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Biomedical subjects

S R Lewis

Publications and source records attributed to S R Lewis.

At least 19 recordsLinked to original sources
PubMed2000

Effect of menstrual cycle on HIV-1 levels in the peripheral blood and genital tract. WHS 001 Study Team.

OBJECTIVE: To assess the variation in HIV-1 over the menstrual cycle, including RNA levels in the female genital tract, plasma HIV-1-RNA levels, CD4 cell counts, and culturable virus. DESIGN: A prospective analysis of 55 HIV-1-infected women. METHODS: Blood and genital tract specimens were collected weekly over 8 weeks, spanning two complete menstrual cycles. Applying repeated-measures models that used menses as the reference level, the variation in viral RNA levels was compared in endocervical canal fluid and cells (collected by Sno-strips and cytobrush, respectively) and ectocervicovaginal lavage (CVL) fluid. Repeated-measures models were also used to assess the variation in plasma CD4 cell counts and viral load. RESULTS: Shedding patterns differed among the three sampling methods, independent of genital tract co-infections. Genital tract HIV-1-RNA levels from CVL fluid and endocervical canal cytobrush specimens were highest during menses and lowest immediately thereafter (P = 0.001 and P = 0.04). The HIV-1-RNA level in endocervical canal fluid was highest in the week preceding menses (P = 0.003). The menstrual cycle had no effect on blood levels of RNA (P = 0.62), culturable virus (P = 0.34), or CD4 cell counts (P = 0.55). HIV-1-RNA levels were higher in endocervical canal fluid than in peripheral blood plasma during the late luteal phase (P = 0.03). CONCLUSION: HIV-1-RNA levels vary with the menstrual cycle in the female genital tract but not the blood compartment. HIV-1-RNA levels are higher in endocervical canal fluid than in blood plasma. These findings may have important implications for sex-specific pathogenesis, heterosexual transmission, and contraceptive hormone interventions in HIV-1-infected women.

Adult↗
PubMed1999

Cigarettes, alcohol, marijuana, other risk behaviors, and American youth.

Increases in adolescent marijuana and other drug use have created widespread concern. One theory argues that increased use of cigarettes and alcohol among younger adolescents leads to greater use of marijuana which, in turn, leads to subsequent use of other drugs (e.g. cocaine, heroin, hallucinogens). Detractors of this theory claim that use of these substances is a symptom of a larger set of destructive behaviors (e.g. violence, suicide, promiscuous sex), and marijuana has no independent effect on the use of other more serious drugs. The authors examined whether, for high school seniors, early use of cigarettes, alcohol and marijuana has an independent effect on more serious drug use even when other behaviors are considered. Using the 1995 Youth Risk Behavior Survey (n = 2871) and logistic analysis, after accounting for selected other behaviors, seniors using cigarettes before age 13 were 3.3 (95% C.I. 2.3,4.6) times likelier to have used marijuana than ones who never smoked; for alcohol, the odds ratio was 4.5 (2.6,7.7). Seniors using marijuana before the age of 14 were 7.4 times (4.0,13.6) likelier to have used other drugs. Though no causal effect is demonstrated, cigarette and alcohol use was associated with the likelihood of marijuana use; marijuana use was associated with the likelihood of other drug use, even after selected other risk and protective behaviors were considered.

Adolescent↗
PubMed1999

Cloning of the mouse somatostatin receptor subtype 5 gene: promoter structure and function.

Somatostatin is a peptide hormone whose actions are mediated by five somatostatin receptor subtypes (sstl-5). In the pituitary, somatostatin inhibits TSH release from thyrotropes and GH release from somatotropes. We have shown that sst5 transcripts and protein are induced by thyroid hormone in TtT-97 thyrotropic tumors. To map sequences responsible for promoter activity in pituitary cells, we cloned the mouse sst5 coding region of 362 amino acids and 12 kb of upstream DNA. Initial transfection studies in TtT-97 or GH3 cells mapped high levels of basal promoter activity to a 5.6-kb fragment upstream of the translational start, whereas shorter genomic fragments had low activity. To identify the transcriptional start site we used 5' RACE with TtT-97 poly A+ RNA and a sst5 antisense coding region primer. Sequence comparison between the complementary DNA and the gene revealed that the mouse sst5 gene contains 3 exons and 2 introns. The entire coding region was contained in exon 3. Two differently sized RACE products demonstrated alternate exon splicing of two untranslated exons in TtT-97 cells. A promoter fragment from -290/+48 linked to a luciferase reporter demonstrated 600- and 900-fold higher activity over a promoterless control in GH3 mammosomatotropes and TtT-97 thyrotropes, respectively, whereas a larger fragment extending to -6400 exhibited no additional promoter activity. Cloning of the sst5 gene will facilitate the mapping of basal and regulated responses at the transcriptional level.

Amino Acid Sequence↗
PubMed1997

Pit-1 and GATA-2 interact and functionally cooperate to activate the thyrotropin beta-subunit promoter.

The molecular determinants governing cell-specific expression of the thyrotropin (TSH) beta-subunit gene in pituitary thyrotropes are not well understood. The P1 region of the mouse TSHbeta promoter (-133 to -88) region interacts with Pit-1 and an additional 50-kDa factor at an adjacent site that resembles a consensus GATA binding site. Northern and Western blot assays demonstrated the presence of GATA-2 transcripts and protein in TtT-97 thyrotropic tumors. In electrophoretic mobility shift assays, a comigrating complex was observed with both TtT-97 nuclear extracts and GATA-2 expressed in COS cells. The complex demonstrated binding specificity to the P1 region DNA probe and could be disrupted by a GATA-2 antibody. When both Pit-1 and GATA-2 were combined, a slower migrating complex, indicative of a ternary protein-DNA interaction was observed. Cotransfection of both Pit-1 and GATA-2 into CV-1 cells synergistically stimulated mouse TSHbeta promoter activity 8.5-fold, while each factor alone had a minimal effect. Mutations that abrogated this functional stimulatory effect mapped to the P1 region. Finally, we show that GATA-2 directly interacts with Pit-1 in solution. In summary, these data demonstrate functional synergy and physical interaction between homeobox and zinc finger factors and provide insights into the transcriptional mechanisms of thyrotrope-specific gene expression.

Animals↗
PubMed1988

Reconstruction of the burned palm: full-thickness versus split-thickness skin grafts--long-term follow-up.

The long-term results of full-thickness (N = 11) and split-thickness (N = 14) skin grafts for reconstitution of the palmar surface following release of palmar burn scar contractures in pediatric patients are compared. Patients treated with full-thickness skin grafts required 1.2 +/- 0.4 operations (mean +/- SD). Patients treated with split-thickness skin grafts required 1.3 +/- 0.6 operations (mean +/- SD). No significant difference in the number of operative procedures was noted. No functional difference existed between the two groups. The use of split-thickness skin grafts provided comparable function without increased operative procedures and was less deforming. Increased use of split-thickness skin grafts following release of palmar burn scar contractures in pediatric patients should be considered.

Burns↗
PubMed1987

Routine use of a suction drain in facial rhytidoplasty.

The effectiveness of a suction drain in facial rhytidoplasty was evaluated in 46 women ranging in age from 41 to 78 years. The drain was placed on the left side of the face in 16 and on the right in 14, and no drain was used in 16 patients. The drain was removed in 24 hours regardless of the amount aspirated, which varied between 0 and 25 ml, with an average of 7.8 ml. Although none of these patients developed a hematoma while the drain was in place, a hematoma did occur in 1 patient on the drain side following its removal. Despite the variable quantities of fluid aspirated, there was no clinical difference in swelling noted around the face and neck area when the two sides were compared. Similarly, one could not distinguish this group of patients from those 16 who did not receive the drain. The routine use of continuous suction drains for patients undergoing rhytidoplasty is therefore probably unnecessary.

Adult↗
PubMed1986

Restoration of the upper lip and nasolabial area by means of an intraoral approach.

Superomedial repositioning of the superficial musculoaponeurotic system (SMAS) in the upper lip is accomplished by means of intraoral incisions. The procedure reestablishes the convexity of the lateral vermilion border, elevates the upper lip, and restores a more youthful appearance to the upper-lip profile. Depth of the nasolabial folds are reduced. We have performed this procedure on 14 patients. Follow-up intervals range from 6 to 20 months, averaging 14 months. All patients received concomitant rhytidectomy; usual operative time was increased by 20 minutes. Results have been rated good to excellent by patients and surgeons. There have been no recurrences of nasolabial fold deepening or upper lip depression, and there have been no complications. In selected patients, this procedure, along with rhytidectomy, may provide a more youthful appearance.

Female↗
PubMed1986

The quality of life after major thermal injury in children: an analysis of 12 survivors with greater than or equal to 80% total body, 70% third-degree burns.

Twenty-one children admitted between December 1981 and May 1985, with greater than 80% total body surface area burn (TBSAB), underwent total excision and grafting of all of their wounds within 72 hours of injury. Twelve survivors (with an average TBSAB of 89%, 82% third degree) were studied in detail describing the length of hospital stay (77 +/- 10 days), number of operative procedures (7.8 +/- 0.8), total blood loss (12 +/- 2 blood volumes), the number of patients who experienced septic episodes (three), the number of patients who required amputation (four), range of motion, degree of scarring, ability to perform daily activities, and psychological adjustment. Physical impairment, according to standard scales, was approximately 60%; however, 50% of the children old enough to be tested were completely independent in activities of daily living. One third of the children had excessive fear, regression, and neurotic and somatic complaints, but all of them showed remarkable energy in adapting to their disabilities. We conclude that the final outcome, for these patients, can only be assessed as they achieve late adolescence and young adulthood.

Activities of Daily Living↗
PubMed1982

A circumareolar approach in surgical management of gynecomastia.

Gynecomastia is a common deformity encountered among male patients. Surgery is primarily aimed at reducing the size of the breast mound and therefore should be considered aesthetic in nature. In an attempt to minimize the problems of hematoma formation, nipple necrosis, and unsightly scarring around the upper torso after the surgery, we have had the opportunity to utilize a circumareolar approach for breast tissue removal in 33 breasts (24 patients). This method, when compared with other techniques, has the advantage of leaving minimal scarring around the areolar margin while obliterating the dead space by imbricating the tissue stalk to minimize hematoma formation.

Adolescent↗
PubMed1981

A histological study of the lower tarsus and the significance in the surgical management of a involutional (senile) entropion.

The dimension of the lower tarsus diminishes with aging. Changes in the number and size of the meibomian glands and in the character of intermingling fibroconnective tissues are thought to be responsible. Furthermore, such alterations of the structural integrity play an important role in the pathogenesis of entropion encountered commonly in the elderly. We have advocated the use of an autogenous cartilage graft harvested from the ear to correct the deformity, especially in instances where the conventional methods of correction have failed.

Aged↗
PubMed1979

Hats for the newborn infant.

The efficacy of a Gamgee-lined hat in reducing the rate of fall in rectal temperature of infants during the first 30 minutes of life was studied. The trial, which included 211 infants, was randomised, prospective, and controlled. One hundred and seven infants were exposed to overhead radiantheaters. Of these, only 30 had normal deliveries, so the analysis was confined to the infants who were not subjected to radiant heat, and in this group no conclusions were drawn about the efficacy of a hat or a radiant heater. In the 104 infants not subjected to radiant heat, body weight, initial rectal temperature, the application of hat, the environmental temperature, and the duration of exposure while naked were all found to influence measureably the rate of fall in rectal temperature during the first 30 minutes. Gamgee-lined hats should be routinely used to minimise heat loss, especially in small infants exposed at birth, during surgical operations, and during investigations necessitating prolonged exposure.

Body Temperature↗
PubMed1979

Outpatient breast surgery under intercostal block anesthesia.

During the past 3 years, we have performed various breast operations in 320 patients under local anesthesia, using intercostal nerve block. The amount of local anesthetic solution required has been about 20 ml 1% lidocaine for blocking both sides, and an additional 24 ml of 0.5% lidocaine during the surgery. This dosage is well within safe limits. We have found that various breast operations, ranging from augmentation mammaplasty to a staged reconstruction after mastectomy, can be done with this method of anesthesia. The complications attributable to the nerve block were nil in our series.

Ambulatory Care↗
PubMed1978

Ten years of experience in managing patients with burn contractures of axilla, elbow, wrist, and knee joints.

An analysis of 625 patients who had sustained burns across the axillae, elbows, wrists, or knee joints indicates that the use of splints and pressure across these joints will not only greatly decrease the incidence of contractures but will also reduce the frequency and need for release operations. However, these appliances must be used for at least 6 months (longer, if possible), if substantial benefits are to be obtained.

Axilla↗