Pediatric critical care training programs have a positive effect on pediatric intensive care mortality

OBJECTIVE

Comparison of severity and diagnosis-adjusted mortality rates from pediatric intensive care units (ICUs) staffed by physicians training in pediatric critical care, as well as pediatric residents, with mortality rates from pediatric ICUs staffed with only pediatric residents.

DESIGN

Cohort study.

SETTING

Sixteen volunteer pediatric ICUs, eight with critical care fellowships, and eight without such programs.

PATIENTS

Consecutive admissions until at least 14 deaths occurred at each site.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Descriptive data and Pediatric Risk of Mortality scores were collected. Severity and diagnosis-adjusted mortality risk for each patient was computed by a predictor developed in an independent sample. The effect of fellowship programs was analyzed at the institution level by ranking the pediatric ICUs in terms of observed/predicted mortality rates, and, at the patient level, by including a training factor into the predictor model. The use of monitoring and therapeutic modalities was compared in the two types of pediatric ICUs by severity-adjusted odds ratios. There were 2,744 admissions (145 deaths) to the eight fellowship pediatric ICUs and 3,006 admissions (150 deaths) to the eight nonfellowship pediatric ICUs. Institutional characteristics were not different between the two pediatric ICU sets. The raw mortality rates were similar (fellowship 5.28%; nonfellowship 4.99%, p = .714). Institution-level analyses indicated that fellowship pediatric ICUs performed better than nonfellowship pediatric ICUs; fellowship pediatric ICUs ranked better than pediatric ICUs without such programs (Wilcoxon rank-sum test, p = .020). However, both the best and the worst ranked pediatric ICUs had fellowships. Patient-level analyses also indicated that outcome was significantly influenced by the fellowship status of the pediatric ICU. Using two different patient-level analytic approaches, the odds of dying in a fellowship pediatric ICU vs. a nonfellowship pediatric ICU were 0.592 (95% confidence interval 0.468 to 0.749, p = .0001) and 0.714 (95% confidence interval 0.529 to 0.964, p = .028). Pediatric ICUs with fellowship programs performed more (p < .05) invasive monitoring, including intra-arterial catheters and central venous pressure catheters, and more technological therapies such as mechanical ventilation.

CONCLUSIONS

Pediatric ICUs with critical care fellowship programs are generally associated with better risk-adjusted mortality rates than pediatric ICUs without such fellowship training programs. The cause for this effect requires a more in-depth study. The presence or absence of such training programs does not guarantee superior or inferior performance.

The Pediatric Risk of Mortality III--Acute Physiology Score (PRISM III-APS): a method of assessing physiologic instability for pediatric intensive care unit patients

OBJECTIVE

To develop a physiology-based measure of physiologic instability for use in pediatric patients that has an expanded scale compared with the Pediatric Risk of Mortality (PRISM) III score.

STUDY DESIGN

Data were collected from consecutive admissions to 32 pediatric ICUs (11,165 admission, 543 deaths). Patient-level data included physiologic data, outcomes, descriptive information, and diagnoses. Physiologic data included the most abnormal values in the first 24 hours of pediatric ICU stay from 27 variables. Initially, ranges of each physiologic variable were evaluated for their association with mortality. A multi-variate logistic regression analysis was used to determine the final variables and their ranges. Integer scores reflecting the relative contribution to mortality risk were assigned to the variable ranges.

RESULTS

A total of 59 ranges of 21 physiologic variables were selected. This score is called the Pediatric Risk of Mortality III--Acute Physiology Score (PRISM III-APS). Mortality increased as the PRISM III-APS score increased. Most patients have PRISM III-APS scores less than 10, and these patients have a mortality risk of less than 1%. At the other extreme, the mortality rate of the 137 patients with a PRISM III-APS score of greater than 80 was greater than 97%.

CONCLUSION

The PRISM III-APS score is an expanded measure of physiologic instability that has been validated against mortality. Compared with PRISM III, PRISM III-APS should be more sensitive to small changes in physiologic status.

Ideal timing of pediatric laryngotracheal reconstruction

OBJECTIVE

To determine whether there is an ideal age at which to perform a laryngotracheal reconstruction (LTR) in the pediatric population.

DESIGN

Prospective observational study.

SETTING

Tertiary care children's hospital.

PATIENTS

Forty-eight patients aged 48 months or younger with laryngotracheal stenosis who underwent 50 LTRs from October 1, 1986, to June 30, 1995. Patients were divided into 2 groups: group 1, aged 8 through 24 months (22 patients); group 2, aged 25 through 48 months (26 patients).

INTERVENTION

Endoscopy and LTR.

MAIN OUTCOME MEASURES

Successful decannulation.

RESULTS

Statistical analysis showed that (1) patients in group 2 had more severe degree of laryngotracheal stenosis as determined by duration of stenting with no difference in multiple sites of stenosis or type of repair required to correct laryngotracheal stenosis and (2) patients in group 2 were more likely to have successful decannulation.

CONCLUSION

Laryngotracheal reconstruction at a younger age (< 25 months) is important for a child's speech and language development as well as for eliminating the morbidity and mortality associated with a tracheotomy. However, LTR at a younger age is associated with a higher risk of failure despite lesser degree of pathology. Therefore, although we still recommend LTR at a younger age since it may be beneficial for a child's speech and language development and avoidance of tracheotomy complications, this recommendation may be at the price of LTR failure and requirement for revision procedures.

Correlation of P-glycoprotein expression and function in childhood acute leukemia: a children's cancer group study

Clinical drug resistance may be attributed to the simultaneous selection and expression of genes modulating the uptake and metabolism of chemotherapeutic agents. P-glycoprotein (P-gp) functions as a membrane-associated drug efflux pump whose increased expression results in resistance to anthracyclines, epipodophyllotoxins, vinca alkaloids, and some alkylating agents. This type of resistance occurs as both de novo and acquired resistance to therapy for leukemia. We have studied P-gp expression and function in childhood acute leukemias by developing a series of doxorubicin- and vincristine-selected CEM, T-cell lymphoblastoid cell lines that recapitulate the low levels of expression and resistance seen clinically. These cell lines have been used to develop flow cytometric assays for the semiquantitative measurements of P-gp expression with the MRK16 monoclonal antibody and P-gp function using the enhanced retention of rhodamine 123 in the presence of verapamil, a resistance modulator. Kolmogorov-Smirnov statistics, represented by the D measurement, are used to determine the difference in level of P-gp expression by comparing MRK16 staining to an IgG2a isotype control. When D is > 0.09, there is an excellent correlation (R = 0.82) between P-gp expression and function. The evaluation of 107 bone marrow specimens from 84 children with lymphoblastic or myelogenous leukemia showed a statistically significant (P = .004) increase in P-gp function at relapse. P-gp expression at relapse, however, approached but did not reach a significant level (P = .097). Using this methodology, we can identify patients with levels of P-gp expression and function that we can define clinically, as well as children with discordant multidrug resistance phenotypes. This study supports the role of P-gp-mediated drug resistance in childhood leukemia and confirms that P-gp expression and function are measurable in their leukemic blasts. These assays provide the means for the in vitro testing of resistance modulators and the monitoring of in vivo response to treatment with these agents.

PRISM III: an updated Pediatric Risk of Mortality score

OBJECTIVES

The relationship between physiologic status and mortality risk should be reevaluated as new treatment protocols, therapeutic interventions, and monitoring strategies are introduced and as patient populations change. We developed and validated a third-generation pediatric physiology-based score for mortality risk, Pediatric Risk of Mortality III (PRISM III).

DESIGN

Prospective cohort.

SETTING

There were 32 pediatric intensive care units (ICUs): 16 pediatric ICUs were randomly chosen and 16 volunteered.

PATIENTS

Consecutive admissions at each site were included until at least 11 deaths per site occurred.

MEASUREMENTS AND MAIN RESULTS

Physiologic data included the most abnormal values from the first 12 and the second 12 hrs of ICU stay. Outcomes and descriptive data were also collected. Physiologic variables where normal values change with age were stratified by age (neonate, infant, child, adolescent). The database was randomly split into development (90%) and validation (10%) sets. Variables and their ranges were chosen by computing the risk of death (odds ratios) relative to the midrange of survivors for each physiologic variable. Univariate and multivariate statistical procedures, including multiple logistic regression analysis, were used to develop the PRISM III score and mortality risk predictors. Data were collected on 11,165 admissions (543 deaths). The PRISM III score has 17 physiologic variables subdivided into 26 ranges. The variables most predictive of mortality were minimum systolic blood pressure, abnormal pupillary reflexes, and stupor/coma. Other risk factors, including two acute and two chronic diagnoses, and four additional risk factors, were used in the final predictors. The PRISM III score and the additional risk factors were applied to the first 12 hrs of stay (PRISM III-12) and the first 24 hours of stay (PRISM III-24). The Hosmer-Lemeshow chi-square goodness-of-fit evaluations demonstrated absence of significant calibration errors (p values: PRISM III-12 development = .2496; PRISM III-24 development = .1374; PRISM III-12 validation = .4168; PRISM III-24 validation = .5504). The area under the receiver operating curve and Flora's z-statistic indicated excellent discrimination and accuracy (area under the receiver operating curve - PRISM III-12 development 947 +/- 0.007; PRISM III-24 development 0.958 +/- 0.006; PRISM III-12 validation 0.941 +/- 0.021; PRISM III-24 validation 0.944 +/- 0.021; Flora's z-statistic - PRISM III-12 validation = .7479; PRISM III-24 validation = .9225), although generally, the PRISM III-24 performed better than the PRISM III-12 models. Excellent goodness-of-fit was also found for patient groups stratified by age (significance levels: PRISM III-12 = .1622; PRISM III-24 = .4137), and by diagnosis (significance levels: PRISM III-12 = .5992; PRISM III-24 = .7939).

CONCLUSIONS

PRISM III resulted in several improvements over the original PRISM. Reassessment of physiologic variables and their ranges, better age adjustment for selected variables, and additional risk factors resulted in a mortality risk model that is more accurate and discriminates better. The large number of diverse ICUs in the database indicates PRISM III is more likely to be representative of United States units.

Risk factors for nosocomial infection in critically ill children: a prospective cohort study

OBJECTIVE

To identify factors in pediatric intensive care unit (ICU) patients that are associated with an increased risk of nosocomial infections.

DESIGN

A prospective, 1-yr cohort study.

SETTING

A 16-bed pediatric ICU in a multidisciplinary, regional referral center.

SUBJECTS

All patients admitted to the pediatric ICU.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The primary outcome variable was the development of nosocomial infection. Out of 945 consecutive admissions, 75 patients developed 96 nosocomial infections. The most frequent infection sites were the lower respiratory tract (35%), the bloodstream (21%), and the urinary tract (21%). The most common organisms isolated were Gram-negative bacteria (53%, Gram-positive bacteria (27%), and fungi (9%). Variables significantly associated with the development of nosocomial infections included age, weight, Pediatric Risk of Mortality (PRISM) score, device utilization ratio, antimicrobial therapy, histamine-2 (H2) receptor blocker use, immune status, parenteral nutrition, and length of stay. When combined in a multivariate logistic regression model, the significant variables were operative status, PRISM score, device utilization ratio, antimicrobial therapy, parenteral nutrition, and length of stay before the onset of infection. The area under the receiver operating characteristic curve was 0.868. At a probability of 0.15, the sensitivity was 66.67%, and the specificity was 87.82%.

CONCLUSIONS

Patients at risk for developing nosocomial infection can be identified using a multivariate logistic regression model with a high degree of sensitivity and specificity. These data indicate that institutional nosocomial rates need to be adjusted for risk factors. This model could help target patients at high risk for developing nosocomial infections for preventive strategies.

The effect of gastroesophageal reflux on laryngotracheal reconstruction

OBJECTIVES

To determine the need for preoperative evaluation for gastroesophageal reflux disease (GERD) in all children undergoing laryngotracheal reconstruction (LTR) and to assess the effect of GERD on the outcome of LTR.

DESIGN

Prospective, single-blind observational study.

SETTING

Tertiary care children's hospital.

PATIENTS

Seventy-four pediatric patients with laryngotracheal stenosis who underwent LTR at the Children's National Medical Center, Washington, DC, from October 1, 1986, through August 31, 1994.

INTERVENTION

Evaluation for and treatment of GERD, LTR, endoscopy, and removal of granulation tissue.

MAIN OUTCOME MEASURES

Successful decannulation and number of endoscopies required to remove laryngeal and tracheal granulation tissue.

RESULTS

Seventy-four patients underwent 82 LTRs. The senior surgeon was blinded to the status of GERD evaluation and treatment. Four groups were identified: 37 patients (40 LTRs) with no preoperative evaluation for GERD; 10 patients (11 LTRs) with normal findings on preoperative evaluation for GERD; seven patients (nine LTRs) with abnormal findings on preoperative evaluation for GERD but who failed to receive appropriate treatment; and 20 patients (22 LTRs) with abnormal findings on preoperative evaluation for GERD who received appropriate therapy. Severity and extent of stenosis as determined by multicentricity of stenosis, type of repair, and duration of stent were similar in the four groups. The effect of GERD and its treatment on the outcome of LTR was measured by the number of endoscopies necessary for removal of granulation tissue following reconstruction and successful decannulation. Statistical analyses indicate that (1) all children do not require preoperative evaluation for GERD; (2) neither the presence of GERD nor its treatment are major factors in determining the outcome of LTR.

CONCLUSION

Preoperative evaluation for GERD and its treatment do not favorably affect the outcome of LTR.

Frequency of variable measurement in 16 pediatric intensive care units: influence on accuracy and potential for bias in severity of illness assessment

OBJECTIVES

We evaluated: a) whether the frequency of variable measurement could influence the performance of the Pediatric Risk of Mortality (PRISM) score; b) whether measurement frequency of physiologic variables varied between individual pediatric intensive care units (ICUs), and c) if so, how much of this variability could be attributed to institution-level and patient-level factors.

DESIGN

Prospective cohort.

SETTING

Sixteen pediatric ICUs, chosen for their diversity.

PATIENTS

Consecutive admissions (n = 5,415).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

First, the measurement frequency of the 14 physiologic variables in the PRISM score was included in the logistic regression model predicting mortality risk. Measurement frequency was not significant, alone or in its interaction with the PRISM score. Second, the presence or absence of measurement of each physiologic variable was included in the logistic model using indicator variables; none was significant. Finally, the contribution of the individual pediatric ICUs and patient factors in explaining the variability in the frequency of physiologic variable measurement were investigated with linear regression analysis. In this analysis, the separation of severity of illness from measurement frequency was accomplished by computing the PRISM score from the first 4 hrs and measurement frequencies from hours 5 through 24. Overall, 70.22% (r2) of the variability of measurement frequency could be explained by the factors included in the linear regression model. The individual ICUs accounted for a total of only 6.23% of the explained variability and no individual hospital accounted for > 1.44% of the variability. Other variables positively correlated with measurement frequency included the presence or absence of a pediatric intensivist, and whether the institution was a children's hospital or not. Variables negatively correlated with measurement frequency included larger ICUs and house officers assigned to the ICU.

CONCLUSIONS

Although measurement frequency is associated with unit-level factors, their contribution to the overall variability is small and unlikely to influence the accuracy or reliability of the PRISM score. It is unlikely that there are routine biases associated with differences in measurement frequency of PRISM variables within the spectrum of care practices that now exist.

Relationship of asymptomatic bacteriuria and renal scarring in children with neuropathic bladders who are practicing clean intermittent catheterization

OBJECTIVE

To determine whether untreated asymptomatic bacteriuria is associated with renal scarring in children with neuropathic bladders managed with clean intermittent catheterization (CIC).

DESIGN

Retrospective study of 207 patients aged 1 to 30 years (mean 11.9 +/- 5.5 years) treated with CIC for a mean duration of 6.6 +/- 3.9 years by the spina bifida program at Children's National Medical Center. All patients were examined for renal scarring with dimercaptosuccinic acid (DMSA) renal scans. Catheterized urine cultures were obtained annually, but bacteriuria ( > 10,000 colony-forming units of a single organism per milliliter) was treated only if the patients had symptoms or if vesicoureteral reflux (VUR) was present.

RESULTS

Of 207 children, 176 (85%) had one or more episodes of untreated asymptomatic bacteriuria and 72 (35%) had one or more febrile episodes associated with positive urine culture results. Biannual DMSA scans detected 54 new scarring episodes in 42 patients. Of newly recognized scars, 55% were preceded within 1 year by a febrile infection, 26% were detected in patients with VUR and asymptomatic bacteriuria, and 19% were detected in new patients during their initial examination. Univariate analysis revealed that new scarring was present in 35 of 176 patients with asymptomatic bacteriuria compared with 7 of 31 patients without (p = 809). Logistic regression analysis revealed that factors associated with scarring were febrile infections (adjusted odds ratio [OR] = 30.6, 95% confidence interval [CI] = 9.8 to 95.8), age more than 20 years (OR = 4.3, CI = 1.01 to 18.5), the presence of bladder trabeculation (OR = 2.7, CI = 1.0 to 7.6), and VUR (OR = 58.8, CI = 6.3 to 547.3), but asymptomatic bacteriuria was not associated with scarring.

CONCLUSION

In the absence of VUR, asymptomatic bacteriuria in patients undergoing CIC is not a significant risk factor for scarring and does not require antibiotic therapy.

Indications for echocardiography in the diagnosis of infective endocarditis in children

The role of transthoracic echocardiography as a diagnostic tool in children suspected of having infective endocarditis (IE) has not been defined. We hypothesized that echocardiography is only useful in children in whom there is high clinical suspicion of IE based on physical examination findings or persistently positive blood cultures. Echocardiographic reports and medical records of all inpatients (n = 133) from 1990 to 1992 who underwent echocardiography for suspected IE were reviewed. Fifty-nine of the 133 patients (44%) identified had either persistently positive blood cultures (n = 48), physical examination findings of IE (n = 20), or both (n = 9). The echocardiogram was positive in 7 of these patients (12%) and negative in all 74 patients without positive physical findings or positive blood cultures (p = 0.003). A new or changing precordial murmur, embolic phenomena, congestive heart failure, mechanical ventilation, and positive blood cultures were predictive of positive echocardiograms for IE by univariate analysis. The presence of fever, immune deficiency, and central lines, alone or in combination, was not predictive of a positive echocardiogram. In the absence of physical findings or persistently positive blood cultures, echocardiography is a low-yield study and is unlikely to aid in the diagnosis of IE in children.

Impact of quality-of-care factors on pediatric intensive care unit mortality

OBJECTIVE

To determine the importance of the following care factors previously associated with hospital quality on survival from pediatric intensive care: size of the intensive care unit (ICU), medical school teaching status of the hospital housing the ICU, specialist status (pediatric intensivist), and unit coordination.

DESIGN

After a national survey, consecutive case series were collected at 16 sites randomly selected to represent unique combinations of quality-of-care factors.

SETTING

Pediatric ICUs.

PATIENTS

Consecutive admissions to each site.

MAIN OUTCOME MEASURE

Patient mortality adjusted for physiologic status, diagnosis, and other mortality risk factors.

RESULTS

There were 5415 pediatric ICU admissions and 248 ICU deaths. The ICUs differed significantly with respect to descriptive variables, including mortality (range, 2.2% to 16.4%). Analysis of risk-adjusted mortality indicated that the hospital teaching status and the presence of a pediatric intensivist were significantly associated with a patient's chance of survival. The probability of patient survival after hospitalization in an ICU located in a teaching hospital was decreased (relative odds of dying, 1.79; 95% confidence interval [CI], 1.23 to 2.61; P = .002). In contrast, the probability of patient survival after hospitalization in an ICU with a pediatric intensivist was improved (relative odds of dying, 0.65; 95% CI, 0.44 to 0.95; P = .027). Post hoc analysis indicated that the higher severity-adjusted mortality in teaching hospitals may be explained by the presence of residents caring for ICU patients.

CONCLUSION

Characteristics indicative of the best overall hospital quality may not be associated, or may be negatively associated, with quality of care in specialized care areas, including the pediatric ICU.

Seizure control following tumor surgery for childhood cortical low-grade gliomas

Detailed preoperative electroencephalographic (EEG) studies are now recommended for children with seizures and cortical tumors to define seizure foci prior to surgery. To develop a historical perspective for better evaluation of results from series reporting tumor removal combined with resection of seizure foci, the authors reviewed seizure outcome in 60 children with seizures and low-grade neoplasms treated consecutively since 1981 by surgical resection without concomitant EEG monitoring or electrocortical mapping. Forty-seven of the 60 tumors were totally or near-totally resected; 45 patients were seizure-free and two were significantly improved 1 year following surgery. Of the 50 children in this series with more than five seizures prior to surgery, 36 were seizure-free, two were significantly improved, and 12 were not improved. Factors associated with poor seizure control included a parietal tumor location, a partial tumor resection, and a history of seizures for more than 1 year prior to surgery. The children at highest risk for poor seizure control at 2 years had experienced seizures for more than 1 year prior to surgery and had undergone partial resection of their parietal low-grade glial tumors or gangliogliomas. In contradistinction, the best seizure control was seen in patients with totally resected low-grade gliomas or gangliogliomas who had experienced seizures for less than 1 year (concordance rates for being seizure-free ranged from 78% to 86%). Long-term seizure control remained excellent. These results suggest that seizure control can be obtained 2 years following tumor surgery in the majority of children with presumed tumors after extensive tumor resection without concomitant EEG monitoring or electrocortical mapping.

Recombinant alpha-interferon therapy in multiple myeloma

Three patients with multiple myeloma were treated with recombinant alpha-interferon (r IFN-alpha 2b Intron AR) along with combination chemotherapy i.e. melphelan and prednisolone. In one case it was given as an initial therapy, while the other two patients had refractory and relapsing disease respectively. IFN-alpha 2b was given in the dose of 2 x 10(6) Mu/m2 by subcutaneous injection thrice in a week for six months in two patients and for three months in one patient. All three patients experienced improvement in bone pains; partial response with reduction in the paraprotein level was seen in one patient; while there was no radiological, biochemical or haematological improvement in two patients. Side effects noted were flu like syndrome in all three patients and urticaria in one patient. They were treated symptomatically and did not require cessation of interferon therapy.

Trends in cigarette smoking in the United States. The changing influence of gender and race

Trends in the prevalence, initiation, and cessation of cigarette smoking are reported for the US population using weighted and age-standardized data from seven National Health Interview Surveys (1974 to 1985). The decline in prevalence was linear, with the prevalence for men decreasing at 0.91 percentage points per year to 33.5% in 1985 and the prevalence for women decreasing at 0.33 percentage points per year to 27.6% in 1985. For whites the rate of decline (percentage points per year) was 0.57, to 29.4% in 1985, and for blacks the decline was 0.67, to 35.6% in 1985. Smoking cessation increased among all gender-race groups from 1974 to 1985, with the yearly rate of increase (in percentage points per year) about equivalent for blacks (0.75) and whites (0.77), while it was higher in women (0.90) than in men (0.67). Smoking initiation decreased among young men (-1.03), while it remained about the same in young women (+0.11). Initiation decreased at a more rapid rate in blacks (-1.02) than in whites (-0.35). We conclude that smoking prevalence is decreasing across all race-gender groups, although at a slower rate for women than men, and that differences in initiation, more than cessation, are primarily responsible for the converging of smoking prevalence rates among men and women.

Donor-specific transfusions. Donor-recipient HLA compatibility, recipient HLA haplotype, and antibody production

HLA profiles of 25 donor-specific transfusion (DST) kidney donor-recipient pairs were analyzed for HLA antigen compatibility. Serum samples collected during and after DST were tested for cytotoxic antibodies against T and B lymphocytes of the donors and 30 normal individuals. Eleven recipients did not produce cytotoxic antibodies to the antigens of their DST donors, and eight produced cold and/or warm, broadly reactive B-cell antibodies. Six patients (24%) produced HLA-A, B, C, and/or DR antibodies. Three of these individuals produced antibodies after two immunizations, while others required three immunizations. Three of the 11 antibody nonproducers (17%) had not received previous transfusions, as compared to three of the eight antibody producers (43%). Comparison of HLA profiles revealed 22 percent of the HLA-A, B, DR identities between the transfusion donor and recipient in antibody nonproducers as compared to 9 percent of the HLA-A, B, DR identities in antibody producers. The HLA-A2, B40, DR4 haplotype and HLA-DRW6 antigen were more common among antibody producers than among nonproducers, who had an excess of the HLA-B8, DR3 haplotype. These results are consistent with the hypothesis that there may be high- and low-responder HLA haplotypes that control immunologic responsiveness to histocompatibility antigens.

The human sex ratio: increase in first-born males to parents with shared HLA-DR antigens

Maternal-fetal HLA-DR antigen sharing has been reported to affect the sex ratio of first-born. We therefore studied offspring sex ratios and birth orders in 66 families in which parents shared one or more HLA-DR antigens as compared to 61 families with no parental HLA-DR sharing. A significant excess of males was found among first-born children who were HLA-DR compatible with their mothers compared to first-born HLA-DR incompatible children of couples sharing HLA-DR antigens and couples not sharing HLA-DR antigens. Increased numbers of males may persist among children of higher birth orders in families where parents share both HLA-DR antigens, but not among couples sharing only one HLA-DR antigen. We hypothesize that the presence of the H-Y antigen in the male fetus may provide the necessary stimulus for a successful pregnancy in HLA-DR compatible pregnancies and may explain the excess of male births in the general population.

Factors responsible for successful HLA-DR typing of mononuclear cells from cord blood

Of 115 cord blood samples tested, both HLA-DR antigens were identified in 79% of fresh samples, 66% of older samples and 55% of freshly frozen samples. Because of weak reactions, one or two questionable antigens were present in 21% of fresh samples as compared to 34% of older samples and 45% of freshly frozen samples. Older samples showed lower cell viability, more extra reactions, and a high frequency of weak reactions. Comparison of cord blood DR antigens with parental DR antigens revealed that antigens were missed or inappropriately assigned in 5 known cases. This was more frequent with older blood samples. The critical factors in successful DR typing of cord blood samples were 1) dilution of cord blood samples with medium, 2) processing of the samples as soon as possible, and 3) overnight incubation to remove adherent cells.

Synthesis of carbon-13-labeled tetradecanoic acids

The synthesis of tetradecanoic acid enriched with 13C at carbons 1, 3, or 6 is described. The label at the carbonyl carbon was introduced by treating 1-bromotridecane with K13CN (90% enriched) to form the 13C-labeled nitrile, which upon hydrolysis yielded the desired acid. The [3-13C]tetradecanoic acid was synthesized by alkylation of diethyl sodio-malonate with [1-13C]1-bromododecane; the acid was obtained upon saponification and decarboxylation. The label at the 6 position was introduced by coupling the appropriately labeled alkylcadmium chloride with the half acid chloride methyl ester of the appropriate dioic acid, giving the corresponding oxo fatty acid ester. Formation of the tosylhydrazone of the oxo-ester followed by reduction with sodium cyanoborohydride gave the labeled methyl tetradecanoate which, upon hydrolysis, yielded the desired tetradecanoic acid. All tetradecanoic acids were identical to unlabeled analogs as evaluated by gas-liquid chromatography and infrared or NMR spectroscopy. These labeled fatty acids were used subsequently to prepare the correspondingly labeled diacyl phosphatidylcholines.

Effect of bleomycin-radiotherapy combination in management of head and neck squamous cell carcinoma

Twenty-five patients with head and neck squamous cell carcinoma were treated with bleomycin-radiotherapy protocol, 15 mg bleomycin I.V. on alternate days followed by radiation within half an hour. The average total dose of bleomycin was 150 mg. Radiotherapy was given daily. Two patients were lost to follow-up very early in the course of the treatment and were removed from the study for statistical purposes. Thirty-six patients with head and neck squamous cell carcinoma who were treated with radiotherapy alone during the same period were used as controls. The patients were followed for two years. The incidence of response rate did not differ significantly between regimens; however the incidence of side effects with bleomycin-radiotherapy, 82.61%, is significantly more than that of radiotherapy alone (52.78%). Median survival time (MST) of those responding to bleomycin-radiotherapy protocol was seven months and 12 days and for radiotherapy responders was six months. Neither the response rate nor the MST improve significantly after pretreatment with bleomycin. On the contrary, the incidence of side effects increased significantly.

Triamterene nephrolithiasis complicating dyazide therapy

A case of triamterene nephrolithiasis is reported in a man after 4 years of hydrochlorothiazide-triamterene therapy for hypertension. The stone passed spontaneously and was found to contain a triamterene metabolite admixed with uric acid salts. Factors affecting triamterene nephrolithiasis are discussed and 2 previously reported cases are reviewed.

Granulomatous hepatitis due to Mycobacterium scrofulaceum: report of a case

A rare case of hepatic granulomatosis due to Mycobacterium scrofulaceum is presented. The prolonged clinical course before liver biopsy was characterized by a disproportionate rise in alkaline phosphatase, moderate hepatomegaly, tiredness, and low-grade fever. Liver biopsy confirmed primary liver granulomatosis in the absence of evidence of pulmonary or systemic involvement. The patient was treated with INH, rifampin, and cycloserine with amelioration of clinical symptoms and return of serum alkaline phosphatase levels to normal.

Evaluating statistical analyses and reproducibility of microbial mutagenicity assays

The NCI/NTP has completed the first phase of a 4-laboratory study on the reproducibility of testing chemicals for mutagenicity in the Salmonella/microsome assay. This paper is a report of the statistical analysis of some of that data. This analysis involved (1) identifying and removing spurious data; (2) determining the adequacy of the remaining data in making a decision on the mutagenicity of the test chemical; (3) performing the statistical tests; and (4) interpreting the results. Using this procedure, 7 approaches were used to determine the mutagenicity of a test. These approaches were the (1) 2-fold rule, (20 modified 2-fold rule, (3) one-way analysis of variance (homogeneity test), (4) test for linear trend, (5) combination of 3 and 4, (6) 97.5th percentile threshold rule and (7) confidence interval threshold rule. The conclusions drawn by each rule were compared to the microbiologists' interpretation, and the results of these comparisons were presented. In addition, the strengths and weakness of each rule were discussed. The reproducibility of the assay in this study was examined, and a discussion of the significance of these results was presented.

Biophysical properties of a major membrane phospholipid, dielaidoylphosphatidylethanolamine, found in an Escherichia coli fatty acid auxotroph

Dielaidoylphosphatidylethanolamine, a principal lipid component of membranes of Escherichia coli fatty acid auxotrophs enriched in elaidic acid, has been studied by paramagnetic resonance, fluorescence, and calorimetric methods. EPR measurements with perdeutero-di-tert-butylnitroxide and 2,2,6,6-tetramethyl piperidine-1-oxyl indicate that, when dispersed in aqueous media, this phospholipid undergoes an abrupt order leads to disorder transition at 37.5 degrees C and 36.5 C, respectively. A similar transition temperature is suggested by experiments with 9-doxyl-dimyristoylphosphatidylethanolamine (DEPE). cis- and trans-Parinaric-acid fluorescence polarization measurements indicate that the midpoint of this transition occurs at 34.0 degrees C and 35.5 degrees C, respectively. Differential scanning calorimetry of DEPE revealed a single, sharp endotherm at 38.5 degrees C with increasing temperature; two exotherms of similar magnitude were observed at 36.5 degrees C and 34.5 degrees C upon cooling. This double transition was not observed by any of the other methods. From these results we conclude that the major structural transition at 30-31 degrees C observed previously with 5-, 12-, and 16-doxyl stearate in intact E. coli membranes is due to the DEPE present (Morrisett, J.D., Pownall, H.J., Plumlee, R.T., Smith, L.C., Zehner, Z.E., Esfahani, M., and Wakil, S.J. (1975) J. Biol. Chem. 250, 6969-6976).

A convenient synthesis of phosphatidylcholines: acylation of sn-glycero-3-phosphocholine with fatty acid anhydride and 4-pyrrolidinopyridine

A high-yield synthesis of saturated, unsaturated, and short chain phosphatidylcholines from sn-glycero-3-phosphocholine is described. The procedure offers advantages over other reported procedures for the synthesis of phosphatidylcholine in that the large-scale synthesis and purification can be achieved in a minimum time. The procedure utilizes 4-pyrrolidinopyridine as a catalyst and moderate amounts of fatty acid anhydride (2 mol eq. of fatty acid anhydride per mol of OH) in a 1:1 mixture of benzene-dimethylsulfoxide (DMSO) at 40 degrees--42 degrees C (oilbath) for 2--5 hr. At the end of the reaction, the phosphatidylcholine can be purified in the usual manner or by using a Waters Prep LC/500 with a radially compressed silica gel column eluted with chloroform-methanol-water 60:30:4. At a flow rate of 200 ml/min, the phospholipid elutes in 10--15 min, depending on the chain length and unsaturation.

Antimicrobial activity of chlormerodrin

A radiochemical study for antimicrobial activity of chlormerodrin was performed using some commonly occurring nonpathogenic and pathogenic microorganisms. Chlormerodrin concentrations of 15-35 and 20-45 microgram/ml of the culture medium were microbiostatic and microbicidal, respectively. The microbiostatic effect was reversible in the presence of cysteine, an amino acid containing a sulfhydryl group.

Structure of some cyclohexyl compounds as related to their ability to stimulate plant growth

Aqueous solution, 10 mm, of cyclohexanecarboxylic, cyclohexylacetic, cyclohexylpropionic, cyclohexylbutyric acids (all components of naphthenic acid); cis-1,2-, and trans-1, 4-cyclohexyldicarboxylic acids; 3-cyclohexene-1-carboxylic and cyclohexylsulfamic acids; and cyclohexyl mercaptan were applied to 14-day-old bush bean plants, Phaseolus vulgaris L. cv. Top Crop. Only cyclohexanecarboxylic and cyclohexylacetic acid resulted in a statistically significant (P = 0.05) increase in pod production per plant in all experiments. The stimulation by the first four monocarboxylic acids decreased as the number of methylene groups in the side chain increased from 0 to 3. The effective compounds possessed an H-saturated 6-carbon ring with a single carboxyl group attached directly to the ring or separated from it by no more than one methylene group.

Intraperitoneal blood transfusion in African adults with hookworm anaemia

Twenty-nine patients were given an intraperitoneal transfusion of blood. The procedure was found to be free of serious complications. Study of the absorption of an (51)Cr-labelled cells from the peritoneum in 14 patients showed that between 35 and 100% of the blood was absorbed intact in 6 to 10 days. Intraperitoneal transfusion may be indicated as an alternative or as an addition to exchange transfusion in severe hookworm anaemia.