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WHEN a squirrel-cage motor is switched in any way, whether while running or at rest, transient torques, which are usually several times the steady-state torque, occur and must be considered in design. It was desired to obtain a general semi-quantitative view of these torques by considering a limiting case which is accessible analytically with the expectation that a simple rule would be apparent for estimating the magnitude of these torques from design data. No such rule was found, and we must be content to exhibit limiting transient torque curves for certain types of motors in the commercial range and to provide accurate formulas for calculating such limiting torques for types not considered here. The limiting case studied involves the following assumptions

Summary Electrical anesthesia was induced in 75 mongrel dogs using direct current combined with an alternating rectangular wave applied in the midsagittal plane between the chin and the posterior parietal area with platinum-sponge electrodes. Duration of the wave was varied from 0.1 to 1. millisecond: the frequency from 100 to 1000 cps. The electrodes were applied by a simple technique of gluing with Eastman 910 adhesive and tape. Systolic and diastolic blood pressure increased during induction and with any subsequent increases in current or with any sudden decrease in current. Gradual decreases in current did not have this effect. Bradycardia (sometimes alternating with tachycardia) occurred at the same time as the hypertension. During steady states of anesthesia, arterial blood pressure and rhythm returned to normal. the blood pressure more slowly. Upon cessation of current, blood pressure (if still elevated) immediately returned to normal. Prior sedation reduced these pressor reactions. Electric current applied to an extremity resulted in similar cardiovascular changes, which were ablated by denervation of the extremity. Placing of electrodes on the cranial bones did not decrease cardiovascular changes, nor did prefrontal lobotomy. All combinations of durations and frequencies produced hypertension and bradycardia. These changes were greater with lower frequencies and shorter durations. However, less satisfactory anesthesia resulted with the higher frequencies. Gradual or abrupt application of an anesthetic level had similar cardiovascular effects. An instantaneous application of an anesthetic level using 100 cps with a 1 millisecond pulse was adopted for routine use. A table of peak voltages was obtained with various combinations of wave frequency and duration. The peak voltage increased with decreasing percentage of time of passage of current (pulse duration/period ratio). It is suggested that this may be the dosage measurement related to anesthetic level. Respiratory and pressor reactions to intravenous sodium cyanide and to inhaled carbon dioxide were present during and after electrical anesthesia. The occasional increases in body temperature which occur during electrical anesthesia appear to be the result of muscular activity combined with failure of the panting mechanism and can be avoided by paralyzing drugs or adequate pulmonary ventilation. Skin (paw) temperature reactions to electrical anesthesia were not consistent. Skin temperature increases were observed after barbiturates (prolonged increase) and succinylcholine (brief increase). Electrical anesthesia would appear to be a suitable method for the surgical preparation of experimental animals for awake experiments.

The filling pressure in the minute vessels of the skin of the foot has been estimated by a method of elevation and reactive hyperemia. A series of 90 observations was made on 78 patients. This test has been found helpful in evaluating the degree of arterial insufficiency, permitting a more accurate selection of patients to be treated by conservative methods, local amputation or more radical procedures.

Lack of consistent deep venous filling has been a shortcoming in phlebography of the lower extremity. Certain measures commonly adopted to improve phlebographic examination have included tourniquet placement about the ankle, internal rotation of the leg, serial filming, and biplane examination. The use of higher doses of contrast medium has been helpful only when the examination is performed in the erect position (3). Performance of the examination in the erect position is the only maneuver which has reportedly resulted in consistently good visualization of the deep venous system (4). This was pioneered by Lindblom (5), who felt that the poor visualization of the deep veins in the horizontal position was due to sedimentation of the contrast medium since it is heavier than blood. Greitz (3) showed that the effect was due to a lack of mixing rather than sedimentation and found that a position 65° from the horizontal was as successful as the vertical. Phlebography in the erect or semierect position is not wi...

The nutrient arteries of eleven tibiae and eight humeri were ligated. In every instance there was an immediate and usually a large decrease in intramedullary pressure. In nine bones the pressure rose to preocclusion levels within less than three hours. In an additional eight the pressure returned to normal within from four to twenty-two days. In only two instances did the postligation pressure not recover during the period of observation (sixteen to twenty-five days). Post mortem injection of the subclavian or femoral artery resulted in filling of the nutrient arterial system via collateral channels in all specimens.

Osteomalacia is a metabolic disease of bone in which there is a deficient mineralization of the bony matrix. The amount of matrix present is normal or slightly increased. The defective deposition of calcium salts is due to the lowered concentration of calcium or phosphorus, or both, in the body fluids, as a result either of impaired absorption from the gastrointestinal tract or increased renal excretion. Because of their decreased mineral content, the bones are weakened, becoming soft and bending readily. Deformities of the extremities, pelvis, vertebrae, and skull may occur. As a result of the weakening of the bones, the osteoblasts are stimulated to lay down new bone matrix and elaborate alkaline phosphatase, which is usually present in abnormal concentration in the blood serum (1). In some cases of osteomalacia, multiple, almost symmetrical, radiolucent bands of diminished density, resembling fractures, occur in the cortex of the bone. These pseudofractures are seen most frequently in the axillary bord...

Effects of crude oil and salinity stress on the metabolism of two common filter feeding animals (Mytilus edulis and Modiolus demissus) have been investigated. Carbon budgets have been calculated for each species under a variety of combination of oil content and salinity. Both reduced salinity and crude oil tend to decrease the net carbon balance for each species; stresses from each source were additive in their effects on experimental animals. Although similar responses to oil were shown by each species, Mytilus appeared to be somewhat more resistant to oil than Modiolus.

Difficulties were encountered with reciprocating pumps for the continuous circulation of mercury. An all‐metal pump, without moving parts, operating on the principle of a polyphase induction motor was developed. The mercury flows in the annular region between two concentric tubes. Surrounding the tubes are coils connected to a polyphase supply. The result is a series of magnetic ripples traveling along the axis of the tubes which drag the mercury along by virtue of the currents induced in it. Lifts in excess of a meter and capacities in excess of 50 cc per second have been obtained.

S MALL BOWEL reversal was first studied by Mall [1}, Miihsam [2] and McClure [3]. The conclusion of these early investigators was that small intestine reversal was fatal to dogs. Within the last ten years interest has been reawakened in surgical procedures designed to delay intestinal transit time [4,5]. Reversal of a small se~nent of terminal ilcmn by these recent investigators has demonstrated that this procedure is compatible with prolonged survival. Protracted survival with maintenance of nutritional balance after massive small bowel resection and end to end anastomosis is frequently difficult or impossible to achieve [6]. The exact length of small bowel necessary to preserve adequate nutrition is variable and depends on several factors, i.e., adequacy of the blood supply, whether the residual segqnent is proxinml jejunum or terminal ileum, the activity and age of the individttal and even perhaps the efficiency of his metabolic processes. Infarction of small bowel may be due to underlying cardiovascular disease, producing thrombosis or embolism in tim superior mesenteric artery (or one of its main branches), intestinal atresia, cardiac decompensation, injury, volvulus, internal herniation or strangulation obstruction clue to adhesions or tmnors. The literature on the subject of small bowel resection, as well as our own experience with $5 per cent small bowel resection in eighty. three mongrel dogs in the experimental surgery laboratories of Presbyterian Medical Center and Children's Hospital, San Francisco, indicate the creation of the following metabolic abnormalities: (1) hypowflemia, (2) metabolic acidosis, (3) megaloblastic anemia, (4) markedly reduced absorption of vitamin Br.,, fats and fat ty acids (Pz~-tagged oleie acid, Dxylose cholesterol) [7]. A considerable portion of neutral fat is absorbed undigested and this process is largely localized in the proximal small bowel. When this area is removed, absorption is slower, but eventually takes place from lower se~nents after enzymatic digestion. The jejunum absorbs all of the carbohydrate and most of the fat and protein before these substances reach the ilemn. Upon resection of the ileum and ile~ecal valve, absorption by the jejunmn is greatly decreased due to "jejunal hurry," i.e., decreased intestinal transit time because of loss of the ileocecal valve. (5) Hypoproteinemia with relative increase in globulins and decrease in albumin. This situation frequently will cause partial anastomotic obstruction and compound the state of malnutrition [8,9]. (6) Hypocalcemia.

Observations on a 910 km pulsed ionospheric forward scatter circuit suggest that a complex set of events occurred that gave rise to enhanced ionisation with a high degree of irregularity in the scattering region. Both prompt and delayed effects were observed and these are discussed in detail.

The thoracic duct is generally accepted as the major pathway of lymphocytes enroute to the circulating blood (1, 2, 3), accounting for approximately 70 per cent of all the lymphocytes in the peripheral blood. The remainder of the lymphocytes are said to enter the blood directly via the lymph from other sites (2). Reliable information concerning the hematologic content of lymph in the thoracic duct of man has been fragmentary and limited to chance observations in few patients (4). The thoracic duct lymph is reported to flow from one to six hours after death (5, 6). Consequently, an attempt was made to study the cellular components of human lymph obtained by cannulation of the thoracic duct within one hour after death and then in vivo if a feasible technic could be developed (7). Volumetric measurements of the flow of lymph in addition would permit an estimation of the number of cells delivered per unit time into the peripheral circulation via the thoracic duct (8). Since at least two thoracic ducts are present in man in addition to innumerable other lymph-to-blood connections, it was realized that these anatomical considerations seriously limited the interpretation of single samples. Consequently cannulation of the major thoracic duct for continuous drainage over prolonged periods was undertaken.

In the literature the nutrient artery to the diaphysis of the canine femur has been described as arising from the medial circumflex femoral artery which is a branch of the deep femoral artery. However in 19% to 100 canine hind extremities dissected after injection with colored media, the femoral nutrient artery arose from a large muscular branch (the proximal posterior femoral) of the superficial femoral artery. In 17% of 42 dogs one femur only was supplied by this variant. In three additional femurs other variations occurred.

A method of obviating the carotid and aortic body chemoreceptor response has been presented consisting of excision of the carotid bodies and denervation of the aortic body or bodies. The physiological responses of these animals to high altitude acclimatization are characterized by a marked increase in erythrocyte volume, a decrease in plasma volume, and a minimal increase in total blood volume. The respiratory response to anoxia is markedly decreased and the sensitivity to inspired CO 2 at high altitude is unchanged from that at sea level.

As part of an ongoing study of the long-term effects of the Zoe Colocotroni oil spill of March 17, 1973, in Bahia Sucia, Puerto Rico, the effects of the remaining oil on the red mangrove trees in the impact area were investigated. This study involved four sampling trips to the spill site and a reference area outside the spill zone between April 1979 and April 1981. The present study was based on the observation that stressed mangrove trees in the heavily oil-affected areas had a similar appearance to trees exhibiting stress due to hypersalinity in unoiled areas. The working hypothesis was that petroleum hydrocarbons induce stress in salt-excluding plants such as red mangroves by disrupting the ability of the roots to exclude ions from seawater. Measurements of sodium (the principal seawater cation) and potassium (a major physiological ion) were made on leaf samples taken from trees from oil-affected areas and reference areas. Sediment core samples were taken from the root zone of the trees sampled at each site and analyzed for hydrocarbons by gravimetric and gas chromatographic methods. The results show a relationship between sediment hydrocarbon concentration and the ratio of sodium to potassium for mangrove leaves sampled at each site. The results show that for trees exposed at the root zone to the least weathered oil, the values of this ratio for the leaves had the largest values, reflecting an oil-induced impairment of the salt (Na) exclusion mechanism. This approach to measuring the physiological health of mangrove trees at an oil spill site offers a potentially useful means of documenting oil stress and recovery from oil stress in salt-excluding halophytes. Because oil stress in mangroves appears to be a root membrane-directed effect, there may be a “window in time” between initial oil impact and plant damage, as oil penetrates the sediments, during which mitigation measures could be taken.

SummaryIt has been proposed that delaying ‘pushing’ in the second stage in labours associated with epidural analgesia will reduce the incidence of instrumental delivery. Two similar groups of 100 primigravid women in labour conducted under epidural analgesia were compared. The first group commenced ‘pushing’ as soon as the second stage was diagnosed, whilst the second group was asked to wait at least one hour before commencing to ‘push’. Sixty-three in the second group were able to comply. The incidence of forceps delivery was not reduced in the group that had been asked to wait, in fact it was higher. Delaying ‘pushing’ in the second stage in labour associated with epidural analgesia is difficult to apply uniformly and is of no practical benefit.

A vascular surgical clamp is described which has a single row of needlepoint teeth for the jaws. In our experience, the use of fine round and pointed teeth seems to afford less trauma and greater control of the vessel.

Salt marshes and mangrove areas are very important in shoreline development and protection (1,2,3). These same areas are highly productive (4,5,6) and are important exporters of detritus to nearby communities (7,8). Both salt marshes and mangrove forests are important to fisheries production beyond their role as exporters of detritus (8,9).

A series of experimental studies was carried out as part of the Baffin Island Oil Spill (BIOS) Project to define the behavioural, physiological and biochemical reactions of three arctic marine benthic invertebrate species exposed to chemically dispersed crude oil. Behavioural responses and patterns of hydrocarbon accumulation and release observed in the bivalves and the urchin during the 1981 field spill were similar to those observed during the laboratory simulations. Ostial closure, loss of responsiveness to mechanical stimuli and narcosis were characteristic of the bivalves. Exposed urchins displayed a functional loss of tube foot and spine behaviour. Detailed hydrocarbon analysis indicated different uptake dynamics among the species. The effects of dispersed oil were immediate and short lived and resulted in temporary accumulation of hydrocarbons. Depuration of these stored hydrocarbons occurred during the experimental recovery period. In vivo biodegradation of hydrocarbons was indicated in the bivalves. Physiological parameters measured in bivalves exposed to oil included elements of scope for growth, activity of aspartate aminotransferase and glucose-6-phosphate dehydrogenase. Dose-response relationships between physiological rates and hydrocarbon body burden were apparent. Key words: petroleum effects, Arctic, invertebrates, metabolism, enzymes, behaviour, biodegradation, hydrocarbon uptake, Baffin Island oil spill, dispersant

Metabolic processes in eastern arctic copepods Calanus hyperboreus were analyzed during the post-bloom period (August-September). Mixed adult and subadult copepods were collected from 12 stations in Baffin Bay (Davis Strait to Lancaster Sound) by trawling from 0-300 m. Measurements were made of clearance rate, O2-consumption and NH3 excretion. The cruise track included 6 stations in oil-seep contaminated waters of Scott Inlet and Buchan Gulf. Physiological parameters for populations of C. hyperboreus from the latter stations were compared with those from non-seep stations. Mean O2 consumption rates (0.309 - 0.907 µl O2 / mg dry wt / h) for all stations were similar to those described for Antarctic calanoid species but were higher than reported for more northern arctic waters. Mean ammonia excretion rates (0.023 - 0.071 µg N / mg dry wt / h) were somewhat lower than reported for comparable Antarctic species and were similar to values from other eastern arctic studies. O:N ratios for 11 of the 12 stations occupied ranged between 8.4 and 22.1, indicative of protein-based metabolism. The single exception was a High Arctic station with O:N ratio 43.6. Clearance rates were low to nonexistant for all stations. Most of the non-feeding values came from the Scott Inlet-Buchan Gulf region of western Baffin Bay. At those stations in this region a strong negative correlation (P

The results of the Elevation Reactive Hyperemia Test (ERHT) and the transcutaneous Doppler ultrasound ankle blood pressure (DAP) have been compared in a series of 115 cases with ischemic lesions of the foot. The ERHT was carried out by simple elevation of the foot or elevation with the circulation temporarily obstructed by a blood pressure cuff following which the foot was gradually lowered until the reactive hyperemia was seen in the skin and the height above the right atrium was estimated. The appearance of the hyperemia at 35 cm above the right atrium will allow healing of local ischemic lesions and at the height of 45 cm or above indicates a zone at which amputation may be carried out successfully. In the same series the DAP using 60 mmHg as the cut off point showed 40% healing with a pressure less than this level and 40% failed with a pressure above this level. The DAP gave no consistent prediction of the healing of ischemic lesions or of amputations.

After oil spills, various species of filter-feeding bivalve molluscs have been shown t o absorb petroleum hydrocarbons from the water column and suspended particulate matter. There have been numerous published studies in which hydrocarbon concentrations in oil exposed bivalves have been measured both in the field and in the laboratory(for reviews see 1,2,3). Given the commercial value of such species as clams, oysters, and mussels, it is important to understand the kinetics of oil depuration from bivalve tissues with the goal of possible salvage of impacted animals and to understand the basic physiological processes involved.

To examine the influences responsible for shaping the T-cell repertoire in vivo, we have introduced T-cell receptors of defined specificity into mice. In this report, we analyze transgenic mice carrying a T-cell receptor alpha-chain gene from a pigeon cytochrome c-reactive T-cell line. A variant of this construct, which has the immunoglobulin heavy-chain enhancer inserted into the JC intron, was also introduced into mice. Addition of the enhancer increased the steady-state level of transgene-encoded mRNA three- to fivefold in cultured T cells, leading to a two- to threefold increase in surface expression. In vivo, the difference between these two constructs was even more significant, increasing the number of transgene-positive cells from approximately 5 to 70% and the T-cell receptor surface density two- to threefold. Surprisingly, while surface expression of either type of transgene was limited to T cells, we found little tissue specificity with respect to transcription. In T cells expressing the alpha chain from the enhancer-containing construct, immunoprecipitation with a 2B4 alpha-specific monoclonal antibody revealed the expected disulfide-linked dimer. Costaining of these T cells with the 2B4 alpha-specific monoclonal antibody versus anti-CD3 indicated that expression of the transgene-encoded alpha chain precludes expression of endogenous alpha chains on the majority of cells; in contrast, 2B4 alpha-chain expression from the construct lacking the enhancer is inefficient at suppressing endogenous alpha-chain expression. In mice of the enhancer lineage, Southern blot analysis indicated suppression of endogenous alpha-chain rearrangements in T-cell populations, consistent with the observed allelic exclusion at the cellular level. Interestingly, newborn, but not adult, mice of this lineage also showed an increase in retention of unrearranged delta-chain loci in thymocyte DNA, presumably resulting from the suppression of alpha-chain rearrangements. This observation indicates that at least a fraction of alpha:beta-positive T cells have never attempted to produce functional delta rearrangements, thus suggesting that alpha:beta and gamma:delta T cells may be derived from different T-cell compartments (at least during the early phases of T-cell differentiation).

Spontaneous vasomotor activity, as evidenced by the presence of alpha or beta waves in the paw plethysmogram, was demonstrated in 10 sympathectomized, 4 denervated, and 8 (ganglionic or adrenergic) blockaded extremities in dogs. Alpha waves occur during natural sleep and during anesthesia. They are present after removal and denervation of the carotid and aortic chemoreceptors. They occur in the splenectoinized animal. Alpha waves are usually synchronous in a pair of normally innerverted extremities. They may be synchronous, asynchronous, or absent in one paw when one extremity (or both) is denervated or sympathectomized. The significance of this information is discussed in relation to the factors which may control spontaneous vasomotor activity.

Blood flows in the external iliac artery measured with noncannulating square wave electromagnetic flow probes are reported in 15 unmedicated rhesus monkeys. Blood flows up to 22 months after unilateral lumbar sympathectomy increased 5–200% when compared to simultaneous contralateral flows or ipsilateral flows prior to sympathectomy. Central (aortic) blood pressures in 13 old monkeys were 80–130 mm. Hg diastolic and 105–185 mm. Hg systolic. Cardiac output in two monkeys was 80–200 ml./kg./minute.