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Biomedical subjects

D W Hamilton

Publications and source records attributed to D W Hamilton.

At least 55 records · Page 3Linked to original sources
PubMed1982

Immunocytochemical evidence for the specific localization of aldose reductase in rat Sertoli cells.

Evidence that the enzyme aldose reductase (AR) is specifically located in Sertoli cells is presented by means of an established immunocytochemical technique and with a variety of approaches. By staining tissue sections, the enzyme was shown to be present in Sertoli cells at birth and the intensity of the immunocytochemical stain increased by 5 days of age to that found in the testes of older rats. By means of enzyme dispersion of mature testes; the culture of enriched Sertoli cell preparations from the testes of immature rats; and the collection of newly released testicular spermatozoa in rete testis fluid, it was shown that immunoreactive AR was not present in any testicular cell type except the Sertoli cell. The significance of the specific localization in Sertoli cells of a principal enzyme concerned in the sorbitol or polyol pathway for the conversion of aldose sugars to their corresponding ketoses is discussed.

Aging↗
PubMed1979

Morphology of the epithelium of the extratesticular rete testis, ductuli efferentes and ductus epididymidis of the adult male rabbit.

The fine structure of the epithelium lining the extratesticular rete testis, ductuli efferentes and ductus epididymidis of the rabbit has been investigated. In the ductuli efferentes the epithelium is composed of two cell types, principal cells and ciliated cells. The latter type is distinguished from principal cells by the presence of cilia projecting into the lumen and the position of the nucleus in the apical half of the cell. Principal cells in this segment are characterized by micropinocytotic vesicles on the surface plasma membrane and a variety of small dense bodies scattered throughout the cytoplasm. In the ductus epididymidis basal cells replace ciliated cells as the second cell type, but differences between various segments of the epididymis are related to the fine structure of the principal cells. In the proximal caput epididymidis (Nicander's region 1) the principal cells are tall with long microvilli. They typically contain a small Golgi apparatus and a cluster of dense bodies adjacent to the nucleus. In the distal caput epididymidis (Nicander's regions 2-5) the apical cytoplasm of principal cells is filled with numerous micropinocytotic vesicles and large multivesicular bodies; these features are interpreted as signs of absorptive activity. The multivesicular bodies are absent from the cytoplasm of principal cells in the corpus epididymidis (Nicander's region 6) and, instead, numerous elements of smooth endoplasmic reticulum, a large Golgi apparatus, lipid droplets and dense bodies characterize principal cells in this segment. Towards the proximal cauda epididymidis (Nicander's region 7), the number of dense bodies (lysosomes) in the cytoplasm increases considerably. In the globose cauda (Nicander's region 8), the principal cells are reduced in height, and in addition to the features described in region 7, are characterized by a concentric array of rough endoplasmic reticulum in the basal cytoplasm. These observations are discussed in relation to the role of the epididymis in promoting the maturation and survival of spermatozoa.

Animals↗
PubMed1979

Gastro-colic fistula complicating benign gastric ulcer in analgesic abusers.

Two cases of gastro-colic fistula occurring in analgesic abusers are described. In both patients, the fistulous communication was diagnosed at endoscopy and subsequently verified by upper gastrointestinal tract barium studies. Gastro-colic fistula is a rare complication of benign peptic ulcer disease. Whilst salcylates and cortico-steroids have been implicated as aetiological agents, abuse of compound analgesics has not previously been reported. Since the first description of gastro-colic fistula in 1755, thirty documented cases associated with benign gastric ulcer have been reported. Most often, gastro-colic fistula occurs secondary to gastric or colonic malignancy. Barium enema examination is the most accurate diagnostic study. Endoscopy has been confined to the visual inspection of the ulcer and establishing the benign nature of these lesions.

Adult↗
PubMed1978

Gross and histological variations along the length of the rat vas deferens.

The gross morphology of the vas deferens of the rat and the changes that occur along its length are reported. It is shown that the organ can be divided into proximal, distal and terminal portions. Each portion is histologically unique and is situated in a different part of the body. The differences are discussed in relation to the function of the organ and their possible role in the consequences of vasectomy.

Animals↗
PubMed1977

Obstruction of the gastrointestinal tract by foreign bodies in adults.

Foreign bodies may become impacted because of congenital or acquired narrowing of the gastrointestinal tract or owing to unusual physical characteristics of the ingested material. Active intervention is necessary when impaction is complicated by intestinal obstruction or perforation or when the foreign body is composed of a toxic substance.

Adult↗
PubMed1977

Immediate sterility after vasectomy.

Phenyl mercuric nitrate as an injection, in a dilution of 0-02% and buffered to pH 7, is a potent spermicidal agent which has been demonstrated to have no harmful side effects. It produces rapid death of all spermatozoa on contact. The injection of 2-5 ml of the solution into the lumen of each vas at the time of vasectomy is a simple procedure and adds no significant time and no complications to the operation. Studies have shown that no viable spermatozoa were present at seminal counts carried out one or two weeks after operation.

Humans↗
PubMed1977

Observations on destruction of spermatozoa in the cauda epididymidis and proximal vas deferens of non-seasonal male mammals.

The electron microscope has been used to examine luminal spermatozoa from the cauda epididymidis and proximal vas deferens of rats, mice, hamsters and guinea pigs. Free in the lumen of all species are accumulations of a dense material within which are vesicles, granules and dense bodies, as well as spermatozoa. The spermatozoa are undergoing a process of degeneration as judged by a loss of plasma membrane from both heads and tails and further disruption of acrosomal membranes, mitochondrial sheaths and outer dense fibers. Disruption of spermatozoa also occurs outside these obvious dense masses when the luminal protein precipitated by the fixation procedure has contact with the spermatozoon. Intact spermatozoa are separated from luminal material by a clear "halo".

Animals↗
PubMed1977

Phagocytosis of spermatozoa in the terminal region and gland of the vas deferens of the rat.

The existence of a discrete group of cells that are able to phagocytose spermatozoa is reported in the terminal vas deferens of the rat. In addition it is shown that phagocytosis of spermatozoa occurs in the gland of the vas deferens. The cytological mechanisms involved in the phagocytotic process are discussed, and the role that this activity may have on the removal of surplus spermatozoa is discussed.

Animals↗
PubMed1977

Regional variation in the surface morphology of the epithelium of the rat ductuli efferentes, ductus epididymidis and vas deferens.

The luminal surface of epithelial cells lining the ductuli efferentes, ductus epididymidis and first portion of the vas deferens were studied with the scanning electron microscope. In ductuli efferentes obvious ciliated cells are identified and it is shown that on non-ciliated cells the short microvilli adhere to one another to form clumps of microvilli. In the epididymis two cell types are described and can be identified as principal cells and clear cells based on the presence or absence of microvilli. Clear cells vary in number along the duct, being most numerous distally. Their surface morphology is also most variable distally. In the vas deferens, principal cells with surface microfilli are easily identified; but, in addition, a second cell type is seen, the identity of which is not known.

Animals↗