Influence of serum on impaired neutrophil chemotaxis after thermal injury

Impaired neutrophil chemotaxis has been consistently documented after thermal injury but whether this defect is primarily related to an acquired cellular defect or to humoral factors is not clear. To study this question, serial neutrophil chemotaxis measurements using the agarose technique of chemotaxis, were made in 34 patients with a mean burn size of 33%. Eighty-three percent of these patients developed a neutrophil chemotactic defect at some time during their hospital stay. The results of this study indicated that the serum from burn patients did not contain cell-directed inhibitor(s) of chemotaxis (CDI) or chemotactic factor inactivator(s). Furthermore, the chemotactic defect in the burn patient's neutrophils could not be reversed by normal human serum, suggesting that the cause of this defect was not related to the absence of normal circulating humoral substances. Additionally, no suppressive effect of silvadene (10 g/ml) on neutrophil chemotaxis was found. Therefore, we concluded that stable serum factors were not likely to play a major role in the development of the acquired neutrophil defect thermal injury.     

Effect of LiCl on gastric acid secretion and mucosal barrier function

Lithium chloride (LiCl) has been shown to decrease gastric acid secretion and protect against ethanol-induced hemorrhagic gastritis in the rat. To further investigate these properties, two sets of experiments were performed in dogs with chronic Heidenhain pouches to study the effect of LiCl on histamine-stimulated gastric acid secretion and bile-induced disruption of the gastric mucosal barrier. In the first experiments the effect of LiCl on intravenous histamine-stimulated gastric secretion (40 micrograms/kg . hr) was determined. LiCl (30 mg/kg . hr) significantly reduced gastric acid secretion when compared to normal saline control (457 +/- 87 mueq H+/10 min versus 637 +/- 112 mueq H+/10 min, P less than 0.05). Serum and gastric lithium levels were determined and a significant inverse linear correlation existed between acid output and serum and gastric lithium levels. In the second set of experiments the effect of LiCl on bile-induced disruption of the gastric mucosal barrier was determined. Heidenhain pouches were continuously perfused with a pH 2 acid test solution and indices of mucosal barrier function (net acid back-diffusion and potential difference) were determined. LiCl (30 mg/kg . hr) significantly reduced both the increase in acid-back diffusion and the fall in potential difference with bile injury (5 mM taurodeoxycholate). In conclusion, these studies indicate that LiCl (1) decreases histamine-stimulated gastric acid secretion, and (2) diminishes bile-induced disruption of the gastric mucosal barrier in the canine Heidenhain pouch.     

Gram-negative infections of arterial substitutes

Enteric contamination at the site of a vascular injury creates a difficult management problem. In order to more intelligently approach this problem we have compared the efficacy of arterial autografts, autogenous vein graft, and polytetrafluorethylene (PTFE) grafts in wounds contaminated with enteric organisms. Thirty mongrel dogs were divided into three groups. Group I had both femoral arteries replaced with autografts, Group II underwent bypass grafting with 4-mm PTFE grafts, and Group III had femoral arteries replaced with autogenous vein grafts. The right groin was closed aseptically and served as a control while the left groin was contaminated with a standard aliquot of stool and then closed. The groups were observed for loss of blood flow, death due to hemorrhage, or complete healing. Termination of the study was determined by the first of these to occur in each animal. In the animals with arterial autografts, seven demonstrated healing and the average time to termination of the study was 20.2 days. Only one of the PTFE grafts healed and the average survival was 8.9 days. In the group with vein grafts, five healed. The time to termination was 14.7 days. These data demonstrated that arterial autografts are superior to PTFE grafts in an infected wound due to their ability to heal without disruption. This study suggests that autogenous tissue grafts are the prostheses of choice for replacement of small vessels injured in the presence of significant contamination.     

Proximal gastric vagotomy and mucosal antrectomy: a comparative physiologic examination

Proximal gastric vagotomy-mucosal antrectomy (PGV-MA) was devised in an attempt to reduce the cephalic and hormonal phases of acid secretion without disturbing gastric emptying. The current study determines the effects of proximal gastric vagotomy (PGV), or PGV-MA on acid secretion, gastrin, and gastric emptying. Twelve dogs underwent measurement of gastric emptying, fasting and postcibal acid production, and fasting and postprandial gastrin levels. The animals then underwent either PGV or PGV-MA and the studies were repeated. PGV markedly decreased basal acid (P less than 0.001); however, there was still a large postprandial acid increase. In contrast, PGV-MA nearly abolished both fasting and postprandial acid secretion (difference from control and PGV significant at P less than 0.001). Gastric emptying was not significantly altered by either procedure. PGV was associated with increased fasting and postprandial gastrin levels, while PGV-MA produced lower gastrin levels at all intervals than either controls or PGV-MA. PGV-MA emulates the effects of truncal vagotomy and antrectomy on acid secretion, without affecting gastric emptying and deserves further investigation as a possible surgical alternative in the treatment of duodenal ulcer disease.     

Prostacyclin increases gastric mucosa blood flow via cyclic AMP

Although prostacyclin has been shown to inhibit stress-induced gastric mucosal ulceration, the mechanism for this cytoprotection is unknown. This experiment measures the effect of intravenous prostacyclin on gastric mucosal blood flow and any modification of this effect by pretreatment with the phosphodiesterase inhibitor, theophylline. Miniature swine were anesthetized, intubated, and ventilated. Three groups of six animals each were studied: (1) theophylline, (2) prostacyclin, and (3) prostacyclin plus theophylline. After stabilization, baseline gastric mucosal blood flow was measured with radioactive spheres. Theophylline (or vehicle) was then infused at 50 mg/kg/hr × 15 min followed by 2 mg/kg/hr thereafter. After 30 min prostacyclin (or vehicle) was infused at 0.005, 0.05, and 0.5 μg/kg/min for three consecutive 15-min periods, each followed by measurement of gastric mucosal blood flow. Results: At 0.5 μg/kg/min, prostacyclin increased gastric mucosal blood flow despite a drop in mean arterial pressure (50.1 ± 8.4 vs 17.4 ± 4.1 ml/100 g/min). Significant differences in cardiac index were not seen among the three groups. Pretreatment with theophylline potentiated prostacyclin's effect on gastric mucosal blood flow suggesting that prostacyclin increases gastric mucosal blood flow by a mechanism dependent on cyclic AMP (113.2 ± 23.3 vs 50.1 ± 8.4 ml/100 g/min). Since mucosal ischemia is an accepted prerequisite for stress-induced ulceration, prostacyclin's effect on blood flow may contribute to its protective effect on gastric mucosa.     

Prostaglandin-induced bicarbonate secretion in the canine stomach: Characteristics and evidence for a cholinergic mechanism

Using a canine chambered stomach preparation, the effect of topical 16,16-dimethyl prostaglandin E₂ (dmPGE₂) in neutral solution (150 mN NaCl) on gastric mucosal bicarbonate (HCO₃^?) secretion was assessed. Compared to control studies in which neutral solution alone bathed the epithelium, dmPGE₂ (0.5, 1.0, 2.0, and 4.0 μg/ml), when applied to gastric mucosa, significantly increased the output of gastric HCO₃^? in a stepwise and dose-related fashion. Accompanying these effects in HCO₃^? output were similar increases in sodium, potassium, chloride, and gastric perfusate volume. In other studies, the effects of intravenous atropine and close intraarterial tetrodotoxin on this PG-induced HCO₃^? secretion were evaluated. Both agents completely prevented the stimulation of HCO₃^? output induced by dmPGE₂ (2 μg/ml). It is concluded that dmPGE₂, when topically applied to canine gastric epithelium, is a potent stimulant of bicarbonate output that is dose-dependent. The ability of atropine and tetrodotoxin to prevent this secretion suggests that a cholinergic mechanism may be involved and that dmPGE₂ mediates its effects on HCO₃^? output through acetylcholine release which in turn stimulates cholinergic nerve endings.     

Effects of indomethacin on blood flow in the normal pancreas in conscious dogs

In anesthetised animals basal pancreatic blood flow, both in the normal gland and in acute pancreatitis, and basal renal blood flow have been shown to be dependent on prostaglandins (PGs). However, in conscious dogs it has been demonstrated that the reliance of basal renal blood flow on PGs is only apparent, and probably due to the effect of anesthesia and surgery stimulating PG synthesis through enhanced stimulation of the sympathetic nervous system. This study was undertaken to investigate the changes in mean blood pressure, cardiac output, and pancreatic arterial blood flow, relative to the cardiac output, in the normal pancreas, with and without PG synthesis inhibition (indomethacin) in conscious dogs. Blood flows were measured with electromagnetic flow probes. The effects of indomethacin were measured over a 2-hr period and compared to a control group. The results show that the relative pancreatic blood flow is not affected by doses of indomethacin which decrease cardiac output (P less than 0.5). It is suggested that PGs may have no effect on blood flow in the normal pancreas in conscious animals.     

The biologic response to standard suture materials in the skin of fetal rabbits

It is thought that wound healing and reaction of tissue to suture materials in the newborn or preterm infant may resemble that of the fetus. Wound healing in fetal experimental animals has been described, but to date no study of reaction to suture material in fetal animals has been performed. Operations on 60 pregnant, New Zealand white rabbits were performed. Hysterotomies were performed, and a variety of sutures were simply placed in the skin in Group I. In Group II, a small skin incision was made, and the wound was closed with the various sutures. The suture materials studied were: silk, Prolene, Ethibond, chromic catgut, and Vicryl. The animals were sacrificed 2 to 5 days postoperatively, and histology and grading of the tissue reaction was carried out. Grading was based on: (1) reactive cellular density, and (2) cellular response dimension. The reaction observed in all fetuses was: (1) mild to moderate by our criteria, (2) identical with or without a wound, and (3) present 2 days after implantation and did not seem to change significantly thereafter. This study demonstrates a similar host-tissue response of the rabbit fetus to a variety of suture materials and suggests that any decision on the choice of suture material in the fetus and possibly the preterm and newborn infant should be based on properties of the suture other than the host-tissue response that the suture produces.     

Liver cell membrane alterations during hemorrhagic shock in the rat

Previous studies using the Ling-Gerard microelectrode to measure membrane potential and a muscle biopsy technique to determine water and electrolyte content have established a skeletal muscle cell membrane defect in hemorrhagic shock. The present study was undertaken to compare and contrast changes occurring on a cellular level in the liver and skeletal muscle of the rat during sustained hemorrhagic shock. The liver has been suggested as a possible primary site of organ failure during prolonged shock with a loss of normal liver processes and important hepatic metabolic functions. Thirty-four experiments were performed in rats with 11 experiments in the control group. Skeletal muscle membrane potential as well as liver cell membrane potential was measured after opening the abdomen through a midline incision. The ventral lobe of the liver was exposed and placed on a suspension apparatus to decrease respiratory interference and the liver was impaled with a Ling-Gerard microelectrode. Muscle cell resting membrane potentials were measured in exposed skeletal muscle in the leg of the animals. Biopsy samples were obtained at intervals in both the liver and skeletal muscle. Twenty-three experiments were conducted by producing hemorrhage with the withdrawal of blood over a 5- to 15-min period of time and maintaining a systolic blood pressure of 60 mm Hg for 115 ± 40 min. The distribution of water and electrolytes in intra- and extracellular space in the muscle biopsies as well as in the liver on the basis of chloride distribution was considered to be a passive phenomenon related to the resting cell membrane potential as predicted by the Nernst equation. Correction of the measured water and electrolyte content of the biopsies for residual blood was carried out with the use of chromium-51-tagged red blood cells. The control group of rats did not demonstrate any significant change in membrane potential of either muscle or liver cells during the experiment. The membrane potentials were maintained at normal levels in the muscle ?91.4 ± 2.2 mV; and in the liver at a mean of ?40.3 ± 3.3 mV. The hemorrhagic shock group of animals demonstrated significant changes. Muscle membrane potential decreased to ?80.99 ± 6.3 mV (P < 0.01) while at the same time period the liver membrane potential decreased to ?24.1 ± 4.6 mV (P < 0.001). The results of these experiments give further evidence of a cellular membrane defect in hemorrhagic shock. The liver cell membrane potential changes and accompanying water and electrolyte shifts occurred before any significant changes in the muscle tissue. The data indicate the existence of a major alteration in rat liver cell membrane function early in the shock state.     

Interorgan relationships of alanine and glutamine during fasting in the conscious dog

This study was designed to assess the interorgan relationships of glutamine and alanine in the conscious, overnight fasted dog, and to determine changes which occur with progressive fasting. Dogs were fasted for 18 hr (n = 6), 48 hr (n = 6), and 96 hr (n = 6) prior to the study. Catheters had been previously implanted in the femoral artery, renal vein, portal vein, and hepatic vein, and were used for blood sampling at 30-min intervals during the 3-hr experimental period. Hepatic and renal blood flows were determined by indocyanine green and para-aminohippuric acid (PAH) extraction methods, respectively. Balance data (micromoles/kilogram/minute) were estimated by multiplying the appropriate arteriovenous concentration differences by blood flows. Hepatic uptake of glutamine decreased 50% after a 48-hr fast, and by 96 hr, the liver became a net producer of glutamine. Gut utilization remained constant throughout fasting. The kidney's utilization gradually increased with fasting. The hepatic extraction of alanine fell with fasting, declining to 40% of its original uptake at 96 hr. The gut's production of alanine fell during the first 48 hr of fasting, but remained stable thereafter. The kidney's production of alanine increased throughout the period of starvation. The arterial concentration of glutamine rose with fasting, while that of alanine fell even with a 48 hr fast. The liver, by becoming a net producer of glutamine, and the kidney, by increasing its production of alanine, decrease demands for peripheral release of these two amino acids, and thus may have protein-sparing actions during fasting.     

HPLC for urinary catecholamines and metanephrines with alpha-methyldopa

In five healthy selected volunteers with normal blood pressure and one pheochromocytoma patient, high performance liquid chromatography (HPLC) has been evaluated, with electrochemical detection for quantitation of urinary catecholamines and metanephrines during administration of the antihypertensive, alpha-methyldopa. The clinical usefulness of HPLC is compared with that of the conventional assay method--the trihydroxyindole (THI)-fluorometric procedure. The THI fluorometric method is known to suffer from true false-positive interference as a result of its inability to differentiate between alpha-methyldopa, its primary metabolic derivatives, and the structurally similar endogenous catecholamines. It is shown that the HPLC separation methodology yields accurate, reproducible results devoid of interference from the presence of alpha-methyldopa. Free urinary excretion rates of epinephrine, norepinephrine, and dopamine were elevated by alpha-methyldopa, P less than 0.001, for epinephrine, norepinephrine, and dopamine when measured by the trihydroxyindole technique but not with high performance liquid chromatography. With alpha-methyldopa treatment, urinary normetanephrine excretion rates were slightly increased, P less than 0.05, by fluorometric analysis and slightly decreased. P less than 0.05, when measured by HPLC. Of added interest, the formation of the normetanephrine analog of alpha-methyldopa, previously undetected, is suggested. Slightly elevated metanephrine levels are seen by the THI-fluorometric method in the presence of alpha-methyl metanephrines. Establishing that the HPLC assay procedure is suitable for clinical diagnosis of pheochromocytoma, despite the presence of alpha-methyldopa, makes it unnecessary to discontinue use of this antihypertensive in screening for pheochromocytoma.     

Extraction of glutathione by the isolated perfused rabbit kidney

The effects of adding exogenous reduced glutathione (GSH) to the perfusate were studied in the isolated perfused rabbit kidney. The addition of 500 mg/liter of GSH to the perfusate prevented the depletion of cortical and medullary GSH; perfusion without the addition of GSH consistently resulted in depletion of tissue levels of this tripeptide. In addition, GSH supplementation of the perfusate decreased renal vascular resistance and increased perfusate flow. GSH extraction studies revealed a progressive decrease in renal extraction with time, ranging from complete extraction at 10 min to a value of 38% at 60 min. The fractional clearance of GSH increased from 7.3% at 10 min to 17.9% after 60 min of perfusion. The results indicate a high affinity of the rabbit kidney for GSH and a relatively large net reabsorption of the tripeptide.     

Detection of intestinal ischemia,I. Microardiological and temperature differences between mesenteric and antimesenteric margin of the small intestine of the rat

Microradiographs were made of the vasculature of the ileum of rats following an injection of micropaque. The radius of vessels entering the mesenteric margin of the rat small intestine decreases significantly during its course toward the antimesenteric margin. The relative lack of vascular supply in the antimesenteric region of bowel was associated with a significant reduction (P < 0.001) of mean surface temperature as compared to its mesenteric surface. Occlusion of the blood supply to the bowel wall abolished this temperature gradient (P < 0.1). Measurement of temperature differences between the mesenteric and antimesenteric margin of the bowel wall of man may prove to be a sensitive indicator of bowel viability in intestinal surgery.     

Role of mitochondrial enhancement in maintaining hepatic energy charge level in endotoxin shock

The purpose of this study is to clarify the nature of apparent abnormalities in fuel substrate utilization which occur during progressive endotoxin shock and to relate these findings with its implications for circulatory behavior. After the administration of endotoxin, marked differences appeared in the time courses of hepatic energy charge and mitochondrial oxidative and phosphorylative activities between the early stage with normal blood pressure and the late stage with low blood pressure. In the early stage, the hepatic energy charge was maintained at near normal levels with a concomitant enhancement in mitochondrial oxidative and phosphorylative activities. In the late stage, this enhancement of mitochondrial oxidative and phosphorylative activities was depressed concomitant with a fall in hepatic energy charge. The mitochondrial enhancement was further associated with a fall in mitochondrial redox state, a rise in ketone body formation, and normoglycemia, indicating an acceleration of free fatty acid β-oxidation and gluconeogenesis at the early stage. In comparison, mitochondrial inhibition was accompanied by a further fall in mitochondrial redox state and hypoglycemia, indicating an inhibition of gluconeogenesis at the late stage. It is suggested that an enhancement in mitochondrial oxidative and phosphorylative activities is a protective mechanism which compensates for the fall in hepatic energy charge, and thus plays an essential role in the survival and recovery.     

Metabolism of prostaglandins in human saphenous vein

The described methodology allows for analysis of metabolism of the prostaglandin PGH₂ in subcellular fractions (microsomes) obtained from human saphenous veins. Prostacyclin (PGI₂) synthetase as identified by its stable breakdown product 6-keto-PGF_1a is present in human saphenous vein. Thromboxane A₂ is absent. The enzymatic formation of PGE₂ was demonstrated by the addition of glutathione (GSH) indicating the presence of an active PGE₂ isomerase. The data suggest that the enzymatic endoperoxide-metabolizing pathways in human saphenous vein microsomes are prostacyclin synthetase and prostaglandin E isomerase. It is suggested that the ability of the vein graft to produce prostacyclin and PGE₂ may contribute to short- and long-term graft patency.     

Neutrophil function in adults after traumatic splenectomy

The syndrome of postsplenectomy sepsis in both children and adults is receiving increased clinical attention. However, the exact immunologic reasons for the increased susceptibility to bacterial sepsis after splenectomy is unclear. The purpose of the current report is to describe the results of studies of peripheral neutrophil function in 24 healthy adult individuals who had previously undergone incidental or traumatic splenectomy. The patient population studied had their splenectomies performed a mean of 6.8 years prior to the current study to avoid any bias resulting from the acute hospitalization or injury. None of the patients had underlying hematologic or malignant diseases. The results of these experiments indicate that peripheral neutrophil chemotaxis, phagocytosis, and intracellular killing of Staphylococcus are normal in this population, and additionally, that the sera of these patients adequately support the opsonization of S. aureus and generates chemotactic factors normally. No neutrophil defect or impairment of serum opsonic or chemotactic activity after incidental or traumatic splenectomy was identified in the population studied.     

The effect of epidermal growth factor on wound healing in mice

The data presented in this paper focus attention on the possible evolutionary advantages of communal licking, based upon the delivery of wound healing factors in the saliva to an immediate local injury. It is suggested that epidermal growth factor (EGF) is one of these factors, as topical application of EGF to a standardized back wound in mice caged separately enhanced wound closure in both control and sialectomized animals. A sex difference in the wound closing response was evident from these studies. The testosterone dependence of EGF synthesis and its action on wound closure as well as its release upon α-adrenergic stimulation, make teleological sense, in a context of an acute response to injury caused by fighting. It is also suggested that prostaglandins released in injured tissue may modulate these acute effects of EGF, as prostaglandin inhibitors prevented EGF-induced closure. Since EGF is known to be a potent mitogen for murine fibroblast and epithelial cell lines, it may also participate in longer term effects integral to wound healing.     

Functional preservation of the mammalian kidney. V. pharmacokinetics of dimethyl sulfoxide (1.4M) in kidneys (rabbit and dog) perfused at 37, 25, or 10 degrees C followed by transplantation (dog).

Rabbit and dog kidneys were perfused for 30 min at 37°C with 1.4 M [³H]Me₂SO in a K⁺-Mg²⁺?rich perfusate. Subsequently the kidneys were perfused for 30 min with Me₂SO-free perfusate. The rate of Me₂SO uptake and washout as well as Me₂SO distribution in the tissue were determined. It was found that equilibrium conditions were achieved within 30 min for both uptake and washout with $\text{T}\text{M}$ ratios approaching 1.0. The amount of Me₂SO in the cortex and medulla of rabbit kidneys was not significantly different. The same experiment was repeated with dog kidneys at 25 and 10°C. At these lower temperatures the rate of uptake and washout was significantly less, but the final concentration achieved within 30 min was the same as at 37°C. Dog kidneys flushed with a K⁺?Mg²⁺?rich solution, with or without 1.4 M dimethyl sulfoxide (Me₂SO), were kept at 10°C, then reimplanted in the autologous host, and an immediate contralateral nephrectomy was performed. Of the dogs receiving kidneys treated with Me₂SO-free solution, 86% survived; of the dogs receiving Me₂SO-treated kidneys, 75% survived. Dog kidneys were perfused for 30 min with a K⁺?Mg²⁺?rich solution, with or without 1.4 M Me₂SO, at 25 or 37°C. All kidneys were then perfused for 30 min with a Me₂SO-free solution at the same temperature used for the first perfusion. All kidneys were then reimplanted in the autologous host and an immediate contralateral nephrectomy was performed. Of the dogs receiving kidneys perfused at 25°C with Me₂SO-free solution, 43% survived; of the dogs receiving kidneys perfused with Me₂SO, 42% survived. Dog kidneys were also treated at 37°C in a manner similar to those at 25°C. Of the dogs receiving kidneys perfused at 37°C with Me₂SO-free solution, 80% survived; of the dogs receiving kidneys perfused with Me₂SO, 67% survived. Other results indicate that perfusion with a closed circuit is superior to perfusion with an open circuit. Also, gradual administration and washout of Me₂SO gives better renal survival than rapid changes in Me₂SO concentration.     

Zinc transport by the heart lymphatic system after acute myocardial infarction

Open-chest dog preparations were used to determine divalent cation transport following acute myocardial infarction. Cardiac lymph flow, lymph and plasma protein, zinc, calcium, and magnesium content and hemodynamic measurements were recorded every 20 min before and after coronary artery occlusion in sham operated (N = 4), infarcted (N = 6), and lymph-ablated animals (N = 4). During the 4-hr occlusion period, with constant blood pressure, lymph flow increased from 1.53 ± 0.25 to 2.15 ± 0.44 mg/hr (SEM), P < 0.01. Zinc decreased in plasma from 0.69 ± 0.10 to 0.41 ± 0.08 μg/ml, P < 0.01, and in lymph from 0.69 ± 0.08 to 0.40 ± 0.02 μg/ml, P < 0.01. Zinc to protein ratio decreased similarly to total zinc in plasma and lymph. Changes in calcium and magnesium were insignificant. Lymph to plasma concentration ratios increased for protein from 0.57 ± 0.05 to 0.62 ± 0.02, P < 0.05, and for zinc from 1.10 ± 0.26 to 1.21 ± 0.14, P < 0.05. Heart lymph clearance (lymph:plasma ratio × lymph flow) steadily rose for protein from 0.31 to 0.06 to 0.50 ± 0.08, P < 0.05, and for zinc from 0.59 ± 0.18 to 0.92 ± 0.15, P < 0.05. Lymph and plasma measurements did not change significantly in shamoperated animals. Plasma zinc remained unchanged from baseline after coronary occlusion in all lymphablated animals. The increased clearance of protein and zinc suggests that plasma proteins are zinc carriers after acute myocardial infarction and that the reduction of plasma zinc is dependent upon an intact cardiac lymphatic circulation.