Biomedical subjects

P Alm

Publications and source records attributed to P Alm.

At least 37 records · Page 2Linked to original sources

PubMed2000

Identification and distribution of nitric oxide synthase in the brain of adult zebrafish.

Nitric oxide (NO) is proposed to be involved in developmental and plastic processes. We investigated the presence and distribution of nitric oxide synthase (NOS) in the zebrafish (Danio rerio) using molecular and histochemical techniques. A partial gene sequence corresponding to the neuronal NOS isoform (nNOS) was identified, and in situ hybridization revealed cellular nNOS mRNA expression throughout the brain of adult zebrafish, distributed in distinct central nuclei and in proliferation zones. NOS immunoreactivity and nicotinamide adenine dinucleotide phosphate diaphorase activity partly coincided with the nNOS mRNA expression, however was present also in additional neuronal and non-neuronal cell types. The results indicate the occurrence of different NOS isoforms in the adult brain, of which nNOS may participate in neurotransmission, and in mechanisms related to the continuous growth and neuronal plasticity of the teleost brain.

Age Factors↗

PubMed2000

Calcitonin and calcitonin gene-related peptide in the human prostate gland.

BACKGROUND: Calcitonin-related peptides have been found in the human prostate, and calcitonin (CT) and calcitonin gene-related peptide (CGRP) have been demonstrated in subpopulations of neuroendocrine (NE) cells. The purpose of this study was to determine the concentrations of CT and CGRP as well as the densities of NE cells in normal prostates, benign prostatic hyperplasia (BPH), and carcinoma of the prostate (CAP). METHODS: In 42 specimens of radical prostatectomy, the number of CT- and CGRP-immunoreactive NE cells in areas of normal and BPH tissue was determined, and compared with CAP tissue using immunocytochemistry. In addition, by radioimmunoassay (RIA), tissue levels of CT and CGRP were analyzed in extracts from areas of normal, BPH, and CAP tissue, as verified by adjacent histologic sections. RESULTS: A significant decrease in CT-immunoreactive NE cells was observed in hyperplastic nodules of BPH in comparison to normal tissue. These findings were in parallel with a significant reduction in tissue CT level in BPH compared to normal tissue. There was also a marked, but statistically nonsignificant, reduction in CT levels in CAP tissue. In contrast, levels of CGRP in BPH and CAP tissue did not show any significant differences compared to normal tissue. CONCLUSIONS: CT and CGRP are present in NE cells of the human prostate. Calcitonin levels are significantly reduced in BPH, in parallel with a decreased number of CT-immunoreactive NE cells, whereas no significant changes in tissue levels of CGRP were observed. The functional significance of these findings is discussed.

Aged↗

PubMed2000

Erectile dysfunction in cyclic GMP-dependent kinase I-deficient mice.

The generation of nitric oxide (NO) in penile erectile tissue and the subsequent elevation of cyclic GMP (cGMP) levels are important for normal penile erection. Current treatments of erectile dysfunction elevate either cGMP levels by blocking cGMP degrading phosphodiesterase 5 or cyclic AMP (cAMP) levels by intrapenile injection of prostaglandin E1. The molecular target or targets of cGMP in erectile tissue and the role of cAMP for normal penile erection are not known. Herein, we report that mice lacking cGMP-dependent kinase I (cGKI) have a very low ability to reproduce and that their corpora cavernosa fail to relax on activation of the NO/cGMP signaling cascade. Elevation of cAMP by forskolin, however, induces similar relaxation in normal and cGKI-null corpus cavernosum. In addition, sperm derived from cGKI-null mice is normal, can undergo acrosomal reactions, and can efficiently fertilize eggs. Altogether, these data identify cGKI as the downstream target of cGMP in erectile tissue and provide evidence that cAMP signaling cannot compensate for the absence of the cGMP/cGKI signaling cascade in vivo.

Animals↗

PubMed2000

Role of nitric oxide in blood-brain barrier permeability, brain edema and cell damage following hyperthermic brain injury. An experimental study using EGB-761 and Gingkolide B pretreatment in the rat.

The role of oxidative stress in hyperthermia induced upregulation of constitutive and inducible isoforms of nitric oxide synthase (NOS) in the central nervous system (CNS) was investigated using immunohistochemistry in a rat model. Exposure of rats to heat stress at 38 degrees C for 4 h resulted in marked upregulation of constitutive NOS (cNOS) and a mild but significant expression of inducible NOS (iNOS) in several brain regions exhibiting leakage of the blood-brain barrier (BBB), brain edema formation and cell injury. Pretreatment with the potent antioxidative compound EGB-761 or its constituent, Ginkgolide B significantly attenuated upregulation of cNOS and iNOS in the brain and also reduced the BBB permeability disturbances, brain edema and cell injury. These neuroprotective effects were most marked in the EGB-761 pretreated rats. Our observations strongly suggest that (i) EGB-761 and Ginkgolide B pretreatment offer significant neuroprotection in hyperthermic brain injury, (ii) upregulation of cNOS and iNOS are injurious to the cell and, (iii) oxidative stress plays an important role in NOS expression and cell injury.

Animals↗

PubMed2000

A new antioxidant compound H-290/51 attenuates upregulation of constitutive isoform of heme oxygenase (HO-2) following trauma to the rat spinal cord.

Influence of a new antioxidant compound H-290/51 on carbon monoxide (CO) production following spinal cord injury was examined using immunohistochemistry of the constitutive isoform of heme oxygenase-2 (HO-2) in a rat model. Subjection of rats to 5 h spinal cord injury by making an incision into the right dorsal horn of the T10-11 segments resulted in upregulation of HO-2 in the injured and adjacent T9 and T12 segments. At this time, disruption of the blood-spinal cord barrier (BSCB) permeability, edema formation and cell injury were more pronounced. Pretreatment with H-290/51 (50 mg/kg, p.o., 30 min before trauma) significantly attenuated the HO-2 immunoreactivity along with breakdown of the BSCB permeability, edema and cell injury. These results for the first time demonstrate that the antioxidant compound H-290/51 is capable of attenuating HO-2 expression and thereby influencing CO production. Furthermore, our observations indicate that oxidative stress is involved in CO production, as reflected by HO-2 expression, which is injurious to the cord and H-290/51 exerts powerful neuroprotective effects in spinal cord injury.

Animals↗

PubMed2000

Topical application of brain derived neurotrophic factor influences upregulation of constitutive isoform of heme oxygenase in the spinal cord following trauma an experimental study using immunohistochemistry in the rat.

Influence of brain derived neurotrophic factor (BDNF) on carbon monoxide (CO) production following spinal cord injury was examined using expression of the constitutive isoform of the enzyme hemeoxygenase-2 (HO-2) in a rat model. A longitudinal incision of the right dorsal horn on the T10-11 segment markedly increased the HO-2 immunostaining in the cord at 5 h. At this time period, breakdown of the blood-spinal cord barrier (BSCB) and edema formation were quite prominent. Repeated topical application of BDNF (20 microliters of a 1 microgram/ml solution) over the exposed surface of the cord significantly attenuated the edematous expansion of the cord and the disturbances in the BSCB permeability. In BDNF-treated rats, expression of HO-2 immunoreactivity was considerably reduced. These results strongly suggest that BDNF is neuroprotective in spinal trauma and this growth factor has the capacity to attenuate CO production by downregulating HO-2 expression.

Animals↗

PubMed2000

Spinal nerve lesion induces upregulation of constitutive isoform of heme oxygenase in the spinal cord. An immunohistochemical investigation in the rat.

The influence of carbon monoxide (CO) on chronic spinal nerve lesion induced spinal cord neurodegeneration was examined using immunohistochemical expression of the constitutive isoform of its synthesising enzyme, hemeoxygenase-2 (HO-2) in a rat model. Spinal nerve lesion at L-5 and L-6 level was produced according to the Chung model of neuropathic pain and rats were allowed to survive for 8 weeks. Sham operated rats, in which the spinal nerves were exposed but not ligated, served as controls. Ligation of spinal nerves in rats resulted in an upregulation of HO-2 expression which was most pronounced in the ipsilateral gray matter of the spinal cord compared to the contralateral side. In these rats, morphological investigations showed distorted neurons, membrane disruption, synaptic damage and myelin vesiculation. Sham operated rats did not show an upregulation of HO-2 expression and the structural changes in the spinal cord were absent. These observations strongly suggest that spinal nerve lesion is associated with an increased production of CO which is somehow contributing to the neurodegenerative changes in the spinal cord, not reported earlier.

Animals↗

PubMed2000

A new antioxidant compound H-290/51 attenuates nitric oxide synthase and heme oxygenase expression following hyperthermic brain injury. An experimental study using immunohistochemistry in the rat.

Influence of a new anti-oxidant compound H-290/51 on expression of nitric oxide synthase (NOS) and heme oxygenase (HO) enzymes responsible for nitric oxide (NO) and carbon monoxide (CO) production, respectively was examined in the CNS following heat stress in relation to cell injury. Exposure of rats to 4h heat stress at 38 degrees C in a biological oxygen demand (BOD) incubator (relative humidity 50-55%, wind velocity 20-25cm/sec) resulted in profound edema and cell injury in many parts of the cerebral cortex, hippocampus, cerebellum, thalamus, hypothalamus and brain stem. Immunostaining of constitutive isoforms of neuronal NOS (nNOS) and HO-2 revealed marked upregulation in damaged and distorted neurons located within the edematous brain regions. Pretreatment with H-290/51 (50 mg/kg, p.o., 30 min before heat stress) significantly reduced the edematous swelling and cell injury and resulted in a marked attenuation of nNOS and HO-2 expression. These observations suggest that upregulation of NOS and HO is associated with cell injury, and the antioxidant compound H-290/51 is neuroprotective in heat stress.

Animals↗

PubMed2000

Heme oxygenase-1, heme oxygenase-2 and biliverdin reductase in peripheral ganglia from rat, expression and plasticity.

The expression of inducible and constitutive heme oxygenase and biliverdin reductase was studied in normal and cultured peripheral ganglia from adult rats, using immunocytochemistry and in situ hybridization. Dramatic changes were induced by one to two days' culturing of dorsal root ganglia, nodose ganglia, otic ganglia, sphenopalatine ganglia and superior cervical ganglia. An up-regulation of inducible heme oxygenase was found in satellite cells of the cultured nodose ganglia, dorsal root ganglia, sphenopalatine ganglia and otic ganglia, whereas only a few satellite cells in the superior cervical ganglia responded with an increase in inducible heme oxygenase immunoreactivity. In the superior cervical ganglia inducible heme oxygenase also appeared in a subpopulation of macrophages. During culturing, expression of inducible heme oxygenase immunoreactivity also increased in axons and in nerve cell bodies. In situ hybridization corroborated the immunocytochemical findings, revealing a strong up-regulation of inducible heme oxygenase messenger RNA in satellite cells, and less pronounced up-regulation in nerve cell bodies. Constitutive heme oxygenase immunoreactivity was found in most neurons in all of the ganglia studied. No significant changes in constitutive heme oxygenase immunoreactivity could be observed in cultured ganglia. Biliverdin reductase immunoreactivity was barely detectable in any of the normal ganglia; however, after culturing it appeared in axons, single nerve cell bodies and nerve cell nuclei. The results show that inducible heme oxygenase is up-regulated in peripheral ganglia after axonal injury, and suggest a role for carbon monoxide in cellular signaling and a requirement for the antioxidant (bilirubin) during the regeneration process.

Animals↗

PubMed2000

Impaired relaxation of stomach smooth muscle in mice lacking cyclic GMP-dependent protein kinase I.

1. Guanosine 3', 5'-cyclic monophosphate (cyclic GMP)-dependent kinase I (cGKI) is a major receptor for cyclic GMP in a variety of cells. Mice lacking cGKI exhibit multiple phenotypes, including severe defects in smooth muscle function. We have investigated the NO/cGMP- and vasoactive intestinal polypeptide (VIP)/adenosine 3', 5'-cyclic monophosphate (cyclic AMP)-signalling pathways in the gastric fundus of wild type and cGKI-deficient mice. 2. Using immunohistochemistry, similar staining patterns for NO-synthase, cyclic GMP- and VIP-immunoreactivities were found in wild type and cGKI-deficient mice. 3. In isolated, endothelin-1 (3 nM - 3 microM)-contracted, muscle strips from wild type mice, electrical field stimulation (1 - 16 Hz) caused a biphasic relaxation, one initial rapid, followed by a more slowly developing phase. In preparations from cGKI-deficient mice only the slowly developing relaxation was observed. 4. The responses to the NO donor, SIN-1 (10 nM - 100 microM), and to 8-Br-cyclic GMP (10 nM - 100 microM) were markedly impaired in strips from cGKI-deficient mice, whereas the responses to VIP (0.1 nM - 1 microM) and forskolin (0.1 nM - 1 microM) were similar to those in wild type mice. 5. These results suggest that cGKI plays a central role in the NO/cGMP signalling cascade producing relaxation of mouse gastric fundus smooth muscle. Relaxant agents acting via the cyclic AMP-pathway can exert their effects independently of cGKI.

Animals↗

PubMed2000

Expression of DNA topoisomerases in chronic proliferative kidney disease.

BACKGROUND: Circulating autoantibodies to human topoisomerases have been reported in glomerular kidney disease associated with scleroderma and systemic lupus erythematosus. However, limited information is available about the expression of topoisomerases in the kidney under normal and pathological conditions. METHODS: The expression of DNA topoisomerases I and IIalpha was studied by immunohistochemistry on archival biopsies from 70 patients with chronic renal diseases. Normal kidney tissue was examined for comparison. Topoisomerase I was detected by means of monoclonal antibody (mAb) C21, and topoisomerase IIalpha was detected by means of mAb Ki-S4. In addition, mAb Ki-M1p was used to assess the density of monocytic infiltrates. All parameters were assessed in a semiquantitative manner. RESULTS: Glomerular topoisomerase IIalpha levels were increased in mesangial proliferative glomerulonephritis (MPGN), rapidly progressive glomerulonephritis (RPGN), and lupus nephritis (LN) and were reduced in membranous glomerulonephritis (MGN), chronic transplant nephropathy (CTN), and tubulointerstitial nephritis (TIN). Tubular epithelia displayed high topoisomerase IIalpha levels in mesangiocapillary glomerulonephritis (MCGN), RPGN, TIN, miscellaneous entities (MISC) and LN, and displayed low levels in MPGN and CTN. Topoisomerase I expression was high in the glomeruli of focal segmental glomerulosclerosis (FSGS), MCGN, and RPGN and was extreme in LN, whereas it was strikingly diminished in the glomeruli of MGN, CTN, and TIN. Almost all conditions displayed lower tubular topoisomerase I levels than normal kidney, except for LN, in which the enzyme content was markedly increased. Increased glomerular monocytic infiltrates were found in FSGS, MCGN, RPGN, TIN, and LN, and tubulointerstitial Ki-M1p+ cells were seen at high numbers in MCGN, RPGN, TIN, MISC, and LN. The expression of the topoisomerases I and IIalpha was significantly correlated; also, topoisomerases showed a positive association with the density of monocytic infiltrates. The parameter profiles exhibited significant differences between distinct types of chronic renal disease. CONCLUSION: Topoisomerase IIalpha expression is tightly linked to cell cycling, and topoisomerase I is likely a reflection of gene transcription. Rapidly progressing glomerular disease therefore appears to be accompanied by active mesangial cell proliferation and increased metabolic activity in glomerular cells. The correlation with inflammatory infiltrates is likely to reflect a positive feedback mechanism involving cytokines, growth factors, and adhesion molecules. Assessment of topoisomerases may therefore be of diagnostic help and might allow prognostic predictions. Provided that our observations are supported by clinicopathological follow-up studies, one might envisage the use of topoisomerase inhibitors in the therapy of chronic proliferative renal disease refractory to current treatment protocols.

Antibodies, Monoclonal↗

PubMed2000

Cholinergic nerves in human corpus cavernosum and spongiosum contain nitric oxide synthase and heme oxygenase.

PURPOSE: To characterize the distribution of cholinergic nerves in the human corpus cavernosum (CC) and spongiosum (CS) using antibodies to the vesicular acetylcholine transporter (VAChT), and to compare this distribution to those of other transmitters/mediators or transmitter/mediator generating enzymes (heme oxygenases: HO-1 and HO-2; neuronal and endothelial NO synthases: nNOS and eNOS; vasoactive intestinal polypeptide: VIP; and tyrosine hydroxylase: TH), and to investigate NO- and carbon monoxide (CO)-mediated effects. MATERIALS AND METHODS: Immunocytochemistry, confocal laser scanning microscopy, radioimmunoassay, and functional in vitro studies. RESULTS: Along strands of smooth muscle in the CC and CS, rich numbers of VAChT-, nNOS-, VIP-, TH-, and very few HO-1-immunoreactive (-IR) nerve fibers were observed. Immunoreactivities for VAChT and nNOS, VAChT and VIP, and nNOS and VIP, were generally found in the same varicose nerve terminals. TH-IR nerve fibers or terminals did not contain immunoreactivities for VAChT, NOS or VIP. In the endothelium lining penile arteries, immunoreactivities for eNOS, HO-1, and HO-2 were detected. Single endothelial cells, lining the sinusoidal walls of the CC and CS, were found also to contain eNOS and HO-immunoreactivities. Noradrenaline (NA)-contracted preparations of CC and CS were relaxed by NO, CO, carbachol and by electrical stimulation of nerves. Inhibition of NO synthesis abolished electrically- and carbachol-induced relaxation. In NA-activated strips, relaxation induced by exogenously applied NO, but not those by CO, were accompanied by increases in intracellular levels of cyclic GMP. CONCLUSIONS: VAChT, NOS and VIP are found in the same nerve terminals within the human CC and CS, suggesting that these terminals comprise a distinct population of parasympathetic, cholinergic nerves. Endothelially derived NO and the HO/CO system may have a complementary role in penile erection.

Acetylcholine↗

PubMed2000

Chronic blockade of NO synthase paradoxically increases islet NO production and modulates islet hormone release.

Islet production of nitric oxide (NO) and CO in relation to islet hormone secretion was investigated in mice given the NO synthase (NOS) inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME) in their drinking water. In these mice, the total islet NO production was paradoxically increased, reflecting induction of inducible NOS (iNOS) in background of reduced activity and immunoreactivity of constitutive NOS (cNOS). Unexpectedly, normal mice fasted for 24 h also displayed iNOS activity, which was further increased in L-NAME-drinking mice. Glucose-stimulated insulin secretion in vitro and in vivo was increased in fasted but unaffected in fed mice after L-NAME drinking. Glucagon secretion was increased in vitro. Control islets incubated with different NOS inhibitors at 20 mM glucose displayed increased insulin release and decreased cNOS activity. These NOS inhibitors potentiated glucose-stimulated insulin release also from islets of L-NAME-drinking mice. In contrast, glucagon release was suppressed. In islets from L-NAME-drinking mice, cyclic nucleotides were upregulated, and forskolin-stimulated hormone release, CO production, and heme oxygenase (HO)-2 expression increased. In conclusion, chronic NOS blockade evoked iNOS-derived NO production in pancreatic islets and elicited compensatory mechanisms against the inhibitory action of NO on glucose-stimulated insulin release by inducing upregulation of the islet cAMP and HO-CO systems.

Animals↗

PubMed2000

Sympathetic pathways and adrenergic innervation of the penis.

The sympathetic nervous system is important for penile function: it mediates detumescence and may contribute to the maintenance of the penis in a non-erect state. The sympathetic preganglionic neurons are found in the intermediolateral gray matter of the spinal cord. Postganglionic neurons are located to the sympathetic chain ganglia, the inferior mesenteric, hypogastric and pelvic ganglia, and possibly to ganglia near the target organ. Sympathetic fibres can be found in the pelvic, cavernous, and pudendal nerves. Stimulation of the sympathetic pathways to the penis may, however, also produce erection. It has been suggested that the suprasacral vasodilator pathway is a sympathetic cholinergic pathway, operating through cholinergic neurons in the pelvic plexus. In the penis, there is a rich sympathetic, adrenergic innervation of the corpus cavernosum (CC) and the vasculature, and in particular of the helicine arteries. Sympathetic, adrenergic nerves also contain neuropeptide Y. Parasympathetic cholinergic nerves, which mediate CC relaxation and erection, contain not only acetylcholine, but also vasoactive intestinal polypeptide, nitric oxide synthase, and probably other mediators and/or mediator-synthesizing enzymes. Activation of sympathetic adrenergic nerves causes release of noradrenaline, acting on alpha-adrenoceptors in the trabecular smooth muscle of the CC and in penile vessels. The role of interactions between different transmitters and mediators, released from nerves or generated locally, in the regulation of contraction and relaxation of CC and penile vessels, needs further study.

Animals↗

PubMed2000

Sympathetic pathways and adrenergic innervation of the penis.

Journal Article↗

PubMed2000

Cystometric evaluation of bladder function in non-anesthetized mice with and without bladder outlet obstruction.

PURPOSE: To develop a model for cystometric study of bladder function in the awake mouse, and to characterize urodynamically and immunohistochemically the non-obstructed and infravesically obstructed mouse bladder. MATERIALS AND METHODS: Non-obstructed Balb/CJ mice, and mice with bladder outlet obstruction after surgical, partial ligation of the urethra underwent continuous cystometry as previously described for rats. Bladders were also investigated by immunohistochemistry. RESULTS: During the period of cystometry, reproducible micturition patterns were obtained. Marked differences in the urodynamic parameters between non-obstructed and obstructed mice were revealed. In mice subjected to urethral obstruction, micturition pressure (p <0.05), threshold pressure (p <0.05), bladder capacity (p <0.001), micturition volume (p <0.001), and residual volume (p <0.05) increased significantly. There was no difference in basal pressure or compliance between non-obstructed and obstructed mice. Non-voiding bladder activity was consistently recorded in obstructed mice; both frequency and amplitude increased significantly (p <0.01). Compared with non-obstructed bladders, obstructed bladders showed hypertrophy of the bladder wall and various degrees of "patchy denervation" of the detrusor. When tested in non-obstructed mice capsaicin, prostaglandin E2 (intravesical administration) and apomorphine (subcutaneous administration) induced bladder overactivity. CONCLUSIONS: Continuous cystometry can be reproducibly performed in awake, freely moving non-obstructed mice and mice with bladder outflow obstruction. The changes induced by infravesical obstruction in mice were similar to those previously found in rats. This model may be useful for investigations of genetically modified mice.

Animals↗

PubMed2000

Neurotrophic factors influence upregulation of constitutive isoform of heme oxygenase and cellular stress response in the spinal cord following trauma. An experimental study using immunohistochemistry in the rat.

The influence of brain derived neurotrophic factor (BDNF) or insulin like growth factor-1 (IGF-1) on spinal cord trauma induced carbon monoxide (CO) production and cellular stress response was examined using immunostaining of the constitutive isoform of the hemeoxygenase (HO-2) enzyme and the heat shock protein (HSP 72kD) expression in a rat model. Subjection of rats to a 5 h spinal trauma inflicted by an incision into the right dorsal horn at T10-11 segment markedly upregulated the HO-2 and HSP expression in the adjacent spinal cord segments (T9 and T12). Pretreatment with BDNF or IGF-1 significantly attenuated the trauma induced HSP expression. The upregulation of HO-2 was also considerably reduced. These results show that BDNF and IGF-1 attenuate cellular stress response and production of CO following spinal cord injury which seems to be the key factors in neurotrophins induced neuroprotection.

Animals↗

PubMed1999

Immunologic proliferation marker Ki-S2 as prognostic indicator for lymph node-negative breast cancer.

BACKGROUND: Proper treatment of lymph node-negative breast cancer depends on an accurate prognosis. To improve prognostic models for this disease, we evaluated whether an immunohistochemical marker for proliferating cells, Ki-S2 (a monoclonal antibody that binds to a 100-kd nuclear protein expressed in S, G2, and M phases of the cell cycle), is an accurate indicator of prognosis. METHODS: We studied 371 Swedish women with lymph node-negative breast cancer; the median follow-up time was 95 months. The fraction of tumor cells in S phase was assessed by flow cytometry, and tumor cell proliferation was measured immunohistochemically with the monoclonal antibodies Ki-S2 and Ki-S5 (directed against the nuclear antigen Ki-67). A combined prognostic index was calculated on the basis of the S-phase fraction, progesterone receptor content, and tumor size. RESULTS: In multivariate analyses that did or did not (263 and 332 observations, respectively) include the S-phase fraction and the combined prognostic index, the Ki-S2 labeling index (percentage of antibody-stained tumor cell nuclei) emerged as the most statistically significant predictor of overall survival, disease-specific survival, and disease-free survival (all two-sided P<.0001). In the risk group defined by a Ki-S2 labeling index of 10% or less, life expectancy was not statistically significantly different from that of age-matched women without breast cancer, whereas the group with a high Ki-S2 labeling index had an increased risk of mortality of up to 20-fold. CONCLUSIONS: Cellular proliferation is a major determinant of the biologic behavior of breast cancer. Prognosis is apparently best indicated by the percentage of cells in S through M phases of the cell cycle. Measurement of the Ki-S2 labeling index of a tumor sample may improve a clinician's ability to make an accurate prognosis and to identify patients with a low risk of recurrence who may not need adjuvant therapy.

Adult↗