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Biomedical subjects

M Guerrero

Publications and source records attributed to M Guerrero.

At least 37 records · Page 2Linked to original sources
PubMed2001

Wegener's granulomatosis presenting as subglottic stenosis.

Wegener's granulomatosis is an uncommon disease process that causes necrotizing vasculitis predominantly in the lungs, kidneys, and upper air-ways. Subglottic stenosis has been observed in up to 20% of patients with established diagnosis of Wegener's granulomatosis, but it is rarely the initial manifestation of the disease. This case report presents a patient with Wegener's granulomatosis who had subglottic stenosis as predominant initial manifestation, without signs of lung or kidney involvement. The diagnosis was unclear initially due to the absence of damage to these organs and to the nonspecificity of the initial biopsy findings. After stabilizing the patient, an elevated cytoplasmic pattern of antineutrophil cytoplasmic antibodies titer was obtained, which played an important role in the diagnostic process and led to a second biopsy that showed vasculitis. The patient had an excellent response to prednisone, methotrexate, and trimethoprim/sulfamethoxazole, but as with many such cases, she also required tracheo-laryngoplasty.

Journal Article↗
PubMed2001

Plasma beta-endorphin levels in obese and non-obese patients with polycystic ovary disease.

The aim of this study was to determine the influence of body weight on circulating plasma levels of beta-endorphin and insulin in women with polycystic ovary disease (PCOD), as well as the correlation between the plasma levels of beta-endorphin and insulin. One-hundred and sixty-seven consecutive subjects with PCOD were recruited, 117 of whom had normal weight (body mass index (BMI) < 25) while 50 were obese (BMI > 25). A venous blood sample was taken and plasma concentrations of beta-endorphin, insulin, gonadotropins, prolactin, progesterone, 17 beta-estradiol, estrone, androgens, dehydroepiandrosterone sulfate and sex hormone-binding globulin (SHBG) were measured. Mean beta-endorphin and insulin plasma levels were significantly higher (p < 0.05) in obese PCOD women than in non-obese ones. Correlation analysis showed a positive association between insulin and beta-endorphin, beta-endorphin and BMI (and weight), insulin and BMI (and weight), and a negative correlation was found between insulin and SHBG. A weak association was found between beta-endorphin and luteinizing hormone (LH) in peripheral plasma. Stratified and linear regression analysis showed that plasma beta-endorphin concentrations correlate more with BMI than with insulinemia.

Adolescent↗
PubMed2000

Antibodies to Borrelia burgdorferi in European populations.

We compared the antibodies to B. burgdorferi in three different populations in order to evaluate the diagnostic reliability of Lyme borreliosis serologic analysis. The subjects included 25 patients with Lyme borreliosis (Group 1); 50 patients with diseases of unknown cause, B. burgdorferi ELISA-positive in serum and without B. burgdorferi infection (Group 2); and 1,251 individuals without Lyme borreliosis (Group 3). All samples were tested for B. burgdorferi B31 and B. afzelii antigens using ELISA. The positive results of the ELISA B. burgdorferi B31 assay were confirmed with Western blot for the same strain. In Group 3, 162 (12.9%) patients were ELISA positive for B. burgdorferi B31, while only 6 (0.6%) patients had IgG ELISA antibodies to B afzelii. Bands in WB were detected in 104 (8.4%) of the Group 3 subjects. The bands found to be most reliable for the identification of strain B. burgdorferi B31 by IgG WB were those representing the 93, 39, 34, and 23-kDa proteins. Our results show that serologic diagnosis of Lyme borreliosis is far from clearly established. To date, the only reliable criteria are clinical ones correlated with laboratory evidence.

Adolescent↗
PubMed2000

Diagnosis of human caliciviruses by use of enzyme immunoassays.

The application of molecular technologies, such as the expression of viral proteins in baculovirus, has provided a powerful approach to the diagnosis of human calicivirus (HuCV) infections. The baculovirus-expressed HuCV capsid protein self-assembles into virus-like particles, providing excellent reagents for immunologic assays, such as enzyme immunoassays (EIAs). Following the expression of the capsid protein of Norwalk virus, the capsid proteins of 8 other HuCV strains have been expressed in baculovirus. The unlimited supply of baculovirus-produced reagents for HuCVs allows these EIAs to be applied in large-scale clinical and epidemiological studies. Both the antigen and antibody-detection EIAs are highly sensitive. The antigen-detection EIAs are highly specific, but the antibody-detection EIAs are more broadly reactive. This article reviews baculovirus expression techniques used to produce HuCV capsid antigens, development of EIAs using these antigens, and application of these EIAs in studies of HuCV infection and illness.

Animals↗
PubMed1999

Pneumonia in HIV-infected patients: a case-control survey of factors involved in risk and prevention.

OBJECTIVE: To assess the factors that increase or decrease the risk of pneumonia with particular attention to immunization with pneumococcal and influenza vaccines in a group of HIV-infected persons. DESIGN: A retrospective, case-control study based on information entered into a standard database and the medical record. SETTING: Patients attending a referral clinic specializing in AIDS/HIV care at a public hospital. PATIENTS: Among over 2000 subjects entered into a database in 8 years, 127 incidents of pneumonia were identified from the record. These cases were matched with 127 CD4 cell count matched, concurrent controls. INTERVENTIONS: None. MAIN OUTCOME MEASURE: The principal hypothesis was that chart review would find a decreased frequency of pneumococcal immunization in the pneumonia cases compared with matched controls. RESULTS: Pneumococcal immunization was associated with a reduction of the risk of pneumonia by nearly 70%. The effect was seen even when immunization was given with a CD4 cell count of less than 100/mm3. Injection drug users and African-Americans had a twofold increased risk of pneumonia. CONCLUSION: The study provides data to support the current recommendation for pneumococcal immunization of all HIV-infected persons. Although this conclusion could lead to renewed enthusiasm for increasing pneumococcal immunization rates in HIV-infected persons, it must be recognized that the study is observational and ascertainment bias cannot be excluded.

AIDS-Related Opportunistic Infections↗
PubMed1999

Circulating levels of immunoreactive beta-endorphin in polycystic ovary syndrome.

The plasma levels of beta-endorphin were studied in 64 women with polycystic ovarian disease (PCOD), from whom was selected a group of 23 women with normal weight and amenorrhea of < 36 days. On day 21, beta-endorphin levels were: mean 64.92 pg/ml; SD 37.32 pg/ml; 95% CI 48.38-81.47 pg/ml. It was also observed that their levels of opioid peptide were reduced, compared with women who had normal ovulatory cycles, both in the follicular phase (mean 70.93 pg/ml; SD 24.59 pg/ml; 95% CI 76.84-99.77 pg/ml) and luteal phase (mean 88.30 pg/ml; SD 31.80 pg/ml; 95% CI 76.84-99.77 pg/ml). The results were statistically significant (p < 0.05) for levels in PCOD patients compared with those of the luteal phase in women with normal ovulatory cycles. The decreased levels of beta-endorphin were negatively related to luteinizing hormone (LH) levels, which might explain the rise of LH levels in women with PCOD who control their weight and at the time of amenorrhea, although it is not clear if central opioid activity is reflected in the peripheral blood.

Adolescent↗
PubMed1999

Multimodality stereotactic brain tissue identification: the NASA smart probe project.

Real-time tissue identification can benefit procedures such as stereotactic brain biopsy, functional neurosurgery and brain tumor excision. Optical scattering spectroscopy has been shown to be effective at discriminating cancer from noncancerous conditions in the colon, bladder and breast. The NASA Smart Probe extends the concept of 'optical biopsy' by using neural network techniques to combine the output from 3 microsensors contained within a cannula 2. 7 mm in diameter (i.e. the diameter of a stereotactic brain biopsy needle). Experimental data from 5 rats show the clear differentiation between tissues such as brain, nerve, fat, artery and muscle that can be achieved with optical scattering spectroscopy alone. These data and previous findings with other modalities such as (1) analysis of the image from a fiberoptic neuroendoscope and (2) the output from a microstrain gauge suggest the Smart Probe multiple microsensor technique shows promise for real-time tissue identification in neurosurgical procedures.

Brain↗
PubMed1998

The use of a sensitive equilibrium dialysis method for the measurement of free testosterone levels in healthy, cycling women and in human immunodeficiency virus-infected women.

Measurements of total and free testosterone levels in women have lacked precision and accuracy because of limited assay sensitivity. The paucity of normative data on total and free testosterone levels in healthy women has confounded interpretation of androgen levels in women with human immunodeficiency virus (HIV) infection and other disease states. Therefore, the objectives of this study were to develop sensitive assays for the measurement of the low total and free testosterone levels in women to define the range for these hormones during the normal menstrual cycle and assess the total and free testosterone levels in HIV-infected women. By using a larger volume of serum, increasing the incubation time, and reducing the antibody concentration, the sensitivity of the total testosterone assay was increased to 0.008 nmol/L, and that of the free testosterone assay was increased to 2 pmol/L. The mean percent free testosterone was 1.0 +/- 0.1% of the total testosterone. Serum total and free testosterone levels in the follicular and luteal phases were not significantly different, but both demonstrated a modest preovulatory increase, 3 days before the LH peak. Serum total [0.50 +/- 0.32 (14.60 +/- 9.22) vs. 1.2 +/- 0.7 nmol/L (34.3 +/- 21.0 ng/dL); P < 0.0001] and free testosterone levels (5.56 +/- 2.70 (1.58 +/- 0.80) vs. 12.8 +/- 5.5 pmol/L (3.4 +/- 1.7 pg/mL); P < 0.0001) were significantly lower in HIV-infected women (n = 37) than in healthy women (n = 34). Serum total and free testosterone levels were also significantly lower in HIV-infected women who were menstruating normally. There were no significant differences in serum total and free testosterone levels between those who had lost weight and those who had not. Testosterone levels correlated inversely with plasma HIV ribonucleic acid copy number. Serum FSH, but not LH, levels were significantly higher in HIV-infected women than in controls. Using assays with sufficient sensitivity, we defined the range for total and free testosterone levels during the normal menstrual cycle. Serum total and free testosterone levels are lower in HIV-infected women and correlate inversely with plasma HIV ribonucleic acid levels. The hypothesis that androgen deficiency contributes to wasting in HIV-infected women remains to be tested.

Adult↗
PubMed1997

Robotic multimodality stereotactic brain tissue identification: work in progress.

Real-time identification of tissue would improve procedures such as stereotactic brain biopsy (SBX), functional and implantation neurosurgery, and brain tumor excision. To standard SBX equipment has been added: (1) computer-controlled stepper motors to drive the biopsy needle/probe precisely; (2) multiple microprobes to track tissue density, detect blood vessels and changes in blood flow, and distinguish the various tissues being penetrated; (3) neural net learning programs to allow real-time comparisons of current data with a normative data bank; (4) three-dimensional graphic displays to follow the probe as it traverses brain tissue. The probe can differentiate substances such as pig brain, differing consistencies of the 'brain-like' foodstuff tofu, and gels made to simulate brain, as well as detect blood vessels imbedded in these substances. Multimodality probes should improve the safety, efficacy, and diagnostic accuracy of SBX and other neurosurgical procedures.

Animals↗
PubMed1997

Plasma levels of beta-endorphin during the menstrual cycle.

During recent years, many research teams have suggested a possible role of endogenous opiates in the control of the menstrual cycle. The level of immunoreactive beta-endorphin was measured on different days during the ovulatory cycle of 131 healthy volunteers. The levels of luteinizing hormone (LH), follicle-stimulating hormone (FSH), 17 beta-estradiol and progesterone were also measured. The graphic representation of opiate levels during the female menstrual cycle, where day O is the day of ovulation, shows that plasmatic beta-endorphin levels are not stable throughout. The levels increase progressively during the follicular phase, reaching a maximum (mean 139.49 pg/ml, SD 42.23 pg/ml, 95% confidence interval 121.22-157.75 pg/ml) 4 days before ovulation. During the periovulatory period (days-3 to +3) levels of beta-endorphin are very stable (mean day 0, 27.8 pg/ml, SD 6.36 pg/ml, 95% confidence interval 19.29-27.83 pg/ml) and low (p < 0.05), followed by a renewed increase during the luteal phase (mean day + 5, 87.86 pg/ml, SD 36.49 pg/ml) where a maximum level (mean 102.78 pg/ml, SD 30.35 pg/ml) is reached 24 h before the next menses. The beta-endorphin level has a negative correlation with the LH level (r = -0.50, p < 0.001) on the preovulatory days, and during the luteal phase a positive linear correlation (r = 0.47, p < 0.001) is found with the progesterone level. It seems that beta-endorphin levels in the plasma are influenced by the ovarian steroids. However, the influence of the plasmatic opiate on the gonadotropins is currently under discussion.

Adolescent↗
PubMed1996

Surgical correction of velopharyngeal insufficiency with and without compensatory articulation.

The final speech outcome in cleft palate patients depends on two elements: normalization of nasal resonance and correction of compensatory articulation (CA). The purpose of this paper is to demonstrate whether early surgical correction of velopharyngeal insufficiency (VPI) may decrease total time of speech therapy (ST) necessary to completely eliminate CA. A group of 29 cleft palate patients in which VPI and CA were demonstrated, were selected for the study group. Fourteen patients were randomly selected and underwent surgical correction of VPI as soon as placement of articulation during isolated speech was normal. The other 15 patients underwent speech therapy aimed to correct CA, these patients were followed until articulation was normal during connected speech. At this point in time they underwent surgical correction of VPI as the other 14 patients. Success rate for correcting VPI after the operation was not significantly different for both groups. Furthermore, total time of ST was not significantly different for both groups. It is concluded that normalization of nasal resonance before articulation is corrected during connected speech does not seem to reduce total time of ST necessary to completely correct CA in cleft palate patients.

Adolescent↗