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Biomedical subjects

P Rojas

Publications and source records attributed to P Rojas.

At least 55 records · Page 3Linked to original sources
PubMed1991

Adolescent pregnancy: maternal weight effects on fetal heaviness: possible route to improved outcomes.

In a previous report of a zinc supplementation trial in pregnant adolescents zinc effect varied according to maternal weight (wt) status--normal (90-110% of expected wt), light or heavy, prompting this analysis of effects of wt status and gestational wt gain on fetal heaviness relative to length and gestational age (GA) and other pregnancy outcomes. One-third of adolescents shifted in or out of normal wt by delivery, creating seven outcome groups--light-light, light to normal, normal to light, normal-normal, normal to heavy, heavy to normal, and heavy-heavy. These wt class change groups varied significantly as to intrauterine growth (SGA, low AGA, high AGA, and LGA); by weekly grams gain per cm height (ht), birth wt, infant wt/length ratio, and occurrence of low birth wt (LBW). Infants with above average intrauterine growth had an advantage in: absolute size, length of hospital stay, rates of LBW, fetal demise, rates of low Apgar score, and "other" complications. This association between intrauterine growth and maternal wt class change suggests that promotion of wt gain might lower rates of LBW. Birthwt varied by quartiles of weekly wt change (gm) per cm ht in women grouped by their percent of expected wt: in the lowest quartile (Q1) only one group in seven reached average Bwt (3025 grams); with Q4 gain all groups did. Thus, the parameter wt gain/wk/cm ht deserves study as a tool for monitoring wt status and gain to identify those pregnant adolescents in greatest need for nutritional counseling and to set wt gain goals.

Adolescent↗
PubMed1990

Nurses bring primary health care to industrial workers.

Progress in bringing health care to the workplace lags considerably behind progress in bringing health care to where people live. Experience in Botswana shows that the family nurse practitioner--a registered nurse midwife with one year of post-basic training--can provide useful preventive and curative services to people in their places of work.

Botswana↗
PubMed1989

Adolescent pregnancy: associations among body weight, zinc nutriture, and pregnancy outcome.

In a double-blind zinc trial in low-income, pregnant adolescents thought to be at risk for poor zinc nutriture, subjects were randomly assigned to receive 30 mg zinc (gluconate) or placebo. Response to zinc was related to maternal weight. Infants of normal-weight mothers given zinc had reduced rates of prematurity (p = 0.05) and assisted respiration (p = 0.006). Underweight multiparas given zinc had longer gestational lengths (p = 0.008) than did subjects given the placebo. Multiple stepwise regression analysis, used to identify predictors of infant size, revealed that 14-26% more variance was accounted for in the zinc than in the placebo group. Except for gestational age, the predictors selected were entirely different in the two groups. The zinc group had a positive toxemia screen more often, which did not appear to affect outcome. Zinc supplementation improved pregnancy outcome in normal-weight women and in underweight multiparas. The nonresponse in underweight primiparas was perhaps due to multiple limiting factors.

Adolescent↗
PubMed1986

Fundus lesions in malignant hypertension. III. Arterial blood pressure, biochemical, and fundus changes.

Malignant (accelerated) renovascular arterial hypertension was produced in 57 adult rhesus monkeys by clamping the renal artery (one-kidney model in 25 animals and two-kidney model in 32). The animals were investigated before renal artery clamping and serially thereafter by recording systolic arterial blood pressure (BP), biochemical changes, and changes in the fundus of the eye; the latter was evaluated by ophthalmoscopy, stereoscopic color fundus photography, and fluorescein fundus angiography. All of the animals developed arterial hypertension. The data on BP, biochemical, and fundus findings were analyzed and correlated. The findings of this study clearly showed that the various fundus lesions seen in these hypertensive animals fall into three distinct categories: (1) hypertensive retinopathy, (2) hypertensive choroidopathy, and (3) hypertensive optic neuropathy. The appearance of the retinopathy was significantly earlier than that of the choroidopathy or optic neuropathy (P less than 0.01), but the difference between the times of appearance of the choroidopathy and neuropathy was not significant. There was no significance in the order in which the three types of fundus changes reached their maximum severity. There was no significant difference between the mean BPs when the retinopathy, choroidopathy, or optic neuropathy first appeared, nor between the BPs at the time of their appearance and at the time when they were most marked. In monkeys of the one-kidney model, the rise in BP developed significantly (P = 0.01) faster and the fundus lesions appeared significantly (P = 0.00001) earlier than in those with the two-kidney model.

Animals↗
PubMed1986

Interocular differences of the visual field in normal subjects.

One way of judging if a visual field is abnormal, particularly when a patient has unilateral or asymmetric disease, is to compare the suspicious visual field to that of the normal eye. This assumes that in normal individuals the two visual fields are symmetrical. To determine the extent of normal symmetry, the authors examined the central visual fields of both eyes of 20 normal subjects with program 30-2 of the Humphrey perimeter. The inter-ocular sensitivity difference at single pairs of locations ranged from 0 to 9 decibels with large differences occurring most frequently in the upper field. Confidence intervals constructed from this set of normal data predict that asymmetry exceeding 6 decibels should occur in fewer than 1% of test locations and that asymmetry of overall mean sensitivity exceeding 1.4 decibels should occur in fewer than 1% of normal subjects.

Adult↗
PubMed1985

[Effect of a serum inhibitor on hematopoiesis regulation: in vitro effect on RNA synthesis in bone marrows of rats].

Hematopoiesis is regulated by several hormones and protein factors, among them, erytropoietin (Ep) and granulopoietin (CSF: Colony Stimulating Factor) play the fundamental control activities inducing the differentiation of stem cells to red and white cells series, respectively. The action of serum inhibitors and cyclic nucleotides on hematopoietic process is not well understood at present time. In this work a rat serum-inhibiting activity was detected that diminished the in vitro [3H] uridine incorporation into rat bone marrow whole RNA. The experiments show that the inhibitory may have a platelet origin.

Animals↗
PubMed1983

Ocular neovascularization with retinal vascular occlusion-III. Incidence of ocular neovascularization with retinal vein occlusion.

A prospective natural history study was conducted in 721 eyes with various types of retinal vein occlusion (RVO) to determine the incidence of various types of ocular neovascularization (NV) and the factors that influence the development of ocular NV. The material was 360 eyes with central retinal vein occlusion (CRVO), 97 eyes with hemi-CRVO, and 264 eyes with branch retinal vein occlusion (BRVO); these cases were further subdivided into six groups for logical data analysis: nonischemic CRVO (venous stasis retinopathy-VSR, 282 eyes), ischemic CRVO (hemorrhagic retinopathy-HR, 78 eyes), hemi-VSR (66 eyes), hemi-HR (31 eyes), major BRVO (191 eyes) and macular BRVO (73 eyes). Ocular NV attributable to RVO was seen only in HR, hemi-HR, and major BRVO. In HR the anterior segment was the major site of NV, with iris and angle NV and neovascular glaucoma (NVG), while in hemi-HR and major BRVO the retina and optic disc were the major sites of NV. The principal factor influencing the development of ocular NV in RVO seems to be the severity and extent of retinal ischemia, while duration of follow-up since onset also plays an important role in determining the incidence of ocular NV. The findings and subject of ocular NV in RVO are discussed in detail along with a review of the pertinent literature.

Adult↗
PubMed1982

Mortality risk factors in patients treated by chronic hemodialysis. Report of the Diaphane collaborative study.

A survival analysis was applied to 1,453 patients treated between 1972 and 1978 in 33 French dialysis centers and prospectively followed up in the computerized Diaphane Dialysis Registry. 198 deaths (overall mortality = OM) were registered, of which 87 (43%) were secondary to cardiovascular complications (cardiovascular mortality = CVM). Risk factors for OM and CVM (p values less than 0.05) were age, male sex, nephroangiosclerosis or diabetic nephropathy as the primary renal disease, elevated systolic and diastolic blood pressure and two weekly dialysis rather then three. In contrast with the results observed for the general population, a high body mass index and elevated cholesterol, triglycerides and uric acid were not found to be associated with significantly increased CVM or OM. On the contrary, low body mass index (less than 20 kg/m2), low cholesterol (less than 4.5 mmol/l) and low mean predialysis blood urea (less than 4.6 mmol/l) were associated with increased OM and CVM, and more especially with high stroke mortality. Results for urea but not for cholesterol remain significant after adjustment for age, sex, weekly dialysis schedule and body mass index. They suggest that, in addition to elevated blood pressure, a poor nutritional state and/or low protein intake may be important factors for explaining the high cardiovascular mortality, particularly for strokes, observed in dialyzed patients.

Adolescent↗
PubMed1981

Traumatic colonic perforation. Review of 16 years' experience.

The surgical management of colon injuries in civilian practice requires individualization. Primary repair, either by debridement and suture or resection and anastomosis, is a safe method of management in selected cases and results in a shorter hospital stay, less morbidity and a complication rate that is no higher. In this series, over half of the colon injuries were managed in this way. Exteriorization and proximal colostomy are accepted methods of management, but possibly should be reserved for the more severely injured patient. The criteria for individualization are briefly summarized.

Adult↗
PubMed1979

[Society of Nephrology, Computer Technology Commission. Dialysis computer program. VI. - Survival and risk factors].

The sixth report of the "Diaphane Dialyse Informatique" Program concerns 2,518 adult patients (age 15 and over) treated by chronic hemodialysis or hemofiltration in 33 French dialysis centres between June 1972 and December 1978. 1) The number of centers participating to the program is progressively increasing. Overall duration of follow-up represents 4,192 patient-years, allowing precise evolutive studies of terminal renal failure treated by hemodialysis. 2) Mean age at start of treatment continues to increase. Among 709 patients who started treatment in 1977-1978, 8,8 p. 100 of men and 11 p. 100 of women were over 69 years old. 3) Patients with diabetic nephropathy represent 4,4 p. 100 of all patients dialyzed between 1972 and 1978 and 5,9 p. 100 of the patients starting treatment in 1977-1978. 4) The percentage of patients temporarily treated by peritoneal dialysis before hemodialysis decreases from 32,9 p. 100 in 1973-1974 to 15,9 p. 100 in 1977-1978. 5) In 1978, 65,3 p. 100 of patients are dialyzed 3 times a week with a mean weekly duration of 14,0 h for male and 12,9 for female. 73 p. 100 of the patients are dialyzed during the night. 6) Disposable parallel plate hemodialyzers (71,8 per cent of dialysis sessions in 1978) and hollow fiber hemodialyzers (11,6 per cent) progressively replace disposable coil dialyzers and non disposable Kiil dialyzers. 7) Transient hypotensive episodes during dialysis sessions remain the most frequent complications (21,7 per cent of sessions in 1978). Transient hypotensive episodes are more frequently observed with coils than with parallel plate hemodialyzers or with hollow fiber dialyzers. 8) Mean diastolic blood pressure (DBP) +/- SD is 101,9 +/- 21,7 mmHg at start of dialysis and 81,4 +/- 11,8 mmHg when dialysed. During the course of treatment 28,7 per cent of the patients receive long term antihypertensive treatment. In spite of dialysis and antihypertensive treatments 11 per cent of all patients followed up maintain DBP greater than or equal to 95 mmHg. 9) Viral hepatitis remain the most prominent infectious problem with 30 per cent of patients being chronic Hbs antigen carriers. 10) Annual death rate calculated in the 2,518 patients dialyzed between 1972 and 1978 (78/1000) is 12 times superior to the death rate of the French population, adjusted for sex and age to the dialysis population. 43,1 per cent of deaths are of cardiovascular origin. Risk factors for overall mortality are age, sex (male), existence of a vascular or diabetic nephropathy, twice weekly dialysis strategy, elevation of systolic or diastolic blood pressure during the course of dialysis treatment, hypocholesterolemia and to a lesser extent hypotriglyceridemia. On the contrary, hypercholesterolemia, hypertriglyceridemia and hyperuricemia do not appear as risk factors for overall mortality or cardiovascular mortality. These results plead for a perfect control of hypertension and to the extension of thrice weekly dialysis for the whole population of patients treated by maintenance hemodialysis.

Adolescent↗