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Biomedical subjects

S Black

Publications and source records attributed to S Black.

At least 91 records · Page 5Linked to original sources
PubMed1995

Acute myocardial infarction in Oklahoma: are we different?

Data regarding 787 patients admitted to Saint Francis Hospital in Tulsa, Oklahoma, with acute myocardial infarction (MI) were analyzed to determine circadian variation and to assess demographic and anatomic characteristics. The study population consisted of 634 men (81%) and 153 women (19%). This cohort displayed a circadian rhythm that nearly duplicated a previously published national data base. As was seen nationally, our patients had a peak incidence between 6 AM and noon. Of the total population, 448 patients had acute cardiac catheterization allowing definition of the infarct vessel. The majority of myocardial infarctions were from right coronary artery occlusions. Men were more likely than women to have an anterior MI. Both men and women were more likely to have an inferior MI if they were less than 65 years of age, though this was more pronounced for women. As the population aged, they were more likely to have an anterior myocardial infarction.

Adult↗
PubMed1994

Genetic analyses of yeast protein serine/threonine phosphatases.

Protein phosphorylation is an important regulatory phenomenon in yeasts just as in other eukaryotic cells and controls a wide variety of cellular processes. The importance of protein phosphatases as well as protein kinases as key elements in such control is becoming increasingly clear. Over the past four years since the first yeast protein phosphatase gene was isolated, many more such genes have been described and the number of genes encoding protein phosphatase catalytic subunits in Saccharomyces cerevisiae has comfortably entered double figures. Given the genetic approaches available, yeasts offer powerful systems for addressing the cellular roles of these enzymes. This review summarises the results of genetic studies aimed at determining the functions of protein serine/threonine phosphatases in yeast.

Genes, Fungal↗
PubMed1994

Identifying the mental health needs of children living in families with AIDS or HIV infection.

The present article highlights the mental health needs of children living with loved ones who have AIDS or HIV infection. In addition the article describes an intervention program which is being developed to meet the needs of the children and their families. Children who live in families affected by AIDS and HIV infection, like children who live with other life-threatening illnesses, are vulnerable to psychological distress. They experience numerous separations from parents, changes in the nature and predictability of emotional nurturing, concerns about loss, disruptions in routine and contact with peers, and economic hardship. AIDS and HIV infection present the additional stressors that stem from discrimination, stereotyping, and social ostracism. Finally, many families living with AIDS or HIV infection are disenfranchised, living under the pall of poverty and substance abuse. The intervention program described is being implemented in an urban community mental health clinic to meet the diverse mental health needs of the children living in these families. Preliminary implications of the program are discussed so as to begin a dialogue with other agencies who are challenged to meet the needs of this heterogeneous population.

Acquired Immunodeficiency Syndrome↗
PubMed1994

The effects of loading changes on intraoperative Doppler assessment of mitral regurgitation.

Anesthetic agents may significantly alter the patient's blood pressure, and thus affect the intraoperative assessment of mitral regurgitation. This study examined the impact of an increase in afterload on a variety of parameters thought to reflect the severity of mitral regurgitation, and related them to changes in hemodynamic parameters. Twenty-four patients with mitral regurgitation undergoing cardiac surgery were studied. Following the induction of anesthesia, color-flow mapping of the entire left atrium was performed, and pulmonary vein flow was then measured. Phenylephrine was administered to increase the patients' blood pressures to their preoperative values, and the assessment was repeated. Regurgitant jet area increased 56% (482 +/- 405 v 750 +/- 440 mm2 P < 0.001), and there were significant reductions in systolic pulmonary venous velocity (0.33 +/- 0.17 v 0.18 +/- .31 m/s P < .01) with increases in diastolic flow (0.43 +/- 12 v 0.58 +/- 0.18 m/s P < .001). These changes in pulmonary venous flow were not related to the changes in the driving force across the incompetent mitral valve. Also, an additional six patients developed systolic flow reversal after phenylephrine administration. Intraoperative hemodynamic variations can significantly alter the apparent severity of mitral regurgitation, and this factor must be considered during decision making.

Adult↗
PubMed1994

Cognitive deficits and personality patterns in maternally versus paternally inherited myotonic dystrophy.

Neuropsychological functioning was compared between 7 myotonic dystrophy (MD) patients with maternal inheritance (mMD), 14 MD patients with paternal (pMD) inheritance, and 10 normal controls. Both groups evidenced slowed performance on a measure of information processing speed. However, the pMD group had an otherwise normal neuropsychological profile. In contrast, the mMD group exhibited abnormal scores on measures of intelligence, visual-construction, and some, albeit not all, measures of frontal functioning. No significant differences between the three groups were detected on measures of verbal or visual memory, or on measures of visual-perception. Overall, these findings suggest that inheritance pattern is one important moderating variable in determining the impact of the MD gene on cognitive functioning. Personality assessment revealed a relatively high incidence of dependent tendencies and depressive symptoms, even among pMDs. Given the generally normal cognitive functioning among pMDs, personality/emotional disturbance observed among MD patients may largely reflect their adjustment to having a progressively disabling medical condition, rather than being a direct expression of MD related brain dysfunction.

Adult↗
PubMed1993

A provisional mechanism for regulating the aminoacyl-tRNA synthetases.

A mechanism is outlined for regulating aminoacyl-tRNA synthetases with a nonheme iron-containing protein serving as the key regulator. This mechanism is formulated from experiments with a complex-bound valyl-tRNA synthetase from yeast that is activated by thiols, by tRNA, and by an iron-containing protein preparation with characteristic spectral properties.

Amino Acyl-tRNA Synthetases↗
PubMed1993

Recreational drug use in New Zealand.

A general population sample of 5126 New Zealanders aged 15-45 was surveyed in late 1990 to determine their use of alcohol, tobacco, cannabis, and other illicit drugs. The results show that alcohol and tobacco are the most commonly used drugs. Cannabis had been tried by 43% of the sample, and this level of use appears similar to that in Australia and the United States. Hallucinogens were the next most common illicit drug and had been tried by 8% of the sample. Again the New Zealand rates appear similar to those for the United States or Australia. Much lower levels of use were reported for stimulants, opiates, tranquillizers and solvents than for other illicit drugs. The New Zealand prevalence rates for these substances are lower than those in the United States. The rates for these other classes of drugs are more similar to Australia, but may be slightly lower for stimulants, tranquillizers and solvents.

Journal Article↗
PubMed1993

Measurement of forces applied during the clinical cementation of dental crowns.

Uncertainty exists about the forces applied by dentists during dental crown cementation. A measuring system was developed based around a commercially available miniature (3.8 mm high and 12.7 mm diameter) load cell. The load cell was mounted in a finger stall and the applied force measured. Experimental results suggest that dentists typically apply a force to metal crowns of about 60 N for a few seconds, followed by the application of a steady force of about 20 to 30 N. Lower forces are applied to porcelain crowns.

Crowns↗
PubMed1992

A randomized comparison of transcervical and transabdominal chorionic-villus sampling. The U.S. National Institute of Child Health and Human Development Chorionic-Villus Sampling and Amniocentesis Study Group.

BACKGROUND: Chorionic-villus sampling is done in early pregnancy to obtain fetal cells for the prenatal diagnosis of genetic and chromosomal defects. Transcervical chorionic-villus sampling has been shown to be safe and effective in national trials. Recently, an alternative transabdominal technique has been suggested as potentially easier and safer. METHODS: From April 1987 through September 1989, we prospectively compared transcervical and transabdominal chorionic-villus sampling in 3999 women with singleton pregnancies in whom the risk of a genetically abnormal fetus was increased. Women between 7 and 12 weeks of gestation underwent ultrasonographic evaluation of placental and uterine position. Those with active vaginal infections, active bleeding, or cervical polyps were excluded. If the obstetrician thought either sampling procedure was acceptable, the woman was asked to consent to random assignment to one of the two procedures. Both groups were followed to determine the outcome of pregnancy and the rate of spontaneous fetal loss after chorionic-villus sampling. RESULTS: Among the 3999 women who entered the study, sampling was attempted in 3873 (97 percent), 1944 of whom had been assigned to undergo transcervical sampling and 1929 to undergo transabdominal sampling. Of these 3873 women, sampling was eventually successful in 3863. Sampling was successful after a single insertion of the sampling instrument in 94 percent of the transabdominal procedures and 90 percent of the transcervical procedures. Among the women with cytogenetically normal pregnancies who had sampling because of maternal age, the rate of spontaneous fetal loss through 28 weeks of pregnancy was 2.5 percent in the transcervical-sampling group and 2.3 percent in the transabdominal-sampling group (difference, 0.26 percent; 95 percent confidence interval, -0.5 to 1.0 percent). CONCLUSIONS: Transabdominal and transcervical chorionic-villus sampling appear to be equally safe procedures for first-trimester diagnosis of fetal abnormalities.

Abdomen↗
PubMed1992

Congenital 21-hydroxylase deficiency as a new deletion mutation. Detection in a proband during subsequent prenatal diagnosis by HLA typing and DNA analysis.

A child with 21-OH-def whose 9 weeks' pregnant mother was referred for prenatal diagnosis was found upon very careful histocompatibility testing to lack expression of any of his father's HLA antigens on his peripheral blood lymphocytes. The possibility of alternative paternity was considered to be extremely unlikely after additional genetic marker tests. The conclusion that the affected child's disease resulted from inheritance of a maternal CYP21B (21-OH) deletion and a de novo deletion in the paternal chromosome 6 segment that includes both the CYP21B (21-OH) and HLA genes was confirmed by subsequent DNA analysis using 21-OH, C4, DPB, and PCH6 probes. The presence of a heterozygous RFLP for DPB, the absence of a deletion for either CYP21B (21-OH) or C4 genes, and the presence of a paternal HLA antigen haplotype on the fetal cells additionally indicated that the fetus lacked the same deletion and could be predicted to be completely normal.

Adrenal Hyperplasia, Congenital↗
PubMed1992

Effect of type of anesthesia on blood loss at elective repeat cesarean section.

It has recently been reported that the use of halogenated agents during balanced general anesthesia may result in an increase in blood loss associated with cesarean section. This report has been criticized for failure to control for a variety of other factors that may have contributed to the increased blood loss, particularly the indication for and type of cesarean section. The present study was designed in an attempt to resolve this criticism. Blood loss was evaluated in uncomplicated patients undergoing elective repeat cesarean section under either general anesthesia using a halogenated agent (isoflurane) or regional anesthesia (spinal/epidural). All 117 singleton term, nonlaboring women underwent repeat low transverse cesarean section performed through a midline abdominal incision. Exclusion criteria included maternal medical complications, abnormal placentation, polyhydramnios, presence of uterine leiomyomas, and intraoperative complications. Seventy-five patients (64%) received regional and 42 (36%) received general anesthesia. A greater proportion of women undergoing general anesthesia experienced a postoperative decrease in hematocrit of 5 vol% or more compared with patients receiving regional anesthesia (10 of 42 versus 5 of 75, p = 0.018). Thus, we conclude that women undergoing uncomplicated elective repeat cesarean section under general anesthesia supplemented with a halogenated agent are at risk for increased blood loss compared with those women receiving regional anesthesia. However, the increased blood loss was not clinically significant in this study, since none of the patients required transfusion.

Anesthesia, Conduction↗
PubMed1992

Detection and hemodynamic consequences of venous air embolism. Does nitrous oxide make a difference?

Volume expansion of intravascular air by nitrous oxide (N2O) may improve the sensitivity of monitors used to detect venous air embolism (VAE) and/or exacerbate hemodynamic changes following VAE. The purpose of this study was to determine if the administration of N2O alters the sensitivity (i.e., threshold of detection) of monitors used to detect VAE or the hemodynamic consequences of VAE. Twenty-one dogs were monitored for VAE with precordial Doppler ultrasound, transesophageal echocardiography (TEE), changes in end-tidal carbon dioxide tension (ETCO2), and changes in pulmonary artery pressure (PAP). Venous air was infused at rates between 0.005 and 0.4 ml.kg-1.min-1 during 1 MAC (total anesthetic level) of isoflurane with and without 50% N2O (group 1, n = 7) or isoflurane with and without 75% N2O (group 2, n = 7). The mean quantity of infused air necessary to elicit a positive response in both the presence and absence of N2O was calculated for each monitor. Positive responses were defined as follows: unmistakable audible change in frequency on Doppler ultrasound, visualization of densities consistent with air bubbles in the right cardiac chambers or outflow tract on TEE, a decrease in ETCO2 greater than or equal to 2 mmHg, and an increase in mean PAP greater than or equal to 3 mmHg. In group 3 (n = 7), venous air was infused at rates between 0.1 and 0.8 ml.kg-1.min-1 during 1 MAC (total anesthetic level) of isoflurane with and without 50% N2O. In group 3, N2O administration was discontinued immediately upon Doppler detection of VAE and air infusion continued until mean arterial pressure (MAP) decreased by 10 mmHg.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

User reports of problems associated with alcohol and marijuana.

A general population sample of 5126 New Zealanders aged 15-45 in two regions was surveyed to determine their use of alcohol, tobacco, marijuana, and other illicit drugs. Self-reported problems were recorded on identical scales for alcohol and marijuana in order to make a direct comparison between alcohol and marijuana-related problems. The results suggest that alcohol-related problems were more common than marijuana-related ones in the general population, reflecting the fact that alcohol use was more widespread. Within the 17% of the sample who had used both alcohol and marijuana in the last 12 months more problems were reported from alcohol, once again reflecting differences in amounts consumed. Among heavier users of marijuana both alcohol and marijuana-related problems were more commonly reported than in the general sample. Problems were reported at similar levels for both drugs and the pattern of problems is somewhat similar.

Adolescent↗
PubMed1992

HIV risks among minority drug users in a small city.

In 1989, African-American and Mexican-American drug users (n = 220) in a small southern city were interviewed, in street settings, about their HIV behavioral risks and their readiness to reduce risks. Both ethnic groups contained large numbers of cocaine and heroin users. Mexican Americans were more likely to use heroin, prefer injection, and share needles with other drug users than were African Americans. Sexual risk-taking in both groups was high, with very low levels of condom use, high levels of exchanging sex for drugs and money, and high levels of having multiple sexual partners. Mexican Americans were more likely than African Americans to have regular partners who used drugs. Intravenous drug users in both ethnic groups were at high risk for HIV infection, reporting high levels of multiple drug use, daily drug use, needle sharing, never cleaning needles, and exchanging sex for drugs or money. Readiness to reduce HIV risks was also high in both groups, as evidenced by the response to questions about the use of free preventive services, HIV testing, and concern about AIDS. Implications for research and preventive programs among minority drug users in small cities are discussed.

Adult↗
PubMed1991

The effects of global normothermic hypoperfusion on the processed electroencephalogram in patients.

This study examined the effects of global normothermic hypoperfusion on the compressed spectral array (CSA) processed electroencephalogram (EEG) during high-dose narcotic anesthesia. Fifteen patients undergoing cardiac electrophysiologic surgery were studied. The patients were anesthetized with a standard high-dose narcotic technique and then connected to a Nicolet Pathfinder I CSA EEG analysis system using seven subdermal electrodes in a modified International 10-20 configuration. There were 167 intervals of profound hypotension ranging from 8 to 96 seconds. During these periods the cerebral perfusion pressure was almost zero. Despite 38 intervals up to 32 seconds long, 6 of the 15 patients had no EEG changes. Overall, there were 36 (21.6%) ischemic EEG recordings. None of the patients developed neurological complications. The incidence of EEG changes was much lower than expected from other studies. Either the processed EEG was inherently insensitive, the high-dose narcotic masked the processed EEG effects of hypoperfusion, or the narcotic provided a previously unknown protective effect.

Anesthesia, General↗
PubMed1991

Intraoperative detection of patent foramen ovale by transesophageal echocardiography.

This study reports the intraoperative use of contrast and Doppler echocardiography techniques to diagnose patent foramen ovale (PFO). Fifty patients without known atrial septal defects undergoing elective cardiovascular surgery were studied. A 5-MHz esophageal echocardiographic probe was used to image the fossa ovalis (FO) and 10 ml agitated saline was injected into the right atrium during apnea. Echocardiographic contrast was then injected during end-inspiration at 20-cmH2O airway pressure. When opacification of the right atrium was complete, the airway pressure was released. During these maneuvers, color and pulsed-wave Doppler interrogation of the atrial septum were also performed. Right-to-left passage of saline contrast across the interatrial septum was seen in 11 of 50 patients (22%). Doppler echocardiography demonstrated a PFO in 2 patients without contrast evidence of shunting. Thus, the combination of contrast and Doppler echocardiography identified a 26% (13 of 50) prevalence of PFO, approximating the previously reported autopsy rate of 25%. These contrast and Doppler techniques may be useful in detecting patients at risk for paradoxical emboli and in identifying candidates for closure of the PFO.

Adult↗
PubMed1991

The single-stranded-DNA-binding protein encoded by the Escherichia coli F factor can complement a deletion of the chromosomal ssb gene.

Genes encoding single-stranded-DNA-binding proteins (SSBs) are carried by a variety of large self-transmissible plasmids, and it previously has been shown that these plasmid-borne genes can complement conditional lethal alleles of the ssb gene on the Escherichia coli chromosome for cellular viability. We have tested one of the plasmid-borne ssb genes, the ssf gene from the E. coli F factor, for its ability to complement total deletion of the chromosomal ssb gene for viability. We have found that ssf can complement the ssb deletion, but only when it is present on a high-copy-number plasmid. Cells that are totally dependent on the F-factor-encoded SSB for viability manifest growth properties indicative of problems in DNA replication.

Amino Acid Sequence↗