroxyethylidene-1,1-bisphosphonate-induced rickets

We examined bone composition and metabolism after hyperbaric oxygenation (HBO) in Wistar rats with 1-hydroxyethylidene-1, 1-bisphosphonate (HEBP)-induced rickets. Twenty rats at 4 wk of age were divided into four groups of five rats each. The HEBP + HBO group received high dose (50 mg.kg-1.day-1) HEBP injections subcutaneously for 7 days and were then exposed to HBO for 7 days. The HEBP group received only high dose HEBP injection for the first 7 days. Control group A received neither HEBP nor HBO. Control group B received no HEBP injection and was exposed to HBO only for the second 7 days. Both bone mineral and hydroxyproline contents significantly increased in rats in the HEBP + HBO group as compared with the HEBP group. Alkaline phosphatase activity of bone, which is a marker of osteoblastic activity and bone formation, was high in the HEBP + HBO and HEBP groups compared with control groups A and B, although there was no difference between the former two groups. On the other hand, tartrate-resistant acid phosphatase activity, which is a marker of bone resorption, was lower in the HEBP + HBO group than in the HEBP group. These findings suggest that HBO suppresses bone resorption in high osteoblastic activity after the cessation of HEBP administration, and this phenomenon increases total bone mass.

[Thrombotic complication in the course of aplastic anemia-paroxysmal nocturnal hemoglobinuria syndrome; possible involvement of dysplasminogenemia (plasminogen Tochigi) in the pathogenesis of thrombosis]

A 44-year-old Japanese man having aplastic anemia (AA)-paroxyamal nocturnal hemoglobinuria (PNH) syndrome was referred to our hospital because of purpuras due to thrombocytopenia in July 1994. He suffered from pneumonia after admission, complicated with cerebral, splenic, and left renal infarction. Pulmonary infaction was also confirmed by perfusion lung scan. He had a plasma plasminogen (PLG) functional activity of 54.4% with a normal level of PLG antigen. The gel isoelectrofocusing pattern of the plasminogen derived from the patient showed 10 normal bands and 10 additional doublet bands with slightly higher isoelectric points than the normal components. Abnormal PLG is converted by urokinase to an inactive two-chain plasmin molecule. These findings were similar to those of a case with dysplasminogenemia (PLG Tochigi) reported by Aoki et al. He was given warfarin for the prevention of thrombosis in December 1994. As of October 1995, these was no recurrence of thrombosis. The cause of thrombosis in the present case have been the association with PNH, predisposition to PLG Tochigi, or the complication of pneumonia. This is the first report of AA/PNH syndrome associated with dysplasminogenemia.

Quantitative electromicroscope study of the oculomotor parasympathetic neurons projecting to the ciliary ganglion in cats: comparison of the synaptic (axon-somatic and axo-proximal dendritic) organization of anterior-dorsal and ventral cell groups

The synaptic organization of the oculomotor parasympathetic preganglionic neurons (OPNs), labeled retrogradely after a horseradish peroxidase (HRP) injection into the ciliary ganglion, was studied in cats by electron microscopy. We divided the OPNs into two groups, anterior-dorsal (ADG) and ventral (VG) cell groups, based upon physiological studies in cats suggesting that accomodation-related OPNs are predominantly located anterior and dorsal to the somatic nuclei of the oculomotor nuclear complex (i.e., the anteromedian and Edinger-Westphal nuclei, and the ventral central gray area), while pupillo-constriction-related OPNs are predominantly located ventral to the somatic nuclei (i.e., the ventral tegmental area). The synaptic organization of these two groups was quantitatively compared, using a nested analysis of variance to determine statistical significance (P < 0.05). Partial reconstructions of the labeled somata and proximal dendrites were made from tracings of electron micrographs of every 2nd section in serial ultrathin sections that included the nucleolus or were adjacent to sections that included the nucleolus. The mean number of boutons of apposition on a reconstructed labeled soma of VG was significantly greater than that of ADG (mean +/- SD; ADG, 5.3 +/- 3.3; VG, 8.6 +/- 3.2). The mean synaptic density on a VG soma was significantly greater than on an ADG soma (mean +/- SD; ADG, 3.74 +/- 2.11 counts/100 microns2; VG, 6.30 +/- 1.99 counts/100 microns2). The mean synaptic covering ratio on a VG soma was significantly greater than on an ADG soma (mean +/- SD; ADG, 5.21 +/- 2.91%; VG, 10.14 +/- 3.76%). The mean estimated number of boutons of apposition on a VG soma was significantly greater than on an ADG soma (mean +/- SD: ADG, 53 +/- 36; VG, 100 +/- 48). Boutons were classified on the basis of the shape of their synaptic vesicles as S-type (containing spherical clear synaptic vesicles) or P-type (containing both flattened and spherical clear synaptic vesicles). The significantly greater than on an ADG soma (mean +/- SD; ADG, 0.31 +/- 0.20; VG, 0.67 +/- 0.18). The differences demonstrated in this study reinforce, morphologically, the assumption of functional localization of OPNs, and further allow us to estimate the relative characteristics of the synaptic organization of accommodation-related OPNs and pupillo-constriction-related OPNs.

Cortical and subcortical SEPs following posterior tibial nerve stimulation

Intra-operative cortical and subcortical SEPs from the cerebral convexity and from the inter-hemispheric fissure were recorded following posterior tibial nerve (PTN) stimulation. Cortical and subcortical SEPs from the cerebral convexity after contra-lateral PTN stimulation consisted of N38 and P46, and their polarity reversed when the ipsi-lateral site was stimulated. On the other hand, cortical SEPs from the inter-hemispheric fissure always showed P38 and N46, whether the right or the left PTN was stimulated. Cortical and subcortical SEPs from the inter-hemispheric fissure showed clear cut polarity reversals. These findings provide good evidence for the existence of a tangential dipole oriented perpendicular to the inter-hemispheric fissure in the foot sensory area of the primary sensory cortex. SEPs recorded from the superficial part of the inter-hemispheric fissure showed smaller amplitudes and longer latencies than those of SEPs from the deeper regions. These findings suggest the existence of another dipole responsible for the generation of SEPs after PTN stimulation.

Inhibition of glutamine synthetase reduces ammonia-induced astrocyte swelling in rat

Astrocyte hypertrophy and swelling occur in a variety of pathophysiological conditions, including diseases associated with hyperammonemia. Ammonia is rapidly incorporated into glutamine by glutamine synthetase localized in astrocytes. We tested the hypotheses that (1) 6 h of hyperammonemia (500-600 microM) is adequate for producing astrocyte enlargement, and (2) astrocyte enlargement is attenuated by inhibition of glutamine synthetase with methionine sulfoximine. Pentobarbital-anesthetized rats received an intravenous infusion of either sodium or ammonium acetate after intraperitoneal pretreatment with vehicle, methionine sulfoximine (0.8 mmol/kg) or buthionine sulfoximine (4 mmol/kg), an analogue that does not inhibit glutamine synthetase. Hyperammonemia produced enlarged cortical astrocytes characterized by (1) decreased electron density of cytoplasmic matrix in perikaryon, processes and perivascular endfeet, (2) increased circumference of nuclear membrane, (3) increased numbers of mitochondria and rough and smooth endoplasmic reticulum in perikarya and large processes, and (4) less compact bundles of intermediate filaments. Pretreatment with methionine sulfoximine, but not buthionine sulfoximine, attenuated the decrease in cytoplasmic density and the increase in nuclear circumference; most perivascular endfeet remained as dense as occurred with sodium acetate infusion. However, increased numbers of organelles in expanded perikarya and large processes occurred after methionine sulfoximine treatment with and without ammonium acetate infusion. In separate groups of rats, hyperammonemia produced an increase in cortical tissue water content which was inhibited by methionine sulfoximine, but not buthionine sulfoximine. We conclude that clinically-relevant levels of hyperammonemia can cause astrocyte enlargement within 6 h in vivo characterized by both watery cytoplasm and increased organelles indicative of a cellular metabolic stress and altered astrocyte function. The watery cytoplasm component of astrocyte enlargement depends on glutamine synthesis rather than on ammonium ions per se, and is possibly caused by the osmotic effect accumulated glutamine.

The requirement for and mobilization of calcium during induction by sodium ascorbate and by hydrogen peroxide of cell death

The requirement for and mobilization of Ca2+ ions during induction of cell death by sodium ascorbate were compared with those during induction of cell death by hydrogen peroxide. When HL-60 cells were incubated with sodium ascorbate, a rapid increase in the intracellular concentration of Ca2+ ions and subsequent apoptotic cell death, characterized by cell shrinkage, nuclear fragmentation and cleavage of internucleosomal DNA to yield fragments that were multiples of 180-200 base pairs, were induced. However, these effects of sodium ascorbate were significantly reduced in Ca2+-depleted medium. By contrast, hydrogen peroxide induced similar apoptosis associated phenomena in the presence and in the absence of extracellular Ca2+ ions. The intracellular concentration of the reduced form of glutathione was not significantly affected and glutathione disulfide was undetectable during the early stages of apoptosis. These data suggest that sodium ascorbate and hydrogen peroxide initiate cell death by different mechanisms.

Sudden hearing loss as the initial manifestation of neurosarcoidosis

We report two cases of sudden hearing loss as the initial manifestation of neurosarcoidosis. The patients had no symptoms suggesting central nervous system or meningeal involvement. Eighth nerve involvement is an uncommon feature in patients with sarcoidosis. We discuss the pathophysiologic basis of sarcoid-induced hearing loss.

Sporothrix schenckii isolated from a cat in Japan

A yeast-like fungus isolated from a granulomatous and ulcerative skin lesion in a mongrel cat was mycologically examined. The isolate was identified as Sporothrix schenckii from the morphological findings and its pathogenicity in a mouse, confirming the first case of feline sporotrichosis in Japan. Fortunately, no transmission to humans occurred in this case, however the risk of humans contracting Sporothrix schenckii infection increases with the increase in the number of animals with sporotrichosis. Consequently when handling such animals protective clothing such as gloves should be worn to reduce the risk of transmission of the fungus through open wounds.

Neonatal meningitis caused by Bifidobacterium breve

We are reporting a male neonate with meningitis caused by Bifidobacterium breve. This is only the second case reported so far to our knowledge. The patient's clinical course was excellent and inflammatory indications, such as serum C-reactive protein, were weak. Although the antibiotics used for the patient were effective against this bacterium both in vitro and in vivo, two relapses occurred which might have been caused by an incomplete remission due to the low permeability of antibiotics through the blood-brain barrier under the very mild inflammation of the meninges, and also by the discrepancy between minimum bactericidal concentrations (MBC) and minimum inhibitory concentrations (MIC). Anaerobic meningitis is very rare, but it may exist in more than the reported cases. Anaerobic culture should be performed for patients with culture-negative purulent meningitis.

Promotion of callus formation by non-injurious mechanical stimulation in bean stems

We have examined the effect of non-injurious mechanical stimulation on callus formation of stem tissues. Mechanical stimulation by rubbing substantially promoted the wound-induced callus formation on the stems of beans (Phaseolus vulgaris L.). The promotion of callus formation also was observed in in vitro culture of the tissues excised from mechanically stimulated stems of beans. The results imply that mechanical stimulation induces some physiological changes preference for cell division in developing callus.

Effect of hyperbaric oxygenation on bone in HEBP-induced rachitic rats

The effect of hyperbaric oxygenation (HBO) treatment on rachitic change was studied using 4-wk-old, 1-hydroxyethylidene-1, 1-bisphosphonic acid disodium (HEBP-EHDP)-induced rachitic rats. After treatment, the dry weight, ash weight, Ca and P content, and bone mineral density of the hind leg bones were measured in each rat. These parameters were significantly increased in the rats that were treated with HBO after HEBP administration compared with those parameters in the rats that received HEBP alone. However, there was no significant differences between the rats treated simultaneously with HEBP and HBO and those that were treated with HEBP alone. These results were consistent with radiologic and histologic findings. Marked calcification in the center of the growth plate was revealed in the rats treated with HBO after HEBP administration. We suggest that intermittent high-pressure pure oxygen has a beneficial effect on osteogenesis in rachitic bone but does not prevent rachitic change.

p53 protein expression and gene analysis in clear cell adenocarcinoma of the vagina and cervix

OBJECTIVE

p53 is the most commonly mutated gene in human cancers. The objective of this study was to determine if clear cell adenocarcinomas (CCAs) of the vagina and cervix are associated with p53 gene mutations or alterations in p53 tumor-suppressor protein expression.

METHODS

Paraffin-embedded tissue specimens from 21 women (median age 22 years) with clear cell adenocarcinoma of the vagina or cervix were studied. Fifteen women had a prior history of in utero exposure to diethylstilbestrol. p53 protein expression was detected by immunohistochemical (IHC) analysis with monoclonal antibody DO-7 (Dako Corp.) which recognizes both wild-type and mutant p53 proteins. For p53 gene analysis, genomic DNA from malignant tissue was isolated and exons 4-10 were amplified by PCR and subjected to mutation screening by single-stranded conformation polymorphism (SSCP) analysis.

RESULTS

p53 protein was detected by IHC in tumors from 14 of 21 cases (67%). The observed p53 staining patterns were heterogeneous in both the proportion and intensity of tumor cells stained but were clearly overexpressed relative to the surrounding benign stroma. Metastatic tumors from 3 women with metastatic disease were also positive for p53 staining. SSCP analysis did not identify p53 mutations in any of the cases and strongly suggests that the tumors contained only wild-type p53 alleles.

CONCLUSIONS

Recent studies have demonstrated that wild-type p53 may accumulate in response to DNA damage which normally leads to growth arrest or programmed cell death. Our observations are consistent with the hypothesis that p53 overexpression in CCAs of the vagina and cervix is a response to generalized DNA damage, rather than a result of p53 protein half-life prolongation resulting from mutational inactivation of p53. Overexpression of wild-type p53 protein in vaginal and cervical CCA may relate to the more favorable prognosis of this subset of tumors in comparison to other gynecologic tumors containing mutated p53 genes.

A novel fluorescent derivative of glucose applicable to the assessment of glucose uptake activity of Escherichia coli

A novel fluorescent derivative of glucose was synthesized by reacting D-glucosamine and NBD-Cl. The TLC analysis of the reaction mixture showed the generation of a single spot with intense fluorescence (lambda Ex = 475 nm, lambda Em = 550 nm). The obtained novel fluorescent product, which was identified as 2-(N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)-2-deoxyglucose (2-NBDG) by 1H-NMR and FAB-MS spectrometries, was applied to the assessment of the glucose uptake activity of Escherichia coli B. 2-NBDG accumulated in living cells and not in dead cells. The uptake of 2-NBDG was competitively inhibited by D-glucose and not by L-glucose, which suggested the involvement of the glucose transporting system in the uptake of 2-NBDG. 2-NBDG taken into the cytoplasma of E. coli cells was supposedly converted into another derivative in the glucose metabolic pathway.

1,25-Dihydroxyvitamin D3 increased beta-adrenergic adenylate cyclase response of fetal rat keratinizing epidermal cells (FRSK cells)

Using fetal rat keratinizing epidermal cells (FRSK), the effects of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) on adenylate cyclase system were investigated. The beta-adrenergic adenylate cyclase response was significantly increased by the stimulation of 1 x 10(-7) M 1,25(OH)2D3. The effect was observed by 6 h and continued for at least 48 h. The 1,25(OH)2D3-induced beta-adrenergic augmentation effect was dose-dependent and the maximal response was observed at a concentration of 1 x 10(-7) M 1,25(OH)2D3. Other adenylate cyclase systems (adenosine, prostaglandin E2 and histamine) were not affected by treatment with 1,25(OH)2D3. The thymidine incorporation in FRSK cells was not significantly affected by 1,25(OH)2D3 treatment. Forskolin-induced cyclic AMP accumulation was significantly increased by 1,25(OH)2D3 treatment. Cholera toxin-induced cyclic AMP accumulation was moderately increased, but this was statistically not significant. Northern blot hybridization showed that none of the mRNAs (the beta 2-adrenergic receptor, the alpha subunits of the stimulatory or inhibitory guanine nucleotide binding proteins, Gs alpha, Gi2 alpha, Gi3 alpha) were significantly altered by 1,25(OH)2D3 treatment. We have already reported that the beta-adrenergic response was increased by dexamethasone and inhibited by retinoids in FRSK cells. The addition of both 1,25(OH)2D3 and dexamethasone to the incubation medium resulted in an additive augmentation. On the other hand, the beta-adrenergic augmentation by the 1,25(OH)2D3 treatment was suppressed by the addition of all trans-retinoic acids. Our results indicate that 1,25(OH)2D3 induces beta-adrenergic augmentation without an alternation of thymidine incorporation of FRSK cells.

[Serial changes of SPECT and MRI findings in a patient with herpes simplex encephalitis]

We report a case of herpes simplex encephalitis in which the patient was repeatedly examined by magnetic resonance imaging (MRI) and single photon emission computed tomography (SPECT). The patient was a 36 year-old woman who had been transferred to our institution 6 days after the onset of symptoms with mild consciousness disturbance, nuchal rigidity, and high fever. Cerebrospinal fluid examination revealed an elevated mononuclear cell count with normal sugar concentration. Intravenous aciclovir was started 7 days after the onset of symptoms. The initial plain computed tomography (CT) scans did not reveal any abnormal findings, but contrast enhanced CT the next day showed a slight enhancement effect around the affected middle cerebral artery. Serial MRI showed the initial high intensity lesion starting on the medial cortex of the temporal lobe, then spreading to throughout the entire temporal lobe. During this period SPECT showed a marked, broad hot spot in the temporal lobe. The medial temporal lobe was high density on the CT 15 days after the onset. As the encephalitic lesion spread more laterally, the hot spot on SPECT moved laterally and then decreased in activity. Eleven weeks after the onset, the MRI showed intracerebral vacuolization of the lesion and it appeared as a wide cold spot on SPECT. The cause of the hot spot seen in the acute period was thought to be vasoparalysis of the affected area rather than breakdown of the blood-brain barrier, or impaired washout of the isotope, because the SPECT images after acetazolamide administration showed the cold spot even in the subacute phase.

Mucosa-associated lymphoid tissue in middle ear and Eustachian tube in children

The presence of mucosal lymphoid follicles with germinal centers, so called mucosa-associated lymphoid tissue (MALT), in the Eustachian tube (ET) and middle ear (ME) was investigated in 23 human temporal bones containing the entire ET obtained from 23 children, 3 months to 10 years old at death. Greater numbers of MALTs were found in specimens from children with otitis media (OM) than from those without OM. MALT showed a wedge-shaped distribution through the ME and ET: in all 3 specimens that had MALTs in the ME, these tissues were seen throughout the ET; in all 4 specimens with MALTs in the bony portion of the ET, these tissues were present both in the tympanic and pharyngeal portions of the cartilagines ET; all 7 specimens that had MALTs in the tympanic half of the cartilagines ET had MALTs in the pharyngeal portion of the cartilagines ET as well. Furthermore, MALTs were noted in the pharyngeal portion of the ET in more than half of the specimens without OM but in none of the MEs of specimens without OM. These results support the hypothesis that persistent and recurrent inflammation in the nasopharynx spreads through the ET to play a role in the pathogenesis of chronic OM in children.

Relationships between fiber composition and NMR measurements in human skeletal muscle

The purpose of this study was to examine the relationships between the relative contents of phosphocreatine (PCr), inorganic phosphate (Pi), beta-adenosine triphosphate (ATP), and transverse relaxation time (T2) with fiber composition, which determined histochemically in the human skeletal muscle. The vastus lateralis muscles of 28 volunteers were subjected to phosphorus nuclear magnetic resonance (31P NMR) spectroscopy, magnetic resonance imaging (MRI) and muscle biopsy. Muscle fibers were divided into type I and type II fibers using myosin ATPase stain. A wide range of fiber composition levels were observed in the subjects (27.3-74.6% type I fibers). The PCr/ATP, Pi/ATP and (PCr + Pi)/ATP ratios were positively related to the percentage of type II fibers (r = 0.695, p < 0.001, r = 0.429, p < 0.05 and r = 0.773, p < 0.001, respectively). There was no correlation between fiber composition and the PCr/Pi ratio (r 0.127, n.s.) or intracellular pH (r = 0.305, n.s.). Moreover, no correlation was found between T2 and fiber type (r = 0.144, n.s.). These results suggest that 31P NMR can detect the differences in relative content of phosphates between type I and type II fibers, thereby noninvasively evaluating fiber composition in human skeletal muscle.

Targeting chemotherapy for malignant brain tumor using thermosensitive liposome and localized hyperthermia

Thermosensitive liposomes are microscopic vesicles that can contain drugs and release them effectively in response to hyperthermia. To deliver an antitumor drug specifically to brain tumor, the authors used thermosensitive liposomes containing cis-diamminedichloroplatinum (CDDP) in conjunction with localized brain heating. The authors then investigated the antitumor effect on rat malignant glioma. Rous sarcoma virus-induced malignant glioma cells were transplanted into the brains of Fisher rats. Ten days after tumor inoculation, the rats were assigned to one of six treatment groups: control, free CDDP, hyperthermia, free CDDP + hyperthermia, liposomes containing CDDP (CDDP-liposome), and CDDP-liposome + hyperthermia. Liposomes containing CDDP or free CDDP were injected via the tail vein. Brain tumor heating was administered by means of a radiofrequency antenna designed at our institute. The rats treated with CDDP-liposome + hyperthermia had the longest survival time and the tumor CDDP level of this group was the highest when compared to the other groups. Histopathological examination showed that tumor cells were necrotized but surrounding normal brain tissue remained undamaged. On the basis of these findings we suggest that the combination of thermosensitive liposome and localized hyperthermia may better focus antitumor drugs to the tumor, providing a significantly greater antitumor effect.

The relationship between the intrauterine environment and blood pressure in 3-year-old Japanese children

In 195 Japanese children the systolic pressure at 3 years of age was inversely correlated to the body weight at birth and positively correlated to the mothers' systolic pressure during pregnancy: the average systolic pressure in children whose body weight at birth exceeded 3510 g was 3.0 mmHg, which was lower than that of children whose body weight at birth was 2990 g or less. There was an increase of 0.12 mmHg in the children's systolic pressure with each increment of 1 mmHg in the systolic pressure of their mothers. The systolic pressure at 3 years in children of mothers who had had pretibial oedema during pregnancy (101.0 +/- 8.8 mmHg) was significantly higher compared with children whose mothers did not have oedema (96.6 +/- 9.6 mmHg).

[Angiotensin II receptors in a rat model of hypobaric hypoxic pulmonary hypertension]

Hypoxic pulmonary hypertension is characterized by profound remodeling of the walls of small pulmonary arteries: endothelial swelling and proliferation of media and adventitia to a degree that may narrow the lumen. The molecular mechanism responsible for these changes is unknown. Recent studies have demonstrated the existence of a vascular and cardiac renin-angiotensin system. This system can induce hypertrophy and proliferation of aortic smooth muscle cells and cardiac muscle cells in animal models of systemic hypertension. In the present experiments, Northern blot analysis and a receptor binding assay specific to angiotensin II (Ang II) receptors was used to study the pulmonary renin angiotensin system in a rat model of hypobaric hypoxic pulmonary hypertension. mRNA transcripts for the Ang II receptor AT(1A) were constitutively expressed, and specific binding of Ang II to the receptors occurred in lung tissue of control rats that breathed ambient air. After 3 days of hypobaric hypoxia (380 Torr), the AT(1A) mRNA level and the index of Ang II receptors had increased, but right ventricular hypertrophy was not still evident. Ang II receptors were significantly increased after 14 days of hypoxia, when histological evidence of pulmonary hypertension was observed. In addition, the Ang II level in pulmonary tissue was higher after 14 days of hypoxia than in normal controls. These findings suggest that the renin-angiotensin system in pulmonary tissue was activated in these rats, and that it contributes to the morphological changes observed in hypoxic pulmonary hypertension.

Molecular genetic analysis of clear cell adenocarcinomas of the vagina and cervix associated and unassociated with diethylstilbestrol exposure in utero

BACKGROUND

Prenatal exposure to the synthetic estrogen diethylstilbestrol (DES) is associated with the subsequent development of clear cell adenocarcinoma of the lower reproductive tract in young women, and data concerning the molecular genetic alterations involved in the etiology of this tumor type have not previously been reported. Such knowledge would be of potential value by providing insight into the molecular mechanisms of hormonal carcinogenesis in general, as well as by suggesting molecular markers for risk assessment in the estrogen-exposed population.

METHODS

A total of 24 samples of clear cell adenocarcinoma of the vagina or cervix, 16 associated with exposure in utero to DES and 8 with no history of DES exposure, were obtained as archival fixed and embedded tissue specimens. DNA was purified from these tissues and used to examine a number of biologically plausible molecular genetic endpoints for tumor specific alterations.

RESULTS

No evidence was found for mutations in the K-ras or H-ras protooncogenes, the Wilms' tumor (WT1) tumor suppressor gene, or the estrogen receptor gene. Sporadic overexpression of the p53 tumor suppressor gene was detected in some tumor cell nuclei by immunohistochemistry, but in the absence of detectable p53 gene mutation. Genetic instability as manifested by somatic mutation of microsatellite repeats was widespread in these tumors, with evidence of microsatellite instability in all DES-associated tumors examined, and in 50% of those tumors not associated with DES exposure.

CONCLUSIONS

These data are consistent with the hypothesis that the induction of genomic instability may be an important mechanism of DES-induced carcinogenesis.

[Introduction of molecular biology in respiratory medicine and its perspective]

I reviewed the change of respiratory medicine in the past several decades, overlapping with my own history of medical training and clinical and research works. In the 1950's when I graduated from the medical school and internship, the tuberculosis had been conquered effectively by the development of new antituberculous agents and improvement of nutritional state in Japan. Fibroptic bronchoscopy was introduced in the respiratory medicine in 1968, and computed tomography, in the 1970's, which gave us a good insight into pathological and biological aspects of various lung diseases in vivo. Molecular biology was brought in the respiratory medicine and our laboratory in the last decade, and my colleagues used it for genetic study of hereditary diseases such as alpha-1 antitrypsin deficiency and protein C deficiency, biochemical analysis of lung cancer and other pulmonary diseases, rapid detection of microorganisms, and so on. In the next step, gene therapy will come true in the near future, and I hope many intractable diseases such as lung cancer and interstitial pneumonia will be cured by the new technology and scientific knowledge.