Search PubMed⌕ Search

Biomedical subjects

K C Hodde

Publications and source records attributed to K C Hodde.

17 recordsLinked to original sources
PubMed1996

Coronary artery bypass grafting without cardiopulmonary bypass and without interruption of native coronary flow using a novel anastomosis site restraining device ("Octopus").

OBJECTIVE: This study assessed the feasibility of coronary artery bypass grafting on the beating heart without interruption of native coronary blood flow using a novel anastomosis site restraining device. BACKGROUND: Recently, an end-to-side bypass technique was described that does not require interruption of flow in the recipient artery. METHODS: By means of a suction device ("Octopus"), in 31 pigs the epicardium was grasped and immobilized through an arm contraption fixed to the operating table. In the first 15 consecutive pigs (study I), the two-dimensional motion of an epicardial beacon was monitored. In 16 subsequent pigs (study II), an internal mammary artery was grafted under the microscope in two steps to a proximal coronary artery segment, without cardiopulmonary bypass. First, the internal mammary artery was sutured end-to-side to the outside of the coronary artery. Secondly, an orifice was punched in the partitioning coronary wall by an excimer laser catheter introduced through a temporary side-branch of the internal mammary artery. RESULTS: Study II: During 43 suction periods in four anastomosis areas, immobilization was achieved for 15 to 169 min (>30 h in total) in 13 open- and 9 closed-chest procedures without hemodynamic deterioration. The area circumscribed by the edges of the beacon trajectory (area in which the anastomosis is to be tracked) was reduced from 73.0 +/- 43.0 mm(2) (mean +/- SD) to 1.3 +/- 0.5 mm(2) (p<0.001) in the open-chest and to 0.2 +/- 0.2 mm(2) in the closed-chest procedure. At 6 weeks, no myocardial or coronary suction lesions were found. Study II: Nonocclusive anastomosis surgery required 25 +/- 3 min. No leakage, serious arrhythmias, graft closure or hemodynamic deterioration occurred during the procedure or for 2 h after ligating the coronary artery proximally. At 6 weeks, all seven grafts were patent. CONCLUSIONS: Coronary bypass on the beating heart without interruption of coronary flow is feasible. In both open- and in closed-chest procedures, the "Octopus" reduced anastomosis site motion to about 1 X 1 mm without adverse consequences.

Anesthesia, General↗
PubMed1995

Experimental retroperitoneal endoscopic surgery.

Techniques for retroperitoneal endoscopic procedures with the patient in prone position were evaluated in experimental studies in the pig. Nephrectomy, para-aortic lymph node dissection, lumbar sympathectomy and assisted aorto-femoral bypass were performed and the experience is reported herein. The prone position contributes to the creation of the retroperitoneal working space and eliminates the need for extensive retraction and thus for additional ports. The modified open Hasson technique was found to be the preferred retroperitoneal access procedure.

Animals↗
PubMed1990

Advances in corrosion casting methods.

This paper briefly discusses the concept of corrosion cast preparation (primarily of blood vessels), the use of the scanning electron microscope (SEM) to study these casts and the observations which can be made, together with the merits and the limitations in various applications. A number of reviews and surveys are quoted in which the different injection media, injection methods, animal preparations and corrosion procedures are described. A new procedure of cleaning the corrosion casts with sodium hydroxide and Triton X-100 is described. The observations which can be made are listed and illustrated both on the cellular level as well as in organ systems as a whole. The discussion centers around some common misconceptions, the feasibility in various applications and the limitations of the method. The conclusion is that the method has proven to be useful especially in conjunction with other methods. Moreover, while the concept of the method may be very straight-forward the approach and the interpretation often need careful consideration and might not be as straight-forward as one tends to expect from the simple sounding principle.

Animals↗
PubMed1990

The morphology of synovial lining of various structures in several species as observed with scanning electron microscopy.

Data concerning surface morphology of synovial lining of tendons, tendon sheaths, cruciate ligaments, infra-patellar fat pads and peripatellar synovial ridges in various species (rat, rabbit, dwarf goat, sheep, pig, dog, human) are reported on. Supportive studies with transmission electron microscopy (TEM) and light microscopy were performed. Three principal morphological appearances of the synovium are evident. On structures with a dense fibrous architecture like tendons, tendon sheaths and cruciate ligaments the intimal cells and processes are mostly slender and may tend to orientation in the length-axis of the structure. On the peri- and infrapatellar adipose tissues two principal 'extremes' are seen: one in which the contours of the fat cells are clearly visible with fungoid shaped structures in between them, and one in which the fat cell contours are not recognizable and the intima consists of cauliflower-like cells. Transitional forms exist. Several features observed on tendons and tendon sheaths which have not been reported on before are presented in this paper. A consistent classification of synovium is presented.

Animals↗
PubMed1987

Vascular corrosion casts of the dog testis after experimental microvascular surgical orchiopexy. A scanning electron microscope study.

Five mongrel dogs underwent microvascular surgical orchiopexy by anastomosing the testicular artery and vein with the respective caudal epigastric vessels. In order to assess the effect of a 40 to 50-min period of warm ischaemia (the time required to make the anastomosis) on the testicular blood vasculature, plastic corrosion casts were made of the operated testes and compared with non-operated control specimens. The resulting blood vessel casts were inspected in the scanning electron microscope. One case of testicular atrophy developed, caused by a postoperative wound abscess. Comparing operated with non-operated testes, no differences in vascularisation, pattern or density of arterial supply, capillary network and venous drainage were seen. These findings are in agreement with data from the literature concerning histological, hormonal and clinical results.

Anastomosis, Surgical↗
PubMed1987

Vasculature of the crista ampullaris of the rat as seen in microcorrosion casts.

A scanning electron microscope study of corrosion cast preparations of the vessels of the crista ampullaris was carried out in adult rats. This method shows the microvasculature of the cristae in the three-dimensional model. As a result of this technique we have been able to demonstrate on microscopical level a particular microvasculature in the septum cruciatum of the crista in rat.

Animals↗
PubMed1987

Effect of intracranial pressure on bridging veins in rats.

The behavior of bridging veins at their entrance into the superior sagittal sinus during elevated intracranial pressure (ICP) was investigated in rats using a cranial window and infusion of mock cerebrospinal fluid. The bridging veins became slightly smaller as the ICP rose (maximum reduction 17%). Compression or collapse of the veins was not observed, even at an ICP level of 100 mm Hg, and there was no cuffing of bridging veins upstream of the entrance. Both the scanning electron microscopic investigation based on resin vessel casts and the histological examination of whole-head coronal sections indicated that the narrowest points of the bridging veins are at their entrance to the superior sagittal sinus, caused by the oval aperture with thickened wall structure in the lateral sinus wall to which the bridging veins are connected. The present data thus support the concept that cerebral blood flow during intracranial hypertension is not reduced by venous cuffing or compression of the lateral lacunae and bridging veins; by contrast, the arteriovenous pressure difference seems to remain the determining factor even at high ICP. Thus, blood flow through the brain stops when ICP approaches the level of blood pressure.

Animals↗
PubMed1987

Vascular changes in popliteal lymph nodes due to antigen challenge in normal and lethally irradiated mice.

The microvascular system of the murine popliteal lymph node was investigated using scanning electron microscopy of microcorrosion casts. Time-dependent changes in the microvasculature following regional antigen challenge in normal and lymphocyte-depleted mice were studied. Normal lymph node microvasculature exhibited a significant increase in both the vascular bed and post-capillary venules containing high-endothelium in response to antigen challenge. Lymph nodes of lymphocyte-depleted mice showed no microvascular size increase following antigen challenge and a reduction in the amount of high-endothelium was observed.

Animals↗
PubMed1986

The angioarchitecture of the choroid plexus of the lateral ventricle of the rabbit. A scanning electron microscopic study of vascular corrosion casts.

The vascularization of the choroid plexus of the rabbit's lateral ventricle has been studied by scanning electron microscopy of vascular corrosion casts. Based on the vascular patterns discerned, the plexus was subdivided into 6 different parts: the inferior, lateral, central and superior parts, the free margin and the lingula. These differ in structure and localization. While the arterial supply of the inferior part is via the anterior choroidal artery, the central and superior part are supplied by the posterior choroidal arteries. Three main veins leave the plexus and drain to the basilar vein from the inferior part and to the internal cerebral vein from the inferior, central and superior part. Capillary diameters were typically 10-15 micron. Regular nodular thickenings up to 24 micron in diameter were seen in the free margin and the superior, lateral and inferior parts. 'Garland' shaped capillary configurations sheathing arteries as well as veins were found all over the plexus. It is suggested that these 6 different parts of the plexus described here may reflect functionally different areas.

Animals↗
PubMed1986

A study of valve incompetence that developed in an experimental model of venous hypertension.

Surgical treatment of venous valve incompetence should be aimed at restoring the underlying valve defect. For a better definition of the structural anatomical defects in acquired valve incompetence, an experimental study was performed with 40 rats. Venous valves were subjected to hemodynamic stress by creating femoral arteriovenous fistulas. The resulting valve incompetence was studied by using descending phlebography and a casting technique, which allowed for an accurate description of leaking valves when the scanning electron microscope was employed. A three-dimensional insight of the morphology of incompetent venous valves was obtained. A description of short- and long-term (two to four months) changes in valve architecture was also obtained; initially, there was retrograde passage of fluid through a separation of the cusps' free border. The cusps' bulgings were still clearly defined after two months, and, at this stage, commissures had started to widen. After a four-month period, commissures were lost and no recognizable valve sinus was present.

Animals↗
PubMed1985

Microvasculature of the stria vascularis in the round window area in the rat. A scanning electron microscopy study.

This paper reports the results of a scanning electron microscopy study of corrosion cast preparation of the vessels in the cochlea of the rat. This method confirms the general findings about the cochlear vascularization, but also gives the opportunity to study the detailed pattern of the vascular supply of the stria vascularis in the round window area. The basal end of the stria vascularis has a remarkably different vascular anatomy compared with the other areas of the cochlea. The possible role of the vessels in the round area is discussed.

Animals↗
PubMed1981

Ascending spinal systems in the nurse shark, Ginglymostoma cirratum.

The ascending spinal systems in the nurse shark were studied after spinal hemisections by use of the Nauta and Fink-Heimer techniques. The dorsal funicular fibers form a single bundle issuing fibers to the gray substance of the spinal cord, the dorsal funicular nucleus, and the vestibular complex. Some dorsal funicular fibers also appear to contribute to the spinocerebellar tract. The degenerated lateral funicular fibers are segregated into three fasciculi issuing fibers medially as they ascend through the brainstem. The largest target of these fibers is the reticular formation, but diffusely organized axons also reach 1) the gray matter of the spinal cord, 2) the dorsal motor nucleus of the vagus, 3) the nucleus "A" of the medulla oblongata, 4) the central gray substance of the brainstem, 5) the cerebellar cortex, 6) the cerebellar nucleus, 7) the nucleus intercollicularis, 8) the mesencephalic tectum, and 9) the dorsal thalamus. At the latter site the spinal input appears to partly overlap with the visual input. The results, compared with the strikingly similar findings in other classes of vertebrates, indicate that all vertebrate groups apparently have the same basic components of ascending spinal projections.

Animals↗
PubMed1980

SEM of micro-corrosion casts.

The production of micro-corrosion casts suitable for scanning electron microscopy (SEM) is described in this tutorial. The casts are produced by filling an internal luminal system or space with a liquid medium which becomes solid in situ. The surrounding tissue is then removed (corroded) and the resulting replica is dried, rendered conductive, and examined in the SEM. An historical review describes the evolution of the technique and provides perspective for the SEM applications. The criteria which should be fulfilled by the injection medium are listed, and the procedures used for those media which have proven successful, together with their inherent artefacts are described in detail. The two groups of media most commonly used are the rubber compounds and the polymer resins. The latter so faithfully replicate luminal surfaces that a distinction between arteries and veins can be made on the basis of endothelial cell impressions on the surface of the replica. A review of currently used non-SEM techniques provides a comprehensive analysis of the methods used to determine success with SEM micro-corrosion casting, as well as complementary methods for the visualization of vascular and alveolar systems. The paper is illustrated mainly with material from the rat brain vascular system.

Animals↗
PubMed1979

The vascularization of the pineal gland (epiphysis cerebri) of the rat.

The vascularization of the rat pineal gland was investigated with, respectively, latex and resin injection preparations of the cephalic blood vessels in adult Wistar rats. From the dissection of the latex-injected and aldehyde-fixed rat brains under the stereo light microscope it was found that the arterial supply comes exclusively from separate branches of the posterior cerebral artery. The pineal area was dissected out from the resin injected and corroded specimens under the stereo light microscope and was inspected in the SEM. The supplying arteries, identified on the basis of their endothelial cell imprint patterns, were 4 to 6 in number with a diameter of 20 to 40 micron. The venous drainage consisted of 12 to 16 short veins with a diameter of 40 to 60 micron, all draining directly into the great cerebral vein and thereafter via the sinus influens immediately into the systemic venous circulation.

Animals↗
PubMed1978

Scanning electron microscopy of the cochlear vasculature.

Studies on the vascularization of the cochlea with conventional injection methods that use light microscopy have failed in viewing both the overall three-dimensional picture, as well as the detailed construction of the cochlea vascular blood vessels. This basic shortcoming can be omitted by the use of scanning electron microscopy (SEM) on corrosion casts, which only presently has been introduced. The use of a commercial resin (Mercox) as an injected medium, followed by application of macerating fluids, provides clean and completely filled casts of the cochlea vascular system, which can then be inspected by SEM. This method not only confirms the general findings about cochlea vascularization but gives the opportunity to view the overall picture, as well as the detailed pattern of the intricate cochlear capillary beds.

Animals↗