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Biomedical subjects

C P Larson

Publications and source records attributed to C P Larson.

At least 19 recordsLinked to original sources
PubMed1995

Urban to rural routes of HIV infection spread in Ethiopia.

A descriptive survey to identify routes of spread of HIV infection from urban to rural populations was carried out in a rural south-central Ethiopian district. High risk practices for HIV infection and transmission were first documented among rural residing former soldiers, merchants and students. Extramarital intercourse during the previous 3 months was reported by 45-50% of these subgroups. In 25-37%, intercourse with an urban commercial sex worker (CSW) was reported and condom use varied from 10 to 30% among subgroups. The perceived risk for AIDS was low and changes in risk behaviours were minimal. Next, 502 rural males farmers were surveyed. An extramarital sexual contact in the past 3 months was reported by 13.5%, with 7% reporting their most recent contact with an urban CSW. Only 6% of farmers reported using condoms. Awareness of AIDS was reported by 59% and, of these, only 28% perceived they were vulnerable. In this study increased knowledge was associated with more frequent high risk sexual practices. It is concluded that the spread of AIDS into rural communities is occurring as a result of the high frequency of high risk sexual behaviours in specific rural residing subgroups which frequently travel into urban communities in combination with a low background prevalence of high risk practices among the general male farmer population.

Adolescent↗
PubMed1994

Multisite evaluation of a continuous intraarterial blood gas monitoring system.

BACKGROUND: We compared the performance of a new, continuous intraarterial blood gas (CIABG) monitor with arterial values obtained periodically and analyzed by conventional equipment. METHODS: A CIABG monitoring system consisting of a sterile, disposable, fiberoptic sensor and a microprocessor-controlled monitor with a self-contained calibration unit and detachable display panel was used. The sensor was inserted through a 20-G radial artery cannula. Light was transmitted from the monitor to the sensor tip where it reacted with fluorescent dyes sensitive to oxygen or hydrogen ions (analytes). The change in the intensity of the photoluminescent radiation caused by the analytes was measured every 20 s and derived blood gas values were displayed. Twenty-nine sensors were evaluated in 29 surgical or intensive care unit patients at one of three institutions (Stanford University Hospital, Evanston Memorial Hospital, and the Palo Alto Veterans Administration Hospital). The duration of study averaged 6 h (5-8 h) in the operating room, and 46 h (7-121 h) in the intensive care unit. A total of 552 values were compared with those obtained at regular intervals and analyzed in the hospital blood gas laboratory. Average bias (mean difference between lab value and CIABG), precision (SD of difference), and drift (change in the bias with time were determined. RESULTS: At arterial oxygen tension (PO2) values of 32-528 mmHg, the average bias was -1% meaning that the average CIABG monitor values were 1% lower than those obtained by conventional equipment. The precision was 15%. At arterial PO2 values of 32-99 mmHg, average bias and precision were -0.3 +/- 8.9 mmHg. At arterial carbon dioxide tension (PCO2) values of 24-54 mmHg, average bias and precision were 1.3 +/- 3.3 mmHg, and at pHa values of 7.23-7.57, average bias and precision were 0.01 +/- 0.04. Observed drift per day was -1.2% for arterial PO2, 0.3 mmHg for arterial PCO2, and 0.01 for pH. Bias and precision for samples compared in two pairs of like-model in vitro blood gas analyzers were 0.4 +/- 4.6% for arterial PO2 over the full range, and 0.4 +/- 3.7 mmHg for values less than 100 mmHg, -0.5 +/- 1.8 mmHg for arterial PCO2, and 0.01 +/- 0.01 for pHa. Although the occasional marked discrepancies between one or more CIABG and in vitro values could sometimes be corrected by flushing the arterial catheter or repositioning the sensor, usually we could not determine the cause of the discrepancy or which values were the more accurate. CONCLUSIONS: Over the range of values and under the clinical conditions studied, CIABG monitoring provides immediate blood gas results and trend information with sufficient agreement with in vitro results to be reliable for decision making in most clinical circumstances. Generally, the differences in the values between the two methods of analysis were the result of the combination of the inherent errors of each method. Additional studies need to be undertaken to evaluate the performance of the CIABG monitor across wider ranges of blood gas values, especially for arterial PO2 values less than 60 mmHg and arterial PCO2 values greater than 50 mmHg.

Adult↗
PubMed1993

A community-based randomized trial of home-made oral rehydration therapies.

A field trial of the relative efficacy of three oral rehydration therapies (ORT) in the treatment of acute childhood diarrhoea in children < 5 years old was carried out in a rural Ethiopian district. The three ORT were 1) pre-packaged glucose and salt solution (GORS; n = 153), 2) home-made cereal added to pre-packaged salt solution (CBORS; n = 154), and 3) entirely home-made cereal-based and salt therapy (CBORT; n = 156). Out of 127 eligible peasant associations, 18 were randomly selected, and groups of six were then randomly assigned to receive one of the three treatment options. In infants aged 0-12 months, after adjusting for baseline weight and diarrhoea frequency, CBORT was found to be superior (P < 0.01) to GORS and CBORS in terms of weight gain at 24, 48, and 96 hours. There were no significant between-group differences in weight gain in children > 12 months old. Over the 96-hour duration of follow-up, mothers' compliance was significantly better among those giving CBORT when compared to CBORS (P < 0.001) or GORS (P < 0.013). The results of this field trial indicate that CBORT is an efficacious alternative to GORS or CBORS in the treatment of acute childhood diarrhoea in rural community settings. Larger scale, effectiveness studies are recommended.

Child, Preschool↗
PubMed1993

Modern contraception use in Ethiopia: does involving husbands make a difference?

OBJECTIVES: This study was undertaken to determine the relative efficacy of home visitation with and without husband participation on the use of modern contraception in Ethiopia. METHODS: A randomized field trial of a family planning education intervention using home visitation with and without husband participation was conducted in Addis Ababa, Ethiopia, from August 1990 to December 1991 and included a 12-month postintervention follow-up. A total of 266 experimental and 261 control subjects were entered, of whom 91.7% and 88.9%, respectively, were followed through 12 months. RESULTS: A greater proportion of couples in the experimental group were practicing modern contraception at 2 months (25% vs 15%) and 12 months (33% vs 17%) following the home visit intervention. By 12 months following the home visits, experimental subjects were less likely to have defaulted and more likely to have started using modern contraception following an initial delay. CONCLUSIONS: The inclusion of husbands in family planning programs will result in relevant increases in the use of modern contraception. However, there exists an important "sleeper" effect to the education intervention, reflected by a delay of greater than 2 months in the initiation of modern contraception for most couples.

Adult↗
PubMed1991

Determinants of mental illness in a rural Ethiopian adult population.

A cross-sectional survey was conducted on 2000 adult Ethiopians living in rural communities to determine firstly the prevalence of mental illness and secondly its association with stress and demographic variables. The Self-Reporting Questionnaire developed by WHO experts was used as the measure of mental illness. A modified version of the Holmes-Rahe Social Readjustment Scale was the measure of stress. Respondents were interviewed in their homes. Those experiencing 11 or more of the 20 neurotic symptoms and 3 or more of the 4 psychotic symptoms were considered mentally ill. Despite the use of high cut-off points for identifying potential cases, the prevalence of mental illness was 17.2%--neurotic 11.2% and psychotic 6.0%. This is higher than earlier reports for Ethiopia, but comparable to rates found in other African countries. Mental illness scores were most strongly associated with stress in that the odds of experiencing 6 or more stressful life events in the past year were 2.7 times greater for neurotics and 2.1 times greater for psychotics. In addition, neuroses and psychoses were significantly associated with a family history of mental illness and with being divorced, separated or widowed. Neurosis alone was also associated with chronic illness, females, those between the ages of 35 and 44, and illiteracy. These findings were discussed in terms of their relevance for identifying high stress groups and thus for preventing mental illness through community activities.

Adolescent↗
PubMed1991

The occurrence and driver characteristics associated with motor vehicle injuries in Addis Ababa, Ethiopia.

Ethiopian documentation of the occurrence and determinants of motor vehicle related morbidity and mortality is sparse. The purpose of this investigation was to determine the incidence of hospital treated motor vehicle injuries (MVI) in Addis Ababa and driver characteristics associated with involvement in a MVI. The study was conducted over a 12-week period in the autumn of 1988. Over 91% of MVI involved pedestrians. The overall MVI incidence density rate was 279.4 per 100,000 person years and the mortality rate was 17.6 per 100,000 population per year. Road accident injury and fatality rates were 946 and 59.5 respectively per 10,000 registered vehicles. Overall years of person life lost was 595 per 100,000 person-years exposure. Significantly increased odds of exposure among drivers inflicting a MVI were found for younger age, fewer years driving experience, male gender, and those driving newer, government owned, and mass transit vehicles.

Accidents, Traffic↗
PubMed1990

Effect of hyperglycemia on neuronal changes in a rabbit model of focal cerebral ischemia.

In clinical medicine, cerebral ischemia is frequently due to a focal, rather than global, insult. The effect of hyperglycemia in focal cerebral ischemia is not well defined. We studied the effect of hyperglycemia on neuropathologic changes in a rabbit model of focal cerebral ischemia. Rabbits were randomized to receive saline (n = 12) or glucose (n = 12) infusions. The left anterior cerebral and left internal carotid arteries were clipped after the infusion began. After 6 hours of occlusion, the area of severe ischemic neuronal damage in the left neocortex and striatum on two standard sections of brain was calculated and expressed as a percentage of the total area of the left cortex or striatum. The mean +/- SEM cortical area of severe ischemic neuronal damage was 22.1 +/- 2.8% in the glucose-treated rabbits and 34.0 +/- 4.6% in the saline-treated rabbits (p less than 0.05). The cortical area of severe ischemic neuronal damage was inversely correlated with plasma glucose concentration at the time of arterial clipping (p less than 0.05). We conclude that hyperglycemia is associated with decreased histologic neuronal injury in this model of focal cerebral ischemia and may be protective when cerebral ischemia occurs from a focal insult.

Animals↗
PubMed1990

Neuropathologic observations in congenital phrenic nerve palsy.

A right phrenic nerve palsy with severe respiratory and feeding difficulties throughout the patient's 2 1/2 years of survival was found at autopsy to relate to grossly complete atrophy of the muscle of the right diaphragm. An oblique fibrotic scar transected the right phrenic nerve at the level of the brachial plexus. There was marked reduction of the number of anterior motor neurons in the right central portion of cervical segments 2, 3, and 4. The lesion in the phrenic nerve is what would be expected following stretching during delivery.

Birth Injuries↗
PubMed1989

Hyperglycemia decreases acute neuronal ischemic changes after middle cerebral artery occlusion in cats.

Hyperglycemia has been reported to worsen the tolerance of the brain to ischemia, and it has therefore been recommended that patients undergoing neurosurgical procedures not receive glucose-containing solutions. However, whereas most animal studies have used global ischemia models, most neurosurgical procedures are associated with risks of focal rather than global ischemia. We therefore studied the effects of glucose administration in an animal model of focal cerebral ischemia. We anesthetized 20 cats with halothane (0.85% end tidal in oxygen), and a focal cerebral ischemic lesion was produced by clip ligation of the left middle cerebral artery using a transorbital approach. Hyperglycemia (10 cats, mean +/- SEM plasma glucose concentration 561 +/- 36 mg/dl) was established before ligation by infusion of 50% glucose in 0.45% saline; the control group (10 cats, mean +/- SEM plasma glucose concentration 209 +/- 28 mg/dl) received 0.45% saline only. Total fluid administered, mean arterial blood pressure, body temperature, and arterial blood gas values did not differ between the two groups 0, 2, and 6 hours after ligation. The cats were killed 6 hours after ligation, and the area of severe ischemic neuronal damage was determined by microscopic examination of a coronal section at the level of the optic chiasm. The mean +/- SEM area of left cortical severe ischemic neuronal damage was 12 +/- 2% of the left cortex in the hyperglycemic group compared with 28 +/- 5% in the control group (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1988

Risk factors for injury in a 3-year-old birth cohort.

The purpose of this study was to identify factors associated with injuries in the first three years of life and to assess their predictive utility. The parents of 918 children (82% of an eligible birth cohort) completed a telephone interview to document injury histories. The occurrence of injury was then linked to previously obtained information characterizing early childhood. Several determinant associations were found for injuries seen by a physician and for those requiring treatment. Maternal factors (single, unemployed, smoking) were dominant in both instances. From these factors, logistic regression models were developed from which adjusted relative risk estimates were derived. The presence of all three maternal factors, as well as the absence of a younger sibling, increases the probability of an injury from 20% to over 60%. These findings may be used to assist in the development of preventive programs by targeting children at increased risk. They also provide a basis for further studies that will permit a better understanding of the causal mechanisms linking maternal factors to preschool injury.

Adult↗
PubMed1988

Preschool behavior disorders: their prevalence in relation to determinants.

The occurrence of behavior disorders was investigated in a prospectively followed 3-year-old birth cohort. Of 1116 eligible children, the parents of 918 were successfully contacted. All agreed to complete a telephone interview and were mailed a Childhood Behavior Checklist (CBCL) standardized for 2- to 3-year-old children; 756 (82%) returned the CBCL. The prevalence of one or more of the deviant behavior syndromes identified by the CBCL was 11.1%. From a number of subject characteristics recorded throughout infancy, age-specific determinants for the occurrence of these deviant behaviors were identified. Characteristics most consistently associated with preschool psychopathology included the mother's ill health and lack of social support, the presence of chronic illness in the child, and the frequent use of hospital emergency services. These and other determinant (risk) indicators were entered into logistic regression (LR) models to derived adjusted relative risk estimates for the occurrence of a behavior disorder. The derived LR equations emphasize the important role of both the mother as well and the father and the health of the child.

Affective Symptoms↗
PubMed1988

PEEP does not affect left atrial-right atrial pressure difference in neurosurgical patients.

Positive end-expiratory pressure (PEEP) has been used to prevent and treat venous air embolism in patients in the seated position undergoing neurosurgical operations. However, the safety of PEEP has recently been questioned, because of concern that PEEP might increase right atrial pressure (RAP) more than left atrial pressure, thereby predisposing patients with a probe-patent foramen ovale to paradoxical air embolism. In a prior study in dogs, the authors found that to up 10 cm H2O PEEP did not affect the interatrial pressure difference. In the present study, the authors examined the effects of 0, 5, and 10 cm H2O PEEP in 12 anesthetized neurosurgical patients positioned both supine and seated prior to operation. Measurements were made of systemic arterial pressure, RAP, mean pulmonary artery pressure (PAP), pulmonary artery wedge pressure (PAWP), and cardiac output. PAWP was higher (average 2 mmHg) than RAP in all patients. PEEP increased RAP and PAWP in patients, both seated and supine (mean 3 mmHg at 10 cm H2O), but did not affect the PAWP-RAP difference. In an additional eight patients in the seated position, the authors examined the effects of 0, 10, and 20 cm H2O PEEP during operation. PEEP again increased PAWP and RAP, but did not significantly affect the PAWP-RAP difference. The PAWP-RAP difference became negative (-1 mmHg) in one patient with 20 cm H2O PEEP. The authors conclude that levels of PEEP up to 10 cm H2O do not alter the interatrial pressure difference in seated neurosurgical patients, and, therefore, would not predispose these patients to paradoxical air embolism.

Adult↗