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Obesity affects approximately one-third of the population of the United States. Pulmonary complications are common following upper abdominal surgery, and constitute the most frequent postoperative complication in the obese surgical patient. This literature review addresses the pathophysiology of the pulmonary changes associated with simple obesity and examines intraoperative and postoperative changes which occur in this patient group. Measures used prophylaxis and management of these complications are reviewed.

Polyurethane vascular prostheses offer the potential of superior thromboresistance and reduced anastomotic hyperplasia compared to existing Dacron and ePTFE alternatives, but have suffered from susceptibility to biodegradation, with resulting mechanical failure. To address this problem, the authors have developed and evaluated a composite prosthesis comprised of: 1) an inner blood interfacing elastomeric porous membrane made from Corethane, a proprietary Shore 80A polyurethane like material substantially devoid of ether/ester linkages, with superior biostability over conventional polyether urethanes, spun into a nonwoven structure with fiber diameters 10-15 microns and pore sizes 30-60 microns filled with gelatin +/- heparin; and 2) an outer soft, tissue interfacing, warp knitted Dacron mesh bonded to the inner layer to assure long-term dimensional stability. Twenty 4 mm ID x 5 cm L composite prostheses, half with heparinized gelatin (the remainder nonheparinized) were implanted as femoral interposition grafts in 10 dogs. Four of the 10 nonheparinized grafts occluded. All 10 with heparin remained widely patent, with two explanted at 6 months showing vascularized connective tissue growth through the graft, in contrast to the giant cell inflammatory response to the Dacron mesh, with a substantially endothelialized neointima and no Corethane biodegradation. Of the 10 patent grafts at 1 year follow-up, none showed aneurysm formation. This vascular prosthesis provides compliance superior to ePTFE and Dacron alternatives, with excellent suture retention and good kink resistance, while combining the superior thromboresistance and tissue ingrowth properties of polyurethanes with the proven biostability of Dacron.

Eighty-one patients with primary Roux-en-Y gastric bypass for obesity underwent revisional surgery for staple line failure. All patients (100%) were included in the follow-up. Two years later, patients had an excess weight loss of 77%; 91% of the patients had a final weight loss of 50% or more of their excess weight. Weight loss of revision patients was comparable to that reported for patients with primary operations. It was concluded that revision for staple line failure is clearly justified.

Several previous investigators have reported an incidence of folic acid deficiency following gastric bypass surgery of up to 38%. Failure to encounter any folic acid deficiencies in our postoperative patients led us to discontinue follow-up folate studies for several years. However, due to repeated references to this deficiency in the literature, we re-instituted folate studies as part of the routine follow-up of our patients. Preoperative serum folate levels were obtained in 1,067 patients and preexisting deficiencies found in 63, an incidence of 6%. Of the 588 folate levels determined 1 to 10 years following gastric bypass, only six were less than 3.0 ng/di, an incidence of 1%. All patients were instructed preoperatively and postoperatively to take multivitamin/mineral supplements after gastric restrictive surgery, and were continually educated on their importance. In a bariatric surgery practice in which patients are instructed, reminded, encouraged and even badgered into taking postoperative vitamin/mineral supplements, folate deficiency should be a rarity. In such circumstances, folate deficiency may well act as a sensitive marker of non-compliance.

A 32–33 bp highly repeated DNA sequence, TkS1, has been isolated from genomic DNA of the newt Triturus karelini digested with the restriction endonucleases HaeIII or AluI. TkS1 is known to be localised in the centromeric heterochromatin of all the chromosomes in T. karelini and the related species T. cristatus TkS1 has been shown to be present in varying amounts in the genomic DNA of a range of species of Triturus, including representatives of the two main subgenera Triturus and Palaeotriton. A programme of sequencing of monomers, dimers and trimers of TkS1 was carried out in order to determine the level of conservation of the sequence within and between species of Triturus. Altogether 204 monomer (32/33 bp) clones were made of TkS1 from three individuals of T. karelini, and one individual each of T. cristatus, T. carnifex, T. dobrogicus and T. marmoratus, all members of the subgenus Triturus and the cristatus species group. A number of dimer (64 bp) and trimer (96 bp) clones were also made from DNA of a single specimen of T. karelini digested with HaeIII or AluI. Three distinct types of TkS1 were identified in all species examined, except for T. marmoratus where only two of the types were found. The types were distinguished on the basis of certain recurring divergent patterns in monomers sequenced from T. karelini. Type 1 is mainly characterised by the presence of an AluI site at positions 24–27 and type 3 mainly by the presence of an additional base (C) at position 14. Type 2 normally lacks the AluI site and the C at position 14, as well as having a number of other distinguishing features. TkS1 and its three types have remained remarkably constant in sequence since before the divergence of T. marmoratus from other species in the cristatus species group, about 10 million years ago. Examination of all 204 monomer clones and comparison with consensus sequences for the three types shows less than 5% divergence at any one position in the sequence. There is good evidence from examination of dimer and trimer clones of TkS1 that the different types are intermingled with each other, and all three types are likely to be present on all chromosomes. Dimeric (64 bp) TkS1 clones constructed from AluI fragments of T. karelini DNA show evidence of a trimeric (96 bp) “supertype” with the pattern type 1-type 3-type 1 that is much more common than would be expected on a random basis. The properties of TkS1 are discussed in relation to models for the involvement of highly repeated satellite DNA in chromosomal growth and evolution.

To test the general applicability of the hypothesis that diabetes mellitus causes increased polyol pathway activity, decreased tissue free myo-inositol, and resultant pathological changes in tissues susceptible to the ravages of diabetes, we measured glucose, sorbitol, and myo-inositol with quantitative histochemical techniques in layers of the cornea, the aortic myointima, the cardiac left ventricle and atrioventricular node (AVN), and retina and kidney after 19 days or 2 mo (mildly diabetic non-insulin-treated [MD] and severely diabetic insulin-treated [SD] groups) in the alloxan-induced diabetes model. In the aqueous humor, glucose rose linearly with increased serum glucose, sorbitol was markedly increased in the MD and SD groups, and myo-inositol did not change in any diabetic group. There was no change in glucose or sorbitol in aortic myointima in any group, but myo-inositol was decreased in 19-day diabetic rabbits by 26%, unchanged in MD rabbits but paradoxically increased by 60% in SD rabbits. Glucose, sorbitol, and myo-inositol increased in all three corneal layers in SD rabbits but only in epithelium and stroma in 19-day and MD rabbits. AVN glucose and sorbitol did not change in 19-day diabetic, MD, or SD diabetic rabbits. AVN myo-inositol was three times higher than ventricular myo-inositol and did not appear to change in SD rabbits. Retinal pigmented epithelium myo-inositol was decreased 30% in SD rabbits. Glomerular myo-inositol was also decreased, but not significantly, in SD rabbits. We conclude that the paradoxical increase in corneal and aortal myo-inositol raises fundamental questions about the general applicability of the myo-inositol-depletion hypothesis.

The dynamics of platelet deposition and embolization from control and heparin bonded polyurethane catheters (CPC and HBPC) was evaluated with In-111 labeled autologous platelets (IN-PLT) and a computerized gamma camera (CGC). Ten non-heparinized dogs (18-25 kg) were catheterized in both femoral arteries with 10 cm of CPC and HBPC (5 Fr., Cordis) 24 hr after injection of 300-420 microCi of In-PLT, and imaged for 3 hr with the computerized gamma camera. The regional platelet deposition curves (RPDC) indicated multiple peaks and valleys; the curves were analyzed for early rate of thrombus formation (upswing), thrombus retention time (full width at half maxima of the RPDC-peak), and rate of embolization (downswing) on both catheters. The four parameters (mean +/- SD) of thrombosis on catheters and integral of the radioactivity time curve for the 3 hr duration of imaging were calculated from normalized counts/sec. The rate of thrombus formation and rate of embolization are higher for the control than HBPC, suggesting that heparin-bonding decreases the early rate of thrombosis and embolization. The thrombus adhesivity and retention time appear shorter for the control catheter, indicating that the control thrombogenic catheter forms multiple thrombi and emboli than HBPC. The integral appears larger for the control catheter than HBPC. In vivo (dynamic) studies, in vitro studies, and critical analyses of the radioactivity time curve were essential for complete evaluation of thrombogenicity of catheters and other cardiovascular prostheses.

The dynamics of platelet deposition on CPC and HBPC was evaluated with In-111 labeled platelets (In-PLT) with a computerized gamma camera (CGC). Ten non-heparinized dogs (18-25 kg) were catheterized in both femoral arteries with 10 cm of CPC and HBPC (5 Fr., Cordis, Inc.) 24 hours post-injection of 300-420 microcuries of In-PLT, and imaged for 3 hours with gamma camera. The regional platelet deposition on three segments of catheters and puncture site was determined. The catheters were harvested and radioactivity on the catheter segments (proximal: PROX, middle: MID, distal: DIST and puncture site: PS) of both was determined. From the platelet count in blood, radioactivity in blood and segments of catheters, adjacent artery and area of artery and catheter, the platelet-density [X10(3)] (mean +/- S.D.) on catheter and artery were calculated and tabulated: (table; see text) The large standard deviation of retained platelets is due to embolization. The platelet-density and regional counts on catheter segments were lower in the HBPC than CPC. The rate of platelet-deposition was lower in the HBPC than CPC. Most of the thrombi were lost during pullout of the catheter. Both in vivo (dynamic) and in vitro studies were necessary for evaluation of CPC thrombogenicity.

This is a brief evaluation of web sites available on the Internet. Particular emphasis has been placed on those which provide information concerning the indications, benefits, risks and outcome of surgery for obesity. These web sites are suitable for use as informational sources for potential candidates for surgery for obesity.

In deciding whether or not to make condoms available in their schools the North Okanagan-Shuswap School District in British Columbia analyzed data to determine whether the availability of condoms in public schools affect the pregnancy rate among girls aged 10-14 and 15-17. Overall data showed that the larger districts had a greater decrease than the smaller more rural districts but the change was negligible in both cases. In this review several complicating factors that remained unchecked are identified. These include the following: location lifestyle population mix in some districts socioeconomic factors influence on educational and health issues and the time when the condoms were introduced. Thus it is indicated that condom availability has no net effect on school-aged pregnancy problems. This review shows that pregnancy rates are extremely variable and will not be reduced by simplistic solutions. With such variability of pregnancy rates rates must be examined over a long term. Moreover reducing pregnancy rates requires working with young people since they are the ones affected by the problem.

Objective: To evaluate long-term outcome of gastric restrictive surgery in morbidly obese patients aged 55 years and older. Design: Retrospective review with 3- to 13-year postoperative follow-up. Average follow-up 6 years. Setting: Private surgical practice with bariatric surgery specialty. Study Participants: Eighty-eight morbidly obese patients, 73 women and 15 men, aged 55 years and older. Intervention: Between 1977 and 1989, 77 patients had Roux-en-Y gastric bypass, four had vertical banded gastroplasty, and seven had silicone ring vertical gastroplasty. Main Outcome Measures: Weight loss, change in incidence of comorbidity, and reduction in medication use. Results: Patients had an average of 57% excess body weight loss, lost 31 kg, and decreased their body mass index by 12 kg/m 2 . There was a 20% to 48% reduction in the number of patients requiring medication for obesityrelated disorders (eg, diabetes mellitus and hypertension). Body mass index of less than 30 kg/m 2 was achieved and maintained by 42% of patients. Conclusion: This form of therapy is appropriate for selected patients in the older age groups. ( Arch Surg . 1993;128:1153-1157)

The safe period of anoxic arrest of the heart is related to its individual metabolic activity rather than to a specific time interval. The capacity of the heart to produce energy through anaerobic metabolism, on which survival depends, has been assessed in this study by continuous monitoring of intramyocardial carbon dioxide tension (Pco2). Two groups of 12 dogs each were placed on total cardiopulmonary bypass at 38° C. and 28° C., respectively. Anoxic arrest of the heart was produced by cross-clamping of the ascending aorta and venting of the left ventricle. Intramyocardial Pco2 was measured by a mass spectrometer, and carbon dioxide accumulation curves were plotted. An initial period during which the Pco2 increased in a linear fashion was followed by a period during which the rate of rise gradually decreased until a plateau was reached. If the arrest was terminated at the transition point between these two periods, all hearts could be resuscitated. If the arrest was terminated when the carbon dioxide accumulation curve had reached a plateau, none of the hearts could be resuscitated. These results are given in the text. Our technique defines a point at which anoxic arrest can be safely terminated. This point can be significantly extended by reducing the metabolic activity of the heart by moderate hypothermia.

Twenty-four rectangular metal plates were fabricated with surface regions in three different pore size ranges (5-20 microns, 20-50 microns, 50-200 microns). The plates were implanted into the dorsal subcutaneous tissue of 12 adult mongrel dogs for periods of 4, 8, 12, and 16 weeks. After animal sacrifice, the fibrous tissue which adhered to the porous-surfaced regions of each plate was mechanically peeled off to give an indication of the strength of tissue attachment. The tissue was examined by both transmitted light and scanning electron microscopy. At each time period, the tissue that contacted the porous regions was found to be collagenized fibroconnective tissue. The mechanical tests indicated an increasing strength of tissue attachment with increasing implantation time and pore size range. The largest pore size range of approximately 50-200 microns produced a mean peel strength of attachment of 27.5 g/mm at the 16-week period.

The symposium of which this book is a record was first suggested in the autumn of 1982. At that time, all members of the BSDB committee were persons who were primarily concerned with studies of animal development, and the initial tendency was to think along these lines.

Multidose administration of cardioplegic solution during cardiac operation is intended to maintain both electromechanical arrest of the heart and myocardial hypothermia as well as to remove accumulated metabolites of anaerobic glycolysis. This study was conducted to assess the effect of multidose infusion of three different types of cardioplegic solution on tissue acidosis during global myocardial ischemia. Three groups of five dogs each were placed on cardiopulmonary bypass and the aorta was cross-clamped for 3 hours. The hearts were maintained at a constant temperature (20° C) and cardioplegic solution was infused at an initial dose of 500 ml and five supplementary doses of 250 ml administered every 30 minutes. Group 1 received a crystalloid solution weakly buffered with sodium bicarbonate, Group 2 received a blood-based solution, and Group 3 received a crystalloid solution strongly buffered with histidine (Bretschneider's solution). The buffering capacities of the solutions used in Groups 2 and 3 were 40 and 60 times, respectively, that of the solution used in Group 1. The average myocardial tissue pH at the end of 3 hours of ischemia was 6.54 ± 0.07 in Group 1, 7.23 ± 0.05 in Group 2, and 7.19 ± 0.06 in Group 3 (Group 1 significantly lower than Groups 2 and 3). Multidose infusion of a cardioplegic solution with low buffering capacity was unable to prevent the progressive development of tissue acidosis during 3 hours of ischemia. However, the multidose infusion of either blood-based or crystalloid solutions with high buffering capacity completely prevented any further reduction of tissue pH after the first 30 minutes of ischemia.

In all adult males and females of T. cristatus most of the long arm of chromosome 1 is achiasmate and heteromorphic with respect to Giemsa C-staining pattern. This heteromorphism correlates well with the heteromorphism seen by previous investigators on the lampbrush chromosomes of adult females. The heteromorphism has nothing to do with sex determination. All those fertile eggs of T. cristatus that develop normally beyond blastula are capable of development through to late tail-bud stage, but 50% of them arrest at late tail-bud and ultimately die. Homomorphism for the long arm of chromosome 1 can only be found in those embryos that arrest at late tailbud. The same findings apply to T. marmoratus, which also shows heteromorphism for chromosome 1, but not to T. alpestris, which has homomorphic chromosomes 1 and a potential 100% developmental success rate.

The recently cloned human beta-adrenergic cDNA and several mutated forms have been expressed in Xenopus laevis oocytes by injection of RNA made from the cDNA under the control of the bacteriophage SP6 promoter. The cDNA and gene of the beta 2-adrenergic receptor possess the unusual feature of having a second upstream ATG (-101 base pairs) and a 19-codon open reading frame 5' to the initiator methionine codon of the receptor (Kobilka, B. K., Dixon, R. A. F., Frielle, T., Dohlman, H. G., Bolanowski, M., Sigal, I. S., Yang-Feng, T. L., Francke, U., Caron, M. G., and Lefkowitz, R. J. (1987) Proc. Natl. Acad. Sci. U.S.A. 84, 46-50). RNA lacking this upstream AUG and open reading frame was translated approximately 10-fold more efficiently both in an in vitro rabbit reticulocyte system and in oocytes. Injected oocytes but not water injected controls expressed typical beta 2-adrenergic receptors as assessed by ligand binding (450 fmol/mg membrane protein) and catecholamine-stimulated adenylate cyclase (approximately 20 fold). Moreover, these receptors displayed typical agonist-induced homologous desensitization when oocytes were incubated with isoproterenol at room temperature for 3-24 h. Among a series of mutations, truncations of the membrane-anchored core of the receptor eliminated receptor binding and cyclase stimulating activity. In contrast, disruption of one of the cAMP-dependent protein kinase phosphorylation sites or removal of the serine/threonine-rich carboxyl terminus had little or no effect on these functions or on the extent of agonist-induced desensitization relative to that observed with native receptor. These studies validate the beta 2-adrenergic nature of the cloned human beta-adrenergic cDNA, document the utility of the Xenopus oocyte system for studying functional and regulatory properties of receptors coupled to adenylate cyclase, and suggest the possibility that elements in the 5' untranslated region of the beta 2-adrenergic receptor RNA may regulate its translation in vivo.

We have studied cyclic AMP-mediated regulation of the beta 2-adrenergic receptor (beta 2AR). The effects of cAMP were assessed in Chinese hamster fibroblast (CHW) cells expressing either the wild type human beta 2AR receptor (CH-beta 2) or mutated forms of the receptor lacking the consensus sequences for phosphorylation by the cAMP-dependent protein kinase. Treatment of the CH-beta 2 cells with the cAMP analogue dibutyryl cAMP (Bt2cAMP) induces a time-dependent "down-regulation" of the number of beta 2AR. This down-regulation of the receptors is accompanied by a decline in the steady state level of beta 2AR mRNA. Moreover, the treatment with Bt2cAMP induces an increase in the phosphorylation level of the membrane-associated beta 2AR. Both the reduction in beta 2AR mRNA and the enhanced phosphorylation of the receptor are rapid and precede the loss of receptor. The down-regulation of beta 2AR induced by Bt2cAMP is concentration-dependent and mimicked by the other biologically active cyclic nucleotide analogue, 8-Br-cAMP, by forskolin, and by the phosphodiesterase inhibitor, isobutylmethylxanthine. In the CHW cell lines expressing receptors lacking the putative protein kinase A phosphorylation sites, the Bt2cAMP-induced phosphorylation of beta 2AR is completely abolished. In these cells the down-regulation of beta 2AR receptor number produced by cAMP is significantly slowed, whereas the reduction in beta 2AR mRNA level is equivalent to that observed in CH-beta 2 cells. These data indicate that there are at least two pathways by which cAMP may decrease the number of beta 2ARs in cells: one involves phosphorylation of the receptor by the cAMP-dependent protein kinase and the other leads to a reduction in steady state beta 2AR mRNA levels.

Pathological changes in retinas of diabetics include specific morphological, biochemical, and functional abnormalities. As biochemical manifestations of the disease, increased sorbitol and decreased myo-inositol were found in retinas of experimentally diabetic animals. Similar alterations in polyol metabolism have been associated in nerves of diabetics with a reduction of Na+-K+-ATPase activity. To determine whether this association extends to the retinas of diabetic animals, we applied quantitative histochemical techniques to measure ATPase activities and the amounts of sodium and potassium in samples from nine individual layers of cryostat sections of rabbit retina. ATPase activities were determined fluorimetrically, and the ions were measured by atomic absorption with a carbon rod atomizer. The activity of Na+-K+-ATPase was reduced in the retinal pigmented epithelium (retinal pigment epithelium) and in selected layers of the neural retina, and total sodium in the retinal pigment epithelium layer was elevated in diabetes. The retinal pigment epithelium forms the outer component of the blood-retinal barrier and partly determines the composition of the retinal interstitial fluid. Changes in retinal pigment epithelium biochemistry and function might alter the intraretinal environment, predisposing neural retina or retinal blood vessels to disease. The morphologically and functionally well defined retinal pigment epithelium may provide a useful model for studying the pathogenesis of diabetic complications.

The use of pacemakers in the treatment of tachycardias is one of the most exciting and rapidly expanding applications of cardiac pacing. One of the more recent developments in this field has been the use of patient-activated radio frequency transmitted rapid atrial stimulation (RAS) in the treatment of paroxysmal supra-ventricular tachycardia (PSVT). Based on the previously established ability of asynchronous atrial pacing to interrupt a variety of re-entrant supraventricular rhythm disturbances, this modality of treatment is gaining increasing applicability in patients with PSVT associated with debilitating symptoms or other severe cardiovascular consequences in whom standard pharmacological regimens have either failed or are impossible to maintain for indefinite periods. This report describes our experience with five patients who underwent implantation of HAS units. The detailed electrophysiological studies required to ensure success and avoid any possible future complications are described. Over a follow-up period of four months to four years (mean 16 months) very few problems arose in the use of these units which have immeasurably improved the quality of life of the recipients. Our experience with RAS units has led to a few suggestions for future improvement and these are outlined in this report. The excellent patient acceptance and the reliability of this technique in terminating episodes of PSVT should, in the future, render RAS the treatment of choice in certain selected patients suffering form this common disorder.

Failure to reestablish blood flow to the subendocardium of the left ventricle may occur after prolonged myocardial ischemia and it has been suggested that edema may be responsible for this “noreflow” phenomenon. However, the process of ischemic contracture is also associated with prolonged myocardial ischemia and an inability to reperfuse the subendocardium. This study was designed to clarify the relative roles of edema and contracture in the pathogenesis of subendocardial “no-reflow.” This objective was achieved by determining the transmural distribution of tissue blood flow and water content across the wall of the left ventricle, in both the presence and absence of contracture, during the reperfusion phase after global myocardial ischemia of sufficient duration to exhaust myocardial anerobic metabolism. We made use of the fact that ischemic contracture can be inhibited in the intact canine heart by decreasing the temperature to a level of moderate hypothermia (28°C) in order to separate the variables of contracture and edema. We found that the subendocardial “no-reflow” phenomenon was present when contracture was present, but absent when contracture was absent. While edema, assessed by tissue water contents in excess of control values, was much greater in the deeper layers of the left ventricular wall in the absence of contracture than in its presence, there was no evidence that it impeded myocardial blood flow. Edema was indeed found to be greater in regions of greater flow. These findings challenge the concept that myocardial edema following ischemic arrest in cardiac surgery is directly responsible for inadequate reperfusion leading to necrosis.

An enzymatic assay for myo-inositol (MI) is described. The method is based on the oxidation of MI by NAD+-dependent myo-inositol dehydrogenase, coupled to reoxidation of NADH with oxalacetate and malate dehydrogenase. The resultant malate is measured fluorimetrically. Several variations of the assay are described for measuring MI in serum and in tissues in amounts ranging from 0.2 pmol to 8 nmol. Highest sensitivity is achieved by applying an oil-well technique for handling small droplets, and by using the principle of enzymatic cycling. The potential of the technique is illustrated by MI measurements in several tissues of normal and diabetic rats and Chinese hamsters.

Nick-translated 3H middle repetitive DNA (C0t 0.2–50) from Triturus cristatus carnifex was in situ hybridized to RNA transcripts on the loops of lampbrush chromosomes and to the denatured DNA in mitotic chromosomes from intestinal epithelium of the same species. In autoradiographs of lampbrush chromosomes only 20–40 pairs of loops were distinctly and in some cases heavily labelled after exposures of 4–14 d. Most of these fast labelling loops were located on the heteromorphic arms of bivalent I. After longer exposures, certain other loops appeared labelled, but few were so heavily labelled as those on chromosome I. There were fast labelling loops in positions corresponding to those of the nucleolus organizers on chromosomes VI and IX. The pattern of distribution of fast labelling loops was different on each of the heteromorphic arms of bivalent I. Some fast labelling loops were present on chromosome I of larger oocytes but not evident in smaller oocytes from the same animal. Some of the fast labelling loops were labelled only over part of their lengths. Partial labelling was seen over thick and thin halves of asymmetrical polarized loops and over short intermediate segments of some loops. — Autoradiographs of mitotic chromosomes showed patchy labelling of all chromosomes, but no distinctive pattern of labelling on chromosomes I. — These observations are discussed in relation to current ideas about the organization of DNA sequences in chromomeres and loops of lampbrush chromosomes, and it is proposed that the abundance of fast labelling loops on the heteromorphic arms of bivalent I may somehow be related to the absence of meiotic crossing over in these regions.

The value of selective, high injection rate, pancreatic pharmacoangiography was assessed in 114 patients. Opacification of the pancreas was graded on a 0-4+ scale. Selective injection of gastroduodenal and small pancreatic arteries gave the best results, 3.7+. Celiac injection rating without drugs was 0.9+, with epinephrine 2.2+, and with Priscoline 2.7+. Average ratings of hepatic artery injections were 2.6+ with epinephrine and 3.0+ with Priscoline; splenic artery injections were 2.5+ and 3.5+, respectively. Although superselective injection was possible in only 50% of the cases, addition of epinephrine and Priscoline resulted in an average grading of 3.4+ (yielding a preoperative diagnostic accuracy of 94%).

Using an intramyocardial pH needle probe (21 gauge) to monitor myocardial metabolism during ischemia, we determined the effect of potassium cardioplegia at both moderate and deep hypothermia. Five groups of 5 dogs each were placed on cardiopulmonary bypass and the pH probe was inserted approximately 10 mm into the left ventricular free wall. Cardiac ischemia was achieved by cross-clamping the ascending aorta at 37 degrees C (Group 1), 27 degrees C (Group 2), or 17 degrees C (Group 3). In the remaining two groups, aortic cross-clamping was followed by the infusion of 600 to 800 ml of potassium cardioplegic solution adjusted to cardiac temperatures of 27 degrees C (Group 4) or 17 degrees C (Group 5). In each group, myocardial temperature was maintained constant, electrical and mechanical activity observed, and pH recorded until a plateau was reached or for 3 hours. Our results show a progressive and significant decrease in the metabolic rate with reduction in temperature over the 37 degrees to 17 degrees C range. By abolishing contractile activity, potassium cardioplegia markedly reduces the rate of hydrogen ion accumulation at 27 degrees C, but at 17 degrees C the additive effect of cardioplegia is much less pronounced. These observations support the principle of reducing contractile activity to a minimum during elective arrest of the heart but indicate that potassium cardioplegia does little to further reduce the rate of anaerobic metabolism, as shown by the measurement of intramyocardial pH, under conditions of deep hypothermia.

A 19-year-old woman developed cardiorespiratory failure from multiple, peripheral pulmonary emboli apparently developing over the preceding 3 weeks. She was not considered to be an operative candidate. However, when 3 days of intravenous heparin infusion and 30 hours of membrane oxygenator support failed to improve the pulmonary pathology, pulmonary embolectomy was performed. The membrane oxygenator support had to be continued for 34 hours following the operation before it was successfully discontinued. The patient made a complete recovery.

Carbon furnace atomic absorption spectrometry was used to measure the Na and K content of freeze-dried microscopic tissue samples. This method was sufficiently sensitive to measure pmol amounts of Na and K from tissue weighing 10-60 ng. Within the spatial resolution of the microdissection procedure, ion diffusion that might occur during cryosectioning, freeze-drying, and dissection of the tissue did not seem to be a problem. Data obtained with this methodology were in agreement with previously reported values of the Na and K content of various tissues, thus supporting the usefulness of this quantitative histochemical technique.

The relative efficacy and safety of blood-based potassium cardioplegic solutions compared to crystalloid arresting solutions has been a major controversy in the field of intraoperative myocardial protection for cardiac operations. In this study multidose potassium (K+ = 30 mEq/L) blood cardioplegia was compared to multidose potassium crystalloid cardioplegia in a dog model in which hearts were arrested for periods of 4 1/2 and 6 hours. The cardioplegic solution was given as an initial bolus of 500 ml and then as 250 ml doses every 30 minutes of arrest. In the 4 1/2 hour arrest group, six animals received blood cardioplegia, six received a low-sodium crystalloid cardioplegia (modified Roe's solution), and 10 received a high sodium crystalloid cardioplegic solution of our own design. In the 6 hour arrest group, four animals received blood cardioplegia, four received the low-sodium solution, and four received the high-sodium solution. Myocardial temperature was precisely controlled at 27 degrees +/- 1 degree C in all groups. The hearts were reperfused for periods of 2 to 4 hours after the arrest periods and then examined morphologically for injury. The extent of myocardial damage was quantified in 5 mm thick transverse sections through the ventricles by using a tetrazolium enzyme-mapping technique. In the crystalloid groups the hearts arrested for 4 1/2 hours were significantly injured. The percentage (+/- SEM) of necrosis was 12.3 % +/- 5.6% in the low-sodium cardioplegic (modified Roe's) group and 9.3% +/- 3.4% in the high-sodium group. In the 6 hour arrest group the hearts were severely injured, with contracture occurring in all cases. The percentage of necrosis was 56.5% +/- 13% in the low-sodium cardioplegic group and 71.3% +/- 12% in the high-sodium group. In striking contrast all hearts protected with blood cardioplegia failed to show any evidence of tissue damage either on tetrazolium staining or on electron microscopic examination. We conclude that blood cardioplegia offers superior protection to the arrested heart at moderate hypothermia compared to crystalloid cardioplegia.

We studied eating behavior in two non-overlapping cohorts of consecutive patients electing gastric bypass surgery for obesity: 100 patients one year after operation and 60 patients three years afterward. Information was obtained through structured interviews and from office charts. Eating behavior was compared with previously collected data on 232 morbidly obese adults and 174 adults of normal weight. Despite an average weight loss of 100 lb (45 kg), there was little evidence of disturbed eating patterns among gastric bypass patients. Significantly fewer gastric bypass patients than morbidly obese comparison subjects reported frequent hunger, overeating, guilt about eating, or food preoccupation. Gastric bypass patients reported less preoccupation with food than did the normal-weight comparison subjects.

Ischemic contracture of the left ventricle ("stone heart") is a recognized complication of prolonged periods of interruption of the coronary circulation during open-heart surgery. We have examined the effects of moderate hypothermia (28 degrees C.) and preoperative beta-adrenergic blockade (propranolol, 0.5 mg. per kilogram; 1.0 mg. per kilogram) on contracture development during ischemic arrest of the heart. Four groups of 8 dogs each were placed on total cardiopulmonary bypass, and ischemic arrest of the heart was produced by cross-clamping the ascending aorta and venting the left ventricle. Intramyocardial carbon dioxide tension was continuously monitored by mass spectrometry. When anaerobic energy production ceased, as indicated by a final plateau in the intramyocardial carbon dioxide accumulation curve, the ischemic arrest was terminated and the contractile state of the heart observed. These results are given in the text. We conclude that beta-adrenergic blockade delays, but does not prevent, the onset of ischemic contracture of the left ventricle under normothermic conditions. Moderate hypothermia appears to prevent this complication completely.

Chromosomes and DNA sequence homologies have been studied in 15 species of North American salamander belonging to the genus Plethodon. These include 4 Eastern small species, 5 Eastern large species, 5 Western, and 1 New Mexican species. All species have 14 metacentric or sub-metacentric chromosomes. Their karyotypes are closely similar, but their C values range from 18–69 pg. DNA:DNA molecular hybridization studies showed that salamanders belonging to the same species group had between 60 and 90% of the observed repetitive DNA sequences in common, different groups of Eastern species had between 40 and 60% in common, and Eastern and Western groups had less than 10% in common. The slowly reassociating DNA sequences were also diverse among species, but higher levels of homology were observed than in the case of repetitive sequences. The New Mexican species was exceptional in showing little homology with other species with respect to either repetitive or slowly reassociating sequences.

A novel process has been developed for the manufacture of porous vascular grafts from solutions or melts of polymers. It allows the manufacture of grafts with controllable porosity, pore size, and mechanical properties. In this process, the polymer melt or polymer solution is extruded through fine orifices; the fibers are then fibers are then stretched and wound on a rotating mandril. Fiber-fiber bonding takes place, resulting in the formation of stable porous tubes. The effects of the process variables on the physical properties of the resulting graft have been studied and preliminary in vivo evaluation in dogs has demonstrated graft patency with a thin, stable neointima in both small (4 mm) and large (10 mm) caliber configurations.