Carotid body chemoreceptor and ventilatory responses to sustained hypoxia and hypercapnia in the cat

To understand the role of carotid chemoreceptor activity in the ventilatory responses to sustained hypoxia (30 min) the following measurements were made in cats anesthetized with alpha-chloralose: (1) carotid chemoreceptor and ventilatory responses to isocapnic hypoxia and to hypercapnia during hyperoxia; (2) carotid chemoreceptor responses to isocapnic hypoxia after dopamine receptor blockade; and (3) ventilatory responses to hypoxia after bilateral section of carotid sinus nerves (CSN). Transition to hypoxia (PaO2 approximately equal to 52 Torr) from hyperoxia gradually increased carotid chemoreceptor activity by ten fold and ventilation by two fold without any detectable overshoot. Termination of isocapnic hypoxia with hyperoxia (PaO2 greater than 300 Torr) at 30 min promptly restored the carotid chemoreceptor activity to prehypoxic level. Ventilation also decreased promptly, but remained above the control value. Induction of hypercapnia (from 31.8 Torr to 43.9 Torr) during hyperoxia was followed by a prompt increase in the chemoreceptor activity by four fold which subsequently diminished, and by a gradual four fold increase in ventilation. Termination of hypercapnia after 30 min was followed by a prompt return of chemoreceptor activity and by a slow return of ventilation to near control levels. Dopamine receptor blockade increased carotid chemoreceptor responsiveness to acute hypoxia but did not alter the response pattern during sustained hypoxia. After bilateral CSN section, ventilation decreased during maintained hypoxia. Thus, a stimulatory peripheral and inhibitory central effects of hypoxia could produce a biphasic ventilatory response to short-term hypoxia in the anesthetized cat with intact CSN but did not manifest it. The results suggest that the chemosensory input not only promptly stimulates ventilation but also prevents the subsequent depressant effect of hypoxia on the brain-stem respiratory mechanisms and hence presumably a biphasic ventilatory response in the anesthetized cat.     

Hemostatic alterations in beta-thalassemia/hemoglobin E patients

To search for evidence of coagulation activation ex vivo, the levels of human prothrombin fragment 1+2 (F1+2) were examined in 69 beta-thalassemia/Hb E patients. Levels of protein C inhibitor (PCI) and activated protein C - PCI (APC:PCI) complex were also determined in 9 of the above patients in conjunction with protein C (PC) antigen and activity, in an attempt to detect increased consumption of PC. In mean level of F1+2, there was a statistically significant difference between normal control and post-splenectomized patients (p < 0.05) but not between normal control and non-splenectomized patients (p > 0.05). The mean levels of PC activity and PC antigen in the patients were much lower than in normal controls. However, the mean levels of PCI and the mean level of APC:PCI complex in the patients were not significantly different from those in normal controls (p > 0.05). The high level of F1+2 in post-splenectomized patients found in this study agreed well with clinical and other laboratory findings. The normal level of PC inhibitor and APC:PCI complex found in this study provided no evidence of increased consumption of protein C in thalassemia patients.     

Hydrogenation of quinone compounds during secondary ion mass spectra measurement

Antibiotics containing a quinone group show characteristic reduced pseudo-molecular ions (M + 2)+ and (M + 3)+ during the measurements of secondary ion mass spectra using glycerol as a matrix. The ratios of peak intensities (M + 2)+ and (M + 3)+ over (M + 1)+ increase with time. As this phenomenon is not found using sulfolane as a matrix, the quinone group seems to be hydrogenated to a hydroquinone by active hydrogen which is produced from a free hydroxyl group of the glycerol by bombardment with the Xe+ beam. This hydrogenation reaction is specific for the quinone group.     

Natural course of HGV infection in haemophiliacs

The natural course of hepatitis G virus (HGV) infection was clarified in 70 haemophiliacs by testing for HGV RNA and antibodies against HGV envelope protein (anti-E2). None of 12 patients treated with only virus-inactivated coagulation factors were infected with HGV. Of 58 patients who received non-inactivated products, 28 (48%) were positive for HGV RNA and/or anti-E2. Of 16 patients with anti-E2, 14 were negative for the viral RNA, and had recovered from HGV infections. HCV antibodies were detected in 59 patients, and eight patients were successively negative for HCV RNA. Thus, the recovery rate of HGV infection (14/28, 50%) was higher than that of HCV (8/59, 14%) ( P  < 0.001). Longitudinal study revealed that anti-E2 developed either during viraemia or some years after seronegativity for HGV RNA. Hence the antibody response itself seemed not to play a major role in the clearance of HGV, though anti-E2 was associated with the clearance of HGV RNA. In conclusion, HGV and HCV are prevalent in patients treated with unsterilized coagulation factor concentrates. However, in contrast to HCV, spontaneous recovery is frequently observed in HGV infections.     

Studies on acetylspiramycin. 1. Separation and chemical structures of acetylspiramycin components

1. A macrolide antibiotic acetylspiramycin (ASPM) was separated into seven fractions using high performance liquid chromatography (HPLC) with Lichrosorb RP-8 and mobile phase of a mixed solvent of 0.025M phosphate ammonium (pH 7.4) and acetonitrile at a ratio of 10:18. 2. Five components were purified over 90%, and analyzed using mass spectroscopy, 1H NMR, and 13C NMR, and their chemical structures were determined as 4'-acetylspiramycin I, 4'-acetylspiramycin II, 4'-acetylspiramycin III, 3',4'-diacetylspiramycin II and 3',4'-diacetylspiramycin III, respectively. 3. The weight component ratio of the seven fractions of ASPM separated by HPLC was constant throughout several lots of ASPM which had been stocked for nearly 15 years at room temperature, indicating an excellent chemical stability of the antibiotic. 4. Some physicochemical parameters were determined for the five ASPM components. Solubilities in water at 24 degrees C were in a range from 0.14 mg/ml to 4.9 mg/ml, and they were, in the decreasing order, 3',4'-diacetylspiramycin III, 3',4'-diacetylspiramycin I 4'-acetylspiramycin III, 4'-acetylspiramycin II, and 4'-acetylspiramycin I. Relationships between solubilities and numbers and positions of acyl substituents in spiramycin molecule are discussed.     

Diagnosis of DIC in newborn infants

Disseminated intravascular coagulation (DIC) occurs most frequently during the newborn period. Some clinical and laboratory criteria are available for the diagnosis of DIC in adults. However, they are not necessarily applicable in the diagnosis of DIC in newborn infants since the physiological state of coagulation during the newborn period differs from that in adults. We therefore reviewed 74 cases of DIC in newborns, including 34 cases at our own newborn care units. Criteria for the diagnosis of DIC in newborn infants were established.     

Benefits and problems of home infusion therapy]

A survey was performed to clarify the benefits and problems of home infusion therapy because 8 years had passed since this type of treatment was officially approved in Japan. Questionnaires were sent to hemophiliacs and the physicians in charge of hemophiliacs in the Kyushu district. The main results obtained from analysis of responses concerning 197 patients were as follows. 1) Out of 197, 140 patients were on home therapy programs. 2) The number of bleeding episodes was increased in 6.8%, decreased in 51.1% and unchanged in 42.1% of patients after the start of home infusion therapy programs. 3) The severity of bleeding symptoms was reduced in 92.9% of patients after the start of these programs. 4) After the start of home infusion therapy programs, the amount of blood products administered increased in 24.4%, decreased in 20.6% and was unchanged in 55.0%. 5) Complications such as abdominal pain, headache, ulticaria, itching, shivering, fever and discomfort were reported from 19 hemophiliacs. Only one of them visited the hospital due to severe abdominal pain which appeared immediately after home infusion of blood product. 6) It was indicated that better education or re-education of home infusion therapy is necessary for hemophiliacs and/or their families who are on home infusion therapy programs, because half of them had not received proper education concerning home infusion.