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Biomedical subjects

G Zajicek

Publications and source records attributed to G Zajicek.

At least 73 records · Page 4Linked to original sources
PubMed1990

Streaming liver. VII: DNA turnover in acinus zone-3.

Livers of four young, male, random-bred rats weighing 250 g were fixed in formalin and stained with Feulgen. In each section, 50 hepatocytes were randomly selected and their distance from the nearest terminal hepatic vein was measured with an eye-piece micrometer. Distance was expressed in two units: 1. micrometer and, 2. cell location, or the cell number separating a sampled cell from the terminal hepatic rim. The sections were scanned with an image cytometer. The tissue was magnified x 400 and digitized into 512 x 512 pixels. The software determined the nuclear boundary and estimated its area and optical absorbance, which was expressed in relative DNA units. One unit equals the absorbance of a diploid lymphocyte. Nuclear area and optical absorbance measurements were made up to 220 microns distance from the terminal hepatic vein which roughly covers zones 2 and 3. Previously we have shown that in zones 1 and 2 hepatocyte nucleus enlarges and becomes polyploid. The present study demonstrates that in zone-3 this trend is reversed, nuclear area and DNA absorbance decline. The average hepatocyte advances 2 microns daily. In zone-1 it accumulates daily 0.005 DNA absorbance units and in zone-3 it loses daily 0.24 DNA absorbance units. It is proposed that in zone-3 DNA leaves the intact cell in a physiological way. DNA accumulation and polyploid are regarded here as forms of gene amplification which may be reversed, so that under these circumstances amplified DNA may be "deamplified" and the excess DNA leaves the cell.

Animals↗
PubMed1990

Streaming liver. VI: Streaming intra-hepatic bile ducts.

Thirty male adult rats, weighing 250-300 g, were injected with 0.5 muCi [3H]-thymidine. The rats were killed in groups of five, at the following times: 1 h, 14, 30, 60, 90 and 120 days. The livers were fixed in formalin, embedded in paraffin and cut into 5-microns-thick sections, which were then dipped into liquid emulsion for autoradiography. Bile ducts were evaluated in all portal tracts of a section. Obliquely cut bile ducts were excluded. The number of cells paving the duct lumen was defined as bile duct class. Class is roughly proportional to bile duct size. One hour after labelling, labelling index was 3.39 +/- 0.06% (the second number is one standard error of the mean). With time it declined, reaching 0.22 +/- 0.15 on day 60. Initially labelled cells were found in narrow bile ducts and the mean labelled cell was located at class 7.48 +/- 0.63. With time, labelled cells proceeded into wider bile ducts advancing daily 0.122 +/- 0.025 classes. Intra-hepatic bile duct epithelium renews its cells continuously in the same way as epidermis or gastro-intestinal mucosa do. It consists of two kinetic compartments, a progenitor (P) and a functional (Q) compartment. P feeds Q with cells.

Animals↗
PubMed1990

Cell kinetics of normal adult hamster bronchial epithelium in the steady state.

To establish the progenitor role of bronchial epithelial cells in the steady state, we undertook a quantitative autoradiographic study in normal hamsters. Groups of 7 hamsters were killed 1 h and 1, 2, 3, 4, 7, and 14 d after an intraperitoneal injection of [3H]thymidine (2 microCi/g body wt). Autoradiograms were prepared from 861 Epon sections, 2 microns thick, of left intrapulmonary hilar bronchi. Epithelial cells were classified into 1 of 7 categories: basal-1 (B1) and basal-2 (B2), depending on nuclear height; secretory cells denoted as S1 with zero to 4 granules, S2 with 5 or more granules with intervening cytoplasm, and S3 with abundant granules completely filling the cytoplasm; ciliated (C); and indeterminate (IN). Mean silver grain counts decreased significantly over time only for B1 cells (P less than 0.05), with a cell cycle time of 20.6 d and a DNA synthetic time of 7.5 h. Labeled cells, 1 h after thymidine injection, comprised 30.5% S1, 27.8% B1, 22.8% B2, 6.8% IN, 6.4% S2, 5.7% C, and 0% S3 cells. Labeling indices of individual cell categories (LIc), at 1 h after labeling, were highest for B1 followed by B2 cells, reflecting their proliferative intensity. Labeling index of all epithelial cells combined did not change with time, indicating that there was no major cell death or label dilution. The LIc decreased significantly over time only for B1 and B2 cells (P less than 0.001 and P less than 0.002, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Streaming pancreas: islet cell kinetics.

Thirty male young adult rats aged 7 weeks, weighing 200 g, were injected with 0.5 microCi/g body weight tritiated thymidine (specific activity 5.0 Ci/mM). The rats were then killed in groups of five, at the following times: 1 hour, and 14, 28, 42, 56, 90, and 120 days. The pancreata were dissected, embedded in paraffin, and cut into 5 microns thick sections which were then dipped into liquid emulsion. The labelling index of acini and islet cells was estimated in each autoradiogram, and their distance from intercalated duct was measured. Acini and islet cells streamed away from the intercalated duct at a daily velocity of 0.52 microns. Acinus labelling index which was initially 0.78% declined with time. Islet cell labelling index was initially 0.38%. In the following days it climbed upward reaching on the 42nd day its peak value of 0.78%. From then onward it declined to a low of 0.38%. Since cells were labelled only once, and labelling was instantaneous, it is concluded that labelled acinus cells entered the islet, and that acinus cells are actually islet cell precursors. The pancreas is structured kinetically like other exocrine glands, being a two compartment cell renewal system which continuously renews its cells. The pancreocyte is a descendant of an intercalated duct progenitor. After leaving the duct it turns into an acinus cell, gradually approaching the Langerhans islet. After crossing its border it becomes an islet cell, and proceeds toward the islet center. Its population size dwindles exponentially until at islet center all cells are eliminated.

Animals↗
PubMed1989

A double staining method for measuring DNA content of specific cell populations utilizing computerized microscopy.

A method for identifying specific cell populations with the computerized microscope is described. This method utilizes double staining techniques using immunofluorescent antibodies and the Feulgen technique. It was applied to measure the area and DNA content of the nuclei of beta-cells in patients with Persistent Neonatal Hypoglycemia with Hyperinsulinism (PNHH). A significant increase in the area and DNA content was found in nuclei of patients compared to a control group. This method may be applied to sample cells from other tissues as well.

Coloring Agents↗
PubMed1989

Diagnosis deferred--the clinical spectrum of diagnostic uncertainty.

This study attempts to define the term "Diagnosis Deferred" (DD) and determine its natural history and outcome. It is suggested that such a "non-diagnosis" should be used when the clinical and laboratory picture cannot be explained by any known disease entity after a minimum of 5 days hospitalization. During a 9 year period (1972-1980) 250 patients (1.8%) were identified as warranting the term DD from a total of 14,098 admissions to a department of Internal Medicine. Their average stay in hospital was 11.5 days. There was no sex difference between the patients, whose average age was 42.8 +/- 17.6 years (mean +/- SD; range 14-93). Three complaints predominated: joint pains (21.6%), abdominal pain (20.4%) and chest pain (16.8%). In 103 of the patients, there was follow-up information until the diagnosis was made or for at least 24 months (average 53.0 +/- 40.0 months, range 2-186). These patients were representative of the original cohort in both age, sex and classification of symptoms. Forty-three patients (42%) were subsequently diagnosed. 58% of these patients were diagnosed as a result of a change in or appearance of a clinical symptom during the follow-up period. "The survival of diagnostic uncertainty" in 50% of the patients was 84.5 months (7 years) with a range of 2-13 years. This time was significantly shorter for chest pain than for abdominal pain (33 months vs 87 months) (p = 0.003). In patients with "Diagnosis Deferred", a diagnosis was reached in 42%; in 22% the symptoms disappeared leaving 36% undiagnosed, and a continuing clinical challenge.

Abdomen, Acute↗
PubMed1989

The streaming of the submandibular gland. II: Parenchyma and stroma advance at the same velocity.

Thirty young male rats aged 7 weeks, weighing 200 g, were injected with 18.5 kBq g-1 (0.5 microCi g-1) body weight tritiated thymidine [3H]TdR (specific activity 185 GBq). The rats were then killed in groups of five, at the following times: 1 hour, and 14, 30, 60, 90, and 120 days. Autoradiograms of sections through the submandibular gland were prepared, and the location of labelled cells in tubular and acinar cross sections was recorded. The nuclear content of each cross section was defined as its 'class'. In this numbering system, narrow tubuli, e.g. intercalated ducts are of low class, and wider tubuli, e.g. striated ducts, of high class. One hour after labelling most labelled tubular cells were found in low class cross sections, i.e. intercalated ducts and narrow granular ducts. Striated ducts were not labelled. From then onward labelled cells entered wider tubuli, e.g. striated ducts. The advancing labelled epithelium was accompanied by labelled stroma. Both cell types traversed 0.089 classes per day. In acini, labelled cells advanced in the opposite direction, starting from acinar cross sections of high class and ending in class-1 cross sections.

Animals↗
PubMed1989

The streaming liver IV: DNA content of the hepatocyte increases with its age.

Hepatocyte age was estimated from its distance from the portal tract. We have previously shown that hepatocytes are formed adjacent to the portal tract and stream toward the terminal hepatic vein, advancing at a daily velocity of 2 microns. Thus, the farther a cell from the portal tract, the older it is. This relationship between cell age and distance served here for the study of age-dependent changes in the hepatocyte, particularly nuclear area and DNA content. DNA content was derived from the absorbance of Feulgen-stained nuclei in 5-microns-thick tissue sections. Absorbance and nuclear area were measured with a cytophotometer. Since most nuclei of the tissue section were sliced, DNA content was estimated also in intact nuclei which were sampled by fine needle aspiration, and stained with either Feulgen or propidium iodide. Feulgen-stained nuclei were scanned by a cytophotometer, while the DNA content of propidium iodide-stained nuclei was measured by flow cytometry. Absorbance was expressed in relationship to the mean absorbance of diploid periportal littoral cells. Littoral absorbance was defined as one absorbance unit. A high correlation between nuclear absorbance and area was observed in nuclear suspensions (adjusted r-square 0.79), so that nuclear area may serve as a good predictor of nuclear DNA content, which is valuable in routine sections which are stained with H and E. Most periportal hepatocytes were polyploid and their mean absorbance was 1.68 units. Nuclear absorbance increased with cell distance from the portal tract. Within 100 microns it rose from 1.68 to 1.92 units. Nuclear area increased by 13%.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

The streaming liver. V: Time and age-dependent changes of hepatocyte DNA content, following partial hepatectomy.

Two processes contribute to the change in hepatocyte ploidy following partial hepatectomy: one is age-dependent, while the other depends on the time which has elapsed since hepatectomy. While in the normal liver hepatocyte DNA content increases with the age of the cell, following hepatectomy the average DNA content (or ploidy) for the entire population rises as well. Hepatocyte age was derived from the cell's distance from the portal tract. We have previously shown that hepatocytes are formed adjacent to the portal tract and stream toward the terminal hepatic vein, advancing 2 microns/day. This finding enables the estimation of hepatocyte age from its location, since the older a cell the more remote it is from the portal tract. Twenty-four young male random-bred rats were partially hepatectomized and killed in groups of four animals at the following times: 1 h and 1, 2, 3, 7 and 14 days. Liver sections and nuclear suspensions which were collected by fine needle aspiration were stained with Feulgen and measured with the aid of computerized image cytometry. Part of the suspension which was aspirated with a fine needle was stained with propidium iodide and measured by flow cytometry. Both nuclear area and the DNA content increase with the age of the cell. The older a cell, the higher its ploidy. Generally, young hepatocytes which synthesized DNA did also divide, while older cells tended to accumulate DNA and became polyploid. The average nuclear DNA content of the entire population increased by 14% in 3 days.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Effect of chronic misoprostol ingestion on rat gastric morphology and cell turnover.

The effect of long-term misoprostol - a synthetic prostaglandin E1 analogue - ingestion on rat gastric morphology and cell turnover was studied. Misoprostol in a daily dose of 90 micrograms/kg or 9,000 micrograms/kg was intragastrically administered to rats. Control rats were treated with the vehicle only. Following 90 days of treatment, 3H thymidine was injected i.v. and rats were sacrificed 1 h later. Tissue sections were prepared from the stomach body and subjected to autoradiography. Misoprostol treatment significantly reduced body weight gain. High dose misoprostol treatment induced significant increases in gastric wall thickness and in gastric gland length. On the other hand, the labelling index was significantly reduced by treatment with high dose misoprostol. These results indicate that chronic administration of misoprostol in high doses increases gastric wall thickness and decreases gastric cell turnover, suggesting that administration of prostanoids causes an increase in cell survival and a decrease in cell shedding.

Alprostadil↗
PubMed1988

Nesidiodysplasia--a histologic entity?

Five cases of persistent neonatal hyperinsulinemic hypoglycemia (PNHH) were studied by a combined immunofluorescent and Feulgen technique under a computerized microscope which was used to measure the area and absorbance of beta cell nuclei. An increase of 16% was found in the nuclear area and absorbance of the beta cells in PNHH cases, in comparison with age-matched control cases. A smaller increase (9%) was found in nuclear area and absorbance of non-endocrine ductal cells in PNHH cases. In all PNHH and control cases, higher values of nuclear area and absorbance were found for beta cells in the islets of Langerhans than for nesidioblasts. The increase in average size of beta cell nuclei in PNHH can be used as a morphologic criterion for diagnosis in these cases. The increased absorbance of the nuclei stained with the Feulgen reaction is the morphologic expression of polyploidy, and has a correlation to the metabolic activity of beta cells in this disorder. We conclude that, in contrast to the normal postnatal developmental process of nesidioblastosis, nesidiodysplasia is a well-defined histologic entity, manifested by an increase of beta cell nuclear size and its DNA content.

Humans↗
PubMed1988

The streaming liver. II. Hepatocyte life history.

Thirty male adult rats, were injected with [3H]-thymidine, [3H]TdR. The animals were killed in groups of five, at the following times: 1 h, 14, 30, 60, 90 and 120 days. The livers were fixed in formalin, embedded in paraffin and cut into 5-micron-thick sections, which were then dipped into liquid emulsion and exposed for 3 weeks. The grain content of each sampled cell was counted and its distance from the nearest portal tract rim measured. Since the cells were labelled once and the label was available only for a short period, cell displacement could be followed with time. One hour after labelling, most labelled cells were confined within the 300 micron distance from the portal space rim. From then on, labelled cells advanced at a daily velocity of 2.5 micron toward the terminal hepatic vein. The liver acinus is composed of two compartments: a progenitor compartment extending up to 300 micron from the portal tract and a functional compartment covering the remaining acinus portion. Such an arrangement is known as a two-compartment cell renewal system, and is found in renewing tissues like crypt-villus and epidermis. The hepatocyte moves from the portal space toward the terminal hepatic vein, proceeding along a trajectory, denominated as tissue radius. Since cells move in one direction, the further a cell is from the portal tract, the older it is. One may therefore estimate cell age by measuring its distance from the origin. Since the tissue radius portrays cells of all ages, it describes the entire life history of one cell. The advancing hepatocytes traverse the three acinus zones.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

The streaming liver. III. Littoral cells accompany the streaming hepatocyte.

In previous studies we have shown that hepatocytes stream from the portal tract toward the terminal hepatic vein. The present study provides evidence that littoral cells participate in the same cell stream and that the liver actually streams en masse. Littoral cells stand for sinusoidal endothelia and Kupffer cells. Thirty male adult rats, random bred, were injected with 0.5 microCi [3H]-thymidine, specific activity 5 Ci/mmol/g body weight. The rats were killed in groups of five, at the following times: 1 h, 14, 30, 60, 90 and 120 days. The livers were processed histologically and dipped into liquid emulsion for autoradiography. In each animal 50 labelled hepatocytes and 50 littoral cells were randomly selected and their distance from the nearest terminal portal tract rim was measured. Both cell populations renew their cells continuously. Each consists of two cell types, progenitors, residing around the portal tract up to the distance of 200 microns, and functional cells, which inhabit the rest of the acinus. The two regions where the different cell types reside are known respectively as progenitor (P) and functional (Q) compartments. Both cells are formed in the P-compartment and advance jointly along a trajectory, the tissue radius, toward the terminal hepatic vein where they die. They progress at a daily velocity of 2 micron. Since both advance at the same speed, as long as they exist they remain neighbours. Liver parenchyma and stroma thus stream en masse.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

The rat parotid gland--a renewing cell population.

The mode of turnover and displacement of cells in the rat parotid gland was studied by means of autoradiography. The parotid parenchyma and stroma act as a two-compartment cell renewal system. Parotid cell progenitors are formed mainly in the intercalated duct from which they progress in opposite directions: to the striated duct on one side, while feeding into the acini on the other. The stroma cells stream along the same tissue radii as the parenchymal cells.

Animals↗
PubMed1987

Growth rate analysis of lung metastases from histologically benign giant cell tumor of bone.

A growth rate analysis of lung metastases of benign giant cell tumor (GCT) of bone, histologically indistinguishable from the primary benign tumor, is presented. The doubling time (DT) was 186 days in the first 13 months of growth, and 465 days in the last 4 months. These DTs are much longer than DT of lung metastases of any other tumors, and have a good correlation with a long survival time. Backward extrapolation showed that the lung metastases began to develop years before the primary tumor was diagnosed and treated. If this can be confirmed in a larger number of patients, it could be concluded that there will be no indication for amputation as a treatment for benign GCT whether or not lung metastases are present. The growth rate analysis supports the concept that these metastases might represent a benign process, and as such are a unique histologic and clinical phenomenon.

Adult↗
PubMed1986

The application of kinematic equations for the study of cell turnover.

Cell turnover in renewing populations is accompanied by cell displacement from a site where cells are formed to a location where they are eliminated. Cell displacement reflects genuine streaming, proceeding along a trajectory denominated as tissue radius. In the sagittally sectioned gastro-intestinal crypt the radius extends along one of its cell columns. In each column the cell locations are numbered so that the crypt origin resides at location 1. Since the cell proceeds from the first location and outward, given two locations i and j such that j greater than i, the cell at j is older or more differentiated than the cell at location i, or more generally, state j represents the future state of i while state i represents a past stage for j. Cell displacement on the radius depends solely upon cell production and the acceleration of a cell through location i equals the cell production rate there. Its velocity may be represented by kinematic equations which in the present context acquire dual meaning: either describing cell displacement, or cell production associated with cell displacement. Cell velocities may be derived by following a labelled cell with time or from density distributions of labelled cells along the tissue radius. The first approach is essentially kinematic, while the second regards the density distribution as an analog of mechanical work and since work involves displacement, velocity (and cell production) is derivable from the density distribution. The two estimates are denominated here as time and space estimates. The second approach is essentially morphological, and may be applied during routine examination of histopathological slide and even be computerized.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗