Ultrastructure and segmentation of microdissected kidney tubules in the marine flounder, Pleuronectes platessa

A new method combining electron microscopy with microdissection was used to study the segmental variation along the tubule of a marine flounder. Two different nephron types were present. One type had long tubules with the glomeruli located close to the kidney surface. The other type had shorter and more coiled tubules with the glomeruli located close to the terminal end of the same nephron. Five different segments were present: (1) neck segment, (2) first proximal segment, (3) second proximal segment, (4) third proximal segment, and (5) collecting tubule. The third proximal segment was not present in all tubules. An extensive system of infoldings from the plasma membrane was present in all segments, except the neck segment and the collecting tubule. Tight junctions impermeable to lanthanum were present in all segments. The collecting duct cells also had extensive infoldings from the plasma membrane and tight junctions impermeable to lanthanum were also present here.

Neurochemical anatomy of the neuroendocrine hypothalamus. Neurochemical anatomy of the hypothalamus

Microdissection techniques for isolated removal of the various regions of the hypothalamus as well as the individual hypothalamic nuclei are detailed. Recent development of biochemical microassays have made it possible that the concentrations of neurohormones, neuropeptides, neurotransmitters and their related enzymes could be detected in such a small volume of brain tissue than the hypothalamic nuclei. Data available of the hypothalamic distribution of above substances are summarized. The possible role and origin of intra- and extrahypothalamic neurohormones as well as the existence of the so-called "hypophysiotrophic area" are discussed.

Cochlear and vestibular lesions in capsular otosclerosis as seen in microdissection

In 24 temporal bones from patients with otosclerosis prepared by the method of microdissection and surface preparations, otosclerotic foci could be clearly seen during removal of the otic capsule. The state of activity of each focus was estimated on the basis of its consistency and vascularity. Small anterior foci constituted the most common form of involvement of the otic capsule. All were judged to be inactive, and none of them appeared to have caused obvious sensorineural degeneration. No cases of "pure cochlear otosclerosis" were seen. Sensorineural degeneration was associated with large anterior foci which reached the upper basal turn. One specimen displayed a circumscribed sensorineural degeneration in the upper basal turn, with an almost exact correspondence between the location and extent of the cochlear lesion and the site of invasion by the otosclerotic process in the bone and endosteum bordering on scala media and scala tympani. It is postulated that a toxic factor had diffused from the focus and acted directly on the organ of Corti. When multiple foci were present they were usually poorly defined. The otosclerotic process involved the round window, with new lamellar bone formation in the scala tympant of the lower half of the basal turn. The most extensive sensorineural degeneration in the entire material was seen in this group. One specimen also had severe cochlear hydrops. In three specimens large shunts were observed to connect the otosclerotic foci with the cochlear vasculature, which was severely dilated. Where otosclerosis involved the endosteum of the scala tympani, loss of vessels was observed. One specimum with extensive active capsular otosclerosis had severe sensorineural degeneration of the vestibular system. Vestibular pathology in fenestrated ears is also described. In a specimen from a patient with no caloric reaction, numerous hair cells were present in the macular organs.

Clinically important structures of the equine hock

A study method has been devised to review clinically important structures of the equine hock joint on a fresh specimen. The review can be done alone; dissection takes about 2 hours; special tools or materials are not required.

The effects of extraperiosteal and subperiosteal dissection. II. On fracture healing

The effects of subperiosteal and extraperiosteal dissection on the healing of tibial osteotomies were studied in fourteen rabbits killed three weeks after the osteotomy. Of the tibiae exposed subperiosteally, 71 per cent healed; of those exposed extraperiosteally, only 7 per cent had solid union. The first group had a significantly lower level of hydroxyproline in the callus and higher values for breaking load, breaking strength, and absorption of energy to failure. In ten animals that also had muscle transection at the osteotomy site, the rate and type of healing was similar whether no dissection, subperiosteal dissection, or extraperiosteal dissection had been done, but the callus showed lower calcium levels and higher hydroxyproline levels than in either of the groups with muscle trauma. This implies retardation of healing caused by muscle injury. Our data suggest that in the absence of muscle damage, subperiosteal dissection results in earlier healing than does extraperiosteal dissection. Muscle transection markedly retards healing; then, after transection, neither type of dissection appears to retard healing more than the other.

The effects of extraperiosteal and subperiosteal dissection. I. On blood flow in muscle

Blood flow was studied in traumatized and untraumatized flexor digitorum longus muscles of rabbits before and after surgical dissection of the periosteum of the tibia. Neither extraperiosteal nor subperiosteal dissection diminished blood flow in untraumatized muscles, but when the muscles had been crushed, only extraperiosteal dissection appeared to severely compromise their collateral circulation. Because subperiosteal dissection did not diminish the blood flow in injured muscles, it seems to offer some advantages as a surgical approach to bone in a severely traumatized extremity.

Technique for microdissection and measurement in biopsies of human small intestine

A microdissection and measurement technique has been adapted for biopsy of human small intestine. Specimens fixed in alcohol and acetic acid are Schiff stained in bulk. Villi and crypts are then dissected out under a dissecting microscope, placed under a coverslip, examined, measured, and the number of mitoses in individual crypts counted. With this method specimens of normal small intestine have been found to have villi 500 microns to 1100 microns long and crypts 150 microns to 300 microns. These values were double those obtained when measuring sections of the same specimens stained with haematoxylin and eosin. The mean number of mitoses per crypt in normal duodenum and jejunum ranged from 1 to 12 and most of the cells in mitosis were in prophase or telophase. This rapid, sensitive, and inexpensive technique complements the available methods of measuring small intestinal architecture.

Mediastinal dissection--1976: indications and newer techniques

Head and neck neoplasms may invade the mediastinum by direct extension or metastases to the tracheoesophageal or jugulo-subclavian lymph nodes. The clavicles and manubrium are a barrier to adequate resection in this type of disease. In 1962, the senior author reported six mediastinal dissections for stomal recurrences after laryngectomy. Later techniques for staging the removal of manubrium and clavicles and preparing the regional flaps were devised to avoid major complications arising from operating in this area which usually had prior treatment with radiation and/or surgery. Over 60 transsternal radical neck dissections have been performed in the past 20 years. We have in the past evaluated the morbidity and survivals in stomal cases and present here our revised indications and techniques.

A retropharyngeal approach to the avian brain stem

The surgical steps used to expose the ventral surface of the chicken's rhombencephalon are detailed. Both acute and chronic experimental preparations can be obtained with this technique. Text material and illustrations provide information on the morphological relationships of the brain stem, skull and other significant structures encountered during the operative procedure.

Modified tannin-osmium conductive staining method for non-coated scanning electron microscope specimens. Its application to microdissection scanning electron microscopy of the spleen

Supplement of guanidine hydrochloride to the original tannic acid solution of MURAKAMI (1973) eliminated, without debilitating the conductivity effect, the vexatious treatment with different amino-acids and sucrose in the previous method (MURAKAMI, 1974). The procedures and advantages of this simplified modification are described using human spleen samples; attempt was made to elucidate the structure of arterial terminals by dissecting the specimens under the scanning electron microscope.

Necropsy of animals for scientific research

Techniques for the necropsying of animals and the trimming of tissues for histologic sections have been described for scientific research. It has been helpful to refer to the description, records, fixatives, and to other special procedures. The comment explains the reasons for using some of the procedures.

Isolation and long term preservation of pancreatic islets from mouse, rat and guinea pig

This paper reports techniques for the isolation and long term preservation of pancreatic islets from the mouse, rat and guinea pig. Islets have been isolated using a modification of a free hand microdisection procedure described by Hellerström in 1964 [1]. Isolated islets have been subjected to three preservation systems and their viability following storage assessed by light microscopy of sections stained with Gomor's aldehyde fuchsin [2] and by measuring the insulin release from islets in vitro in response to a glucose stimulus. The systems were: a) Simple cold storage in Hank's balanced salt solution at 4 degrees C. Following 15 h cold storage, histological and functional survival was 100%. This dropped to 10% at 48 h. There were no survivors following 72 h storage. b) Sub zero cell storage. In Group I (freezing rate 1 degrees C/min) histological survival was 35% and functional survival 20%. In Group II (freezing rate 5 degreees C/min with 24 h culture period after rewarming) histological survival was approximately 87% and functional survival 75%. c) Organ Culture. Islets from the guinea pig, rat and mouse showed minimal morphologic damage when cultured for 21 days in a simple organ culture system. At 28 days, histological survial was approximately 30%. Following organ culture we were unable to correlate histological and functional survival.

Dissecting ocular tissue for intraocular drug studies

This report describes a convenient reproducible ocular dissection technique which has important applications for ocular antimicrobial penetration studies. Different ocular tissues can be sectioned while frozen and then plated directly on culture medium containing the test organism; after the zones of bacterial inhibition are measured at 18 hours following incubation, the tissue specimens are weighed providing more reliable evidence regarding drug concentrations. In such a fashion, a drug can be administered topically, subconjunctivally, or systematically, and assayed from the cornea to the optic nerve at various time intervals. Analysis of antibiotic in the vitreous body, which has important application in the therapy of endophthalmitis, can be routinely performed in the experimental model.

Dissection casts of the human brain

A simple, inexpensive method of making accurate permanent casts of brain dissections is described. Dissected brain preparations are used to produce silicone rubber molds. Methyl methacrylate is used to make the hard plastic models.

Scanning electron microscopy of epithelia prepared by blunt dissection

Simple dissection techniques of samples to be examined in the scanning electron microscope allow one to visualize easily the three-dimensional shape of epithelial cells in situ. Such preparations reveal a complex system of ridges and folds on the lateral surface of the cells whose intricacy can best be appreciated with SEM. In many epithelia there is a smooth apical band which corresponds to the region occupied by the junctional complex previously identified with conventional EM techniques. The secretion of chylomicra that result from a fatty meal can be observed. It is possible to study the distribution of concanavalin A binding sites on the lateral surfaces of the cells utilizing hemocyanin as a marker. In the case of the proximal tubule epithelium, the apical cell surface has many more binding sites than the lateral cell surface and there is a sharp demarcation at the level of the apical band. After blunt dissection the relationship of the basal surface of the cells with the basement lamina and the basement membrane can be appreciated as well. Possible physiological meaning of the morphological features observed is briefly discussed.

A precision microdissection procedure for undecalcified bone thin sections

A procedure is described for removing osteons from undecalcified, thin sections of bone. The method involves the use of a microdrilling machine in combination with a micromanipulator. The procedure allows a substantial reduction in the time required for microdissection over previously described methods while permitting the irregular contours of osteons to be followed with precision.

The lobes of the human prostate

A dissection technique for the huamn prostate has been developed on about one hundred male autopsies, which makes it possible to delimit two dorsal, two lateral and two median lobes, each with separate ducts. It was found that both the dorsal lobesand the lateral lobes join dorsally to the ejaculatory ducts. The median lobes are situated below the medial parts of the seminal vesicles, and are closely apposed both ventrally and dorsally of the ejaculatory ducts. The ability to delimit the prostatic lobes in man may offer new opportunities to study the relation of prostatic diseases to different lobes as well as the hormonal dependency of the separate lobes.

Scrotal pouch techniques. Adjunct to orchiopexy

Following orchiopexy, contraction of dartos and cremaster muscles may pull the testis toward the external inguinal ring. Fibrous tissue deposition resulting from testis mobilization and cord skeletonization may bind the testis in an unfavorably high scrotal position. The "scrotal pouch technique," utilizing both a subcutaneous scrotal pocket for the testis external to the dartos layer and a gentle testis traction regimen, serves to diminish the chances of testis retraction after orchiopexy.

Endoscopic decompression for intermetatarsal nerve entrapment--the EDIN technique: preliminary study with cadaveric specimens; early clinical results

The authors have developed an endoscopic approach to the surgical treatment of Morton's neuroma. This technique is based on the premise that the condition is primarily a nerve entrapment disease. As with other endoscopically assisted procedures, the authors believe that this technique will be less traumatic, allowing an earlier return to normal activity, with less patient discomfort than with traditional surgical techniques.