The transfer of zidovudine (AZT) across human placenta was studied using an in vitro perfusion system with independent maternal and fetal circulations. AZT is transferred toward the fetus more rapidly than L-glucose (transfer index 1.5), a water-soluble molecule smaller than AZT (267 vs. 180 Da) that passively diffuses across the placenta. The transfer rate is proportional to the concentration in the maternal perfusate over a range of 0.03-300 microM. Transfer rate in the reverse direction, toward the maternal perfusate, also exceeds that of L-glucose and fails to show saturability. These observations are consistent with simple diffusion. The partition of AZT and glucose between perfusion buffer and octanol is 1.04 and 0.013, respectively, indicating that AZT is more lipophilic and providing a reasonable explanation for the more rapid transfer. AZT is extensively metabolized by the placenta to more polar and as yet unidentified metabolites that are not released into the perfusate. The possibility that the placental accumulation of such metabolite(s) may exert an antiviral action and may also affect placental function must be considered.

Chromatography, High Pressure Liquid↗

PubMed1990

The effect of Orem's self-care model on nursing care in a nursing home setting.

The need of the functionally disabled for nursing care is a primary rationale for institutionalization in long-term care settings. However, maintenance of the self-care abilities that nursing home residents retain is an important component of their quality of life. Nurses are in an important position to encourage and sustain residents' abilities to participate in their care. Nevertheless, without specifying the role of the resident in care, nursing interventions may inadvertently reinforce dependency and apathy at the expense of autonomy, control and well-being. Data from nursing home care records and interviews suggest that nursing staff using Orem's Self-Care Deficit Nursing Theory differ in their nursing assessments and goals of care from staff on a control unit. Further study is recommended of the influence of the model on staff perspectives of care and on interventions which support nursing home residents' self-care ability and well-being.

Aged↗

PubMed1990

Quantitative morphometric analysis of brain growth using magnetic resonance imaging.

Using a simple image analysis system, we have established normative data obtained from magnetic resonance imaging (MRI) scans for the relative size and growth of the major structural domains of the brain. Midsagittal scans of the head were analyzed in 95 subjects aged 0 to 20 years. Only scans with no demonstrable structural abnormalities of the brain were utilized. Age-related changes in the relative growth of specific structures were calculated by dividing patients into 5-year age increments. No age-related changes were found in the size of the posterior fossa, supratentorial intracranial space, or cisterna magna relative to the total intracranial vault space. A significant (P less than .01) increase in the size of the corpus callosum relative to that of the supratentorial structures and relative to the total intracranial vault space was noted to occur between the 6- to 10-year-old and 11- to 15-year-old age groups. This may reflect an increase in myelination of the corpus callosum that occurs during this period. A small reduction in the ratio of the posterior fossa to the supratentorial space was found between the 0- to 5-year-old and the 6- to 10-year-old age groups, but the biological significance of this difference is uncertain. It appears from these data that quantitative analysis of MRI scans can be used to draw objective conclusions about the relative sizes and growth of the major brain structures. The development of normative data for these structures and the simplicity of the methodology should have many clinical applications in the assessment of aberrant brain development.

Adolescent↗

PubMed1990

Neuroimaging findings in Alexander's disease.

We present the findings from magnetic resonance imaging, computed tomographic scan, and single photon emission computed tomography of the brain in a 2-year-old girl with Alexander's disease. Computed tomographic scans showed prominent low-density white matter throughout the cerebral hemispheres. Magnetic resonance imaging showed increased T2 signal from the cerebral white matter but not the cerebellum or brain stem. Single photon emission computed tomography revealed diminished cerebral metabolism, particularly in the frontal regions, as compared with the cerebellum.

Astrocytes↗

PubMed1990

Motor unit potential analysis in carnitine palmitoyl transferase deficiency.

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Adolescent↗

PubMed1990

An introduction to using children's drawings as an assessment tool.

This article is intended to familiarize the ambulatory care provider with possible uses of children's drawings as assessment tools. Drawings can be a useful adjunct in detecting perceptual-motor difficulties and developmental delay, and can provide clues to self-image and family dynamics. Piaget's theory of cognitive development provides a framework to evaluate the child's intellectual development as reflected in drawings. The developmental scales of Koppitz are presented as a practical screening tool. The Koppitz scales include both developmental norms and items that might indicate emotional problems. Observing the child's drawing of the family provides clues to family dynamics. Becoming highly skilled in the evaluation of children's drawings requires a familiarity with neurophysiology, education, psychology, and psychoanalytic and developmental theory, along with intuition and practice. This article presents an introduction to evaluating children's drawings.

Ambulatory Care↗

PubMed1990

Outpatient and abbreviated hospitalization for vitreoretinal surgery.

We retrospectively reviewed 255 consecutive scleral buckling and vitrectomy operations dividing the patients into two groups. One group was managed traditionally with general anesthesia and postoperative hospitalization. The second group was managed with local anesthesia and with no hospitalization or abbreviated hospitalization whenever possible. There was no difference in the technical or functional success rates achieved in the two groups. We conclude that vitreoretinal surgery may be performed safely and effectively on an outpatient basis in selected cases.

Adolescent↗

PubMed1989

Effects of cannabis smoked together with a substance sold as Mandrax.

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Benzodiazepines↗

PubMed1989

Characteristics of tripeptide transport in human jejunal brush-border membrane vesicles.

These studies are aimed at characterizing the transport of the tripeptide, glycylglycyl-L-proline (GlyGlyPro) across human jejunal brush-border membrane vesicles. GlyGlyPro (0.65 mM) was hydrolyzed by brush-border membrane vesicles with the extent of hydrolysis per mg protein being 23% at 0.5 min, 57% at 1 min and complete hydrolysis at 60 min. Treatment of the membrane vesicles with gel-complexed papain (to remove membrane peptidases) resulted in minimal hydrolysis of GlyGlyPro up to 10 min of incubation. Measurement of GlyGlyPro influx with papain-treated vesicles in the presence of increasing medium osmolarity showed that uptake occurred into an osmotically reactive intravesicular space. Transport of GlyGlyPro with normal and papain-treated membrane vesicles was similar in the presence of an inward Na+ or K+ gradient. No overshoot phenomenon was observed in the presence of an inward proton gradient (extravesicular pH 5.5; intravesicular pH 7.5). An interior negative membrane potential induced by a K+ diffusion potential in the presence of valinomycin stimulated the uptake of the peptide. The effect of increasing concentrations on initial rates of GlyGlyPro uptake revealed the presence of a saturable component as well as a diffusional component. Preloading the membrane vesicles with 20 mM glycylsarcosylsarcosine stimulated uptake by 4-fold. Uptake of GlyGlyPro was inhibited greater than 50% by dipeptides and tripeptides and less than 15% by free amino acids. These results indicate that GlyGlyPro uptake in jejunal brush-border membrane vesicles is not energized by a Na+ or proton gradient and that transport occurs by carrier-mediated and diffusional processes.

Amino Acid Sequence↗

PubMed1989

Intravenous gamma-globulin, antiphospholipid antibodies, and pregnancy.

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Abortion, Habitual↗

PubMed1989

Knowledge about AIDS and self-reported behaviour among Zimbabwean secondary school pupils.

Knowledge about AIDS and self-reported sexual behaviour was studied among 1532 (893 male, 633 female) Zimbabwean secondary school pupils drawn from 12 schools. Most subjects knew that AIDS is fatal and incurable. However, over 40% of subjects believed that most people with AIDS in Africa are homosexual. Over 40% of respondents did not know that many HIV seropositive individuals look healthy. Nearly 40% of participants believed that HIV can be contracted from toilet seats and 54% of subjects believed that mosquitos can transmit HIV. Pupils from homes in urban areas were better informed about AIDS than were those from homes in rural areas. Forty-six percent of males and nearly 3% of females were reportedly sexually experienced. It is suggested that female under-reporting of sexual activity occurred. Nearly 16% of males reported coital experience with a prostitute. The implications of these findings for future AIDS awareness campaigns in Zimbabwe are considered.

Acquired Immunodeficiency Syndrome↗

PubMed1989

A comparison of two pulmonary artery mixed venous oxygen saturation catheters during the changing conditions of cardiac surgery.

Continuous mixed venous oxygen saturation (SvO2), using modified pulmonary artery (PA) catheters, can assist in the management of cardiac surgery patients. Two FDA-approved catheters are available for SvO2 monitoring. One system uses two wavelengths of light and the other is a three-wavelength system. The present study was designed to determine the accuracy of the two catheters during cardiac surgery. Sixty-five consecutive patients were assigned to one of the two catheter groups. Data were collected pre- and post-induction, after sternotomy, and after extracorporeal circulation. An updated hematocrit was entered in the two-wavelength system preceding the last two measurements. Patient demographics, severity of preoperative cardiac disease, and intraoperative hemodynamics were comparable between groups. Two-wavelength determinations varied inconsistently from cooximeter values, while three-wavelength measurements did not differ significantly. Changes in hematocrit were responsible in part for the variability in two-wavelength measurements. In summary, three-wavelength measurements by the Shaw system were more accurate than two-wavelength measurements by the Edwards system.

Aged↗

PubMed1989

Acinetobacter peritonitis during chronic peritoneal dialysis.

Among gram-negative bacilli isolated during peritonitis in chronic peritoneal dialysis (CPD), Pseudomonas species are most common but Acinetobacter species are nearly as frequent. A survey of more than 450 patient-years' experience with CPD revealed 23 episodes of Acinetobacter peritonitis (AP), making this the second most common form of gram-negative peritonitis. Concomitant break in sterile technique and exit-site/tunnel infection were infrequent. AP appeared as the first peritonitis episode in five cases and as the second in six cases, and the duration of CPD at the time of AP ranged from less than 1 to greater than 56 months. However, AP was noted to appear shortly after treatment of another peritonitis episode or shortly after CPD access placement, within 2 months in 11 cases (47%) and within 3 months in 14 cases (61%). Treatment with intraperitoneal antibiotics succeeded in 21 cases (91%) without CPD interruption or catheter removal, with tobramycin or gentamicin alone in 16 cases, and with combined aminoglycoside and penicillin or cephalosporin in six cases. In two cases intraperitoneal antibiotics alone were insufficient therapy: one case with concomitant tunnel infection and dialysate leak and one case with bacteremia while receiving corticosteroids. The time-dependent incidence of AP suggests opportunistic infection during a vulnerable period in the first 2 to 3 months following another peritonitis episode, but AP also appears amenable to intraperitoneal antibiotic therapy alone without interruption of the CPD routine in the majority of cases.

Acinetobacter Infections↗