Management of unstable angina: the role of noninvasive risk stratification

Many cardiologists rely primarily on catheterization to evaluate, and revascularization to treat, patients with unstable angina. In this era of managed care and cost containment, it is useful to determine whether some patients with unstable angina might benefit sufficiently from noninvasive testing and medical therapies. Several studies provide evidence that myocardial perfusion imaging is valuable for evaluating cardiac risk and thus determining the best candidates for medical treatment. Comparative studies indicate that myocardial perfusion imaging is superior to stress electrocardiography for assessing risk in patients with unstable angina.

Amrinone stimulation test: ability to predict improvement in left ventricular ejection fraction after coronary bypass surgery in patients with poor baseline left ventricular function

OBJECTIVES

This study sought to determine whether the response to amrinone in patients with severe baseline left ventricular dysfunction can predict improvement in left ventricular ejection fraction after coronary artery bypass graft surgery.

BACKGROUND

Previous studies have suggested that the inotropic response to dobutamine can identify viable myocardium in the setting of chronic coronary disease and left ventricular dysfunction. However, increased oxygen demand stimulated by dobutamine can lead to superimposition of ischemia on the hibernating state, potentially confounding interpretation of results. Amrinone is an inotropic agent that does not critically augment myocardial oxygen demand and may be useful for identification of hibernating myocardium in the chronically ischemic state.

METHODS

Forty-four consecutive patients with coronary artery disease and left ventricular ejection fraction < 40% referred for coronary artery bypass graft surgery underwent amrinone stimulation (1 mg/kg body weight). Left ventricular ejection fraction was determined before amrinone stimulation, 20 min after infusion and 21 days after bypass surgery.

RESULTS

Baseline ejection fraction was 28 +/- 7% (mean +/- SD). Ejection fraction increased to 35 +/- 5% after amrinone stimulation (p < 0.0001) and to 33 +/- 6% after bypass surgery (p < 0.0001). Postbypass ejection fraction was significantly correlated with postamrinone ejection fraction (r = 0.65, p < 0.0001). Furthermore, the change in ejection fraction from baseline to after bypass surgery was highly correlated with the change in ejection fraction after amrinone stimulation (r = 0.75, p < 0.0001). Of 13 patients with an increase in ejection fraction > or = 10% after amrinone, all 13 had an increase of at least 8% and 11 (85%) of 13 had an increase > or = 10% after bypass surgery. In contrast, of 31 patients with an increase in ejection fraction < 10% after amrinone, only 2 (6%) had an increase > or = 10% (p < 0.0001) and 28 (90%) of 31 had an increase < 5% after bypass surgery.

CONCLUSIONS

Augmentation of myocardial contraction by amrinone in patients with chronic coronary artery disease and severe baseline left ventricular dysfunction predicts improvement in left ventricular ejection fraction after coronary artery bypass graft surgery.

Prognostic value of myocardial perfusion imaging: state of the art and new developments

Although the prognostic value of myocardial perfusion imaging is now well established, new data have continued to expand its role in the management of patients. This review addresses the current state-of-the-art and new developments in the use of myocardial perfusion imaging for determining cardiac risk and integrating such information into patient care.

Reduction of Acute Low Back Injuries by Use of Back Supports

The objective of this study was to determine the effect of a change in back-support-use policy on the occurrence of work-related low back injuries among a large cohort of employees in the retail-trade home improvement industry. Working hours of exposure, back support use, and intensity of materials-lifting requirements were collected from 1989 through 1994. Records of injury-related claims were reviewed for all documented injuries to the lower back among members of the cohort during the same period. Over 101,000,000 working hours were recorded by nearly 36,000 employees; 2,152 employees reported an acute low back injury occurring during working hours as a first report of episode, with medical-physician diagnosis and acute/abrupt onset. Incidence density rates were calculated for persons wearing and not wearing the back support. Rate ratios and prevented fractions were evaluated. Before implementation of a company-wide back-support policy, the employees had a rate of acute low back injuries of 30.6 per million working hours. After implementation, this rate fell to 20.2 per million working hours, a significant reduction of 34.0%. This effect was seen in both genders, in younger workers and in those aged 55+, with low levels of lifting as well as high lifting intensities, and in persons with one to two years of employment with the company. The authors conclude that uniform mandatory implementation of a back-support-use policy significantly reduces the incidence of acute low back injuries incurred in the workplace.

Child pedestrian and bicyclist injuries: results of community surveillance and a case-control study

OBJECTIVES

To describe the dimensions of childhood pedestrian and bicyclist injuries in Long Beach, California, and to identify risk factors for these injuries.

POPULATION

Long Beach residents aged 0-14 years who were involved in an auto versus pedestrian or bicyclist incident that resulted in a hospital visit and/or police response, between 1 September 1988 and 31 August 1990.

METHODS

Cases were identified retrospectively using hospital charts, police records, and coroner's reports; demographic, clinical, and situational information were abstracted from the same. A nested case-control study was conducted to examine the street environments where children were injured, and to identify environmental risk factors at these case sites.

RESULTS

288 children comprised the sample population. Midblock dart-outs emerged as the single most common type of incident. Most incidents happened on residential streets, but the risk of injury was greatest on larger boulevards, and tended to cluster by region within the city. Adjusted odds ratios show that case sites had a larger proportion of traffic exceeding posted speed limits, and were also four times more likely to be near a convenience store, gas station, or fast food store than control sites.

CONCLUSIONS

The findings of this study suggest three possible routes for the prevention of childhood pedestrian and bicyclist injuries: education, law enforcement, and environmental modification.

Geographic and temporal patterns of recurrent intentional injury in south-central Los Angeles

To better understand geographic and temporal patterns of recurrent intentional injury, 285 consecutive trauma patients were evaluated prospectively. Fifteen were excluded because of immediate death or severe brain injury. The remaining 270 patients were interviewed. Of these, 59 (22%) had been treated in a hospital for a total of 75 previous episodes of intentional trauma (mean: 1.3 episodes/patient). In 66 of the 75 episodes, the patient recalled where treatment had been received (88%). Twenty-eight (42%) of the 66 episodes had been treated at King/Drew Medical Center (KDMC), 36 (55%) had been treated at a hospital within a 3-mile radius of KDMC, 48 (73%) within an 8-mile radius, and 63 (95%) within a 10-mile radius. Sixty-five percent of the episodes occurred 5 years or less prior to the current injury (range: 11 days to 30 years; mean: 4.9 years). Patients currently admitted for intentional injury were more likely to have had intentional injury previously than those with unintentional injury (27% versus 12%). Based on these findings, we conclude that intentional trauma patients in our community remain in a defined geographic region and that there is a definable high-risk period for recurrent intentional injury. These conclusions should enhance the development of a framework on which future violence prevention programs can be designed.

Human sequences homologous to the gene for the cochlear protein Ocp-II do not map to currently known non-syndromic hearing loss loci

The abundant and almost exclusive expression of OCP-II protein in the mammalian cochlea has fuelled speculation that mutations in the OCP2 gene may result in inherited forms of hearing impairment. We have identified several human sequences related to OCP2 and sublocalised three of these OCP2 related loci to 4q12-p14 or 4p16.2-pter, 5q15-q21.3 and 7p22-q22 by PCR. 2 YACs with sequence consistent with the chromosome 7 locus were also used for FISH analysis and hybridised to chromosome 7q11. Our data suggest that the cytogenetic localisations of these OCP2 related sequences do not correlate with the precise chromosomal positions of deafness loci so far identified.

The site of acute myocardial infarction is related to the coronary territory of transient defects on prior myocardial perfusion imaging

BACKGROUND

Prior studies have established the prognostic value of myocardial perfusion imaging. In particular, the presence and extent of transient defects have been shown to predict future cardiac events including acute myocardial infarction. However, the relationship between the location of the perfusion defect and the site of subsequent myocardial infarction remains unclear.

METHODS AND RESULTS

Review of prior records of consecutive patients admitted with acute myocardial infarction identified 34 patients whose prior myocardial perfusion imaging studies had demonstrated transient defects and no interval revascularization. The coronary artery territory of the transient defects was identified and related to the site of subsequent acute myocardial infarction. To reduce the potentially confounding effect of progression of coronary artery disease between the time of the myocardial perfusion imaging study and subsequent infarction, patients were divided into those less than 2 years and those 2 years or greater between imaging and infarction. Among patients with a transient defect and less than 2 years between infarction and imaging, 11 (79%) of 14 had a myocardial infarction in the same coronary territory as their prior transient defect (p < 0.0005). This association decreased to only five (25%) of 20 when the interval was 2 years or greater (difference not significant). Among 22 patients who had undergone prior coronary angiography, myocardial infarction occurred in the same coronary territory as the most severe angiographic stenosis in 12 (54%). The association was not related to the time interval between angiography and infarction.

CONCLUSIONS

There is a strong association between the coronary territory of transient defects on myocardial perfusion imaging and the site of subsequent myocardial infarction when the duration is less than 2 years. These observations support the concept that the hemodynamic significance of a coronary lesion is an important factor in the pathophysiology of acute myocardial infarction.

Skeletal muscle and cardiovascular adaptations to exercise conditioning in older coronary patients

BACKGROUND

Older coronary patients suffer from a low functional capacity and high rates of disability. Supervised exercise programs improve aerobic capacity in middle-aged coronary patients by improving both cardiac output and peripheral extraction of oxygen. Physiological adaptations to aerobic conditioning, however, have not been well studied in older coronary patients.

METHODS AND RESULTS

The effect of a 3-month and a 1-year program of intense aerobic exercise was studied in 60 older coronary patients (mean age, 68 +/- 5 years) beginning 8 +/- 5 weeks after myocardial infarction or coronary bypass surgery. Outcome measures included peak aerobic capacity, cardiac output, arterio-venous oxygen difference, hyperemic calf blood flow, and skeletal muscle fiber morphometry, oxidative enzyme activity, and capillarity. Training results were compared with a sedentary, age- and diagnosis-matched control group (n = 10). Peak aerobic capacity increased in the intervention group at 3 months and at 1 year by 16% and 20%, respectively (both P < .01). Peak exercise cardiac output, hyperemic calf blood flow, and vascular conductance were unaffected by the conditioning protocol. At 3 and 12 months, arteriovenous oxygen difference at peak exercise was increased in the exercise group but not in control subjects. Histochemical analysis of skeletal muscle documented a 34% increase in capillary density and a 23% increase in succinate dehydrogenase activity after 3 months of conditioning (both P < .02). At 12 months, individual fiber area increased by 29% compared with baseline (P < .01).

CONCLUSIONS

Older coronary patients successfully improve peak aerobic capacity after 3 and 12 months of supervised aerobic conditioning compared with control subjects. The mechanism of the increase in peak aerobic capacity is associated almost exclusively with peripheral skeletal muscle adaptations, with no discernible improvements in cardiac output or calf blood flow.

IL-6 acts on endothelial cells to preferentially increase their adherence for lymphocytes

Using a quantitative monolayer adhesion assay, the current report shows that treatment of human umbilical vein endothelial cells (HUVEC) with IL-6 increases their adhesiveness for blood lymphocytes, particularly CD4+ cells, but not for polymorphonuclear cells and monocytes. This effect, which was most pronounced when using low concentrations of the cytokine (0.1-1.0 U/ml) and a short incubation period (4h), was also apparent with microvascular endothelial cells and a hybrid endothelial cell line. Skin lesions from patients with mycosis fungoides contain high levels of IL-6, and blood lymphocytes from patients with this disorder also exhibited an enhanced adhesion to IL-6-treated HUVEC. The cytokine enhanced intercellular adhesion molecule-1 (ICAM-1) expression and induced the expression of vascular cell adhesion molecule-1 (VCAM-1) and E-selectin on endothelial cells. Antibody blocking studies demonstrated that the vascular adhesion molecules ICAM-1, VCAM-1 and E-selectin and the leucocyte integrin LFA-1 all contributed to lymphocyte binding to endothelium activated by IL-6. It is proposed that IL-6 may be involved in the recruitment of lymphocytes into non-lymphoid tissue.

Enhanced binding of lymphocytes from patients with multiple sclerosis to tumour necrosis factor-alpha (TNF-alpha)-treated endothelial monolayers: associations with clinical relapse and adhesion molecule expression

This study investigated the adherent properties and adhesion molecule expression of blood mononuclear cells (MNC) from a total of 84 patients with multiple sclerosis (MS). The MNC from MS patients were significantly more adherent than cells from normal healthy subjects to endothelial monolayers pretreated with 0.01 U/ml TNF-alpha (103% increase; P = 0.002), 0.1 U/ml TNF-alpha (80% increase; P < 0.01) and 1.0 U/ml TNF-alpha (41% increase; P < 0.02), and to endothelium pretreated with 10 U/ml IL-1 beta (44% increase; P < 0.05) and 100 U/ml interferon-gamma (IFN-gamma) (100% increase; P < 0.05). This augmented adhesion was a property of the lymphocytes, in particular CD4+ cells, and was inversely related to the time of onset of clinical relapse. The percentage of lymphocytes bearing the adhesion molecules CD49d, CD29 and CD62L was increased in MS blood, but the level of CD29 and CD62L expression was reduced. We infer that circulating lymphocytes in MS are predisposed to cross endothelial barriers at sites where inflammation has already commenced.

Ventilatory parameters in children during propofol anaesthesia: a comparison with halothane

PURPOSE

The purpose of this study was to compare the effects of propofol on ventilation with those of halothane.

METHODS

Respiration was studied in 20 spontaneously breathing children undergoing elective dental restoration randomized to receive either propofol (Group P) or halothane (Group H) anaesthesia. Data were recorded at different inspired concentrations of halothane (F1H) or propofol (RivP) during a washout of the anaesthetic agent. The F1H 2%, 1% and 0% corresponded to an end-tidal halothane concentration of 1.38 +/- 0.06%, 0.857 +/- 0.03% and 0.191 +/- 0.01% respectively. The RivP were 18, 15, 12, 9 and 0 mg.kg-1.hr-1. The inspiratory flow waveform, the CO2 waveform and the occluded inspiratory pressure waveform were recorded. The flow waveform was analyzed for minute ventilation (Vi), and tidal volume (VT), parameters of breath Timing [Total time (Ttot), Inspiratory time (Ti)] and parameters of breath Amplitude [mean inspiratory flow (VT/Ti)]. The slope of the initial 100 msec (dP/dt0.1) of an occluded inspiration, together with the occluded inspiratory time (Tiocc) and the ratio of the occluded to unoccluded inspiratory time (Tiocc/Ti) were obtained.

RESULTS

There were intergroup differences in the preemergence values of Ttot, dP/dt0.1 and Tiocc/Ti. In group P the Vi, VT and Ttot increased and PETCO2 decreased during a washout of propofol. The values of dP/dt0.1 in Group P at all RivP were half the values of those in Group H. The ratio Tiocc/Ti did not change in Group P and increased in Group H during a washout of halothane.

CONCLUSION

Propofol anaesthesia was associated with a decrease in Vi whereas during halothane anaesthesia, Vi did not change. Ventilation in Group P differed from Group H in parameters of both breath Drive and Timing.

Forensic implications of the variation in morphology of marginal serrations on the teeth of the great white shark

The teeth of the Great White Shark have been examined to ascertain whether there is any commonality in the arrangement or number of the marginal serrations (peaks) or, indeed, whether individual sharks have a unique pattern of shapes or size of the peaks. The teeth of the White Shark are characteristic in size and shape with serrations along almost the entire mesial and distal margins. This study has revealed no consistent pattern of size or arrangement of the marginal serrations that was sufficiently characteristic within an individual shark to serve as a reliable index of identification of a tooth as originating from that particular shark. Nonetheless, the serrations are sufficiently distinctive to enable the potential identification of an individual tooth as having been the cause of a particular bitemark.

Two-dimensional and dobutamine stress echocardiography in the preoperative assessment of patients with end-stage liver disease prior to orthotopic liver transplantation

Orthotopic liver transplantation is an established therapy for end-stage liver disease. This study evaluated the range of cardiovascular abnormalities in patients undergoing evaluation for orthotopic liver transplantation and determined the prognostic implications of abnormal echocardiographic features, including ischemia during dobutamine stress echocardiography, in predicting postoperative cardiac events. Two-dimensional echocardiography was performed in 190 patients for assessment of left ventricular function, valvular pathology, and pulmonary hypertension. Dobutamine stress echocardiography was performed in 165 patients for evaluation of inducible ischemia. Contrast echocardiography for detection of intrapulmonary shunting was performed in 125 patients at rest and in 99 during dobutamine stress. Left ventricular dysfunction, significant valvular regurgitation, and inducible ischemia were identified in <1O% of patients. Pulmonary hypertension, left ventricular hypertrophy and > or = moderate intrapulmonary shunting were present in 12%, 16%, and 26% of patients, respectively. Severe intrapulmonary shunting predicted death prior to transplantation (P=0.01). Of the 71 transplanted patients, major perioperative events included global left ventricular dysfunction in four patients and myocardial infarction in one patient with normal coronary arteries. No preoperative echocardiographic parameters, including ischemia on dobutamine echocardiography, predicted these perioperative events. No cardiac events related to obstructive coronary artery disease occurred in the 154 patients without ischemia on dobutamine stress echocardiography. The majority of patients with end-stage liver disease, including those with alcoholic cirrhosis, have normal cardiac function on two-dimensional echocardiography. Severe intrapulmonary shunting portends a poor prognosis in patients awaiting transplantation. A negative dobutamine stress echocardiogram appears useful in excluding patients at risk for perioperative cardiac events related to obstructive coronary artery disease.

bcl-2 is down-regulated in atypical endometrial hyperplasia and adenocarcinoma

The bcl-2 protein, which protects cells from apoptosis, is normally expressed in a number of adult tissues. Dysregulated bcl-2 expression, secondary to (14;18) chromosomal translocation, seems to promote the development of follicular lymphomas, and recent findings of bcl-2 protein in several solid tumors suggest that it might contribute to the genesis of many other neoplasms. bcl-2 is also highly expressed in normal proliferative endometrium and markedly down-regulated in secretory endometrium, which suggests that its expression is estrogen regulated. Because the development of most endometrial carcinomas is associated with hyperestrogenic states, we began the investigation of the role of bcl-2 in endometrial carcinogenesis by immunohistochemically quantifying its expression in proliferative, hyperplastic, atypically hyperplastic, and carcinomatous endometrium. The results of this study show that bcl-2 is relatively highly expressed in proliferative (n = 11) and hyperplastic (n = 18) endometrium, with respective mean staining scores of 3.59 and 3.47 (scale, 0-4), but is significantly (P < 0.001) down-regulated in atypical hyperplasia (n = 11; score, 0.82), and adenocarcinoma (n = 34; score, 0.86). bcl-2 expression did not correlate with stage, grade, estrogen-receptor, or progesterone-receptor expression. Polymerase chain reaction analyses of DNA isolated from several endometrial carcinomas were negative for (14;18) translocation involving the bcl-2 gene. Thus, bcl-2 apparently plays no role in the progression of atypical hyperplasia to carcinoma or in the development of high-grade or advanced-stage endometrial carcinoma. These results, however, do not rule out the involvement of bcl-2 in very early, preatypical hyperplasia phases of endometrial carcinogenesis. Finally, the marked difference in bcl-2 expression in hyperplastic and atypically hyperplastic glands might prove to be diagnostically useful in the often difficult distinction of these entities.

Development and validation of a Bayesian model for perioperative cardiac risk assessment in a cohort of 1,081 vascular surgical candidates

OBJECTIVES

This study sought to develop and validate a Bayesian risk prediction model for vascular surgery candidates.

BACKGROUND

Patients who require surgical treatment of peripheral vascular disease are at increased risk of perioperative cardiac morbidity and mortality. Existing prediction models tend to underestimate risk in vascular surgery candidates.

METHODS

The cohort comprised 1,081 consecutive vascular surgery candidates at five medical centers. Of these, 567 patients from two centers ("training" set) were used to develop the model, and 514 patients from three centers were used to validate it ("validation" set). Risk scores were developed using logistic regression for clinical variables: advanced age (>70 years), angina, history of myocardial infarction, diabetes mellitus, history of congestive heart failure and prior coronary revascularization. A second model was developed from dipyridamole-thallium predictors of myocardial infarction (i.e., fixed and reversible myocardial defects and ST changes). Model performance was assessed by comparing observed event rates with risk estimates and by performing receiver-operating characteristic curve (ROC) analysis.

RESULTS

The postoperative cardiac event rate was 8% for both sets. Prognostic accuracy (i.e., ROC area) was 74 +/- 3% (mean +/- SD) for the clinical and 81 +/- 3% for the clinical and dipyridamole-thallium models. Among the validation sets, areas were 74 +/- 9%, 72 +/- 7% and 76 +/- 5% for each center. Observed and estimated rates were comparable for both sets. By the clinical model, the observed rates were 3%, 8% and 18% for patients classified as low, moderate and high risk by clinical factors (p<0.0001). The addition of dipyridamole-thallium data reclassified >80% of the moderate risk patients into low (3%) and high (19%) risk categories (p<0.0001) but provided no stratification for patients classified as low or high risk according to the clinical model.

CONCLUSIONS

Simple clinical markers, weighted according to prognostic impact, will reliably stratify risk in vascular surgery candidates referred for dipyridamole-thallium testing, thus obviating the need for the more expensive testing. Our prediction model retains its prognostic accuracy when applied to the validation sets and can reliably estimate risk in this group.

The accumulation of multiple genetic abnormalities in individual tumor cells in human breast cancers: clinical prognostic implications

PURPOSE

Human solid tumors undergo multiple genetic evolutionary changes as they evolve from the normal state to advanced stages of malignancy. This study characterizes the degree of advancement of primary human breast cancers in their genetic evolutionary pathways, and determines if this is of clinical significance.

MATERIALS AND METHODS

Correlated cell-by-cell measurements of cell DNA content, HER-2/neu protein content per cell, and H-ras protein content per cell were obtained by means of multiparameter flow cytometry on primary tumors from 95 patients with clinically localized breast cancer. Laboratory findings were correlated with subsequent clinical course in 91 of these patients.

RESULTS

Multiple genetic abnormalities were found to accumulate in individual cells in primary human breast cancers. Almost all tumors contained subsets of cells with one, two, or three abnormalities per cell in various combinations. After a median follow-up time of 32 months, 11 of 13 patients with early recurrence had primary tumors in which more than 5% of cells were hypertetraploid, overexpressed HER-2/neu protein, and overexpressed H-ras protein (triple-positive cells). The duration of disease-free survival among patients with primary tumors that contained triple-positive cells was significantly shorter than for patients whose tumors did not contain triple-positive cells. The presence of subpopulations of cells with maximums of only one abnormality per cell or only two abnormalities per cell, in any combination, was of no prognostic significance. Among patients whose nodal status was known, 12 had recurrent disease, and all had positive axillary nodes. Among 36 patients known to have negative axillary nodes, no recurrence has been reported to date.

CONCLUSIONS

The number of genetic abnormalities that accumulate in individual cells in primary breast cancers reflects the degree of advancement of a tumor in its genetic evolutionary sequence, and provides useful clinical prognostic information. Because follow-up duration is still relatively short, and because disease in node-negative patients tends to recur later than in node-positive patients, it is still too early to know if three measurements per cell will be sufficient to improve prognosis in node-negative disease.

Pattern of ventilation during halothane anaesthesia in infants less than two months of age

PURPOSE

To examine the breathing pattern of infants aged less than two months in order to understand better the effect of halothane on ventilation in infants.

METHODS

The inspiratory flow waveform, the CO2 waveform and occluded inspiratory pressure waveform were recorded at different inspired concentrations of halothane using a washout of halothane in two groups of infants undergoing elective herniorrhaphy. Data were analyzed for minute ventilation (Vi) and tidal volume (VT), parameters of timing of the breath [Total time (Ttot), Inspiratory time (Ti), and the ratio of the occluded to unoccluded inspiratory time (TiOCC/Ti)], parameters of Amplitude of the neural output [mean inspiratory flow (VT/Ti)] and parameters of the Shape of the inspiratory breath profile [the inspiratory flow centroid (Ci/Ti), the inspiratory duty cycle (Ti/Ttot)]. The airway was occluded at end expiration and the slope of the initial 100 msec of occlusion (dP/dt) together with the maximal negative pressure (PMAX) and occluded inspiratory time (TiOCC) were obtained. We studied ten infants < 48 wk post-conceptional age (PCA) and ten infants > 48 wk. PCA Flow (V), pressure (Pao) and carbon dioxide tension (PCO2) were recorded at three concentrations of inspired halothane (FiH): 0%, 1% and 2% which corresponded to an end-tidal halothane concentration of about 0.2%, 0.8% and 1.2% respectively.

RESULTS

In both groups Vi, VT and VT/Ti decreased whereas dP/dt, did not, suggesting that the respiratory pump was impaired. The parameters of breath Shape did not change. Importantly the parameters of Timing showed different tendencies. In infants > 48 wk PCA TiOCC/Ti decreased. In infants < 48 wk PCA, TiOCC/Ti did not change.

CONCLUSIONS

The different response in the timing parameter TiOCC/Ti is consistent with a different effect of halothane on parameters of ventilatory timing in infants < 48 wk PCA and this may represent a maturational effect.

The effects of meal schedule and quantity on problematic behavior

We present 2 case examples that illustrate the effects of meal schedule and quantity on displays of problematic behavior. In the first example, self-injury displayed by a toddler with severe developmental delays was maintained by parent attention, but only when he was satiated for food. When he was food deprived, self-injury decreased but did not appear to be differentiated across low or high social conditions. In the second example, crying and self-injury displayed by an elementary-aged girl with severe disabilities were correlated: Both behaviors were associated with food quantity, and neither behavior was responsive to social stimuli. These results replicate and extend previous findings demonstrating that meal schedule or food quantity can affect problematic behavior. In the present studies, brief functional analyses of aberrant behavior provided useful information for interpreting distinct patterns of behavior displayed by each child. We discuss these results in terms of the concept of establishing operations.

Choice-making treatment of young children's severe behavior problems

The choice-making behavior of 5 young children with developmental disabilities who engaged in aberrant behavior was studied within a concurrent operants framework. Experimental analyses were conducted to identify reinforcers that maintained aberrant behavior, and functional communication training packages were implemented to teach the participants to gain reinforcement using mands. Next, a choice-making analysis, in which the participants chose one of two responses (either a mand or an alternative neutral response) to obtain different durations and qualities of reinforcement, was conducted. Finally, treatment packages involving choice making via manding were implemented to decrease inappropriate behavior and to increase mands. The results extended previous applications of choice making to severe behavior disorders and across behaviors maintained by positive and negative reinforcement.

Gender differences in parenting a child with cancer

This study of 124 parents of children diagnosed with cancer investigates parents' perceptions of their role in the illness situation. The study found that mothers and fathers differ in their experience of and response to parenting a child with cancer. These differences appear to reflect traditional parenting roles characterized by a gender-based division of labor. Sex-role socialization theory is discussed as an explanatory model of the parenting experience. Practice recommendations are offered to medical social workers and other health care professionals concerned about the long term psychosocial adjustment of parents with chronically ill children.

Linkage studies of non-syndromic recessive deafness (NSRD) in a family originating from the Mirpur region of Pakistan maps DFNB1 centromeric to D13S175

Autosomal recessive non-syndromal hearing impairment (NSRD) is genetically heterogeneous. Five loci have been identified to date which map to chromosomes 13 (DFNB1), 11 (DFNB2), 17 (DFNB3), 7 (DFNB4) and 14 (DFBN5). We report definite linkage of NSRD to the locus DFNB1 in a single family of 27 families studied of Pakistani origin. Haplotype analysis of markers in the pericentromeric region of chromosome 13q revealed a recombination event which maps DFNB1 proximal to the marker D13S175 and in the vicinity of D13S143.

Quantitative forensic evaluation of bite marks with the aid of a shape analysis computer program: Part 1; The development of "SCIP" and the similarity index

Bite marks left on human tissue and bitten material have become an important aspect of scientific evidence used for the conviction or acquittal of a suspect. Expert opinion has often been based on subjective comparisons rather than any objective metrical analysis and many experts will agree that there is a need to employ additional comparative tests to achieve unbiased objectivity in their investigation. In this study, an interactive shape analysis computer program ("SCIP"-Shape Comparison Interactive Program) has been employed in an attempt to derive experimentally a quantitative comparison, in the form of a Similarity Index (S.I.), between the "offender's" teeth and the bite marks produced on a standard flat wax form. The S.I. values obtained using "SCIP" were evaluated in a variety of experimental bite mark situations. It was found that in no case could the S.I. values produced by comparison of the bite mark with the dental casts from non-perpetrators be confused with the much lower S.I. from comparison of the bite mark with the dental cast of the perpetrator. The use of the Similarity Index derived using the "SCIP" program is recommended as a simple, accurate and objective means of comparing bite marks in suitable forensic cases.

A bitemark and a fracture?

The kidnap and brutal murder of the eleven year-old daughter of a fire brigade officer in the town of Wassenaar in the Netherlands on September 29, 1980, resulted in the first ever appearance of a forensic odontologist as an expert witness in the history of Dutch law. This previously unpublished case is now reviewed for its historic significance, and also because it presents an interesting problem of interpretation of odontological evidence relevant to the identification of the offender, and raises issues concerning proper procedures for the utilisation of expertise in forensic odontology.