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Biomedical subjects

D K Lewis

Publications and source records attributed to D K Lewis.

At least 19 recordsLinked to original sources
PubMed2004

cDNA cloning and transcriptional regulation of the vitellogenin receptor from the imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae).

We describe the cloning of the first hymenopteran vitellogenin receptor (VgR) cDNA from the imported fire ant, Solenopsis invicta, an invasive pest. Using reverse transcription polymerase chain reaction and rapid amplification of cDNA ends, fragments encompassing the entire coding region of a putative VgR were cloned and sequenced. The complete 5764 bp cDNA encodes a 1782 residue protein with a predicted molecular mass of 201.3 kDa (=SiVgR). Northern blot analysis demonstrated that the 7.4 kb SiVgR transcript was present only in ovaries of reproductive females (virgin alates and queens). The temporal profile of transcriptional expression showed that SiVgR mRNA increased with age in virgin alate females and that this was up-regulated by methoprene, a juvenile hormone (JH) analogue. This suggests that the SiVgR gene is JH regulated.

Age Factors↗
PubMed2002

Ocular disease in patients with tuberculosis and HIV presenting with fever in Africa.

AIMS: To investigate ocular disease in patients with tuberculosis (TB) and HIV in Africa presenting with fever, and to determine if indirect ophthalmoscopy is useful in the diagnosis of mycobacteraemia. METHODS: A prospective study of all adult patients admitted with fever to a large central hospital in Malawi, Africa. All recruited patients had an ophthalmic examination, HIV tests, chest x ray, sputum examinations, bacterial and mycobacterial blood cultures, and malaria slide to observe the presence of parasites. RESULTS: 307 patients were recruited; 109 (36%) had TB, including 53 (17%) with mycobacteraemia; 255 (83%) had HIV and 191 (62%) had AIDS. Of the patients with TB 102 (94%) had HIV. Choroidal granulomas were found in four patients, all of whom had AIDS; three (2.8% of those with TB) had disseminated TB with mycobacteraemia, and one had persistent fever but no other evidence of TB. Among the patients with AIDS, 32 (17%) had microangiopathy manifest by cotton wool spots; one (0.5%) had signs of active cytomegalovirus (CMV) retinitis. The presence of microangiopathy was not related to TB. CONCLUSIONS: In Malawian patients with TB presenting acutely with fever, choroidal granulomas were found in 2.8%, and were concurrent with mycobacteraemia and AIDS. Ophthalmoscopy was not a useful aid in the diagnosis of mycobacteraemia. Cytomegalovirus (CMV) retinitis is rarely seen in African AIDS patients. This may be the result of mortality early in the disease course, or differences in race, HIV subtype, or comorbidity.

Acquired Immunodeficiency Syndrome↗
PubMed2002

Clinical indicators of mycobacteraemia in adults admitted to hospital in Blantyre, Malawi.

SETTING: Adult medical wards of a central hospital in Blantyre, Malawi. OBJECTIVE: To measure the prevalence and outcome of mycobacteraemia in febrile hospitalised adults, and to determine what proportion could be identified using routine methods; to assess clinical indicators of mycobacteraemia, and the usefulness of a diagnostic trial of anti-tuberculosis treatment. DESIGN: We prospectively examined adults admitted with fever or a history of fever. All had blood cultured for bacteria and mycobacteria, chest X-ray and sputum smears. FINDINGS: Mycobacterium tuberculosis was the commonest cause of blood stream infection (BSI), affecting 57 of 344 patients (17%). In 44 (77%) patients with mycobacteraemia, TB was identified using routine investigations; it was not suspected in six (11%). Strong clinical indicators of mycobacteraemia were anaemia, HIV seropositivity, cough, chronic fever and a clinical diagnosis of AIDS on the day of admission. Of nine patients selected for a therapeutic trial of tuberculosis (TB) treatment, six had mycobacteraemia, of whom five died during the trial. Mortality on short-course chemotherapy, on the TB ward after 1 month was similar whether patients had mycobacteremia (21%) or not (32%). CONCLUSION: TB can be identified with routine methods in most patients with mycobacteraemia. If treated, mycobacteraemia has as good an early outcome as TB without mycobacteraemia. Strengthening of basic facilities is likely to improve detection and treatment of mycobacterial disease.

Adolescent↗
PubMed2001

Anthropometric correlates of basketball free-throw shootings by young girls.

The purpose of this analysis of data from a larger investigation was to assess effects of anthropometric factors on free throw shooting performance of 15 girls from Michigan and 18 from Puerto Rico. Subjects performed 60 free throws (10 trials x 3 ball sizes x 2 basket heights). Correlations were low, with two exceptions, .53 between shooting performance at the low basket and grip strength (as measured by hand grip dynamometer) for girls from Michigan, and .49 for hand width and performance at the low basket for girls from Michigan.

Anthropometry↗
PubMed1997

Hypertrehalosemic hormone in a cockroach: molecular cloning and expression.

Hypertrehalosemic hormone (HTH) is a neuropeptide in the adipokinetic hormone/red pigment-concentrating hormone (AKH/RPCH) family that stimulates the synthesis of trehalose, the main blood sugar of many insects. The preproHTH of the cockroach Blaberus discoidalis was cloned from the corpora cardiaca (CC), the endocrine source for HTH, and the deduced sequence and organization of preproHTH were compared with other AKH/RPCH precursors. PreproHTH mRNA was determined to be approximately 0.5 kb in length as predicted by DNA sequence analysis. Northern blot analysis of the CC, ventral nerve cord, brain and fat body detected HTH-mRNA only in the CC. Levels of the HTH transcript in the CC were determined according to age, gender and mating. The HTH message was most abundant in the CC during the first several days of adult life in both sexes, then declined by 50% and were stable. HTH-mRNA levels in the CC did not respond to mating.

Aging↗
PubMed1994

Laparoscopic cholecystectomy: laser or electrocautery?

Laparoscopic cholecystectomy is now an accepted part of general surgery. With the recent upsurge of interest in laparoscopic techniques, an optimum method of ensuring secure haemostasis is important particularly during dissection of the gall bladder from its mesenteric attachments. The use of laser to ensure haemostasis has been well practised in the treatment of peptic ulceration. Electrocautery is a time-honoured method of controlling local bleeding points by coagulation of tissue. The aim of this study was to assess whether one procedure showed any advantage over the other in terms of the length of operation time, postoperative drainage volume, time to dissect the gall bladder and length of the hospital stay.

Adult↗
PubMed1994

Sexual behavior and sexual identity in male injection drug users.

Sexual behavioral data from a survey of 396 male drug injectors showed that 301 (76%) were behavioral heterosexuals, 49 (12.45%) were bisexuals, and 46 (11.6%) were homosexuals over the previous 5 years. Among those sexually active during the 6 months before the interview, bisexuals were similar to heterosexuals and homosexuals in reporting two or more female or male partners, respectively. Overall, almost three fourths of the bisexuals had two or more sexual partners. Bisexuals were also similar to heterosexuals in reported heterosexual and intercourse (16 and 15%, respectively), and to homosexuals in reported homosexual insertive anal intercourse (33 and 54%, respectively). They were less likely than heterosexuals to engage in vaginal and insertive oral sex with women and than homosexuals to practice receptive and and oral sex with men. The three groups all practiced high levels of unprotected sex. Almost half the behavioral bisexuals identified themselves as heterosexuals. Self-identified heterosexuals in the sample were less likely than self-identified gays or bisexuals to state they reduced sexual risk; however, reported condom use was low for all three groups. With human immunodeficiency virus infection rates of 54% (21 of 39) for behavioral homosexuals, 24% (11 of 45) for bisexuals, and 9% (24 of 260) for heterosexuals, these findings indicate an urgent need for more effective sexual risk reduction among injection drug users and their partners.

Adult↗
PubMed1991

Sexual risk behavior among heterosexual intravenous drug users: ethnic and gender variations.

We analyzed the relationship of ethnicity and gender to high-risk sexual behavior among 457 male and female heterosexual intravenous drug users (IVDUs) interviewed in street and clinic settings in San Francisco. Over two-thirds said they never used condoms. More of the black respondents had not been enrolled in treatment. White IVDUs were more likely to report 10 or more partners, anal sex, and a steady drug-injecting partner; black respondents more often reported prostitution. More men said they never used condoms, and more women said they engaged in prostitution. These high-risk sexual behaviors were significantly and independently associated with ethnicity or gender when other sociodemographic variables were held constant. Sexual risk reduction for IVDUs, focusing on condom use, needs to be expanded to reach non-injecting partners. Intervention is critical for the black community, where a high proportion of IVDUs have steady non-injecting partners.

Adult↗
PubMed1990

The "clam": indications and complications.

We have reviewed 78 patients who underwent "clam" enterocystoplasty as part or all of their lower urinary tract reconstruction. Nearly half (32) were non-neuropathic; the remainder were either overtly neuropathic (mainly spina bifida) or suspected neuropathic (mainly the older primary enuretics). Only 5 were non-walkers--all neuropathic. Most patients were operated on for incontinence but 12 had upper tract damage related either to urinary diversion or to poor bladder compliance in the early phase of filling; 69 patients became dry, voiding spontaneously (30), by activation of an artificial urinary sphincter (17) or by self intermittent catheterisation (22). Four patients still have nocturnal enuresis, 3 diurnal enuresis and 2 have stress incontinence. One patient has had a continent diversion. The "clam" procedure has revolutionised bladder reconstruction. Careful review has failed to predict the small number who do not achieve a perfect result.

Adolescent↗
PubMed1990

The prevalence of high-risk sexual behavior in male intravenous drug users with steady female partners.

A sample of 149 (70 White, 79 Black) male intravenous drug users with steady female sexual partners was interviewed in 1987, in treatment and street settings, about sexual practices during the previous five years. Eighty-three percent had multiple partners, 15 percent reported male sexual contact, 38 percent reported heterosexual anal intercourse, and 73 percent never used condoms. Thirty-seven White and 30 Black subjects reported bisexuality or heterosexual and intercourse or both.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Human immunodeficiency virus seroprevalence in female intravenous drug users: the puzzle of black women's risk.

This study of 155 female i.v. drug users found that black women had higher HIV seroprevalence than white women (21% compared to 7%, respectively, odds ratio = 3.59, 95% CI 1.28-9.98). To attempt to explain why black female i.v. drug users were more likely to test HIV antibody positive, the ethnic distribution of a series of risk factors associated with HIV seropositivity, such as needle sharing, high risk sexual behavior and history of sexually transmitted disease, was examined. Either there was no significant difference between the two groups or white i.v. drug users were more likely than blacks to engage in specific risk behaviors. Although this study failed to identify risk factors associated with higher HIV seropositivity in black female i.v. drug users, it did uncover important trends in the data. These trends are analyzed in terms of observed or possible social and cultural differences between black and white women. It is suggested that these underlying social and cultural differences may hold the key to black female i.v. drug users' greater risk of HIV infection.

Adult↗
PubMed1981

Matching in epidemiologic studies: validity and efficiency considerations.

Validity and efficiency issues are considered with regard to the use of matching and random sampling as alternative methods of subject selection in follow-up and case-control studies. We discuss the simple situation involving dichotomous disease and exposure variables and a single dichotomous matching factor, and we consider the influence on efficiency of a possible loss of subjects due to matching constraints. The decision to match or not should be motivated by efficiency considerations. An efficiency criterion based on a comparison of confidence intervals under matching and random sampling for the effect measure of interest (the risk ratio and risk difference in follow-up studies, and the odds ratio in case-control studies) leads to the following conclusions when the sampling method does not influence the size of the comparison group. In follow-up studies, matching on a confounder is expected to lead to a gain in efficiency over random sampling, while matching on a nonconfounder is not expected to result in a loss of efficiency. In case-control studies, the same conclusions hold, except that matching is not as advantageous as in follow-up studies and can lead to a loss of efficiency in some situations (usually of little practical importance). When matching reduces the size of the comparison group, there is likely to be a meaningful gain in efficiency due to random sampling only when the matched comparison group is at most 40-50% the size of the randomly-sampled comparison group is a follow-up study, and at most 50-65% the size in a case-control study.

Follow-Up Studies↗