Low Pressure Group Research Articles

Prognostic Value of Urodynamic Testing in Myelodysplastic Patients

We herein describe the clinical progress of 42 myelodysplastic patients studied urodynamically and followed for a mean of 7.1 years. Urodynamic evaluation included urethral pressure profilometry, simultaneous determination of urethral pressure, intravesical pressure and external anal or external urethral sphincter electromyography with fluoroscopic voiding cystourethrography. Assessment of urethral function showed 36 patients (86 per cent) with an open vesical outlet and nonfunctional proximal urethra. Cystometrography revealed that 7 of 42 patients (17 per cent) had reflex detrusor activity: 4 with coordinated micturition and 3 with detrusor-sphincter dyssynergia. Thirty-five patients (83 per cent) had areflexic detrusor dysfunction: 5 with atonic detrusor response and 30 with a progressive increase in pressure with increasing volume. The intravesical pressure at the time of urethral leakage was 40cm. water or less in 20 patients and at pressures greater than this value in 22 patients. No patient in the low pressure group had vesicoureteral reflux and only 2 showed ureteral dilatation on excretory urography. In contrast, of the patients in the higher pressure group 15 (68 per cent) showed vesicoureteral reflux and 18 (81 per cent) showed ureteral dilatation on excretory urography. Thus, a striking relationship between the urethral closure pressure and intravesical pressure at the time of urethral leakage and the clinical course in this group of myelodysplastic patients is demonstrated. Every patient with a normally closed vesical outlet was continent on intermittent catheterization and an anticholinergic agent, while only 60 per cent of patients with open bladder outlets similarly treated achieved good urinary control and none was dry. An artificial sphincter device would seem to be a reasonable method to achieve urinary control in the latter patients but the detrusor response to filling also must be considered. Detrusor hypertonia should be controlled or controllable before a sphincter augmenting device can be used safely. Treatment options for patients with high urethral closure pressures include intermittent catheterization and anticholinergic medications or a sphincter ablative procedure to decrease the outlet resistance combined with anticholinergic therapy and implantation of an artificial sphincter. However, only longer followup will determine if these therapeutic regimens will prevent upper urinary tract deterioration.

Fatty acid in cerebrospinal fluid of congenital hydrocephalus.

In this presentation the analysis of fatty acid composition in cerebrospinal fluid (CSF), by gas-chromatography, in 40 cases of congenital hydrocephalus before and after shunting operation is discussed. Each fatty acid content was determined by the method which uses arachidic acid as an indicator. The total fatty acid value was found to be significantly higher than normal in the preoperative period in hydrocephalus. The concentration of the total and of the short chain fatty acids (less than C16) in the CSF was higher in the high ventricular CSF pressure group of hydrocephalic patients (above 150 mm H2O) than in the low pressure group. The concentration level of all these fatty acids in the CSF was higher in the cases showing poor prognosis than in those with good prognosis 3 weeks after operation.

Comparison of low and standard pressure gas injection at abdominal cavity on postoperative nausea and vomiting in laparoscopic cholecystectomy.

Background and Objective: Postoperative nausea and vomiting (PONV) is the main concern for 40-70% of patients undergoing laparoscopic cholecystectomy. Our objective was to compare carbon dioxide gas at low pressure and standard pressure for the occurrence of PONV on patients undergoing laparoscopic cholecystectomy. Methods: This double- blind trial was conducted on 50 women patients aged between 18 to 60 years with acute cholecystectomy. The patients were divided into two groups: low pressure (LP) (received LP gas, 7-9 mmHg) and standard pressure (SP) (received SP gas, 14-15 mmHg). Nausea and vomiting in patients at hours 0-4, 4-8, 8-12, 12-24 after the surgery were recorded. Results: The frequency of PONV in the LP and SP groups did not demonstrate statistically significant different (P > 0.05). Nevertheless the frequency of shoulder pain after 4 hours at the LP group compared with SP group was significantly different (P < 0.023). Conclusions: The use of low pressure gas compared to standard pressure gas to create pneumoperitoneum could not reduce the PONV whereas the frequency of shoulder pain in LP group was reduced. Low pressure gas was associated with reduction of surgeon visibility and subsequently more prolonged surgery duration.

On the cause of the preferential distribution of certain metamorphic minerals in orogenic belts of different age

Almost all glaucophane and all lawsonite seem to have been formed by post-Palaeozoic regional metamorphism. Moreover, according toMiyashiro regional metamorphism of his kyanite-sillimanite type (= Dalradian or Barrovian type) was common in Palaeozoic time, whereas that of his andalusite-sillimanite type and low-pressure intermediate group (Buchan type) took place in orogenic belts of Precambrian as well as Palaeozoic and Mesozoic age.

PHYSIOLOGICAL INTERPRETATION OF THE PLAIN RADIOGRAPH IN MITRAL STENOSIS, INCLUDING A REVIEW OF CRITERIA FOR THE RADIOLOGICAL ESTIMATION OF PULMONARY ARTERIAL AND VENOUS PRESSURES.

1. An assessment of the accuracy of different groups of criteria for estimating pulmonary arterial and venous pressures from the plain radiograph in mitral stenosis has been made. 2. The degree of pulmonary vascular resistance has been related to the radiological appearances of the lung fields. 3. The relationship of “B” lines to pulmonary arterial and venous pressure has been studied. 4. Evidence supporting Simon's (1958) hypothesis of high and low pressure groups in venous hypertension is advanced and appropriate pressure ranges suggested for each of the six grades. 5. A set of diagrams for assessing pulmonary artery and pulmonary venous pressure from the plain radiograph in mitral stenosis has been presented.

THE EFFECT OF HIGHVERSUS LOW PRESSURE ON THE PNEUMATIZATION OF THE MASTOID CELLS AN EXPERIMENTAL STUDY

It is generally- recognized that the extent of pneumatization of the mastoid cells may be genetically determined. On the other hand, otitis in infancy has been considered an inportant factor associated with underdeveloped mastoid cells. The author and T. Goto do not agree with this opinion and have believed that the development of the mastoid cells may be genetically determined.Recently T. Goto and S. Shibata have reported that there is a marked fibrosis in the lungs of skin divers and limited development of the mastoid cells. From these results they suspected that pressure might have some influence on the extent of pneumatization of the pneumatic cavities, the lungs, accessory sinuses and mastoid cells.The author has planned to study experimentally the effect of pressure upon the mastoid cells.For this experiment he constructed a pressure tank, in which constant pressure could be maintained at 3 atmospheres or at a pressure of 2/5 of an atmosphere. The oxygen was insufflated into the tank under constant pressure.The animals used for this experiment were young chickens 7 days old at the start of the experiment. The chicken has well-developed mastoid cells and its mastoid cells develope very quickly. The experiment was carried out on the two main groups, namely the high pressure group and the low pressure group. Chickens in each of the groups were placed in the tank for 2 hours daily. In each of these groups the observation was made at the end of 30 and 60 days on 15 chickens in each subgroup. During these experiments chickens have not shown any gross changes. The development of the chickens was not delayed compared with the control chickens.But the mastoid cells of each group were markedly underdeneloped. The septae of the air cells were thickend and the lumen of the-cells were decreased in size. The bight of the linning epithelial cells was increased and the subepithelial tissue was fibrous and thick. Residual cartilage tisstue was found. The microscopic appearance of the air cells in chickens exposed for 60 days to high and low pressures are similar. The normal process of development, in which leucocytes infiltrate the subepithelial tissue, macropgages cause bony resorption, and the epithelium proliferates causing an increase in pneumatization, is delayed.These findings indicate a delay in the development of the mastoid cells. The findings in the mastoid cells of chickens in the two groups were similar, whether they exposed to positive pressures or negative pressures. The animals exposed for the longer time period (60 days) revealed only a slightly increased limitation in the development of the development of the mastoid cells than seen at the end of 30 days.