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Biomedical subjects

M Katz

Publications and source records attributed to M Katz.

At least 127 records · Page 7Linked to original sources
PubMed1997

[Comparison of stress echocardiography and radionuclide ventriculography in the diagnosis of cardiomyopathy in patients receiving chemotherapy for malignant diseases].

BACKGROUND AND OBJECTIVE: Early evidence of drug-induced cardiomyopathy (CMP) is of great importance in haematological treatment, especially with anthracyclines. Stress echocardiography (SEC) has proved of value in determining left ventricular function at rest and under stress in patients with heart disease. The study was undertaken to assess the value of SEC in comparison with radionuclide ventriculography (RNV). PATIENTS AND METHODS: 63 unselected patients with malignant tumour (20 women, 43 men; mean age 49 +/- 15 years) underwent SEC and RNV. No chemotherapy had yet been started in 17 of them, 43 had received anthracyclines as main component of the chemotherapy (mean anthracycline dose 339 +/- 251 mg/m2). Left ventricular ejection fraction (LVEF) was measured by both SEC and RNV at rest and during standardized stress (recumbent ergometry). Both methods were applied and results measured independently by two examiners. RESULTS: The time interval between the two tests averaged 1 = 2 days. EC could be performed at rest in 62 of 63 and under stress in 59 of 63 patients (RNV: 63 of 63 and 54 of 63, respectively). Resting LVEF was 61 +/- 8% by SEC and 64 +/- 9% by RNV (P < 0.05). LVEF during stress, measured by SEC, was 71 +/- 11% and 73 +/- 10% by RNV (not significant). Mean LVEF increase between rest and stress was 9 +/- 10% by SEC and 9 +/- 8% by RNV (not significant). CONCLUSION: SEC is a satisfactory alternative to RNV in the assessment of ventricular function in patients receiving chemotherapy. It is less involved and more cost-effective than RNV, avoids radiation exposure and provides additional information on heart size and segmental contraction abnormalities.

Acute Disease↗
PubMed1997

MODED: microcephaly-oculo-digito-esophageal-duodenal syndrome.

We report on 4 families with microcephaly, type A brachydactyly, variable learning disabilities, short stature, duodenal atresia, patent ductus arteriosus (PDA), hallux valgus, restricted elbow and finger movements, and amesophalangy and syndactyly of toes. Three previous families manifested all signs of the syndrome, and in another four reports the phenotype was incomplete. These cases are reviewed. Penetrance of digital and toe anomalies is almost complete and microcephaly is present in 78% of known cases. Short stature was present in 70% of our cases, but this is probably an overestimation. Esophageal and duodenal atresias were present in 25% of known cases. Correction for ascertainment bias gave a lower estimate of 16.6%. Learning disabilities were present in 31% of all patients. Longitudinal follow-up suggested that hypoplasia or absence of the diaphyseal ossification centers is the primary cause of the phalangeal changes. Observations in a 9-year-old girl, followed since age 3.3, suggest that the eventual absence of the middle phalanges of the toes may be caused by fusion.

Abnormalities, Multiple↗
PubMed1997

[Effect of the Yom Kippur fast on parturition].

Food-withdrawal has been proposed as a possible mechanism for initiating the onset of labor in animals and humans. The hypothesis was based upon the reported increase in deliveries of infants during the Yom Kippur fast. We studied the effect of the fast on full term deliveries of Jewish women, with non-fasting Bedouin women as controls (1988-1995, 1,313 Jewish and 1,091 Bedouin deliveries). To determine the effect of Yom Kippur itself, delivery rates on Sukkot and Yom Kippur were compared in both groups. The mean delivery rate in the Jewish population was significantly higher during Yom Kippur and the day after, than during the 7 days before Yom Kippur (15.1 +/- 5.1 and 14.6 +/- 4.7 vs 10.7 +/- 3.5, p < 0.04 and p < 0.01, respectively). There was an increase in delivery rate during the 6 hours before the end of the fast. In the Bedouin women there were no changes in delivery rate during any of these periods. There were no significant differences in the rates of deliveries during the Sukkot festival between Jewish and Bedouin women. We conclude that fasting is associated with a significant increase in the rate of deliveries at term.

Arabs↗
PubMed1997

Accommodation without feedback suggests directional signals specify ocular focus.

Accommodation was monitored continuously under open-loop conditions while subjects viewed a sinusoidally oscillating sine-wave grating (0.2 Hz; +/- 1 D; 2.7 c/d; 0.56 contrast) in a Badal optometer. The target was illuminated by monochromatic light (590 nm) or white light (3000 K) with longitudinal chromatic aberration (LCA) normal, doubled, neutralized and reversed. Subjects (12) accommodated well in white light with LCA normal and doubled (mean gains = 0.85 and 0.94), gain was reduced in the neutralized condition (0.54), in monochromatic light (0.43), and especially when LCA was reversed (0.30). The results suggest that accommodation responds to changes in the relative contrast of spectral components of the retinal image and perhaps to the vergence of light.

Accommodation, Ocular↗
PubMed1997

Elevated serum ferritin level in acute myocardial infarction.

Serum ferritin level was determined in 20 patients with acute myocardial infarction (AMI) during the first 10 days post infarction. Starting on the second day, a gradual increase in serum ferritin level was detected, reaching a maximum of four times the initial level on the sixth day after the infarction. In addition, a significant increase in ferritin content was found in the peripheral blood monocytes on the fifth day after the event. The control group comprised six patients suffering from chest pains not due to AMI. In all of them the serum ferritin level was found to be within normal limits. Peripheral blood monocytes derived from healthy individuals incubated with hydrocortisone, showed a significant enhancement of their ferritin content, a finding suggesting that these cells activated by steroids during stress could be a source of the increased serum ferritin level following AMI. It is concluded that measurement of serum ferritin may be used as a complementary tool for confirming the diagnosis of AMI.

Aged↗
PubMed1997

A risk profile of street youth in northern California: implications for gender-specific human immunodeficiency virus prevention.

PURPOSE: To assess human immunodeficiency virus (HIV) risk behaviors of street youth and to determine whether risk behaviors differ by gender or housing status. METHODS: Using systematic street-based sampling in four Northern California cities, we recruited 429 street youth (mean age = 19.2 years). Participants completed a structured interview which was used to assess sexual and drug HIV risk behaviors. RESULTS: The majority of youth were heterosexual (85%), white (77%), male (68%), and currently without any type of stable housing (75%). Although 60% of the sample had had vaginal sex in the past 30 days, only 44% used a condom the last time they had sex. About one-third (32%) of the sample reported ever injecting drugs, and almost all reported lifetime use of multiple drugs including D-lysergic acid diethylamide (96%), marijuana (90%), alcohol (81%), cocaine (70%), and speed (70%). Compared to males, females were equally likely to use injection and noninjection drugs, but were more likely to be sexually active (P < .001), were more likely to have been diagnosed with a sexually transmitted disease (P = .005), and were less likely to report consistent condom use (P = .003) or intent to use condoms consistently in the future (P = .005). Compared with those with stable housing, youth who were currently without such housing reported higher rates of injection, and other drug use; females without stable housing were less likely to have used condoms the last time they had vaginal intercourse. CONCLUSION: The high level of HIV risk behavior in this street-based sample of youth, particularly females and youth without stable housing, suggests an urgent need for gender-specific prevention efforts and an increased range of housing options.

Adolescent↗
PubMed1997

Terms of mutualism.

Explore the source record for details and available documents.

Disease Transmission, Infectious↗
PubMed1997

Bilateral femoral stress fractures in a child due to in-line (roller) skating.

We report a child who presented with a limp following 6 weeks of strenuous roller skating. Directed X-rays on admission were normal but a 99mTc-methylene diphosphanate bone scan demonstrated increased uptake in the mid-thirds of the femurs compatible with grade IV stress fracture. Immediate abstention from roller skating for 5 weeks resulted in a complete cure. The "new" side effect of this increasingly popular sport is discussed with regard to paediatric stress fractures and to other roller skating-associated injuries.

Child, Preschool↗
PubMed1996

The effect of simian immunodeficiency virus infection in vitro and in vivo on the cytokine production of isolated microglia and peripheral macrophages from rhesus monkey.

Microglia are the major target for human immunodeficiency virus (HIV) infection within the central nervous system. Because only a few cells are productively infected, it has been suggested that an aberrant cytokine production by this cell population may be an indirect mechanism leading to the development of neurological disorders in HIV-infected patients. Therefore we decided to study the secretion pattern of several interleukins (IL) by microglial cells and peripheral blood macrophages isolated from uninfected and simian immunodeficiency virus (SIV)-infected Rhesus monkeys. We found that uninfected, unstimulated primate microglia produce more IL-6 and less TNF alpha than peripheral blood macrophages, but generate comparable levels of IL-1 beta and IL-8. After infection with SIV in vitro, synthesis of all cytokines tested is increased compared to uninfected cultures and to peripheral blood macrophages. Microglia isolated from infected animals produce more IL-8 and TNF alpha than the uninfected cultures and display a strongly increased capacity to secrete TNF alpha upon stimulation with lipopolysaccharide. In addition, production of IL-6 by in vivo-infected microglia increases with time in culture to very high levels despite the fact that only a few cells contained replicating virus. These findings clearly show that the cytokine production of microglia is impaired after SIV infection both in vitro and in vivo and that a low level of viral replication is sufficient for these alterations to occur. In conclusion, the results of this study further support a possible role of cytokines in the pathogenesis of neuro-AIDS.

Animals↗
PubMed1996

Prediction of spontaneous preterm birth by fetal fibronectin and uterine activity.

OBJECTIVE: To evaluate the usefulness of fetal fibronectin and home uterine contraction assessment in predicting preterm birth (before 34 weeks) in at-risk asymptomatic women. METHODS: One hundred fifty women were enrolled prospectively; five were lost to follow-up, leaving 145 women available for analysis. Because patients with preterm labor before 34 weeks' gestation most commonly develop this problem after 28 weeks, the period of 26-28 weeks' gestation was selected prospectively as the first window for prediction and study analysis. Eighty-five of 145 asymptomatic women at high risk for preterm birth had both home uterine contraction assessment of 2 hours per day and one or more cervical sampling(s) for fetal fibronectin measurement at 26-28 weeks. A positive home uterine contraction assessment was defined as contractions exceeding two per hour averaged over the 2-week study interval. Positive fetal fibronectin was defined as greater than 50 ng/mL. RESULTS: Fourteen of the 85 women (16.5%) delivered before 34 weeks. Home uterine contraction assessment alone had a sensitivity, specificity, positive predictive value, and negative predictive value for preterm birth of 64, 85, 45, and 92%, respectively; fetal fibronectin alone was associated with values of 43, 89, 43, and 89%, respectively. A positive home uterine contraction assessment was associated with a relative risk (RR) for preterm birth of 5.9% (95% confidence interval [CI] 2.4-14.2), whereas a positive fetal fibronectin demonstrated an RR of 3.8 (95% CI 1.5-9.4). When both assessments were positive, all patients delivered before 34 weeks and there was an RR of 27.0 (95% CI 8.7-84.1) compared with those with both tests being negative. Only two patients with both tests negative delivered before 34 weeks (negative predictive value 96%). CONCLUSION: Both the home uterine contraction assessment and fetal fibronectin accurately predicted preterm birth before 34 weeks. When both tests were combined, the predictive ability improved substantially.

Adult↗
PubMed1996

Nitric oxide synthase inhibitor NG-monomethyl-L-arginine preserves sperm motility after swim-up.

OBJECTIVE: To evaluate the effect of NG-monomethyl-L-arginine (L-NMMA) on sperm motility. DESIGN: Controlled study using motile sperm suspensions obtained by the swim-up technique. SETTING: Endocrine Laboratory, Department of Obstetrics and Gynaecology, University College London Medical School. PATIENTS: Men attending the Reproductive Medicine Unit at University College London Hospitals, Obstetric Hospital, for routine fertility investigations. INTERVENTIONS: Motile sperm suspensions were incubated with either culture medium (control) or L-NMMA (test) for 24 hours at 37 degrees C. MAIN OUTCOME MEASURE: Motion characteristics were assessed manually and by computer-assisted sperm motility analyzer. RESULTS: In all 23 preparations either equivalent or significantly higher percentage total motility and percentage rapidly motile sperm were observed in the test compared with the control samples at 24 hours. There were no significant differences in motion characteristics between test and control specimens at 6 hours. CONCLUSIONS: NG-monomethyl-L-arginine inhibits the formation of nitric oxide; its ability to prevent sperm motility decline indicates that the arginine-nitric oxide pathway may play a role in modulating sperm motility and motility survival.

Enzyme Inhibitors↗