New vascular system in reptiles: anatomy and postural hemodynamics of the vertebral venous plexus in snakes.

Using corrosion casting, we demonstrate and describe a new vascular system--the vertebral venous plexus--in eight snake species representing three families. The plexus consists of a network of spinal veins coursing within and around the vertebral column and was previously documented only in mammals. The spinal veins of snakes originate anteriorly from the posterior cerebral veins and form a lozenge-shaped plexus that extends to the tip of the tail. Numerous anastomoses connect the plexus with the caval and portal veins along the length of the vertebral column. We also reveal a posture-induced differential flow between the plexus and the jugular veins in two snake species with arboreal proclivities. When these snakes are horizontal, the jugulars are observed fluoroscopically to be the primary route for cephalic drainage and the plexus is inactive. However, head-up tilting induces partial jugular collapse and shunting of cephalic efflux into the plexus. This postural discrepancy is caused by structural differences in the two venous systems. The compliant jugular veins are incapable of sustaining the negative intraluminal pressures induced by upright posture. The plexus, however, with the structural support of the surrounding bone, remains patent and provides a low-pressure route for venous return. Interactions with the cerebrospinal fluid both allow and enhance the role of the plexus, driving perfusion and compensating for a posture-induced drop in arterial pressure. The vertebral venous plexus is thus an important and overlooked element in the maintenance of cerebral blood supply in climbing snakes and other upright animals.

Resting and maximal heart rates in ectothermic vertebrates.

Resting and maximal heart rates (HR) in ectothermic vertebrates are generally lower than those in endotherms and vary by more than an order of magnitude interspecifically. Variation of HR transcends phylogeny and is influenced by numerous factors including temperature, activity, gas exchange, intracardiac shunts, pH, posture, and reflexogenic regulation of blood pressure. The characteristic resting HR is rarely the intrinsic rate of the pacemaker, which is primarily modulated by cholinergic inhibition and adrenergic excitation in most species. Neuropeptides also appear to be involved in cardiac regulation, although their role is not well understood. The principal determinants of resting HR include temperature, metabolic rate and hemodynamic requirements. Maximal HRs generally do not exceed 120 b min-1, but notable exceptions include the heterothermic tuna and small reptiles having HRs in excess of 300 b min-1 at higher body temperatures. Temperature affects the intrinsic pacemaker rate as well as the relative influence of adrenergic and cholinergic modulation. It also influences the evolved capability to increase HR, with maximal cardiac responses matched to preferred body temperatures in some species. Additional factors either facilitate or limit the maximal level of HR, including: (1) characteristics of the pacemaker potential; (2) development of sarcoplasmic reticulum as a calcium store in excitation-contraction coupling; (3) low-resistance coupling of myocardial cells; (4) limitations of force development imposed by rate changes; (5) efficacy of sympathetic modulation; and (6) development of coronary circulation to enhance oxygen delivery to myocardium. In evolutionary terms, both hemodynamic and oxygen requirements appear to have been key selection pressures for rapid cardiac rates.

Contribution of the vertebral artery to cerebral circulation in the rat snake Elaphe obsoleta.

Blood supplying the brain in vertebrates is carried primarily by the carotid vasculature. In most mammals, cerebral blood flow is supplemented by the vertebral arteries, which anastomose with the carotids at the base of the brain. In other tetrapods, cerebral blood is generally believed to be supplied exclusively by the carotid vasculature, and the vertebral arteries are usually described as disappearing into the dorsal musculature between the heart and head. There have been several reports of a vertebral artery connection with the cephalic vasculature in snakes. We measured regional blood flows using fluorescently labeled microspheres and demonstrated that the vertebral artery contributes a small but significant fraction of cerebral blood flow (approximately 13% of total) in the rat snake Elaphe obsoleta. Vascular casts of the anterior vessels revealed that the vertebral artery connection is indirect, through multiple anastomoses with the inferior spinal artery, which connects with the carotid vasculature near the base of the skull. Using digital subtraction angiography, fluoroscopy, and direct observations of flow in isolated vessels, we confirmed that blood in the inferior spinal artery flows craniad from a point anterior to the vertebral artery connections. Such collateral blood supply could potentially contribute to the maintenance of cerebral circulation during circumstances when craniad blood flow is compromised, e.g., during the gravitational stress of climbing.

[Surgical therapy of non-Hodgkin lymphoma of the stomach]. / Chirurgische Therapie der Non-Hodgkin-Lymphome des Magens.

The value of surgical treatment is less well defined in gastric lymphoma than in gastric carcinoma. Therefore, we analysed the outcome of 245 patients with gastric malignancies, which were treated from 1.1.1988 to 31.12.1995 in the Department of Surgery/Charité. Twenty patients suffered from a non-Hodgkin-lymphoma and only 14 (8%) were diagnosed correctly by preoperative endoscopical biopsy. Seven patients with limited lymphoma underwent primary surgical therapy (total gastrectomy n = 4, subtotal gastrectomy n = 3). Seven patients with disseminated lymphoma (stage EIII-IV) were treated by neoadjuvant chemotherapy (CHOP), that was followed by gastrectomy (R0: n = 2, R1: n = 4) or explorative laparotomy (n = 1). Five patients (25%) were diagnosed as undifferentiated carcinoma and underwent total gastrectomy with D2-lymphadenectomy (R0: n = 5). One patient (5%) underwent emergency surgery due to gastric perforation. One patient (5%) died in hospital due to insufficient anastomosis after total gastrectomy and preoperative chemotherapy. Nine patients with high-grade malignant lymphomas received postoperative chemotherapy. The 1-, 2,- and 5-year-survival-rate was 95%, 89% and 44%. Although, many questions are still open, surgical therapy remains an important option in the multimodal treatment of gastric lymphoma.

Quality of life after surgical treatment of gastric carcinoma.

OBJECTIVE: To see if there was a correlation between self-assessment and external evaluation of quality of life (QL) after resection of gastric carcinoma, a correlation between overall QL and different components, and the impact of social and medical factors on QL. DESIGN: Prospective study. SETTING: University hospital, Germany. SUBJECTS: 71 patients assessed once 12 months after R0-resection of gastric carcinoma and 35 patients assessed regularly, starting postoperatively. INTERVENTIONS: QL was assessed by the patients using the European Organisation for Research and Treatment of Cancer (EORTC) core QL questionnaire (QLQ-C36) and by a psychologist using the Spitzer Index. MAIN OUTCOME MEASURES: Correlations between self-assessment and external assessment, between overall scores and single items of QL, and between social and medical factors and QL, as well as changes in QL-scores during postoperative follow-up. RESULTS: Self-assessment and external evaluation of global QL showed a significant but not particularly close correlation (r = 0.40) and QL was evaluated as better by the external observer using the Spitzer Index. All physical, emotional, and social components of the QLQ-C36 correlated significantly with patients overall evaluation of QL. Postoperative QL was affected mainly by somatic complaints and physical limitations. Of several factors analysed, tumour recurrence was the decisive factor in deciding patients' QL. Compared with the preoperative assessment, QL had deteriorated on discharge from hospital but was restored during the following six months in patients who remained disease-free. CONCLUSION: Compared with the Spitzer Index the QLQ-C36 differentiates the QL of patients with gastric cancer better and disease-specific complaints are included.

[Immune stimulation with G-CSF (Neupogen) in septic patients with immune paralysis]. / Immunstimulation durch G-CSF (Neupogen) bei septischen Patienten mit Immunparalyse.

Ten patients with sepsis (HLA-DR+ monocytes < 30%) were treated with G-CSF (300 mg Filgrastin, Neupogen 30, Amgen). All patients showed a rise in HLA-DR+ monocytes during therapy. In six patients the high level of HLA-DR+ monocytes persisted after therapy; these patients survived. In the other four patients the number of HLA-DR+ monocytes declined after application of G-CSF, and the patients died of multiorgan failure. Some patients with sepsis might profit from immunestimulating therapy with G-CSF, but further studies are needed to prove whether or not this is true.

[Does the pouch modify food transit after gastrectomy?]. / Beeinflusst der Pouch den Nahrungstransit nach Gastrektomie?

A prospective, randomized study of patients with gastric cancer was performed to examine whether or not the jejunal pouch interposition between esophagus and duodenum after gastrectomy is of importance. At fixed postoperative times, standardized scintigraphic measurements were performed; the quality of life was evaluated by the EORTC quality of life questionnaire. Our findings suggest that interposition of a jejunal pouch reservoir between esophagus and duodenum may be due to a prolonged transit time and a better quality of life.

[A rare stomach tumor--Hodgkin's lymphoma of the stomach]. / Ein seltener Magentumor--das Hodgkin-Lymphom des Magens.

Gastric involvement of Hodgkin's disease is very rare and preoperative diagnosis is difficult. We report the case of a 50-year-old woman, who had an ulcerating tumor of the antrum, which was revealed as carcinoma by endoscopic biopsy. A gastrectomy with D2-lymph node dissection was performed. In the pathological specimen Hodgkin's disease was diagnosed because of microscopic detection of typical binucleated Reed-Sternberg cells. Although the patient refused additive chemotherapy, she is still disease-free after 12 months of follow-up.