Search PubMed⌕ Search

Biomedical subjects

P Lozano

Publications and source records attributed to P Lozano.

At least 55 records · Page 3Linked to original sources
PubMed1995

[Medical evaluation of the climacteric patient].

A pilot program with primary care physicians was established in Clinica Cuauhtémoc y Famosa, focused to evaluate women older than 35 years with climateric symptoms. This program included a survey, a complete gynecological examination with Pap smears, ultrasound pelvic examination and mamography. Also, blood samples were collected for cholesterol, tryglycerides, calcium, phosphorus and alkaline phosphatase. An ECG, bone densitometry of the radius and X-rays of the vertebral column were obtained. This group was formed by 69 women with an age media of 50 years (SD 7.6 years, median 49 years). The survey disclosed that 34/65 women had been hysterectomized, and only 34/64 had received antitetanic immunization in the last 10 years. A preexistent chronic disease occurred in 36/59 women, these were diabetes mellitus, arterial hypertension or degenerative osteoarthritis. Alcohol consumption was recorded in 5/66 women and tabac consumption in 9/66 women, and 32/68 women accepted to be sedentary. Laboratory examinations disclosed hypercholesterolemia in 19/66 women and hypertryglyceridemia in 8/64 women. Osteopenia was detected in 33/60 women. This findings support a systematic plan to provide medical assistance for women in this age, specially if previous epidemiologycal studies have disclosed that coronary disease is the main cause of death for women older than 50 years in this region, that also belongs to the area of highest incidence of diabetes.

Alcohol Drinking↗
PubMed1995

Ruptured aneurysms of the internal iliac artery. Report of two cases.

Solitary internal iliac artery aneurysms are very rare. Their localisation deep in the pelvis makes diagnosis difficult. Therefore they are not detected until they reach a significant size and produce symptoms. These symptoms are due to compression on the adjacent structures or their rupture. Duplex scan, computerized tomography, and arteriography are the most useful diagnostic procedures. The correct surgical therapy consists of the ligature of the internal iliac artery and endoaneurysmorraphy with obliteration of the tributary branches. We report herein two cases of aneurysms of the internal iliac artery that made their clinical debut with signs of rupture.

Aged↗
PubMed1994

Effect of polyols on alpha-chymotrypsin thermostability: a mechanistic analysis of the enzyme stabilization.

The influence of the synthetic substrate (N-acetyl-L-tyrosine ethyl ester) and the different polyols (ethylene glycol, glycerol, erythritol, xylitol and sorbitol) on the thermostability of alpha-chymotrypsin at 60 degrees C have been studied. The results obtained showed an important stabilizing effect in the presence of both additives. In order to describe the kinetics of enzyme stabilization, the experimental results were analyzed by a four-parameters deactivation model with excellent agreement. In all cases, alpha-chymotrypsin exhibited non-first-order deactivation kinetics, corresponding to a two-step unimolecular mechanism, where the main protective effect of polyols was observed in the first-step of the deactivation profile. Thus, the presence of polyols increased the level of activity stabilization (alpha 1), and decreased the first-order deactivation rate constant (k1). Additionally, the experimental results were analyzed as a function of both, the change in the standard free energy of denaturation (delta(delta Gzero)), and a protective effect, defined as the ratio of alpha-chymotrypsin half-lives (with and without polyols), showing in both cases a clear stabilizing effect of these polyhydroxylic cosolvents for the enzyme. The overall protective effect of polyols was also simultaneously related to their concentration and their water-activity depressing power.

Chymotrypsin↗
PubMed1994

Acute lower limb ischemia complicating endocarditis due to Candida parapsilosis in a drug abuser.

Acute ischemia due to arterial embolism occurred in the right leg of a male drug abuser who had developed fungal endocarditis as a result of Candida parapsilosis. Transesophageal echocardiography aided in the diagnosis. The patient was successfully treated with fibrinolysis and surgery. The clinical features and management of this serious condition have been reviewed in the literature.

Acute Disease↗
PubMed1994

Comparison of thymoxamine permeation between hairless rat and horse penile mucous membrane using an in vitro diffusion model.

Moxisylyte (or thymoxamine) administered intracavernously is known to improve erection in organically impotent patients. Prior to drug administration by percutaneous route, we have to define its in vitro permeation parameters after application of thymoxamine on both rat skin and horse penile mucous membrane. 24 h after drug application, the percentages of thymoxamine which diffused through the penile mucous and the rat skin were 88 and 75%, respectively. Thymoxamine flux varied according to the biological membrane tested. With regard to the penile mucous membrane, a maximal flux (1,774 nmol.h-1.cm-2) was observed 2.5 h after drug application, whereas for the rat skin a maximal flux (657 nmol.h-1.cm-2) was noted at 3.5 h. Thymoxamine flux decreased rapidly in the penile mucous membrane. This decrease was slower when thymoxamine penetrated the rat skin; the difference could be due to a different morphology of the tested biological membranes. In contrast to the rat skin, the external keratinized layer was absent in the penile mucous membrane. In conclusion, the ability of thymoxamine to penetrate easily and rapidly the biological membrane, and particularly the penile mucous membrane, suggests that thymoxamine could reach the pharmacological target represented by the corpus cavernosum of the penis.

Animals↗
PubMed1994

Advocacy training during pediatric residency.

Despite broad concerns about the welfare of children, most pediatric residents are not able to engage in child advocacy during their busy training years. Yet residency can provide an opportunity for young pediatricians to learn valuable advocacy skills by undertaking an independent project with an experienced mentor. We describe the University of Washington Pediatrics Residency Program's experience in training interested residents in child advocacy. Basic requirements are that advocacy projects must not interfere with clinical training, resident participation must be voluntary, and faculty with advocacy skills must be available to help guide the residents. Four resident projects are outlined and guidelines for instituting such programs are presented.

Child↗
PubMed1994

Cryo-enzymatic synthesis of kyotorphin in saline environments.

The effect of six different alkali halides (LiCl, NaCl, KCl, LiBr, NaBr and KBr) on kyotorphin ethyl ester synthesis catalyzed by alpha-chymotrypsin has been studied in aqueous media at low temperature (3 degrees C). The results showed an enhancement on the synthetic activity of the enzyme by the presence of salts, proportionally to salt concentration. Water activity was shown as a key parameter in the control of the enzyme synthetic action in the saline media, being the influence of the assayed salts independent of the nature of ions. In all cases, the decrease in the reaction temperature to subzero values (-20 degrees C) reported a proportional increase in the selectivity of the peptide synthesis reaction.

Analgesics↗
PubMed1994

[Aneurysm of the celiac trunk associated with infrarenal aortic and popliteal artery aneurysm].

Intestinal artery aneurysms are usually asymptomatic; however when rupture occurs, mortality rates of up to 75% have been reported. Celiac artery aneurysms are quite infrequent, only about 4% of all visceral aneurysms; their association with Aortic Aneurysms is found in 18% of cases; their association with popliteal aneurysms has not been documented so far. A case of an adult male with celiac artery aneurysm associated with Aortic and Popliteal Aneurysms is reported. The patient was operated. In a first procedure the celiac and aortic aneurysms were resected, an aortic graft was placed, and hepatic artery reimplantation was performed; in a second procedure the popliteal artery was resected and a vascular reconstruction performed. The postoperative course was uneventful, and the patient remains asymptomatic two years later. Diagnosis was based on a CT scan with selective visceral angiography. Elective surgical intervention must be performed when intestinal artery aneurysms are discovered.

Aneurysm↗
PubMed1993

Influence of polyhydroxylic cosolvents on papain thermostability.

Papain thermostability was studied, and non-first-order deactivation kinetics were observed. The results obtained were analyzed by a two-step series-type deactivation model involving the native and active enzyme, an active intermediate enzyme state, and a final inactive state, with excellent agreement. The influence of different polyhydroxylic cosolvents (ethylene glycol, glycerol, erythritol, xylitol and sorbitol) on the thermostability of papain at 60 degrees C was also studied. Analysis of the results by the assayed model showed that the main protective effect of cosolvents was observed in the second step of the deactivation profile. The results obtained were analyzed as a function of both the thermodynamic parameters and a protective effect, defined as the ratio of papain half-lives (with and without cosolvents) for the second deactivation step, showing in both cases an important stabilizing effect of these cosolvents on the enzyme. The overall protective effect of cosolvents was also related simultaneously to their concentration and their water activity-depressing power.

Biotechnology↗
PubMed1993

Glycylglycylphenylalaninamide synthesis catalysed by papain in a medium containing polyols.

The influence of several polyols (ethylene glycol, glycerol, erythritol, xylitol and sorbitol) on both the thermostability and tripeptide(Gly-Gly-PheNH2)-synthesis capability of papain was studied at 60 degrees C. The results obtained from the thermostability studies on papain showed that polyols increased the half-life time of the esterase activity of the enzyme proportionally to their molecular size and concentration, except for ethylene glycol. The presence of polyols, as water-activity-depressing agents, also enhanced the enzyme activity for Gly-Gly-PheNH2 synthesis in a way which was directly proportional to the molecular size of the polyol molecule and its water-activity-depressing power. A linear relationship between the increase in the synthetic/hydrolytic activity ratio and the overall concentration of hydroxy groups in the reaction media was obtained, indicating that these latter groups are mainly responsible for the modification of the catalytic behaviour of the enzyme, as a result of a change in their microenvironment.

Amino Acid Sequence↗
PubMed1991

alpha-Chymotrypsin in plastein synthesis: influence of substrate concentration on enzyme activity.

The role of alpha-chymotrypsin in the plastein reaction was studied using a peptic hydrolysate of albumin as substrate. Study of this reaction simultaneously by different methods showed that the plastein reaction is enzyme catalyzed and is highly dependent on environmental conditions. A gel permeation chromatography study of the plastein reaction showed simultaneous increases in the high- and low-molecular-weight oligopeptide fractions; a transpeptidation mechanism may be involved in the reaction. A study of the effect of substrate concentration on the plastein reaction catalyzed by alpha-chymotrypsin showed a profile with both hydrolytic and synthetic activities. This effect was also observed when the reaction course was followed by quantification of the free amino groups at different substrate concentrations, showing that a condensation mechanism is responsible for the synthetic activity when the substrate concentration is very high. These results have led us to conclude that the plastein reaction involves a transpeptidation and/or condensation mechanism, which is a function of the substrate concentration.

Albumins↗
PubMed1990

Kinetic and operational study of a cross-flow reactor with immobilized pectolytic enzymes.

The kinetics and operational behavior of a nylon membrane derivative with immobilized pectolytic enzymes in a cross-flow reactor were analyzed. A high dependence on the recycling flow rate was observed. A design equation of the system has been proposed by taking into account both the shear stress deactivation and the control of the external diffusional limitations. Integration of the resulting design equation allowed us to study the effect of different operational parameters on substrate conversion. The catalytic efficiency of the immobilized derivative in a cross-flow reactor showed the highest pectin hydrolysis capability when it was compared with two different configurations of packed-bed reactors.

Enzymes, Immobilized↗
PubMed1990

Vancomycin-resistant Pediococcus acidilactici: nine cases of bacteremia.

Pediococci, vancomycin-resistant gram-positive cocci, have been isolated from human specimens, but an association with clinical illness has not been established. Clinical and epidemiologic data were obtained on nine patients who had Pediococcus acidilactici isolated from blood. Patients were eight elderly adults with complicated medical problems and one infant with congenital jejunoileal atresia. Seven patients were hospitalized before P. acidilactici was isolated. Eight had received multiple antibiotics; however, only two had received vancomycin. In all cases there was a delay in correct bacterial identification, and the significance of the isolate was uncertain. There was no clearly identified syndrome associated with P. acidilactici bacteremia. All eight adults had fever and six had pneumonia potentially attributable to other causes. The findings underscore the importance of proper identification of vancomycin-resistant gram-positive cocci. P. acidilactici may be an opportunistic pathogen in severely compromised hosts; however, further observations are necessary to clarify its role in human disease.

Aged↗
PubMed1986

Embolization of the mesenteric arteries: surgical treatment in twenty-three consecutive cases.

Twenty-three patients with acute embolization of the superior mesenteric artery are presented. Twenty-one of them presented with sudden abdominal pain but no other remarkable physical findings. One had diffuse abdominal pain while one did not have any abdominal pain. Twenty-two patients underwent direct surgical revascularization and one patient refused operation. The total mortality in this series was 27%. Eighteen patients underwent revascularization without resection and 15 of them (83%) survived. Early diagnosis is the key to improved results in acute mesenteric ischemia. It relies on the aggressive utilization of arteriography to identify patients with superior mesenteric artery embolization before intestinal infarction takes place.

Aged↗
PubMedDate not supplied

[Clinical management in an angiology and vascular surgery unit. Results of the application of a clinical practice protocols].

OBJECTIVES: The aim of this study was to analyze the impact of clinical management on quality indicators in a vascular surgery unit over a 10-year period. METHODS: We performed a retrospective analysis of quality indicators from 1990 to 2001 and of the influence of a clinical practice protocol and standards of quality on these indicators. RESULTS: Comparison of both periods revealed improvement in all the quality indicators. The safety of surgical procedures was unaffected by the application of management protocols and clinical pathways. CONCLUSIONS: Clinical management based on the cost-quality binomial can ensure the efficiency of a hospital unit without adversely affecting quality of care. Quality standards based on hospital resource use, morbidity and mortality can be defined for groups of procedures.

Algorithms↗
PubMedDate not supplied

Chronic care costs in managed care.

This DataWatch presents estimates of the health care costs for all adults who were continuously enrolled in a large staff-model health maintenance organization (HMO) during 1992. More than one-third of these adults were diagnosed with at least one chronic condition in 1992, and costs for this population are at least twice those of the population without chronic conditions. A diagnosis of a chronic condition results in an expected increase in costs of 80 percent-300 percent, depending on age, sex, and chronic condition profile. Previous studies of the costs of chronic illness have focused on the fee-for-service sector. As managed care continues to grow, it is important that economic analyses focus on this market segment.

Adult↗
PubMedDate not supplied

[Verbal fluency and Alzheimer's disease].

UNLABELLED: BASIC: The loss of verbal fluency in Alzheimer's disease (AD) has been related to the cognitive and functional impairment caused by the disorder. GOALS: To determine the value of the different types of verbal fluency examination for the detection of AD. MATERIAL AND METHODS: We have compared the results obtained in the study of verbal fluency in 74 patients with probable AD (NINCDS-ARDRA criteria) to a control group of 64 persons of similar age, gender and educational level. Patients were divided in three categories according to the intensity of dementia: very mild (MMSE > 23), mild (MMSE 18-23) and moderate (MMSE 10-17). Semantic and literal verbal fluencies were studied by means of the "set-test", including in the analysis the results in every of four categories and total, the time consumed per category and the sum of all, the number of animal's names and words given in a minute. We also determined the number of animals in every fifteen seconds up to one minute in 66 controls y 97 patients. Results in the different groups were compared using the ANOVA variance and the contrast of means for alpha < or = 0.05. CONCLUSIONS: The time consumed in saying the names has a great value in detecting AD, with the same or even better significance than the number of words. It is feasible to shorten the examination and use only one category of names. Our results suggest that counting the names of animals given in the first fifteen seconds does not lower the value of the exam and can also suppress a "roof effect" of the test. A short version of semantic verbal fluency examination could be of potential use in general practice where time consuming exams are difficult to implement.

Aged↗