Biomedical subjects

M Nowak

Publications and source records attributed to M Nowak.

At least 73 records · Page 4Linked to original sources

PubMed1999

Back problems. Radiology and scintigraphy.

Radiology and, more recently, scintigraphy are important ancillary diagnostic aids in the diagnosis of a horse with suspected back pain. Although the image quality is restricted by the size of the patient, radiographs have been used for several decades. With the introduction of modern fast-screen film systems, the quality of the images has greatly improved. These imaging techniques allow assessment of the anatomy and physiology of structures in the spine that are difficult or impossible to palpate. This article reviews the techniques and limitations of imaging the equine back, in addition to correlation imaging results and clinical findings.

Animals↗

PubMed1999

Command-related distribution of regional cerebral blood flow during attempted handgrip.

To localize a central nervous feed-forward mechanism involved in cardiovascular regulation during exercise, brain activation patterns were measured in eight subjects by employing positron emission tomography and oxygen-15-labeled water. Scans were performed at rest and during rhythmic handgrip before and after axillary blockade with bupivacaine. After the blockade, handgrip strength was reduced to 25% (range 0-50%) of control values, whereas handgrip-induced heart rate and blood pressure increases were unaffected (13 +/- 3 beats/min and 12 +/- 5 mmHg, respectively; means +/- SE). Before regional anesthesia, handgrip caused increased activation in the contralateral sensory motor area, the supplementary motor area, and the ipsilateral cerebellum. We found no evidence for changes in the activation pattern due to an interaction between handgrip and regional anesthesia. This was true for both the blocked and unblocked arm. It remains unclear whether the activated areas are responsible for the increase in cardiovascular variables, but neural feedback from the contracting muscles was not necessary for the activation in the mentioned areas during rhythmic handgrip.

Adult↗

PubMed1999

Effects of neurotensin and bombesin on the secretory and proliferative activity of regenerating rat adrenal cortex.

Neurotensin (NT) and bombesin (BM)-like peptides are known to be involved in the regulation of the rat hypothalamo-pituitary-adrenal axis. By using selective NT- and BM-receptor antagonists (NT-A and BM-A, respectively) we investigated whether endogenous NT and BM-like peptides play a role in the control of rat adrenal secretion and growth during enucleation-induced regeneration. At day 5 of regeneration, NT-A did not affect the plasma concentrations of aldosteronc (PAC) and corticosterone (PBC), but at day 8, it raised both PAC and PBC over the respective baseline value; the simultaneous administration of NT abolished this effect of NT-A. BM-A did not alter PAC and PBC at day 5 of regeneration, while at day 8 it enhanced PBC, an effect reversed by BM. NT-A did not alter mitotic index, and BM-A lowered it at both day 5 and day 8 of regeneration, an effect suppressed by the simultaneous administration of BM. Collectively, these findings allow us to draw the following conclusions: 1) endogenous NT and BM-like peptides influence adrenocortical regeneration in rats; 2) NT exerts a tonic inhibitory action on both aldosterone and corticosterone secretion, without affecting cell-proliferation rate; and 3) BM-like peptides exert a tonic suppressive effect on corticosterone production, coupled with a clear-cut stimulating effect on cell proliferation.

Adrenal Cortex↗

PubMed1999

Cholecystokinin, acting through the A receptor subtype, stimulates the proliferative activity of adrenocortical cells and thymocytes in the rat.

Cholecystokinin (CCK) is a multifunctional regulatory peptide, which acts through two main subtypes of receptors, named CCK-A and CCK-B. Evidence indicates that CCK modulates cell proliferation in various tissues in a paracrine manner, and proofs are available of the presence of CCK in both adrenal glands and thymus. Hence, we have investigated the possible mitogenic action of this peptide on these two tissues, by evaluating the /1000 of metaphase-arrested cells after vincristin injection (mitotic index). The systemic administration of CCK (three subcutaneous injections of 20 nmol/kg, 28, 16 and 4 h before the sacrifice) increased the mitotic index in both the outer adrenal and thymus cortexes of immature (20-day-old) rats and the enucleated adrenal gland of adult (2-month-old) animals at day 5 and 8 of regeneration. The simultaneous administration of equimolar doses of a selective CCK-A receptor antagonist blocked the effect of CCK, while a CCK-B antagonist was ineffective. These findings indicate that CCK exerts a marked CCK-A-mediated proliferogenic effect on both adrenal cortex and thymus in the rat, the physiological relevance of which, however, remains to be demonstrated. In fact, the administration of the CCK-A antagonist alone was ineffective, thereby casting doubts on the role played by endogenous CCK in the maintenance and stimulation of adrenal and thymus growth.

Adrenal Cortex↗

PubMed1999

[The evaluation of blood flow in uterine arteries in girls with polycystic ovary syndrome by transvaginal color Doppler ultrasonography].

OBJECTIVE: The aim of this study was to evaluate of blood flow in uterine arteries in girls with PCOS and to determine whether uterine blood flow variations are associated with endocrine findings typical of PCOS. METHODS: Seventy two girls with clinical, endocrinologic and ultrasonographic features of PCOS (mean age 18.8 +/- 1.3 years) were examined. The control subject consisted of twenty girls with regular, ovulation cycles. None of these girls had received hormonal treatment for at least 6 months before the study. Pelvic ultrasound examination was made in each patient with Acuson 128 XP/10 with the 4/5/7 MHz transvaginal transducer. Examination was performed in early follicular phase. Blood flow was made in each patient in the ascending branches of uterine arteries. Index values pulsatility index (PI) and resistance index (RI) were used for the purpose of better comparison of the data. Associations between values of PI and RI and hormones (testosterone, luteinizing hormone) were examined. RESULTS: No significant differences between PI and RI of the left and right uterine artery was observed. PI in PCOS girls was mean 3.19 +/- 0.52 ranged from 2.1 to 4.3, in control girls PI was mean 2.33 +/- 0.36 ranged from 1.6 to 3.1. The PI was positively correlated (r = 0.435, p < 0.01) with testosterone and PI was positively correlated (r = 0.450, p < 0.001) with LH. The RI in PCOS patients was mean 0.87 +/- 0.04 ranged from 0.74 to 0.93, in control girls 0.72-0.87, mean 0.80 +/- 0.04. The RI was positively correlated (r = 0.466, p < 0.001) with testosterone and RI was positively correlated (r = 0.492, p < 0.001) with LH. CONCLUSIONS: The elevated uterine artery resistance was observed in girls with PCOS.

Arteries↗

PubMed1999

A 15O-H2O PET study of meditation and the resting state of normal consciousness.

The aim of the present study was to examine whether the neural structures subserving meditation can be reproducibly measured, and, if so, whether they are different from those supporting the resting state of normal consciousness. Cerebral blood flow distribution was investigated with the 15O-H20 PET technique in nine young adults, who were highly experienced yoga teachers, during the relaxation meditation (Yoga Nidra), and during the resting state of normal consciousness. In addition, global CBF was measured in two of the subjects. Spectral EEG analysis was performed throughout the investigations. In meditation, differential activity was seen, with the noticeable exception of V1, in the posterior sensory and associative cortices known to participate in imagery tasks. In the resting state of normal consciousness (compared with meditation as a baseline), differential activity was found in dorso-lateral and orbital frontal cortex, anterior cingulate gyri, left temporal gyri, left inferior parietal lobule, striatal and thalamic regions, pons and cerebellar vermis and hemispheres, structures thought to support an executive attentional network. The mean global flow remained unchanged for both subjects throughout the investigation (39+/-5 and 38+/-4 ml/100 g/min, uncorrected for partial volume effects). It is concluded that the (H2)15O PET method may measure CBF distribution in the meditative state as well as during the resting state of normal consciousness, and that characteristic patterns of neural activity support each state. These findings enhance our understanding of the neural basis of different aspects of consciousness.

Adult↗

PubMed1998

The application of microspheres from the copolymers of lactide and epsilon-caprolactone to the controlled release of steroids.

The microspheres made of the copolymers of lactide and epsilon-caprolactone were used for the controlled release of progesterone and beta-estradiol. The copolymers contained 83-94% of l or d,l-lactide. The influence of the microstructure of lactidyl blocks in the copolymer chains on the drug release rate was studied. More uniform release rate was observed in the case of the copolymer derived from d,l-lactide as composed to l-lactide. For the copolymer containing 83-94% of d,l-lactide units the progesterone and beta-estradiol release rate in vitro was found to be practically constant within over 40 days. The in vivo studies performed on rats revealed that the period of constant release rate of beta-estradiol can be prolonged to about 70 days. The microspheres made of the applied poly-(d,l-lactide-co-epsilon-caprolactone) are the convenient system for long time release of steroids.

Animals↗

PubMed1998

Muscle metabolism from near infrared spectroscopy during rhythmic handgrip in humans.

The rate of metabolism in forearm flexor muscles (MO2) was derived from near-infrared spectroscopy (NIRS-O2) during ischaemia at rest rhythmic handgrip at 15% and 30% of maximal voluntary contraction (MVC), post-exercise muscle ischaemia (PEMI), and recovery in seven subjects. The MO2 was compared with forearm oxygen uptake (VO2) [flow x (oxygen saturation in arnterial blood-oxygen saturation in venous blood, SaO2 - SvO2)], and with the 31P-magnetic resonance spectroscopy-determined ratio of inorganic phosphate to phosphocreatine (P(I):PCr). During ischaemia at rest, the fall in NIRS-O2 was more pronounced [76 (SEM 3) to 3 (SEM 1)%] than in SvO2 [71 (SEM 3) to 59 (SEM 2)%]. During the handgrip, NIRS-O2 was lower at 30% compared to 15% MVC [58 (SEM 3) v.s. 67 (SEM 3)%] while the SvO2 was similar [29 (SEM 3) v.s. 31 (SEM 4)%]. Accordingly, MO2 as well as P(I):PCr increased twofold, while VO2 increased only 30%. During PEMI after 15% and 30% MVC, NIRS-O2 fell to 9 (SEM 1)% and "0", but the use of oxygen by forearm muscles was not reflected in SvO2. During reperfusion after PEMI, the peak NIRS-O2 was lowest after intense exercise, while for SvO2 the reverse was seen. The discrepancies between NIRS-O2 and SvO2, and therefore between the estimates of the metabolic rate, would suggest significant limitations in sampling venous blood which is representative of the flexor muscle capillaries. In support of this contention, SvO2 and venous pH decreased during the first seconds of reperfusion after PEMI. To conclude, NIRS-O2 of forearm flexor muscles closely reflected the exercise intensity and the metabolic rate determined by magnetic resonance spectroscopy but not that rate derived from flow and the arterio-venous oxygen difference.

Adult↗

PubMed1998

The effects of bone plug length and screw diameter on the holding strength of bone-tendon-bone grafts.

The effect of bone plug length and Kurosaka screw (DePuy, Warsaw, IN) diameter on graft holding strength of the bone-tendon-bone construct was determined. Random length porcine bone plugs were assigned to fixation with 7 or 9 mm Kurosaka screws. Peak load to failure was determined. There was a significant decrease in peak load to failure of the 5-mm long bone plugs compared with longer bone plugs. No difference was found between longer lengths of bone plug in either the 7- or 9-mm screw diameter groups. The 9-mm diameter screws significantly increased peak load to failure for both 1- and 2-cm bone plug lengths.

Animals↗

PubMed1998

Arginine-vasopressin and corticotropin-releasing hormone are sequentially involved in the endothelin-1-induced acute stimulation of rat pituitary-adrenocortical axis.

The acute effect of endothelin-1 (ET-1) on the hypothalamo-pituitary-adrenal (HPA) axis has been investigated in the rat. The plasma concentrations of arginine-vasopressin (AVP), ACTH, aldosterone and corticosterone have been measured by RIA 30 and 60 min after ET-1 administration. ET-1 (2.0 nmol kg(-1) raised AVP plasma concentration at both 30 and 60 min. ET-1 did not alter the ACTH plasma level at 30 min, but markedly increased it at 60 min. ACTH response was unaffected by the simultaneous administration of AVP-receptor antagonists (AVP-As) Des-Gly-[Phaa1,D-Tyr(Et)2,Lys6,Arg8]-vasopressin or [Deamino-Pen1,Tyr(Me)2,Arg8]-vasopressin (20 nmol kg(-1), but abolished by the corticotropin-releasing hormone (CRH)-receptor antagonist alpha-helical-CRH(9-41) (alpha-CRH, 10 nmol kg(-1). ET-1 evoked significant rises in the blood levels of aldosterone and corticosterone at both 30 and 60 min. AVP-As abrogated the response at 30 min, while alpha-CRH was ineffective. Both AVP-As and alpha-CRH partially reversed adrenocortical secretory response at 60 min. Collectively, these findings confirm that systemically administered ET-1 stimulates rat HPA axis, and provide evidence that the mechanism underlying this effect may involve the sequential activation of AVP and CRH release.

Adrenocorticotropic Hormone↗

PubMed1998

The weight-conscious adolescent: body image, food intake, and weight-related behavior.

PURPOSE: To explore how adolescents who try to lose weight differ from those who do not in relation to body image, food intake, knowledge about food, and sources of information about food, nutrition, and weight loss. METHODS: Data were collected from 12-15-year-old school students in North Queensland, Australia by questionnaire. RESULTS: Boys who attempted weight loss reduced sweet foods and snacks, while concurrently increasing healthy foods such as fruit, yogurt, and low-fat milk. Girls who attempted weight loss ate breakfast, lunch, snacks, milk, bread, meat, and many sweet and fatty foods less often than other girls. Some reduction in meals, snacks, core foods, and sweet fatty foods, but not savory fatty foods, remained after the weight loss attempt. Boys attempting weight loss had better knowledge about high-fat and high-sugar foods than other boys, but there was no difference for girls. Girls attempting weight loss were more likely than other girls to think that core foods such as bread, potatoes, and dairy products should be reduced, whereas boys were more likely to think that sweet foods should be reduced. The majority of students who had attempted weight loss during the previous year considered themselves overweight, while few weight-conscious students were satisfied with their bodies. CONCLUSIONS: The weight-conscious adolescents in this study, especially the girls, exhibited restrictive eating practices and a preoccupation with a slim image. Adolescents need a food culture based on foods to eat rather than foods to avoid, and an understanding of suitable weight-control measures.

Adolescent↗

PubMed1998

Syringocystadenoma papilliferum of the male breast.

A 39-year-old man presented with a 2-cm, mildly tender mass in the right breast of many years' duration. Microscopic examination showed a syringocystadenoma papilliferum. Because of its location in the breast, we studied the lesion for immunohistochemical markers for apocrine differentiation. Gross cystic disease fluid protein-15 (GCDFP-15) staining yielded negative results in the cystic luminal epithelial cells, whereas GCDFP-15 and lysozyme staining yielded strongly positive results in the epithelial cells of adjacent tubular apocrine glands. Focal strong lysozyme positivity was seen in the cystic luminal epithelial cells. These findings do not support apocrine differentiation in this case, despite its location in the breast, an organ rich in specialized apocrine (lactiferous) glands. To our knowledge, this represents the first reported case of syringocystadenoma papilliferum of the male breast. We present the clinical and pathologic features of this unusual case and a review of the literature.

Adenoma, Sweat Gland↗

PubMed1998

Resistance to antimicrobial chemotherapy: a prescription for research and action.

The growing problem of resistance to antimicrobial chemotherapy was discussed by participants at the February 1995 workshop at Emory University on population biology, evolution, and control of infectious diseases. They discussed the nature and source of this problem and identified areas of research in which information is lacking for the development of programs to control of the emergence and spread of resistant bacteria. Particular attention was given to theoretical (mathematical modeling) and empirical studies of the within and between-host population biology (epidemiology) and the evolution of microbial resistance to chemotherapeutic agents. Suggestions were made about the kinds of models and data needed, and the procedures that could be employed to stem the ascent and dissemination of resistant bacteria. This article summarizes the observations and recommendations made at the 1995 meeting and in the correspondence between participants that followed. It concludes with an update on the theoretical and empirical research on the between- and within-host population biology and evolution of resistance to antimicrobial chemotherapy most of which has been done since that meeting.

Bacteria↗

PubMed1998

Transfection of the type II TGF-beta receptor into colon cancer cells increases receptor expression, inhibits cell growth, and reduces the malignant phenotype.

OBJECTIVE: To determine if transfection of SW48 colon cancer cells with the type II transforming growth factor-beta (TGF-beta) receptor restores growth inhibition and reverses the in vitro and in vivo malignant phenotype. SUMMARY BACKGROUND DATA: The authors have previously shown that SW48 colon cancer cells that are replication error positive in both alleles lack functional cell surface TGF-beta type I (RI) and type II (RII) receptors and are insensitive to TGF-beta1-induced growth inhibition. METHODS: SW48 cells were stably transfected with the cDNA for the normal type II TGF-beta receptor (RII). Once transfected, the cells were evaluated for in vitro phenotypic changes and in vivo changes in tumor growth. RESULTS: Denaturing sequencing gel electrophoresis of the reverse transcriptase-polymerase chain reaction product from SW48 cells revealed that the RII coding sequence contained a single base deletion mutation. When these cells were transfected with normal RII cDNA, Northern and Western blot analyses revealed increased levels of RII mRNA and protein. Affinity labeling techniques revealed that RII-transfected SW48 cells produced functional RI and RII protein. Transfection of SW48 cells also led to changes in cell phenotype, as shown by inhibition of both in vitro growth rate and incorporation of [3H]-thymidine. SW48 cells expressing normal RII also exhibited reduced cloning efficiency in semisolid medium and reduced growth as a xenograft in NOD/LtSz-scid/J mice. CONCLUSIONS: The results confirm that RII is a tumor-suppressor protein that is required for TGF-beta-induced growth inhibition in SW48 colon cancer cells.

Animals↗

PubMed1998

Effect of immune activation on the dynamics of human immunodeficiency virus replication and on the distribution of viral quasispecies.

Virus replication in a human immunodeficiency virus (HIV)-infected individual, as determined by the steady-state level of plasma viremia, reflects a complex balance of viral and host factors. We have previously demonstrated that immunization of HIV-infected individuals with the common recall antigen, tetanus toxoid, disrupts this steady state, resulting in transient bursts of plasma viremia after immunization. The present study defines the viral genetic basis for the transient bursts in viremia after immune activation. Tetanus immunization was associated with dramatic and generally reversible shifts in the composition of plasma viral quasispecies. The viral bursts in most cases reflected a nonspecific increase in viral replication secondary to an expanded pool of susceptible CD4(+) T cells. An exception to this was in a patient who harbored viruses of differing tropisms (syncytium inducing and non-syncytium inducing [NSI]). In this situation, immunization appeared to select for the replication of NSI viruses. In one of three patients, the data suggested that immune activation resulted in the appearance in plasma of virus induced from latently infected cells. These findings illustrate certain mechanisms whereby antigenic stimulation may influence the dynamics of HIV replication, including the relative expression of different viral variants.

Amino Acid Sequence↗

PubMed1998

[The use of maternal serum cytokines in the predicting of the efficacy of tocolytic therapy in case of the threat of preterm labor].

OBJECTIVES: The purpose of our study was to evaluate the use of maternal serum IL-8, IL-6, IFN-gamma levels in the predicting of the efficacy of tocolytic therapy in preterm labor. MATERIALS AND METHODS: We investigated prospectively the group of 47 women in singleton pregnancies with threatened preterm labor in less than 36 weeks gestation and administered tocolytic therapy. RESULTS: In 19 of them tocolysis failed (group II and they delivered premature newborns (the group I--successful tocolysis consisted of remaining 28 women). The incidence of clinical chorioamnionitis, histologic chorioamnionitis and inherited infection of newborns was significantly higher among women refractory to tocolytic therapy (10.2%, 36.8%, 26.3% versus 0%, 3.6%, 0%, respectively, p < 0.05). Maternal serum IL-8, IL-6, IFN-gamma (by means of ELISA technique) and CRP, WBC, ESR levels were measured at the admission to the study. The mean WBC, ESR and the median (range) IFN-gamma (0 (0-7.1) and 0.9 (0-10.4) pg/ml, respectively) didn't differ in both groups. The concentrations of serum IL-8, IL-6, CRP were significantly higher in the group of failed tocolysis (median (range): IL-8: 22.7 (6.3-83.2) vs 3.0 (0-26.0) pg/ml; IL-6: 7.4 (0-21.0) vs 0 (0-11.3) pg/ml; CRP: 1.8 (0.6-7.0) vs 0.6 (0.6-3.9) mg/dl; p < 0.05). Serum IL-8 determinations (definition of abnormal test: > 8 pg/ml) were found the most reliable in the prediction of tocolysis failure with a sensitivity 87.5%, specificity 81.8%, positive predictive value 77.8%, negative predictive value 90% and accuracy 84.2%. Also reliable were IL-6 determinations (IL-6 > 6 pg/ml had a sensitivity 75%, specificity 90.9%, positive predictive value 85.7%, negative predictive value 83.3% and accuracy 84.2%) and CRP determinations (CRP > 1.2 mg/dl had a sensitivity 75%, specificity 81.8%, positive predictive value 75%, negative predictive value 81.8% and accuracy 78.9%). The efficacy of IFN-gamma, WBC and ESR was significantly lower. CONCLUSIONS: Our data revealed that the maternal serum IL-8, IL-6 and CRP determinations are very useful in the predicting of the efficacy of tocolytic therapy in women with threatened preterm labor. The use of IFN-gamma, WBC, ESR was significantly lower.

Cytokines↗

PubMed1998

[The cost of laparoscopy in the diagnosis of female infertility].

DESIGN: The aim of the study was to estimate the usefulness of laparoscopy in diagnostics of women's infertility. MATERIALS AND METHODS: This study is a retrospective review of the notes of 133 infertile women who had undergone laparoscopic procedures--in 88 (66.2%) patients the reason of their infertility was unknown (study group I) and in 45 (33.8%) pelvic pathology (PCO syndrome-37 cases, endometriosis-6 cases and tubal inpatency-2 cases) was supposed (study group II). RESULTS: In 96 (72.2%) patients (in 51 from group I and in 45 from group II) pelvic pathology was estimated (p < 0.0001 in comparison with diagnostic estimation before laparoscopy). Most frequent pathology in women with unexplained infertility was seen: endometriosis, adhesions and tubal inpatency. During laparoscopy procedure we changed totally preoperative diagnosis in 43.6% patients (58 cases--51 from group I and 7 from group II) and in 9.8% women additional pelvic abnormalities were detected. CONCLUSION: In authors opinion the laparoscopic procedure is very helpful in infertile women and ought to be included in diagnostic standard in cases of unexplained infertility.

Adult↗

PubMed1998

[Maternal serum cytokines concentrations during normal pregnancy and labor].

OBJECTIVES: The purpose of our study was to determine maternal serum concentrations of IL-8, IL-6, IFN-gamma during normal pregnancy and labor. MATERIALS AND METHODS: Maternal serum IL-8, IL-6 and IFN-gamma levels were measured by means of ELISA technique in 41 healthy pregnant women in 22-42 week gestation and 15 healthy women in labor at term. All newborns and afterbirths had no signs of infection. RESULTS: IL-8 values for pregnant women ranged from 1.98 to 35.2 pg/ml with the median value 10.24 pg/ml, and the 95th percentile 24.5 pg/ml. IL-8 values for women in labor at term ranged from 3.96 to 54.8 pg/ml with the median 10.4 pg/ml. No statistically significant changes in serum IL-8 concentration were observed during pregnancy or in labor. Serum IL-6 concentrations in pregnant women ranged from 0 to 21.7 pg/ml with the median value 0 pg/ml, and the 95th percentile 15.5 pg/ml. Serum IL-6 concentrations in women in labor at term were significantly higher (p < 0.05): ranged from 0 to 39.2 pg/ml with the median 10.1 pg/ml and 95-th percentile 33.5 pg/ml. Maternal serum IFN-gamma concentrations in pregnant women ranged from 0 to 9.8 pg/ml with the median value 3.9 pg/ml, the 95th percentile 9.2 pg/ml and didn't differ during labor at term: range from 0 to 14.5 pg/ml, median 1.9 pg/ml. CONCLUSIONS: Our data revealed that maternal serum IL-8 concentrations didn't changed during the course of pregnancy and in labor. Women in labor had significantly elevated serum IL-6 concentrations compared to those in pregnancy. We didn't observed such changes in serum IFN-gamma levels.

Adult↗