Facing Trauma and Surgical Emergency in Space: Hemorrhagic Shock

Although the risk of trauma in space is low, unpredictable events can occur that may require surgical treatment. Hemorrhage can be a life-threatening condition while traveling to another planet and after landing on it. These exploration missions call for a different approach than rapid return to Earth, which is the policy currently adopted on the International Space Station (ISS) in low Earth orbit (LEO). Consequences are difficult to predict, given the still scarce knowledge of human physiology in such environments. Blood loss in space can deplete the affected astronaut’s physiological reserves and all stored crew supplies. In this review, we will describe different aspects of hemorrhage in space, and by comparison with terrestrial conditions, the possible solutions to be adopted, and the current state of the art.

The Role of DAMPS in Burns and Hemorrhagic Shock Immune Response: Pathophysiology and Clinical Issues. Review

Severe or major burns induce a pathophysiological, immune, and inflammatory response that can persist for a long time and affect morbidity and mortality. Severe burns are followed by a "hypermetabolic response", an inflammatory process that can be extensive and become uncontrolled, leading to a generalized catabolic state and delayed healing. Catabolism causes the upregulation of inflammatory cells and innate immune markers in various organs, which may lead to multiorgan failure and death. Burns activate immune cells and cytokine production regulated by damage-associated molecular patterns (DAMPs). Trauma has similar injury-related immune responses, whereby DAMPs are massively released in musculoskeletal injuries and elicit widespread systemic inflammation. Hemorrhagic shock is the main cause of death in trauma. It is hypovolemic, and the consequence of volume loss and the speed of blood loss manifest immediately after injury. In burns, the shock becomes evident within the first 24 h and is hypovolemic-distributive due to the severely compromised regulation of tissue perfusion and oxygen delivery caused by capillary leakage, whereby fluids shift from the intravascular to the interstitial space. In this review, we compare the pathophysiological responses to burns and trauma including their associated clinical patterns.

Emergency surgery in the time of Coronavirus: the pandemic effect

BACKGROUND

The COVID-19 epidemic became a challenge for Emergency Departments (ED) and a remarkable reduction in surgical emergencies has been widely noticed. The aim of the present study was to evaluate the impact of the pandemic period in the need of surgical emergencies.

METHODS

Between January 1, and May 31, 2020 all the consecutive general surgery emergencies performed by the Unit Hospital Emergency Surgery of the Careggi University (Florence, Italy) were prospectively recorded and compared to the same period of 2019. Demographic and clinical data were recorded and analyzed.

RESULTS

The number of surgical procedures decreased only in the month of March 2020 (compared to 2019), while in April the total numer of emergency surgical procedures was similar. Only appendectomy, complicated hernia repair and colonic resection were significantly reduced (40%, 48% and 33% respectively). The number of small intestine excision, cholecystectomy and lysis of peritoneal adhesions remained stable throughout the entire period. No statistically significant differences were found considering age, sex, Emergency Surgery Score, mortality, ICU postoperative admission and time between admission and surgery, even when analyzed with multivariate analysis for every single surgical procedure, suggesting a comparable disease severity and comorbility patterns. Mortality in COVID patients was 25%, compared to 7% of no-covid patients.

CONCLUSIONS

The COVID-19 pandemic has caused major changes in daily clinical practice, especially in areas such as Emergency. This has led to a temporary reduction and changes in the flow of patients to the emergency room, with implications also for emergency surgical activities.

Emergency surgery in the time of Coronavirus: the pandemic effect

BACKGROUND

The COVID-19 epidemic became a challenge for Emergency Departments (ED) and a remarkable reduction in surgical emergencies has been widely noticed. The aim of the present study was to evaluate the impact of the pandemic period in the need of surgical emergencies.

METHODS

Between January 1, and May 31, 2020 all the consecutive general surgery emergencies performed by the Unit Hospital Emergency Surgery of the Careggi University (Florence, Italy) were prospectively recorded and compared to the same period of 2019. Demographic and clinical data were recorded and analyzed.

RESULTS

The number of surgical procedures decreased only in the month of March 2020 (compared to 2019), while in April the total numer of emergency surgical procedures was similar. Only appendectomy, complicated hernia repair and colonic resection were significantly reduced (40%, 48% and 33% respectively). The number of small intestine excision, cholecystectomy and lysis of peritoneal adhesions remained stable throughout the entire period. No statistically significant differences were found considering age, sex, Emergency Surgery Score, mortality, ICU postoperative admission and time between admission and surgery, even when analyzed with multivariate analysis for every single surgical procedure, suggesting a comparable disease severity and comorbility patterns. Mortality in COVID patients was 25%, compared to 7% of no-covid patients.

CONCLUSIONS

The COVID-19 pandemic has caused major changes in daily clinical practice, especially in areas such as Emergency. This has led to a temporary reduction and changes in the flow of patients to the emergency room, with implications also for emergency surgical activities.

Long-Term Survival in Metastatic Melanoma Patients Treated with Sequential Biochemotherapy: Report of a Phase II Study

The overall survival for patients with metastatic melanoma is very poor, with a median survival of 8.5 months. In this Phase II trial, we assessed the efficacy, safety, and tolerability of a sequential biochemotherapy schedule, using dacarbazine as antiblastic agent and immunomodulant doses of interleukin-2 and interferon-alfa. Thirty-one eligible patients with metastatic melanoma received dacarbazine IV as antiblastic therapy and interluekin-2, plus interferon-alfa SC as sequential immunotherapy, for 6 months. Responding and nonprogressing patients were subsequently maintained on immunotherapy treatment for further 6 months. Twenty-nine patients had an adequate trial, and were assessable for both response and toxicities, with a median follow-up of 49 months. The overall response rate was 52 percent (3 CR and 12 PR), SD was 8 (27 percent) and PD were achieved in 6 patients (21 percent). The median survival duration of responders was 28 months, significantly longer (p < 0.001) than the 16 months of nonresponders. Therapy was well tolerated and produced a significant improvement in progressive-free survival. Further studies, thus, are recommended for larger groups of patients not only to confirm these results, but also to apply this biochemotherapy regimen as adjuvant postsurgical treatment in early stages of malignant melanoma.

Oxaliplatin, 5-fluorouracil/leucovorin and epirubicin as first-line treatment in advanced gastric carcinoma: a phase II study

The association between oxaliplatin and 5-fluorouracil (5-FU) has been extensively reported to improve prognosis of gastric cancer patients. The present study is aimed at evaluating response rate and the toxicity profile of the association with oxaliplatin, 5-FU/lecovorin and epirubicin in gastric cancer patients with locally advanced or metastatic disease. Thirty-six patients have been enrolled and 35 evaluated. The treatment schedule was oxaliplatin (100 mg m(-2)), 5-FU (400 mg m(-2)), leucovorin (40 mg m(-2)) and epirubicin (60 mg m(-2)) intravenously. administered every 3 weeks for 6 months, for a total of 185 therapy cycles . Response rate and toxicity were assessed according to the international WHO criteria. Every patient received a mean of 5.3 therapy cycles in a day-hospital setting. Sixteen of 35 patients (46%) showed an objective response, two complete response and 14 partial response. Median time to progression was 33 weeks with an overall median survival of 49 weeks. During the study, anaemia grade 3 and neutropenia grade 3 were observed in 9 and 11% of patients respectively. A grade 3 periferic sensorial neuropathy was observed in 6% of patients. No life threatening or cardiac toxicity was recorded. The regimen used showed anticancer activity against gastric carcinoma, a tolerable toxicity profile and excellent patient compliance.

Management of true splenic artery aneurysms. Two case reports and review of the literature

Few series of splenic artery aneurysms (SAA) have been reported, but today asymptomatic SAA are detected with increasing frequency. Their importance lies from their potentially fatal consequences as life-threatening hemorrhage. SAA management still remains controversial as reported in this review. Our 2 patients treated with resection of the aneurysms, both located in the middle third of the splenic artery. Some authors demonstrated that when splenic artery has been ligated (or embolized) and the patients remain anatomically splenic, they may not retain any splenic function. Laparoscopic SAA ligation repair appears to be optimal and useful for aneurysms protruding from the pancreas and it is gaining interest because clinical recovery is rapid with a poor morbidity and economic and cosmetic advantages. Transcatheter embolization too offers a temporary control in urgency to stop hemorrhage and go back at later date to make much better elective operation. Endovascular interventions as percutaneous embolization has recently gained popularity: it offers a safe alternative or adjunctive therapy to traditional surgery. We hope in the future instrumentation will likely improve so that this procedure can be done percutaneously by development of prosthetic devices in the 21th century.

Weekly gemcitabine plus Epirubicin as effective chemotherapy for advanced pancreatic cancer: a multicenter phase II study

The current role of chemotherapy in pancreatic carcinoma is limited, and progress in the treatment of this disease represents a significant challenge to medical oncology. The most promising drug under study is gemcitabine, a relatively new antimetabolite that represents an attractive candidate for combination chemotherapy because of its excellent side-effect profile and the absence of overlapping toxicities with other chemotherapeutic agents. Combined administration of gemcitabine and anthracyclines could result in the induction of DNA breaks that are not easily repaired by the cell's machinery, thus enhancing the apoptotic signals triggered by these lesions. Forty-four patients with locally advanced and/or metastatic pancreatic adenocarcinoma were enrolled in this multicenter study. Patients received Epirubicin 20 mg m(-2) for 3 weeks followed by 1 week of rest (1 cycle) and gemcitabine 1000 mg m(-2) after Epirubicin on the same day. All were assessable for toxicity and response, 11 patients responded to treatment with one complete response and 10 partial responses, for an overall response rate of 25%. Median survival was 10.9 months (range, 2-26 months). Therapy was well tolerated, with a low incidence of haematologic grade >2 toxicity. A total of 12 of 27 (44.4%) eligible patients attained a clinical benefit response. Our findings suggest that the gemcitabine-epirubicin schedule is active and well tolerated in patients with advanced pancreatic cancer.

Raltitrexed plus oxaliplatin as first-line chemotherapy in metastatic colorectal carcinoma: a multicentric phase II trial

For advanced colorectal carcinoma, two new drugs, raltitrexed (TOM) and oxaliplatin (L-OHP), have recently shown interesting results. Preclinical and clinical studies suggest that this combination, because of its favorable toxicity profile, high response rate and convenient schedule of administration, can be administered successfully in this disease. In our phase II study, 37 non pre-treated patients with metastatic colorectal carcinoma were treated with TOM (3 mg/m(2)) and L-OHP (130 mg/m(2)) every 3 weeks. In total, 222 cycles were administered; all patients received at least 2 cycles (median 6, range 2-8). There were two complete and 14 partial responses for an overall response rate of 43% (95% CI 27-69%). The median time to response was 2.5 months (range 2-4) and the median duration was 10.3 months (range 5-18). Twelve of the 23 (52%) patients with symptomatic colorectal cancer were classified as clinical benefit responders for at least 4 weeks during the study period. Treatment was well tolerated, and both acute, essentially hematologic, and cumulative hepatic and neurologic toxicities were manageable and reversible. Response rate and toxic effects observed during this study warrant additional studies comparing this TOM-L-OHP regimen with CPT-11 and/or capacitebine-containing regimens in metastatic colorectal carcinoma.

Improved survival in small pancreatic cancer

BACKGROUND

Although the incidence of pancreatic cancer is relatively low compared with other tumors (2.4%), the death rate is high. Tumor detection and treatment at an early stage is necessary to improve the poor prognosis of patients, as is demonstrated by some reports showing a 5-year survival rate varying between 19 and 41% for patients undergoing radical pancreatectomy with the highest survival in patients with small tumors.

METHODS

In our study we retrospectively reviewed the histologic and demographic data of 596 patients who were admitted to the surgical units of the Careggi Hospital (University of Florence-AOC of Florence) between 1988 and 1994 with the incoming diagnosis of pancreatic cancer.

RESULTS

Results are reported as the mean +/- standard deviation. The postoperative survival rate was calculated by the Kaplan-Meier method and statistical analysis was performed by the log rank test (significance p < 0.05). 247 patients had surgery, 110 with a curative intent. Postoperative mortality was 5.45%. The crude 5-year survival rate for patients who underwent curative surgery was 16.36% (18 patients), but for patients with small lesions confined to the pancreas (T1N0M0, 29 patients) this was even 31.03% (9 patients; p < 0.01, chi2 test).

CONCLUSIONS

Our results indicate that it seems reasonable to consider these cancers as 'small', with survival reported in literature from 35 to 41%, so they probably represent the only curable condition at the present time.

[Genetic anomalies of pancreatic carcinoma and clinical applications]

Pancreatic cancer is a dismal disease. The 5-years overall survival ranges from 1% to 5%. Surgery is the only curative treatment available. Survival of selected patients with small lesion (< 2 cm) confined to the pancreas is improved to 19-41%. Presently the major effort is on studies of the cancer development phenomena to improve detection of patients with early lesions. The analysis of oncogene and tumor-suppressor gene activation may enable us to better define and cure this disease. Molecular genetic new tecnquiques performed on pancreatic juice, duodenal juice and stool, probably are the most promising new approach for early diagnosis of pancreatic cancer. This could be the right path to diagnose pancreatic malignant lesions at a curable stage, and to discriminate patients with a more favourable prognosis candidates to be submitted to adjuvant therapy with a curative intent, and also to discriminate real pancreatic cancer from patients with chronic pancreatitis.

Primary leiomyosarcoma of the pancreas: a case report and review of literature

Primary leiomyosarcoma of the pancreas is a rare tumor for which only 21 reports appear in the world literature. We describe an additional case of pancreatic leiomyosarcoma in a 76-year-old man, who complained of persistent high fever. Histologic examination revealed a pleomorphic spindle cell tumor. Reactivity for muscle-specific actin, alpha-smooth muscle actin, and basement membrane components, along with negative staining for epithelial and neural markers, were consistent with a smooth muscle sarcoma. The patient died of disease 1 year after complete surgical excision. This report highlights the need to use a complete antibody panel in order to accurately immunophenotype pleomorphic malignant tumors of the pancreas. A review of the cases compiled in the literature indicates that pancreatic leiomyosarcoma, like its counterpart arising in deep soft tissues, is an aggressive neoplasm characterized by short survival and a high rate of metastases.

[An angiogenesis study of Dukes' B colonic tumors]

PURPOSE

To evaluate the angiogenesis in Dukes' B colon cancer.

PATIENTS AND METHODS

In 60 patients (age, 39-75 years), the microvessel density and the relationship between the angiogenesis and other histologic features were retrospectively evaluated. In an ongoing prospective study, 25 patients have been enrolled to determine the possible therapeutic implications of VEGF quantitative analysis.

RESULTS

The retrospective portion of this study confirms the prognostic value of the angiogenesis in terms of recurrences and survival. At present, no conclusions can be drawn from the prospective portion of the study.

Results of leucovorin and doxifluridine oral regimen in the treatment of metastatic colorectal cancer

We conducted a multicentric phase II study on advanced colorectal cancer to determine the efficacy and toxicity of oral treatment with leucovorin (LV) plus doxifluridine (5'DFUR), a novel fluoropyrimidine derivative with proven antitumor activity in different experimental models. Thirty-six outpatients with measurable disease entered the trial and received orally LV 20 mg in the morning and in the afternoon, and 2 h later 5'-DFUR 500 mg/m2 every 2 days for 3 months. Thirty-four evaluable patients underwent a total of 408 weeks of treatment. The response rate was 35%, with two complete remissions and 10 partial responses. The median survival of patients who responded to treatment (responders) was 17.1 months (range 4-32), which was significantly longer (p<0.001) than the 6.5 months (range 2-11) of the patients who did not respond (non-responders). Therefore, after 4-8 weeks of treatment, 14 patients (41%) had an improvement in their performance status and/or stabilization of pain. General toxicity was usually mild, myelo and gastrointestinal toxicity were moderate, and there was no evidence of relevant neurological toxicity. These results show that a home therapy with oral LV-5'DFUR is a safe and effective treatment regimen for metastatic colorectal carcinoma.

[On the subject of pancreatic ductal carcinoma]

Pancreatic cancer is a dismal disease. The 5-year overall survival ranges from 1% to 5%. Surgery is the only curative treatment available for this cancer, but it is indicated only in selected patients with a less than 4 cm tumor. In these patients, survival rate is about 30%. We have considered several aspects: the very difficult early diagnosis, the correct diagnostic flow chart, actual surgical procedures and new trends in biologic and genetic research. It is likely that better results can be achieved by defining an "early pancreatic cancer" and establishing how to detect it. This could be the wrigth one way is to significantly improve the survival of these patients.

Analysis of clinicopathologic prognostic features in patients with gastric adenocarcinoma

BACKGROUND

We evaluated the influence of several clinicopathologic variables on 5-year actuarial survival rate after curative resection of gastric adenocarcinoma.

METHODS

Clinical characteristics were retrieved from the records of all patients who underwent gastric resection for curative intent between 1965 and 1986 at The University of Chicago Medical Center, and follow-up was obtained from our tumor registry. Pathologic characteristics were determined from a detailed review of all available histopathologic slides.

RESULTS

One hundred seventy-eight patients underwent a curative resection during the study period at our institution. Overall 5-year actuarial survival rate was 29%. The relationship between clinicopathologic variables and 5-year survival rate was evaluated by Kaplan-Meier survival curve construction and chi-squared analysis. Lymphatic and/or capillary microinvasion (absent vs present, p < 0.001), tumor location (antrum and body vs gastroesophageal junction, p = 0.05), local extent of disease (limited to the gastric wall versus involving adjacent organs, p = 0.003), stage (absence versus presence of lymph node metastases, p < 0.001), Lauren type (intestinal versus diffuse, p < 0.01), and Ming type (expanding versus infiltrative, p < 0.02) significantly influenced survival. When a multivariate analysis with logistic regression of 5-year survival was performed, lymphatic and/or capillary microinvasion emerged as the only statistically significant, independent prognostic factor associated with long-term survival (p = 0.039). If microinvasion was omitted from the analysis, lymph node metastases (p < 0.05) and the extension to adjacent organs (p < 0.04) became the only statistically significant variables. Multiple correlation analyses suggested that microinvasion is an early histopathologic finding that correlates with a more aggressive natural history.

CONCLUSIONS

Lymphatic and/or capillary microinvasion is a more powerful predictor of 5-year survival than lymph node metastases or tumor extension to adjacent organs. Correlation among clinicopathologic variables suggests that microinvasion may represent an early finding, serving as a potential marker for a biologically more aggressive tumor.

Nitric oxide synthase immunoreactivity in the human ileocecal region

The nitric oxide (NO) producing neurons in the human ileocecal region (pre-junctional ileum, ileocecal and cecocolonic junctions, cecum and post-junctional colon) have been evaluated by immunocytochemistry. The percentage of NO synthase-positive neurons was higher at the myenteric plexus than at the submucous plexus, independently of the levels examined. The inner portion of the circular muscle layer, except at the ileal level, was devoid of immunoreactive nerve fibers. Data obtained suggest that neuronal-released NO at the ileocecal region has a greater role in the relaxation of the muscle coat, except for the inner circular muscle layer, than in the regulation of blood flow, absorptive and secretory processes.

Distribution of VIP-immunoreactive nerve cells and fibers in the human ileocecal region

VIP-containing nerve cells and fibers in the human ileocecal region (pre-junctional ileum, ileocecal and cecocolonic junctions, post-junctional cecum and colon) have been evaluated by immunocytochemistry. A high density of VIP-positive neurons and nerve fibers was found in all layers of the ileum. At all colonic levels examined and at both junctions, the percentage of VIP-containing cells was higher in the submucous plexus than in the myenteric plexus. At both junctions, the muscle wall was devoid of, and the myenteric plexus extremely poor in VIP-positive nerve fibers and cells. These data suggest that motility of these junctions is not--or only to a minor extent--regulated in man by VIP-containing nerves, at variance with other gut sphincteric areas.

Epidoxorubicin and high dose leucovorin plus 5-fluorouracil in advanced gastric cancer: a phase II study

We conducted a multicentric phase II study on advanced gastric cancer to determine the efficacy and toxicity of treatment with epidoxorubicin (EPI) plus high doses of leucovorin (LV) and 5-fluorouracil (5-FU). Thirty-seven patients with measurable disease were enrolled into the trial and treated with EPI 75 mg/m2 on day 1 and LV 200 mg/m2 plus 5-FU 450 mg/m2 from day 1 to 3, the cycle being repeated every 3-4 weeks from a median of five cycles per patients. The response rate was 49% in 35 evaluable patients, with two complete remissions and 15 partial responses. Median response duration was 12.4 months; median survival for responding patients was 17.3 months, which was significantly longer than 8.7 months for non-responding patients. General toxicity was usually mild, myelotoxicity was moderate and there was no evidence of cardiac toxicity. These results show that EPI-LV-5-FU is an effective regimen for advanced gastric carcinoma. The efficacy of this combination should now be tested as an adjuvant therapy in resectable gastric cancer.

Morphological evidence for a cecocolonic junction in man and functional implications

The region above, below and in front of the ileocecal valve opening has been studied in man using both light and electron microscopy. A cecocolonic junction, comprising the colonic basal portion of the ileocecal valve, could be demonstrated in man, due to the specific anatomy of the inner portion of the circular muscle. This muscle was arranged in anastomosing cords, richly innervated and enveloped by elastic fibers. Its smooth muscle cells were characterized by extremely wide sarcoplasmic cisternae and cell-to-cell junctions, numerous caveolae and large amounts of glycogen. Interstitial cells were rarely found. This junction might be considered responsible for (1) ileal flow accommodation, (2) colonic active movements and (3) ileocecal valve closing and opening.

GABAB receptor-mediated mechanisms in human intestine in vitro

The spontaneous motility of longitudinal muscle of human jejunum was recorded and the effect of gamma-aminobutyric acid-ergic (GABAergic) drugs was tested. GABA and (-)-baclofen (10(-6)-10(-4) M) dose dependently reduced the amplitude and frequency of the spontaneous contractions; muscimol and 3-aminopropanesulfonic acid (3 x 10(-5) M) were ineffective. The effect of 3 x 10(-5) M GABA was reduced by 3 x 10(-3) M 5-aminovaleric acid but not by 3 x 10(-5) M picrotoxin. The dose-response curve for GABA was shifted to the right by 3 x 10(-3) M 3-aminopropanesulfonic acid. Tetrodotoxin 3 x 10(-7) M prevented the GABAergic action, whereas various receptor antagonists tested did not affect it. GABAergic drugs did not influence the spontaneous motility of either circular or longitudinal muscles of human colon. It is suggested that GABAB receptor activation induces the inhibition of human jejunum longitudinal muscle motility by a neurogenic mechanism. The possible involvement of postganglionic cholinergic neurons is to be evaluated by other techniques.

Usefulness of colonic motility study in identifying patients at risk for complicated diverticular disease

Colonic motility study was performed on a total of 145 patients. Of these, 55 were patients with symptomatic complicated diverticular disease, 30 had symptomatic uncomplicated diverticular disease, 30 had asymptomatic diverticular disease, and 30 were controls. The pressure sensors were positioned in the descending and the true sigmoid colon. Colonic motility index was significantly higher in symptomatic rather than in asymptomatic diverticular disease in the resting (P less than 0.001) and postprandial (P less than 0.001) states. This confirmed the association between symptomatic diverticular disease and high intraluminal pressure. The patients of the subgroup--complicated diverticular disease--were relatively young (mean age: 51.1 +/- 2.02 years) and had a short history of abdominal pain (18-36 months) and a short segment of colon with diverticula (cm 7.25 +/- 1.31). Our observations suggest that patients showing these indicators are at risk for major complication.

Neuromuscular structures specific to the submucosal border of the human colonic circular muscle layer

The circular muscle layer of the human caecum and ascending colon is clearly subdivided into two portions: an outer one which includes the bulk of the circular muscle layer, and an inner one made up of only six to eight rows of cells. In the right transverse colon no demarcation can be observed, but a difference exists between the innermost and the outermost cells, since those of the two innermost rows possess some peculiarities with regard to the sarcoplasmic reticulum, glycogen particles, caveolae, and intercellular junctions. In the left part of the colon, the circular muscle layer is also divided into two portions. In fact, the innermost smooth muscle cells still possess peculiar morphologies, progressively increase in number, and become separate from each other making up a superficial muscle network. A fibrous lamella, along and inside which a ganglionated nerve plexus runs, is strictly apposed to the submucosal border of the circular muscle layer of the entire colonic length. A second nerve plexus runs between the two portions of the circular muscle layer. Both these plexuses are accompanied by interstitial cells of Cajal in the right colon only. The peculiar organization of the entire submucosal border of the human colonic circular muscle layer distinguishes it from other parts of the gut and probably represents a structural basis for control of human colonic motility. The presence of putative pacemaker cells (interstitial cells and peculiar smooth muscle cells) indicates that the inner border of human colonic circular muscle layer possesses pacemaking activities. Moreover, the interstitial cell--smooth muscle cell ratio differs depending on the colonic level; two main regions can be identified: the right and the left colon. Consequently, we might expect regional variation in pacemaking.

[Diverticular disease of the colon. Concepts to be reviewed for a rational therapeutic approach]

Indicators of a risk group for complicated diverticular disease have been suggested. They are: a) Age 50 years, 2) short history of left lower quadrant abdominal pain, 3) short segment of colon with diverticula, 4) elevated motility index.

Smooth muscle cells, interstitial cells of Cajal and myenteric plexus interrelationships in the human colon

The plane between longitudinal and circular muscle of human colon, as revealed on examination with light and electron microscopes, has no clear-cut border. Some groups of smooth muscle cells, obliquely oriented and with features similar to both circular and longitudinal ones--the connecting muscle bundles--run from one muscle layer to another. Other groups of smooth muscle cells, possessing their own specific ultrastructural features--the myenteric muscle sheaths--, make up envelopes of variable thickness around some myenteric ganglia and nerve strands, partially or completely embedding them in one or other muscle layer. Non-neuronal, non-muscular cells (interstitial cells of Cajal, covering cells, fibroblast-like and macrophage-like cells) complicate the texture of the myenteric muscle sheaths, creating an intricate, interconnected cellular network inside them, widespread among nerve bundles and smooth muscle cells; however, only interstitial cells have cell-to-cell junctions also with the smooth muscle cells and nerve endings. These data document the existence in this colonic area of two different types of muscle cell arrangements, one of which, the myenteric muscle sheath, only contains putative pacemaker cells.

[Esophageal motor abnormalities, gastroesophageal reflux and duodenogastric reflux in patients with Raynaud's disease]

Twenty-four patients with Raynaud's phenomenon, without ARA criteria for classification, were examined, after clinical history, by means of esophageal manometry, combined gastric and esophageal pH-monitoring, endoscopy. The results showed in these patients a high incidence of esophageal motor abnormalities (66.6%), of gastroesophageal reflux (50%), and of duodenogastric reflux (45.8%).

An ultrastructural study of the interstitial cells of Cajal of the human stomach

The interstitial cells of Cajal of the human stomach were studied at the electron microscope. These cells have an exceptionally elongated shape and several lateral branches. Their cytoplasm characteristically possesses cisternae of smooth endoplasmic reticulum and filaments. A capsular-like structure surrounds them and joins them to each other and to the neighbouring nerve endings and smooth muscle cells, and so they all make up anatomical units. Elastic fibres also make bridges between these cells and between smooth muscle cells and nerve endings. Despite these common characteristics, differences in cell number, distribution in respect of the muscle bundles and some cytoplasmic features have been found, depending on where these cells are located. In fact, there are few interstitial cells in the fundus, poor in filaments and branches, and only located inside the circular muscle layer. In the corpus and antrum they are many, rich in filaments and with their numerous branches make interconnected networks, one inside the circular muscle layer, another apposed to its myenteric surface and, in the antrum, a third one apposed to its submucosal surface, which accompany analogous nerve networks. Substantial differences in the contacts between the interstitial cells and the smooth muscle cells and nerve endings have not been found. For their ultrastructural characteristics a smooth muscle nature has been suggested for these cells. A correlation has also been attempted between the electrical and mechanical activities performed by the different gastric areas and the interstitial cell structure and arrangement.

An ultrastructural study of the smooth muscle cells and nerve endings of the human stomach

The circular muscle layer of the human stomach was studied with the electron microscope. The smooth muscle cells differ structurally according to their location. In fact, the circular muscle layer of the fundus is made up of large, irregularly shaped smooth muscle cells, with long, thick, dense bands, and immersed in an abundant, elastic supporting connective tissue. In the circular muscle layer of the corpus (the two curvatures and the corpus between), those located in the outermost zone are identical to that commonly described in the alimentary tract, but are gradually substituted, first by larger irregularly shaped cells, and then, towards the innermost area, by flattened cells richer in sarcoplasmic reticulum, with thick and continuous dense bands on their submucosal surface. The smooth muscle cells of the antrum are all identical to the outermost located corporal ones. The gap junctions are absent in the fundus and in the innermost area of the corporal circular muscle layer, are present in the other areas, particularly frequent in the antrum and in the outermost area of the greater curvature. The number of the nerve endings is similar in the fundus, greater curvature and antrum, while it is two-three times more in the other parts of the corpus. They are located at the periphery of the muscle bundles in the fundus, antrum and greater curvature, sparsely scattered among the smooth muscle cells in the other areas of the corpus and contain small agranular and large granular synaptic vesicles, often mixed in the same axon. These nerve endings lie distant from the smooth muscle cells in the fundus, antrum and greater curvature and directly contact the smooth muscle cells in the other parts of the corpus.

Short-term effects of bile diversion on postgastrectomy gastric histology

Twelve partially gastrectomized subjects who have consecutively undergone total biliary diversion for severe bilious vomiting were studied before and after operation in order to assess the effects of surgery on gastric histology and enterogastric reflux. Before and six months after operation, the following protocol was performed: (1) blood examinations including serum basal gastrin; (2) endoscopy with multiple gastric biopsies; and (3) quantitation of bile acids in the gastric aspirate. Of the preoperative symptoms, bilious vomiting and heartburn completely disappeared postoperatively in all the subjects. Fasting bile reflux was significantly reduced (bile reflux was annulled in six and considerably lowered in the remaining six subjects), and erythema of the gastric mucosa completely disappeared in all the subjects after diversion. Among histological findings, while a significant regression of foveolar hyperplasia was found both in the perianastomotic area and in the body of gastric remnant, none of the other aspects identifiable in postgastrectomy gastric mucosa (chronic gastritis changes included) were affected by diversion. These results show that biliary diversion is effective in correcting reflux, bilious vomiting, erythema, and foveolar hyperplasia of the gastric mucosa and confirm the suggested relationship between bile reflux and gastric foveolar hyperplasia.