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Biomedical subjects

L Johnson

Publications and source records attributed to L Johnson.

At least 451 records · Page 25Linked to original sources
PubMed1978

Ultrastructure of fallopian tube carcinoma.

Fallopian tube carcinoma is one of the rarest of primary gynecologic malignancies. Normal tubal epithelium is composed of secretory, ciliated, and intercalary cells. To determine the cellular composition and ultrastructural details of this rare neoplasm, a moderately well-differentiated tubal carcinoma was studied with the electron microscope. A prominent feature was the formation of numerous ultramicro alveolar spaces lined by cell surface microvilli. The nuclei of the neoplastic cells demonstrated a variety of fine structural abnormalities. Based on cell size and shape criteria, a possible dual tumor cell population was suggested. However, no cilia were seen in any of the tumor cells and almost all were devoid of secretory granules. These latter observations suggest that this tumor was primarily a proliferation of intercalary cells.

Aged↗
PubMed1978

Small-intestinal mucosa in pseudoobstruction syndromes.

The purpose of this investigation was to determine the frequency and severity of small intestinal mucosal damage in pseudoobstruction syndromes. One hundred eighty-nine interpretable biopsies from 12 patients were blindly reviewed by two investigators. The underlying disorders were scleroderma in 7 and idiopathic intestinal pseudoobstruction in 5. All 12 had small-intestinal dilatation on small-bowel series. Eight of the 12 patients had biopsies characterized by moderate to severe mucosal damage; 3 of these had some biopsies which were flat. The damage did not correlate with: (1) types and numbers of organisms recovered from small intestinal aspirates; (2) duration of illness; (3) degree of dilatation of the proximal small bowel; (4) concentrations of deconjugated bile salts in small intestinal fluid; or (5) amount of fat absorbed in fat-balance studies. We conclude that mucosal damage is common in pseudoobstruction syndromes. The pathogenesis of the damage and its relationship to intraluminal bacteria remain undefined.

Adolescent↗
PubMed1978

Characterization and application of a radioimmunoassay for reduced, carboxymethylated human luteinizing hormone alpha-subunit.

We have established a double antibody RIA using a rabbit antiserum prepared against reduced, carboxymethylated (RCXM) human LH alpha-subunit, with RCXM-alpha as tracer and standard. This antiserum did not cross-react with any native gonadotropins or subunit, and reacted only weakly with RCXM-alpha. A tryptic digest of RCXM alpha-subunit was completely reactive, while chymotryptic digestion abolished all immunoreactivity. By testing with separate tryptic fragments, the recognition site could be localized to a segment close to the amino-terminus of the peptide chain. When applied to measurement of serum and urine, an immunoreactive species, parallel to RCXM alpha-subunit by serial dilution, was found in concentrations of 1-2 ng/ml in serum and 3-4 ng/ml in urine. Similar levels of the immunoreactive component were found in conditions of elevated gonadotropins (e.g. pregnancy) as well as gonadotropin deficiency(panhypopituitarism and Kallmann's syndrome). After stimulation with LHRH, no rise was noted at times up to 6 h despite the fact that both LH and LH-alpha were elevated. The data indicate that the sequence-specific antiserum may be detecting an immunoreactive form of alpha-subunit of LH whose kinetics of appearance and disappearance differs from those of the native subunit.

Amino Acid Sequence↗
PubMed1978

Experimental studies on fluid pathophysiology in small intestinal obstruction in the rat. I. Effects of intraluminal hyperosmolality.

An experimental model is described which is intended to simulate and accentuate the movement of fluids across the intestinal mucosa resulting from simple small intestinal obstruction as well as to provide a means for measuring these fluid shifts. Working on the hypothesis that the increase in fluid in the obstructed small intestine is a consequence of increased osmolality resulting from enzymatic breakdown of the intestinal contents, a solution of high osmolality was introduced into an intestinal segment of known size and position. Under these conditions the intestinal mucosa functioned in the manner of a semipermeable membrane and permitted only fluids of low osmolality to enter the intestinal lumen, thus tending to normalize its hyperosmolal contents. The process of dilution followed a simple dilution curve. At the same time hemoconcentration and increased serum osmolality reflected the mobilization of fluids from the extravascular and vascular compartments. The transfer of fluids into the intestinal lumen continued throughout the test period, despite the fact that there was a linear increase in intraluminal pressure to a relatively high level, indicating increased smooth muscle tone probably due to the hyperosmolal provocation. The observed accumulation of fluid was well reproducible and associated with predictable effects on the vascular and extra-vascular compartments.

Animals↗
PubMed1978

Experimental studies on fluid pathophysiology in small intestinal obstruction in the rat. II. Effects of intraluminal hyperosmolality and simultaneous intravenous infusions.

Using an experimental model in rats a hyperosmolal glucose solution was introduced into the intestinal lumen to simulate and magnify the accumulation of fluid seen in simple small intestinal obstruction. Efforts to modify the extent and rate of this fluid flux by administering parenteral solutions of varying osmolality produced no result. When hypoosmolal or iso-osmolal infusion solutions were used, the intraluminal dilution process displayed mathematical characteristics in agreement with those of a simple dilution process, while at the same time normal blood volume was maintained. On the other hand, when a hyperosmolal glucose solution was infused, very great demands were made on the extravascular compartment, because a severe diuresis equal in volume to the fluid given parenterally took place, while at the same time there was marked hemodilution. Despite this the organism delivered as much fluid to the intestine as when hypo-osmolal or iso-osmolal infusions were given. Thus in principle the flow of fluid into the intestinal lumen could not be modified by giving parenteral solutions of any osmolality.

Animals↗
PubMed1978

Experimental studies on fluid pathophysiology in small intestinal obstruction in the rat. IV. Effects of intraluminal hyperosmolality and simultaneous intravenous infusions on mucosal micromorphology.

A hyperosmolal glucose solution was introduced into a loop of small intestine of specified length and position while intravenous infusions of varying osmolality were given at the same time. The hyperosmolal solution in the lumen caused damage primarily to the tips of the villi where sloughing of the epithelial cells was frequently seen. These defects were repaired by an increase in surface coverage by neighboring epithelial cells, which thus were reduced in height. A varying degree of edema was generally seen in the epithelial cells. The severity of these lesions was modified by intravenous infusions in inverse relationship to the osmolality of the infusions. Thus the defence mounted by the intestinal mucosa against the hyperosmolal solution in the lumen was impaired by the infusion of hypo-osmolal solutions and improved by hyperosmolal solutions. In the latter cases the mucosa maintained a practically normal histological picture.

Animals↗
PubMed1978

Experimental studies on fluid pathophysiology in small intestinal obstruction in the rat. III. Effects of intraluminal iso-osmolality and simultaneous intravenous infusions.

The introduction of a hyperosmolal glucose solution in the intestinal lumen in an experimental model using rats resulted in the accumulation of large quantities of fluid in the lumen, resembling the situation in simple obstruction of the small intestine. To establish whether the osmotic strength of the glucose solution caused this influx of fluid, or whether the volume of the fluid per se is a contributory factor, an identical amount of an iso-osmolal and largely non-resorbable substance was introduced in place of the hyperosmolal glucose solution. No influx of fluid into the intestinal lumen could be demonstrated even when large infusions of varying osmolality were given intravenously. The osmolality of the intestinal contents remained unchanged as well as the intraluminal pressure. Despite the massive infusion of fluids, the hematocrit remained relatively stable, thus indicating stable blood volume and demonstrating the enormous storage capacity of the extravascular compartment.

Animals↗
PubMed1978

Experimental studies on fluid pathophysiology in small intestinal obstruction in the rat. V. Effects of intraluminal hyperosmolality and simultaneous intravenous infusions on the experimentally obstructed and decompressed small intestine.

An influx of fluid into the lumen of the intestine similar to that seen in simple obstructional ileus may be provoked by introducing a hyperosmolal glucose solution into the bowel. In the otherwise intact small intestine the effect of this influx of fluid will be in accordance with a simple dilution curve. The intestinal mucosa thus functions in the manner of a semipermeable membrane permitting only hypo-osmolal fluids to enter the intestinal lumen and in amounts independent of parenteral fluid infusions, regardless of osmolality. This relationship persists even after the intestine has been totally obstructed for 3 days. The influx of fluid has the same principal characteristics, and the only limiting factor on the magnitude of this fluid shift to the intestine is the lack of fluids resulting from the marked dehydration of the organism due to ileus. Prerequisites for this are normal epithelial function and normal mucosal circulation. Thus it is clear that the organism in general and the small intestine in particular, even when exposed to prolonged obstruction, are still able to counteract intraluminal hyperosmolality by dilution with hypo-osmolal fluid.

Animals↗
PubMed1978

Adrenocortical response to ACTH stimulation in postmature newborns.

Diminished total plasma cortisol levels have been demonstrated in postmature neonates, suggesting that fetal glucocorticoids may be involved in the cause of postmaturity. This hypothesis was tested by adrenocortical stimulation in 32 newborns: 12 were postmature; 12 were postterm, but not postmature; and 8 were normal term neonates. The mean pre- and poststimulation total plasma cortisol levels were 3.9 and 50.9 microgram/100 ml, respectively, for the postmature newborns, 9.7 and 44.0 microgram/100 ml for the postterm, but nonpostmature newborns, and 9.8 and 37.1 microgram/100 ml for the normal term newborns. The differences in the poststimulation rise in plasma cortisol between the postmature and merely postterm infants or between the postterm and normal term infants were not statistically significant. The mean poststimulation cortisol rise in the postmature group exceeded that of the normal term group (P less than 0.05). The adequacy and promptness of response to adrenocortical stimulation eliminate the likelihood of adrenal insufficiency in postmature infants.

Adrenal Cortex↗
PubMed1978

Preliminary results of combined surgery and adjuvant Bacillus Calmette-Guérin plus levamisole treatment of resectable lung cancer.

The administration of intrapleural bacillus Calmette-Guérin (BCG) alone and intrapleural BCG plus levamisole was compared to placebo in patients with resectable, non-small cell cancer of the lung. This report is based on an interim analysis of 100 eligible patients with a median followup of 245 days. No significant treatment effects are apparent at the present time, although current trends are consistent with an approximate 30% reduction in recurrence rate in patients receiving intrapleural BCG. There is little evidence to suggest that the addition of levamisole will contribute to this effect. A relationship between purified protein derivative conversion and tumor recurrence is apparent. Failure to manifest purified protein derivative conversion following administration of intrapleural BCG is associated with a significantly greater risk of tumor recurrence.

Adenocarcinoma↗
PubMed1978

Scanning electrons and light microscopy of the equine seminiferous tubule.

Changes within the equine seminiferous tubules during the cycle of the seminiferous epithelium were studied light and scanning electron microscopy (SEM). Once observed with SEM, tubules were sectioned and staged using light microscopy. As viewed by SEM, the weblike, spongy cytoplasm of germ cells or Sertoli cells in stages I and II extended over the entire height of the germinal epithelium. The cytoplasm of the basal portion of the germinal epithelium in stages III to VIII was similar to that in stages I and II. However, the cytoplasm which occupied the luminal third of the epithelium in stages III to VII was smooth appearance. The smooth-surfaced, periluminal cytoplasm diminished in stages VIII. Principal pieces of flagella from spermatids extended into the tubular lumina in all stages whereas the middle pieces extended into the lumen only in stage VIII. Later in stage VIII, the middle pieces, which were thickened with cytoplasm, were connected to the germinal epithelium by stalks. After spermiation, the diameter of the middle pieces was similar to that of ejaculated spermatozoa. Thus, the cytoplasm within the thickened middle pieces contributed to the formation of the cytoplasmic droplets.

Animals↗
PubMed1977

The use of paratenon, polyethylene film, or silastic sheeting to prevent restricting adhesions to tendons in the hand.

We treated 132 patients by insertion of paratenon, polyethylene, or Silastic between a digital tendon and a bone, ligament, or fixed fascial structure to prevent adhesions. From 1950 to 1974, autogenous paratenon was used in thirty patients; from 1956 to 1965, polyethylene film was used in sixty-three patients; and from 1965 to 1974, Silastic sheeting was used in thirty-nine patients. By comparing the preoperative and postoperative measurements of joint motion and the changes in the distance separating the pulp of a finger from the palm during flexion, these patients were calssified as improved, unchanged, or worse. In some areas the material used appeared to make little difference, but in other areas one or the other was superior. Silastic sheeting (non-reinforced) proved to be the best material for most conditions, but it should not be employed when the skin is of poor quality or beneath a pedicle flap, and it should not be used adjacent to a tendon graft in an area that has recovered from an infection. Under those circumstances, paratenon is the preferred material.

Adipose Tissue↗
PubMed1976

The synthesis of connective tissue protein in smooth muscle cells.

The synthesis of elastin by smooth muscle cells was clearly demonstrated by amino acid analyses and the presence of lysine-derived crosslinks. The values obtained were compatible with those found in amorphous elastin isolated from rabbit aortic tissue. Collagen synthesis by these same cells was monitored by the appearance of [14C] hydroxyproline when the cells were grown in the presence of [14C] proline. When the cells were pulsed with [14C] lysine, one could detect [14C] hydroxylysine and [14C] glucosylgalactosylhydroxylysine. Further evidence for the synthesis of elastin and collagen was the finding of radiolabelled epsilon-hydroxynorleucine and the reduced aldol condensate of two residues of allysine after reduction of [14C] lysine pulsed cells with NaBH4.

Animals↗