Effects of one-lung ventilation on cardiac autonomic nervous activity as evaluated by power spectral analysis of heart rate variability

The purpose of this prospective study was to evaluate the effects of one-lung ventilation on the activity of the cardiac autonomic nervous system. Ten adult patients who underwent thoracotomy were endotracheally intubated with a double-lumen tube under general anesthesia using isoflurane. After induction of anesthesia, a continuous, 256-sec electrocardiogram (ECG) was obtained during bilateral lung ventilation (control) followed by recordings during one-lung ventilation of each side. Using the R-R interval tachograms obtained for the 256-sec ECGs, low frequency (LF: 0.04-0.15 Hz) and high frequency (HF: 0.15-0.40 Hz) bands of the spectral density of the heart rate variability and the HF/LF ratio were analyzed using the fast Fourier transform algorithm. Log(HF), which indicates parasympathetic activity, increased during one-lung ventilation on each side, but did not differ between ventilated sides. Log(LF), which represents sympathetic and parasympathetic activity, increased similarly to log(HF) on both sides. Log(HF/LF), the balance of the sympathetic and parasympathetic activity, did not change during one-lung ventilation. We suggest that one-lung ventilation alone does not substantially affect the cardiac autonomic nervous system.

Aging and salt-loading modulate blood pressure QTLs in rats

To evaluate the effects of nongenetic factors, aging, and salt-loading on the quantitative trait loci (QTLs) for blood pressure (BP), we conducted a genome-wide linkage analysis using multiple sets of BP measurements in 125 male F2 generation cross derived from stroke-prone spontaneously hypertensive rats and normotensive Wistar-Kyoto rats. The experiment was arranged in two stages. In the first stage, corresponding to the developing period of the rats, BP was measured repeatedly without loading of salt; this continued until the rats were 5 months of age. In the second stage, after the baseline BP leveled off, 1% salt water was given to the rats and BP was monitored for the subsequent 7 months. Genome scanning was performed using 201 markers. In the developing period, three QTLs were identified on chromosomes 1, 3, and 4 (logarithmic odds [LOD] scores of 5.6, 3.1, and 3.2, respectively), which had peaks at 8 or 10 weeks of age. In the latter salt-loading stage, QTLs for BP were detected on chromosomes 1 and 10 (LOD scores 4.6 and 4.5, respectively). When the BP increase during salt-loading was analyzed as a phenotype, however, only the region on chromosome 10 showed linkage at a suggestive level (LOD score 3.2). The present study provides experimental evidence that QTLs for BP could be modulated by nongenetic factors, such as aging and salt-loading.

Analysis in spontaneously hypertensive rats

1. Linkage analysis is performed between basal or salt-sensitive high blood pressure and several loci on chromosomes in F2 progenies obtained from crossing stroke-prone spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto rats. 2. Basal hypertensive genes are mapped to a region near the D1Mit2 locus on chromosome 1 and near the D3Mgh8 locus on chromosome 3 in the male and female F2 progenies. 3. Salt-sensitive hypertensive gene is mapped to a region near RR1023 locus on chromosome 10 in the male F2 progenies. 4. Salt-sensitive hypertensive gene is mapped to a region near D3Mgh12 locus on chromosome 3 in the female F2 progenies.

Identification of Vibrio parahaemolyticus strains at the species level by PCR targeted to the toxR gene

The DNA colony hybridization test with the polynucleotide probe for Vibrio parahaemolyticus toxR gene was performed. All 373 strains of V. parahaemolyticus gave positive results, and the strains belonging to four other Vibrio species including Vibrio alginolyticus gave weakly positive results, suggesting that toxR sequence variation may reflect the phylogenetic relationships of Vibrio species. We then established a toxR-targeted PCR protocol for the specific detection of V. parahaemolyticus.

Activation of monocytes in vivo causes intracellular accumulation of lipoprotein-derived lipids and marked hypocholesterolemia--a possible pathogenesis of necrobiotic xanthogranuloma

Necrobiotic xanthogranuloma (NXG) is a rare histiocytic disease with generalized xanthomatosis. However, most cases with NXG are normolipidemic or hypolipidemic. The mechanism for the formation of xanthoma in NXG has not yet been clarified. We observed a case of NXG with severe hypocholesterolemia (total cholesterol: 1.69 mmol/l) and analyzed the function of monocytes in this case. Histological examinations by light microscopy revealed a large amount of lipid deposition in the patient's freshly isolated monocytes. The patient's monocytes showed a 3-fold increase in cholesteryl ester content and a 3-fold enhancement of acetyl low density lipoprotein (LDL) uptake compared with the control monocytes. However, no significant difference was noted in the expression of CD36 protein and the mRNA levels of scavenger receptor-class A (SR-A) between the monocytes of the patient and the control. The phagocytotic ability of the patient's monocytes was enhanced 1.5-fold compared with that of the control monocytes. These findings suggest that the activated monocytes may have degraded the modified LDL via a pathway other than CD36 or SR-A, and accumulated a great amount of lipids in vivo. In conclusion, the present study has demonstrated a possible pathogenesis of NXG that the activation of monocytes in vivo may contribute to the intracellular accumulation of lipoprotein-derived lipids leading to non-inherited xanthomatosis and the marked hypocholesterolemia.

Isolation of an Escherichia coli O157:H7 strain producing Shiga toxin 1 but not Shiga toxin 2 from a patient with hemolytic uremic syndrome in Korea

Escherichia coli strains isolated from patients with diarrhea or hemolytic uremic syndrome (HUS) at Pusan University Hospital, South Korea, between 1990 and 1996 were examined for traits of the O157:H7 serogroup. One strain isolated from a patient with HUS belonged to the O157:H7 serotype, possessed a 60-MDa plasmid, the eae gene, and ability to produce Shiga toxin 1 but not Shiga toxin 2. Arbitrarily primed PCR analysis suggested that this strain is genetically very close to a O157:H7 strain isolated in Japan.

Surface composition regulates clearance from plasma and triolein lipolysis of lipid emulsions

Sphingomyelin (SM) and cholesterol (Chol) are major surface lipid constituents of plasma lipoproteins. We investigated the effects of SM and Chol on the plasma clearance of lipid emulsions as a model for lipoprotein particles in rats. The presence of Chol facilitated the removal of emulsion particles from plasma, whereas SM delayed particle removal. Preinjection of lactoferrin, an inhibitor of the apolipoprotein E (apoE) receptor, revealed that the differences in clearance of emulsions were due to the differences in affinity for the apoE receptor. Measurement of apolipoprotein binding suggested that the balance of apoE and apoC (apoC-II and apoC-III) bound to emulsions caused the difference in plasma clearance of emulsion particles. That is to say, SM in the emulsion surface decreased binding of apoE, which led to a longer circulation of emulsion particles in plasma. Chol, on the other hand, decreased the ratio of apoC to apoE, which may have promoted emulsion uptake through the apoE receptor. We also examined in vitro lipolysis using immobilized lipoprotein lipase (LPL) in a heparin affinity column. Lipolysis rates were significantly reduced by the incorporation of SM into the emulsion surface, but not by the incorporation of Chol, indicating that SM in the lipoprotein surface is an important lipid component regulating LPL-mediated lipolysis. Our results suggest that the presence of SM and Chol in the lipoprotein surface plays an important role in the circulation behavior and LPL-mediated lipolysis of lipid emulsions through their effect on the selectivity of plasma protein binding.

Construction of a rat genetic map by using randomly amplified microsatellite polymorphism (RAMP) markers

Many rat strains have been employed in the genetic study of quantitative traits such as blood pressure. In such genetic studies, it is essential to prepare rat genetic maps fine enough to identify the genes regulating quantitative traits. However, it is not an easy task to isolate a sufficient number of genetic markers polymorphic between a particular pair of rat strains. In this study, we applied the randomly amplified microsatellite polymorphism (RAMP) method, a simple method to identify co-dominant markers (Wu et al. Nucleic Acids Res 22, 3257, 1994), to isolate markers polymorphic between the stroke-prone spontaneously hypertensive rat and the Wistar-Kyoto rat, a genetically hypertensive strain and its normotensive control strain, which share a common genetic background. We successfully identified 111 RAMP markers distributed throughout the rat genome after screening 3046 sets of primers. We also showed that we could isolate ordinary simple-sequence-length-polymorphism markers by cloning RAMP markers. The RAMP method is a simple and efficient way to identify co-dominant genetic markers on mammalian genomes.

Detection and quantitation of HBV DNA by semi-nested PCR in donated blood: comparison with HBV serological markers

To detect and quantitate hepatitis B virus (HBV) DNA, semi-nested polymerase chain reaction (PCR) method was designed for amplifying the HBV core region DNA. Cloned HBV core region DNA was used as a quantitation control, and upon electrophoresis of the semi-nested PCR product, one, two, or three bands of amplified DNA were observed using a small (< 50 mol), moderate (around 200 mol), or large (> or = 1250 mol) quantity of the template DNA, respectively. Using this semi-nested PCR method, HBV DNA was quantitated in donated blood and tested for HBV serological markers. Most of the HBV surface antigen (HBsAg) high titer samples showed three bands on the electrophoresis, indicating a high level of HBV DNA, while most of the HBsAg low titer samples showed one band, indicating a low level of HBV DNA. HBV DNA was detected in 7 out of 36 HBsAg-undetectable and anti-HBc-positive samples (19.4%) but all 7 showed one band, indicating a low level of HBV DNA. In almost all of the HBV e antigen-positive samples the HBsAg titer was high, and three bands were observed indicating a high level of HBV DNA.

Virulent and avirulent Rhodococcus equi infection in T-cell deficient athymic nude mice: pathologic, bacteriologic and immunologic responses

We investigated the pathologic, bacteriologic and immunologic responses of BALB/c-nu/nu mice (nude mice) and BALB/c mice (euthymic mice) infected intravenously with virulent and avirulent Rhodococcus equi ATCC 33701, and its plasmid-cured derivative ATCC 33701P-, to evaluate the role of T lymphocytes. Adaptive transfer of immune and normal spleen cells into nude mice was also investigated. Nude and euthymic mice were inoculated with 10(6) ATCC 33701 or 10(6) ATCC 33701P- intravenously (i.v.) and killed at 0, 7, 14, 21, 28 and 35 days post-inoculation, except dead cases. In athymic nude mice infected with ATCC 33701, deteriorating systemic inflammatory responses developed during the experimental period and multiplication of the bacteria continued until the end of the experiment. Nude mice developed splenomegaly and multifocal gross hepatic necrosis with some mortality. Splenomegaly was caused by diffuse proliferation of bacteria-laden macrophages and epithelioid cells, and gross hepatic necrosis was caused by the formation of thromboses and granulomatous lesions. Infection of euthymic mice with a sublethal dose of ATCC 33701 resulted in transient granuloma formation in the liver and spleen, production of specific antibodies against the virulent bacteria and gradual elimination thereof. In contrast, infection with ATCC 33701P- produced few lesions after rapid elimination and no antibody production against bacteria in either normal or athymic nude mice. In nude mice given normal and immune spleen cells, histopathological lesions and granulomas formed only in the liver and spleen, in addition to specific antibodies against 15- to 17-kDa antigens. The pathological lesions observed in the nude mice given immune spleen cells were similar to those seen in the mice given normal spleen cells, but they were less severe than those in mice given normal spleen cells. Mice given immune spleen cells showed a significantly higher elevation of antibody production than mice given normal spleen cells. These results suggested that protection against virulent R. equi in mice depends mainly on cell-mediated immune responses, whereas avirulent R. equi in mice are cleared by innate immune responses.

Cosegregation of the new region on chromosome 3 with salt-induced hypertension in female F2 progeny from stroke-prone spontaneously hypertensive and Wistar-Kyoto rats

1. We investigated candidate loci for salt-sensitive high blood pressure (BP) in F2 progeny from crossing Wistar-Kyoto and stroke-prone spontaneously hypertensive rats. 2. In female F2 progeny, systolic and diastolic BP on the 12th day and the seventh month after salt loading was strongly linked with the D3Mgh12 and D3Mgh6 loci on chromosome 3, respectively. 3. These loci were linked with BP only in female F2 progeny, not in males. 4. These results indicate that hormonal factors may influence salt sensitivity, particularly with respect to gender differences.

Atropine premedication attenuates heart rate variability during high thoracic epidural anesthesia

BACKGROUND

Atropine premedication is used as it possesses an anticholinergic effect on the cardiac autonomic nervous system (CANS). The aim of this study was to investigate the effect of atropine premedication on the CANS during thoracic epidural anesthesia (TEA) by assessing power spectral analysis of heart rate (HR) variability.

METHOD

Female patients (n = 28) undergoing elective mammary biopsy were randomly allocated into two groups; one received intramuscular premedication of 0.01 mg/kg of atropine 30 min before the procedure (group A: n = 14), and the other did not (group N: n = 14). Each electrocardiogram was digitally recorded before and during TEA, and played back off-line to detect R-R intervals. As a power spectrum required R-R intervals of 256 s, this was analysed before TEA and repeated thereafter for 25 min. The spectra were quantified by determining the peak areas of the spectral density by integrating low frequency (Lo: 0.04-0.15 Hz) and high frequency (Hi: 0.15-0.40 Hz) bands as they showed sympathetic and parasympathetic nervous activity in the CANS. The neural balance was assessed by calculating Hi:Lo ratio.

RESULTS

Decreases in Lo and increases in Hi:Lo ratio were observed, suggesting sympathectomy and vagotonia with TEA in both groups. For 10 min after commencement, TEA maintained Hi:Lo ratios lower in group A than in group N, suggesting a vagolytic effect of premedication with atropine. With TEA, cardiac slowing was observed, which was dependent on the level of dermal analgesia.

CONCLUSION

Power spectral analysis revealed that TEA had the effect of making CANS relatively vagotonic, and that atropine premedication would attenuate the effect of TEA.

Trisomy 16 mosaicism in amniotic fluid cell cultures

Trisomy 16 mosaicism was found in amniotic fluid cells in a patient undergoing amniocentesis because of elevated second-trimester maternal serum alpha-fetoprotein (MSAFP) (2.80 MOM), a markedly elevated human chorionic gonadotropin level (hCG) (12.02 MOM), and a Down syndrome risk of 1:55. Ultrasound evaluation of the fetus indicated the presence of an atrial septal defect and clinodactyly. Cytogenetic analyses of various fetal tissues using fluorescence in situ hybridization (FISH) failed to detect substantial numbers of trisomy 16 cells; however, trisomy 16 mosaicism was identified in placental tissue. Molecular genetic analysis at five different loci [four analysed by polymerase chain reaction (PCR) and one by Southern blot analysis] failed to show any evidence for uniparental disomy. Although trisomy 16 cells could not be clearly demonstrated in the fetus, the presence of a clinically significant proportion of aneuploid cells early in development could not be excluded and it therefore cannot be assumed that a 'confined placental mosaicism' existed. The markedly elevated hCG and elevated MSAFP levels are consistent with abnormal placental function in trisomy 16 mosaicism. Serial ultrasound evaluation (to detect any late-onset growth retardation) and fetal echocardiography may be indicated for patients with extraordinarily high levels of hCG, especially if MSAFP is also elevated.

Immunohistochemical demonstration of S-phase cells by anti-bromodeoxyuridine monoclonal antibody in cattle tissues

Bromodeoxyuridine (BrdU), a non-radioactive thymidine analogue, was administered to 15 cattle at a dosage of 1-10 mg/kg intravenously or intraperitoneally to demonstrate S-phase cells in the tissues. The organs and tissues were fixed in 10% neutral buffered formalin or in 70% ethanol, sectioned, denatured with hydrochloric acid, and treated with monoclonal antibody against BrdU. Immunohistochemical methods were used to "visualize" BrdU-labelled nuclei. BrdU-positive cells were satisfactorily demonstrated in both formalin- and ethanol-fixed tissues of animals given doses of 2 mg/kg or over, by either route of administration. Large numbers of BrdU-positive cells indicative of active cell production were found in the basal region of the stratified squamous epithelium, the neck between gastric pits and gastric glands in the abomasum, and the crypts of Lieberkühn of the small and large intestines. Moderate numbers of positive cells were observed amongst inflammatory cells in cases of nephritis and in granulation tissue. Numerous positive cells were detected in leukaemia cells. The study showed that BrdU can be used to measure proliferative S-phase cells in cattle, as in human beings, mice and rats.

A new locus on chromosome 3 strongly linked with salt-sensitive high blood pressure in female F2 from SHRSP and WKY rats

1. We investigated candidate loci for salt-sensitive high blood pressure in F2 progeny from crossing Wistar-Kyoto rats and stroke-prone spontaneously hypertensive rats. 2. The average systolic and diastolic blood pressure did not increase in male and female F2 progeny by the 12th day after salt loading. 3. In female F2 progeny, systolic and diastolic blood pressure became strongly linked with the MITR244 locus on chromosome 3, 1 month and 12 days after salt loading. 4. This locus became linked with blood pressure only in the female F2 progeny and not in the males. 5. These results indicate that hormonal factors and gender differences, in particular, might influence salt sensitivity.

In search of genes causing spontaneous hypertension

1. Basal high blood pressure (BP) in the male and female F2 progeny produced by crosses between Wistar Kyoto rats (WKY/lzm) and stroke-prone spontaneously hypertensive rats (SHRSP/lzm) linked strongly with the leukosialin locus on chromosome 1. 2. Excess salt intake caused elevation of BP and the response was larger in the females than the males. 3. In the male F2 progeny, salt-sensitive hypertension significantly cosegregated with the RR1023 marker on chromosome 10, rather than with the angiotensin converting enzyme locus. 4. In the female F2 progeny, salt-sensitive hypertension significantly linked with the MitR244 marker on chromosome 3.

Ca(2+)-activated outward-rectifier K+ channels and histamine release by rat gastric enterochromaffin-like cells

Gastric enterochromaffin-like (ECL) cells were isolated from rat gastric fundic mucosa by Percoll density-gradient centrifugation and counter-flow elutriation. About 67% of cells in the purified cell suspension were ECL cells, which were reacted with anti-histidine decarboxylase antibody. A23187, a calcium ionophore, at 0.1-10 microM induced histamine release from ECL cell-rich suspension, indicating that the Ca2+ pathway is involved in the mechanism of histamine release from the ECL cells. A23187 at 5 microM significantly increased outward-rectifier cationic current in 62% of cells in the ECL cell-rich factions. A23187-sensitive cells showed acridine orange uptake. In single-channel recordings, a Ca(2+)-dependent outward-rectifier K+ channel of large conductance (146 +/- 22 picosiemens) was found in the cell that showed acridine orange uptake. The channel opened in a voltage-dependent manner at 0.1 microM of intracellular free Ca2+ concentration. These results may suggest that opening of the Ca(2+)-activated K+ channel is one of the steps involved in the mechanism of histamine release in ECL cells.

Pathogenesis of Rhodococcus equi infection in mice: roles of virulence plasmids and granulomagenic activity of bacteria

Virulence of Rhocococcus equi ATCC 33701 and its plasmid-cured derivative ATCC 33701P- was compared in BALB/c and C3H/HeJ mice in terms of bacterial growth kinetics and histological changes in the liver, spleen and lungs, and humoral immune responses. Injection with a sublethal dose of 10(6) ATCC 33701 in mice resulted in microabscess formation after rapid multiplication in the liver and spleen by day 4, and then the bacteria were gradually eliminated with the formation of granuloma and the production of specific antibodies against 15- to 17-kDa antigens of the virulent bacteria. By contrast, ATCC 33701P- was avirulent as shown by early elimination of viable bacteria and no evidence of net multiplication in the organs. Histopathological changes consisted of only slight, transient infiltration of neutrophils and macrophages in the liver. Although live ATCC 33701P- did not evoke any humoral or histological responses in the mice, a large inoculum (10(8)) of killed ATCC 33701 and ATCC 33701P- resulted in the formation of granuloma in the liver and accelerated extramedullary hemopoiesis in the spleen. These results suggest that the pathogenesis of R. equi infection involves at least two important virulence determinants, both of which play critical roles in the disease: one is the virulence plasmid, which is required for R. equi to resist and grow within host cells; and the other is the granulomagenic activity that is related to the lipids and nature of the cell wall of the species, which induces the characteristic pathological changes.

Incidence, source, and nature of complaints received in a large, urban emergency medical services system

OBJECTIVE

To document the incidence, source, and reasons for all complaints received by a large municipal emergency medical services (EMS) program.

METHODS

A retrospective review of all complaints received during three consecutive years (1990-1992) in a centralized EMS system serving a large municipality (population 2 million). All cases were categorized by year, source, and nature of the complaint.

RESULTS

In the three study years, EMS responded to 416,892 incidents with nearly a half-million patient contacts. Concurrently, 371 complaints were received (incidence of 1.12 per thousand); 132 in 1990, 129 in 1991, and 110 in 1992. Most complaints involved either: 1) allegations of "rude or unprofessional conduct" (34%), 2) "didn't take patient to the hospital" (19%), or 3) "problems with medical treatment" (13%). Only 1.6% (n = 6) were response-time complaints. Other complaints included "lost/damaged property," "taken to the wrong hospital," "inappropriate billing," and "poor driving habits." The most common sources were patient's families (39%) and the patients themselves (30%). Only 7.8% were from health care providers.

CONCLUSION

Reviews of complaints provide information regarding EMS system performance and reveal targets for quality improvement. For the EMS system examined, this study suggests a future training focus on interpersonal skills and heightened sensitivities, not only toward patients, but also toward bystanders and family members.

Possible involvement of androgen in increased norepinephrine synthesis in blood vessels of spontaneously hypertensive rats

We investigated the effects of castration and testosterone propionate on sympathetic nervous systems in spontaneously hypertensive rats (SHR) and Wistar Kyoto rats (WKY). Four-week-old male rats were castrated. For replacement of androgen, testosterone propionate (500 micrograms/rat) was administered subcutaneously 2 times a week to castrated rats after their 14th week. The systolic blood pressure of the castrated SHR (44 weeks) was significantly lower than those of intact SHR and testosterone-replaced SHR. The norepinephrine (NE) levels and the tyrosine hydroxylase (TH) activities in the abdominal aorta and mesenteric artery of castrated SHR (45-50 weeks) were significantly lower than those of intact SHR. The NE levels and the TH activities in these blood vessels of testosterone-replaced SHR recovered to the levels obtained in those of intact SHR. As well as the systolic blood pressure, the NE levels and TH activities in blood vessels of WKY were significantly lower than those of intact SHR and showed no significant difference among the three groups. These results suggest that androgen may contribute to the development of hypertension in SHR via sustained enhancement of TH activity in blood vessels leading to increased NE level.

A 3-basepair in-frame deletion (delta Leu999) in exon 17 of the insulin receptor gene in a family with insulin resistance

We studied a woman with acanthosis nigricans and insulin resistance. The patient's Epstein-Barr virus-transformed lymphocytes revealed slightly decreased insulin binding and markedly decreased insulin-stimulated autophosphorylation of the insulin receptor. The nucleotide sequence analysis of the patient's genomic DNA revealed a 3-basepair in-frame deletion in one allele, resulting in the loss of leucine at position 999 of the insulin receptor (delta Leu999). The messenger ribonucleic acid transcripts from the mutant allele in the patient's lymphocytes were not decreased. Insulin-stimulated autophosphorylation of the insulin receptor from cells expressing delta Leu999 mutant insulin receptor complementary DNA was markedly decreased. The proband, her mother, elder brother, and younger brother, who were heterozygous for this mutation, showed moderate or marked hyperinsulinemia during oral glucose tolerance tests. Although fasting glucose levels were normal and fasting insulin values were preserved in all subjects with the mutation for the 8-yr period of observation, a tendency of progressive increase in postload glucose levels was observed. These results suggest that the delta Leu999 mutation, which reduces tyrosine kinase activity, was responsible for insulin resistance and contributed to postload hyperglycemia.

HLA class II alleles in Japanese patients with Graves' disease: weak associations of HLA-DR and -DQ

To elucidate the associations of the HLA class II alleles with Graves' disease (GD), we examined DRB1, DQA1, DQB1 alleles in 62 Japanese GD patients and 142 control subjects by the PCR-SSOP (polymerase chain reaction-sequence specific oligonucleotide probes) method. We found that DRB1*0803 (P < 0.02), DRB1*1403 (P < 0.03), DQA1*0103 (P < 0.02) alleles and DRB1*0803-DQA1*0103-DQB1*0601 (P < 0.01), DRB1*1403-DQA1*0501-DQB1*0301 (P < 0.02) haplotypes were significantly increased in GD patients. No DQB1 allele revealed a significant association with GD in Japanese. These weak associations may reflect either the heterogeneity of GD in Japanese or the importance of non-HLA factors in the development of the disease.

Association of polymorphism in the interferon gamma gene with IDDM

Cytokines may play important roles in the pathogenesis of insulin-dependent diabetes mellitus (IDDM). We analysed a dinucleotide repeat polymorphism within the first intron of the interferon gamma (IFN-gamma) gene in Japanese diabetic patients (175 IDDM and 145 non-insulin-dependent diabetes mellitus) and 267 control subjects. A significant difference was observed in the global allele distribution of the polymorphism between the IDDM and control groups (p = 0.039). The difference from the control group was more evident in the patients whose insulin therapy started within 1 year from onset (p = 0.006) or in the young-onset (< 10 years) patients (p = 0.0006). The alleles "3" and "6" were increased in the IDDM patients, and a significant increase in the frequency of the "3/6" genotype was observed in the IDDM patient group (9.1%, RR 2.9, p = 0.010), in the patients with initial insulin therapy less than 1 year from onset (10.6%, RR 3.4, p = 0.004), or in the young-onset patients (16.7%, RR 5.7, p = 0.0003) in comparison to the control subjects (3.4%). There was a tendency towards frequent occurrence of clinical characteristics which reflect young or abrupt onset of diabetes or both, and depletion of insulin secretion capacity in the patients with "3/6" or "6/6" in comparison to the patients with other genotypes. These results suggest that the IFN-gamma gene region may contribute to the pathogenesis of IDDM and could be a genetic marker for IDDM.