Electrical activity and ultrastructure of bovine mesenteric lymphatics.

Membrane action potentials of bovine mesenteric lymphatics were recored simultaneously with isometric contractions by use of the sucrose gap method. The action potentials always had one-to-one correspondence to the contraction waves. From the effects of tetrodotoxin, manganese, cal-calcium-free environment, and barium chloride on the spontaneous contractions, it was suggested that calcium current may probably play a major role in producing spike discharge in the smooth muscles. Blood capillaries were found within the smooth muscle layers as well as in the adventitia.     

Structural and functional studies of leptins from hibernating and non-hibernating bats

Leptin, a 16-kDa hormone produced by mature adipocytes, has been shown to regulate the hibernation of mammals. In this study, the leptin gene sequences of both hibernating (Rhinolophus ferrumequinum) and non-hibernating (Rousettus leschenaultii) bats were determined, and the leptin proteins from these two different species of bats were expressed in Escherichia coli for the first time. Results showed that the amino acid sequence of the leptin protein from hibernating bats had a lower degree of identity than that from non-hibernating bats to those of several non-hibernating mammals. The leptin protein of hibernating bats had a stronger growth inhibitory effect on 3T3-L1 cells than that of non-hibernating bats. Structural modeling revealed that the structures of the receptor binding site III, which is critical for signal transduction, of the two bat leptins were very different. Similar to the human leptin, the leptin protein of non-hibernating bats was predicted to have a random loop, whereas that of hibernating bats had a helical structure in this region. This observation provided a clue as to the differential effects of the two different leptins on 3T3-L1 cells.     

Helminth parasites in some Spanish bats

Nineteen bats of the species Rhinolophus ferrumequinum, R. hipposideros, Myotis myotis, M. nattereri, Pipistrellus pipistrellus, Barbastella barbastellus, Eptesicus serotinus and Plecotus auritus captured in N. W. Spain in 1983-85 were found to contain the following helminth parasites: Mesotretes peregrinus (found in 4 host species and making up 31% of all helminths); Plagiorchis vespertilionis (10.5%, in 2 host species); Strongylacantha glycirrhiza, Molinostrongylus alatus, Molineidae gen. sp., Capillariidae gen. sp., Hymenolepis acuta, Cestoda gen. sp. and Trematoda gen. sp. I and II (5.2% in 1 host species).     

Cardioprotection in stunned and hibernating myocardium

Although myocardial ischemia was once thought to result in irreversible cellular damage, it is now demonstrated that in cardiac tissue, submitted to the stress of oxygen and substrate deprivation, endogenous mechanisms of cell survival may be activated. These molecular mechanisms result in physiological conditions of adaptation to ischemia, known as myocardial stunning and hibernation. These conditions result from a switch in gene and protein expression, which sustains cardiac cell survival in a context of oxygen deprivation and during the stress of reperfusion. The pattern of cell survival elicited by ischemia in myocardial stunning or hibernation results in the activation of cytoprotective mechanisms that will protect the heart against further ischemic damage, a condition referred to as ischemic preconditioning. The basic mechanisms underlying stunning and hibernation are still a matter of intense research, which includes the discovery and characterization of novel survival genes not described in the heart before, or the unraveling of new cellular processes, such as autophagy. Understanding how the molecular adaptation of the cardiac myocyte during stress sustains its survival in these conditions therefore might help defining novel mechanisms of endogenous myocardial salvage, in order to expand the conditions of maintained cellular viability and functional salvage of the ischemic myocardium.     

In patients with type 1 diabetes simultaneous pancreas and kidney transplantation preserves long-term kidney graft ultrastructure and function better than transplantation of kidney alone

Aims/hypothesis

In patients with type 1 diabetes and end-stage renal disease (ESRD) we aimed to determine whether long-term normoglycaemia, as achieved by successful simultaneous pancreas and kidney (SPK) transplantation, would preserve kidney graft structure and function better than live donor kidney (LDK) transplantation alone.

Methods

Estimated GFR (eGFR) was calculated in SPK (n?=?25) and LDK (n?=?17) recipients in a stable phase 3 months after transplantation and annually during follow-up. Kidney graft biopsies were obtained at follow-up for measurement of glomerular volume (light microscopy), glomerular basement membrane (GBM) and podocyte foot process widths and mesangial volume fraction (electron microscopy).

Results

SPK and LDK recipients were similar in age and diabetes duration at engraftment. Donor age was higher in the LDK group. Median follow-up time was 10.1 years. Mean HbA_1c levels during follow-up were 5.5?±?0.4% (37?±?5 mmol/mol) and 8.3?±?1.5% (68?±?16 mmol/mol) in the SPK and LDK group, respectively (p?p?=?0.008) and increased mesangial volume fraction (median 0.23 [range 0.13–0.59] vs 0.16 [0.10–0.41]; p?=?0.007) at follow-up. Absolute eGFR change from baseline was ?11?±?21 and ?23?±?15 ml min^?1 1.73 m^?2 (p?=?0.060), whereas eGFR slope was ?1.1 (95% CI ?1.7, ?0.5) and ?2.6 (95% CI ?3.1, ?2.1)?ml min^?1 1.73 m^?2 per year in the SPK and LDK group, respectively (p?=?0.001).

Conclusions/interpretation

In patients with type 1 diabetes and long-term normoglycaemia after successful SPK transplantation, kidney graft ultrastructure and function were better preserved compared with LDK transplantation alone.     

Comparison of isoenzymes of some species of the subgenus schizotrypanum from bats by isoelectrofocusing

Culture forms of bat-trypanosomes of the species T. dionisii, T. vespertilionis and T.c. marinkellei were compared isoenzymatically by isoelectrofocusing. The enzymes tested were: nonspecific esterase (NSE, E.C.3.1.1.), phosphoglucomutase (PGM, E.C. 2.7.5.1), glucose-6-phosphate dehydrogenase (G-6-PD, E.C. 1.1.1.49), glucosephosphate isomerase (GPI, E.C. 5.3.1.9), malate dehydrogenase (MDH, E.C. 1.1.1.37), alcohol dehydrogenase (NADP+) (ADH, E.C. 1.1.1.2). Their enzyme types were related to those of T. cruzi. The comparison of enzyme patterns of the six enzymes has shown that each species was characterized by species-specific enzyme profiles. Among the stocks of the European species, T. dionisii, and T. vespertilionis, variations of the enzyme patterns of PGM, G-6-PD and GPI suggesting that the final status of this subspecies is probably not yet established. In relation to T. cruzi it has been found that T. dionisii showed identical enzyme profiles with group II of T. cruzi. For T. vespertilionis no enzyme types identical with T. cruzi were detectable. T.c. marinkellei showed only identical enzyme patterns to T. cruzi-group I by the enzymes NSE and GPI.     

An ultrastructural study of the transport pathways across arcuate,interlobar, hilar,and capsular lymphatics in the dog kidney

The ultrastructurally visible transport pathways across arcuate, interlobar, hilar, and capsular lymphatics were studied in canine kidneys with unimpeded lymph and urine flow. The four types of vessels were lined by a nonfenestrated endothelium resting on a discontinuous basal lamina and contained valves. Stereological techniques were applied to determine the volume and numerical densities for cytoplasmic vesicles (80–90 nm in diameter). Values for those parameters increased sequentially in the direction of lymph flow from the kidney. Thus, vesicular volume density rose from 6% of endothelial cytoplasm in arcuate lymphatics to 14% in hilar vessels, and the numerical density increased from 11 vesicles/μm³ to 33 vesicles/μm³. Most of the vesicles lay apparently free within the cytoplasm, the remainder were evenly dispersed along the luminal and abluminal cell borders. Three varieties of interendothelial cell contacts were present: end-to-end, overlap, and interdigitation. Specialized junctional complexes associated with these contacts were either fasciae occludentes or fasciae adhaerentes, although in many instances neither were present. In general, arcuate and interlobar lymphatics had more cell contacts which lacked junctional specializations than did hilar and capsular lymphatic vessels. Only one example out of 676 cell contacts could be classified as “open” (greater than 30-nm gap along the entire contact length). It was concluded that (1) the four types of lymphatic vessels in the present study have ultrastructural features of lymph-forming (as opposed to simple collecting) vessels, (2) the ultrastructurally visible transport pathways in the four types of vessels studied are through “normal” (5- 30-nm wide) intercellular channels and via cytoplasmic vesicles, (3) arcuate and interlobar lymphatics have a structure which is consistent with the formation of lymph from medullary interstitial fluid, (4) hilar and capsular lymphatics may have a role in extrarenal lymph formation, and (5) “open” contacts are not involved normally in translymphatic transport in the kidney.     

饮茶型氟中毒大鼠骨组织及肾脏超微结构观察

目的 从亚细胞水平观察砖茶氟对骨组织及肾脏的损害。方法 以１００ｍｇ／ＬＦ－砖茶水喂养Ｗｉｓｔａｒ大鼠３个月后,在透射电镜下观察软骨细胞及肾小管上皮细胞超微结构的变化。结果（１）砖茶型氟中毒大鼠骨组织的损害以骨硬化为主,表现为软骨细胞及软骨基质过早骨化,同时可见,软骨细胞粗面内质网肿胀、扩张。（２）肾脏损害表现为肾近曲小管上皮细胞之线粒体普遍肿胀、扩张,空泡变性,线粒体峪减少或消失。结论 砖茶氟可致骨组织和肾脏损伤,尤其是可损伤其亚细胞膜性结构。     

Demonstration of lymphatics in human synovial tissue

Summary Using a cocktail of monoclonal antibodies PAL-E and DE-U-10 (anti-desmin), combined in double labelling techniques with the lectin Ulex europaeus agglutinin I (UEAI), vessels consistent with lymphatics were demonstrated in normal human synovial tissue. These vessels were negative for the monoclonal cocktail and positive for UEAI, were thin-walled and were located close to deep arterioles and venules as expected. Elastin was not found to assist identification of lymphatics in synovium. In rheumatoid arthritic synovium no vessels staining in the manner of normal lymphatics were found. This may indicate absence or change of phenotype of this type of endothelium in disease.     

Comparison of fluid transport systems in lymphatics and veins

In the anesthetized sheep, pressure pulses generated in the feet are transmitted downstream in the veins but not in the lymphatics at normal intralymphatic pressure. When the sheep is tilted on a tilt table, gravitational changes occur in venous pressure but not in the pressure in adjacent lymphatics. These results suggest that in limb lymphatics, unlike limb veins, the column of fluid is incomplete. This makes extrinsic pumping less effective for propelling fluid in lymphatics than in veins. At normal intralymphatic pressures, intrinsic pumping seems to be mainly responsible for lymph propulsion. The incompleteness of the fluid column in lymphatics might also protect these vessels against the hydrostatic problems experienced by veins during gravitational stress.     

Role of lymphatics in peritoneal dialysis.

There is a renewed interest in understanding the precise role of lymphatics in the ultrafiltration kinetics during peritoneal dialysis. In the normal state, lymphatics draining the peritoneal cavity are the principal means of removal of intraperitoneal isosmotic fluid and macromolecules. During a hypertonic peritoneal dialysis exchange, after peak intraperitoneal volume is achieved, fluid removal proceeds at an almost linear rate, causing intraperitoneal fluid volume to reduce. The isosmotic fluid removal from the peritoneal cavity could occur through the microcirculatory capillaries or through the lymphatic capillaries draining the peritoneal cavity. Animal and human studies suggest that this fluid loss occurs primarily through lymphatics. The two indirect methods of lymph flow measurements, plasma appearance and peritoneal disappearance of tracer colloid, show conflicting results. Although direct measurement of lymph flow rates through cannulation of mediastinal lymph vessels in animals suggests a significant flow through the lymph channels in response to intraperitoneal fluid instillation, lymph flow modification at the lymph node level may prevent use of this technique to assess the precise role played by lymphatics in fluid kinetics during peritoneal dialysis. By analogy with ascites and by extrapolation from previous studies of drain volumes after infusion of isotonic and hypertonic solutions, the average daily lymph absorption rate during CAPD may be predicted to be at least 1 liter per day.     

Structure of lymphatics in the aorta and the periaortic tissues, and vascular lesions caused by disturbance of the lymphatics.

In the cases of obstruction of the lymphatics alone, vascular lesions were slighter compared with those of obstruction of the arterial vasa vasorum (5). However, in the cases of severe disturbances of flow from the vascular wall with marked increase of the connective tissues, vascular lesions such as wide intimal thickening progressed. So, disturbance of lymphatics in the aorta and the periaortic tissue seemed to give an influence on the microcirculation in the vascular wall and vascular lesions.     

Biochemical characterization of some species of Trypansoma (Schizotrypanum) from bats (Microchiroptera).

Trypanosoma (Schizotryanum) species isolated from bats (Microchirotera) in Europe and Latin America were examined by determining the buoyant densities of their nuclear and kinetoplastic deoxyribonucleic acid (DNA) and the electrophoretic patterns of six isoenzymes. By these criteria they were separated into three distinct groups -- two from Europe (T. dionisii and T. vespertilionis) and one from America. T. dionisii was also separable by its morphology in vitro. Geographical location and DNA buoyant densities suggested that the American stocks were more closely related to T. cruzi than to the European species, though they differed from it marginally in kinetoplastic DNA density and in being noninfective to mice. Similar stocks studied by other workers have been shown to differ from T. cruzi also in reduced infectivity to, and lack of natural association with, Triatominae, and in antigenic composition. It is therefore proposed that trypanosomes of the subgenus Schizotryanum occuring naturally in Microchiroptera and differing from T. cruzi sensu stricto as outlined above should be treated as a distinct subspecies, T. cruzi marinkellei ssp. nov. T. cruzi sensu stricto thus becomes the nominate subspecies T. cruzi cruze Chagas 1909.     

维生素C、E对氟中毒大鼠肝、肾、脑组织超微结构的影响

目的 探讨维生素C、E(VC、VE)干预对氟中毒大鼠肝、肾和脑组织超微结构变化的影响.方法 将120只Wistar大鼠分为9组.对照组饮用纯净水;染氟组饮用高氟水(含氟化钠150 mg/L).染氟同时.VC干预组分别用50、100、150 mg·kg-1·d-13种剂量的VC灌胃;VE干预组分别用25、50、75 mg·kg-1·d-1 3种剂量的VE灌胃;VC和VE联合干预组以100 mg·kg-1·d-1VC和50 mg·kg-1·d-1VE同时灌胃.9个月后处死大鼠,用透射电子显微镜观察各组大鼠肝、肾、脑组织超微结构变化.结果 大鼠饮用高氟水后.肝、肾、脑组织发生了不同程度的超微结构病理变化.①肝细胞水肿,线粒体基质变淡,在肝细胞内可见脂滴,核基质淡,核仁边集.肝血窦内皮明显肿胀; ②肾小管细胞核异染色质较多且边集,细胞间隙和质膜内褶增宽,内质网扩张,集合管上皮细胞内的亮细胞胞质极度松散;③脑胶质细胞肿胀,细胞器很少,细胞核异染色质较多、边集.VC、VE各干预组肝、肾、脑组织超微结构变化轻微或无明显变化,其中VC、VE联合干预组各组织超微结构基本与对照组相同.结论 氟中毒可引起大鼠肝、肾、脑组织损害.VC、VE单独及联合干预均对氟中毒引起的组织器官损害有一定的保护作用,联合干预效果强于单独干预.     

Cardiac lymph and lymphatics in normal and infarcted myocardium

Cardiac lymphangiography was applied to 29 normal dogs (ND) and 14 dogs following acute coronary occlusions. In five of the ND, lymph collected from infarcted dogs was selectively injected into the coronary artery prior to the lymphangiogram. In ND, the lymphatic density (LD) was 6.6% ventricular area (VA).Acute coronary occlusion induced a change in the LD. The infarcted zone registered a decrease in LD (3.6% of VA p <0.001 vs ND). Hyaluronidase increased LD in normal dogs (13.8% of VA p < 0.01 vs ND). Hyaluronidase pretreatment increased the LD in infarcted myocardium (20.9% of VA, p < 0.001 vs non-treated infarcts). No difference was seen between uninfarcted areas of treated and nontreated animals. (10.6% vs 11.2% of VA). Lymph was collected from cardiac lymphatics in five dogs before and after coronary occlusion. When selectively injected into coronary arteries of ND, post-infarct lymph induced ECG changes of ischemia, arrhythmias, and increased the LD (14.6% VA, p < 0.001 vs ND). The results suggest (1) Cardiac lymphatics are altered in the uninfarcted and infarcted zones following coronary occlusion. (2) Hyaluronidase preserves the lymphatic density in infarction. (3) Lymph collected from zones of infarction is toxic.