Efficacy of an ultrasonic surgical system for laparoscopic adrenalectomy

PURPOSE

We determine the value of an ultrasonic surgical system for laparoscopic adrenalectomy.

MATERIALS AND METHODS

We analyzed 16 patients who underwent laparoscopic adrenalectomy using the ultrasonic surgical system and compared the results with those of patients undergoing laparoscopic adrenalectomy without the system.

RESULTS

The system simplified exposure of the renal pedicles and inferior vena cava, and facilitated adrenal separation from the perinephric fat as well as dissection and identification of the adrenal vessels. Operating time was shorter and blood loss was also less with use of the ultrasonic surgical system.

CONCLUSIONS

The ultrasonic surgical system simplified laparoscopic adrenalectomy and made the operation much safer.

[Influence of pneumoperitoneum on respiratory function during urological laparoscopic surgery]

PURPOSE

To determine the influence of pneumoperitoneum on respiratory function during urological laparoscopic surgery.

MATERIALS AND METHODS

We performed laparoscopic surgery on 82 patients, 45 of these patients were examined in detail of the effect of pneumoperitoneum on the respiratory function. Of these 45 patients, 14 patients received lymphadenectomy and 31 patients received adrenalectomy. For comparative analysis, 4 patients with laparoscopic cholecystectomies were also examined. Under general anesthesia, carbon dioxide tension (PaCO2) was analyzed before, during, and after the pneumoperitoneum. The data were analysed along with 4 factors; the patient's spirographic parameters, alveolar-arterial gas difference (AaDO2), insufflation pressure for the pneumoperitoneum, and operating time.

RESULT

After starting the pneumoperitoneum, PaCO2 levels rose significantly. The PaCO2 levels of patients underwent laparoscopic adrenalectomy were higher than that of patients underwent laparoscopic cholecystectomy. The preoperative vital capacity and forced expiratory volume in one second (FEV1.0) did not show a significant difference of increase in the degree of PaCO2 increase. In contrast, the important factors that were closely related to the elevation of PaCO2 were preoperative AaDO2 and intraoperative insufflation pressure. Patients with high preoperative AaDO2 (> 10 torr) showed a significant increase in PaCO2 levels after pneumoperitoneum. When insufflation pressure was high (> = 10 mmHg), there was a significant rise of PaCO2 after pneumoperitoneum. In all patients whose operating time was 300 minutes or more, high levels of PaCO2 continued on the next day after surgery.

CONCLUSION

We should still carefully observe the insufflation pressure, operating time, and other ventilation conditions during laparoscopic surgery.

Molecular cloning and characterization of a mouse oviduct-specific glycoprotein

In the present study, we have isolated the cDNA for the mouse oviduct-specific glycoprotein (MOGP) by screening the mouse oviduct cDNA library with the bovine oviduct-specific glycoprotein (BOGP)-cDNA probe and by the 5' rapid amplification of the cDNA end (5'RACE). The total length of cDNA was determined to be 2525 base pairs (bp) by sequence analysis. The coding region contained 2163 bp translating to 721 amino acids. Based on comparisons with the N-terminal amino acid sequences of purified-BOGP and of hamster oviduct-specific glycoprotein (oviductin), it was inferred that the derived amino acid sequence contained a signal peptide region of 21 amino acids and a mature MOGP (core protein) region of 700 amino acids (76,515 daltons). It was also inferred that the mature MOGP contained three potential N-linked glycosylation sites and 24 possible O-linked glycosylation sites, and had the unique seven-residue repeat sequence (21 repeats) within the predicted sequence in the C-terminal side. The amino acid sequence of a portion of MOGP was highly homologous to that of BOGP (71% identity), baboon oviduct-specific glycoprotein (61% identity), and human oviduct-specific glycoprotein (77% identity). Significant homologies were also observed with two mammalian secretory proteins that were reported as a mammalian member of a chitinase protein family. Northern blot hybridization with a DIG-labeled probe indicated that a single message of 2.8 kb was present in total RNA prepared from oviductal tissue. In situ hybridization using MOGP-cDNA showed that a MOGP message was only detected in the oviductal epithelial cells. These results strongly suggest that a significant degree of homology exists among oviduct-specific glycoproteins of various mammalian species.

Structural elucidation of aculeximycin. III. Planar structure of aculeximycin, belonging to a new class of macrolide antibiotics

The planar structure of aculeximycin (1) produced by Streptosporangium albidum has been determined by spectral methods and chemical degradations such as 1,8-diazabicyclo[5,4,0]undec-7-ene (DBU)-methanol reaction, ozonolysis, and periodative oxidation. The antibiotic consists of a 30-membered polyhydroxy lactone ring, an alpha, beta-unsaturated ester group, an intramolecular hemiketal, an oligosaccharide (aculexitriose), a neutral sugar and an amino sugar. The structure of aculeximycin is closely related to those of sporaviridins produced by Streptosporangium viridogriseum. We consider that aculeximycin and sporaviridins belong to a new class of macrolide antibiotics, which is different from the polyol macrolides produced by Streptomyces.

[Epidural injection for postoperative pain relief after thoracoscopic surgery]

For the pain relief after thoracoscopic surgery, the epidural injection of buprenorphine was performed in 46 cases. In 28 cases, intermittent injection was performed before awaking from anesthesia. The effect was excellent in 6 cases, who were free from pain without any more injection after returning to the ward, and good in 27 cases, who sometimes felt dull pain and had another analgetics (intermittent epidural injection in 16 cases, intermittent epidural injection and another medication in 5 cases). In 18 cases, continuous injection was performed. The effect was excellent in 9 cases and good in 9 cases. It was concluded that the epidural injection had effective analgesic effect after thoracoscopic surgery, both in intermittent injection group and continuous injection group. For limited medication, the intermittent epidural injection was considered the first choice after thoracoscopic surgery.

Estradiol-17 beta as an initiation modifier for radiation-induced mammary tumorigenesis of rats ovariectomized before puberty

This investigation evaluated the roles of estradiol-17 beta, progesterone and prolactin in the initiation of mammary tumorigenesis by irradiation. Sixty day old Wistar-MS rats ovariectomized bilaterally at 23 days of age were injected daily with olive oil, estradiol-3-benzoate (E2B), progesterone or haloperidol for 14 days, and were then irradiated with gamma-rays (260 cGy) on the morning following the last injection. Diethylstilbestrol pellets were administered by implantation 30 days after the irradiation. Following treatment with E2B, the incidence of mammary tumors was increased 2.2-fold, in comparison with that in the corresponding control rats. Bilateral ovariectomy before puberty caused the mammary glands of adult rats to atrophy, and a low degree of differentiation with long narrow ducts was observed in whole mounts. The DNA synthesis in the mammary glands and serum prolactin level of E2B-treated rats were markedly increased and the terminal ducts showed distinctly increased differentiation into terminal end buds and alveolar buds with prolactin receptors. When progesterone, another ovarian hormone, or haloperidol, a dopamine antagonist in adenohypophysis, was injected into the rats under estrogen-free conditions, neither expression of prolactin receptors nor stimulation of DNA synthesis was observed in the mammary glands, and the incidence of mammary tumors induced by irradiation was lower than that observed in rats treated with E2B. Combined treatment with E2B and progesterone resulted in a reduction in the incidence of mammary tumors and in serum prolactin levels compared with those in E2B alone, in spite of the synergistic effects on prolactin receptor concentration and DNA synthesis by the two hormones. On the other hand, concurrent administration of haloperidol did not reduce the E2B-induced tumor incidence or prolactin concentration in serum. Many of the mammary tumors which developed in the ovariectomized rats were of the ER(-)PgR(-) type. The incidence of development of ER(+)PgR(+) tumors was increased by treatment with E2B before the irradiation, and no ER(-)PgR(-) tumors were observed in this group. Our results suggest that estrogen is a direct or indirect sensitizer for tumor initiation by radiation, and is also one of the regulatory factors for hormone dependence of radiation-induced mammary tumors.

Peripheral nerve pathology in Niemann-Pick type C mouse

The sciatic nerve of the mouse mutant with Niemann-Pick type C disease (NPC mouse) was investigated using light and electron microscopy, and teased-fiber preparations. As early as postnatal day 20, when clinical symptoms were not yet apparent, focal paranodal swellings with an accumulation of small myelin figures in the Schwann cell cytoplasm were noted. These paranodal changes were more pronounced in the distal segment and became progressively conspicuous with increasing age. The morphometric analysis revealed a hypomyelination of large myelinated fibers in the NPC nerves at 70 days, whereas an essentially similar histogram pattern was noted in both control and NPC nerves at 20 days, suggesting progressively defective utilization of cholesterol in the NPC nerves with age. Intraxonal accumulation of dense bodies was noted in older mice, but no segmental demyelination or Wallerian type of axonal degeneration was observed at any age. The changes noted in the paranodal regions in the NPC mouse closely resemble those found in rats treated with an inhibitor of cholesterol biosynthesis, as well as those seen in remodeling fibers during an early stage of peripheral nerve development. Thus, the morphological changes seen in the sciatic nerve of the NPC mouse may be an expression of perturbation in myelin maintenance as a result of defective cholesterol metabolism.

[Gene technology to overproduce the enzymes useful as diagnostic reagents]

We cloned the genes encoding the microbial enzymes described below and discussed the possibility as the diagnostic reagents: Creatinase(CR) and sarcosine oxidase(SOX) are useful for a diagnostic measurement of creatinine in combination with creatinase. Bacillus sp. B-0618 produces both CR and SOX enzymes when grown in the presence of an inducer, choline chloride. We cloned these two genes encoding CR and SOX by using recombinant DNA techniques. We found that the SOX-encoding gene is located upstream from the CR-encoding gene. When the CR- and SOX-encoding genes were independently inserted into the pUC-based vector and introduced into Escherichia coli, the transformants produced 15.5-fold more CR and 50-fold more SOX than Bacillus sp. B-0618, respectively, in the absence of the inducer. Although the Bacillus SOX is a flavoprotein, we created an FAD-free SOX by site-directed DNA mutagenesis. The mutant protein no longer expressed the SOX activity. Cholesterol esterase is useful for a diagnostic measurement of total cholesterol in combination with cholesterol oxidase. We cloned a gene encoding the cholesterol esterase enzyme. When the gene was introduced into the non-producing Streptomyces strain, the transformant produced the cholesterol esterase. Phospholipase A2 is a diverse family of enzymes that hydrolyze the sn-2 fatty acyl ester bond of phosphoglycerides producing free fatty acids and lysophospholipids. The enzymes are present in pancreatic juice and in the venoms of snakes and bees, where they serve digestive functions.(ABSTRACT TRUNCATED AT 250 WORDS)

Genomic organization and isoforms of the mouse ELP gene

Analysis was made on the genomic structure, functions, and expression of the mouse ELP gene, which codes for the embryonal long terminal repeat binding protein. Extensive screening of the cDNA library of embryonal carcinoma cells (EC cells) identified four isoforms of ELP: ELP1 (the original ELP isolate), ELP2, ELP3, and Ad4BP/SF1. Analysis of the genomic sequences revealed that these ELP isoforms were generated by alternative promoter usage and differential splicing. The mRNAs of isoforms initiated at four transcription start sites distributed on three exons. Sequence analysis of the four isoforms identified three polypeptides. The N-terminal portion of ELP1 and ELP2 was longer than ELP3, and Ad4BP/SF1 by 77 aa. The DNA-binding domain and region II were shared by all four isoforms. The C-terminal portion shared by ELP2, ELP3, and Ad4BP/SF1 was 131 aa in length, and that specific to ELP1 was 57 aa in length. The ELP3 and Ad4BP/SF1 isoforms were identical for the coding sequence, but the two differed at the 5' noncoding region. Region II and III domains of nuclear receptors were thought to be involved in ligand-binding and transcriptional activation. ELP1, which lacked region III, functioned as a repressor. The isoforms carrying intact region II and region III functioned as transactivators. Expression of the four isoforms was studied in mouse tissues and in tissue culture cells by quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) analysis. Complex patterns of expression of these isoforms were observed in various tissues. All four ELP isoforms were expressed only in EC cells.

Expression of calcitonin receptors on human myeloid leukemia cells

Certain osteoclastic markers (multinucleation and tartrate-resistant acid phosphatase) were induced in human leukemia HL-60 cells by treatment with 10(-7) M 1,25-dihydroxy-vitamin D3 [1,25(OH)2D3] for 10 days. However, no formation of pits on a bone substrate by vitamin-treated HL-60 cells was detected. Expression of calcitonin receptors (CTR), another osteoclastic marker, was examined by means of the reverse transcriptase polymerase chain reaction. The human CTR-cDNA (T47D isotype) was amplified from untreated HL-60 cells, but not from cells treated with 1,25(OH)2D3. The CTR mRNA disappeared within 24 h after the treatment. Thus, 1,25(OH)2D3-differentiated HL-60 cells failed to show two intrinsic characteristics of osteoclasts, pit formation on a bone substrate and expression of CTR. We then examined the expression of CTR on established human leukemia cell lines. The CTR mRNA was expressed in myeloblastic ML-1 and promyelocytic HL-60 leukemia cells but not in more mature macrophage-like cell lines, U-937 and THP-1 cells. Neither B cell leukemia BALL-1, T cell leukemia Jurkat, promegakaryoblastic leukemia Meg-J, nor cervix uteri carcinoma HeLa S3 cells amplified the CTR products. The cDNA of BIN67-isotype CTR, that has an additional 16-amino acid insert in the putative first intracellular loop of T47D-type CTR [Kuestner et al. (1994) Mol. Pharmacol. 46, 246-255], was amplified by neither strain tested. It was suggested that the T47D-type CTR is a novel differentiation antigen of immature myeloid lineage cells.

Apoptotic cell death triggered by nitric oxide in pancreatic beta-cells

Nitric oxide (NO) is believed to be an effector molecule that mediates interleukin (IL)-1 beta-induced destruction and dysfunction of pancreatic beta-cells. We have demonstrated that both exogenous NO and NO generated endogenously by IL-1 beta brought about apoptosis of isolated rat pancreatic islet cells as well as pancreatic beta-cell tumor-derived cell line HIT. This apoptosis was characterized by cleavage of DNA into nucleosomal fragments of 180-200 bp and morphologically by nuclear shrinkage, chromatic condensation, and apoptotic body formation. The IL-1 beta-induced internucleosomal DNA cleavage occurred in a time- and dose-dependent manner. Actinomycin D, cycloheximide, and nitric oxide synthase inhibitors inhibited the DNA cleavage, which was correlated with the amount of NO produced, indicating that NO produced by HIT cells themselves could mediate the apoptosis. Furthermore, in the presence of tumor necrosis factor (TNF)-alpha, large amounts of NO were produced by IL-1 beta and DNA cleavage occurred more noticeably, although TNF-alpha alone did not generate NO. Streptozotocin (STZ), a diabetogenic reagent containing a nitroso moiety, also released NO and induced internucleosomal DNA cleavage in HIT cells. These results suggest that NO-induced internucleosomal DNA cleavage is an important initial step in the destruction and dysfunction of pancreatic beta-cells induced by inflammatory stimulation or treatment with STZ.

Immunochemical detection of metallothionein in brain

Polyclonal and monoclonal antibodies have been used to determine the levels of metallothionein (MT) isoforms in the brain, its regions, and its cellular elements. MT is found abundantly in the astrocytes but not in the oligodendroglia or microglia. The induction of astrocytic metallothionein by cytokines suggests an important role for this protein in providing long-term protection against oxidative damage in tissue injury and inflammation.

Significance of myeloperoxidase in rapidly progressive glomerulonephritis

Antineutrophil cytoplasmic autoantibodies (ANCAs) are found in the sera of patients with systemic vasculitis and crescentic glomerulonephritis. We developed monoclonal antibodies against myeloperoxidase (MPO), which is a major perinuclear-ANCA antigen, and examined the presence of MPO in renal tissue from patients with rapidly progressive glomerulonephritis (RPGN) using these monoclonal antibodies. Myeloperoxidase was found in the glomeruli in four of five cases of perinuclear ANCA-positive RPGN, and the distribution pattern was different from that of immunoglobulin G. In perinuclear ANCA-negative crescentic glomerulonephritis, MPO also was detected in two of three cases. Myeloperoxidase was not detected in the capillary walls or mesangium in other nephropathies, such as minimal change disease, membranous nephropathy, and mesangial proliferative glomerulonephritis, or in normal controls. Myeloperoxidase activity was elevated and inversely correlated with the titer of MPO-ANCAs in the sera of perinuclear ANCA-associated RPGN. These data suggest that MPO plays an important role in the glomerular injury of RPGN.

Rapid detection of Mycobacterium tuberculosis in sputa by the amplification of IS6110

A polymerase chain reaction (PCR) assay for the rapid detection of Mycobacterium tuberculosis in sputum samples was studied. The target DNA was a 123-base pair (bp) fragment of IS6110, which was repeated in the M.tuberculosis genome and was specific for the M.tuberculosis complex. Glass beads (2mm diameter) and lysozyme were used to lyse the mycobacteria and DNA was extracted by the phenol-extraction method. The amplified PCR product was detected by examination of ethidium-bromide-stained agarose gel and by hybridization with an oligonucleotide alkali-phosphatase-labeled probe. A total of 70 samples were tested. PCR was positive in all 13 smear and culture-positive samples, in 5 of 8 smear-negative and culture-positive samples, and in 1 of 49 smear and culture negative samples. The overall sensitivity and specificity were 85.7% and 98%, respectively. Thus, IS6110 as a PCR target was found to be very useful for the rapid diagnosis of M.tuberculosis infection and start of anti-tuberculous chemotherapy.

[A case of integrative visual agnosia]

We report a 78-year-old right-handed man with integrative visual agnosia (Humphreys et al.) that was associated with bilateral medial occipito-temporal infarction. The patient showed superior altitudinal hemianopsia, alexia, prosopagnosia, cerebral achromatopsia, and object agnosia. Elementary perception and information processing supposed to be executed by the stream to the parietal lobe were intact, since he was able to perceive the position and speed of moving object (catching the flying ball). He could not categorize neither real objects nor line drawings by sight. However, copying and matching of them was accurate, suggesting that his agnosia was an associative type (Lissauer). Detailed neuropsychological examinations revealed that his agnosia was due to a disturbance in integrating local form features into a perceptual whole. In addition, this patient showed difficulty in retrieval of objects from memory. However, it is unlikely that this disturbance itself was a cause of this particular form of agnosia.

Effects of antioxidants on fiber mutagenesis

Recent studies from this laboratory have shown that asbestos fibers are mutagenic in cultured mammalian cells when assayed using a system that can detect multilocus deletions. Southern analysis of the induced mutants shows that the majority contain large deletions ranging in size from a few thousand to several million basepairs. In the present study, the effects of free radical scavenging enzymes on the cytotoxic and mutagenic potential of chrysotile fibers were examined using the human-hamster hybrid (AL) cells. Exponentially growing cells were treated with graded doses of fibers for a 24 h period either in the presence or absence of catalase, superoxide dismutase (SOD) or Tempol. Fiber-exposed cells were treated with the various enzymes either concurrently with the fiber or extended through the entire expression period. While the survival of AL cells treated with graded doses of chrysotile fibers with or without a concurrent treatment with SOD and catalase was not significantly different, the mutation yield at the S1 locus was significantly reduced in cells treated with these antioxidant enzymes. Furthermore, cells treated with the enzymes for a prolonged period were not better protected than those treated only during fiber treatment. The SOD mimic nitroxide, Tempol, had no effect on either the survival or mutagenic yield of chrysotile fibers. While SOD and catalase reduced the mutagenic potency of asbestos fibers in AL cells, they did not alter the molecular spectrum of fiber-induced mutagenesis. Our results indicate that antioxidant enzymes can protect cells against the genotoxic damages induced by chrysotile fibers, and are highly suggestive of the roles of oxyradicals in the fibrogenic and carcinogenic mechanisms of asbestos fibers.

Monocyte-derived cultured dendritic cells are susceptible to human immunodeficiency virus infection and transmit virus to resting T cells in the process of nominal antigen presentation

The susceptibility of monocyte-derived cultured dendritic cells (DCs) to human immunodeficiency virus (HIV) infection and their role in viral transmission in the immune response were studied in detail. We observed that highly purified cultured DCs were infected with the T-tropic Lai strain of HIV type 1 (HIV-1Lai) via the CD4 receptor, and this was followed by formation of the complete provirus as detected by PCR. HIV mRNAs were transcribed at only low levels, and virus production was undectable; however, the addition of the purified protein derivative antigen of tuberculin and of autologous resting T cells to HIV-1Lai-infected DCs but not to HIV-1Lai-infected macrophages led to massive HIV transmission and production. These data suggest that the interaction of infected DCs with T cells during the normal immune response could play an important role in the activation and expansion of HIV.

Chemoprevention by dietary dehydroepiandrosterone against promotion/progression phase of radiation-induced mammary tumorigenesis in rats

When pregnant rats received whole body irradiations with 260 cGy gamma-ray at day 20 of pregnancy, and were then implanted with a diethylstilbestrol (DES) pellet for an experimental period of 1 year under feeding of a control diet, a high incidence (96.2%) of mammary tumors was observed. Administration of dietary 0.6% dehydroepiandrosterone (DHEA) together with DES implantation significantly decreased the incidence (35.0%) of mammary tumors. The first appearance of palpable tumors in the DHEA-fed group was 4.5 months later than that in the control group. For clarification of the mechanism of the chemopreventive action, we measured hormone levels in the serum of DHEA-fed rats. In the DHEA diet rats, the concentration of estradiol-17 beta exceeded, by approximately 6-fold, that in the control rats, while the levels of progesterone and prolactin were decreased by 30 and 45%, respectively. Interestingly, DHEA feeding prevented DES-induced hypertrophy of pituitary glands and DES-induced high level of prolactin in pituitary glands detected by immunohistochemical studies, but stimulated the development of mammary glands more than that in control rats treated with DES alone. These findings suggest that DHEA has a potent preventive activity against the promotion/progression phase of radiation-induced mammary tumorigenesis. The mechanism of chemoprevention by change of endocrinological environment is discussed.

[Effect of dosing schedule on efficacy of corticosteroid inhalation in chronic asthma]

A randomized study was conducted for 4 weeks to evaluate the effect of twice daily inhalation of beclomethasone dipropionate (BDP) inhalation (group A) as compared to four times a day inhalation (group B) in chronic asthma. Patients were randomly allocated to receive BDP at a dosage of eight puffs twice daily (800 micrograms/day, group A) or four puffs four times daily (800 micrograms/day, group B). Forty four patients entered the study but eleven were excluded because of their insufficient records or unfitness to eligibility criteria. There was no significant difference in patients' characteristics such as types, and severity of diseases between the two groups. Daily keeping of symptom scores, twice daily measurement of morning and night peak expiratory flow (PEF) and checking of the drug consumption were performed throughout the study. There was no significant difference in the mean %PEF either at 2 and 4 weeks at the study between the two groups. Symptom scores, asthmatic scores, bronchial hyperresponsiveness, pulmonary function tests (FVC, FEV1, FEV1%) and serum cortisol levels also showed no significant difference between the two groups. These results indicate that twice daily inhalation of BDP (800 micrograms/day) for four weeks caused the same effects on the patients with chronic bronchial asthma as 4 times daily inhalation did. Therefore, twice daily inhalation therapy with BDP is recommended for chronic bronchial asthma patients.

[Efficacy of video thoracoscopic lung biopsy in diffuse lung diseases: comparison with open lung biopsy]

The efficacy and safety of video thoracoscopic lung biopsy (VTLB) and of open lung biopsy (OLB) were compared in patients with diffuse lung diseases. Thirty-three patients who had undergone VTLB were retrospectively studied and compared with 67 patients who had undergone OLB. There were no significant differences in age (52.8 +/- 10.9 vs 53.4 +/- 10.3), in the number of biopsies per patient (2.6 +/- 0.6 vs 2.7 +/- 0.6), or in the rate of diagnosis (94% vs 93%) between the two groups. However, the rate of diagnosis was low when the number of VTLB or OLB performed per patient was low. The patients undergoing VTLB had significantly shorter operative times (VTLB, 100.2 +/- 27.2 min. vs OLB, 119.8 +/- 42.6 min; p < 0.01) and less blood loss (VTLB, 4.7 +/- 14.6 ml vs OLB, 65.7 +/- 77.0 ml; p < 0.001). Complications occurred in 3 of the 33 who underwent VTLB, and in 18 of the 67 who underwent OLB. These results indicate that VTLB is an effective and safe alternative in the diagnosis of diffuse lung diseases.

Apoptotic cell death triggered by nitric oxide in pancreatic beta-cells

Nitric oxide (NO) is believed to be an effector molecule that mediates interleukin (IL)-1 beta-induced destruction and dysfunction of pancreatic beta-cells. We have demonstrated that both exogenous NO and NO generated endogenously by IL-1 beta brought about apoptosis of isolated rat pancreatic islet cells as well as pancreatic beta-cell tumor-derived cell line HIT. This apoptosis was characterized by cleavage of DNA into nucleosomal fragments of 180-200 bp and morphologically by nuclear shrinkage, chromatic condensation, and apoptotic body formation. The IL-1 beta-induced internucleosomal DNA cleavage occurred in a time- and dose-dependent manner. Actinomycin D, cycloheximide, and nitric oxide synthase inhibitors inhibited the DNA cleavage, which was correlated with the amount of NO produced, indicating that NO produced by HIT cells themselves could mediate the apoptosis. Furthermore, in the presence of tumor necrosis factor (TNF)-alpha, large amounts of NO were produced by IL-1 beta and DNA cleavage occurred more noticeably, although TNF-alpha alone did not generate NO. Streptozotocin (STZ), a diabetogenic reagent containing a nitroso moiety, also released NO and induced internucleosomal DNA cleavage in HIT cells. These results suggest that NO-induced internucleosomal DNA cleavage is an important initial step in the destruction and dysfunction of pancreatic beta-cells induced by inflammatory stimulation or treatment with STZ.