Impact of diabetes mellitus and triglyceride glucose index on mortality and cardiovascular outcomes in patients with chronic coronary syndrome undergoing coronary computed tomography angiography

Background

There is limited knowledge regarding whether an elevated triglyceride glucose (TyG) index can serve as a prognostic marker for mortality and cardiovascular outcomes, independent of diabetes mellitus (DM) and plaque burden, in patients with chronic coronary syndrome (CCS).

Methods

Patients with CCS (n = 684) were categorized into subgroups based on the presence of DM, and patients without DM were further divided into two groups based on presence or absence of an elevation of TyG index >8.8. Coronary plaque burden was evaluated using coronary computed tomography angiography. Major cardiovascular adverse event (MACE) was defined as a composite event of nonfatal myocardial infarction, unstable angina or unplanned coronary revascularization, stroke, non-cardiovascular mortality and cardiovascular mortality.

Results

Patients without DM exhibited significantly greater plaque and epicardial adipose tissue volumes than those with DM. Multivariable Cox proportional hazards models demonstrated that DM and an elevated TyG index >8.8 were independently associated with the risk of MACE after adjusting for age, sex, and plaque volume. Patients with DM (hazard ratio, 3.74; 95% confidence interval, 1.97-7.08; p < 0.001) and patients without DM with an elevated TyG index (hazard ratio, 1.99; 95% confidence interval, 1.01-3.91; p = 0.045) had an increased risk of MACE.

Conclusion

This study indicates that DM and an elevated TyG index are predictors of MACE, independent of plaque volume, in patients with CCS.

Thoracic Aortic Plaque Burden and Prediction of Cardiovascular Events in Patients Undergoing 320-row Multidetector CT Coronary Angiography

AIM

Wide volume scan (WVS) coronary computed tomography angiography (CCTA) enables aortic arch visualization. This study assessed whether the thoracic aortic plaque burden (TAPB) score can predict major cardiovascular adverse events (MACE) in addition to and independently of other obstructive coronary artery disease (CAD) attributes.

METHODS

This study included patients with suspected CAD who underwent CCTA (n=455). CCTA-WVS was used to assess CAD and the prognostic capacity of TAPB scores. Data analysis included the coronary artery calcification score (CACS), CAD status and extent, and TAPB score, calculated as the sum of plaque thickness and plaque angle at five thoracic aortic segments. The primary endpoint was MACE defined as a composite event comprised of ischemic stroke, acute coronary syndrome, and cardiovascular death.

RESULTS

During a mean follow-up period of 2.8±0.9 years, 40 of 455 (8.8%) patients experienced MACE. In the Cox proportional hazards model adjusted for clinical risks (Suita cardiovascular disease risk score), we identified TAPB score (T3) as a predictor of MACE independent of CACS ＞400 (hazards ratio [HR], 2.91; 95% confidence interval [CI], 1.26-6.72; p=0.012) or obstructive CAD (HR, 2.83; 95% CI, 1.30-6.18; p=0.009). The area under the curve for predicting MACE improved from 0.75 to 0.795 (p value=0.008) when TAPB score was added to CACS ＞400 and obstructive CAD.

CONCLUSIONS

We found that comprehensive non-invasive evaluation of TAPB and CAD has prognostic value in MACE risk stratification for suspected CAD patients undergoing CCTA.

Aortic arch plaque morphology in patients with coronary artery disease undergoing coronary computed tomography angiography with wide-volume scan

BACKGROUND

Wide-volume scanning with 320-row multidetector computed tomography coronary angiography (CTCA-WVS) enables the assessment of the aortic arch plaque (AAP) morphology and coronary arteries without requiring additional contrast volume. This study aimed to investigate the prevalence of AAPs and their association with coronary artery disease (CAD) and major adverse cardiovascular events (MACEs) in patients who underwent CTCA-WVS.

METHODS

This study included 204 patients without known CAD (mean age, 65 years; 53% men) who underwent CTCA-WVS. We evaluated the presence of aortic plaques in the ascending aorta, aortic arch, and thoracic descending aorta using CTCA-WVS. Large aortic plaques were defined as plaques of at least 4 mm in thickness. A complex aortic plaque was defined as a plaque with ulceration or protrusion. MACEs were defined as composite events of cardiovascular (CV) death, nonfatal myocardial infarction, and ischemic stroke.

RESULTS

AAPs and large/complex AAPs were identified in 51% ( n = 105) and 18% ( n = 36) of the study patients, respectively. The prevalence of AAPs with large/complex morphology increased with CAD severity (2.1% in no CAD, 12% in nonobstructive CAD, and 39% in obstructive CAD). The univariate Cox hazard model demonstrated that the predictors associated with MACEs were diabetes, obstructive CAD, and large/complex AAPs. Independent factors associated with large/complex AAPs were male sex [odds ratio (OR), 2.90; P = 0.025], stroke history (OR, 3.48; P = 0.026), obstructive CAD (OR, 3.35; P = 0.011), and thoracic aortic calcification (OR, 1.77; P = 0.005).

CONCLUSION

CTCA-WVS provides a comprehensive assessment of coronary atherosclerosis and thoracic aortic plaques in patients with CAD, which may improve the stratification of patients at risk for CV events.

Determinants of Non-calcified Low-Attenuation Coronary Plaque Burden in Patients Without Known Coronary Artery Disease: A Coronary CT Angiography Study

Background

Although epicardial adipose tissue (EAT) is associated with coronary artery disease (CAD), it is unclear whether EAT volume (EAV) can be used to diagnose high-risk coronary plaque burden associated with coronary events. This study aimed to investigate (1) the prognostic impact of low-attenuation non-calcified coronary plaque (LAP) burden on patient level analysis, and (2) the association of EAV with LAP volume in patients without known CAD undergoing coronary computed tomography angiography (CCTA).

Materials and Methods

This retrospective study consisted of 376 patients (male, 57%; mean age, 65.2 ± 13 years) without known CAD undergoing CCTA. Percent LAP volume (%LAP, <30 HU) was calculated as the LAP volume divided by the vessel volume. EAT was defined as adipose tissue with a CT attenuation value ranging from −250 to −30 HU within the pericardial sac. The primary endpoint was a composite event of death, non-fatal myocardial infarction, and unstable angina and worsening symptoms requiring unplanned coronary revascularization >3 months after CCTA. The determinants of %LAP (Q4) were analyzed using a multivariable logistic regression model.

Results

During the follow-up period (mean, 2.2 ± 0.9 years), the primary endpoint was observed in 17 patients (4.5%). The independent predictors of the primary endpoint were %LAP (Q4) (hazard ratio [HR], 3.05; 95% confidence interval [CI], 1.09–8.54; p = 0.033] in the Cox proportional hazard model adjusted by CAD-RADS category. Cox proportional hazard ratio analysis demonstrated that %LAP (Q4) was a predictor of the primary endpoint, independnet of CAD severity, Suita score, EAV, or CACS. The independent determinants of %LAP (Q4) were CACS ≥218.3 (p < 0.0001) and EAV ≥125.3 ml (p < 0.0001). The addition of EAV to CACS significantly improved the area under the curve (AUC) to identify %LAP (Q4) than CACS alone (AUC, EAV + CACS vs. CACS alone: 0.728 vs. 0.637; p = 0.013).

Conclusions

CCTA-based assessment of EAV, CACS, and LAP could help improve personalized cardiac risk management by administering patient-suited therapy.

Reverse Takotsubo Cardiomyopathy as a Cause of Acute Chest Pain in a Young Woman Following COVID-19 Vaccination

Supplemental Digital Content is available in the text.

Epicardial adipose tissue volume is associated with low-attenuation plaque volume in subjects with or without increased visceral fat: a 3-vessel coronary artery analysis with CT angiography

Background

Low-attenuation plaque (LAP) with a CT value of less than or equal 30 HU on coronary CT angiography (CCTA) is a marker of high-risk plaque features that leads to future acute coronary syndromes. Perivascular and epicardial adipose tissue (EAT) have been shown to be associated with progression of high-risk coronary plaques through metabolic and inflammatory mechanisms. However, association of EAT with LAP volume in three coronary arteries in subjects with or without visceral obesity remain unclear.

Aims

This study aimed to investigate the association of EAT volume (EAV) and coronary 3-vessel LAP volume in subjects with or without visceral obesity who underwent CCTA.

Methods

Patients who underwent CCTA without known coronary artery disease were included in the study (525 patients). Study subjects were classified as having non-obstructive or obstructive coronary artery disease according to the degree of coronary artery stenosis on CCTA. The plaque volume and EAV of the main vessel of the left anterior descending artery, left circumflex artery, and right coronary artery were measured with VINCENT software. Coronary plaque composition was classified as calcified plaque (CP, &gt;150HU), noncalcified plaque (NCP, 30–150HU), and Lap (&lt;30HU). The %LAP volume of the three coronary arteries was classified into quartiles. Multiple logistic regression analysis was used to analyze the factors associated with the %LAP volume.

Results

Compared with subjects without increase visceral fat, subjects with increased visceral fat had a significantly higher BMI, a greater total plaque volume, a greater total %LAP volume, a greater EAV, and a lower mean CT value of EAT. A significant correlation was observed between EAV and %LAP volume (R=0.24, p&lt;0.001). EAV (odds ratio; 1.83, 95% confidence interval 1.071–3.141, p-value 0.027) and type 2 diabetes mellitus (odds ratio 1.76, 95%confidence interval 1.042–3.000, p-value 0.034) appeared to be independent predictors of %LAP volume (Q4), when adjusted by age, gender, BMI&gt;25 kg/m2, visceral fat &gt;100cm2, LogCRP, coronary artery calcium score&gt;300, and obstructive coronary artery disease requiring revascularization.

Conclusion

This study suggests that LAP volume, which reflects the high-risk plaques in the three coronary arteries, is associated with EAV in subjects with or without increased visceral fat. Further research is needed whether pharmacological therapeutic intervention enables the prevention of coronary plaque progression and destabilization through the reduction of EAV in patients.

Funding Acknowledgement

Type of funding sources: None.

Evaluation of RAST in atopic dermatitis

Eighty-two patients with atopic dermatitis were examined for specific IgE antibodies by RAST. A higher number of positive RAST reactions were found in patients with high serum IgE values and with coexisting asthma and/or allergic rhinitis. Positive RAST reactions against mite and house dust were found in many of these patients and even in about one-half of patients with atopic dermatitis only. The comparisons between intradermal tests and RAST were made with various allergens and the mite extract showed the best agreement between these two tests.

Massive intrathoracic haemorrhage after CT-guided lung biopsy

CT-guided lung biopsy is now widely performed for tumorous lesions in the lung, and both its usefulness in this context and the associated complications have been well described in the literature. Although severe complications are rare, we describe a case in which massive intrathoracic haemorrhage developed after lung biopsy and necessitated emergency operation for control. Intraoperative findings suggested that the source of the haemorrhage was a fibrous, cord-like substance present at the site of adhesion associated with old tuberculosis. We attributed this haemorrhage to a pneumothorax, which developed after lung biopsy and caused the new vessels penetrating the centre of the fibrous, cord-like substance to stretch and rupture. Numerous cases have been reported of spontaneous haemopneumothorax precipitated by spontaneous pneumothorax and resulting from the rupture of such vessels.

[A recurrent case of amebic liver abscess seventeen years after the first occurrence]

A 49-year-old male who had been diagnosed as having amebic liver abscess when he was 32-year-old was admitted to our hospital with fever and watery diarrhea. Ultrasonography and CT examination demonstrated a solitary abscess in the right lobe of the liver. Cysts of Entamoeba histolytica were detected in the stool and an aspiration of the liver abscess looked like anchovy paste. Serum amebic antibody by the IFA method was positive and the case was diagnosed as amebic liver abscess. The patient was treated with metronidazole, and percutaneous transhepatic abscess drainage was performed. The liver abscess decreased remarkably in size and serum amebic antibody was negative after the treatment. Recurrence of amebic liver abscess is rare and we report this case with some literature.

Stimulative effects of saponin from kikyo-to, a Japanese herbal medicine, on pancreatic exocrine secretion of conscious rats

Our previous report stated that kikyo-to, a Japanese herbal medicine, consisting of the roots of Platycodon grandiflorum and Glycyrrhiza sp., stimulates the pancreatic exocrine secretion of conscious rats. The present study focused on the effective components of kikyo-to and the mechanism of stimuli to pancreatic secretion of rats. When 10 to 100 mg of platycodin D, a saponin from the root of Platycodon grandiflorum, was intragastrically administered, the pancreatic secretion of rats was stimulated. At the same time, the plasma CCK concentration increased. On the other hand, the stimulative effects of glycyrrhizin, a saponin from the root of Glycyrrhiza sp. were weak compared to platycodin D. The effects of 10 mg/kg of platycodin D on pancreatic secretion were inhibited by loxiglumide (50 mg/kg, i.g.), a CCK receptor antagonist. In contrast, the suppressive effect of atropine (300 micrograms/kg/h, i.v.) on pancreatic secretion was reduced by administering 10 mg/kg of platycodin D. In addition, up to 1 mM of platycodin D did not inhibit the trypsin activities in vitro. In conclusion, kikyo-to serves to stimulate pancreatic exocrine secretion mainly because platycodin D causes gastrointestinal hormones, particularly, CCK to be released from the duodenum.

Decreased contractile effect of endothelin-1 on hyperplastic prostate

1. The contractile activity, binding activity and localization of endothelin (ET)-1 were evaluated in human nonhyperplastic (control) and hyperplastic prostates. 2. ET-1 caused contraction of both prostates in a dose-dependent manner. However, this contraction was markedly decreased in hyperplastic prostates. 3. Bmax and Kd values of hyperplastic prostates were greater than those of the control. 4. The muscle and proliferative epithelium of hyperplastic prostates showed strong staining for the anti-ET-1 antibody. However, the glandular epithelium of control prostates was weakly stained. 5. These findings indicate that responsiveness to ET-1 is decreased, though the ET-1 and ET-1 receptors increase in the hyperplastic prostate. Namely, the increase in ET-1 receptors is not effective in regulating the contractile response of the prostate, because its expression is rather dominant in proliferated gland. 6. These suggest that ET-1 may not have an important role in the release of the obstructive symptoms of benign prostatic hypertrophy.

Multidirectional contraction of human hypertrophied prostate

1. The purpose of the present investigation is to evaluate muscle contraction in two directions (longitudinal and circumferential to urethra) physiologically and morphologically for alpha-adrenoceptor agonists. 2. Norepinephrine (10(-7)-10(-4) M), phenylephrine (10(-7)-10(-4) M) and clonidine (10(-7)-10(-4) M) induced contractions in a dose-dependent manner on human prostate from patients with benign prostatic hypertrophy (BPH). 3. No significant differences were observed between longitudinal and circumferential directions of human prostate in 50% of the maximal muscle contraction (EC50 values) and the maximal muscle contractions caused by any agents used. 4. Morphometric analysis for muscle in prostates was performed using formalin-fixed, paraffin-embedded sections stained by the Mallory-Azan method. 5. There was no significant difference in the density of the muscle area between longitudinal and circumferential directions of prostatic strips. 6. These results suggest that there are no significant differences in responsiveness of alpha-adrenoceptor agonists and the smooth muscle contents in longitudinal and circumferential directions to urethra, for human hypertrophied prostate.

Effects of CD-832, a dihydropyridine derivative with a nitrate ester moiety on rabbit femoral artery and vein

We investigated the effects of CD-832 ((4R)-(-)-2-(nicotinoyl-amino)ethyl 3-nitroxypropyl 1,4-dihydro-2,6-dimethyl-4,3-nitrophenyl, 3,5-pyridine dicarboxylate), a dihydropyridine derivative with a nitrate ester moiety, on contractile responses in rabbit femoral arteries and veins. CD-832 (10(-8) to 10(-6) M and nifedipine inhibited the 64 mM KCl-induced and 10(-6) M norepinephrine-induced contractions of rabbit femoral arteries, while nitro compounds had no effect on the contractions. CD-832 (10(-8) to 10(-6) M) and nitro compounds inhibited the 10(-6) M norepinephrine-induced contractions in rabbit femoral veins, while other Ca2+ channel antagonists had little effect. The inhibitory effects of CD-832 (10(-7) M) on norepinephrine-induced contractions were antagonized by treatment with methylene blue (10(-5) M). These results indicate that CD-832 potently relaxes venous smooth muscle, and that it may be a useful agent for the treatment of angina pectoris.

Role of cyclic GMP in inhibitory effects of CD-349 in isolated blood vessels

1. We investigated the effects of CD-349, a dihydropyridine derivative with nitrate ester, on contractile responses induced by high K+, norepinephrine (NE) and Ca2+ in isolated rabbit aorta. 2. CD-349 (10(-9)-10(-5) M) and nifedipine (10(-9)-10(-5) M) equally inhibited the 64 mM KCl-induced contraction of the aortic strips in a concentration-dependent manner. 8-Br-cyclic GMP (10(-3) M) did not inhibit the KCl-induced contraction of the aortic strips. 3. CD-349 (10(-8)-10(-5) M) and 8-Br-cyclic GMP (10(-6)-10(-3) M) inhibited the 10(-6) M NE-induced contraction of the aortic strips in a concentration-dependent manner. However, nifedipine had no effect on the NE-induced contraction in rabbit aorta. 4. The inhibitory effects of CD-349 on NE-induced contraction were antagonized by treatment with methylene blue and oxyhemoglobin, while they were augmented by treatment with zaprinast. 5. CD-349 (10(-8)-10(-5) M) and 8-Br-cyclic GMP (10(-5)-10(-4) M) inhibited the NE-induced phasic contraction and Ca(2+)-induced contraction of the aortic strips preincubated with NE in Ca(2+)-free medium. However, nifedipine (10(-5) M) had little or no effect on both NE-induced phasic contraction and Ca(2+)-induced contraction of the aortic strips preincubated with NE in Ca(2+)-free medium. 6. CD-349 (10(-7)-10(-5) M) increased the levels of cyclic GMP in rabbit aorta. 7. These results indicate that CD-349 has a hybrid property deriving from Ca(2+)-antagonist and cyclic GMP increasing agents.

CD-832, a new dihydropyridine derivative with both nitrate-like and Ca2+ channel antagonist vasodilator activities

We investigated the effects of CD-832 ((4R)-(-)-2-(nicotinoylamino)ethyl 3-nitroxypropyl 1,4-dihydro-2,6-dimethyl-4,3-nitrophenyl, 3,5-pyridine dicarboxylate), a new dihydropyridine derivative with nitrate ester, on contraction and relaxation responses induced by various vasoactive agents in rabbit aorta. CD-832 potently inhibited the specific binding of [3H](+)-PN200-110 to rat brain membranes. The IC50 values for [3](+)-PN200-110 binding were 2.8 nM and 4.9 nM in CD-832 and nifedipine, respectively. CD-832 (10(-8) to 10(-5) M), diltiazem (10(-8) to 10(-5) M) and benidipine (10(-8) to 10(-5) M) inhibited the 64 mM KCl-induced contraction of the aortic strips in a concentration-dependent manner. Neither nitroglycerin (10(-8) to 10(-5) M) nor nicorandil (10(-8) to 10(-5) M) affected the 64 mM KCl-induced contraction in rabbit aorta. CD-832 (10(-8) to 10(-5) M), nitroglycerin (10(-8) to 10(-5) M) and nicorandil (10(-5) M) had no effect on norepinephrine-induced contraction in rabbit aorta. Nitroglycerin (10(-5) M), atrial natriuretic peptide (10(-8) M), nicorandil (10(-5) M) and CD-832 (10(-7) to 10(-5) M) augmented the isoproterenol-induced relaxation responses of rabbit aorta precontracted with endothelin-1 (1 x 10(-7) to 2 x 10(-7) M). The effects of nitroglycerin (10(-5) M), nicorandil (10(-5) M) and CD-832 (10(-5) M) on isoproterenol-induced relaxation responses were antagonized by treatment with methylene blue (10(-5) M) and oxyhemoglobin (10(-5) M).(ABSTRACT TRUNCATED AT 250 WORDS)

[Two cases of early Acanthamoeba keratitis]

Early Acanthamoeba keratitis was diagnosed in two soft contact lens wearers. Both patients had initially been diagnosed as having herpes simplex keratitis and treated with antiherpes drugs. In one patient, slit-lamp examination disclosed dendritiform epithelial keratitis, subepithelial opacities, linear stromal infiltrate along the corneal nerve (radial keratoneuritis), and marked swelling and hyperemia of the limbal conjunctiva. Acanthamoeba castellanii was cultured from the corneal scrapings and contact lens case. The second patient also showed dendritiform keratitis and subepithelial opacities, with swelling of the limbal conjunctiva. Cultures were positive for A. polyphaga from the contact lens case, but negative from the corneal scrapings. The patients were cured of Acanthamoeba keratitis with medical therapy consisting of topical fluconazole and miconazole, systemic fluconazole, and topical corticosteroids. Recognition of distinctive characteristics of the clinical findings in early Acanthamoeba keratitis can lead to the early diagnosis of the disease.

Impairment of endothelium-dependent relaxation of superior mesenteric artery in genetically diabetic WBN/Kob rats

The endothelium-dependent relaxation of superior mesenteric arteries of Wistar and genetically diabetic WBN/Kob rats was compared. Endothelium-dependent relaxation induced by acetylcholine (ACh) and A23187 was depressed in WBN/Kob rats. Relaxation induced by sodium nitroprusside, an endothelium-independent agent, in strips from WBN/Kob rats was similar to that in strips from Wistar rats. Indomethacin (5 x 10(-6) M) enhanced the relaxation responses to ACh in strips from both WBN/Kob and Wistar rats; however, endothelium-dependent relaxation induced by ACh remained attenuated in WBN/Kob rats. These results show that endothelium-dependent relaxation is impaired not only in thoracic aorta but also in superior mesenteric arteries in genetically diabetic rats.

Effects of VA-045, a novel apovincaminic acid derivative, on isolated blood vessels: cerebroarterial selectivity

We investigated the effects of VA-045, an apovincaminic acid derivative, on isolated blood vessels. VA-045 (10(-7)-10(-5) M) and vinpocetine (10(-7)-10(-5) M) inhibited the 64 mM KCl-induced and 10(-6)M norepinephrine (NE)-induced contraction of rat aortic strips. VA-045 (10(-7)-10(-4) M) and vinpocetine (10(-7)-10(-4) M) inhibited the activity of cyclic AMP and cyclic GMP phosphodiesterase in porcine coronary artery. VA-045 (3 x 10(-9-3 x 10(-6) M) relaxed the 64 mM KCl-induced contraction of the canine basilar artery without affecting the peripheral arteries. These results indicate that VA-045 selectively dilates canine cerebral artery, and that it may be a useful agent for the treatment of cerebrovascular diseases such as stroke.

Effects of CD-349 and 8-BrcGMP on isoproterenol-induced relaxation in rabbit aorta precontracted with endothelin-1

We investigated the effects of CD-349, a dihydropyridine derivative, on isoproterenol (Iso)-induced relaxation in rabbit aorta precontracted with endothelin-1 (ET-1). The Iso (10(-8)-10(-5) M)-induced relaxation responses in rabbit aorta precontracted with 1-2 x 10(-7) M ET-1 were augmented by pretreatment with CD-349 (10(-9)-10(-5) M) in a concentration-dependent manner. The effects of CD-349 on Iso-induced relaxation of the aortic strips precontracted with ET-1 were inhibited by treatment with methylene blue (10(-5) M) and oxyhemoglobin (10(-5) M), whereas they were augmented by treatment with N omega-nitro-L-arginine (10(-4) M). The Iso-induced relaxation responses were also augmented by pretreatment with 8-Br-guanosine 3',5'-cyclic monophosphate (cGMP) (3 x 10(-6)-3 x 10(-4) M) in a concentration-dependent manner. However, nifedipine (10(-5) M) and nicardipine (10(-5) M) had no effect on Iso-induced relaxation responses of the aortic strips precontracted with 10(-7) M ET-1. CD-349 also augmented forskolin (10(-8)-10(-5) M)-induced relaxation responses of rabbit aorta in a concentration-dependent manner. CD-349 (10(-7)-10(-5) M) increased the levels of cGMP but not of adenosine 3',5'-cyclic monophosphate (cAMP) in a concentration-dependent manner in rabbit aorta without endothelium. Both CD-349 (10(-5) M) and 8-BrcGMP (3 x 10(-5) M) augmented the Iso-induced elevations of cAMP in rabbit aorta without endothelium. These results indicate that CD-349 and 8-BrcGMP can augment Iso-induced relaxation responses by enhancing the accumulation of cAMP.

Changes in responsiveness of the aorta to vasorelaxant agents in genetically diabetic rats: a study in WBN/Kob rats

The effects of various vasorelaxant agents on aortas from control and genetically diabetic rats were examined. The concentration-response curves for the isoproterenol (ISO)-induced relaxation of both aortic strips with and without endothelium are shifted to the right in diabetic rats. The relaxation responses of diabetic aorta to forskolin and vasoactive intestinal peptide did not differ from those of controls. The relaxation responses of diabetic aorta to cromakalim and nicorandil did not differ from those of controls. These results indirectly indicate that ISO-induced relaxation responses of the aortic strips from genetically diabetic rats decreased, and that this decreased relaxation response of the strips to ISO may be due to decreased density or affinity of beta adrenoceptors on the endothelium and vascular smooth muscle.

Biological nature of Cryptosporidium sp. isolated from a cat

A small type of Cryptosporidium oocysts was isolated from a naturally infected cat and its biological nature was investigated. In cats experimentally inoculated with Cryptosporidium oocysts, long-lasting shedding of the oocysts occurred after a prepatent period of 8-10 days, and a number of peaks of oocyst count appeared at intervals of several days to a few weeks, earlier in the infection course. Cryptosporidium infection in cats is likely to pass from an acute to a chronic stage. During the chronic stage, prednisolone injection into the cats gave rise to a recurrence of proliferation of the parasite along with a marked increase in the number of oocysts shed. None of the infected cats showed clinical symptoms. Infection experiments using Cryptosporidium oocysts were unsuccessful in several species of animals such as mice, rats, guinea pigs, dogs, suckling mice and mice previously injected with prednisolone or hydrocortisone.

Stage-specific response of preimplantation mouse embryos to W-7, a calmodulin antagonist

Involvement of calmodulin-dependent processes in preimplantation development of mouse embryos was studied with the use of N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide (W-7), a specific antagonist of calmodulin. At 25 microM, W-7 interfered with compaction of eight-cell embryos, caused decompaction of compacted eight-cell embryos, inhibited cavitation of late morulae, and caused collapse and degeneration of blastocysts. These effects of W-7 appear to be due to specific inhibition of calmodulin-dependent processes, because W-5, a less active analogue of W-7, was less effective in interfering with development; at 25 microM, W-5 had only a slight effect on compaction and had no effect on blastocyst formation, maintenance of blastocoels, or post-blastocyst development. In addition to the developmental effects just described, W-7 inhibited cell proliferation in four-cell embryos and reduced cell numbers of morulae after treatment at the two- to eight-cell stages. There was a marked increase in embryos' sensitivity to W-7 at the late morula stage, and the sensitivity increased further as embryos developed into blastocysts; the effects of W-7 were largely reversible after treatment at the two-cell through the compacted eight-cell stages, but not after treatment at the late morula or blastocyst stage. At the blastocyst stage, inner cell mass cells appeared to be slightly more resistant to W-7 than trophectoderm cells. This differential sensitivity became more pronounced at the late blastocyst stage: after 3.5-4-h exposure of late blastocysts to 25 microM W-7, all trophectoderm cells degenerated but most of the inner cell masses survived. From these results it appears that calmodulin-dependent processes are involved in development of mouse embryos at all of the preimplantation stages examined.

Brain atrophy and cerebral infarction

The subjects of the study (109 males, 48 females) were all diagnosed to have cerebral infarction by computerized tomography (CT). The cerebrospinal fluid (CSF) space volume and cranial cavity volume in the normal hemisphere of the patients were estimated using CT at the time from 1 to 3 weeks after the attack of cerebral infarction. The percentage of the CSF space volume to the cranial cavity volume was calculated as an indicator for brain atrophy and called brain atrophy index (BAI): BAI (%) = 100(%) X (CSF space volume/cranial cavity volume). The BAI immediately after the attack of infarction (6.6 +/- 2.2, n = 15), during which no detectable change occurred on CT examination, was the same as the BAI at the time from 1 to 332 days after the attack (6.6 +/- 2.4, n = 20). Therefore we compared the BAI in patients without infarction with the BAI in patients with infarction irrespective of secondary atrophy of the brain after the attack. The BAIs in males with infarction were significantly greater than the BAIs in males without infarction in the age of fifties, sixties and seventies. The BAIs in females with infarction were significantly greater than in females without infarction in the age of fifties, sixties and eighties.

Association of hypertension with increased atrophy of brain matter in the elderly

Atrophy of brain matter in hypertensive and normotensive subjects was studied by quantitative measurements of brain volume and cranial cavity volume using x-ray computed tomography. The 123 normotensive subjects ranged in age from 20 to 79 years and were divided into six ten-year age groups. The 67 hypertensive subjects ranged in age from 40 to 83 years and were divided into four age groups. Values of the brain volume index ( BVI ), the ratio of brain matter volume to cranial cavity volume, for hypertensives and normotensives in the same age groups were compared. Mean BVI values were significantly lower in hypertensives in the fifth (P less than 0.01), sixth (P less than 0.01), seventh (P less than 0.05) and eighth and ninth decades of life (P less than 0.001). Systemic hypertension, which may induce various diseases in the elderly, had a striking effect on atrophic changes of brain matter in elderly subjects.

[Comparative studies on 99mTc-pyrophosphate and 85Sr-chloride for skeletal imaging]

In order to know the potential merits of 99mTc-pyrophosphate (99mTc-PYP) skeletal imaging, a comparative study was carried out by administering to the rabbit 85Sr-chloride (85Sr), classical bone-seeking agent, and 99mTc-PY simultaneously. Radioisotopic distribution was investigated as regards their deposition in the pelvic bones, and sharpness of the skeletal scintigrams, too. Both agents were remarkably affinitive to the skeletal system and there were remarkably differences in their temporal deposition pattern. Marked deposition was observed of either agent in the metaphyses. With 99mTc-PYP, the vertebral and costal systems were delineated symmetrically and each vertebral body was distinctly depicted as such 99mTc-PYP many possess the following merits over 85Sr; (1) owing to its physical properties, sufficiently large radioactivity of 99mTc-can be administered; (2) body burden of radiation absorption is reduced; (3) skeletal scintigrams of high quality are obtainable in a short period of time.

Experimental pancreas imaging study with 13N-glutamate using positron computer tomography

Accumulation of 13N-L-glutamate in the pancreas was experimentally evaluated by tissue distribution studies and by positron computer tomography imaging studies. The pancreas and salivary gland of Donryu rats exhibited a high rate of 13N-glutamate uptake. The percent administered dose/g of pancreas was 3.8 at 20 min, 4.4 at 30 min after injection, and the pancreas to liver ratio was 1.9 and 2.5, respectively. The same results were obtained with Golden hamsters. The role of the feeding protocols was studied to optimize the technique. The fasting group showed a significantly higher uptake in the pancreas than in the free feeding group. The uptake in the fasting followed by a high protein meal group was higher than fasting only group, but the difference was not significant. Positron emission tomography of a miniature-pig with 13N-glutamate showed a clear image of the pancreas with the highest activity. It was concluded that 13N-glutamate was quite useful in positron imaging of the pancreas.

Age-related changes of the cranial bone mineral: a quantitative study with computed tomography

Age-related changes of the cranial bone mineral in 495 subjects were assessed by computed tomography (CT) in terms of the Hounsfield number. By means of computer programs available in the CT system, the histograms for the bone were obtained. The peak of this histogram for males increased gradually and reached a plateau beyond 20 years of age, while that for females rose rather steeply from age 0 to age 20 and formed a plateau in the 20s and 30s, then declined precipitously from a value of 1164 +/- 143 to a value of 629 +/- 119 in the 70s and older. In the 20s and 30s, the peak for females was greater than that for males. The total pixel number of this histogram was constant after the 20s. The pixel number of the peak for males made a plateau after the 10s, but that for females showed a similar pattern until the 40s, then increased steeply after the 50s. The peak may reflect calcium concentration of the cranial bone, and therefore the skull of the female may store more calcium than that of the male in the 20s and 30s.

Sex difference in brain atrophy during aging; a quantitative study with computed tomography

Brain atrophy in 154 men and 147 women without neurologic deficits was quantitatively studied by means of computed tomography. The ages ranged from 20 to 79 years. The volume percentage of brain to cranial cavity (Craniocerebral Index, or CCI) was calculated by means of computer programs available in CT systems. The mean CCI in the 20-39 age group was constant at 98.4 per cent in men and 98.7 in women, and this was considered the standard for the CCI in subjects with nonatrophied brains. The percentage of each subject's CCI in relation to this standard in both sexes (Brain Volume Index, or BVI) was calculated as the indicator of brain atrophy. The normal value for BVI was therefore 100 per cent in both sexes. A clear difference was observed between men and women in the process of brain atrophy with increasing age. In men a significant reduction in BVI began in the sixth decade of life (P less than 0.01); thereafter, the decline was gradual and steady through the eighth decade (P less than 0.05). In women, a significant reduction in BVI began in the fifth decade (P less than 0.01) and remained relatively constant during the fifth and sixth decades but declined significantly again in the seventh and eighth decades. In both sexes, remarkable individual differences in brain atrophy were characteristic.

Age-related brain atrophy and mental deterioration--a study with computed tomography

The relation of brain atrophy measured with computed tomography (CT) to mental deterioration on living people was studied. A newly improved technique for quantitative measurement of brain atrophy was developed. The pixels inside the head slices were divided into three parts; brain skull, and cerebrospinal fluid according to their CT number. The volume of brain, CSF, and cranial cavity were calculated by counting the number of pixels of each tissue. Results from 130 normal brains showed that the CSF volume was constant at about 16 ml through 20--39 years old. After 40 years the mean CSF volume increased drastically and reached 71 ml in the seventies. The volume of the brain was standardized for comparison between different-sized heads (brain volume index: BVI). The mean BVI decreased with statistical significance after 40 years of age. Mental function of these persons were evaluated using Hasegawa's dementia rating scale for the elderly. Progression of brain atrophy accompanied loss of mental activities (p less than 0.01).

Brain atrophy during aging: a quantitative study with computed tomography

Brain atrophy in 228 normal persons was quantitatively measured by computed tomography (CT), making use of computer programs available in the CT system. Pixels representing bone, brain, and cerebrospinal fluid in slices thru the head were counted by the computer. The volume percentage of the brain to the cranial cavity (Craniocerebral Index: CCI) was calculated from the pixel numbers. The CCI in 20 to 49-year-old adults was constant at 92 +/- 3. This value was considered the standard of normal brain and the percentage of the subject's CCI to this value (Brain Volume Index: BVI) was calculated as the indicator of brain atrophy. The BVI was rather low in children (97 +/- 5) and teenagers (96 +/- 3), and decreased drastically with increasing age after 50 years. The BVI in the 80s was as low as 89 +/- 6.

Tumor regrowth after irradiation; an experimental approach

Structural changes in irradiated tumors and their regrowth were studied in a rat hepatoma, AH109A, using histological and transparent-chamber techniques. The development of the tumour was examined by means of vascular morphometry as observed in the chamber. Schematically, the tumour tissue was divided into four isocentric layers according to vascular morphology and measurements of vessel volume, surface area, and length per mm3 of tissue. The vascularity was greatest in the outermost region, decreased towards the inner parts and reached an absence of vascularity at the central necrosis. The tumors were gamma- or X-irradiated with various doses. The inside hypoxic region was destroyed completely after 3000 rad, and regrowths started exclusively from the outermost area of the tumour where enhancement of the effect of radiation by oxygen was thought to be greatest. Possible mechanisms of tumour regrowth are discussed.