Two cases of nasopharyngeal branchial cyst

Two cases of nasopharyngeal cyst, in a two-year-old girl and a six-year-old boy, are described. The cysts were located in the right lateral wall of the nasopharynx in both cases. Histopathological examinations revealed that the cyst walls were lined with columnar epithelium. The positions of the cysts and pathological features indicated that they were of branchial origin, and they were assumed to originate in the second branchial pouch because of their anatomic location. They differed from previously reported cases in that they extended nearly to the base of the skull, occupying the parapharyngeal space. It was considered that they might have originated from the dorsal part of the second branchial pouch or the layer of endodermal cells cut off from the lower part of the eustachian tube.

A new aspect of the carotid body function controlling hypoxic ventilatory decline in humans

Ventilatory response to eucapnic sustained mild hypoxia was measured in one patient with unilateral and three patients with bilateral carotid body (CB) resection (defined UR and BR, respectively). The profile of ventilatory response in UR patient was initially augmented then gradually declined (biphasic pattern) as generally seen in normal subjects although the absolute magnitude was substantially low. On the other hand, biphasic pattern was disappeared in all three BRs. Lack of hypoxic ventilatory decline (HVD) in the late period of sustained hypoxia was in marked contrast to that reported in the anaesthetized and CB-denervated animals whose ventilation was severely depressed lower than the pre-hypoxic control level. In view of recent knowledge that the analogous mild hypoxia in normal animals and humans elicits an useful adaptation to economize energy expenditure with maintaining reversible excitability in control of respiration, BR patients were considered to have lost this ability. We conclude that in awake humans the CB not only stimulates ventilation but also controls the degree of subsequent HVD during sustained hypoxia.

Strength training with partial ischaemia stimulates microvascular remodelling in rat calf muscles

The effects of strength training with partial tourniquet ischaemia on skeletal muscle capillarity were examined, particularly in terms of the distribution of arteriolar and venular capillaries and their capillary domain area, in male Wistar rats. A tourniquet applied around the knee joint induced partial ischaemia. Repeated isometric contractions of calf muscles, 1 s on/1 s off for 3 min, induced by electrical stimulation (100 Hz), were conducted 2 days/week for 6 weeks as training. Morphologic data were obtained from four groups; non-treatment control (C), ischaemic (IS), non-ischaemic training (NIT) and ischaemic training (IT). In the superficial portion of gastrocnemius (GASs) muscle, the total capillary density of arteriolar capillaries was significantly greater in the IT-leg than in the C-leg (P < 0.05). In the plantaris (PL) muscle, these values were significantly greater in the IT-leg than in both the C- and NIT-legs (P < 0.05). Only in the GASs was the capillary-to-fibre ratio significantly greater in the IT-leg than in the C-leg (P < 0.05). In GASs and PL, the capillary domain area (CDA) was smaller in the IT-leg than in the C- and NIT-legs. In all muscles examined, mean fibre cross-sectional area was not significantly changed by the experimental treatment. These findings suggest that adaptive changes in the microvascular network, identified as an increase in the arteriolar capillary area and a reduction in diffusion distance, occur in the skeletal muscles after strength training with partial ischaemia. These adaptive changes probably improve the supply of oxygen and nutrients to skeletal muscle tissues.

Stable pulmonary capillary haemangiomatosis without symptomatic pulmonary hypertension

Pulmonary capillary haemangiomatosis is a rare disorder characterised by multiple angiomatous lesions composed of proliferating capillary vessels in the lung parenchyma that usually progress rapidly to establish fatal pulmonary hypertension. The 29 year old man presented here, however, has been stable for 3.5 years since the diagnosis without symptoms of pulmonary hypertension. High resolution computed tomographic findings of the pulmonary lesions seemed specific to the disease.

Time-course changes in arteriolar and venular portions of capillary in young treadmill-trained rats

This study was designed to examine the time-course changes in capillarity, especially the distribution of arteriolar and venular capillaries, in skeletal muscles during endurance training by running in young female Wistar rats. Exercise training by running started at the age of 5 weeks and lasted for 5 weeks at 25 m min(-1) on a 25% gradient, 10-60 min day(-1), 5 days per week. Morphological findings were obtained from the soleus (SOL) and deep portions of the medial gastrocnemius (GASd) muscles. In SOL, the training significantly increased the capillary-to-fibre ratio (C:F), total capillary density, and density of venular capillaries at Week 1. Significant increases in the C:F and total capillary density were also observed at Weeks 4 and 5. The capillary domain area (CDA) values for total capillary and arteriolar and venular capillaries were significantly decreased after 4 weeks of training. In GASd, the training significantly increased the C:F at Week 1 and from Week 3 onwards. It also significantly increased cross-sectional area of all fibre types. Total capillary density and the CDA values showed no significant difference between control and training groups at all points of time. Significant increases in succinate dehydrogenase (SDH) activity were first noted after 2 weeks in GASd and after 3 weeks in SOL. These findings suggest that, in young growing rats, adaptive changes in the oxygen transport system occurred within 1 week after the onset of training mainly in highly oxidative muscles. The changes in arteriolar and venular capillary densities may help to clarify the growth pattern of the capillary network associated with endurance running training.

A case of primary sarcoma of the pulmonary artery

A 39-year-old male was admitted complaining of nonproductive cough and dyspnea on exertion. Death occurred eight months after onset of the symptoms. Autopsy examination showed that the pulmonary trunk and left main pulmonary artery were markedly dilated and completely occluded by a tumor. The tumor had infiltrated into the left upper lobe and mediastinal lymph nodes, and metastatic nodules were found in both lungs and in the left adrenal gland. Small foci of infarction were noted in the lower lobes of both lungs. The tumor cells were of two types; pleomorphic spindle cells and bizarre multinucleated giant cells. Immunohistochemically, they were positive for vimentin, myosin, and lysozyme, but negative for desmin and muscle-specific actin. The cytoplasm of the tumor cells was showed by electron microscopy to contain microfilaments, dense bodies, and pinocytotic vesicles. We diagnosed this case as undifferentiated sarcoma of the pulmonary artery. Approximately 100 cases of pulmonary artery sarcoma have been reported. Histopathologically, almost all of the reported cases showed both spindle cells and pleomorphic giant cells, indicating a biologically anaplastic neoplasm.

[A case of primary pulmonary artery myxosarcoma associated with severe pulmonary hypertension]

A 50-year-old man presented with progressive dyspnea on exertion, but with no history of chest pain or syncope. Chronic pulmonary thromboembolism was suspected and he was referred to our hospital. On ausculation, a grade 3 systolic murmur was heard, that was loudest in the fifth intercostal space lateral to the right sternal border. Chest radiography showed mild cardiomegaly and ventilation-perfusion scan revealed absence of perfusion in the left lung and the upper field of the right lung. Contrast-enhanced helical CT showed large mural defects in both main pulmonary arteries, clearly delineated by contrast medium. The left pulmonary artery was nearly completely occluded, and eccentric defects were observed projecting into the lumen of the pulmonary trunk. A tumor originating in the pulmonary artery was suspected, but a definitive diagnosis of the mass could not be made with pulmonary angiography and magnetic resonance imaging. The mean pulmonary arterial pressure was 50 mmHg. Further radiologic examinations failed to reveal the source of the embolus or tumor. It was decided to attempt surgical excision under total cardiopulmonary bypass. At operation, a gelatinous, lustrous, yellowish mass was found partially occluding the right main pulmonary artery and completely occluding the left. The tumor adhered tightly to the intima of the vessel and was inoperable. The patient could not be weaned from percutaneous cardiopulmonary support and died 3 days after surgery. Histologic examination of the excised specimen revealed myxosarcoma.

Volume acceleration as an index of respiratory drive during exercise

In order to evaluate the applicability of volume acceleration (A(I)) at the onset of inspiration as an index of neuromuscular output, CO(2) rebreathing in six healthy subjects and incremental-load exercise in eight healthy subjects was performed while measuring A(I) and mouth occlusion pressure (P(0.1)). During CO(2) rebreathing, A(I) increased linearly with end-tidal CO(2) partial pressure and P(0.1). During incremental-load exercise, P(0.1) and A(I) increased exponentially with minute ventilation and mean inspiratory flow, and A(I) increased linearly with P(0.1). Dyspnoea sensation at rest and exercise with or without the circuit system in eight healthy subjects was examined. Dyspnoea sensation increased markedly with the circuit system in some subjects. Incremental-load exercise was carried out by 13 healthy subjects and 21 patients with chronic obstructive pulmonary disease (COPD) to evaluate the difference in A(I) as respiratory drive between the two groups in the absence of a respiratory circuit. In patients with COPD, A(I) responses to minute ventilation, mean inspiratory flow and carbon dioxide output (VCO(2)) were greater than those in healthy subjects. In patients with COPD, the A(I) response to VCO(2) was greater in those with a lower FEV(1.0) (forced expiratory volume in 1.0 s), but the ventilatory response to VCO(2) was lower in those with a lower FEV(1. 0). These data suggest that A(I) reflects neuromuscular output during CO(2) rebreathing and incremental-load exercise under conditions where mechanical properties of the respiratory system are expected to be involved. During exercise, flow increased markedly, and the influence of the resistance of the respiratory circuit also increased. Therefore the use of A(I) has the advantage of less resistance (no respiratory circuit) and less additional respiratory effort, in comparison with the use of P(0.1), especially in patients with COPD.

Current Trends in Computed Tomography Practices in Japan and the Role of Referring Physicians in Radiation Exposure Management

Introduction In 2020, Japan recorded the highest number of computed tomography (CT) units per million population among Organization for Economic Co-operation and Development (OECD) countries. This surplus may lead to unnecessary procedures, increased costs, and increased radiation exposure. This study estimated CT procedures per 1,000 population and analyzed their usage by sex and age using governmental surveys and health insurance claim data. Methods Data from 2008 to 2020 were obtained from the Ministry of Health, Labour and Welfare medical institution surveys. Age- and sex-specific data (2014-2022) were extracted from the Japanese National Database of Health Insurance Claims and Specific Health Checkups (NDB Open Data, Japan). The population data were sourced from the Ministry of Internal Affairs and Communications. Results The number of CT procedures performed per 1,000 population increased from 210 in 2008 to 283 in 2020. The number of CT procedures performed per unit increased from 2,170 in 2008 to 2,445 in 2020. NDB Open Data revealed an annual increase in CT procedures per 1,000 population, from 221 in 2014 to 255 in 2022. Men underwent more CT scans than women across all age groups, with CT procedures per 1,000 population increasing with age (e.g. in 2022, 27 in men 0-9 years old to 1,182 in men ≥90 years old and 18 in women 0-9 years old to 835 in women ≥90 years old). Conclusions The number of CT procedures performed per 1,000 population in Japan has steadily increased. With the highest OECD rates in 2017 and 2020, mitigating overuse requires a dose management system, referral guidelines, and education regarding radiation risks for referring physicians.

[A case of primary pulmonary artery sarcoma]

A 39-year-old male was admitted with persistent cough, palpitations and dyspnea on exertion. Chest X-ray showed cardiomegaly, left pleural effusion and left hilar mass shadow. Echocardiogram revealed dilatation and hypertrophy of the right atrium and ventricle. Perfusion lung scintigram disclosed a complete defect of the left lung and a partial defect of the right upper lobe. CT scan showed an intravascular tumor mass in the bilateral main pulmonary arteries. Digital subtraction angiography of the pulmonary artery revealed complete obstruction of the left pulmonary artery and stenosis of the right pulmonary artery. MR image showed intravascular tumor infiltrating the mediastinum and surrounding tissue. Sarcoma was highly suspected, but a histopathological diagnosis could not be made. The patient died of heart failure two months after admission to our hospital. Postmortem examination showed that the pulmonary trunk and left main pulmonary artery were markedly dilated and completely occluded by the tumor. Tumor infiltrated into the left upper lobe and mediastinal lymph nodes. The tumor was histologically diagnosed as undifferentiated sarcoma.

[A case of new type scrub typhus (tsutsugamushi disease) presenting with acute respiratory failure and hemophagocytic syndrome]

A 47-year-old male was referred to our hospital with persistent high fever. He had received antibiotics (ASPC) for the diagnosis of acute infectious disease, which failed to respond, and subsequently developed marked lymphocytopenia and thrombocytopenia. During his hospitalization, hypoxic respiratory failure rapidly developed. A bone marrow aspiration revealed marked hemophagocytosis, leading to the tentative diagnosis of opportunistic respiratory infection associated with malignant histiocytosis. Treatment for suspected malignancy and Pneumocystis carinii pneumonia was commenced. However, because of the initial lack of response to ASPC, generalized skin rashes without an ordinary stick wound which had diminished before the hospitalization, and a history of working outdoors in a nearby mountain area, the possibility of new type tsutsugamushi disease was strongly suggested. Intravenous administration of minocycline promptly improved his symptoms and laboratory data. The diagnosis was confirmed by a significant increase in the titer of antibody to Rickettsia tsutsugamushi. The thrombocytopenia was considered to have been caused by co-existent hemophagocytic syndrome.

Dose evaluation and effective dose estimation from CT fluoroscopy-guided lung biopsy

The development of computerized tomography (CT) has made CT fluoroscopy possible with real-time CT images. However examination are expected to have high medical and occupational exposures. Then, exposures to patients and operating and assisting physicians during the CT fluoroscopy-guided lung biopsy were estimated. And changes in the examination conditions to lower the dose were made. Patient exposure was measured using an anthropomorphic phantom by simulation of clinical examination conditions. The surface dose to the physician was measured during actual clinical examinations. The average effective dose for the patient was 34+/-22mSv. The highest surface dose amounted to 1.9 Gy, although this was in a very narrow field. Patient doses could be reduced by a factor of 2.5-3 by changing examination methods while still retaining diagnostic quality. The highest dose to the operating physician was 10mGy which was recorded on the back of the hand and the average effective dose was estimated as 5.99&mgr;Sv per 1-minute examination. Doses were reduced by about a factor of 50 by lowering the tube voltage from 120kV to 80 kV and using a supplementary tool. The doses for assisting physicians were not significant. The exposure for physicians and patients was much affected by lowering the tube voltage used for fluoroscopy. Using a supplementary tool was effective for reducing the dose for physicians.