Phrenic nerve injury during coronary artery bypass

After coronary artery bypass, some patients have diaphragmatic elevation, usually on the left side. To test our hypothesis that this phenomenon is due to phrenic nerve injury resulting from either 1) dissection of the proximal portion of the left internal mammary artery or 2) topical cooling of the heart with icy slush, we performed the following 2-part study. First, we reviewed our hospital records of 99 coronary artery bypass patients, 55 of whom had received left internal mammary artery grafts and 44 of whom had undergone saphenous vein grafting; the results showed no significant difference between the rates of left-sided diaphragmatic paralysis in the 2 groups (47% versus 41%, respectively). Next, we performed a prospective, randomized study in 100 consecutive patients, using a cardiac insulation pad to protect the left phrenic nerve in 58 patients and using no protective pad in 42 patients. At the time of hospital discharge, left-sided diaphragmatic elevation was seen in 6 (10.3%) of the 58 patients in whom insulation had been used and in 19 (45.2%) of the 42 patients whose phrenic nerve had been unprotected (p < 0.001). We conclude that cooling of the left phrenic nerve with icy slush in the pericardial cavity causes left-sided diaphragmatic paralysis and that the frequency of this injury can be reduced if a cardiac insulation pad is placed between the nerve and the icy slush.

Effects of exercise tolerance, age, and gender on the specificity of radionuclide angiography: sequential ejection fraction analysis during multistage exercise

We investigated the factors that determine the left ventricular ejection fraction response to exercise in 57 middle-aged, untrained patients with angiographically normal coronary arteries. The ejection fraction was measured by blood pool radionuclide angiography during each stage of exercise. Stepwise regression analysis was applied to 39 variables, and the resulting significant variables were then included in a logistic regression model to determine which of them would predict a normal ejection fraction response. By stepwise regression analysis, the best model (F = 5.6, p = 0.0004) was obtained by combining four variables: achieving 85% of maximal predicted heart rate, peak heart rate, number of exercise stages performed, and resting pulse pressure. Only the latter two variables were significant by logistic regression analysis. The specificity of greater than or equal to 5 ejection fraction unit increase at peak exercise was 42%, 75%, and 100% in patients who exercised one, two, or three stages, respectively. Furthermore, the increase in ejection fraction during each exercise stage was independent of age or gender. Thus the standard criteria of normality during exercise radionuclide angiography have high specificity only when applied to patients with good exercise performance, regardless of age or gender.

Should it be parietal cell vagotomy or selective vagotomy-antrectomy for treatment of duodenal ulcer? A progress report

This is a progress report of a prospective, randomized study involving 200 consecutive patients treated electively with either parietal cell vagotomy (PCV) or selective vagotomy and antrectomy (SV-A). Both groups comprised patients with pyloric, prepyloric, or duodenal ulcers. There was no operative mortality in either group. Patients were examined at 2, 6, 12 months, and every 12 months thereafter for 8-10 years. The two operations produced no statistical difference in the frequency of diarrhea. Dumping (p less than 0.0005) and weight loss (p less than 0.0005-p less than 0.05) were statistically less after PCV than after SV-A. There were two recurrent ulcers (2.2%) after SV-A. One was treated successfully by medical therapy and one patient suspected of having gastrinoma had total vagotomy. Nine patients had recurrent ulcers in the PCV group for an accumulated recurrence rate of 10.1% at 10 years by life-table analysis. There was a significant difference (p less than 0.033) between the curves for recurrent ulcers in the two groups of patients. The recurrent ulcer rate after PCV was 21% for patients with pyloric and prepyloric ulcers and 6% for patients with duodenal ulcer. There was no significant difference between the recurrent ulcer rate for PCV and SV-A if the patients with pyloric and prepyloric ulcers were withdrawn from the study. Of the nine patients with recurrent ulcers in the PCV group, three had an inadequate vagotomy and four had a pyloric or prepyloric ulcer before operation. Three patients were successfully treated with antrectomy. Five patients were treated successfully by medical therapy and remained healed for long periods without recurrence. One patient had five recurrences. He declined operation and remained free of symptoms for 3 years after his last recurrence. Poor gastric emptying necessitated gastroenterostomy in five patients in the SV-A group and in one patient in the PCV group. Patients' clinical results were evaluated according to a simple Visick grading scale. A significantly (p less than 0.0005) greater number of patients were in Visick I category after PCV than after SV-A. The clinical results obtained with PCV make this the operation of choice for the elective surgical treatment of duodenal ulcers even though the results obtained with SV-A were good.

Age-related reductions in cerebral vasomotor reactivity and the law of initial value: a 4-year prospective longitudinal study

A group of 51 neurologically normal, middle-aged and elderly volunteers (aged 35-86 years; mean age 63.24 years) with and without risk factors for stroke were given annual tests of cerebral vasomotor reactivity to assess any changes in the cerebral vascular capacitance associated with advancing age that might alter cerebral vasomotor reactivity. Cerebral vasomotor reactivity was estimated as the difference in bihemisphere gray matter CBF measured by the 133Xe inhalation method in the steady state breathing room air, followed by a second measurement during inhalation of 100% oxygen. There were significant and progressive reductions in cerebral vasomotor reactivity during the 4-year longitudinal study. Positive linear correlations were apparent between initial steady-state mean bihemisphere gray matter CBF levels and degrees of vasomotor reactivity, suggesting that the Law of Initial Value plays an important role. This should be borne in mind when analyzing scores of cerebral vasomotor reactivity. In the present communication, analysis of covariance was used to correct for influences of initial CBF levels on vasomotor responses tested while breathing pure oxygen.

Sleep-Related Electrodermal Activity Patterns in Impotent Patients

The etiology of erectile failure is not always clear despite the fact that recordings of nocturnal penile tumescence (NPT) are used to detect patients with a significant organic component to their complaint. We recorded electrodermal activity in addition to NPT in 60 impotent patients. Normally more electrodermal activity occurs in stage 2 than in stage REM sleep. Despite a similar total amount of electrodermal activity, organically impotent patients tended to have less electrodermal activity in stage 2 and more in stage REM sleep than those with normal NPT. This difference was due to a subgroup of 15 organically impotent patients with less electrodermal activity in stage 2 than in stage REM sleep. Because of this difference in the pattern of electrodermal activity in relation to sleep stages, the results suggest a central nervous system change is related to impaired erectile capability and abnormal NPT in these cases.

The effects of chronic cigarette smoking on cerebrovascular responsiveness to 5 per cent CO2 and 100 per cent O2 inhalation

Effects of chronic cigarette smoking on cerebrovascular responsiveness of volunteers at risk for stroke and not at risk for stroke were evaluated by serial measurements of cerebral blood flow using the 133Xe inhalation method. Resting gray matter blood flow values (Fg) measured while breathing room air were compared with Fg values measured during inhalation of either 5 per cent CO2 in air or 100 per cent O2. Changes in Fg values during inhalation of 5 per cent CO2 were used to estimate cerebral vasodilator capacitance, and those during inhalation of 100 per cent O2 were used to estimate cerebral vasoconstrictor capacitance. Results indicated that chronic cigarette smokers have both reduced vasodilator (P less than 0.01) and reduced vasoconstrictor (P less than 0.02) capacitance when compared with nonsmokers of the same ages regardless of whether or not other risk factors for stroke were present. Vasodilator capacitance to 5 per cent CO2 inhalation was reduced among smokers compared with nonsmokers of the same age by 48 per cent in non-risk subjects and 56 per cent in risk-factored subjects, while vasoconstrictor capacitance to 100 per cent O2 inhalation among smokers was decreased by 24 per cent in non-risk subjects and 34 per cent in risk-factored subjects. In risk-factored subjects, combined effects of smoking and other risks appeared to be additive.

Dose-related effects of phenobarbitone on human sleep-waking patterns

1 Twenty-four healthy male subjects had two consecutive drug nights at 2-week intervals using placebo and 80, 140 and 240 mg doses of phenobarbitone in a double-blind cross-over design. 2 Phenobarbitone produced significant dose-related decreases in sleep latency and number of awakenings, along with increased total sleep time. 3 Both subjective and objective measures of sleep indicated the presence of cumulative (first v second night) effects of phenobarbitone, especially decreases in the number of awakenings and in delta waveform activity. 4 Measures of REM sleep were highly sensitive to phenobarbitone. The high dose decreased REM density to 30% of baseline on the first night and to 18% on the second night. 5 EEG alpha activity was decreased, beta activity was increased and sigma spindle activity was unaffected by phenobarbitone during sleep. 6 Subjects experienced some impairment of cognitive performance along with residual sedation the following morning.

Dose-related effects of flurazepam on human sleep-walking patterns

Two consecutive nights of flurazepam at each of 15, 26, and 45 mg were compared to placebo in a Latin-square double-blind crossover design using 24 healthy young-adult males. Flurazepam had significant hypnotic effects on objective and subjective measures of efficacy: shorter sleep latency, longer sleep time, and fewer awakenings. It also induced morning sedation along with decrements in cognitive performance. Flurazepam had dose-related impacts on both human and computer-scored EEG-EOG parameters: less stages 3 + 4 and decreased EEG delta, less stage 1 REM and decreased REM density, more stage 2 and increased EEG spindling. Also, EEG alpha and movement artifact were decreased and EEG beta was increased. Only a few of the EEG-EOG variables and none of the subjective indices had cumulative changes on the two drug nights. Stage shifting was unaffected at the two lower doses on the first night but decreased at all three dose levels on the second night; percent stages 3 + 4 was unaffected on the first night but decreased at all dose levels on the second night. The rate of delta waveform activity was also diminished by a greater amount on the second night. This study conclusively established that flurazepam affects the EEG-EOG architecture of sleep on each of the first two nights of administration.

Lymphocyte replication in lung cancer patients undergoing radiotherapy

In vivo and in vitro survival and response of lymphocytes were studied in 12 lung cancer patients before, during and following radiotherapy, and comparisons were made to data from 20 healthy control subjects. Lymphocyte counts of lung cancer patients prior to radiotherapy did not differ significantly from those of control subjects. Following radiotherapy, lymphocyte counts were significantly reduced. The in vitro survival of lymphocytes from lung cancer patients prior to radiotherapy was lower than that of normal controls. Radiation treatment had no effect on lymphocyte survival in vitro. PHA-stimulated lymphoblast formation in lung cancer patients prior to radiotherapy did not differ from that of normal controls, but decreased significantly during radiotherapy.

Aryl hydrocarbon hydroxylase inducibility in lung cancer patients undergoing radiotherapy

Aryl hydrocarbon hydroxylase (AHH) inducibility was studied in cultured lymphocytes from 21 healthy control subjects and from 15 lung cancer patients selected for radiation therapy. AHH inducibility of the patients was measured prior to, during and at the end of radiation therapy. Four of 15 patients had values comparable to the healthy controls. Cellular DNA and protein measurements of cultured lymphocytes were the same for patients and healthy controls. There was no significant difference in the percentage of lymphoblast formation and percentage of cell survival between the two groups. Radiation therapy reduces the number of lymphocytes in vivo and the amount of lymphoblast formation in vitro. AHH inducibulity is signifcantly lowered by radiation in the patients who had very high inducibility at pre-treatment level. DNA and protein contents of cultured lymphocytes did not change during radiation therapy.

Aryl hydrocarbon hydroxylase inducibility and lymphoblast formation in lung cancer patients

Aryl hydrocarbon hydroxylase (AHH) inducibility and lymphoblast formation were studied in lymphocytes from healthy control subjects and from lung cancer patients undergoing radiotherapy. The relationship between AHH inducibility and percentage lymphoblasts was statistically significant only for the pre-treatment patients (r = 0.598; p less than 0.05). In the control group and in patients undergoing radiotherapy the correlation between AHH inducibility and lymphoblast formation was positive but statistically it was not significant. Our data do not suggest a linear relationship between AHH inducibility and lymphoblast formation.

Induction of hepatic aryl hydrocarbon hydroxylase in C57BL mice by ionizing radiation

Inbred strains of C57BL mice were exposed to either 100, 500, or 1000 rads of whole-body irradiation. Another group of mice were given injections of 3-methylcholanthrene only, and a control group had no treatment. Forty-eight hr after treatment, the animals were killed and hepatic aryl hydrocarbon hydroxylase (AHH) activity was measured by spectrophotofluorometer. A comparison of hepatic AHH activity in treated and nontreated groups of mice showed that each treated group had a significantly increased AHH induction compared with the control group. Although radiation appeared to have a dose-related effect on AHH induction, the increase with dose level was not statistically significant.

Prediction of chronicity in psychiatric patients

In order to determine the best combination of variables for predicting which patients would be released from state mental hospitals and which would be retained, the 1,500 patients examined in the course of a cross-sectional survey of the residental population of Texas state mental hospitals in 1966 were followed up in 1971. Eighteen variables were selected for discriminant analysis, comparing the patients nerver released from the hospital with those known to be current extrainstitutional residents. The stepwise program selected four variables: (1) length of prior stay; (2) relatives' attitudes toward release; (3) social adequacy; and (4) conceptual disorganization. Applying this model to the study groups, 79% were correctly classified with regard to their in hospitals/not in hospital status, suggesting that early identification of chronicity in future studies is feasible.