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Biomedical subjects

V Mann

Publications and source records attributed to V Mann.

At least 19 recordsLinked to original sources
PubMed2001

[Changes in the cytokine network through escalating SIRS after heart surgery].

Changes in the Cytokine Network Through Escalating SIRS After Heart Surgery. Cardiopulmonary bypass is associated with an injury that may cause pathophysiological changes in form of systemic inflammatory response syndrome (SIRS) or multiple organ dysfunction syndrome (MODS). There is a lot of information about the immunologic alterations in patients undergoing cardiopulmonary bypass, but only little is known about the expression of cytokines in patients with severe SIRS or MODS following cardiovascular surgery. In the present study, we investigated the inflammatory response of patients with an escalating SIRS following open heart surgery. Plasma levels of cytokines (IL-1beta, IL-6, IL-8, IL-10, IL-12, IL-18, GM-CSF and TGF-beta) were measured at the first four postoperative days in 12 adult male patients with severe SIRS (SIRS-group), and 15 patients with uncomplicated course (control-group) following myocardial revascularization. All cytokines (except IL-1beta) were significantly elevated in SIRS-patients, the analysis of differences between the survivors and non-survivors within the SIRS-group showed dramatically elevated levels of IL-8 and IL-18 in non-survivors. From the results of our investigation we can conclude that monitoring of immunologic parameters, e.g. IL-8 and/or IL-18 may be helpful for the early detection and prognosis of high-risk patients with severe SIRS and MODS following cardiac surgery.

Aged↗
PubMed2001

A COL1A1 Sp1 binding site polymorphism predisposes to osteoporotic fracture by affecting bone density and quality.

Osteoporosis is a common disease with a strong genetic component. We previously described a polymorphic Sp1 binding site in the COL1A1 gene that has been associated with osteoporosis in several populations. Here we explore the molecular mechanisms underlying this association. A meta-analysis showed significant associations between COL1A1 "s" alleles and bone mineral density (BMD), body mass index (BMI), and osteoporotic fractures. The association with fracture was stronger than expected on the basis of the observed differences in BMD and BMI, suggesting an additional effect on bone strength. Gel shift assays showed increased binding affinity of the "s" allele for Sp1 protein, and primary RNA transcripts derived from the "s" allele were approximately three times more abundant than "S" allele--derived transcripts in "Ss" heterozygotes. Collagen produced from osteoblasts cultured from "Ss" heterozygotes had an increased ratio of alpha 1(I) protein relative to alpha 2(I), and this was accompanied by an increased ratio of COL1A1 mRNA relative to COL1A2. Finally, the yield strength of bone derived from "Ss" individuals was reduced when compared with bone derived from "SS" subjects. We conclude that the COL1A1 Sp1 polymorphism is a functional genetic variant that predisposes to osteoporosis by complex mechanisms involving changes in bone mass and bone quality.

Aged↗
PubMed2000

Metabolic engineering of astaxanthin production in tobacco flowers.

Using metabolic engineering, we have modified the carotenoid biosynthesis pathway in tobacco (Nicotiana tabacum) to produce astaxanthin, a red pigment of considerable economic value. To alter the carotenoid pathway in chromoplasts of higher plants, the cDNA of the gene CrtO from the alga Haematococcus pluvialis, encoding beta-carotene ketolase, was transferred to tobacco under the regulation of the tomato Pds (phytoene desaturase) promoter. The transit peptide of PDS from tomato was used to target the CRTO polypeptide to the plastids. Chromoplasts in the nectary tissue of transgenic plants accumulated (3S,3'S) astaxanthin and other ketocarotenoids, changing the color of the nectary from yellow to red. This accomplishment demonstrates that plants can be used as a source of novel carotenoid pigments such as astaxanthin. The procedures described in this work can serve as a platform technology for future genetic manipulations of pigmentation of fruits and flowers of horticultural and floricultural importance.

Bacterial Proteins↗
PubMed2000

Recombinant chimeric proteins generated from conserved regions of Plasmodium falciparum merozoite surface protein 2 generate antiparasite humoral responses in mice.

The merozoite surface protein 2 of P. falciparum is highly polymorphic in nature, but has regions of almost complete conservation at its N- and C-termini. We produced a chimeric recombinant protein comprising these regions only (hereafter termed NC). Mice immunized with the NC antigen produce antibodies at levels comparable to those immunized with 1624, a full-length recombinant protein representing MSP2 from P. falciparum. Antisera raised against NC recognized P. falciparum schizonts by IFA and a P. falciparum protein of Mr 45 kDa by Western blot. However, antibody specificities were observed to differ between anti-NC and anti-1624 sera, and this resulted in differences in parasite recognition, despite similar levels of antibodies having been produced. The response to the NC antigen was also shown to be restricted in some mice (H2-d), but this was overcome by including appropriate T-cell help, which was accomplished by creating recombinant protein chimeras that contained NC and T-helper epitopes from Tetanus toxoid, or MSP119 from P. berghei.

Adolescent↗
PubMed2000

Laparoscopic subtotal cholecystectomy: a review of 56 procedures.

BACKGROUND AND PURPOSE: The essential surgical steps in laparoscopic cholecystectomy remain similar to those of open cholecystectomy. Positive identification of the biliary anatomy, safe clipping or ligature of the cystic duct and artery, and dissection of the gallbladder from the liver bed form the basis of cholecystectomy. Subtotal cholecystectomy is a definitive and safe operation under certain adverse conditions intraoperatively for dissection of the gallbladder from the liver bed. We reviewed our experience with laparoscopic cholecystectomy over a 2-year period between June 1996 and May 1998, when 1,680 operations were performed. The objective was to analyze the pathology, review surgical procedures, and trace the outcome of laparoscopic subtotal cholecystectomy. PATIENTS AND METHODS: In 56 of 1,680 patients, laparoscopic subtotal cholecystectomy was performed, which constituted 3.33% of the laparoscopic cholecystectomies performed at our institution. Dense fibrosis and adhesions were present in 32 patients; 12 patients had Mirizzi syndrome, 6 patients had a sessile gallbladder, and 6 patients had a gangrenous gallbladder. The Endo-GIA 30 stapler was used in 40 patients, sequential clips were used in 9 patients, and a suture for stump closure was used in 5 patients. A subhepatic drain was inserted in 50 patients. RESULTS: Two conversions to open surgery were needed because of gangrene of the gall bladder wall and one conversion as a result of continued bleeding from the cystic artery after application of the Endo-GIA 30 stapler. The mean postoperative stay in hospital was 2.5 days. One patient had a solitary bile duct calculus extracted at endoscopic retrograde cholangiopancreatography 3 months after surgery. Three patients had biliary drainage that lasted for a week, and four patients had epigastric port-site infections that resolved with antibiotics, dressings and postural drainage. CONCLUSION: Laparoscopic subtotal cholecystectomy is safe, feasible, and effective and may help prevent conversion to open surgery in carefully selected patients with difficult cholecystectomies.

Cholecystectomy, Laparoscopic↗
PubMed2000

Laparoscopic ventral hernia repair.

PURPOSE: A retrospective study was carried out of patients who underwent laparoscopic ventral abdominal wall hernia repair (excluding groin hernias) between January 1994 and January 1999. PATIENTS AND METHODS: Laparoscopic ventral hernia repair was performed on 202 patients for defects ranging from 1.5 cm to 12 cm in diameter. Of these, 35 patients had multiple hernial defects. After reduction of the hernial contents and adhesiolysis, a polypropylene mesh was used intraperitoneally in all patients, such that there was a margin of at least 3 cm from the edge of the defect as well as the previous scar. RESULTS: The mean operating time decreased from 90 minutes in the initial 3 years to 50 minutes in the last 2 years. Postoperatively, the mean hospital stay was 1.8 days. Patients complained of somatic abdominal pain at the site of mesh insertion for a mean of 7 days. There were two postoperative hernia recurrences at a mean follow-up of 2.9 years. The incidence of seroma formation postoperatively was 32% in the first 3 years but declined to 18% subsequently with postoperative abdominal-wall pressure dressings. There were no postoperative sequelae related to bowel adhesions. Negligible wound sepsis (superficial wound infection in five patients), decreased morbidity, and all the other advantages of a minimally invasive surgical approach were evident in this group of patients. CONCLUSION: These promising early results need to be confirmed by a prospective controlled trial, especially recurrence rates and incidence of postoperative adhesions.

Adult↗
PubMed2000

The management of Mirizzi syndrome in the laparoscopic era.

Mirizzi syndrome is a rare complication of long-standing gallstone disease resulting in obstructive jaundice. Careful perioperative management is of utmost importance because of an increased risk of bile duct injury intraoperatively. Experience with Mirizzi syndrome over a period of 3 years, from January 1996 to December 1998, was reviewed. Twenty-seven patients were operated upon, which constituted 0.9% of 2840 patients who underwent laparoscopic cholecystectomy in the authors' department. There were 12 patients with Mirizzi type I syndrome and 15 patients with Mirizzi type II syndrome, according to McSherry classification. Six (22%) conversions were reported, all because of unclear anatomy and inherent limitations of the laparoscopic approach. For the remaining 21 (78%) patients, the procedure was completed laparoscopically. No bilioenteric anastomosis was required. A preoperative stent insertion in the common bile duct (CBD) during endoscopic retrograde cholangiopancreatography (ERCP) enabled us to achieve primary closure of CBD in every case. There was no perioperative mortality, and patients remained well for an average 2.1-year follow-up. It is highly desirable to have a preoperative diagnosis of Mirizzi syndrome, and the laparoscopic approach is not a contraindication in specialized centers. Our current management protocol to treat Mirizzi syndrome consists of a high degree of suspicion at ERCP, with stenting preoperatively and a complete stone clearance with subtotal cholecystectomy intraoperatively.

Cholangiopancreatography, Endoscopic Retrograde↗
PubMed1999

Complete penoscrotal transposition and associated malformations.

Complete transposition of the penis and scrotum, or prepenile scrotum, is an uncommon congenital malformation. Concomitant genitourinary abnormalities, often life-threatening in nature, are frequently seen, and major malformations involving other organ systems may also be present. We report a newborn in whom complete penoscrotal transposition was accompanied by urethral atresia and radial dysgenesis.

Abnormalities, Multiple↗
PubMed1999

Plasma levels of selectins and interleukins in cardiovascular surgery using cardiopulmonary bypass.

BACKGROUND: Cardiovascular surgery with cardiopulmonary bypass (CPB) leads to activation of a variety of inflammatory pathways, including the release of cytokines and selectins. METHODS: In 20 patients undergoing elective coronary artery bypass grafting, plasma levels of interleukins IL-2, -6, -8, -10, -12 and of P-, E-, and L-selectins were measured at eight time points before, during, and after CPB using a standardized ELISA technique. RESULTS: IL-2 plasma levels decreased significantly after the start of CPB and remained low until the second postoperative day. IL-6 and IL-8 levels increased significantly after weaning off CPB, with mean peak values six hours postoperatively. Very low IL-10 plasma levels were detectable preoperatively. They remained low during CPB and peaked significantly after weaning off CPB until skin closure. The IL-12 levels decreased after weaning off CPB (p < 0.05) until 6 hours postoperatively. The plasma levels of P-selectin showed no alterations, but concentrations of E- and L-selectin decreased after the start of CPB (p < 0.05). There were no adverse postoperative events. CONCLUSIONS: The results of our study demonstrate a dysregulation of cytokine and selectin production during and up to 48 h after CPB, which may be a "normal" stress reaction to CPB.

Adult↗
PubMed1999

Endoscopic neck surgery: expanding horizons.

There have now been several attempts at neck exploration using minimally invasive surgery. These encouraging reports paved the way for the authors to attempt endoscopic neck surgery. Having the necessary technical expertise in minimally invasive surgery with an experience of more than 6000 laparoscopic procedures, they attempted endoscopic parathyroidectomy in three patients with hyperparathyroidism. Of these, two had a hyperfunctioning adenoma and one had parathyroid hyperplasia. The hyperfunctioning tissue was accurately localized using a 99Tc-thallium subtraction scan. It was possible to localize and dissect the parathyroid tissue in two of the three patients. One patient required an open hemithyroidectomy before the adenoma could be localized and excised. The total operative time averaged 113 min. The working space was found to be adequate provided good hemostasis was maintained. The magnification proved excellent in identifying and defining important neck structures. Sufficient mobilization of the lateral thyroid lobe for access to the tracheoesophageal groove was found to be technically very difficult. No subcutaneous emphysema was observed beyond the neck region, and none lasted beyond 24 h. Cosmesis was acceptable to both the patient and the surgeon.

Adenoma↗
PubMed1996

Lexical familiarity and English-language experience affect Japanese adults' perception of / / and /l/.

This study assessed the influence of subjective lexical familiarity and English-language experience on Japanese adults' accuracy in identifying singleton word-initial tokens of English [symbol: see text] and /l/. The inexperienced Japanese (IJ) subjects had lived in the U.S. for 2 years, whereas the experienced Japanese (EJ) subjects had lived there for 21 years, on average. The native Japanese subjects correctly identified English [symbol: see text] and /l/ tokens less often than did a group of native English (NE) subjects, but they did not differ from the NE subjects in identifying the control consonants /w/ and /d/. The NE subjects, who were at ceiling, showed no effect of subjective lexical familiarity. However, the EJ and IJ subjects correctly identified [symbol: see text] and /l/ tokens more often in words that were more familiar than their minimal pairs than in words that were less familiar than their minimal pairs. The EJ subjects identified liquids more often than did the IJ subjects, but usually less often than the NE subjects. However, the EJ subjects managed to identify [symbol: see text] tokens at rates comparable to the NE subjects' rates in words that wer matched in subjective familiarity to their minimal pair (experiment 1), and when identifying [symbol: see text] tokens that had been edited out of their original word or nonword context (experiment 2).

Humans↗
PubMed1994

Cloning and characterization of the gene for phytoene desaturase (Pds) from tomato (Lycopersicon esculentum).

The gene Pds encodes phytoene desaturase, a key enzyme in carotenoid biosynthesis that converts phytoene to zeta-carotene. We have cloned and analyzed the genomic DNA sequence of Pds from tomato. In tomato Pds is comprised of 15 exons that, together with the introns occupy over 8 kb. A putative promoter sequence has been identified by comparison with the cDNA sequence of Pds. A consensus nucleotide sequence around intron splicing sites in tomato genes was determined by compiling data on 137 introns in 34 genes. This consensus sequence generally agrees with the consensus sequence of other higher plants with only minor differences that are unique to tomato.

Amino Acid Sequence↗
PubMed1994

Use of vocalic cues to consonant voicing and native language background: the influence of experimental design.

For native speakers of English and several other languages, preceding vocalic duration and F1 offset frequency are two of the cues that convey the stop consonant voicing distinction in word-final position. For speakers learning English as a second language, there are indications that use of vocalic duration, but not F1 offset frequency, may be hindered by a lack of experience with phonemic (i.e., lexical) vowel length (the "phonemic vowel length account": Crowther & Mann, 1992). In this study, native speakers of Arabic, a language that includes a phonemic vowel length distinction, were tested for their use of vocalic duration and F1 offset in production and perception of the English consonant-vowel-consonant forms pod and pot. The phonemic vowel length hypothesis predicts that Arabic speakers should use vocalic duration extensively in production and perception. On the contrary, Experiment 1 revealed that, consistent with Flege and Port's (1981) findings, they produced only slightly (but significantly) longer vocalic segments in their pod tokens. It further indicated that their productions showed a significant variation in F1 offset as a function of final stop voicing. Perceptual sensitivity to vocalic duration and F1 offset as voicing cues was tested in two experiments. In Experiment 2, we employed a factorial combination of these two cues and a finely spaced vocalic duration continuum. Arabic speakers did not appear to be very sensitive to vocalic duration, but they were about as sensitive as native English speakers to F1 offset frequency. In Experiment 3, we employed a one-dimensional continuum of more widely spaced stimuli that varied only vocalic duration. Arabic speakers showed native-English-like sensitivity to vocalic duration. An explanation based on the perceptual anchor theory of context coding (Braida et al., 1984; Macmillan, 1987; Macmillan, Braida, & Goldberg, 1987) and phoneme perception theory (Schouten & Van Hessen, 1992) is offered to reconcile the apparently contradictory perceptual findings. The explanation does not attribute native-English-like voicing perception to the Arabic subjects. The findings in this study call for a modification of the phonemic vowel length hypothesis.

Adolescent↗
PubMed1992

Native language factors affecting use of vocalic cues to final consonant voicing in English.

Preceding vocalic information can cue final consonant voicing for native English speakers. This study examines subjects' use of two vocalic cues, vocalic duration, and F1 offset frequency, as a function of two native language factors, experience with final stop consonants, and experience with phonemic vowel length. Native speakers of English are compared to native speakers of Japanese and Mandarin Chinese who are learning English as a second language. Experiment 1 measured the F1 offset frequency and vocalic duration in productions of "pod" and "pot." Experiment 2 assessed identification of natural tokens of "pod" and "pot" with and without closure segments and bursts. Experiment 3 assessed categorization of synthetic "pod"-"pot" stimuli that systematically manipulated vocalic duration and F1 offset frequency. Native speakers of English showed the strongest implementation of and sensitivity to vocalic duration, Mandarin speakers showed significantly weaker effects, and Japanese speakers fell in between. Group-related differences in use of F1 offset frequency were smaller, and much clearer in the case of production than perception. It is hypothesized that a lack of experience with final consonants penalizes use of vocalic cues among the Japanese and Mandarin subjects, in general. The advantage of the Japanese subjects for use of vocalic duration further suggests a facilitation effect of experience with phonemic vowel length.

Adolescent↗
PubMed1991

PCR-detected genital papillomavirus infection: prevalence and association with risk factors for cervical cancer.

In an investigation conducted in student health clinic patients, the polymerase chain reaction was used to detect human papillomavirus (HPV) DNA, thereby allowing measurement of the prevalence of HPV infection and study of the association between HPV infection and risk factors for cervical cancer. Of 159 women eligible to participate, 105 (66%) provided a specimen of cervical cells for HPV typing, and also answered an interviewer-administered questionnaire which sought information on risk factors for cervical cancer. Nucleic acid extracted from cervical cells was screened with primers for HPV types 6, 11, 16, 18, 33 and with an HPV Consensus primer. Overall, the prevalence of HPV infection was 18.1%, while for HPV-6/11 it was 2.9% and for HPV-16/18 it was 10.5%. There were statistically significant increases in risk of HPV infection with a history of ever having smoked cigarettes (overall, and for HPV-16 alone) and with a history of usually having sexual intercourse during menstrual periods (overall, but not for HPV-16), and these associations were independent of the effects of age at first sexual intercourse and number of sexual partners. The latter 2 variables, as well as the total number of occasions of sexual intercourse, a history of anal intercourse, and a history of ever having used oral contraceptives, were not associated with statistically significant alterations in risk of HPV infection.

Adult↗
PubMed1991

Herpes simplex virus type 2: a possible interaction with human papillomavirus types 16/18 in the development of invasive cervical cancer.

A case-control study of 766 histologically confirmed incident cases of invasive cervical cancer and 1,532 hospital and community controls was conducted in Latin America to evaluate the etiologic role of herpes simplex virus type 2 (HSV-2) and to examine whether HSV-2 interacts with other risk factors. In addition to a personal interview, all subjects were asked to donate blood samples and cervical swabs for assessment of exposure to HSV-2 and human papillomaviruses (HPVs) respectively. Ninety-eight percent of cases and 91% of controls agreed to the interview and blood collection. Women testing positive for HSV-2 antibodies were found to have a 60% increased risk of cervical cancer compared with seronegative women (95% CI = 1.3, 1.9). Control for education, sexual and reproductive behavior, prior Pap-smear screening, smoking, oral contraceptive use, HPV-6/11 DNA, or HPV-16/18 DNA detection did not materially affect this estimate. No effect modification of HSV-2 by age, HPV-6/11 DNA, pregnancies, oral contraceptive use or cigarette smoking was observed. However, a significant interaction was detected between HSV-2 and HPV-16/18. Compared with women testing negative to both virus types, those positive for HSV-2 alone had a RR of 1.2 (95% CI = 0.9, 1.6), those positive for HPV-16/18 DNA alone had a RR of 4.3 (95% CI = 3.0, 6.0), and those positive for both viruses had a RR of 8.8 (95% CI = 5.9, 13.0). These findings corroborate recent laboratory evidence of a possible biological interaction between HSV-2 and HPV-16/18 in the development of cervical cancer. Further confirmatory studies are needed, given concerns with potential misclassification of exposure by the laboratory assays utilized.

Adult↗
PubMed1991

Human papillomavirus types 16 and 33, herpes simplex virus type 2 and other risk factors for cervical cancer in Sichuan Province, China.

Cancer of the cervix is relatively common in China, but has been investigated epidemiologically in only a few studies. In the hospital-based case-control study reported here, we investigated the role of various lifestyle and dietary factors, as well as infection with human papillomavirus (HPV) types 16 and 33 and herpes simplex virus type 2 in the aetiology of invasive cervical cancer. The study was conducted in Sichuan province, and involved 101 cases with histologically-confirmed cervical cancer recruited from the gynaecological oncology clinic of the West China University Hospital, and 146 controls recruited from patients attending the gynaecology clinic of the same hospital. Risk of cervical cancer was greatly increased in association with infection with HPV 16/33, the adjusted odds ratio for those with evidence of infection being 32.9 (95% CI 7.7-141.1). In contrast, infection with HSV 2 was not associated with a significantly altered risk of cervical cancer. Indices of sexual history and of dietary habits also showed no association with risk of cervical cancer, while good personal and genital hygiene were associated with markedly reduced risk. Although the results of this study are consistent with a causal role for HPV in the aetiology of cervical cancer, bias or increased viral expression following malignant transformation cannot be excluded as explanations for the strong positive association.

Case-Control Studies↗