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Biomedical subjects

M Lorente

Publications and source records attributed to M Lorente.

At least 19 recordsLinked to original sources
PubMed2002

[HIV prevalence among homosexual and bisexual men in Spain, 1992-2000].

BACKGROUND: Our purpose was to describe the time trend in HIV seroprevalence among homo/ bisexual men. SUBJECTS AND METHOD: We analyzed 9,383 homo/ bisexual men who had a first voluntary test for HIV in 10 Spanish clinics from 1992 to 2000. RESULTS: HIV prevalence decreased from 20.3% in 1992 to 8.4% in 2000. In the multivariate analysis this decline appeared independently associated with the testing year and the birth cohort. CONCLUSIONS: New generations of voluntarily tested homo/bisexual men are less infected by HIV, but it is yet necessary to intensify the prevention programs.

Adolescent↗
PubMed2002

Chronic hypoxia induced ultrastructural changes in the rat adrenal zona glomerulosa.

The adrenal cortex plays an important role in adaptation to various forms of stress, including hypoxia. While physiological changes in the aldosterone metabolism during hypoxia have been extensively described, few studies have focused on the morphological changes in the adrenal glands under chronic hypoxia. We studied the ultrastructure of the zona glomerulosa of 6-month-old Wistar rats exposed to chronic normobaric hypoxia. Animals were divided into two groups: control (n=12) and hypoxic (n=12). In this latter group, the animals were kept at 7% O2 concentration after a gradual adaptation (21, 15, 12, 10, 8, 7 vol% O2). The duration of the study was 112 days. In comparison with normoxic rats, body weight and adrenal gland weight of hypoxic animals was significantly reduced by 18.5% (p=0.006) and 14.7% (p=0.001) respectively. The thickness of the zona glomerulosa decreased due to atrophy of cells. The main ultrastructural changes observed were: 1) a decrease in, or complete elimination of, lipid droplet content; 2) a marked increase in lysosome number; and 3) the presence of giant mitochondria. Our findings show that rats fail to adapt to severe chronic hypoxia. The ultrastructural changes in the zona glomerulosa found in the present study could reflect changes in the aldosterone pathway.

Adrenal Glands↗
PubMed2001

Online reference database of European Y-chromosomal short tandem repeat (STR) haplotypes.

The reference database of highly informative Y-chromosomal short tandem repeat (STR) haplotypes (YHRD), available online at http://ystr.charite.de, represents the largest collection of male-specific genetic profiles currently available for European populations. By September 2000, YHRD contained 4688 9-locus (so-called "minimal") haplotypes, 40% of which have been extended further to include two additional loci. Establishment of YHRD has been facilitated by the joint efforts of 31 forensic and anthropological institutions. All contributing laboratories have agreed to standardize their Y-STR haplotyping protocols and to participate in a quality assurance exercise prior to the inclusion of any data. In view of its collaborative character, and in order to put YHRD to its intended use, viz. the support of forensic caseworkers in their routine decision-making process, the database has been made publicly available via the Internet in February 2000. Online searches for complete or partial Y-STR haplotypes from evidentiary or non-probative material can be performed on a non-commercial basis, and yield observed haplotype counts as well as extrapolated population frequency estimates. In addition, the YHRD website provides information about the quality control test, genotyping protocols, haplotype formats and informativity, population genetic analysis, literature references, and a list of contact addresses of the contributing laboratories.

Databases, Factual↗
PubMed2001

The axillopectoral muscle (of Langer): report of three cases.

The axillopectoral muscle, usually called Langer's axillary arch instead of Langer's arm arch, is a supernumerary muscle and is the principal anatomic variation of the axilla. Three cases of the muscle were observed originating from latissimus dorsi crossing over the axillary neurovascular bundle and inserting deep to the insertion of pectoralis major or into the coracoid process. Clinicians should be aware of its existence as it can give rise to different pathologies. It should be recognised and excised to expose the axillary artery and vein in patients with trauma and to perform axillary lymphadenectomy or axillary bypass. It should be considered in the differential diagnosis of axillary masses or in a history of intermittent axillary vein obstruction. If the muscle causes problems its excision should be curative.

Aged↗
PubMed2001

Identification of missing persons: the Spanish "Phoenix" program.

In 1999, Spain was the first country to officially start a National Program to try to identify cadavers and human remains which could not be identified by the use of traditional forensic approaches. This attempt is called "Phoenix Program". Two independent mitochondrial DNA (mtDNA) databases were generated, which can automatically compare and match identical or similar sequences. One is the Reference Database, with mtDNA sequences from maternal relatives of missing persons, who provide the samples (buccal swabs) voluntarily; the other is the Questioned Database, comprised of mtDNA data of unknown remains and cadavers. Although the first phase of the program (typing of all unidentified human remains) will probably not be completed until December 2003, positive identifications are being made in the interim. To date, more than 1,200 families have contacted Phoenix, and at least 280 reference samples and 48 questioned evidences have been analyzed. When mtDNA matches are found, another independent analysis is performed as a part of the quality control mechanism. Once a match is confirmed (so far in 6 cases), an attempt is made to analyze short tandem repeat (STR) loci. We call for international collaboration to make this effort valuable worldwide.

Cadaver↗
PubMed1999

Spanish population data on the loci D13S317, D7S820, and D16S539 generated using silver staining (SilverSTR III Multiplex).

A set of 212 samples from unrelated Spanish Caucasians living in Andalucia (southern Spain) were analyzed with a new commercially-available kit for multiplex amplification of 3 STR loci (D13S137, D7S820, and D16S539), manual denaturing polyacrylamide gel electrophoresis and silver staining. These three loci are of special interest for the forensic community since they are a part of the 13 CODIS-core STR loci. The results show that the loci D13S317 and D16S539 meet Hardy-Weinberg expectations (HWE), but the locus D7S820 did not meet HWE (p = 0.003). However, there was no detectable departures from independence (i.e., linkage disequilibrium) between any pair-wise combination of loci. The D7S820 data were further investigated. The excess homozygosity was due to an excess of D7S820 10, 10 homozygotes. To determine if the allele frequency data are meaningful and can be applied to forensic identity cases, the Spanish D7S820 allele frequency data were compared with four other Caucasian sample populations. The D7S820 allele frequencies were statistically similar; thus, the results support that the allele frequency data can be used reliably for estimating DNA profile frequencies.

Alleles↗
PubMed1998

Fluorescent multiplex analysis of nine STR loci: Spanish population data.

A total of 171 Caucasians living in Andalucia (southern Spain) have been typed for nine short tandem repeat (STR) loci by multiplex PCR amplification using a commercially available kit (Profiler Plus; Perkin-Elmer, Norwalk, CT, USA) and semi-automatic electrophoresis (ABI Prism 377 DNA Sequencer, Applied Biosystems, Foster City, CA, USA). The kit enables typing of the STR loci D3S1358, VWA, FGA, D5S818, D13S317, D7S820, D8S1179, D21S11, and D18S51. All loci, except D7S820, meet Hardy-Weinberg equilibrium. Because of the large number of loci that can be analyzed, the power of discrimination (PD) is greater than 0.99999, and the probability of exclusion (PE) reaches 0.99991 in our population sample.

Alleles↗
PubMed1998

Dandruff as a potential source of DNA in forensic casework.

Dandruff is a clinical alteration of the skin that consists histologically of orthokeratotic clumps with minute parakeratotic foci found in inflammatory pathologies such as seborrheic dermatitis and psoriasis. Therefore, some nucleated cells should be found in dandruff and hence there is a possibility that forensically typeable DNA could be extracted from dandruff. Because of a particular case in which we were involved, a study was carried out to determine whether or not DNA could be extracted from dandruff, and if the two most widely used extraction techniques (Chelex and organic) would be applicable. Results show that sufficient quantities of DNA (more than 30 to 40 ng) can be obtained from as little as 1.0 to 1.5 mg of dandruff. Both methods yield DNA, although the organic procedure seems to yield more (72.5 ng Chelex vs. 183.3 ng organic). All the DNA samples extracted were typed correctly for the loci HUMTH01 and HUMvWA. Therefore, dandruff can be considered a potential source of DNA for forensic identification.

Clothing↗
PubMed1997

Spanish population data on seven loci: D1S80, D17S5, HUMTH01, HUMVWA, ACTBP2, D21S11 and HLA-DQA1.

Blood samples from 120 Spanish Caucasian individuals were amplified and typed by electrophoresis at six loci, and by reverse dot-blot hybridization at one locus. Results demonstrate the assumption of independence within and between the seven loci analyzed. Therefore, a Spanish population database has been established and statistical analysis shows that a high degree of discrimination can be obtained when all seven (or fewer) loci are used to characterize forensic biological evidence.

DNA↗
PubMed1997

Indisputable double paternity in dizygous twins.

OBJECTIVE: To report a case of heteropaternal superfecundation. DESIGN: Case report. SETTING: University paternity laboratory. PATIENT(S): Father, mother, and a set of twins. INTERVENTION(S): Blood typing conventional markers, as well as polymerase chain reaction loci and restriction fragment length polymorphism loci of DNA. MAIN OUTCOME MEASURE(S): Heteropaternal superfecundation was demonstrated after paternity investigation. RESULT(S): The probability of paternity for twin 1 was 99.9999998%, whereas that for twin 2 was excluded on the basis of the following tests: Fy, Pi, human leukocyte antigen (HLA)-DQA1, D1S80, D17S5, HBGG, D5S110, D2S44, and D10S28. CONCLUSION(S): Dizygous twins can have different biologic fathers, as demonstrated in this case. According to published data, the frequency of twins with different fathers is probably underestimated, at least in small selected populations such as those of paternity suits.

Blood Grouping and Crossmatching↗
PubMed1997

An improved method to recover saliva from human skin: the double swab technique.

Human bite mark evidence is often found in violent crimes. Due to the difficulties of physically comparing an injury site on elastic and curved skin surfaces to the teeth of a suspect, the authors have considered using salivary DNA evidence to identify the bite perpetrator. Several techniques were evaluated to determine the best method of recovering saliva from human skin before extracting genomic DNA from the collection substrate. A classical stain recovery technique using a wet cotton swab was tested against one utilizing a wet filter paper. Additionally, a new method, referred to as the double swab technique, using a wet cotton swab followed by a dry cotton swab was also evaluated. After recovering a dried saliva stain, DNA was extracted using the modified Chelex method, quantified using the slot-blot procedure, and amplified at three polymorphic loci. The double swab technique showed the highest percentage recovery of saliva from human skin among the three methods studied. This technique is suggested as an improvement over the classical single wet cotton swab technique.

Bites and Stings↗
PubMed1997

PCR-based DNA typing of saliva stains recovered from human skin.

Human bites in cases of homicide, sexual assault, and abuse are often distorted due to the elasticity and curvature of the skin. Physical comparison of a bite mark to a suspect's teeth is sometimes difficult. Saliva, which is usually deposited during biting, can be collected and analyzed to identify the perpetrator. Using simulated bite mark situations in two experimental series, three samples of 40 microL of whole saliva were deposited on the skin of 27 cadavers (at 33 sites) and three samples of 100 microL of whole saliva were deposited on the skin of 5 cadavers (at 12 sites). Saliva was collected using the double swab technique at t = 5 min, t = 24 h, and t = 48 h. DNA was extracted using the modified Chelex method and submitted to PCR-based typing at two short tandem repeat loci. Results indicate that the concentration of DNA in saliva recovered from skin varies as a function of time since deposition. There is a significant decrease in concentration in the first 24 h but the concentration remains stable from 24 to 48 h. The success of PCR amplification is independent of the time since deposition or the concentration of DNA in the saliva sample. Contamination from the DNA of the cadaver was not found in any of the cases studied.

Bites, Human↗
PubMed1997

Sequential multiplex amplification: utility in forensic casework with minimal amounts of DNA and partially degraded samples.

Since its introduction, PCR has become a widely-used, routine technique in forensic laboratories. A number of PCR protocols that were developed originally are now being replaced by more powerful approaches, particularly those based on multiplex amplification of short tandem repeat (STR) loci. One alternative from of multiplex PCR amplification, called Sequential Multiplex Amplification (SMA), was designed to amplify a single locus and then recover and reuse the remaining genomic DNA as a template for subsequent PCR. The SMA process could be repeated several times. SMA has proven to be useful in typing genomic DNA contained in stored PCR samples and analyzing samples of limited quality and/or quantity for multiple loci. The efficacy of the use of SMA for actual typing of casework samples permitted typing for a second locus 98.11% of the samples considered; 70.75% were typeable for a third locus, and 16.98% for a fourth locus.

Blood Stains↗
PubMed1996

Increasing DNA extraction yield from saliva stains with a modified Chelex method.

Recovery, preservation and analysis of body fluid stains is an important aspect of forensic science. PCR-based typing of DNA extracted from recovered stains is often a crucial method to identify a perpetrator or exclude an innocent suspect. This paper reports an improved method of extracting genomic DNA from saliva stains deposited on human skin in simulated bite mark situations. Results of organic (phenol-chloroform) extraction and Chelex extraction were compared to a modified Chelex method developed by the authors. Modifications include pre-extraction preparation with proteinase K and incubations at 56 degrees C and 100 degrees C plus microconcentration of the solution. Quantification results using the classical Chelex extraction method showed that 31.9 +/- 4.22% of the deposited DNA was recovered, but using the modified Chelex extraction method DNA recovery was increased to 47.7 +/- 6.90%. The quantity and quality of extracted DNA was shown to be adequate for PCR-based typing at two STR loci.

Bites and Stings↗