Characteristics of laser Doppler flowmeters with differing optical arrangements.

Recently, various laser Doppler flowmeter (LDF) systems have been used for evaluation of tissue microcirculation. However, indifference has often been shown by doctors and researchers regarding their sampling volume, stability and accuracy, which differ with various optical arrangements. In this study we evaluated the characteristics of three LDF systems with different optical arrangements. The sampling depths in both blood and tissue were found to differ with the different optical arrangements, although the laser power emitted from the probes is nearly equivalent. Each depth significantly changed at haematocrits between 5.0 and 36.5%. The stability and the accuracy of the measurements also differed. In the practical case of tissue microcirculation it is important to measure blood flow with an understanding of the material differences in the characteristics of the LDF systems.     

Mass-screening for acid mucopolysaccharidosis using urine samples by modified HCl-albumin turbidity method

To establish a method for screening acid mucopolysaccharidosis (AMPS), the HCl-albumin turbidity method was reexamined and modified for semiquantitative analysis. Mucopolysaccharide samples and HCl-albumin in buffer solution were incubated at 37 degrees C for 30 minutes, and the optical density at 600 nm (OD 600) of the reaction mixtures were measured. When the same amount of the samples were tested, OD 600 of dermatan sulfate and hyaluronic acid were higher than that of keratan sulfate. When the cut-off point of OD 600 was set at 0.100 based on the values obtained from randomly selected subjects, only 3 of 328 urine samples (0.9%) showed value higher than the cut off value. The values in five patients with AMPS were all above 0.800 without overlapping those of the control subjects. These results suggest that mass-screening for AMPS using urine sample is possible by the partially modified HCl-albumin turbidity method with the cut-off point of OD 600 set at 0.100.     

A neuropathological analysis of neonatal deaths over a 20-year period]

This study is an overview of 2,515 consecutive autopsies on newborn infants who died during the first 28 days of life at the Hospital for Sick Children, Toronto, during the period 1970-1989. The infants were grouped into 2 categories according to their gestational age and then subdivided into the groups of early (0-6 days) and late (7-28 days) neonatal deaths. In this overview trends in the occurrence of neuropathological observation were documented. In each 5-year time period and each gestational group the following diagnoses were recorded; hypoxic-ischemic neuronal changes, periventricular leukomalacia, infarction, kernicterus, meningitis, and hemorrhage (subependymal, parenchymal, choroidal). In these 20 years, the mortality in preterm infants has decreased due to a fall in the incidence of subependymal/intraventricular hemorrhage, kernicterus and meningitis. In contrast, the rate of mortality in term infants has increased due to a higher frequency of hypoxic-ischemic neuronal necrosis and choroid plexus hemorrhage.     

Relationship between the direction of mandibular growth and masseter muscle conduction velocity.

INTRODUCTION: The purpose of this study was to investigate the relationship between muscle conduction velocity (MCV) of the masseter muscle and the direction of mandibular growth. METHODS: Longitudinal cephalometric X-rays taken at the prepubertal and postpubertal periods of 16 Japanese girls were analyzed. MCV was calculated from the delay in myoelectric signals obtained by using multiple surface electrode arrays placed along the fibers of the left masseter muscle in the postpubertal period. The direction of mandibular growth was evaluated by superimposition of the lateral cephalometric X-rays at the prepubertal and postpubertal periods. The relationship between MCV and the direction of mandibular growth was analyzed statistically. RESULTS: MCV was significantly correlated with the vertical facial height at the postpubertal period and the direction of mandibular condyle growth. CONCLUSIONS: If the relationship between prepubertal and postpubertal of MCV is clarified, it might be possible to predict the direction of mandibular growth and the vertical facial proportions at the postpubertal period from MCV of the masseter muscle at the prepubertal period.     

Flow- and pressure-adapted portal arterialization in dogs

The effects of portal arterialization after portacaval shunt were studied in dogs. Flow- and pressure-adapted portal arterialization was performed by mounting a Teflon cuff on an autogenous vein bypass graft between the hepatic stump of the portal vein and the right renal artery. Immediately following operation, the total hepatic blood flow and intrahepatic portal venous pressure were within normal range. Eight weeks after operation, the intrahepatic portal venous pressure remained within the preoperative range, while total hepatic blood flow had increased double or triple. However, structual change due to increased flow was absent in the liver, even sixteen months after operation. Body weight, liver enzyme chemistry, ICG clearance rate, and amino acid metabolism were well maintained for the entire period of investigation. These findings suggest that sequelae such as hepatic encephalopathy and impaired hepatic metabolism after portacaval shunt can be avoided by portal arterialization, in the presence of an appropriate flow and pressure.     

Relationship between periventricular hemorrhage, leukomalacia and brainstem lesions in prematurely born infants

The brain pathology in very prematurely born infants with intraventricular hemorrhage (IVH) was studied particularly as to the severity and site of the complicated brain lesions responsible for the prognosis. A high frequency of leukomalacia, pontosubicular necrosis and/or olivocerebellar neuronal loss was found in the cases of IVH, and these non-hemorrhagic brain lesions showed an increasing frequency with the grade of IVH. However, there was marked reduction of IVH, periventricular leukomalacia and, in particular, brainstem lesions in prematurely born cases of sudden infant death. These IVH and associated conditions have different pathogenesis, but factors responsible for their occurrence may be present together in each case.