[Validity of urinary glucose test for diabetes screening in workplace regular medical checkups]

It has been acknowledged that urinary glucose level varies depending on the time after meal which may hence affect validity of urinary glucose test as a screening test for diabetes. However, sample collection time has not been standardized for urinary glucose test in workplace regular medical checkups. In this study, we investigated the effect of timing of urine sampling on results of urinary glucose screening tests, and using data obtained from the 75 g oral glucose tolerance tests (OGTT) evaluated the validity of urinary glucose test in workplace medical checkups. Also, we made a survey among industrial physicians about the timing of sample collection. Between 1991 and 1996, 455 males and 116 females who participated in a 2-day health examination including the OGTT in a hospital in Chiba were used as study subjects. These did not include an additional 22 subjects who had already been diagnosed as having diabetes but received the OGTT. The examinees observed a strict fast after supper the previous evening and urine and blood samples were collected before and 2 hours after glucose intake for the OGTT. Diagnosis of diabetes was made following the criteria of WHO (1985) and screening test results were defined positive when urinary glucose level was equal to or more than 40 mg/dl. Sensitivity and specificity were calculated for diabetes and impaired glucose tolerance separately for male and female. Industrial physicians who participated in a lecture course for qualification were surveyed about the timing of urine sample collection for urinary glucose test in workplace regular medical checkups. For the urine samples collected 2 hours after glucose intake, sensitivity was very high (male 84%, female 100%), in addition to a relatively high specificity (male 71%, female 92%). However the samples collected before glucose intake showed extremely poor sensitivity (male 11%, female 0%). Similar results were obtained when screening was made for impaired glucose tolerance and both diabetes and impaired glucose tolerance combined. The survey among the industrial physician revealed that in the majority (58%) of workplace medical checkups, the urine sample had been collected when examinees were fasting. The largest reason for this was that the urinary glucose test was performed together with upper gastro-intestinal examination or measurement of serum triglyceride both of which require fasting of examinees. The results of the present study showed that urinary glucose tests have been frequently performed at a timing that produces low validity. The procedures of workplace regular medical checkups should be evaluated with the concept of Evidence Based Medicine. The standard of the timing of urine sample collection for urinary glucose test should be carefully examined.

[Prevalence of dental erosion caused by sulfuric acid fumes in a smelter in Japan]

The effect of occupational sulfuric acid exposure and other factors on teeth was explored in a cross-sectional study with blind dental examinations. Among 350 male workers in a copper-smelter in Japan, 28 had mild dental erosion with silky-glazed opaque appearance of the enamel and/or shallow concavities on the enamel. While opaqueness was observed in 20 and concavities found in 11 workers, only 3 had both signs, suggesting that the concave lesions were often accompanied with enough remineralization to keep the dental surface gloss, possibly due to acid exposure at a low level. The cases had a history of working in an electrolytic refining plant (36%), significantly more than in the non-cases (14%, p < 0.05). Some significant differences were found between the cases and the non-cases: the cases were older, had less dental plaque, less gingivitis, and more frequent toothbrushing habits. No significant differences were observed in possibly related dietary habits such as several types of acidic drinks. It was concluded that the present cases with dental erosion were most probably associated with occupational acid exposure. The risk ratio of cross-sectional prevalence of dental erosion for those with a history of electrolytic refining plant work was 3.0 (95% CI: 1.3-6.7) compared with those without a history of acid exposure. Whether the present work environment can still develop new cases of dental erosion remains to be studied.

FDG-PET in differential diagnosis and grading of chondrosarcomas

PURPOSE

The purpose of this work was to investigate the usefulness of PET with [18F]2-deoxy-2-fluoro-D-glucose (FDG) in the differential diagnosis and grading of chondrosarcomas.

METHOD

Four enchondromas, one osteochondroma, and six chondrosarcomas were prospectively studied by FDG-PET. The significance of the standardized uptake value (SUV) was evaluated in comparison with clinical, radiological, and histopathological findings of the tumors.

RESULTS

The SUV ranged from 0.7 to 1.3 (mean 0.96+/-0.22) in benign cartilage tumors and from 1.3 to 3.3 (2.23+/-0.80) in chondrosarcomas. This SUV difference between benign and malignant tumors was statistically significant (p = 0.011) in contrast to considerable overlap of clinical and radiological findings. Among chondrosarcomas, the SUV of one Grade I tumor was 1.3; those of four Grade II tumors were 1.3, 1.9, 2.5, and 3.1; and that of one Grade III tumor was 3.3.

CONCLUSION

Our preliminary study showed that FDG-PET could be an objective and quantitative adjunct in the differential diagnosis and grading of chondrosarcomas.

Intrahepatic cholangiocarcinoma with extensive sarcomatous change: report of a case

A 77-year-old woman was admitted to our hospital with severe upper abdominal pain. Ultrasonography showed a well-defined hypoechoic mass with heterogeneity in the left lobe of the liver, and computed tomography demonstrated a low-density mass with enhanced peripheral areas. Magnetic resonance imaging revealed a mass with iso- to low signal intensity on T1-weighted images (WI) and heterogeneous high and low signal intensity on T2 WI. The tumor was found to be hypovascular by angiography. During 5 months of observation, the tumor increased in size, which strongly suggested malignancy. A laparotomy was performed under the provisional diagnosis of a neoplasm other than hepatocellular carcinoma, revealing that the hepatic mass had invaded the gastric wall. Therefore, a left hepatic lobectomy with dissection of the lymph nodes and hemigastrectomy was carried out. Histologically, the tumor was found to be composed of a large amount of sarcomatous elements and a small amount of adenocarcinomatous elements, both of which were partly intermingled. Immunohistochemically, the sarcomatous element demonstrated the features of malignant fibrous histiocytoma (MFH). Thus, a diagnosis of intrahepatic cholangiocarcinoma with MFH-like sarcomatous change was confirmed.

Manifestation of pulmonary hypertension during REM sleep in obstructive sleep apnea syndrome

The effect of sleep stage change on pulmonary circulation has not been well documented in patients with obstructive sleep apnea syndrome (OSAS). We investigated whether or not stage-specific change can affect pulmonary artery pressure (Ppa) in patients with OSAS. Thirty-one patients with OSAS underwent right cardiac catheterization in the daytime and the following night, including 19 patients in whom Ppa could be measured throughout non-rapid eye movement (NREM) and rapid eye movement (REM) sleep. Ten of the 19 patients had daytime pulmonary hypertension (PH) defined by a mean Ppa (Ppa) >/= 20 mm Hg. Then we analyzed Ppa response to hypoxia spontaneously occurring during the period of sleep apnea. The slopes of the regression lines between arterial oxygen saturation measured by pulse oximeter (SpO2) and Ppa curves were almost the same in both NREM and REM patient groups with or without daytime PH, whereas the response curve was significantly shifted upward in REM compared with NREM patients with daytime PH. Furthermore, Ppa was elevated more markedly in association with REM burst, phasic REM, compared with tonic REM. We conclude that vascular tone of pulmonary artery could be elevated in association with REM sleep which is independent of the degree of hypoxia, and that this state-specific change is manifested in patients with daytime PH.

Impact of shift work on cardiovascular functions in a 10-year follow-up study

OBJECTIVES

The purpose of this study was to determine whether shift work affects the heart-rate-adjusted QT interval (QTc) in electorcardiography (ECG) and the blood pressure of workers without overt cardiovascular dysfunction.

METHODS

At a copper smelter, 158 shift workers and 75 day workers who underwent an ECG examination and blood pressure measurements in 1986 were followed for 10 years. In 1996, biochemical indicators such as high-density lipoprotein cholesterol and triglycerides were measured, together with the QTc.

RESULTS

In 1986 and 1996, the QTc was significantly longer in the shift workers than in the day workers. Of 180 workers with a normal QTc (<420 ms(1/2) in 1986, 15% had developed a prolonged QTc (420 ms(1/2) in 1996 (18% of the 117 shift workers and 11% of the 63 day workers). Among the workers with a normal QTc in 1986, the shift workers had a significantly longer QTc than the day workers when the QTc was examined in 1996. In addition, shift-day work in the group with a normal QTc was significantly related to the QTc in 1996 after control for age, work duration, biochemical indicators, smoking, and drinking habits. However, the blood pressures of the shift and day workers did not differ significantly, and in 1996 the values of both groups were significantly elevated.

CONCLUSIONS

These data suggest that shift work is associated with QTc prolongation. This evidence may explain the increased risk for cardiovascular diseases due to shift work.

[Antibody prevalence against astrovirus according to age groups]

A study on the prevalence of antibodies against human astrovirus serotype 1 (HAstV-1) and 2 (HAstV-2) was carried out in 170 serum samples obtained from different age groups in Tokyo and Saitama, Japan. Prevalence of specific IgG antibodies to both HAstVs showed decreasing tendency after birth and reached a minimum at the 3-5 months age group. Then, prevalence of antibodies to both serotypes increased after 6 months old, and nearly reach to 100% by the third year of life. The antibody titer to both HAstVs in sera revealed same pattern of antibody prevalence. The sera collected during epidemic season between January and June, had more higher titer of antibody to HAstVs than sera of non-epidemic season between July and December. Our results indicate that the infection of astrovirus in community may be more frequently than previous reports, and infection mainly occur in the 6-11 months age group.

Dysplasia epiphysealis hemimelica of the proximal tibia showing epiphyseal osteochondroma in an adult

A 33-year-old woman was referred to our hospital complaining of pain and a tumorous lesion in her left knee joint in the absence of any history of trauma. Radiological examinations demonstrated an osseous mass originating from the epiphysis of the proximal tibia, with a continuous osteoblastic lesion involving the lateral half of the epiphysis. The pathological diagnosis of these lesions was compatible with that of osteochondroma. The clinical and pathological features of this case were considered to be identical with those of dysplasia epiphysealis hemimelica, although this patient was older than patients described in previous reports, and demonstrated no other symptoms such as valgus or varus deformity or limb-length discrepancy.

[Trial of oral administration of Bifidobacterium breve for the prevention of rotavirus infections]

It was investigated that Bifidobacterium breve YIT4064 (B. breve YIT4064), Which had augmented IgA production and prevented rotavirus-induced diarrhea in mice, prevented rotavirus infection in infants. The effect of B. breve YIT4064 was evaluated in ten infants from an infants home who received 50 mg of the bacterium every day for 28 days (the B. breve group). Nine infants did not receive this (the control group). Though rotavirus shedding in the control group was detected from 2 (a total of 5 stool samples) of 9 infants (a total of 112 stool samples), it was not detected in any infants (a total of 133 stool samples) in the B. breve group during the administration period. From day 8 to day 14 of the test, rotavirus shedding was detected from 4 of 32 stool samples in the control group, but was not detected at all from 38 stool samples in the B. breve group. The frequency of rotavirus shedding in the B. breve group was significantly lower than that in the control group. Further, the frequency in appearances of anti-IgA in stool samples in the B. breve group showed a tendency to increase in comparison with the control group from day 8 to 14 of the test. The oral administration of B. breve YIT4064 significantly decreased rotavirus shedding in stool samples and prevented rotavirus infection.

Ankle-arm index as an indicator of atherosclerosis: its application as a screening method

The ankle-arm blood pressure index (AAI) is seldom used to screen for atherosclerotic diseases other than lower extremity arterial disease. This study was conducted to investigate whether the AAI can be used as a screening test for atherosclerotic diseases in general. The subjects were 446 male workers in a copper smelter. Fundoscopic examinations, electrocardiograms, serum cholesterol and triglyceride measurements, and AAI measurements were conducted. Information on past medical histories of diabetes mellitus and ischemic heart disease, smoking, alcohol intake, duration of sleep and physical activity were collected. The AAI correlated well with the results of the fundoscopic examinations, and an AAI of 1.00 gave the maximum sensitivity specificity product. The same AAI value also gave the maximum products for ST segment depression in electrocardiograms and the past history of ischemic heart disease. Multiple logistic regression analysis showed that a low AAI value was related to higher systolic blood pressure and current smoking but was inversely related to alcohol intake. Our study validated the AAI in predicting persons with risk factors of atherosclerotic diseases. The AAI measurements can be conducted at low cost, using simple techniques, and are noninvasive. We propose that the AAI be widely used to screen for atherosclerotic diseases.

Intensive care unit prognostic scoring systems to predict death: a cost-effectiveness analysis

OBJECTIVE

To evaluate the cost-effectiveness, using the technique of decision analysis, of withdrawing care from patients in the intensive care unit (ICU) who are predicted to have a high probability of death (>90%) after 48 hrs using a mortality risk estimate based on daily Acute Physiology and Chronic Health Evaluation (APACHE) III scores.

MATERIALS AND METHODS

A decision tree model was constructed to compare the cost-effectiveness of two clinical strategies. In the first strategy, patients receive ICU care until they were discharged, died, or had care withdrawn based on subjective clinical criteria. In the second strategy, patients remained in the ICU until they were either discharged, died, or had life-sustaining care withdrawn based on subjective criteria or if they were predicted to have a >90% risk of mortality after 48 hrs by a prognostic scoring system. Transition probabilities were based on a retrospective data analysis of 4,106 noncardiac ICU patients admitted to a tertiary surgical ICU over a 9-yr period. Cost estimates were based on daily Therapeutic Intervention Scoring System (TISS) scores from our database and using published data on the estimated production cost for a TISS point. The sensitivity (16.6%) and specificity (99.6%) of the mortality risk estimate at 48 hrs (using the >90% decision point) based on daily APACHE III scores were derived from published data.

RESULTS

In the base case analysis, we assumed that the sensitivity and specificity of the prognostic risk estimate are unchanged when exported to a new environment. Not using a prognostic scoring system as the basis for withdrawing care resulted in a slightly higher survival rate (87.2% vs. 86.85%) at a cost-per-death prevented (CPDP) of $263,700. Since prognostic scoring systems have not been shown to retain the same predictive power when exported to new databases, we chose to explore the effect of varying the specificity of the scoring system on CPDP. Decreasing the specificity from .996 (baseline) to .98 causes the CPDP to drop to $53,300. Changing the specificity to .95 results in a CPDP prevented of $21,700. Using one-way sensitivity analysis, the CPDP is shown to be relatively insensitive to delaying the decision point from ICU day 3 to day 7. Sensitivity analysis also indicates that CPDP increases rapidly with hospital death rate. For a death rate of 30%, the CPDP increases to $768,600 (in the base case, the death rate is 12.8%); when the specificity is decreased to .95, the CPDP drops to $62,100.

CONCLUSION

Unless daily mortality risk estimates based on APACHE III can be shown to retain the same level of predictive power in ICUs outside the development database, it is unlikely that the incremental cost-effectiveness gained by using them as the basis to withdraw care is sufficient to justify their use in this manner.

Death activation does not stop tumor growth: quantitative evidence for concomitant activation of apoptosis in tumor growth in vitro

A protein-independent fibrosarcoma, Gc-4 PF, grows exponentially in a protein-free medium. The doubling time (approximately 26 h) was similar to that of the serum-dependent parental clone, Gc-4 SD cultivated in the presence of fetal calf serum (FCS). We demonstrated here that the protein-free cultivation of Gc-4 PF cells concomitantly activates apoptotic phenotypes (one third of total cell population), including typical morphology, high uptake of Hoechst 33342 dye, and cleavage of DNA to large fragments, as observed in protein-deprived Gc-4 SD cell previously. Gc-4 SD cells arrested in the G0/G1-phase in response to the protein-free condition. In contrast, Gc-4 PF cells did not reach G0/G1 arrest in the protein-free condition; instead the durations of both G0/G1 and G2-phases were markedly reduced. The estimation of one cell cycle duration revealed that the cell division cycle was accelerated to 1.7 (27 h/15.4 h)-fold. Then the growth kinetics was able to be verified quantitatively by both the cell division rate and apoptotic cell loss. Protein-free cultivation resulted in slight down-regulation of c-myc protein in both cell types, while the down-regulation of p34cdc2, shown clearly in Gc-4 SD cells, was avoided in Gc-4 PF cells. Interestingly, while the expression of p53 was not affected in Gc-4 SD cells in response to the protein-free condition, the suppressor gene product expression was suppressed markedly in Gc-4 PF cells. These results suggest that Gc-4 PF cells may have acquired an ability to accelerate cell division by shortening the cell cycle duration to maintain a proper growth rate in response to intrinsic apoptosis activation with, at least in part, a suppression of p53 expression as well as an escape of down-regulation of p34cdc2.

Allotype immunoglobulin enhances alkaline phosphatase activity: implications for the inflammatory response

To understand the interactions among components of the immune/inflammation response, we studied the effects of immunoglobulins on the phosphatase activity of alkaline phosphatase in vitro. Bovine intestinal alkaline phosphatase was incubated with substrate in the presence of allotypic and xenotypic immunoglobulin. We found that bovine but not rabbit immunoglobulin enhanced the phosphatase activity of bovine intestinal alkaline phosphatase. Similarly, human but not bovine immunoglobulin G enhanced human placental alkaline phosphatase activity. By enhancing alkaline phosphatase activity, immunoglobulins bound to alkaline phosphatase may assist physiologic transport functions and enhance resolution of the inflammatory response. Further, in clinical conditions with high immunoglobulin concentrations, the serum alkaline phosphatase recorded may have spuriously high values.

Coexpression of HGF and c-Met/HGF receptor in human bone and soft tissue tumors

To understand the interaction between hepatocyte growth factor (HGF) and its receptor c-Met on various bone and soft tissue tumors, their expressions were investigated by western blot analysis, immunohistochemistry and enzyme immunoassay. Western blot analysis revealed that c-Met protein was expressed in 21 (38.8%) of 54 tumors, which detailed to seven (25.9%) of 27 bone tumors and 14 (51.8%) of 27 soft tissue tumors. Most malignant fibrous histiocytomas (MFH) and all neurofibromas expressed c-Met protein. The highest expression of c-Met protein was seen in a case of biphasic synovial sarcoma, where its immunoreactivity was localized only on the epithelial component and not on the sarcomatous component. By enzyme immunoassay for HGF, all but one MFH showed HGF production and the mean level of HGF was the highest among the tumors investigated. Neurofibromas and osteosarcomas had the next highest mean levels of HGF production, respectively. Coexpression of HGF and c-Met was observed in 19 (35.2%) of 54 tumors and was frequently observed in neurofibroma, followed by MFH and synovial sarcoma. Although the mode of interaction between HGF and c-Met varies among the various bone and soft tissue tumors including MFH, their signaling system may play an important role in the development and progression of bone and soft tissue tumors.

Imaging features of subcutaneous sarcoidosis

OBJECTIVE

This report describes subcutaneous sarcoidosis, focusing on the radiological and magnetic resonance (MR) features of the disease.

DESIGN AND PATIENTS

The cases of four patients (one male and three female, age range 36-75 years) who had subcutaneous sarcoidosis with no other organs affected were reviewed. Lesions were nodular in two cases, and in the other two were diffuse.

RESULTS

Computed tomography (CT) demonstrated a well-defined, homogeneous, and enhanced lesion in the nodular cases. However, in the diffuse cases, CT showed a heterogeneous, honeycomb-like appearance and little enhancement. Angiography showed a fine stain in the arterial phase. MR imaging of the nodular lesions was homogeneous with a signal intensity similar to muscle on T1-weighted images but heterogeneous with a higher signal than muscle on T2-weighted images. Diffuse lesions showed a striped or mesh pattern with intermediate signal intensity on both T1- and T2-weighted images. Contrast-enhanced MR images showed slight enhancement.

CONCLUSIONS

Subcutaneous sarcoidosis should be considered in the differential diagnosis when a patient presents with the radiological and MR features described.

Calcific tendinitis in the posterior proximal thigh as a self-limited condition: pathogenic role of inflammatory responses

OBJECTIVE

Calcific tendinitis occurs rarely in the posterior proximal thigh. We investigated whether it is self-limited and how the natural course of the disease progresses.

METHODS

We treated 6 patients with no surgical intervention, and analyzed laboratory and radiological findings in the followup period of more than one year (average followup, 2.5 yrs).

RESULTS

Although tendinitis was severe, rapid relief was observed within 2 weeks (average 5 days). Radiological features including extraskeletal calcifications did not change within 2 weeks, and then improved by 6 weeks. Four of 6 cases showed abnormal laboratory variables. All elevated white blood cell counts and C-reactive protein levels improved within one week with clinical resolution. In comparison with time course of the symptoms, changes in the radiological findings over time appeared not to be parallel with the clinical course, but laboratory progression appeared to correspond well with clinical resolution.

CONCLUSION

Inflammatory responses to hydroxyapatite crystals may play a role in the pathogenesis of symptoms of calcific tendinitis in the posterior proximal thigh, most of which are self-limited.

Air bubbles in the subclavian or internal jugular veins: a common finding on contrast-enhanced CT

We investigated the frequency of air bubbles in the subclavian (SCV) or internal jugular (IJV) vein in 200 patients who underwent contrast-enhanced CT of the head and neck. Half the patients were reviewed retrospectively (group 1), while the other half were investigated prospectively after the radiologists who administered the contrast medium were instructed to be careful not to inject even a single air bubble during the procedure (group 2). Air bubbles were observed in the SCV or IJV in 15 of the 100 patients in group 1, while in group 2, there were 4 such patients. Air injection, a common "complication", can be reduced by care during the procedure.

Aneurysm of a persistent sciatic artery

We report a case of an aneurysm of a persistent sciatic artery which caused buttock pain. Preoperative diagnosis is very difficult. However, awareness of the presence of this rare embryonic abnormality is important, especially in elderly persons with atherosclerotic changes. Sagittal magnetic resonance imaging (MRI) was very useful in reaching this diagnosis.

Overgrowth of the ischial tuberosity complicating femoral bone and muscle atrophy: implications for a delayed complication of malunited apophyseal avulsion fracture

Delayed complications occurring several years after the fused avulsion of ischial tuberosity have rarely been reported. We present a patient with overgrowth of the ischial tuberosity who complained of knee pain associated with significant bone and muscle atrophy in the thigh, which occurred 10 years after the ischial injury. Reinforcement exercise of the hamstrings relieved the knee pain. Here, we emphasize that avulsion fractures of the ischial tuberosity can cause persistent disability and that patients with avulsion fracture of the ischial apophysis in the adolescent period should actively maintain the strength of the hamstrings, even after more than 1 decade.

Throwing injury of the elbow: assessment with gradient three-dimensional, fourier transform gradient-echo and short tau inversion recovery images

We assessed MR findings of throwing injuries occurring in the elbow joint using three-dimensional Fourier transform (3DFT) and short tau inversion recovery (STIR) images. MR images of 63 elbows in 63 male patients aged from 10 to 32 years (mean age, 15 years 11 months) suffering from throwing injury were visually analyzed. The sequences used for the study were axial 3DFT and coronal STIR. Full-thickness tears were demonstrated in 34 elbows and undersurface tears of the ulnar collateral ligament (UCL) were demonstrated in five elbows. Thirty loose bodies were detected in 14 elbows. Cartilaginous damage due to osteochondral injury was depicted in 21 elbows. Multiplanar reformatted images using the 3DFT data set were useful for assessing torn UCLs, intraarticular loose bodies, and capitellar fragments. Full-thickness tears and undersurface tears of the UCL could be differentiated with STIR images. 3DFT and STIR sequences depict various aspects of throwing injuries occurring in the elbow.

Phasic increase of monoamine-related electrochemical signal in the rat caudate nucleus following conditioned auditory stimulation during the reaction-time task

Monoamine-related electrochemical signal was measured by in vivo chronoamperometry at a sampling rate of 5 Hz with a Nafion-coated carbon fiber placed in the caudate nucleus of the rat (n=5) performing an auditory reaction-time task. During the task, the rat pressed a lever in response to a tone stimulus to get food reward. An averaging technique was employed to extract event-related changes in monoamine concentration with respect to the tone stimulus, lever pressing or feeding. It was found that the oxidation current increased phasically for several seconds following the tone presentation with the mean onset latency being 0.4+/-0.2 s. Lever pressing was preceded by the onset of increase in two rats. Prominent increase was not observed following the tone presentation during the resting state, passive feeding, and lever pressing unrelated to the task. The results indicate that phasic increase in monoamine concentration occurs at the caudate nucleus in response to conditioned auditory stimulation in the reaction-time task. This response is not simply the consequence of sensory stimulation, motor reaction, or feeding, but is possibly influenced by integrative processes. The present electrochemical findings are consistent with the previous electrophysiological data on dopamine neuronal activity. However, pharmacological researches will be necessary in order to determine the substance involved in the phasic response.

[Prevalence of human astrovirus serotypes in Shizuoka 1991-96]

A latex agglutination test (LA) for astrovirus types 1-4 detection and typing was used on rotavirus- and adenovirus-negative stool samples from children with diarrhea between 1991 and 1996. Of the 478 samples tested, 30 were identified as astrovirus-positive. Most of the patients with astrovirus infections were under 2 years old. Astrovirus type 1 was the most prevalent serotype; 20/30 (66.7%), followed by type 4 (16.7%), type 3 (13.3%), and type 2 (3.3%). A prevalence of astrovirus-associated diarrhea was observed between January and June each year.

The rise time of the monophasic action potential--a new index of local use-dependent conductivity by sodium channel blockers in human myocardium

The kinetics of global use-dependent conduction slowing produced by sodium channel blockers in the human heart, estimated as a change in the QRS width, are known to be similar to those of use-dependent block of the maximum rate of depolarization in in vitro studies. However, the kinetics of the regional use-dependent decrease in conductivity have not been investigated. We examined whether the rise time of the monophasic action potential would be clinically useful as a marker of the local use-dependent decrease in conductivity by sodium channel blockers. In 12 patients without organic heart disease, monophasic action potentials (MAPs) were recorded at the right ventricular endocardium using a contact electrode before and after the administration of disopyramide (n = 6, 2 mg/kg, i.v.) or pilsicainide (class Ic agents, n = 4, 1 mg/kg, i.v., and n = 2, 150 mg, po) while the stimulus frequency was abruptly increased from 100/min to 150/min. The rise time, defined as the interval from the pacing pulse to the first peak deflection of the monophasic action potential, and the ORS width were measured simultaneously. In the absence of the sodium channel blockers, the abrupt increase in heart rate did not alter the QRS width or the rise time. In the presence of the agents, both variables were lengthened exponentially. The rate constants of onset changes in the QRS width and the rise time were 2.1 +/- 0.5 beats and 2.1 +/- 0.4 beats after the administration of disopyramide, and 7.5 +/- 3.0 beats and 8.2 +/- 4.0 beats after pilsicainide, respectively. The rate constant of the rise time was closely correlated with that of the QRS width. The present results are very closely comparable with the onset rate constants of use-dependent block of the maximum rate of depolarization in in vitro studies. These results suggest that (1) the rise time is a good indicator of local use-dependent decrease in conductivity by sodium channel blockers in human hearts and (2) the local use-dependent decrease in conductivity has kinetics similar to those of use-dependent sodium channel blocks.

[Nocturnal pulmonary hypertension in patients with obstructive sleep apnea associated with daytime pulmonary hypertension]

We investigated the effect of state-specific changes associated with REM sleep on pulmonary artery pressure in patients with obstructive sleep apnea (OSAS). Six male patients with OSAS (age; 40 +/- 12 SD yrs, BMI; 39.0 +/- 8.6 kg/m2, AHI; 51.5 +/- 28.5) were examined throughout the night by polysomnography, while monitoring pulmonary artery pressure via right cardiac catheterization. All patients had pulmonary hypertension (PH) during periods of wakefulness, and their mean pulmonary artery pressure (PAPm) was 31.1 +/- 7.4 mmHg. PAPm was analyzed at two different points in each apneic episode. PAPbase was the baseline value when inspiratory effects during apnea were not elicited, and PAPpeak was the peak value observed just after the cessation of OSA. PAPpeak was higher in REM (56.3 +/- 12.4) than in NREM (41.4 +/- 6.9 mmHg; P < 0.01), and both values were significantly higher than those observed during periods of wakefulness. The magnitude of elevation of PAP (delta PAP; PAPpeak-PAPbase) in REM and NREM were 11.6 +/- 2.0 and 6.9 +/- 2.8 mmHg, respectively. Relative ratios in the response of PAP to a decrease in O2 desaturation (delta PAP/delta SpO2) showed almost the same value for REM (-0.57 +/- 0.27) and NREM sleep (-0.57 +/- 0.26 mmHg/%). The values of PAPm at SpO2 75% were significantly higher in REM than in NREM (48.7 +/- 11.2 vs. 41.6 +/- 6.2 mmHg). We conclude that transient pulmonary hypertension could be caused not only by hypoxia, but also by state-specific responses (which are unrelated to hypoxia) that occur during REM sleep.