Biomedical subjects

V H Gattone

Publications and source records attributed to V H Gattone.

At least 55 records · Page 3Linked to original sources

PubMed1990

Defective epidermal growth factor gene expression in mice with polycystic kidney disease.

The C57BL/6J-cpk mouse has an inheritable form of polycystic kidney disease similar to the autosomal recessive disorder seen in humans. Between approximately 1 and 3 weeks of age, affected cpk mice develop numerous large cysts in the collecting tubule segment of kidney nephrons. The present study examined the ontogeny of renal and submandibular gland prepro-epidermal growth factor (preproEGF) gene expression in the cpk mouse using Northern blot hybridization and immunohistochemistry. There was a virtual absence of renal preproEGF gene expression in cystic kidneys over the 3-week postnatal period, during which time renal preproEGF mRNA and proEGF/EGF protein normally reach significant levels. PreproEGF mRNA was expressed in salivary glands of cystic mice; however, this mRNA could not be further elevated with testosterone suggesting that there are abnormalities in the regulation of the preproEGF gene in the submandibular gland, as well as in the kidney. Since renal preproEGF expression during the early postnatal period occurs when collecting duct cysts form, it is possible that a deficiency in renal proEGF or EGF contributes to the rapid development of collecting duct cysts and the concomitant renal failure in the C57BL/6J-cpk cystic mouse.

Animals↗

PubMed1990

Developing renal innervation in the spontaneously hypertensive rat: evidence for a role of the sympathetic nervous system in renal damage.

The spontaneously hypertensive rat (SHR) exhibits increased renal sympathetic nerve activity and neurotransmitter levels compared with the control Wistar-Kyoto rat (WKY). These renal nerve abnormalities have been implicated as the cause of hypertension in the SHR. The aims of the present study were to characterize the ontogeny of renal sympathetic innervation in SHR in order to determine any functional implications. Glyoxylic acid histofluorescent and radio-enzymatic norepinephrine assays demonstrated an accelerated development of renal innervation in newborn and 1-, 2-, 3- and 6-week-old SHR compared with WKY. Sympathetic nervous system function was blocked in developing male SHR by treating pups from days 0 to 14 with: (1) guanethidine, (2) combined alpha- and beta-receptor antagonists (prazosin and timolol), or (3) vehicle (5% sucrose). Blood pressure (mean), renal function (plasma creatinine) and histologic renal damage were assessed at 42 weeks of age. Although the blood pressure of the drug-treated rats remained elevated, renal damage was reduced and renal function was improved compared with control (sucrose-treated) SHR. The data demonstrate that the SHR kidney develops a precocious sympathetic innervation and that inhibition of the development of sympathetic function ameliorates renal damage independently of systemic hypertension.

Animals↗

PubMed1990

Vasculature of the paraphysis cerebri of the frog.

The paraphysis cerebri is a glandular structure found in the third ventricle of lower vertebrates. It is well-developed in amphibians and reptiles. The function of the gland is not substantiated, but may play a role in calcium metabolism. To further elucidate its possible endocrine role, the paraphyseal vasculature was examined using casting techniques as well as transmission electron microscopy. Perfusion-fixed paraphyses of Rana pipiens and Rana catesbeiana were either: a) cast with Microfil (with subsequent dehydration, clearing, and macroscopic examination) or Batson's compound (followed by tissue digestion and examination by scanning electron microscopy); or b) processed for transmission electron microscopy. The paraphyseal capillary bed consists of a sinusoidal portal system which receives afferent blood from its associated choroid plexus. The choroid plexus of the third ventricle receives its blood supply via arterioles from the posterior telencephalic artery. These arterioles traverse in the periphery of the paraphysis to branch and supply the choroid plexus. Numerous venules exit from the choroid plexus and drain into sinusoids of the paraphysis. The sinusoid venules appear to empty into a midline venous structure which passes tangentially through the paraphysis. The sinusoids consist of fenestrated endothelium which is indicative of transport vessels. Nerve fibers were observed in the paraphysis, however, histofluorescence revealed no monoaminergic sympathetic innervation of the paraphyseal vasculature.

Animals↗

PubMed1989

Atrial natriuretic peptide in heart and specific binding in organs from fetal and newborn rats.

To assess the possibility that atrial natriuretic peptide plays a role in salt and water balance during early mammalian development, we examined hearts from fetal and neonatal rates for the presence of this peptide and presumed target tissues for their ability to bind the hormone. Immunohistochemistry was used to localize and radioimmunoassay to quantify this peptide in heart. Immunoreactive atrial natriuretic peptide was visualized in the fetal heart on day 17.5 post-conception. It was distributed throughout the atrial appendages and free wall and, in ventricle, in the trabeculae carnae and chordae tendineae. The concentrations of immunoreactive atrial natriuretic peptide in atria of rats on day 19.5 post-conception were one-tenth of those in the adult. Levels of this peptide in fetal ventricle were low and virtually absent from the adult tissue. Specific binding of radiolabelled atrial natriuretic peptide measured by whole organ counting occurred in several organs from 19.5-day fetal and neonatal rats. A number of these tissues, including the kidney, ileum, adrenal, lung and liver, are targets for and/or bind the peptide in adult rats. Specific binding in these tissues was localized using autoradiography at anatomical sites similar to those in adult organs. Specific binding was also seen in fetal but not neonatal skin. In the kidney, binding was associated with immature as well as mature glomeruli. These findings support the proposition that atrial natriuretic peptide may function in the perinatal rat as it does in the adult and, in addition, may play a unique role during fetal life.

Adrenal Glands↗

PubMed1989

The effect of glutathione content on renal function following warm ischemia.

Reperfusion after ischemia produces tissue injury due to free radicals generated during the reflow period. Glutathione (GSH) mediates against this oxidant damage by scavenging free radicals and protecting cells against injury. In an attempt to reduce the injury caused by free radicals, rat kidneys were pretreated with GSH monoethyl ester to elevate renal GSH fivefold. Previous studies in a renal artery occlusion model showed that pretreated kidneys in comparison to untreated controls were functionally impaired as measured by glomerular filtration rate, urine flow rate, and histology. To eliminate systemic effects of the pretreatment, kidneys were subjected to a fixed period of warm ischemia but flushed of blood and transplanted into nonpretreated syngeneic recipients. As before, pretreated kidneys exhibited marked functional impairment. We conclude that (i) elevation of renal GSH with GSH monoethyl ester enhances rather than prevents renal dysfunction and (ii) the enhancement of renal ischemic injury following pretreatment is not due to nonspecific systemic effects of GSH monoethyl ester pretreatment.

Animals↗

PubMed1989

Correlation of structure and function in developing proximal tubule of guinea pig.

Unlike the case in rat, rabbit, and other species in which nephron formation continues into the newborn period, nephrogenesis in the guinea pig is completed well before the time of birth. Therefore, the marked increase in proximal tubule reabsorption that occurs during the postnatal period in that species can be attributed entirely to an increase in the absorptive capacity of existing nephron units. The purpose of the present morphometric studies was to correlate that change in proximal tubule function with changes in the apical and basolateral cell membrane surface areas. The apical and basolateral membrane surface densities were found to be approximately equal to each other and to remain constant throughout development. Because of increasing tubule volume, however, both membranes doubled in size between 1 and 3 wk of age and eventually increased by a factor of 3.5 in the adult. At the same time, there was little change in the length of tight function complexes measured in the plane of the luminal surface. Using previously published functional data and tubule length data, a good correlation was found between absolute absorption and total basolateral membrane surface area throughout the entire period of development in proximal tubules. Absorption per unit area of basolateral membrane was approximately 0.55, 0.41, 0.56, and 0.42 X 10(-6) nl.min-1.micron-2 in the 1st, 2nd, and 3rd wk, and in adult animals, respectively, and thus was similar to that reported for proximal tubule segments of adult rabbit and juvenile to adult rat.

Absorption↗

PubMed1988

Postnatal maturation of the rabbit cortical collecting duct.

The mature, fully differentiated cortical collecting duct plays a major role in the final renal regulation of Na+, K+ and H+ transport. To characterize the growth of this segment, we measured the outer diameter and the dry weight of cortical collecting ducts isolated from newborn, 1-month-old, and adult rabbits. During the 1st month of life no significant changes were observed; however, there was a 60% increase in both parameters after the 4th week of life. Growth-related accretion of K+ was demonstrated by showing tubular K+ content to increase by 60% with maturation. Concomitant with the increase in tubular size, total cell number per millimeter of tubular length rose by 30%. Approximately 50% of the observed increment in tubular size could be accounted for by cell hyperplasia, with the remaining increase resulting from cell hypertrophy. Hypertrophy of principal cells was confirmed by scanning electron microscopy, which demonstrated a doubling of the circumferential width without any change in longitudinal length. Hyperplasia was confirmed, using a fluorescent chromatin stain, by our finding of a mitotic frequency of 3/1000 cells in the neonatal mid-cortical collecting duct; the observed number of mitoses was 10-fold higher at the most cortical end (ampulla). The number of intercalated cells per millimeter of tubule length, identified by bright green fluorescence after cortical collecting ducts were stained with 6-carboxyfluorescein diacetate, was found to double during maturation, the increase being significant only after the 4th postnatal week. We conclude that maturation of the mid-cortical collecting duct results from both cellular hyperplasia and hypertrophy. It is unlikely that this segment plays a major role in regulating Na+, K+, and H+ transport in the neonatal kidney.

Animals↗

PubMed1988

Effect of an altered glutathione content on renal ischemic injury.

Renal ischemia and reperfusion have been shown to be associated with an enhanced renal lipid peroxidation. Because glutathione (GSH) serves to protect cells from oxidative stress, the role of GSH in renal ischemia was investigated. The content of renal GSH in the rat declined to 40% of control values during 35 min of renal artery occlusion. Renal GSH levels only partially recovered after 120 min of blood reflow. To assess the significance of this effect, renal GSH levels were altered before occlusion of the renal artery. Rats were treated with either buthionine sulfoximine (BSO) or glutathione monoethylester (GSH-ester) to lower or elevate, respectively, renal GSH levels. The ischemia-induced changes in renal ATP, ADP, and AMP after 35 min of ischemia and 90 min of blood reflow were not affected by prior alteration of renal GSH levels. The ischemia-induced decrease in the respiratory control of isolated cortex mitochondria was also unaffected. In control animals, ischemia of 35 min increased urine flow rate 3.2-fold and decreased GFR to 29% of normal values during the reflow period. Similar changes occurred in kidneys with a depleted GSH level. In kidneys with an elevated GSH, however, both urine flow rate and GFR were decreased to values 50 and 3% of normal, respectively. Morphological analysis demonstrated that ischemia produced an enhanced degree of damage with an increase in cast formation in kidneys pretreated with GSH-ester; however, the ester also produced morphological changes in nonischemic kidneys. The severity of ischemic damage was similar in kidneys with a lower GSH content when compared with controls. We conclude that renal GSH is depleted by ischemia but depletion of renal GSH with BSO before ischemia has no effect on ischemic-induced damage to the kidney. However, ischemic-induced renal dysfunction is enhanced when GSH is elevated with glutathione monoethylester before ischemia.

Adenine Nucleotides↗

PubMed1988

Autosomal recessive polycystic kidney disease in a murine model. A gross and microscopic description.

The C57BL/6J-cpk genetic murine model of autosomal recessive polycystic kidney disease was examined to gain insight into the pathogenesis of renal cystic disease. Fetal through 3-week-old offspring of heterozygote matings were used to study growth parameters and morphology of this genetic form of cystic disease. The kidneys were examined by light and electron microscopy and nephron segments were microdissected. Two phases of cystic disease development were morphologically identified. The first phase in fetal and newborn affected pups was characterized by proximal tubule enlargement and a general increase in the tubular mitotic index. The proximal tubules showed cytologic abnormalities along with an increased necrotic cell index. The later phase, in one through 3-week-old cystic pups, was characterized by progressive enlargement of the kidneys due mainly to cystic change of the collecting ducts and by development of azotemia. Secondary to the azotemia was a stunted body growth. Significant tubular epithelial hyperplasia was not found by mitotic index during the second phase, but an increase in collecting duct cellularity was present. Histone H4 gene expression, which is tightly coupled to DNA synthesis and thus an index of cell proliferation, showed only a minimal increase in cystic kidneys at 1, 2, and 3 weeks of age. Therefore, the degree of cell proliferation necessary to allow the observed tubular enlargement appears to be minimal.

Animals↗

PubMed1987

The effect of epidermal growth factor on neonatal incisor differentiation in the mouse.

The effect of epidermal growth factor (EGF) on cellular differentiation of the neonatal mouse mandibular incisor was examined autoradiographically using tritiated thymidine ([3H]TDR) and tritiated proline ([3H]PRO). On days 0 (day of birth), 1, and 2, EGF was administered (3 micrograms/g body wt) sc to neonates. Mice were killed on Days 1, 4, 7, 10, and 13 after birth and were injected with either [3H]TDR or [3H]PRO 1 hr before death. [3H]TDR was used to analyze cell proliferation in eight cell types in the developing mouse incisor including upper (lingual) and lower (buccal) pulpal fibroblasts, preodontoblasts, inner and outer enamel epithelial cells (IEE and OEE), stratum intermedium (SI), stellate reticulum (SR), and periodontal ligament (PDL) fibroblasts. [3H]PRO was used to analyze protein synthesis in ameloblasts, and their secretion products (enamel and dentin), as well as PDL fibroblasts. The selected EGF injection scheme elicited acceleration of incisor eruption with minimal growth retardation. At Day 1, the upper and lower pulp, preodontoblasts, SI, and SR showed a significant decrease in labeling index (LI) 24 hr after a single EGF injection. After multiple injections (Days 0, 1, 2), two LI patterns were observed. In lower pulp, preodontoblasts, IEE, SI, SR, and OEE, a posteruptive change in LI was observed. In contrast, the upper pulp and PDL regions demonstrated a direct temporal relationship with eruption. Autoradiographic analysis with [3H]PRO indicated that EGF treatment caused significant increases in grain counts per unit area in ameloblast, odontoblast, and PDL regions studied. Significant differences were found in all four regions studied (ameloblasts, enamel, odontoblasts, dentin) at the 45-microns-tall ameloblast level as well as ameloblasts and odontoblasts at the 30-microns level at 13 days of age. The PDL demonstrated significant differences at all locations studied (base, 30 microns, 45 microns,) in 4-, 7-, and 13-day-old mice. Morphologically, EGF-treated groups demonstrated premature differentiation of ameloblasts and odontoblasts at the light microscopic level. The data indicate that EGF alters DNA and protein synthesis as well as differentiation patterns during the eruption process. While EGF affects both DNA and protein synthesis, the alteration of differentiation may be secondary to mitogenic effects on proliferative compartments. In order to determine the cellular target for EGF within the newborn mouse incisor, in vivo 125I-EGF binding was analyzed autoradiographically.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed1986

Morphological evaluation of vascular smooth muscle cell: length and width from a single scanning electron micrograph of microvessels.

Accurate three-dimensional data on the structure of vascular smooth muscle cells is essential for understanding the microvascular system in both normal or disease conditions. The laborious serial reconstruction methods have limited the amount of data collected on the structure of individual vascular smooth muscle (VSM) cells. The circumferential viewing of whole vessel segments via scanning electron microscopy provides an alternative approach, but even this technique is highly specialized and tedious. This study presents a simplified method to determine the average cell length and width of individual VSM cells by using only one view of a microvessel (single view). The vessels do not have to be isolated for circumferential viewing and can be left in their host tissue if desired. Values for the average VSM cell length and width were obtained by both circumferential- and single-view approach on the same vessels. The average cell length and width obtained from the single-view method (using one-third circumference) duplicated the mean length and width measurements obtained by circumferential viewing.

Animals↗

PubMed1986

Microvascular smooth muscle cell quantitation from scanning electron microscopic preparations.

A morphometric method to analyze scanning electron micrographs (SEM) of microvascular smooth muscle cells (SMC) is validated using intestinal arterioles. Features easily obtained from these microvasculature preparations are counted (number of tapers and number of complete wraps in the central 87% of the vessel, which is one-third of the vessel's circumference) or measured (vessel diameter and vessel segment length). These data allow the determination of wraps around the values as determined by circumferential examination and quantitation of the vascular segment or an alternative SEM quantitation method (Miller et al., 1986). The method described herein provides a relatively easy way to determine microvascular SMC parameters.

Animals↗

PubMed1986

gamma-Glutamyl transpeptidase excretion in cisplatin-induced acute renal failure.

Cisplatin (cisdiamminedichloroplatinum), an important antineoplastic agent, possesses nephrotoxicity as its major side effect. A mild partially reversible nonoliguric form of acute renal failure (ARF) is generally the most common form of nephrotoxicity and occurs in experimental animals following a single dose. gamma-Glutamyl transpeptidase (gamma GT) is an enzyme with maximal activity located in the brush border of proximal renal tubular epithelium. To test the relationship between cisplatin nephrotoxicity and urinary gamma GT excretion, rats received a single 5.5 mg/kg dose of cisplatin and gamma GT excretion was evaluated and compared to anatomic and functional damage. Twenty-four hours following cisplatin administration, there was a marked enhancement of urinary gamma GT excretion, prior to the onset of azotemia. Urinary gamma GT excretion peaked at day 4, then returned to baseline, and decreased to values below baseline on days 8 through 10. By days 11 through 12, renal function and urinary gamma GT excretion had returned to normal. The correlation between nephrotoxicity, changes in urinary gamma GT excretion, and anatomic damage was excellent. Morphologically, increased gamma GT excretion was associated with loss of microvilli, and the return of urinary gamma GT excretion to normal correlated with their regeneration. We conclude that cisplatin administration results in increased urinary gamma GT excretion. This early enhancement, prior to the onset of azotemia, may provide a useful noninvasive marker of early cisplatin nephrotoxicity.

Acute Kidney Injury↗

PubMed1986

Extrinsic innervation of the rat kidney: a retrograde tracing study.

To determine the exact modalities involved in the innervation of the kidney, the present study used a nerve-tracing method with horseradish peroxidase-wheat germ agglutinin (HRP-WGA) as the tracer. Multiple injections of HRP-WGA were made in each of the left kidneys of 12 rats while another four had the HRP-WGA either dripped onto their intact renal mesothelial surface or injected intravascularly. After retrograde transport of the tracer to neurons of origin (i.e., 72-h survival), the rats were briefly perfusion fixed, tissue was removed, and cryostat sections were cut. The free-floating sections were reacted by the tetramethylbenzidine technique. Retrogradely labeled neurons were found in the celiac, bilateral inferior vagal (nodosal), and ipsilateral dorsal root (90% in T12-L1 DRG) ganglia. More labeled neurons were present in the combined vagal ganglia than in the combined DRG within each animal. This labeling was specific compared with the controls (HRP-WGA uptake via intraperitoneal or vascular routes). The celiac ganglion had many labeled neurons; however, no labeled neurons were seen in the dorsal motor nucleus of the vagus, nucleus solitarius, nucleus ambiguus, or any other brain stem structure after renal injections of HRP-WGA. This study has determined that the sympathetic nervous system (celiac ganglion) provides the only renal autonomic efferent (motor) innervation, and the nodosal (inferior vagal) ganglia appear to provide more renal sensory innervation than do the dorsal root ganglia.

Animals↗

PubMed1986

Mitochondrial alterations in cisplatin-induced acute renal failure.

The mild reversible nonoliguric form of acute renal failure is perhaps the most common of many nephrotoxic side effects that occur secondary to cisplatin administration. The present studies were undertaken to gain insight into mitochondria alterations and morphological abnormalities underlying this form of renal failure. Following a single intraperitoneal injection of 5.5 mg/kg body wt of cisplatin changes in renal function, mitochondrial respiration, and calcium accumulation were measured serially over a 9-day period. Results indicate that reversible functional changes secondary to cisplatin are accompanied by changes in mitochondrial respiration and calcium accumulation. A decline in state 3 mitochondrial respiration precedes mitochondrial calcium accumulation. However, calcium accumulation begins to recover before mitochondrial respiration. At the peak of functional and biochemical injury morphological damage is extensive, and mitochondria are strikingly aberrant. The results demonstrate that changes in mitochondrial respiration and calcium accumulation occur secondary to cisplatin administration. Both of these effects may play a role in the renal cellular injury induced by cisplatin.

Acute Kidney Injury↗

PubMed1986

Body weight of the spontaneously hypertensive rat during the suckling and weanling periods.

The body weight of the spontaneously hypertensive rat (SHR) during the suckling, birth to 3 weeks of age, and weanling period, through 6 weeks of age, is compared to that of its normotensive controls, the Wistar Kyoto (WKY) and Wistar (WR) rats. Litters were normalized to 6 pups per dam just after birth. The WR is larger than the SHR and WKY at all time points examined. The WKY is similar in weight to the SHR at birth but larger than the SHR at the other time points studied. These findings suggest the WR is inherently a larger rat than the SHR and WKY during the suckling and weanling periods while the development of a weight difference between the SHR and WKY after birth suggest an extrauterine influence.

Animals↗

PubMed1986

Quantitative renal vascular casting in nephrology research.

The present paper describes the use of a quantitative renal vascular casting method to study the changes associated with kidney disease. Several animal models of hypertension (spontaneously hypertensive rat, SHR, with its normotensive rat the Wistar Kyoto, WKY; Dahl salt sensitive DS - hypertensive, and salt resistant DR - normotensive) were examined at time points when the systemic blood pressure was rising (6 and 12 weeks of age) and following renal denervation (in SHR-WKY rats). The SHR appears to have a smaller caliber afferent arteriole at both 6 and 12 weeks of age. This difference is probably not entirely due to sympathetic vasoconstriction since the strain related afferent arteriolar diameter difference was still present after renal denervation. In the Dahl rats, there is not much of an intrarenal vascular difference between the DS and DR rats with the only real finding of a smaller distal afferent arteriolar diameter found in outer cortical nephrons of the DR. The two models of acute renal failure (ARF) that were studied include, the glycerol model (known to initially cause an intense vasoconstriction) and gentamicin, a nephrotoxic antibiotic. Two time points were examined for each of these models. As expected in the glycerol model there was an intense vasoconstriction at three hours which essentially was gone at 3 days - a time when the renal failure was fulminant. The glomerulus appeared to be contracted at three hours as well. In the gentamicin model no renal vascular alteration was seen at 6 days, when renal failure was mild while at 10 days, when renal failure was pronounced, outer cortical afferent arterioles appeared to be moderately constricted. In the 5/6 nephrectomy model of chronic renal failure, the glomeruli were smaller in rats in renal failure than in the controls.

Animals↗

PubMed1986

Quantitative vascular casting of the post-ischemic hydronephrotic kidney.

The renal microvasculature (afferent arteriole) and glomeruli were examined and quantitated by two methods in the post-ischemic hydronephrotic (PIH) kidney. The methods used were: an in vivo examination and controlled perfusion-fixation, quantitative vascular casting examined by scanning electron microscopy. The second method was also applied to the vasculature of the contralateral, functional kidney. The goals of the study were to: validate the quantitative vascular casting method by comparing PIH renal microvascular data from the casting method with in vivo values and determine the extent of microvascular dimensional difference of the PIH kidney from its contralateral functional counterpart. It was determined that the casting values were consistent with the data obtained from the in vivo examination of the afferent arteriole and glomeruli. This finding provides further support for the quantitative renal microvascular casting technique. Using that technique it was determined that the dimensions of the microvasculature and glomeruli of the PIH kidney were severely (and significantly, p less than 0.05) reduced compared to its functional mate. Since these PIH vessels show a significant decrement in size, vascular reactivity and functional data based on the PIH vessels should be looked at cautiously. The vasculature and glomeruli of the PIH kidney might not be totally normal, however structurally, the glomeruli do not appear to be dramatically altered.

Animals↗