Development of a solid-phase extraction technique for alpha-human atrial natriuretic peptide in human plasma

A reliable extraction method was developed for alpha-human atrial natriuretic peptide (alpha-hANP) using Bond Elut C8 columns in tandem. This involved activation of the columns using methanol followed by a water wash to remove the excess methanol. Plasma (1 ml) was then added and a vacuum applied until all was drawn through. Excess protein and other endogenous compounds were removed by washing the columns with water and elution of the alpha-hANP was achieved with 0.75 ml acetonitrile-water-trifluoroacetic acid (80:19.8:0.2, v/v/v). Samples were evaporated under nitrogen and reconstituted in radioimmunoassay buffer ready for analysis. The recovery of alpha-hANP from plasma using this method was found to be 90% +/- 0.6% [mean +/- standard error of the mean (S.E.M.); coefficient of variation (C.V.) = 1.5%] which will allow more precise measurement of the peptide than is presently available. With this high precision of analysis available, having a limit of detection of 0.4 fmol/ml and a range of 0 to 32 fmol/ml, a low-dose infusion of alpha-hANP was conducted and the changes in plasma concentration were followed.

Abnormal polyamine metabolism in hypertensive cardiac hypertrophy

In order to assess myocardial hypertrophic activity during the process of hypertensive cardiac hypertrophy in the presence and absence of treatment with anti-hypertensive agents, we analyzed myocardial polyamine concentrations in spontaneous hypertensive (SHR) rats and control rats of Wistar Kyoto (WKY) strain. The anti-hypertensive agents studied were diltiazem, hydralazine and captopril, each of which was administered for 5 weeks. In comparison with WKY rats, SHR rats showed elevated blood pressure and enlarged hearts with higher myocardial spermidine concentration. Although blood pressure was lowered in the diltiazem-treated SHR rats, heart weight and myocardial spermidine concentration increased as in untreated SHR rats. In the hydralazine-treated group increases in both blood pressure and myocardial spermidine concentration were suppressed, while an increase in heart weight was not. In the captopril-treated group, increases in blood pressure, heart weight and spermidine concentration were all suppressed. Since spermidine level appears to be a sensitive indicator of hypertrophic activity in the heart, this study suggests that captopril exerts an inhibitory effect on hypertensive cardiac hypertrophy whereas diltiazem does not. It also suggests that hypertrophy may reach a certain plateau level earlier in the hydralazine-treated animals than in others.

Disposition and metabolism of indeloxazine hydrochloride, a cerebral activator, in rats

1. The disposition and metabolism of indeloxazine hydrochloride ((+/-)-2-[(inden-7-yloxy)methyl]morpholine hydrochloride) were studied in male Sprague-Dawley rats. 2. After oral administration of 14C-indeloxazine hydrochloride, the plasma concentration of total radioactivity reached a maximum at 15 min and declined with an apparent half-life of 2.2 h in the first 6 h period and declined more slowly thereafter. Unchanged drug in the plasma represented 13.5%, 5.9% and 0.4% of the total radioactivity at 15 min, 1 h and 6 h respectively after administration and levels decayed with a half-life of 0.9 h. 3. After oral and i.v. administration of the labelled compound, the urinary and faecal excretion of radioactivity in 72 h were 61-65% and 31-36% of the dose, respectively. Biliary excretion in bile duct-cannulated animals amounted to 49% of the dose in 72 h. 4. Seven metabolites have been isolated from the plasma or urine and characterized by i.r., n.m.r. and mass spectrometry. They were derived through dihydrodiol formation in the indene ring, hydroxylation of the indene ring and N-acetylation, oxidation and oxidative degradation of the morpholine ring. Some metabolites were excreted as their glucuronic acid or glucose conjugates. The major metabolite appeared to the trans-indandiol analogue of indeloxazine. 5. Possible metabolic pathways of degradation of the morpholine ring are discussed.

Clinical application of extracorporeal shock wave lithotripsy using microexplosions

Extracorporeal stone disintegration using a chemical explosive (10 mg. lead azide) as an energy source of underwater shock waves was performed in 105 patients 11 to 72 years old who had stones in the upper urinary tract. We used a prototype disintegrator in this series. The over-all rate free of stones 3 months after treatment was 82 per cent. Shock wave therapy was performed alone in 77 patients (73 per cent), while the remainder required combined treatment with percutaneous and/or transurethral lithotripsy. The most common complications were colic pain (30 per cent) and fever (23 per cent). In 4 patients other complications, that is bacteremia, gastrointestinal bleeding, ureteral injury and subcapsular renal hematoma, were observed but they were treated conservatively with no serious adverse effects. Our study demonstrates the safe use of this method for clinical treatment.

Cardiorespiratory arrest in a patient with advanced diabetic autonomic neuropathy

A 53-year-old diabetic woman who had been diabetic for 14 years had recurrent episodes of cardiorespiratory arrest, which were easily resuscitated by a few chest massages. In 2 of 4 episodes a radial pulse was detected, so respiratory arrest was thought to be a primary event. Pentazocine was injected several hours prior to each of the 3 episodes. This was considered to be a precipitating factor. From the first episode of cardiorespiratory arrest, she received oxygen inhalation. When oxygen inhalation was withdrawn for 5-10 min, she became cyanotic. This was considered to be a sign of lack of hypoxic drive mediated by peripheral chemoreceptors. Ventilatory responses to hypercapnia was markedly decreased, indicating impaired central chemosensitivity. The possibility that impaired chemosensitivity could be a cause of respiratory arrest was suggested.

[Clinical investigation of cefotiam in combination with aminoglycoside or (and) penicillin against complicated infections with hematopoietic disorders]

Clinical investigation of combination use of cefotiam (CTM), aminoglycoside, or (and) penicillin against complicated infections with hematopoietic disorders was performed, and the results were as follows. Fifty-one patients were administered CTM in combination with aminoglycoside or (and) penicillin. The clinical response was excellent 19.6%, good 27.4%, fair 21.6%, and poor 31.4% showing efficacy rate of 47.1%. The combined therapy of CTM and aminoglycoside was clinical effective in 70% of 10 patients with complicated sepsis. Therefore, combination use of CTM and aminoglycoside is considered to be the first choice for the treatment of complicated sepsis with hematopoietic disorders. The clinical effectiveness of CTM was not influenced by the number of mature neutrophil at the first phase of CTM treatment, but was influenced at the end phase of CTM treatment. Gram-negative bacilli were dominantly isolated from the patients. Pseudomonas sp. was isolated from 70% of the patients with sepsis. No remarkable side effects were observed in this investigation.

Computed tomography and composition of renal calculi

The attenuation values of computed tomography were studied in 50 recovered renal calculi of more than 10 mm in diameter, in the hope of determining the composition of calculi in situ. The attenuation value of various calculi (mean +/- s.d.) in a 5 mm slice with a maximal rectangular region of interest was as follows (Hounsfield units); mixed calcium oxalate and phosphate 1,555 +/- 193 (n = 22), magnesium ammonium phosphate 1,285 +/- 284 (n = 18), calcium oxalate 1,690 (n = 1), calcium phosphate 1,400 (n = 2), cystine 757 +/- 114 (n = 5) and uric acid 480 (n = 2). Attenuation values ranging from 500 to 1,600 overlapped for various calculi, except those composed of uric acid calculi. There was no correlation between the attenuation value and the mineral content such as calcium or magnesium per unit weight of calculus. The mineral content per unit volume seemed to be attributable to the attenuation value. From the present results we conclude that the determination of calculous composition by the attenuation value is possible only for oxalate calculi of more than 1,600 and uric acid calculi of less than 500 attenuation value, provided that the proper CT slice location, the region of interest and the appropriate calculus size can be determined.

Clinical usefulness of artificial endocrine pancreas "Biostator" in management of unstable diabetics

The diurnal blood glucose profiles of 15 unstable diabetics were continuously monitored by the artificial endocrine pancreas (AEP, Biostator). Then, feedback control (FC) with the AEP was performed on each subject for 24-32 hr. Based on the data obtained from FC, the patients received an intensified conventional insulin therapy (ICIT) consisting of two daily mixed injections, 45-60 min prior to meals. There was a negative correlation between the MAGE and the sum of serum CPR in a 50 g OGTT, before FC. The M-value, MBG and MAGE decreased significantly during FC and remained lower one month later, compared with those values obtained before FC. The ICIT caused a noticeable decrease in HbA1 levels one to four months after FC. The ICIT was characterized by an increase in the proportion of short-acting insulin in the daily insulin dosage to 40. 3 +/- 11.5%. The proportion of daily insulin dosage to body weight also increased to 0.73 +/- 0.17 U/kg. These results suggest that the AEP, Biostator, could be useful in the clinical management of unstable diabetics by providing a more precise estimate of patients insulin requirements, especially those of short-acting insulin, leading to a better long-term control of blood glucose.

A critical level of diabetic autonomic neuropathy

Diabetic autonomic neuropathy was expressed quantitatively using the coefficient of variation of R-R intervals (CVR-R) in ECG and its critical level where diabetics were plagued with various symptoms was investigated. The subjects were 58 diabetics under the age of 40 years. ECGs were recorded in the resting supine position and the degree of autonomic neuropathy was expressed as CVR-R by processing 100 consecutive R-R intervals. Symptoms caused by diabetic autonomic neuropathy were determined using a questionnaire. CVR-R were 1.10 +/- 0.34% (mean +/- SD) and 4.31 +/- 2.01% in patients with and without orthostatic hypotension respectively, the former being significantly lower. CVR-R were 1.30 +/- 0.88% and 3.81 +/- 1.31% in those with and without impotence respectively, the former being significantly lower. CVR-R were 0.80 +/- 0.14% and 3.85 +/- 2.17% in those with and without diabetic diarrhea respectively, the former being significantly lower. Concerning sweating abnormality CVR-R were significantly reduced in subjects exhibiting gustatory sweating (1.52 +/- 0.74%) and hypohidrosis (2.26 +/- 1.44%) when compared to those without these symptoms. From the results obtained, a CVR-R of 2% can be considered as the critical level which determines whether symptoms due to diabetic autonomic neuropathy will appear or not.

Chemosensitivity in patients with diabetic neuropathy

1. By using the rebreathing method, ventilatory responses to inhaled CO2 were studied in patients with diabetic neuropathy. 2 Their general respiratory functions including vital capacity (VC) and forced expiratory volume in 1 s (FEV 1.0) were within normal ranges and ventilatory responses to CO2 in the range 5.32--5.99 kPa were not significantly different between patients and normal subjects. However, ventilation in the patients was significantly less than that in normal subjects when the alveolar partial pressure of CO2 (PACO2) was above 6.65 kPa. 3. The slope of the CO2 response curves obtained during hyperoxic rebreathing was significantly less in the patients than in the normal subjects. In the patients CO2 response curves with 15% (v/v) O2 were either the same or had lower slopes than those measured with 100% O2. 4. The results suggest that both peripheral and central chemosensitivity, including the activity of the respiratory centre, are reduced in patients with diabetic neuropathy.

Role of acetaldehyde in the pathogenesis of alcoholic cardiomyopathy

Rats given both ethanol and tolbutamide showed decreased oxidative phosphorylation of the myocardial mitochondria as compared with rats given only ethanol. There were no differences in ethanol consumption and blood ethanol levels between the two groups. The concentration of acetaldehyde tended to be higher in rats given both ethanol and tolbutamide than in rats given ethanol alone. It is concluded that acetaldehyde plays a more important role in the production of alcoholic cardiomyopathy than does ethanol itself.