Fallibility of tattooing colonic neoplasia ahead of laparoscopic resection: a retrospective cohort study

INTRODUCTION

Precise geographical localisation of colonic neoplasia is a prerequisite for proper laparoscopic oncological resection. Preoperative endoscopic peri-tumoural tattoo practice is routinely recommended but seldom scrutinised.

METHODS

A retrospective review of recent consecutive patients with preoperative endoscopic lesional tattoo who underwent laparoscopic colonic resection as identified from our prospectively maintained cancer database with supplementary clinical chart and radiological, histological, endoscopic and theatre database/logbook interrogation.

RESULTS

Some 210 patients with 'tattooed' colonic neoplasia were identified, of whom 169 underwent laparoscopic surgery (mean age 68 years, median BMI 27.8kg/m2, male-to-female ratio 95:74). The majority of tumours were malignant (149; 88%), symptomatic (133; 79%) and proximal to the splenic flexure (92; 54%). Inaccurate colonoscopist localisation judgement occurred in 12% of cases, 60% of which were corrected by preoperative staging computed tomography scan. A useful lesional tattoo was absent in 11/169 cases (6.5%) being specifically stated as present in 104 operation notes (61%) and absent in 10 (5.9%). Tumours missing overt peritumoral tattoos intraoperatively were more likely to be smaller, earlier stage and injected longer preoperatively (p=0.006), although half had histological ink staining. Eight lesions missing tattoos were radiologically occult. Four (44%) of these patients had on-table colonoscopy, and five (55%) needed laparotomy (conversion rate 55% vs 23% overall, p<0.005) with one needing a second operation to resect the initially missed target lesion. Mean (range) operative duration and postoperative length of stay of those missing tattoos compared with those with tattoos was 200 (78-300) versus 188 (50-597) min and 15.5 (4-22) versus 12(4-70) days (p>0.05).

CONCLUSIONS

Tattoo in advance of attempting laparoscopic resection is vital for precision cancer surgery especially for radiologically unseen tumours to avoid adverse clinical consequence.

TP3-5 Structural connectivity driven stereoelectroencephalography (SEEG) electrode targeting in suspected pseudotemporal and temporal plus epilepsy

Objectives

One third of patients with drug resistant focal mesial temporal lobe epilepsy (MTLE) fail to achieve long-term seizure freedom following temporal lobe resections. Reasons for failure may include ictal onset outside the temporal lobe (TL), termed ‘pseudotemporal lobe epilepsy’ (pTLE), with propagation from strongly connected neighboring areas or temporal plus (TL+) epilepsy, when the epileptogenic zone primarily involves the temporal lobe and also extends to neighboring regions. In such cases the perisylvian and orbito-frontal (OF) cortices, cingulum and temporo-parieto-occipital junction may be implicated. Stereoelectroencephalography (SEEG) is a procedure in which electrodes are stereotactically placed within predefined brain regions to delineate the SOZ and allows evaluation of deep anatomical structures adjacent to the TL. SEEG electrode contacts sample from a core radius of 3–5 mm. It is unclear which sub-regions of target structures should be preferentially implanted to optimally detect the network involved in seizure onset and rapid propagation. Using normalized average group templates of structural connectivity from patients with hippocampal sclerosis (HS), we determine the greatest connectivity to critical sub-regions and based upon this propose optimal locations for SEEG targeting.

Design

Observational cross-sectional study.

Subjects

Twelve patients with HS (6 right) that had undergone SEEG and pre-operative diffusion imaging were identified from a prospectively maintained database.

Methods

Whole brain connectomes with 10 million tracts were generated using cortical seed regions derived from whole brain GIF parcellations. Normalized group templates were generated separately for right and left HS patients. Orbitofrontal cortex (OF), insula (INS), cingulum (Cing) and temporo-parietal-occipital junction (supramarginal gyrus, angular gyrus, precuneus, fusiform gyrus and lingual gyrus) were segmented into surgically targetable subregions. All subregions had similar volumes. Connectivity of the amygdalohippocampal complex (AHC) was defined based on the number of streamlines terminating in the subregions of interest.

Results

Left HS showed preferential connections to the ipsilateral: posterior part of lateral OF cortex, posterior short gyrus of anterior INS, posterior part of the posterior Cing, middle part of lingual gyrus, posterior part of precuneus and middle part of fusiform gyrus. Right HS showed preferential connections to the ipsilateral: posterior part of the lateral OF cortex, anterior long gyrus of posterior INS, posterior part of posterior Cing, anterior part of lingual gyrus and posterior part of precuneus.

Conclusions

Using whole brain connectomes we determine surgically feasible targets in sub-regions based on greatest connectivity to the AHC. We propose that SEEG targeting utilizing computer-assisted planning may improve the understanding of the overall network connectivity in order to enhance the diagnostic utility of the SEEG implantation. SEEG electrode placement within structures associated with pTLE and TL +may aid in delineating the SOZ if the correct sub-regions are targeted. This should be evaluated prospectively.

P30 A PRISMA systematic review and meta-analysis of open and novel ‘minimally invasive’ techniques for mesial temporal lobe epilepsy (MTLE)

Objectives

One third of patients with focal epilepsy fail to achieve seizure freedom despite best medical therapy. Surgery may provide seizure freedom if the epileptogenic zone can be safely remove. We compare the outcomes following open surgery, laser interstitial thermal therapy (LITT), radiofrequency ablation (RFA) and radiosurgery (RS).

Design

PRISMA systematic review and meta-analysis.

Subjects

MTLE

Methods

Structured searchs of PubMed, Embase and Cochrane databases. Random effects meta-analysis to calculate effects sizes and a pooled estimate of the probability of remaining seizure free at one year following intervention.

Results

From 1212 screened publications, 57 articles were included in the quantitative analysis. Open surgery included anterior temporal lobectomy as well as transcortical, subtemporal and transsylvian selective amygdalohippocampectomy. The probability of remaining seizure free at one year was 0.89 (95% CI 0.83–0.93) with open surgery based on Level 1 and 2 evidence. RS resulted in 0.88 (95% CI 0.84–0.90) probability and a single RCT revealed RS was less efficacious than open surgery. Follow up duration and study sizes were limited with LITT and RFA providing a probability of remaining seizure free at one year of 0.71 (95% CI 0.65–0.76) and 0.86 (95% CI 0.76–0.92) respectively.

Conclusions

There is no evidence supporting novel ‘minimally invasive’ approaches as being as efficacious as open surgery. Secondary outcome measures such as neuropsychological outcome and intervention morbidity are poorly reported.

TP3-4 Changes in whole brain connectomes with simulated laser interstitial thermal therapy (LITT) using seizure free and non-seizure free ablation cavities in mesial temporal sclerosis: a graph theory approach

Objectives

LITT is a novel means of focal lesioning. Improved seizure free outcome has been associated with the extent to which the mesial hippocampal head is ablated, but not overall ablation volume. We question whether specific changes in structural network connectivity exist in patients that achieve seizure freedom.

Design

Retrospective

Subjects

25 MTS patients after LITT with 2 year outcome.

Methods

Ablation cavities from 11 seizure free and 14 non-seizure free patients were combined to generate group masks. In 12 separate pre-operative patients with MTS (6 right), weighted normalized connectomes were generated with 1 × 10^7 streamlines. To simulate ablations the group cavity masks were excluded from the connectomes prior to normalization. Differences in connectomes were assessed by graph theory metrics.

Results

Greater node strength (str) in non-seizure free patients were present in the ipsilateral basal temporo-occipital cortices in both right and left MTS. Str and local efficiency were relatively maintained in the ipsilateral thalamus of seizure free cavities. Betweenness centrality in non-seizure free cavities were greater in ipsilateral temporal poles in right and left MTS.

Conclusions

Differences in network connectivity are present following simulated LITT for MTS between seizure free and non-seizure free ablation cavities. LiTT ablation cavities may be pre-operatively modelled to ensure the ablation cavity includes important structures and non-essential or inhibitory connectivity is spared. Prospective validation is required.

P35 Ability to quantify stereoelectroencephalography (SEEG) electrode trajectory proximity to vessels across imaging protocols

Objectives

Automated planning of stereoelectroencephalography (SEEG) electrode trajectories is dependent on vessel segmentation.1 We quantify imaging protocols ability to measure trajectory-to-vessel distance.

Design

Retrospective analysis.

Subjects

Ten consecutive patients were selected whom had SEEG implantation (95 electrodes) and Digital Catheter Subtraction Angiography (DSA) with catheterization of carotid or vertebral arteries, post-gadolinium T1-weighted (GAD), phase-contrast MR angiography and MR venography (MR) acquired.

Methods

SEEG trajectories were planned manually with DSA. Minimum distance to vessels and risk1 were computed for each trajectory using vessel segmentation from GAD, MR, or DSA. Vessel size was considered by including DSA vessels diameters above 1, 2, 3, or 4 mm.

Results

Minimum distance to a vessel was 6.2±3.9 mm (GAD), 2.5±1.6 mm (MR), and 1.5±1.2 mm (DSA). Based on DSA vessel size minimum distances were 2.0±1.5 mm (DSA >1 mm), 3.4±2.6 (DSA >2 mm), 6.6±4.6 mm (DSA >3 mm), and 11.8±7.9 mm (DSA >4 mm). Risk was 0.4±0.4 (GAD), 0.8±0.4 (MR), and 1.1±0.2 (all DSA), 1.0±0.2 (DSA >1 mm), 0.7±0.4 (DSA >2 mm), 0.4±0.5 (DSA >3 mm), and 0.2±0.3 (DSA >4 mm).

Conclusions

DSA is best able to segment vessels. MR has metrics similar to DSA vessels above 2 mm. GAD has metrics similar to DSA vessels above 3 mm.

WP1-15 Computer-assisted versus manual planning for stereotactic brain biopsy: retrospective comparative pilot study

Objectives

Stereotactic brain biopsy is among the most common neurosurgical procedures. Planning a safe surgical trajectory requires careful attention to a number of features including:

traversing the skull perpendicularly;

avoiding critical neurovascular structures; and

minimising trajectory length.

The aim of this study was to develop a platform, SurgiNav, for automated trajectory planning in stereotactic brain biopsy.

Methods

A prospectively maintained database was searched between February and August 2017 to identify all adult patients that underwent stereotactic brain biopsy in whom post-operative imaging was available. In each case, the standard pre-operative T1-weighted gadolinium-enhanced MRI was used to generate models of the cortex and vasculature. A surgical trajectory was then generated using automated computer-assisted planning (CAP) and metrics compared to the trajectory of the implemented manual plan (MP) using the paired T-test.

Results

15 consecutive patients were identified; who had a diagnostic biopsy and there were no immediate complications. Feasible trajectories were generated using CAP in 12 patients, and in these the mean trajectory length using CAP was comparable to MP (31.7 mm vs. 37.1 mm; p=0.3), and mean angle was similarly perpendicular from orthogonal (9.3° vs. 15.3° p=0.1), but the risk-metric was significantly lower (0.16 vs. 0.48; p=0.03).

Conclusions

Computer-assisted planning for stereotactic brain biopsy appears feasible in most cases and may be safer in selected cases.

P31 Optimising trajectories in computer assisted planning for cranial laser interstitial thermal therapy: a machine learning approach

Objectives

Optimal trajectory planning for cranial laser interstitial thermal therapy (cLITT) in drug resistant focal mesial temporal lobe epilepsy (MTLE).

Design

A composite ablation score of ablated AHC minus ablated PHG volumes were calculated and normalised. Random forest and linear regression were implemented to predict composite ablation scores and determine the optimal entry and target point combinations to maximize this.

Subjects

Ten patients with hippocampal sclerosis were included.

Methods

Computer Assisted Planning (CAP) cLITT trajectories were generated using entry regions that include the inferior occipital gyri (IOG), middle occipital gyri (MOG), inferior temporal gyri (ITG) and middle temporal gyri (MTG). Target points were varied by sequential erosions and transformations of the centroid of the amygdala. In total 760 trajectory combinations were generated per patient and ablation volumes were calculated based on a conservative 15 mm maximum ablation diameter.

Results

Linear regression was superior to random forest predictions. Linear regression indicated that maximal composite ablation scores were associated with entry points that clustered around the junction of the IOG, MOG and MTG. The optimal target point was a translation of the centroid of the amygdala anteriorly and medially.

Conclusions

Machine learning techniques accurately predict composite ablation scores with linear regression outperforming the random forest approach. Optimal CAP entry points for cLITT maximize ablation of the AHC and spare the PHG.

A Type 1 Diabetes Genetic Risk Score Predicts Progression of Islet Autoimmunity and Development of Type 1 Diabetes in Individuals at Risk

OBJECTIVE

We tested the ability of a type 1 diabetes (T1D) genetic risk score (GRS) to predict progression of islet autoimmunity and T1D in at-risk individuals.

RESEARCH DESIGN AND METHODS

We studied the 1,244 TrialNet Pathway to Prevention study participants (T1D patients' relatives without diabetes and with one or more positive autoantibodies) who were genotyped with Illumina ImmunoChip (median [range] age at initial autoantibody determination 11.1 years [1.2-51.8], 48% male, 80.5% non-Hispanic white, median follow-up 5.4 years). Of 291 participants with a single positive autoantibody at screening, 157 converted to multiple autoantibody positivity and 55 developed diabetes. Of 953 participants with multiple positive autoantibodies at screening, 419 developed diabetes. We calculated the T1D GRS from 30 T1D-associated single nucleotide polymorphisms. We used multivariable Cox regression models, time-dependent receiver operating characteristic curves, and area under the curve (AUC) measures to evaluate prognostic utility of T1D GRS, age, sex, Diabetes Prevention Trial-Type 1 (DPT-1) Risk Score, positive autoantibody number or type, HLA DR3/DR4-DQ8 status, and race/ethnicity. We used recursive partitioning analyses to identify cut points in continuous variables.

RESULTS

Higher T1D GRS significantly increased the rate of progression to T1D adjusting for DPT-1 Risk Score, age, number of positive autoantibodies, sex, and ethnicity (hazard ratio [HR] 1.29 for a 0.05 increase, 95% CI 1.06-1.6; P = 0.011). Progression to T1D was best predicted by a combined model with GRS, number of positive autoantibodies, DPT-1 Risk Score, and age (7-year time-integrated AUC = 0.79, 5-year AUC = 0.73). Higher GRS was significantly associated with increased progression rate from single to multiple positive autoantibodies after adjusting for age, autoantibody type, ethnicity, and sex (HR 2.27 for GRS >0.295, 95% CI 1.47-3.51; P = 0.0002).

CONCLUSIONS

The T1D GRS independently predicts progression to T1D and improves prediction along T1D stages in autoantibody-positive relatives.

Measurements of the proton elastic-form-factor ratio mu pG p E/G p M at low momentum transfer

High-precision measurements of the proton elastic form-factor ratio, mu pG p E/G p M, have been made at four-momentum transfer, Q2, values between 0.2 and 0.5 GeV2. The new data, while consistent with previous results, clearly show a ratio less than unity and significant differences from the central values of several recent phenomenological fits. By combining the new form-factor ratio data with an existing cross-section measurement, one finds that in this Q2 range the deviation from unity is primarily due to G p E being smaller than expected.

The social context of smoking: the next frontier in tobacco control?

A better understanding of the social context of smoking may help to enhance tobacco control research and practice.

Peaks of linkage are localized by a BAC/PAC contig of the 6p reading disability locus

A gene for reading disability has been localized by nonparametric linkage to 6p21.3-p22 in several published reports. However, the lack of an uninterrupted genomic clone contig has made it difficult to determine accurate intermarker distances, precise marker order, and genetic boundaries and hinders direct comparisons of linkage. The search and discovery of the hemochromatosis gene (HFE) led to the creation of a bacterial artificial chromosome (BAC) and P-1 derived artificial chromosome (PAC) contig that extended physical maps 4 Mb from the MHC toward pter and localized new markers in that region [10-12]. Using this contig, we localized 124 sequence tagged sites, expressed sequence tags, and short tandem repeats including most of the markers in linkage with reading disability phenotypes, succinic semialdehyde dehydrogenase, GPLD1, prolactin, and 18 uncharacterized genes. This new contig joins and extends previously published physical maps to span the entire chromosome 6 reading disability genetic locus. Physical mapping data from the complete contig show overlap of the published linkage peaks for reading disability, provide accurate intermarker distances and order, and offer resources for generating additional markers and candidate genes for high resolution genetic studies in this region.

Rats with hypothalamic obesity are insensitive to central leptin injections

Genetically determined obesities, involving leptin- and melanocortin-signaling pathways, have focused attention on the four medial hypothalamic nuclei as primary sources of feeding- and metabolically-based obesity. All four medial cell groups contain leptin receptors. To determine which of these cell groups normally mediates the effects of leptin on food intake and body weight gain, we injected colchicine bilaterally into each nucleus and determined the pathophysiological effects of disruption and responsivity to leptin injected intracerebroventricularly. Intracerebroventricular injections of leptin in sham-lesioned rats decreased food intake during the dark period, but not during the light period. Lesions of the arcuate (ARC), paraventricular (PVN), and ventromedial (VMN) nuclei all resulted in leptin insensitivity; by contrast, lesions of the dorsomedial nuclei (DMN) augmented sensitivity to leptin on feeding and body weight gain. Although rats with ARC and PVN lesions were obese, they were still capable of reducing caloric efficiency over the 5 days of study and increasing uncoupling protein content in interscapular brown adipose tissue. Caloric efficiency and uncoupling protein content were unchanged in rats with VMN and DMN lesions. Finally, the slope of the relationship between leptin and mesenteric white adipose tissue was increased in rats with VMN lesions and abolished in rats with ARC lesions. Thus, lesions of the ARC, PVN, and VMN produced obesity via separate pathways. We conclude that the medial hypothalamic cell groups, each with a different role in energy balance, are all necessary for normal leptin responsiveness.

A telling tale: a case of vigilantism and its aftermath in an English town

This paper considers one 'vigilante' episode in an English town in 1993 and its subsequent appearances in the press and in local 'crime-talk'. In so doing it a) proposes as an alternative to most current constructions of 'fear of crime' an interpretive approach grounded in place; b) considers the intersections between the generic 'law and order' preoccupations of the national press and the salience in local knowledge of a particular sequence of events (and their consequences for their dramatis personae); c) raises conjecturally some preconditions favouring the adoption of the 'vigilante' option amongst available styles of security-seeking action. Theoretically, the paper demonstrates the relevance of locally-circulating stories of crime and low-level street disorder to the contemporary understanding of crime, place and community.

Facilitation of internal locus of control in adolescent alcoholics through a brief biofeedback-assisted autogenic relaxation training procedure

The purpose of the study was to determine if autogenic relaxation training facilitated through biofeedback promotes an increase in internal levels of locus of control. The participants were residents of two Southwest Missouri alcohol treatment centers and ranged in age from 18 to 21 years. Treatment and control groups were compared on their responses on the Drinking Related Locus of Control Scale (DRIE) and fingertip temperature pre- and posttraining. The training was effective in teaching autogenic relaxation as demonstrated by increased fingertip temperature for the treatment group posttraining, while no differences were observed for the control group. Most importantly, the treatment group was not only significantly more internal in their locus of control after training but were also significantly more internal than the control group posttraining. Given that alcoholics are significantly more external in their locus of control than nonalcoholics, and that an internal locus of control implies an individual's belief that he or she has control and is responsible for his or her behavior, autogenic relaxation facilitated through biofeedback may be a very important component in therapeutic intervention for adolescent alcoholics.

Role of intelligence tests in speech/language referrals

This study examined the relation of the WISC-R Verbal IQ with measures of oral and written language among 190 students referred to a private educational clinic over a 5-yr. period. Correlations of Verbal IQ with scores on measures of oral language, written language, receptive language, reading comprehension, and basic reading skills were calculated for the total sample and by Grades 1-3, 4-7, and 8-11. Standard regression coefficients were used to estimate the proportion of variance explained by these five measures. Significant correlations were found for Verbal IQ with the measures, ranging from .36 (Basic Reading Skills) to .69 (Receptive Vocabulary). Multiple regression indicated that 59% of the variance was explained by the five measures and that three--Oral Language, Receptive Vocabulary, and Reading Comprehension--contributed significantly to Verbal IQ. Correlations across grades showed inconsistent differences by grade for Verbal IQ with language variables. Implications for speech-language referral practices are discussed.

Effects of direct instruction in Spanish phonology on the native-language skills and foreign-language aptitude of at-risk foreign-language learners

This study examined the effect of an academic year of direct instruction in the phonology/orthography of Spanish on the native-language skills and foreign-language aptitude of high school women identified as at risk (n = 14) and not at risk (n = 19) for experiencing problems with learning a foreign language. At-risk students received a specialized teaching approach; not-at-risk students received traditional foreign-language instruction. Pre- and posttest results showed that both groups improved significantly on a foreign-language aptitude test, and the at-risk group made significant gains on native-language phonology/orthography measures. Pretest comparisons showed significant between-group differences on several phonological/orthographic measures and the foreign-language aptitude test. Posttest comparisons showed that the not-at-risk subjects still scored significantly higher than at-risk subjects on the foreign-language aptitude measure; no differences were noted on two native-language phonological/orthographic measures. Pre- and posttest comparisons between groups showed that the at-risk group made significantly greater gains than the not-at-risk group on phonological/orthographic measures. Implications for instruction are presented.

The effects of multisensory structured language instruction on native language and foreign language aptitude skills of at-risk high school foreign language learners

Research findings suggest that most students who have foreign language learning problems have language-based difficulties and, in particular, phonological processing problems. Authors of the present study examined pre- and posttest scores on native language and foreign language aptitude tests of three groups of at-risk high school students enrolled in special, self-contained sections of first-year Spanish. Two groups were instructed using a multisensory structured language (MSL) approach. One of the groups was taught in both English and Spanish (MSL/ES), the other only in Spanish (MSL/S). The third group (NO-MSL) was instructed using more traditional second language teaching methodologies. Significant gains were made by the MSL-ES group on measures of native language phonology, vocabulary, and verbal memory and on a test of foreign language aptitude; the MSL/S group made significant gains on the test of foreign language aptitude. No significant gains on the native language or foreign language aptitude measures were made by the NO-MSL group. Implications for foreign language classroom instruction of at-risk students are discussed.

Cell cycle status of stromal cells in long-term haematopoietic cultures

This study was performed to further define the mechanism by which the stromal micro-environment regulates haematopoiesis. In long-term marrow cultures the interactions between stromal cells and haematopoietic cells can be investigated at the cellular level. Long-term marrow cultures from hamsters do not require repopulation or addition of hydrocortisone and are suitable for investigation of cell kinetics. The cellular kinetics of haematopoietic and stromal cells, as studied by tritiated thymidine ([3H]dT) incorporation, revealed that DNA synthesis occurred in both the non-adherent and the adherent cells. In established cultures the adherent stromal cells were predominantly in a quiescent non-cycling state: less than 2% adherent cells incorporated [3H]dT within 5 h. Removal of the supernatant cells did not affect the labelling index of adherent cells, since the labelling indices at the 50-75 h time point were 14.3% and 12.5% in the presence and absence of supernatant cells respectively. An apparent stimulus for stromal cells to incorporate [3H]dT was attachment or adhesion. Following replating of supernatant cells of long-term marrow cultures, 23.3% of the reformed adherent layer cells were labelled compared with 12-14% in cultures with previously formed unmobilized adherent cells (P less than 0.01). The data indicate that adherent cells are not required to synthesize DNA for maintenance of haematopoiesis in established long-term marrow cultures, and that recruitment into the cell cycle has an independent mechanism that is not influenced by feed-back from the supernatant cells.

Linguistic coding deficits in foreign language learners

As increasing numbers of colleges and universities require a foreign language for graduation in at least one of their degree programs, reports of students with difficulties in learning a second language are multiplying. Until recently, little research has been conducted to identify the nature of this problem. Recent attempts by the authors have focused upon subtle but ongoing language difficulties in these individuals as the source of their struggle to learn a foreign language. The present paper attempts to expand upon this concept by outlining a theoretical framework based upon a linguistic coding model that hypothesizes deficits in the processing of phonological, syntactic, and/or semantic information. Traditional psychoeducational assessment batteries of standardized intelligence and achievement tests generally are not sensitive to these linguistic coding deficits unless closely analyzed or, more often, used in conjunction with a more comprehensive language assessment battery. Students who have been waived from a foreign language requirement and their proposed type(s) of linguistic coding deficits are profiled. Tentative conclusions about the nature of these foreign language learning deficits are presented along with specific suggestions for tests to be used in psychoeducational evaluations.

Separation of immature and adult rat hepatocytes into distinct subpopulations by centrifugal elutriation

Several subpopulations of hepatocytes with increasing cell diameters were isolated, the smaller cells were attributed to the periportal area, the larger ones to the perivenous region. Profiles of total cytochrome P-450, benzphetamine N-demethylation and ethoxyresorufin O-deethylation, cytochrome c-reductase, glucose-6-phosphatase and GPT activities were determined. With adult hepatocytes an increasing cytochrome P-450 concentration with increasing cell diameter could be observed, paralleled by increasing activities of monooxygenases. Glucose-6-phosphatase and GPT also revealed increasing activities with increasing cell diameter, but cytochrome c-reductase did not show a distinct zonation. Immature hepatocytes (age 11-15 days) were smaller, more fragile, and could not be isolated with the same enzyme solution as adult hepatocytes. They did not show any zonation of cytochrome P-450 whereas the zonation of the monooxygenases was almost fully developed. For cytochrome c-reductase a zonation with higher activities in the perivenous cells could be demonstrated, in contrast to the lack of zonation in adult rats. Glucose-6-phosphatase showed a decline with increasing cell diameter in immature hepatocytes, whereas GPT did not show any zonation. In rats aged 20 days the zonation of these parameters in liver was in between younger and older animals.

Predictors of drug-resistant Mycobacterium tuberculosis

Drug susceptibility testing is usually performed when Mycobacterium tuberculosis organisms are recovered from Asian immigrants or from patients whose sputum remains culture positive despite several months of antituberculosis medication. Alcoholism, previous antituberculosis treatment, history of adverse reactions to previous treatment, and patient unreliability have also been suggested as risk factors, but the ability of these factors to predict the presence of drug-resistant organisms has not been assessed. Starting in January 1980, the Washington State Tuberculosis Laboratory began testing every positive M. tuberculosis culture for drug resistance. This enabled us to prospectively evaluate the sensitivity and specificity of 7 risk factors for drug resistance in consecutive patients. From January 1, 1980, through December 31, 1982, cultures from 803 patients were positive for M. tuberculosis; 766 of these (95%) were tested for drug resistance. The incidence of resistance was 13% (101/766). Of the 101 patients with drug-resistant organisms, 61 (60%) were Asian, supporting the need to routinely test Asian immigrants for drug-resistant disease. The ability of the other risk factors to separate the 40 non-Asians (40%) with drug-resistant disease from the group of 513 non-Asians with drug-sensitive organisms was poor. All risk factors were insensitive and had a high false positive rate. These results demonstrate that the presence of drug-resistant disease in non-Asians cannot accurately be predicted. This finding suggests that all cultures of M. tuberculosis should be tested for drug sensitivity, and that in areas where the incidence of drug resistance is sufficiently high, initial treatment should be with 3 drugs until drug susceptibility is known.

Young adult, geriatric and aphasic group responses to simple analogies

The efficiency of interactive language processing was compared in three groups: 25 young adults, 25 geriatric subjects, and 25 adult aphasic subjects. The task involved simple analogy completion. Data analysis included six categories of responses which represetned levels of convergence toward the expected relationships. Results of chi-square comparisons between groups were all significant, and indicated substantial reductions in interactive processing for geriatric subjects. The findings suggest that a general aging factor may contribute to the poor prognosis in elderly aphasic patients.