Exact energy spectrum of a two-temperature kinetic Ising model

We develop the exact energy spectrum for a two-temperature kinetic Ising spin chain and its dual reaction-diffusion system with spatially alternating pair annihilation and creation rates. We also discuss the symmetries of the system pseudo-Hamiltonian and their role in developing a general solution. The surprisingly simple form for the eigenvalues leads to interesting physical consequences and to a possible numerical analysis of the dynamical properties of the system.

Malrotation discovered during routine radionuclide gastric emptying study

In infants with recurrent vomiting, and especially bilious vomiting, the algorithmic approach is to perform conventional barium upper gastrointestinal radiography to rule out malrotation and midgut volvulus, which are surgical emergencies. However, children with protracted vomiting and failure to thrive are candidates for medical treatment. These children are often evaluated by radionuclide gastric emptying studies to assess gastric emptying. Three patients are presented in whom the radionuclide gastric emptying study revealed the presence of a malrotation anomaly which had been undetected by antecedent barium gastrointestinal radiographic studies.

A continuing medical education strategy for care of the elderly by the surgical specialties

As the absolute numbers and percentage of older people rises in Canada, surgeons are required to treat an increasing number of elderly patients. Recognizing the need to enhance the quality of health care for these people by continuing medical education of health care professionals, the Canadian Medical Association sponsored an invitational workshop in May 1992. The workshop group addressing surgery and its specialties identified three essential underprinnings: knowledge of the aging process (altered physiology and response to illness); decision analysis for interventions (risks, benefits and ethical dimensions); and communication skills. Three priorities for continuing education were recommended: improving knowledge of the physiologic changes that impact on the recovery of elderly patients from surgery; management of postoperative care; and improved knowledge and skills in prescribing medications for older surgical patients. Strategies to implement these priorities are outlined.

Colorectal and gynecological malignancies: comparison of B72.3 monoclonal antibody imaging, CT, and serum tumor antigens

Noninvasive B72.3 monoclonal antibody imaging provides beneficial information that may influence therapeutic and surgical decisions, and may clarify other clinical, laboratory, and CT scan findings. Intraoperative localization of tumor sites with a hand-held gamma probe holds promise as a further advantage of this technique.

Quantitative bone gallium scintigraphy in osteomyelitis

Gallium imaging offers many practical advantages over indium-111-labeled leukocyte imaging, and calculating quantitative ratios in addition to performing the routine bone-gallium images allows accurate and easy evaluation of patients with suspected osteomyelitis. To add objectivity and improve the accuracy and confidence in diagnosis of osteomyelitis, quantitative comparison of abnormalities seen on bone scans and gallium scans was performed. One hundred and ten adult patients with 126 sites of suspected osteomyelitis were evaluated and categorized by gallium-to-bone ratios, gallium-to-background ratios, and spatial incongruency of gallium and bone activity. Combined evaluation using these criteria gave a 70% sensitivity and 93% specificity for the diagnosis of osteomyelitis.

Vagotomy and antrectomy revisited

A retrospective review of 185 patients who underwent truncal vagotomy and antrectomy for duodenal ulcer disease was carried out to determine the mortality and morbidity of the procedure. There were no deaths within 30 days of operation and only one patient died while in the hospital (0.54%). Twenty-one patients (11.4%) suffered early morbidity, 3 of them requiring a second operation. Follow-up was obtained in 83 patients and averaged 13.5 years. According to Visick's classification 75 patients (90.4%) were in class I or II; 5 patients (6%) were in class III and 3 patients (3.6%) in class IV. A recurrent ulcer developed in 2 of the 83 patients. In contrast, after highly selective vagotomy, the literature supports an unacceptable incidence of recurrent ulcer. Therefore, we must not prematurely cast aside vagotomy and antrectomy; it still remains a safe and acceptable procedure for duodenal ulcer disease.

Natural history of in situ breast cancer in a defined population

The entire experience of in situ breast cancer in Alberta from 1953 to 1984 was examined. Of 243 patients coded, 226 were available for review by a panel of three pathologists. In 149 cases the diagnosis of in situ disease was confirmed. One hundred and eight patients had 109 ductal carcinomas in situ, 38 patients had lobular carcinomas in situ, with 3 patients having both. A multitude of treatments was used, ranging from local excision to radical mastectomy. Survival at a mean of 6 years follow-up was equal in all groups, with only two patients with a confirmed diagnosis of ductal carcinoma in situ dying from clinically suspected systemic disease. In patients treated by local excision, ipsilateral cancers were seen in 12% of ductal carcinoma in situ patients who had local excision and 13% of patients with lobular carcinoma in situ. Contralateral metachronous invasive cancers were seen in 6% of ductal carcinoma in situ patients and 3% of lobular carcinoma in situ patients. No lymph node involvement was seen in any of these patients, either with prophylactic dissection or in follow-up. The conclusion reached was that both in situ lesions are similar in their clinical course. Lymph node dissection is not necessary. Pathologic review is critical for accurate studies, with a change in diagnosis of 36% of diagnoses. Treatment does not appear to affect prognosis. The most appropriate treatment needs to be determined in prospective randomized trials.

The effect of mechanical stress on soft and hard tissue repair; a review

The influence of mechanical forces on intact tissue is well established. A growing body of evidence demonstrates that healing wounds also respond to the functional demands of their mechanical environment. At the present time, an understanding of the fundamental mechanism by which mechanical stress affects tissues and wounds remains elusive.

Etiology of late developing incisional hernias--the possible role of mechanical stress

The etiology of incisional hernias that develop a year or more after laparotomy is not understood. This subset of incisional hernias is not associated with the etiologic factors usually implicated in incisional hernia formation. Mechanical stress is known to have a profound influence on the structure of both normal and wounded tissue. It is hypothesised that mechanical stress plays an important role in the development of late incisional hernias.

Presidential address, 1986. The future of general surgery

The future of general surgery is assured provided the discipline remains flexible, adaptable and innovative. A strong and continuing emphasis on education and continuing emphasis on education and research at all levels is essential to maintain these qualities.

Experimental wound healing: increased breaking strength and collagen synthetic activity in abdominal fascial wounds healing with secondary closure of the skin

Delayed primary closure or secondary closure of skin and subcutaneous fat in contaminated laparotomy incisions virtually eliminates the risk of wound abscess in clinical practice. Incisional hernias rarely develop in these wounds. This experimental study offers a possible explanation. Longitudinal incisions in the linea alba of female Wistar rats healed under skin incisions which were either sutured ('closed' subgroup) or left to close by secondary intention ('open' subgroup). Postoperative breaking strengths and collagen contents (measured as hydroxyproline) were studied at intervals of 3-120 days. Measurable strength developed by 5 days, at which time 'open' subgroup wounds were found to be weaker and to have less collagen. At all other times, however, 'open' subgroup wounds were stronger, a property which could be ascribed at earlier, but not at later, periods (42 or 120 days), to a higher content and concentration of collagen. At 3 days the rate of collagen production was significantly (P less than 0.025) lower in 'open' than in 'closed' subgroup wounds but the converse was true at 6 and 9 days (P less than 0.025), thus accounting for the changes in biomechanical properties. It is suggested that initially the stimulus for collagen synthesis is greater in the 'open' wounds and this leads to the development of a collagenous structure which is better adapted to resist tensile forces.

Effects of two "lipid-lowering" diets on plasma lipid levels of patients with peripheral vascular disease

Fifty subjects with peripheral vascular disease were randomly assigned to either the American Heart Association Hyperlipidemia Diet C (AHA, N = 23) or a higher fiber, low fat diet based on the Pritikin maintenance diet (HFD, N = 27) and studied for a 12-month period. Diet counseling was provided, and the subjects were encouraged to exercise regularly, to decrease their consumption of salt, alcohol, and caffeine, and to restrict cigarettes as much as possible. Dietary intake data showed that energy distribution was approximately 49% and 64% carbohydrate, 20% and 22% protein, and 31% and 14% fat for the AHA and HFD groups, respectively. Cholesterol and dietary fiber intakes averaged 201 mg and 23 gm per day, respectively, for the AHA group and 108 mg and 43 gm per day, respectively, for the HFD group. Generally, both groups showed tendencies toward decreased serum triglycerides, cholesterol, and LDL cholesterol and increased HDL cholesterol. The HFD group achieved a significant decrease in serum cholesterol (at month 12) (p less than .01). The only significant between-group difference was in serum cholesterol at 4 months (p less than .01), with the lower value in the HFD group. There was a consistent negative correlation between dietary fiber and serum cholesterol levels (p less than .01). Average weight loss was 4.1 kg for the AHA group and 6 kg for the HFD group. We concluded that both dietary regimens, combined with exercise, can be of benefit to patients with peripheral vascular disease.

Skin blood flow during histamine flare using the clearance of epicutaneous applied Xenon-133 in diabetic and non-diabetic subjects

The increase in skin blood flow produced by both reactive hyperemia and histamine was examined in 8 normal, 8 diabetic and 3 cancer patients using the epicutaneous Xenon-133 clearance method. The histamine flare response in both diabetic and cancer groups was reduced compared to that in the normal group. There was no significant difference in the reactive hyperemia responses. It is concluded that the reduction in the histamine flare response is due to a defect in the sensory nerves mediating the axon reflex and not due to a change in the vascular response.

Primary and secondary healing in infected wounds. An experimental study

The beneficial effects of delayed closure of contaminated wounds are recognized, but not well defined. Rats with abdominal incisions were infected with Staphylococcus aureus or Escherichia coli and then subgrouped for primary or secondary healing. Noninfected rats served as controls. Between seven and 119 days later, the wounds were subjected to breaking-strength determination, hydroxyproline analysis, and light and scanning electron microscopy. In the controls, secondary closure gave stronger wounds than primary closure. In those infected with S aureus the wounds were stronger than in the primary-closure control group, regardless of the closure method. Of the E coli-infected wounds those primarily closed were weaker than those secondarily closed. Secondary closure gave infected wounds fewer complications. Biochemical and microscopic examination did not explain these findings.

Elastin and granulation tissue

The contraction of granulation tissue is an important factor in wound healing. The tract of an abdominal drainage tube closes at the rate of 1 mm/h once the tube is removed. Specialized myofibroblasts are generally believed to be responsible for this process and the presence of elastin in granulation tissue has been debated for many years. A 3-mm polyethylene tube was inserted through the left lobe of the liver in 41 rats. A tube of granulation tissue formed around the plastic. This granulation tissue was isolated, after periods ranging from 8 to 20 days, by removing the left lobe of the liver and scraping away the surrounding liver tissue. Biochemical assay for elastin revealed that normal hepatic tissue does not contain any detectable amount of elastin. All 41 samples of granulation tissue contained elastin with a mean value of 8.5 X 10(-6) g of elastin per milligram of tissue. Normal rat aorta contains 31.4 X 10(-6) g of elastin per milligram of tissue. These tubes of granulation tissue were histologically normal and the presence of elastin was recognized using elastin stains. The exact role of elastin in granulation tissue is uncertain but this experiment clearly demonstrates its generation and presence there.

Calf blood flow and ankle systolic blood pressure in intermittent claudication monitored over five years

The response of calf blood flow and ankle blood pressure to 2 minutes of ischemic exercise were recorded every 6 months over a 5-year period in 9 patients with intermittent claudication who were treated conservatively on a regime including alpha tocopherol. No statistically significant change was noted in the pattern of the calf blood flow response over this period. Statistically significant (P less than 0.05) increases in resting and minimal postexercise ankle systolic pressures were partially attributable to a concomitant increase in central arterial pressure as indicated by brachial systolic pressure. Results from 18 patients over 1 year and from 14 patients over 2 years are consistent with these findings. The evidence presented suggests that the arterial disease process was stable over this period.

Surgical treatment of the thoracic outlet compression syndrome

Narrowing of the thoracic outlet may give rises to symptoms in the arm from compression of the nerves, the subclavian artery, and the subclavian vein. Anatomic studies show that nerve compression may affect fibers from T-1, C-8, and not infrequently C-7, providing an explanation for the diffuse nature of the nerve symptoms in the arm. Relief from this compression at the thoracic outlet is readily accomplished by transaxillary resection of the first rib together with any associated cervical rib, fibrous cervical rib analogues, or other fibrous bands encroaching on the neurovascular structures. A study of 40 patients with the syndrome who were treated in this way and followed up after an interval of three to ten years shows that those with nerve and vein symptoms can expect a good result but the results of treatment in those with arterial symptoms is less satisfactory.

A morphologic study on the effect of suturing the submucosa of the large intestine

Five suture materials, chromic catgut, braided silk, Prolene, Teflon coated braided Dacron and Dexon have been examined morphologically for their effect on the submucosal collagen structure of the large intestine. The rougher surfaced materials, such as catgut, braided silk and Dexon, cause considerable damage to the submucosa on either side of an intestinal anastomosis. Because of this damage, it would appear that these sutures are more likely to jeopardize the integrity of an intestinal anastomosis.

Normal processes and restraints in wound healing

Wound healing normally follows an uninterrupted course but, for the purposes of description, it can be considered in four phases -- hemostasis, acute inflammation, repair and consolidation. Arrest of healing may occur at any phase and lead to a number of clinical problems. Repair cannot begin until the phase of acute inflammation has begun to subside; this fact is of special importance in clinical surgery. Wound healing in gastrointestinal tract and abdominal incisions is emphasized because healing problems are common in these areas and failure to heal results in morbidity and a regrettable mortality.

Bacterial peritonitis and the bursting strength of intestinal anastomoses

In order to study the bursting strength of intestinal anastomoses, resection of a wedge of ileum and creation of an anastomosis were performed, and peritonitis was induced in five groups of rats. Peritonitis was induced by intraperitoneal injection of bacterial suspensions of Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Clostridium welchii, and the exteriorized ileal loop in each rat was regularly inspected for peritoneal exudation, adhesions, hyperemia, obstruction, leakage and bursting strength. All bowel anastomoses performed in the presence of peritonitis were weaker than those done in a sterile field (control group) and the type of organism influenced the strength of the anastomosis and the histopathologic changes; in this study the weakest anastomoses were associated with E. coli infection.

The management of congenital hydronephrosis in the newborn

Hydronephrosis due to pelvi-ureteric obstruction rarely presents in the neonatal period. When it does, the disease is advanced and it may be advisable to drain the obstructed kidney until the child is old enough and fit enough to withstand a pyeloplasty. In this paper 2 cases of neonatal hydronephrosis are reported and a satisfactory method of drainage is described.

Some aspects of abdominal surgery in the elderly patient

Most operations on elderly patients are of an urgent nature. If time permits, measures to improve cardiac, respiratory and renal functions in the appropriate ways should be undertaken. During recovery from anesthesia careful but adequate sedation will reduce the risk of myocardial ischemia. Throughout the postoperative period constant encouragement of the older patient is particularly helpful.Transverse abdominal incisions and the frequent use of temporary gastrostomy are advocated.External hernia, hiatus hernia, peptic ulcer, carcinoma of the stomach, biliary disease, appendicits, intestinal obstruction, and carcinoma of the large intestine are discussed specifically, with special reference to the practical details of management in the elderly patient.