CLINICAL EVALUATION OF THE AUGMENTED DELTA QUOTIENT MONITOR FOR INTRAOPERATIVE ELECTROENCEPHALOGRAPHIC MONITORING OF CHILDREN DURING SURGERY AND CARDIOPULMONARY BYPASS FOR REPAIR OF CONGENITAL CARDIAC DEFECTS

To assess the augmented delta quotient (ADQ) monitor as a monitorof cerebral function during cardiac surgery, we monitored duringoperation the electroencephalograms of 48 young subjects (aged2 weeks to 19 yr). We found ADQ patterns produced by cardiopulmonarybypass, hypothermia and general anaesthetic agents correlatedwith those obtained from a compressed spectral array (CSA) monitorand could be differentiated from changes caused by cerebralischaemia, except in the youngest group of patients ( 18 months)undergoing deep hypothermia (19.4 (SD 0.8) °C nasopharyngeal).In all other age groups the ADQ proved to be a simple monitorof the adequacy of cerebral perfusion. Neurological deficitoccurred only if the ADQ was abnormal during hypotension fora period exceeding 7 min. ADQ evaluation of cerebral functionwas limited by events which produced artificially normal ADQreadings such as low amplitude EEG activity and the describedisoflurane effect that was demonstrated to occur in some cardiacpatients. The results obtained by the ADQ were comparable tothose obtained by compressed spectral array and the ADQ waseasier to use and interpret. ^*Present address: Department of Anaesthesia and Intensive Care,Basingstoke District Hospital, Basingstoke, Hants.     

A Two-Generation Reproduction Study in Rats Receiving Diets Containing Hexamethylenediamine

A Two-Generation Reproduction Study in Rats Receiving DietsContaining Hexamethylenediamine. SHORT, R. D., JOHANNSEN, F.R., AND SCHARDEIN, J. L. (1991). Fundam. Appl. Toxicol. 16,490–494. Rats received diets containing average dailydoses of 0, 50, 150, and 500 mg/kg/ day of hexamethylenediamineover two generations. Although no treatment-related mortalitywas observed in any of the groups, the weight gain of adultsand pups was slightly reduced in the high dose group. Whilethe litter size was also slightly reduced at birth in the highdose group, there was no adverse effect on survival during lactationin any of the treated groups. Thus, the dietary administrationof up to 150 mg/kg/day of hexamethylenediamine over two generationsdid not adversely affect reproduction or fertility in rats.     

A New Variant of Hereditary Hemolytic Anemia With Stomatocytosis and Erythrocyte Cation Abnormality

A new variant of congenital hemolyticanemia associated with stomatocytosis,reticulocytosis, decreased osmotic fragility, type I autohemolysis and shortened erythrocyte survival without specific splenic sequestration was discoveredin three siblings of Swiss-German ancestry. Increased intracellular sodium(two to three times normal) and slightlydecreased intracellular potassium weredetected. Total sodium efflux was eight-fold greater than normal but total potassium influx was normal and ouabain-sensitive potassium influx was decreased.The ouabain-sensitive sodium efflux:potassium influx ratio was 26:1 ratherthan the 3:2 ratio noted in normal cells.The consanguineous parents, four othersiblings, and 44 other family membershad mild stomatocytosis, reticulocytosis,and, when studied, decreased osmoticfragility, increased autohemolysis, intermediate abnormalities of cation content,cation flux, and moderate shortening oferythrocyte survival. Autosomal dominant inheritance was suggested. Noabnormalities of RBC enzymes, hemoglobin or lipids were observed. No abnormalities of membrane protein weredetected on acrylamide gel. Substratedepletion of these hypermetabolic cellsresulted in intracellular dehydrationwith potassium loss in excess of sodiumgain and decreased deformability. Although the exact nature of the defectresponsible for hemolysis is unknown,this syndrome differs from other hereditary hemolytic anemias associated withstomatocytosis.

Submitted on December 21, 1970 Revised on March 16, 1971 Accepted on March 29, 1971     

Stem Cell Migration and Proliferation During Severe Anemia

The pluripotential stem cell (CFU) compartment of marrow and spleen wasevaluated in mice subjected to an intense erythroid stimulus associated withphenylhydrazine-induced anemia. Erythroid hyperplasia occurred in both marrow and spleen. CFU in the marrowgradually declined to approximately 50per cent of control levels (day 5) whiletheir numbers in the spleen increased(fourfold) by day 3 and were maintainedat this level for several days. Thesechanges in numbers of marrow andsplenic CFU were not associated withCFU proliferation. Thereafter, CFU inthe marrow, but not in the spleen, entered active cell cycle. The data suggestthat CFU migrate from marrow to spleenduring the demands of severe anemia.The induction of marrow CFU into cyclefurther suggests a negative feedback,which, perhaps through cell-cell interaction, maintains stem cells at a criticalcompartment size. The failure of splenicCFU to cycle may reflect the converseeffect, i.e. an inhibition on stem cell proliferation in the wake of an expandedstem cell pool.

Submitted on March 17, 1970 Revised on May 14, 1970 Accepted on June 9, 1970     

Polymerization Depths of Contemporary Light-Curing Units Using Microhardness

Purpose: This research investigated composite depths of cure using a variety of light‐curing units and exposure protocols. Materials and Methods: Composite (Herculite XRV, shade A2, Kerr, Orange, California) was exposed in opaque compules to conventional quartz tungsten halogen (QTH) units, soft‐start units, high‐intensity QTH and plasma arc (PAC) curing lights, and one argon laser. Cured compules were sonicated to remove uncured composite and were sectioned and polished along the long axis to expose cured composite. Knoop hardness was measured 0.5 mm from the irradiated, top surface and then at 1.0 mm and in 1.0‐mm increments until reliable readings could no longer be obtained. Hardness values were compared by analysis of variance at similar depths within a specific curing‐light classification, using the hardness of the standard 40‐second conventional QTH exposure as comparison (Dunnett's t‐test). Depth of cure was defined as the deepest hardness value found equivalent to that at 0.5‐mm depth for a specific curing light and scenario. Results: Conventional QTH lights provided similar hardness profiles. At 2‐mm depth, use of a different unit or curing tip made no difference in hardness compared with the standard. At this depth, soft‐start (pulse‐delay and step‐cure) methods yielded hardness similar to that of the standard. High‐intensity QTH lights provided similar hardness at 2‐mm depth in 10 seconds to that of the standard 40‐second exposure. Plasma arc exposure for less than 10 seconds produced inferior hardness compared with the standard. A 10‐second PAC and a 5‐second laser exposure gave hardness at 2‐mm depth equivalent to that of the 40‐second standard. Depth of cure for almost all curing scenarios was not greater than 2 mm. CLINICAL SIGNIFICANCE Similar‐type conventional QTH lights with different tip diameter (8 and 12 mm) provide similar composite cure characteristics. Soft‐start techniques provide similar cure profiles to those achieved with conventional QTH technique when used according to manufacturer's recommendations. High‐intensity QTH units and the argon laser can reduce exposure time while providing composite with similar hardness to that of conventional QTH curing. Plasma arc exposure should be at least of 10 seconds duration to provide hardness equivalent to that achieved with conventional 40‐second QTH exposure. Even with consideration of high‐intensity curing units, composite increments should still be no greater than 2 mm to provide homogeneous hardness.     

PRELIMINARY RESULTS OF A RANDOMIZED TRIAL OF ADJUVANT IMMUNOTHERAPY IN PATIENTS WITH MALIGNANT MELANOMA WHO HAVE LYMPH NODE METASTASES

This study evaluates the effect of adjuvant immunotherapy with BCG alone, or combined with melanoma cell vaccine, on the recurrence and survival rates of patients with metastatic melanoma in the regional lymph nodes who were treated by lymphadenectomy. Patients were prospectively randomized and stratified on the basis of age, sex, site of primary tumour, and clinical estimate of the regional nodes. During the past four years, 134 patients were entered into this trial, and to date, the incidence of recurrence among the two arms mentioned and the control arm is not significantly different; however, patients receiving BCG alone had longer survival than those in either the tumour cell vaccine or control groups. The improved survival in the BCG-only group was found to be due to the fact that patients survived longer with their recurrent disease than the patients in the other two groups. At the present time, these differences do not appear to be significant enough to justify routine adjuvant immunotherapy in patients with melanoma metastatic to regional nodes. Longer follow-up will be necessary to evaluate the role of adjuvant immunotherapy of Stage II melanoma.     

Smoking patterns at a British and at an American medical school

Cigarette smoking among medical students at the University of Bristol (Bristol) and the New York University School of Medicine (NYU) was investigated and differences were subjected to statistical analysis.
At Bristol 34–6% and at NYU 14–3% of respondents classified themselves as regular smokers. Among students in the pre-clinical phase of training the difference between the number of smokers at Bristol and at NYU was not significant. At both schools more clinical students smoked than preclinical students, but only at Bristol did the difference between the number of smokers in the two grade levels reach statistical significance.
There are fewer heavy smokers (consumers of more than twenty cigarettes per day) among the pre-clinical students at Bristol than among preclinicals at NYU. In the clinical year, however, there were slightly (insignificantly) fewer heavy smokers at NYU while there were significantly more at Bristol.
Smokers at NYU acquired the habit at a somewhat earlier age than the smokers at Bristol.
The majority of students at both schools indicated that medical education had not influenced their decision to smoke or not to smoke.
Most smokers—more among the clinical than the pre-clinical students—reported that they were displeased with their habit and that they wished to give it up. Somewhat fewer smokers at Bristol gave that response than students at NYU.
Factors contributing, at least in part, to the differences between smoking patterns observed may be variables of age and years of education.
The widely held but untested belief that precept and example by medical school teachers may be a potent force for modifying the smoking behaviour of health professionals, is in need of research.     

DFP Labeling of Platelets During Recovery from Thrombocytopenia

Rat platelets were labeled with tritiated diisopropylfluorophosphate(³H-DFP) during recovery from acute thrombocytopenia. The results indicated that there was significant labeling of megakaryocytes by ³H-DFPwhich, in the presence of an increased rate of platelet production, resulted inmaintenance of relatively constant values for platelet-bound radioactivity during the period of maximum platelet production and reactive thrombocytosis.Significant random loss of platelets was apparent, and, when a cohort ofyoung platelets was transfused to normal recipients, they were destroyed at anormal rate.