Agreement of activity monitors for assessment of patients with sub-acute stroke in an inpatient rehabilitation facility

PURPOSE

Determine the level of agreement of three activity monitors compared with the gold standard (video review) on the activity level of patients with stroke.

METHODS

A prospective, observational, agreement study was performed on 47 individuals with sub-acute stroke in an inpatient rehabilitation facility. Data was collected during one physical therapy session. Individuals wore three device types; Actigraph (AG), Activpal (AP), and stepwatch activity monitor (SAM). Variables assessed were step counts for each limb (hemiparetic and non-hemiparetic) and percent time standing and other.

ANALYSIS

Results from the activity monitors were compared to the video review and assessed for agreement using the intraclass correlation coefficient (ICC) and accuracy of mean difference from video observation.

RESULTS

The step counts with the SAM on the non-hemiparetic limb had the highest ICC for step counts (ICC = 0.98, p < 0.001) and were overestimated with 21% accuracy. The SAM on the hemiparetic limb had 9.7% accuracy (ICC = 0.92, p < 0.001). For percent standing time all devices overestimated with poor reliability. For percent other activity time, the AP had the best accuracy and underestimated for both the hemiparetic limb (9.9% accuracy; ICC = 0.90, p < 0.001) and non-hemiparetic limb (8.3% accuracy; ICC = 0.84, p < 0.001).

CONCLUSIONS

The use of multiple devices may be warranted to capture an accurate understanding of activity levels in this population of individuals with sub-acute stroke. There are concerns with all monitors and clinicians and researchers should be aware of what measures they are wanting to understand about their population.

Microbial Biotransformation Products and Pathways of Dichloroacetamide Herbicide Safeners

Dichloroacetamide safeners are common ingredients in commercial herbicide formulations. We previously investigated the environmental fate of dichloroacetamides via photolysis and hydrolysis, but other potentially important, environmentally relevant fate processes remain uncharacterized and may yield products of concern. Here, we examined microbial biotransformation of two dichloroacetamide safeners, benoxacor and dichlormid, to identify products and elucidate pathways. Using aerobic microcosms inoculated with river sediment, we demonstrated that microbial biotransformations of benoxacor and dichlormid proceed primarily, if not exclusively, via cometabolism. Benoxacor was transformed by both hydrolysis and microbial biotransformation processes; in most cases, biotransformation rates were faster than hydrolysis rates. We identified multiple novel products of benoxacor and dichlormid not previously observed for microbial processes, with several products similar to those reported for structurally related chloroacetamide herbicides, thus indicating potential for conserved biotransformation mechanisms across both chemical classes. Observed products include monochlorinated species such as the banned herbicide CDAA (from dichlormid), glutathione conjugates, and sulfur-containing species. We propose a transformation pathway wherein benoxacor and dichlormid are first dechlorinated, likely via microbial hydrolysis, and subsequently conjugated with glutathione. This is the first study reporting biological dechlorination of dichloroacetamides to yield monochlorinated products in aerobic environments.

Evaluation of prognostic risk models for postoperative pulmonary complications in adult patients undergoing major abdominal surgery: a systematic review and international external validation cohort study

BACKGROUND

Stratifying risk of postoperative pulmonary complications after major abdominal surgery allows clinicians to modify risk through targeted interventions and enhanced monitoring. In this study, we aimed to identify and validate prognostic models against a new consensus definition of postoperative pulmonary complications.

METHODS

We did a systematic review and international external validation cohort study. The systematic review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched MEDLINE and Embase on March 1, 2020, for articles published in English that reported on risk prediction models for postoperative pulmonary complications following abdominal surgery. External validation of existing models was done within a prospective international cohort study of adult patients (≥18 years) undergoing major abdominal surgery. Data were collected between Jan 1, 2019, and April 30, 2019, in the UK, Ireland, and Australia. Discriminative ability and prognostic accuracy summary statistics were compared between models for the 30-day postoperative pulmonary complication rate as defined by the Standardised Endpoints in Perioperative Medicine Core Outcome Measures in Perioperative and Anaesthetic Care (StEP-COMPAC). Model performance was compared using the area under the receiver operating characteristic curve (AUROCC).

FINDINGS

In total, we identified 2903 records from our literature search; of which, 2514 (86·6%) unique records were screened, 121 (4·8%) of 2514 full texts were assessed for eligibility, and 29 unique prognostic models were identified. Nine (31·0%) of 29 models had score development reported only, 19 (65·5%) had undergone internal validation, and only four (13·8%) had been externally validated. Data to validate six eligible models were collected in the international external validation cohort study. Data from 11 591 patients were available, with an overall postoperative pulmonary complication rate of 7·8% (n=903). None of the six models showed good discrimination (defined as AUROCC ≥0·70) for identifying postoperative pulmonary complications, with the Assess Respiratory Risk in Surgical Patients in Catalonia score showing the best discrimination (AUROCC 0·700 [95% CI 0·683-0·717]).

INTERPRETATION

In the pre-COVID-19 pandemic data, variability in the risk of pulmonary complications (StEP-COMPAC definition) following major abdominal surgery was poorly described by existing prognostication tools. To improve surgical safety during the COVID-19 pandemic recovery and beyond, novel risk stratification tools are required.

FUNDING

British Journal of Surgery Society.

Acid- and Base-Mediated Hydrolysis of Dichloroacetamide Herbicide Safeners

Safeners are used extensively in commercial herbicide formulations. Although safeners are regulated as inert ingredients, some of their transformation products have enhanced biological activity. Here, to fill gaps in our understanding of safener environmental fate, we determined rate constants and transformation products associated with the acid- and base-mediated hydrolysis of dichloroacetamide safeners AD-67, benoxacor, dichlormid, and furilazole. Second-order rate constants for acid- (HCl) and base-mediated (NaOH) dichloroacetamide hydrolysis (2.8 × 10^-3 to 0.46 and 0.3-500 M^-1 h^-1, respectively) were, in many cases (5 of 8), greater than those reported for their chloroacetamide herbicide co-formulants. In particular, the rate constant for base-mediated hydrolysis of benoxacor was 2 orders of magnitude greater than that of its active ingredient co-formulant, S-metolachlor. At circumneutral pH, only benoxacor underwent appreciable hydrolysis (5.3 × 10^-4 h^-1), and under high-pH conditions representative of lime-soda softening, benoxacor's half-life was 13 h─a timescale consistent with partial transformation during water treatment. Based on Orbitrap LC-MS/MS analysis of dichloroacetamide hydrolysis product mixtures, we propose structures for major products and three distinct mechanistic pathways that depend on the system pH and compound structure. These include base-mediated amide cleavage, acid-mediated amide cleavage, and acid-mediated oxazolidine ring opening. Collectively, this work will help to identify systems in which hydrolysis contributes to the transformation of dichloroacetamides, while also highlighting important differences in the reactivity of dichloroacetamides and their active chloroacetamide co-formulants.

Comparing peracetic acid and hypochlorite for disinfection of combined sewer overflows: Effects of suspended-solids and pH

Peracetic acid (PAA) is an alternative disinfectant that may be effective for combined sewer overflow (CSO) disinfection, but little is known about the effect of particle size on PAA disinfection efficiency. In this work, PAA and hypochlorite were compared as disinfectants, with a focus on the effect of wastewater particles. Inactivation experiments were conducted on suspended cultures of Escherichia coli and wastewater suspended solids. Tested size fractions included particle diameters <10μm, <100μm, and raw wastewater. Chlorine disinfection efficiency decreased with increasing solids size. However, solids size had little effect on PAA disinfection. The PAA disinfection efficiency decreased at pH values above 7.5. Live/dead staining revealed that PAA disinfection leaves most cells in a viable but non-culturable condition. Fourier transform infrared spectroscopy (FTIR) analyses suggests that PAA and hypochlorite may inactivate E. coli bacteria by similar mechanisms.

NEUDOSE: A CubeSat Mission for Dosimetry of Charged Particles and Neutrons in Low-Earth Orbit

During space missions, astronauts are exposed to a stream of energetic and highly ionizing radiation particles that can suppress immune system function, increase cancer risks and even induce acute radiation syndrome if the exposure is large enough. As human exploration goals shift from missions in low-Earth orbit (LEO) to long-duration interplanetary missions, radiation protection remains one of the key technological issues that must be resolved. In this work, we introduce the NEUtron DOSimetry & Exploration (NEUDOSE) CubeSat mission, which will provide new measurements of dose and space radiation quality factors to improve the accuracy of cancer risk projections for current and future space missions. The primary objective of the NEUDOSE CubeSat is to map the in situ lineal energy spectra produced by charged particles and neutrons in LEO where most of the preparatory activities for future interplanetary missions are currently taking place. To perform these measurements, the NEUDOSE CubeSat is equipped with the Charged & Neutral Particle Tissue Equivalent Proportional Counter (CNP-TEPC), an advanced radiation monitoring instrument that uses active coincidence techniques to separate the interactions of charged particles and neutrons in real time. The NEUDOSE CubeSat, currently under development at McMaster University, provides a modern approach to test the CNP-TEPC instrument directly in the unique environment of outer space while simultaneously collecting new georeferenced lineal energy spectra of the radiation environment in LEO.

Evidence of non-response bias in the Press-Ganey patient satisfaction survey

Background

Measures of patient satisfaction have gained prominence in recent years as changes to the American health care system have led to the incorporation of such metrics into reimbursement models. The response rate for widely-used outpatient satisfaction metrics and variables influencing the probability of survey nonresponse remain largely unknown.

Methods

We reviewed all unique adult patients (16,779) who completed an outpatient encounter in the Department of Orthopaedic surgery at our academic institution from 1/1/13 to 10/24/13. Survey data was linked to each clinic visit, and patient factors including age, sex, insurance type, zip code, and orthopaedic subspecialty visited were recorded.

The overall survey response rate was calculated. Logistic regression was performed, and unadjusted and adjusted odds ratios of patients’ probability of responding to the Press-Ganey survey were calculated.

Results

Two thousand seven hundred sixty two (16.5 %) of individuals completed a Press-Ganey patient satisfaction survey and 14017 patients did not respond. For those patients considered responders, 906 patients (32.8 %) did not complete all the survey items. Among these 906 patients, the mean number of missing items was 2.24 (Standard Deviation SD: 2.19).

Age, sex, insurance type, and orthopaedic subspecialty were all found to be associated with the odds of responding to our patient satisfaction survey. Advancing age increased the odds of responding to the survey (Adjusted Odds Ratio (OR) = 3.396 for ≥65 vs. 18–29, p < 0.001). Several variables were associated with a decreased odds of survey response, and included male sex (Adjusted OR = 0.782 for Males vs. Females, p < 0.001), insurance type (Adjusted OR = 0.311 for Medicaid/Self-Pay vs. Private), and subspecialty type (Adjusted OR = 0.623 for Trauma vs. Adult Reconstruction).

Conclusions

The response rate to the Press-Ganey Medical Practice Survey of outpatient satisfaction is low in an orthopaedic outpatient population, and furthermore, is impacted by patient characteristics such as age, sex, insurance type, and type of orthopaedic subspecialist encountered. The findings of the present study should inform future non-response weighting procedures in this area. More research is needed to assess non-response bias—including follow-up studies of non-respondents—in order to more accurately measure of patient satisfaction.

HPV immunisation and increased uptake of cervical screening in Scottish women; observational study of routinely collected national data

BACKGROUND

To measure the uptake of first invitation to cervical screening by vaccine status in a population-based cohort offered HPV immunisation in a national catch-up campaign.

METHODS

A retrospective observational study of routinely collected data from the Scottish Cervical Screening Programme. Data were extracted and linked from the Scottish Cervical Call Recall System, the Scottish Population Register and the Scottish Index of Multiple Deprivation. Records from 201 023 women born between 1 January 1988 and 30 September 1993 were assessed. Women born in or after 1990 were eligible for the national catch-up programme of HPV immunisation. Attendance for screening was within 12 months of the first invitation at age 20 years.

RESULTS

There was a significant decline in overall attendance from the 1988 cohort to the 1993 cohort with the adjusted attendance ratio of the 1988 cohort being 1.49 times (95% CI 1.46-1.52) that of the 1993 cohort. Immunisation compensated for this decrease in uptake with unvaccinated individuals having a reduced ratio of attendance compared with those fully vaccinated (RR=0.65, 95% CI 0.64-0.65). Not taking up the opportunity for HPV immunisation was associated with an attendance for screening below the trend line for all women before the availability of HPV immunisation.

CONCLUSIONS

HPV immunisation is not associated with the reduced attendance for screening that had been feared. Immunised women in the catch-up cohorts appear to be more motivated to attend than unimmunised women, but this may be a result of a greater awareness of health issues. These results, while reassuring, may not be reproduced in routinely immunised women. Continued monitoring of attendance for the first smear and subsequent routine smears is needed.

Quality of Life and Comorbidities Impact Education and Employment for Survivors of Adolescent and Young Adult Cancers

Survivors of adolescent and young adult (AYA) cancers have a high risk of chronic conditions such as cardiovascular disease and asthma. These conditions may affect their ability to attend school or to work. We examined the impact of quality of life (QOL) and comorbidities on educational attainment and employment status for survivors of AYA cancers relative to a non-cancer comparison group. Methods: Using data from the 2009 Behavioral Risk Factor Surveillance System (BRFSS), we identified 7,471 individuals who were diagnosed with cancer between ages 15 and 39 and were ≥5 years from diagnosis and 326,821 controls without a history of cancer. Participants were ≥25 years of age. QOL was measured by a general health measure (excellent/very good/good/fair/poor). Comorbidities included self-reported cardiovascular disease, hypertension, asthma, and diabetes. Multivariable regressions using BRFSS survey weights were adjusted for sex, race/ethnicity and age, and compared the effects of QOL and comorbidities on educational attainment (college graduate or more vs. less education) and being employed or unable to work (compared to out of work or not in labor force) among the survivor and control groups. Results: Compared to controls, survivors in fair-poor health were less likely to be college graduates or more (survivors 18.5% vs. controls 37.9%, p &lt; 0.01) and less likely to be employed (survivors 31.7% vs. controls 61.6%, p &lt; 0.001), whereas survivors in good-excellent health did not differ from controls for either outcome. In addition, survivors in fair-poor health self-reported being unable to work more often than controls (31.4% vs. 5.4%, respectively; p &lt; 0.001). For comorbidities, inability to work ranged from 14.9% of survivors with hypertension to 27.9% of survivors with cardiovascular conditions compared to 5.4% of controls (all p &lt; 0.001), while survivors with no comorbidities did not differ from controls. Conclusions: AYA cancer survivors with ongoing health problems may face educational or work-related limitations. Early detection and management of health problems could help AYA cancer survivors control health problems before their ability to attend school or employment is disrupted.

Bicycle helmet efficacy: a meta-analysis

Bicycle helmet efficacy was quantified using a formal meta-analytic approach based on peer-reviewed studies. Only those studies with individual injury and helmet use data were included. Based on studies from several countries published in the period 1987-1998, the summary odds ratio estimate for efficacy is 0.40 (95% confidence interval 0.29, 0.55) for head injury, 0.42 (0.26, 0.67) for brain injury, 0.53 (0.39, 0.73) for facial injury and 0.27 (0.10, 0.71) for fatal injury. This indicates a statistically significant protective effect of helmets. Three studies provided neck injury results that were unfavourable to helmets with a summary estimate of 1.36 (1.00, 1.86), but this result may not be applicable to the lighter helmets currently in use. In conclusion, the evidence is clear that bicycle helmets prevent serious injury and even death. Despite this, the use of helmets is sub-optimal. Helmet use for all riders should be further encouraged to the extent that it is uniformly accepted and analogous to the use of seat belts by motor vehicle occupants.

Vehicle and driver attributes affecting distance from the steering wheel in motor vehicles

The current study was designed to confirm that female drivers sit closer to the steering wheel than do male drivers and to investigate whether this expected difference in sitting position is attributable to differences in the physical dimensions of men and women. Driver body dimensions and multiple measures of sitting distance from the steering wheel were collected from a sample of 150 men and 150 women. The results confirmed that on average, women sit closer to the steering wheel than men do and that this difference is accounted for by variations in body dimensions, especially height. This result suggests that driver height may provide a good surrogate for sitting distance from the steering wheel when investigating the role of driver position in real-world crash outcomes. The potential applications of this research include change to vehicle design that allows independent adjustment of the relative distance among the driver's seat, the steering wheel, and the floor pedals.

Genetic heterogeneity of the Coppock-like cataract: a mutation in CRYBB2 on chromosome 22q11.2

PURPOSE

To identify the genetic defect for the Coppock-like cataract (CCL) affecting a Swiss family, which defect was unlinked to the chromosome 2q33-35 CCL locus.

METHODS

A large family was characterized for linkage analysis by slit lamp examination or by the review of drawings made before cataract extraction. The affection status was attributed before genotyping, and the genotyping was masked to the affection status. Two-point and multipoint linkage analyses were performed using the MLINK and the LINKMAP components of the LINKAGE program package (ver. 5.1), respectively. Mutational analysis of candidate genes was performed by a combination of direct cycle sequencing and an amplification refractory mutation system assay.

RESULTS

Ten individuals were affected with the CCL phenotype. The disease was autosomal dominant and appeared to be fully penetrant. A new CCL locus was identified on chromosome 22q11.2 within a 11.67-cM interval (maximum lod score [Zmax] = 4.14; theta = 0). Mutational analysis of the CRYBB2 candidate gene identified a disease-causing mutation in exon 6. This sequence change was identical with that previously described to be associated with the cerulean cataract, a clinically distinct entity.

CONCLUSIONS

The CCL phenotype is genetically heterogeneous with a second gene on chromosome 22q11.2, CRYBB2. The CCL and the cerulean cataract are two distinct clinical entities associated with the same genetic defect. This work provides evidence for a modifier factor that influences cataract formation and that remains to be identified.

Women drivers' behaviour, socio-demographic characteristics and accidents

The purpose of this study was to examine factors which affect driving behaviour and accident rates in women in Australia. Two groups of women (aged 18-23 and 45-50 years) participating in the Australian Longitudinal Study on Women's Health, completed a mailed questionnaire on driver behaviour and road accidents. Self reported accident rates in the last 3 years were 1.87 per 100,000 km for the young drivers (n = 1199) and 0.59 per 100,000 km for the mid-age drivers (n = 1564); most accidents involved damage only, not injury. Mean scores for lapses obtained using the Driver Behaviour Questionnaire, were similar in the two age groups and similar to those found in other studies. In contrast, scores for errors and violations for the young women were higher than for the mid-age group and previous reports using the same instruments. Riskier driving behaviour among young women was associated with stress and habitual alcohol consumption. In the mid-age group, poorer driver behaviour scores were related to higher levels of education, feeling rushed, higher habitual alcohol consumption and lower life satisfaction scores. Accident rates in both groups were significantly related to lapses. Women born in non-English speaking countries had significantly higher risk of accidents compared to Australian-born women: relative risk = 3.40, 95% confidence interval (1.93, 5.98) for the young drivers; relative risk = 1.77, 95% confidence interval (1.11, 2.83) for mid-age drivers. These findings support the need for road safety campaigns targeted at young women to reduce dangerous driving practices, such as speeding, 'tail gating' and overtaking on the inside. There is also a need for further research to understand how lifestyle characteristics are associated with higher risk of accidents and to explore factors which might account for the higher risk for women drivers who were born overseas.

Effect of graded hypoxia on cortical and spinal somatosensory evoked potentials

Cortical somatosensory evoked potential (CSEP), spinal somatosensory evoked potential (SSEP), and electroencephalogram were recorded in rats under pentobarbital anesthesia. After baseline recordings in room air (21% O2), animals were subjected to a graded hypoxia at 15.75%, 10.5%, and 5.25% oxygen levels for 10 minutes. Each level of hypoxia was followed by a 15-minute reoxygenation period. With a moderate hypoxia (15.75% O2), measured latencies for the CSEP and the SSEP were not significantly different compared with baseline (p greater than 0.05). The CSEP amplitude showed a significant increase (p = 0.02) during reoxygenation after the moderate hypoxia. Change in the latency or amplitude of SSEP at 15.75% hypoxia or during the reoxygenation period was not significant compared with the room air (p greater than 0.05). No change in the electroencephalogram was noticed with the moderate hypoxia. At severe hypoxia (10.5% O2), 80% of the animals lost CSEP within 2 minutes. The loss of CSEP was concomitant with significant attenuation of the electroencephalogram waves. The SSEP was resistant to the severe hypoxia and was present in all animals. We concluded that hypoxia affects CSEP with the tendency to increase the amplitude at moderate hypoxia (15.75%) and loss of the latency and amplitude with severe (10.5%) and extreme (5.25%) hypoxia.

The association between Type A behavior and change in coronary risk factors among young adults

The association of Type A/B behavior pattern and changes in blood pressure, total serum cholesterol, serum triglyceride, body mass, and smoking was estimated in a cohort of 375 young Black and White men and women from a rural county in Central Kentucky between 1978-79 and 1985-88. Type A participants experienced significant increases in systolic (2.90 +/- 1.29 mmHg) and diastolic (3.80 +/- 1.17 mmHg) blood pressure and in cigarette smoking (3.26 +/- 0.89 cigarettes per day) over the eight-year follow-up period, but Type B participants experienced no change. Type A and B individuals showed similar changes in total serum cholesterol, serum triglyceride, or body mass. Differences between behavioral types in blood pressure were present for women but not men, and for Blacks but not for Whites. These findings suggest a possible significance of the Type A pattern for the development of cardiovascular risk of young adults.

The use of itemized register tapes for analysis of household food acquisition patterns prompted by children

This article describes a method of collecting and analyzing itemized grocery receipts for use in epidemiological studies. As part of a larger study of children's food acquisition and exercise habits related to cardiovascular disease, a sample of 50 families was asked to keep itemized grocery receipts for a 2-week period. To control for bias as a result of differences in food consumption and food acquisition, mothers were asked to log meals eaten away from home, food used from home production, and gifts of foods. Items on the receipts were coded according to food groups and whether they represented child-prompted purchases. The items were expressed in terms of the percentage of the food dollar each category represented. Data from the survey were compared with data collected in national surveys. The method was found to be relatively non-intrusive, easily carried out, and eliminated many of the problems associated with non-response, respondent burden, and recall characteristic of other food account methods. It is suggested as a feasible way of characterizing the family food environment in epidemiological studies.

Phase I study of oral spirogermanium

Thirty-three patients with advanced malignancy were treated with oral spirogermanium in a Phase I study to determine a maximum tolerated dose. Patients were entered in the study at doses of 100, 200, and 300 milligrams daily. The dose-limiting toxicity was gastrointestinal with moderate nausea and vomiting occurring with the 300 milligram dose. No myelosuppression or renal dysfunction was noted. Elevations of serum transaminase were seen in 41 percent of the patients at study entry. While abnormalities in hepatic function were recorded during the study, the relationship to spirogermanium could not be determined. No patient exhibited clinical hepatic dysfunction or elevation of serum bilirubin. It is recommended that future studies of oral spirogermanium incorporate careful monitoring of these parameters. Two patients with lymphoproliferative disorders had objective responses to therapy. A dose of 200 milligrams is recommended for further Phase II trials.

Baroreceptor sensitivity in prehypertensive young adults

Decreased baroreceptor reflex sensitivity has been implicated in the pathogenesis of hypertension. The purpose of this study is to determine if alterations of baroreceptor function precede the development of hypertension in humans. Baroreceptor function was evaluated in 13 young adult white men with relatively high blood pressures sustained for 12 to 15 years and 12 age-matched men with sustained relatively low blood pressures. High pressure baroreceptor activity was evaluated by measuring change in pulse interval in response to decreases and increases of arterial pressure, induced by graded infusions of nitroprusside and angiotensin II, respectively. In response to both agents, baroreceptor slopes did not differ in the high and low blood pressure groups. Plasma norepinephrine also increased similarly in both blood pressure groups in response to nitroprusside. To study low-pressure baroreceptor function, responses to graded levels of lower-body negative pressure (LBNP) were measured. Comparing both blood pressure groups, there were similar increases of heart rate, total peripheral resistance, and plasma norepinephrine in response to LBNP. Both blood pressure groups also had similar increases of heart rate and blood pressure in response to isometric (handgrip) exercise. Thus, high-pressure and low-pressure baroreceptor function is not altered in prehypertensive young adults. However, continued follow-up will be required to determine if these individuals with sustained relatively high blood pressures are truly prehypertensive.

Nutrient influences on rat intestinal phenytoin uptake

The intestinal uptake of phenytoin was studied as a function of concentration, intestinal region, coperfused glucose, and calcium chloride in rat intestinal perfusions and everted intestinal rings. Steady-state intestinal membrane permeabilities were obtained in an in situ perfusion system and initial rates of intestinal tissue uptake were obtained in an in vitro everted ring system as rate of absorption parameters. Steady-state membrane permeabilities were independent of phenytoin perfusion concentration and decreased from duodenum to ileum. Coperfusion of glucose increased, and high calcium chloride concentrations decreased phenytoin permeabilities. While phenytoin uptake in the in vitro ring system was also concentration-independent and depressed by high calcium concentrations, regional variations and glucose enhancement were not observed. Thus, drug-nutrient interactions involved in intestinal absorption from phenytoin solutions are a function of the isolation procedure.

Phase I study of echinomycin administered on an intermittent bolus schedule

We have conducted a phase I study of the cyclic peptide echinomycin (Quinomycin A) on a schedule of administration of once every 4 weeks. Ten dose levels between 20 and 1800 micrograms/m2 were studied. Acute gastrointestinal toxicity, thrombocytopenia, and transient elevations of serum transaminases occurred at doses of greater than or equal to 1000 micrograms/m2. Gastrointestinal toxicity was severe and dose-limiting in several patients at doses of 1800 micrograms/m2. Thrombocytopenia was erratic, but generally increased with drug doses. Platelet count nadirs occurred 5-10 days after administration. Hepatic toxicity was reflected in transient elevations of serum transaminases without hyperbilirubinemia. Three patients experienced apparent anaphylactic reactions to doses of 1500 micrograms/m2. The maximum tolerated single dose of echinomycin was 1800 micrograms/m2. A starting phase II dose of 1500 micrograms/m2 is recommended.

Management of blunt and penetrating injuries to the porta hepatis

Injuries to the porta hepatis pose difficult problems in management, and transection of the bile ducts, portal vein and hepatic artery is among the most challenging. Twenty-one patients with severe injuries to the porta hepatis were treated over a ten-year period. Ages ranged from 13 to 56 years, and follow-up was up to nine years. Among the 14 patients with bile duct injury, eight were found to have complete transection, and five suffered a tangential laceration or incomplete disruption with a portion of a duct wall remaining intact. Five of the eight patients who had complete transection underwent primary end-to-end repair with T-tube splinting, while three were treated with primary Roux-en-Y choledocojejunostomy. All patients with incomplete disruption underwent primary repair with or without T-tube splinting. Of the five patients with complete disruption who were treated with primary end-to-end anastomosis of the bile duct in conjunction with T-tube splinting, all required secondary biliary tract reconstruction of some type. No patient with complete transection that was treated with primary Roux-en-Y biliary enteric anastomosis required reoperation. Partial transections were successfully treated with primary repair. Portal vein injury was encountered in ten patients. Injury was successfully managed by primary closure, interposition of a vein, or splenicmesenteric vein bypass. Associated injuries to liver, pancreas, kidney and duodenum were common. In four patients there was injury to the main or left or right hepatic artery which was managed successfully by repair or ligation, with or without hepatic lobectomy. By adhering to the principles of management to be outlined, many patients with injury to the porta hepatis will survive, and the long term outcome can be gratifying.

Renin, aldosterone, electrolyte, and cortisol responses to hypoxic decompression

Responses of plasma renin activity, plasma aldosterone, plasma cortisol, and plasma electrolyte concentration and urinary electrolyte and aldosterone excretion were studied in four men during hypoxic decompression to a stimulated altitude of 4,760 m in a pressure chamber. Three of the four subjects developed significant acute mountain sickness. Plasma sodium and potassium concentrations were unchanged. No significant change in plasma renin activity was observed, but values tended to fall. Plasma aldosterone concentration was depressed while plasma cortisol was elevated and diurnal variation lost. Urinary sodium excretion was unchanged, but urinary potassium and aldosterone excretion were decreased. The decrease in plasma and urinary aldosterone and urinary potassium in the absence of change in plasma renin activity or plasma potassium is of uncertain origin. It is unlikely to be due to a decrease in adrenocorticotropin secretion since plasma cortisol rose during the same time. None of the changes could be causally implicated in the development of acute mountain sickness although the increase in plasma cortisol was greatest in the most ill.

Sex differences in adolescent alcohol and drug use. A disappearing phenomenon

In a study of junior and senior high-school students in two Massachusetts communities, few consistent sex differences were found in patterns of alcohol and drug use.