Oxygen tension regulates the expression of angiogenesis factor by macrophages.

When cultured in a hypoxic environment similar to that found in the center of a wound, macrophages secreted active angiogenesis factor into the medium. Under conditions similar to those of well-oxygenated tissue, macrophages did not secrete active angiogenesis factor. Macrophages that secreted the factor at hypoxic conditions stopped secreting it when returned to room air. Thus the control of angiogenesis in wound healing may be the result of macrophages responding to tissue oxygen tension without the necessity of interacting with other cell types or biochemical signals.

Epidemiology of breast fluid secretion: association with breast cancer risk factors and cerumen type.

The epidemiology of breast fluid secretion was studied on the basis of nipple aspirates of breast fluid obtained from 3,929 nonlactating women of various racial groups. The results confirmed and extended earlier findings by our group: Variation in the proportion of secretors was related to most breast cancer risk factors, including age, race, age at menarche, age at first pregnancy, age at menopause, clinically diagnosed fibrocystic disease, menopausal estrogen use, and cerumen phenotype. Secretory activity as measured by nipple aspiration appeared to reflect hormonal and genetic effects on breast epithelium.

Wound oxygen levels during hyperbaric oxygen treatment in healing wounds.

Hyperbaric oxygen (HBO2) increases wound oxygen delivery, but few data quantify wound oxygen levels over the course of healing. We characterized these changes during and after HBO2 treatment in a rat wound model. The treatment group (n=7) received 2.0 ATA HBO2, 90 minutes BID for 15 days. Control rats (n=5) were only exposed to HBO2 during measurement. On days 5, 10, and 15, wound pO2 was measured before, during, and for an hour after HBO2 treatment. Both the peak pO2 and the pO2 one hour after HBO2 treatment were significantly greater than baseline on all days in both the treatment (p < .01) and control group (p < .05). The peak pO2 during HBO2 exposure and one hour after decreased significantly in the treatment group on day 15 compared to day 5 (p <.01, p <.05 respectively). No significant differences were found in pO2 values between days within the control group. These results demonstrate that both the peak wound oxygen levels and duration of elevation change significantly throughout the course of HBO2 treatment.

Wound collagen accumulation in obese hyperglycemic mice.

We used C57-BL ob/ob mice as a model to study wound healing in type II (adult-onset) diabetes. Planimetry was used to assess rate of closure in standard open skin wounds. In agreement with previous subcutaneous wound collagen-accumulation studies, closure was slower in the ob/ob mice. Subcutaneous implants were used to evaluate wound collagen accumulation. Weanling mice have collagen accumulation similar to lean littermates (mean 3.43 micrograms/cm vs. 3.46 micrograms/cm), but the same ob/ob animals had decreased wound collagen (mean 2.39 micrograms/cm vs. 3.02 micrograms/cm, P less than 0.04) when mature. Other ob/ob animals fed a restricted diet (and thus not obese) had normal collagen accumulation at the same age. Neither insulin nor diet restriction restored wound collagen accumulation in phenotypically obese mice. Because collagen accumulation is not improved by measures that control hyperglycemia (insulin and diet restriction) and the defect was seen only in phenotypically obese ob/ob mice, the decreased wound collagen accumulation may be due in part to structural changes in adipose tissue.

Jejunoileal bypass as a treatment of morbid obesity.

Seventy-five morbidly obese patients underwent jejunoileal bypass between December 1968 and October 1975. The average weight of 45 patients who had had the bypasses for over two years stabilized at 62.4% of the maximum preoperative value. Postoperative complications included recurrent diarrhea in 11% (8/74) and serum electrolyte deficits in 64% (48/75), most of which were transient. Potassium and calcium deficiencies were usually correctable by oral supplementation, but hypomagnesemia persisted in 23% (16/71) despite supplementation. Nine percent (4/43) had biopsy-proved hepatic cirrhosis after one year. Other complications were polyarthralgia, bone demineralization, renal stones, and vasculitis. Three patients required reanastomosis to original bowel continuity; all rapidly regained weight. One died of vasculitis and hepatic failure attributable to the bypass. Jejunoileal bypass is suitable only in morbidly obese patients with particularly high motivation, whose risk factors outweigh those risks incurred through bypass.

Adjuvant hyperbaric oxygen therapy (HBO2)for treatment of necrotizing fasciitis reduces mortality and amputation rate.

OBJECTIVE: A retrospective analysis of 42 patients with necrotizing soft tissue infections treated with adjunctive HBO2 to ascertain efficacy and safety. Overall mortality was 11.9% and morbidity 5%. SUMMARY BACKGROUND DATA: Necrotizing soft tissue infections have historically high rates of mortality and morbidity, including amputation. Common misconceptions that prevent widespread use of adjunctive HBO2 for this diagnosis include delays to surgery, increased morbidity, and significant complications. METHODS: Forty-two consecutive patients (average age 56.1) with necrotizing fasciitis presenting to a major referral center were treated with adjunctive HBO2 as part of an aggressive program of surgery, antibiotics, and critical care. Involved areas included the lower abdomen (15 patients), thigh and perineum (9 patients), flank (4 patients), lower leg (3 patients), and arm, shoulder, and axilla (2 patients). Co-morbidities included diabetes mellitus, chronic renal failure, intravenous drug abuse, peripheral vascular disease, and malignancy. RESULTS: Mortality was 11.9% (5 patients). Both amputations (a finger and a penis), occurred prior to transport to our facility. The average number of surgical debridements was 2.8 per patient; 1.25 performed prior to the start of HBO. The infectious process was controlled after an average of 7 HBO2 treatments were administered to ensure successful wound closure. Complications consisted of only mild ear barotrauma in 3 patients (7%), and confinement anxiety in 17 (41%) but did not prevent treatment. CONCLUSION: Compared to national reports of outcomes with "standard" regimens for necrotizing fasciitis, our experience with HBO2, adjunctive to comprehensive and aggressive management, demonstrates reduced mortality (34% v. 11.9%), and morbidity (amputations 50% v. 0%). The treatments were safe and no delays to surgery or interference with standard therapy could be attributed to HBO2.

Wound healing and aging.

There are "natural delays" in the healing of older individuals. Open wounds contract more slowly and incised wounds gain strength more slowly. Experimental studies indicate that cellular proliferation, wound metabolism, and collagen remodeling occur later in old animals. Clinical studies show, however, that operations can be performed safely in elderly patients and that the major increased risk to these patients is of nonwound medical complications that affect the wound.

Insulin-like growth factor binding protein-3 is present in the alpha-granules of platelets.

The lysis of the alpha-granules of platelets has been shown to release insulin-like growth factors (IGFs). One of the major regulators of the activity of IGFs is the IGF binding proteins (IGFBPs), but IGFBPs were thought to be absent from platelet alpha-granules. Human platelets were isolated, and the contents of the alpha-granules were released by thrombin digestion. IGFBP-3 was identified in the lysate by RIA and a ligand-binding Western blot; no other IGFBPs were observed. Platelet IGFBP-3 was present as the characteristic glycosylated doublet at 45 and 43 kilodaltons on ligand-binding Western blot, but was not associated with the acid-labile subunit in the alpha-granule. Thus, the IGFs in platelet alpha-granules coexist with IGFBP-3, which can play a major role in regulating and targeting the actions of IGFs when released by lysis.

Insulin-like growth factor-I reverses the impairment of wound healing induced by corticosteroids in rats.

Corticosteroids are widely used therapeutic agents that have as a major side-effect the impairment of wound healing. Two hypotheses were tested: 1) that antiinflammatory corticosteroids decrease the local insulin-like growth factor-I (IGF-I) response to injury; and 2) that locally administered IGF-I would overcome methylprednisolone-mediated suppression of healing. The IGF-I concentration was measured in fluid from wire mesh cylinder wounds in rats given saline or methylprednisolone im. Rats receiving 8 and 16 mg had decreased wound IGF-I levels of 32% and 56%, respectively, compared to the saline-injected controls. IGF-I was infused (15 micrograms/day) by osmotic minipumps into wire mesh cylinder wound chambers of methylprednisolone (8 mg)-treated rats for 7 and 14 days. Methylprednisolone decreased wound DNA to 21%, hydroxyproline to 30%, and total protein to 5% of the values found in saline-infused controls. A 14-day treatment with IGF-I completely reversed the effect of methylprednisolone and increased DNA, hydroxyproline, and total protein to 216%, 109%, and 96% of saline control values, respectively. In conclusion, corticosteroids depressed wound IGF-I concentrations in rats, and an infusion of IGF-I into wound chambers reversed the corticosteroid-induced impairment of wound healing, as determined by the DNA, hydroxyproline, and total protein contents in wound chambers.

Surgical wound infections: an overview.

There have been three major avenues by which control over infection has been increased: (1) Preservation of host defenses, (2) antisepsis and (3) asepsis. Despite the major successes we have had, infection remains the major limitor of surgical horizons. Asepsis, the newest but long the mainstay of infection control, has probably been developed to nearly its greatest capacity. Its forefronts lie in laminar flow ventilation, ultraviolet radiation and operating theater design, all expensive and relatively inefficient. Cost and the problem of endogenous bacteria limit further advances. Antisepsis, including preventive antibiotics, is also reaching its zenith. Resistant organisms, toxicity and cost limit further applications. We desperately need a "social contract" among surgeons to limit, by defined rules, the choice of agent, the total dose and the indications for use. Controlled studies of the effects of "preventive antibiotics" on hospital ecology and infection are needed. A return to antiseptics is being and should be explored. Preservation and enhancement of host defenses is the oldest but the most neglected of these ideas. It appears to be the most exploitable now. Enhancement by nutrition, maintenance of tissue perfusion, oxygenation and immune stimulation appear to have contributed to reduction of infection rates. More success in this area seems distinctly possible.

The role of nitric oxide in subcutaneous and transmural gut tissue oxygenation.

The influence of inhibiting the nitric oxide (NO) synthetase on tissue perfusion as indicated by tissue oxygen tensions was determined. Tissue oxygen probes were placed subcutaneously and on serosal and mucosal surfaces of colon of anesthetized adult rats. After a control period, the inhibitor of NO formation, N(G)-nitro-L-arginine methyl ester (L-NMMA), was given intravenously and followed 20 min later by infusion of substrate for NO synthetase, L-arginine. Mean arterial blood pressure (MAP), subcutaneous tissue oxygen tension (P(SQ)O2), serosal tissue oxygen tension (P SO(2)), and mucosal tissue oxygen tension (P(M)O2) were simultaneously measured. Baseline values for the measured parameters were MAP = 95 + or - 9 mmHg, P(SQ)O2 = 61 + or - 7 mmHg, P(S)O2 65 + or - 7 mmHg, and P(M)02 = 9 + or - 2 mmHg. The infusion of L-NMMA induced a significant increase in MAP to 123 + or - 7 mmHg (p < .001) and P(SQ)O2 to 72 + or - 7 mmHg (p < .001). P(S)O2 did not change significantly from baseline after L-NMMA infusion. A significant decrease in P(M)O2 to 4 + or - 2 mmHg was noted after L-NMMA infusion (p < .001). The administration of L-arginine promptly returned all measured parameters to baseline levels within 10 min of infusion. A transmural P(O2) gradient exists across the colon with P(M)O2 far lower than P(S)O2. P(SQ)O2 approximates P(S)O2 at baseline and P(S)O2 is not altered by inhibition of the NO synthetase. The 45% reduction in mucosal PO2 after L-NMMA, which was reversed by L-arginine infusion, suggests that nitric oxide participates in splanchnic vasomotor control with a preferential effect in the mucosal vasculature. The observed decrease in mucosal PO2 observed after inhibition of NO production is similar to the worsened hypoxia previously measured during hemorrhagic shock. Further work clarifying the local control mechanisms of gut tissue P02 can direct therapies to increase gut tissue oxygenation.

The dynamic properties of tissue oxygen in healing flaps.

Oxygen delivery to random pattern and musculocutaneous flaps was investigated in a canine model. Oxygen tension was measured in the proximal and distal portions of each flap and in adjacent normal skin by means of a recently developed technique. The effect of delay techniques on tissue oxygen tension was also examined with modifications of the same flap model. All measurements were made over a range of inspired oxygen concentrations (21% to 100%) both before operation and at intervals up to 15 days after operation. Tissue oxygen tensions were significantly higher in the musculocutaneous flaps than in random pattern flaps up to 6 days after operation. They were higher in the proximal portions than in the distal portions in each flap type. This difference was greater in the random pattern flap. Delay techniques prevented the early dramatic decrease in postoperative oxygen tension seen in random pattern flaps. Differences in the pattern of oxygen delivery to random pattern and musculocutaneous flaps may in part explain the greater reliability of musculocutaneous flaps when transposed in the presence of infection.

Regulation of wound-healing angiogenesis-effect of oxygen gradients and inspired oxygen concentration.

Tissue hypoxia is a well-known stimulus to angiogenesis. The central dead space in healing wounds has been shown to be hypoxic (PO2 = 1 to 10). Angiogenesis is a necessary component of all healing wounds. Rabbit ear chambers were used to explore the contribution of O2 gradients and various inspired oxygen concentrations on wound healing and angiogenesis. These experiments demonstrate that: (1) A hypoxic tissue gradient is mandatory for wound-healing angiogenesis, (2) when the hypoxic gradient is destroyed capillary growth cases, and (3) inspired oxygen concentrations affect the rate and density of capillary growth.

Selective effects of tumor necrosis factor-alpha on wound healing in rats.

Many growth factors are believed to act simultaneously in wounds. Tumor necrosis factor-alpha (TNF-alpha) is a cytokine released by activated macrophages. In various concentrations it has inflammatory, cytolytic, mitogenic, antitumor, and possibly angiogenic or antiangiogenic effects; therefore it is likely to affect wound healing. With stainless steel wire mesh wound cylinders implanted in rats, we tested topical TNF-alpha in wounds, alone and in combination with platelet-derived growth factor (PDGF) and transforming growth factor-beta (TGF-beta). The cylinders were injected daily for a total of 12 days, after which we measured the accumulation of protein, DNA, and hydroxyproline in each cylinder. TNF-alpha had little effect by itself; it inhibited the growth-promoting effects of TGF-beta, but it did not influence the effects of PDGF. These results agree with the in vitro studies showing synergism of TNF-alpha and PDGF and antagonism between TGF-beta and TNF-alpha. They also suggest that TGF-beta may have a negligible role in normal healing and emphasize that interaction of growth factors must be understood before appropriate clinical use can be planned.

Tissue oxygen tension and other indicators of blood loss or organ perfusion during graded hemorrhage.

Currently employed clinical indicators of perfusion provide inadequate warning of developing hazards caused by marginal perfusion in certain vital organs or "peripheral" tissues that are pivotal to postsurgical wound healing. In this study, mean arterial blood pressure, cardiac output, and transcutaneous and subcutaneous oxygen tensions (PtcO2 and PsqO2) were investigated during serial hemorrhage, as indicators of the degree of both hypovolemia and perfusion to specific tissues. Blood was removed in stages (10%, 20%, 30%, 40%, 55%, 60%, and 65% of original volume) from anesthetized dogs. Injections of variously radiolabeled microspheres allowed assessment of blood flow at each stage of hemorrhage in bone, brain, colon, heart, kidney, liver, muscle, pancreas, skin, small intestine, spleen, stomach, and subcutaneous tissue. PsqO2 was correlated more highly with blood volume lost than was PtcO2. Furthermore PsqO2 was more sensitive to blood loss than was either cardiac output or PtcO2 and, also during the early loss (0% to 40%), was more sensitive than mean arterial pressure. Some organs (e.g., pancreas) appeared to lose considerable blood flow with only small loss of blood volume, but their blood flow then stabilized at a low level despite further hemorrhage. Other organs, notably the kidney, appeared to be relatively unaffected by substantial loss of blood volume (20% to 40%), after which, however, their blood flow quite abruptly became sensitive to further hypovolemia. This explains why blood flow-related performance of the kidney (e.g., urine volume) may not adequately predict a developing hazard or peripheral perfusion. Some indicators were found to be better indexes of blood flow in some organs than in others (e.g., cardiac output and PsqO2 correlated more closely with skin, spleen, and intestinal flows [and one another] than with vital organ flows).

Subcutaneous tissue oxygen tension falls during hemodialysis.

The effect of hemodialysis on subcutaneous tissue oxygen tension was studied in nine patients. During hemodialysis, blood pressure decreased, pulse increased, and all patients lost weight. Arterial blood oxygen tension fell insignificantly, from 79 to 73 mm Hg. Subcutaneous oxygen tension decreased from 52 to 28 mm Hg (p less than 0.001). Because adequate tissue oxygenation is necessary for wound healing and resistance to infection, we postulate that hemodialysis may contribute to the wound morbidity frequently seen in dialyzed patients.

Studies on inflammation and wound healing: angiogenesis and collagen synthesis stimulated in vivo by resident and activated wound macrophages.

Wound inflammatory cells were harvested by aspiration of fluid from the "dead space" of subcutaneous rabbit wounds and transplanted into the cornea where, compared with suitable controls, they stimulated healing (i.e., angiogenesis, fibroplasia, and new collagen synthesis, which led to formation of visible, vascularized scar tissue). Analysis of the data and the literature supports the conclusions that: (1) inflammatory cells control the continuation of the repair process after the immediate effects of injury subside; (2) macrophages, as opposed to granulocytes, appear to be the major contributors; (3) activated by their presence in the wound, macrophages release substances that stimulate fibroplasia, collagen synthesis, and angiogenesis in vivo; and (4) tissue injury is not a maximum stimulus to repair, since endotoxin-treated macrophages have increased capacity to stimulate collagen synthesis and angiogenesis. A hypothesis is offered to explain the notorious clinical discrepancy between the extent of injury and the extent of repair.

Effects of caffeine-free diet on benign breast disease: a randomized trial.

There is considerable interest in the potential effect on benign disease of a diet free of methylxanthines (caffeine, theophylline, and theobromine) found in coffee, tea, colas, and chocolate. We randomly assigned 158 women who presented with a breast concern either to a group encouraged to abstain from methylxanthine-containing foods and beverages or to a group who received no dietary recommendations (controls). At the initial visit each patient's sociomedical history and data on methylxanthine consumption were obtained by interview, and clinically palpable breast findings were graded on a scale of 0 to 4 (no nodularity to confluent hard "dysplasia") for each quadrant of both breasts. On the follow-up visit approximately 4 months later similar information was obtained. Mammograms were taken at both visits for a subset of women in each group. We found a statistically significant reduction in clinically palpable breast findings in the abstaining group as compared with controls, but the absolute change was minor and may be of little clinical significance. Comparison of before-after mammograms offered little support for the methylxanthine hypothesis. There was no relation between clinically palpable breast finding scores at initial examination and caffeine consumption levels reported at that time.

Vitamin E and benign breast "disease": a double-blind, randomized clinical trial.

We report here the results of a double-blind, randomized trial of the effect of vitamin E on clinically palpable benign breast findings. Seventy-three women who attended a breast screening clinic were assigned randomly to either a daily regimen of 600 IU vitamin E (n = 37) or a placebo (n = 36). At the initial visit sociomedical information was obtained for each patient and breast examination performed, with a score ranging from 0 to 4 recorded for each quadrant of both breasts. Thirty-two women in the vitamin E group and 30 in the placebo group returned for follow-up breast examination approximately 2 months later. Scores for mean ages and breast findings at entry were similar for women in the two groups. We found no differences between the vitamin E and placebo groups in scores for changes in breast findings at the end of the study period and no differences in the proportion of women who reported feeling less premenstrual pain (40.0% and 41.4%, respectively). We conclude that in this group of women with breast findings, most of which were not currently serious enough to warrant biopsy, there was no beneficial effect of vitamin E taken during a 2-month course.

The effect of alpha-adrenergic blockade on cardiac performance and tissue oxygen delivery during excision of pheochromocytoma.

To establish criteria for administration of the optimal dose of alpha-adrenergic receptor blocking drugs, we studied cardiac performance and tissue oxygen tension in three patients who underwent excision of pheochromocytoma. Subcutaneous oxygen tension was measured by the method of Niinikoski and Hunt. Cardiac function was assessed by thermodilution cardiac output, systemic and pulmonary arterial blood pressures, and continuous two-dimensional transesophageal echocardiography of a cross section of the left ventricle at the level of the papillary muscles. Despite large changes in cardiac output and systemic, pulmonary, and wedge pressures, intraoperative tissue oxygen tensions and ejection fractions remained normal (even at times of peak catecholamine excretion and very abnormal wedge pressures). Studies of healthy animals that received no alpha-adrenergic receptor blocking drugs showed major decrements of tissue oxygen in response to modest doses of epinephrine. We conclude that progressive administration of alpha-adrenergic receptor blocking drugs does not absolutely protect the patient from major changes in blood pressure during operation for pheochromocytoma, but that cardiac performance and oxygen supply to the tissues are unimpaired.