Bartholomew P. Hsi

Ventilatory functions of normal children and young adults—Mexican-American, white, and black. I. Spirometry

This is a study of the ventilatory functions of 1,805 normal Mexican-American, white, and black students of six public schools in Houston, Texas, with ages ranging from 7 to 20. A roll-seal piston type spirometer was used. The best performed forced vital capacity curve of each student was selected by the computer program from which the following measurements were extracted: FVC, FEV1, FEV1/FVC ratio, PEFR, and MMEF. Each student also had the peak expiratory flow rate measured by the Wright peak flowmeter to establish normal values with this instrument. Significant differences of lung volume and flow rate exist among the three races, and between male and female subjects. Prediction equations and prediction curves for each race and sex are presented. The results of the present study are compared with those of previously published works.

Ventilatory functions of normal children and young adults—Mexican-American, white, and black. II. Wright peak flowmeter

A study was undertaken to establish the normal values of peak expiratory flow rate using the WPFM in three ethnic groups. This report is based on the testing of 1,805 healthy students 7 to 20 years of age in the Houston public schools. Significant differences of WPFR are noted among the three races, and between boys and girls. Prediction equations and regression lines are presented for each sex/race group. The performance of the WPFM is compared with that of the spirometer.

Chronobiometry with pocket calculators and computer systems

SummarySelected methods for the study of biologic time series are reviewed and their relative merits are discussed in the light of underlying assumptions. Their potential applications are exemplified in several fields of biology and medicine. The monitoring of environmental integrity, notably of pollution, is investigated. The need for specifying optimal sampling requirements is underlined. An individualized and time-qualified definition of health by the establishment of reference intervals is required for increasingly rational individualized program for the prevention and/or treatment of disease. With these reference intervals and rhythm characteristics available, one can better interpret with single samples or time series an increased risk of a certain disease or the inception of the disease. For all of these aims the monitoring of environmental and/or personal marker rhythms is essential — to obtain large data bases from which information can be more easily derived for monitoring personal health, to recognize risk as well as to diagnose disease early and to optimize treatment by timing according to rhythms.

Circadian variation in human performance evaluated by the walter reed performance assessment battery

As part of a two clock-time (0830 versus 2030) evaluation of administration-time dependent effects of dexedrine (5 mg) and triazolam (0.25 mg) on human cognitive performance, placebo (control) studies were conducted on 12 diurnally active (0700-2300) male adults (23-38 yrs) using a double-blind, randomized crossover design. Testing was conducted hourly during a series of sleepless 13-hr spans commencing in the morning or evening, using the Walter Reed computer controlled and scored multi-task cognitive performance assessment battery. For the placebo condition, Single and Group Cosinor analyses documented circadian rhythms in performance for most tasks (reaction time, logical reasoning, serial add/subtract and spatial orientation) both for individuals and the group. Overall, performance was worse overnight, when sleepiness was greatest, and best between 1830 and 2030. It was most variable around 0600-0700. The day-night variation in performance over all cognitive tests amounted to 21% of the 24-hr mean.

Stress levels of ambulance paramedics and fire fighters

Responses to Rahe and job stress questionnaires and urinary concentrations of cortisols and catecholamines served to indicate work related stress in 56 fire fighters and 67 paramedics. Although the average Rahe test scores, indicative of stress arising from life events, were comparable, those of the job stress test were statistically significantly higher for the paramedics. The paramedics felt their jobs more exhausting, less satisfying and requiring too much responsibility. For the paramedics, statistically significant higher levels of epinephrine and elevated levels of norepinephrine were found for the work as compared to the off day. For fire fighters, higher levels of cortisol and norepinephrine evident on the off day rather than the work day apparently reflect the relatively light work load experienced during the span of urine collections.

Seasonal Characteristics of and Age at Menarche

Several patterns in menarche are evident over time and across populations which vary by ethnicity, socioeconomic status and altitude of residence: peak occurrence of menarche in January and August with a possible minor peak in April; troughs in the occurrence of menarche to either side of the peak months; and secular trends in season and age patterns of menarche. Contradictory patterns in season of menarche with respect to age at menarche and season of menarche with respect to season of birth are still unresolved. Further research is yet required to evaluate the role of the variety of endogenous and exogenous variables and their interactions on menarche in order to more fully develop an appropriate understanding of the chronobiology of developmental and reproductive phenomena in women and their dependence upon environmental quality and temporal cues.

Multi-chemothermoimmunotherapy for human colon adenocarcinoma in vitro

Effective adjunctive therapies for colorectal carcinoma are clearly needed. We evaluated the cytotoxic responses in vitro of human colon carcinoma cell lines to combined modalities: 5-fluorouracil/leucovorin (5-FU/LV), carboplatin (CP), tumor necrosis factor (TNF) and hyperthermia (HTX). Cytotoxicity was evaluated in a cell proliferation assay using crystal violet staining. 5-FU/LV was administered 2–3 days before TNF and CP, followed 1 h later by HTX. These cell lines were relatively resistant to HTX alone (42°C for 2 h), but were heterogeneous in their responses to various doses of the other single agents. This heterogeneity was also evident for combined modalities: the geneity was also evident for combined modalities: the HCT-15 cell line exhibited significant supra-additivity for selected doses of CP, TNF and 5-FU/LV, which was further enhanced by hyperthermia. In contrast, the HT-29 cell line did not demonstrate a strong pattern for supra-additivity, whereas the DLD-1 cell line had an intermediate response. Thus, our results suggest one approach to develop effective and dose-sparing multimodality therapeutic regimens for colon adenocarcinoma.

A circadian susceptibility/resistance rhythm for potassium cyanide in male BALB/cCr mice.

Circadian rhythms in mortality and/or survival time following a single intraperitoneal injection of a LD50 of potassium cyanide were studied. In two investigations, different but comparable subgroups of inbred male BALB/cCr mice were treated at 4-h intervals (under conditions standardized for chronobiologic study) during 24-h spans. Mice were observed for exact time-to-death during the first hour after treatment as well as overall mortality during the entire 24-h post-injection span following each KCN treatment timepoint. In both studies, mortality from KCN exhibited a 24-h rhythm. Highest mortality occurred in mice injected at 1600 (80% mortality) in Experiment 1 and 2000 (100% mortality) in Experiment II. Lowest mortality occurred at 0400 (40% mortality) in Experiment I and 0800 (30% mortality) in Experiment II. The need to consider the circadian organization of physiologic function when bioassaying toxicity is discussed.

A Modified Play-the-Winner Rule for Sequential Trials

Abstract The two-arm bandit type of Play-the-Winner rule is modified to sample simultaneously the two competing sequences of trials until the first “failure” occurs. Then the sequence without a failure is sampled until it fails, and the process is repeated. This modification leads to the direct application of the sequential probability ratio test on two paired geometric variables. A further modification leads to a scheme which avoids overshooting the stopping boundaries and reduces the total sample size. Exact formulas for the boundary limits, operating characteristics and ASN function for the proposed methods are presented.

A stochastic model of port elevator capacity

Abstract This paper uses the results from a queueing model to optimize the inventory to be held at the port when exporting a bulk commodity.