Lawrence L. Hause

Probability in lymph node sectioning.

The commonly employed methods of sectioning lymph nodes can account for a greater than 30% false pathologic interpretation when studying nodes for the presence of tumor. The failure to identify a tumor within a lymph node is related to the size of the lymph node, size of the lesion, number of sections examined, and the location of the tumor within the node. Analysis of these variables is approached by applying mathematical and computer formulation to numerous model nodes containing lesions of variable size and location. The percentage probabilities of identifying various sized lesions in different sized nodes is calculated in graphic form. These studies propose a functional method of lymph node sectioning which is applicable to improved sectioning technique.

Electrode and Electrolyte Impedance in the Detection of Bacterial Growth

The growth of bacteria in culture was found to produce impedance changes between two metal electrodes which result from changes both in conductivity and electrode impedance. Predominant changes were found in the imaginary impedance component at low frequency. Linear ac impedance characteristics were found in the relation between real and imaginary impedance components before and during bacterial growth. This linear relation is consistent with characteristics of diffusion and electron exchange (oxidation-reduction) at the electrode. The measurement of impedance in this system was limited below 100 Hz by nonlinearity in the voltage-current relation. Bacterial growth was best detected with stainless steel electrodes at low frequency (100 Hz) and including the imaginary component of impedance.

Correlation of neuronal cell body size in motor cortex and hippocampus with body height, body weight, and axonal length

This study examined the comparative effects of body height and body weight on the neuronal cell size in humans and investigated their possible mechanisms. A total of 21 cases between the ages of 20 and 40 years were studied. Data on body height, body weight, and neuropathology were obtained from autopsy records. Mean cross sectional areas of cell bodies for 30 normal neurons were determined for the motor cortex projecting to lumbar spinal cord segments (L) 1-4 (Betz cells) as well as various regions of the hippocampus. Approximate axonal length of the motor neuron studied was measured from motor cortex to L2. We found that only motor cortex neuronal cell body size was significantly proportional to body height and the respective axonal length (p < .05). The findings indicate that: 1) body height has a greater effect than body weight on the motor neuron cell size, probably because of its association with axonal length; 2) the effect is regional (motor cortex) rather than general.

The determination of the eosinophil count: Comparison of two techniques

The total eosinophil count obtained by use of the standard hemacytometer is considered by several investigators to be the most reliable method for the determination of the circulating eosinophil levels in the blood because it is believed to be less subject to error than the calculated eosinophil count obtained with Wright stained blood smears from the differential count. We compared the two techniques in outpatients as well as inpatients with and without allergies (total of 514 patients). Our results demonstrate that the eosinophil count by the two methods are similar.

Microscopic image analysis in a diagnostic system for Alzheimer's disease

Microscopic image analysis (MIA) is used to measure quantitatively the features of pyramidal neurons, dentate neurons and amyloid plaques in the hippocampus of postmortem brains from individuals with Alzheimers disease (AD) and normal controls. The average area and optical density, which is proportional to nucleic acid content, of AD neurons are equal to or greater than those of normal neurons. These increases remain to be explained. Plaques are also greater in size and in number for AD. A diagnostic and grading system for AD is proposed on the basis of these quantitative features.<<ETX>>

A platelet aggregating factor in thrombotic thrombocytopenic purpura: initial activity, fluctuations, and removal by plasma exchange

A factor capable of aggregating normal platelets was found in the plasma of six consecutive patients with thrombotic thrombocytopenic purpura (TTP). The activity of the aggregating factor in whole plasma, the cold protein fraction from plasma and the residual supernatant was monitored during each patients course of therapeutic plasma exchange. Although two patients demonstrated the highest level of aggregating activity at the time of diagnosis, the level fluctuated in five of six patients. Increasing levels of activity were usually accompanied by signs of clinical deterioration. Activity repeatedly within the normal range was not seen until remission of the syndrome. Neutralization of the aggregating activity in vivo through removal of patient plasma and replacement with fresh frozen plasma (plasma exchange) was accomplished less readily and less predictably than by mixing patient plasma and normal plasma in vitro. Use of the aggregating factor level in evaluating the need of plasma exchange is discussed.

Correlation of perinatal brain growth with age, body size, sex, and race.

This study compares the weight of the human brain to gestational age and body dimensions. A new formula for calculating the rate of growth is proposed. It consists of a second order polynomial function: Y = A0 + A1X + A2X2, in which Y is brain weight, body weight, height, or body surface area; X is gestational age in weeks and A0, A1, and A2 are statistically estimated coefficients. In utero, the growth rate is most rapid for body weight, followed in decreasing order by brain weight, body surface area, and height. Brain growth is the same for both sexes in black and white races; it accelerates between the 20th and 45th weeks of gestation. The size of the newborn infant brain is directly related to gestational age and body size and is not determined by sex or race.

A Method for the Preparation of Platelets for Transmission Electron Microscopy

A modified method for the preparation of platelets for transmission electron microscopy has been developed. A suspension of platelets in plasma is fixed in glutaraldehyde, immobilized in agarose, and further fixed in osmium tetroxide. The specimen is then dehydrated with alcohol and embedded in Spurr. The key point of this method is the immobilization of the platelet pellet in agarose gel, thus dispensing with the difficulties associated with excessive centrifugation and resuspension of the platelets. Platelets prepared for transmission electron microscopy by this method show excellent preservation of ultrastructure. In addition, this method is relatively rapid, requiring only one day for processing the specimen.

Rapid determination of the rate constant of agonist-induced association of single platelets

We have developed a rapid and convenient method for determining the rate constant of association of single platelets. Using the concentration of single platelets prior to activation and that 0.25 min (15 s) after activation, this rate constant can be determined accurately without concern for reversibility of the aggregation process or need for statistical analysis. A linear relationship between initial platelet concentration and the rate constant of association is defined. The clinical utility of this association parameter is discussed.

Impedance measurements during simulated blood flow

It is determined how impedance is affected by hematocrit, conductivity and electrode configuration in a continuous flow system in vitro. Four-electrode measurements have robust characteristics which require constant geometry but do not require uniform fields or rigid positioning. Findings show that the ratio of red blood cell conductivity to electrolyte conductivity is important in the pattern impedance versus hematocrit.<<ETX>>