Diastolic left ventricular pressure-volume and stress-strain relations in patients with valvular aortic stenosis and left ventricular hypertrophy

Left ventricular (LV) chamber and myocardial stiffness were determined in 17 patients, four subjects with normal LV function and 13 subjects with valvular aortic stenosis and concentric myocardial hypertrophy, using simultaneous catheter micromanometry and LV cineangiography. Pressure (P), volume (V), and wall thickness (h) were measured. Variability in both chamber and myocardial stiffness parameters was found with five of the aortic stenosis patients (Group 1, left ventricular end-diastolic pressure = 15 +/- 2 (SEM) mm Hg) exhibiting normal values for end-diastolic dP/dV and dP/dV/V, for chamber stiffness constants (a,a') derived from P-V and normalized P-V relations, respectively, for end-diastolic myocardial elastic stiffness (ES or EE, where S = spherical model and E = ellipsoidal model) at the midwall of the minor axis circumference, and for the myocardial stiffness constants (KS or KE) of the circumferential stress-strain relation. Eight other patients with aortic stenosis (Group II, left ventricular end-diastolic pressure = 20 +/- 3 (SEM) mm Hg) exhibited significant increases in end-diastolic dP/dV,dP/dV/V,ES and EE and a tendency for increase in the chamber stiffness constants (a,a') and myocardial stiffness constants (KS, KE). These observations suggest that concentric increase in muscle mass (increase in wall thickness/minor axis radius ratio and wall volume/chamber volume ratio) is an important determinant of elevated mid- and late diastolic pressures in patients with valvular aortic stenosis, while concurrently mitigating increases in both systolic and diastolic wall stress. In some patients with aortic stenosis, however, diastolic filling pressures are elevated more severely, not only as a result of concentric hypertrophy, but also in response to augmented muscle stiffness. Reversibility of increased ventricular diastolic stiffness and elevated filling pressures was documented as concentric hypertrophy regressed post-aortic valve replacement in one patient, suggesting that fibrosis is not invariably the cause of enhanced myocardial stiffness in this secondary and compensatory form of hypertrophy.

Evaluation of the in vivo function of the Hancock porcine xenograft in the aortic position

We evaluated the vivo hemodynamic function of the stent-mounted glutaraldehyde-fixed porcine xenograft in 23 patients who had undergone aortic valve replacement from 2 days to 24 months prior to the study. Functional aortic valve orifice areas for the porcine xenograft ranged from 0.58 to 3.0 sq. cm., the average area being 1.36 sq. cm. Six patients had calculated prosthetic valve orifice areas less than 1.0 sq. cm. Valve orifice area did not correlate significantly with valve size or the time interval from surgery to postoperative study. Left ventricular stroke volume showed a significant, positive correlation with calculated xenograft orifice area. Systemic thromboembolism was not encountered. One patient required reoperation for xenograft stenosis caused by dense fibrin deposition on the aortic leaflets. We conclude that use of the stent-mounted glutaraldehyde-fixed porcine xenograft can be associated with significant functional stenosis which may be related to annulus size or inertial properties of the valve. These factors should be taken into consideration when considering use of the stent-mounted glutaraldehyde-fixed porcine xenograft in individual patients.

Mechanism of action of the cro protein of bacteriophage lambda

The mechanism of action of cro protein was probed by measuring its ability to protect DNA against methylation by dimethyl sulfate and its effect on transcription in vitro. The cro protein binds to the same three sites in the right operator (OR) of bacteriophage lambda DNA as does the lambda repressor. Dimethyl sulfate protection experiments reveal major groove contacts for both proteins, and cro protein protects from methylation a subset of those purines protected by lambda repressor. These experiments also show that the relative affinity of these two proteins for the three operator sites is different: whereas lambda repressor binds with an affinity OR1 greater than OR2 greater than OR3, the order for cro protein is OR3 greater than (OR1, OR2). As predicted by these results, cro protein, like the lambda repressor, blocks in vitro transcription of cI and cro from the two divergent promoters that overlap OR. Also as predicted, transcription of cI is turned off at lower cro protein concentrations than is transcription of cro, whereas the opposite order of repression is obtained with lambda repressor. These results describe the molecular mechanism of cro protein action and show that two regulatory proteins can bind to the same three adjacent sites in DNA with markedly different consequences.

Thryo-endocrine pathology, obstetric morbidity and schizophrenia: survey of a hundred families with a schizophrenic proband

This preliminary communication reports that the mothers of 104 schizophrenic patients had: (1) a significantly higher incidence of thyroid disease than a carefully matched control group; (2) significantly more abortions, still-births and greater infant mortality. The findings and possible relevance of thyroid disease to schizophrenia are discussed. Three prospective studies currently in progress are outlined.

Mixed-valence cytochrome oxidase-formate complex. A steady-state intermediate

At neutral pH, formate binds to the haem a3 component of cytochrome c oxidase to give a complex that reacts differently from the non-liganded enzyme with reducing agents. Addition of sodium dithionite to the formate complex leads directly to the formation of the fully reduced species, whereas reduction with ascorbate/tetramethylenephenylene-diamine can lead to the production of a mixed-valence species. The stability of this mixed-valence form was studied, and the species appears to represent a 'steady-state' situation that is stable only in the presence of an excess of O2 and reducing equivalents. Characterization of the mixed-valence complex by electron paramagnetic resonance and magnetic circular dichroism reveals the presence of reduced low-spin haem a together with reduced detectable copper and high-spin ferric haem a3.

Treatise on aeromedical evacuation: I. Administration and some medical considerations

Well conceived administrative procedures must be considered the backbone of a good, strong aeromedical evacuation system. These procedures must insure 1) centralized control of patient transportation by aircraft, 2) specialized medical attendants and equipment for inflight medical care, 3) facilities for limited medical care of patients entering, en route in, or leaving the system, and 4) communications with destination and enroute medical facilities concerning patient transportation. There are no absolute contraindications to aeromedical evacuation. However, patients with the following conditions require special consideration. Such conditions are 1) severe anemia, less than 2.5 million RBC/cc or less than 7.0 g hemoglobin/100 ml, 2) respiratory embarrassment, and 3) trapped gas within any of the body cavities. Medical problems in aeromedical evacuation defy resolution only when patient preparation has been improper. When the patient is properly evaluated, then unnecessary, costly, hazardous, and special flights are avoided. Aeromedical evacuation presents no problem so long as one remembers that man is adapted for life at or near sea level and that changes in pressure with increasing altitude affect his physiological processes. This invisible barrier will continue to challenge human ingenuity in the conquest of high altitude.

Treatise on aeromedical evacuation: II. Some surgical considerations

Preventive medicine is the primary responsibility of every physician. When prevention fails and therapeutic measures are required, the initial approach tends to be along a conservative line. When this approach fails, surgical intervention becomes a necessity. Surgical patients, both pre- and post-surgical, may be moved by aircraft providing that one is aware of the hazards in a hostile atmosphere in which pressure and temperature change with increasing altitude. Air or gas trapped in the body cavities expands in direct proportion to the decrease in pressure. This increased volume becomes significant at 5500 m, where the volume of air or gas in the body is doubled. Quite apart form intense discomfort and actual pain caused in certain types of injury, this expansion of gas at high altitude may constitue a real danger, such as in the probability of rupturing a recently sutured intestine and, in cases of pneumothorax, by disturbance of cardiopulmonary dynamics. Thus, aeromedical evacuation of the surgical patient becomes a challenge to those responsible for the medical care between the originating and destination hospitals.

Two years of routine patient movement in the U.S.A. (Jan. 1974-Dec. 1975)

During a 2-year period, Jan. 1974-Dec. 1975, a total of 102,547 routine patients were aeromedically evacuated from an originating medical facility to a destination hospital within the Continental United States (CONUS). It is the policy of the Department of Defense (DOD) that, in both peace and war, the movement of patients of the Armed Forces shall be accomplished by airlift when airlift is available and conditions are suitable for aeromedical evacuation, unless medically contraindicated. The DOD Regulation 4515.13-R states that a routine patient will be delivered to the destination hospital within 72 h after pickup from aerial ports or from the originating CONUS medical facility. During this 2-year period, 66% of all patients moved were delivered to their destination hospital the same-day they were picked up and 93% of all patients were delivered to their destination hospital within the 72-h DOD criteria for routine patients. In order to reach the destination medical facility, many patients had to remain overnight (RON) at an aeromedical staging facility (ASF). Contributing factors were weather, aircraft maintenance problems, expiration of the crew duty day, patients originating overseas, and patients moving out of originating areas and requiring a second mission to reach the destination hospital.

Recent trends in sex mortality differentials in the United States

Since 1920, American men, to an increasing degree, have experienced higher levels of mortality than American women for virtually all causes of death at almost every age. Recently, several authors have asserted that there is evidence of a change in these trends, caused primarily by rises in the levels of female mortality. Using age-adjusted death rates and data for the most recent years available (1960-1974). This paper shows that most female death rates are either stable or falling, and that the sex mortality differential for all causes except lung cancer is either stable or increasing.

Adaptation of rat pancreatic amylase and chymotrypsinogen to changes in diet

This study represents an attempt to determine the effect of dietary protein quality and hypophysectomy on the enzymic adaptability of the pancreas in the rat. The specific enzymes studied were amylase, which was purified by immunologic techniques and chymotrypsinogen (activated), which was isolated by affinity column chromatography. Content and synthesis of each enzyme were accurately determined in relation to total pancreatic protein. When rats were fed a 64% sucrose diet (19% casein), there was a two- to three-fold increase in synthesis of amylase. However, if a poor-quality protein (gelatin, gluten, or zein) was substituted for casein, there was no increase in the synthesis of amylase in response to increased carbohydrate. When rats were fed a 19% sucrose diet (64% casein), there was a significant increase in chymotrypsinogen synthesis. Of the poor-quality proteins, gluten was the only one effective in stimulating synthesis of chymotrypsinogen. Peptides, either free or as part of a protein, were necessary for the stimulation of chymotrypsinogen synthesis. Amylase synthesis in hypophysectomized rats was considerably depressed and unresponsibe to increased carbohydrate. This effect could be partially relieved with hydrocortisone, corticosterone, or thyroxin, but not with growth hormone. Hypophysectomy had little effect on synthesis or content of chymotropsinogen.

Physostigmine: effects on cognition and affect in normal subjects

Physostigmine was given intravenously to a total dose of 3 mg to 13 subjects; a placebo of 0.25 N saline was given intravenously to 10 other subjects; both groups received 1 mg of methscopolamine bromide subcutaneously preceding the intravenous infusions. A "physostigmine syndrome" consisting of decreased speech, slowed thoughts, mild sedation, expressionless faces, nausea, and decreased spontaneous activity was evident following doses of 1.5 to 2.0 mg of physostigmine. The capacity of short-term memory (STM) as measured by digit span tasks was significantly less for the subjects who received physostigmine than for the subjects who received placebo. No difference was observed between the two groups on tasks of consolidation from STM to long-term memory (LTM). Subjects who received physostigmine did not significantly differ from subjects who received placebo in their mood. However, two subjects in the physostigmine group, and no subjects in the saline group became tearful and depressed.

Group B streptococcal meningitis associated with otitis media

A full-term infant of an appropriate size for gestational age was found to have meningitis due to Lancefield group B beta-hemolytic streptococci at 8 weeks of age. On admission, the baby had bulging tympanic membranes Lancefield group B beta-hemolytic streptococci were isolated from aspirate of the middle ear, supporting the importance of otitis media in the pathogenesis of late-onset Lancefield group B beta-hemolytic streptococcal meningitis.

Congenital hypertrophic pyloric stenosis in Nigeria

Thirty one infants with congenital hypertrophic pyloric stenosis seen over a five year period (1970-1974) at the University College Hospital Ibadan are reported. Most of the patients presented late. There is a much higher male predominance but a lower prevalence among Nigerian first born infants when compared with Caucasian infants. It is suggested that the condition though uncommon is not rare in African infants, and that environmental rather than genetic or racial factors may be responsible for the apparent lower prevalence.

Five-year study of emergency aeromedical evacuation in the United States

During the time period, 1 July 1969-30 June 1974, a total of 7056 patients were moved on the C-9A Nightingale on an "urgent" or "priority" basis. In support of the request for urgent airlift, an average of 21 C-9A aircraft were launched monthly. The domestic aeromedical evacuation missions were highly flexible and productive, yet inexpensive when compared with other means of moving patients. A means for determining precedence for the pickup and movement of patients is essential for an aeromedical evacuation system. When the patient is properly evaluated and the urgency for flight movement determined, unnecessary, costly, hazardous, or special flights are avoided. More than 50% of the "urgent" patients airlifted during this 5-year span originated in the central part of the United States. The Northeast and Far West were each responsible for less than 10% of the patients requiring urgent evacuation over the same period. More than 50% of the urgent patients moved were in the categories of newborn complications, burns, and neurological problems. During this period, no patient was moved on an urgent basis for a psychiatric problem--aeromedical evacuation simply becomes a very effective tool in ensuring complete health care for seriously ill patients.

Folate supplements during pregnancy

In a controlled, prospective trial, the effects of giving ferrous sulphate 50 mg daily to 76 pregnant women was compared with giving ferrous sulphate 50 mg daily plus folic acid 0.5 mg daily to 82 women in 12 general practices in South-east England.No differences in obstetric complications were found between the two groups, although the evidence of some of the listed complications may be too rare for detection in a sample of patients of this size.

Non-steroid skin cream in traumatic dermatoses: A clinical open evaluation

Attention is drawn to the unwanted side effects of the long-term topical use of steroids on the skin. The topical use of steroids in conditions in which immunological factors are not involved is not necessary. An open clinical evaluation demonstrated that simple protective applications are quite effective in these conditions.

Effect of oral contraceptives and pyridoxine on the metabolism of vitamin B6 and on plasma tryptophan and alpha-amino nitrogen

The effect of supplementary pyridoxine on the metabolism of vitamin B6 as well as plasma tryptophan and alpha-amino nitrogen was determined in women using oral contraceptive agents. Ten women who were taking oral contraceptive agents and 11 who had never taken them served as subjects. Blood from the various biochemical measurements was drawn from fasting subjects before and after they had received an oral dose of 50 mg of pyridoxine-HCl daily fo 2 days. The use of oral contraceptive agents had no effect on the levels of blood vitamin B6, plasma pyridoxal phosphate, and plasma tryptophan. The activity of erythrocyte glutamic oxaloacetic transaminase was higher (P less than 0.05) in the oral contraceptive agent users than in the nonusers but the stimulation in vitro by pyridoxal phosphate was similar for the two groups. Plasma alpha-amino nitrogen was slightly lower in the oral contraceptive agent users than in the nonusers, but the difference was not statistically significant. The rise in blood vitamin B6 in response to pyridoxine was similar in the two groups, but the rise in plasma pyridoxal phosphate tended to be lower in the oral contraceptive agent treated subjects. Following pyridoxine supplementation, the basal activity of erythrocyte glutamic oxalocetic transaminase increased (P less than 0.01) in both groups of subjects and the stimulation in vitro by pyridoxal phosphate decreased correspondingly. Plasma tryptophan and alpha-amino nitrogen were unaffected by the supplementary pyridoxine.

In vivo study of a new radioisotope-powered cardiac pacer

A new radioisotopic pulse generator has been developed. It is 6 cm. long, 4.7 cm. high, 1.92 cm. wide, and weighs 61 Gm. (2 oz.). It is the smallest pulse generator made and has a life expectancy of over 20 years. The circuit is a conventional ventricular-inhibited (V.V.I.) type. In vitro testing has passed all Atomic Energy Commission requirements. The present study is concerned with in vivo testing of the complete pacemaker system, by means of both myocardial and endocranial electrodes, in 20 dogs with and without induced heart block. Extensive testing for electromagnetic compatability was carried out on 1 animal with induced heart block and a special, fast-rate pulse generator. Based on studies to date, the Atomic Energy Commission has issued a license for limited clinical trial which has already begun at the collaborating institutions.

The antiglobulin microcytotoxicity assay in HL-A genotyped families

HL-A genotyping was accomplished in 30 families (8 black, 21 white, and 1 American Indian) based on serological results obtained by our ususal lymphocytotoxicity assays. Each family was further tested by an antiglobulin microcytotoxicity method. Segregation patterns obtained by the latter method, compared with those of the former, showed few discrepancies. HL-A-identical siblings were serologically similar by the antiglobulin assay with frequency of discordant reactions at the same level as that of our regular two-stage lymphocytotoxicity assay. The antiglobulin method was shown to be highly reproducible with 1.3% discordance between duplicate tests. Many sera employed in routine cytotoxicity testing gave positive reactions with all family members in the antiglobulin assay (39% all positive by antiglobulin versus 16% by the regular cytotoxicity test), so that this method has limited usefulness for routine HL-A typing. The antiglobulin assay may have particular value, however, for identifying HL-A haplotypes in families, especially non-Caucasian, which give infrequent positive reactions in the usual lymphocytotoxicity assays.

Micropuncture and microanalytic studies of the rat testis and epididymis

Micropuncture techniques developed for the study of renal physiology have been adapted for investigation of the male reproductive tract. Ultramicro specimens were obtained in vivo from the tubules of the rat testis and epididymis. These samples were analyzed for sperm morphology and concentration. The new methods developed to conduct these studies are discussed in detail. The mean in vivo spermatocrits were 0.411 plus and minus 0.029, 0.355 plus and minus 0.019, and 0;731 plus and minus 0.028 in the seminiferous tubule, caput epididymidis, and caudal spermatocrit was significantly higher than the spermatocrit in the caput or seminiferous tubule. The percentages of abnormal spermatozoa in the caput and cauda were 5.5% plus and minus .7% and 4.3% plus and minus .6%, respectively.

Micropuncture and microanalytic studies of the effect of vasectomy on the rat testis and epididymis

Micropuncture techniques adapted for in vivo use in the male reproductive tract were used to study the effect of vasectomy on the concentration and morphology of spermatozoa in the seminiferous tubules and ductus epididymidis of the rat. Regardless of surgical technique, 85% of all rats which had previously under vasectomy developed a speratic granuloma at the proximal end of the ligated vas deferens. Vasectomy did not affect the weights of the ipsilateral (vasectomized) testes. Vasectomy without granuloma formation resulted in an elevation in the weight of the ipsilateral epididymis and an increase in the concentration of spermatozoa in the ipsilateral cauda. Vasectomy complicated by granuloma formation caused a significant increase in the ratio of the spermatocrit in the seminiferous tubule to that in the caput. In the vasectomized rat without granuloma, significantly more abnormal spermatozoa were in the caput than in the cauda; in the normal rat, the concentrations of abnormal spermatozoa in the two regions were not significantly different. Vasectomies with and without granuloma formation are distinct phenomena and should be investigated separately.

Variability in judgments of articulation when observer listens repeatedly to the same phone

This study pertains to variability in articulation judgments made by Os who listened to repetitions of the same stimulus. In the first portion of the study, four Os were asked to listen to six tapes, each of which was prepared to present 90 repetitions of a syllable. The syllables were /sa/ and /rk/.2 The /s/ and /r/2 in two of the syllables were correctly articulated, in two they were moderately distorted, and in two they were severely distorted. Correctness of articulation of the target phones had been established previously by a panel of judges using a scaling procedure. The speakers were children with articulation problems. A total of 24 sets of judgments were obtained. For three of those sets, O frequently shifted between assessment of the phone as correct and incorrect. In the second portion, each of three tapes was evaluated by five of 15 judges. Two tapes were reused from the first part of the study, and a new tape presenting the same production of /is/ 90 times was also used. No judge listened to more than one tape. Again, a record was made of the frequency with which judges shifted in their assessment of a given articulation as correct or incorrect. More judges reported 12 or more shifts in the second portion of the study than in the first. O's consistency should be investigated in the situation where O evaluates a series of similar misarticulations of phones from the same phoneme.