Biomedical subjects

B Katz

Publications and source records attributed to B Katz.

At least 19 recordsLinked to original sources

PubMed2001

Subsequent sexually transmitted infection in urban adolescents and young adults.

OBJECTIVE: To compare the rates of subsequent infection with Chlamydia trachomatis, Neisseria gonorrhoeae, or Trichomonas vaginalis in a group of high-risk adolescents and young adults. METHODS: At the time of treatment, 444 unmarried teenagers and young adults aged 13 to 25 years were enrolled from an urban sexually transmitted disease clinic and 3 community-based primary care clinics. Subjects were infected with C trachomatis, N gonorrhoeae, or T vaginalis, were diagnosed as having nongonococcal urethritis (in men), or were uninfected sexual contacts with one of these infections. Subjects returned at 1, 3, 5, and 7 months. RESULTS: The rate of subsequent infection was substantial. Forty percent of men and 53% of women who were uninfected contacts at enrollment were estimated to be infected within 7 months; 60% of men and 73% of women infected at enrollment were estimated to be reinfected. Among women, subjects who were infected at enrollment had a shorter time to subsequent infection (median, 140 days) compared with uninfected contacts (median, 209 days) (P =.04). Among men, findings were similar, but the difference in median time to subsequent infection was not significant (P =.08). Baseline characteristics that predicted shorter time to reinfection were female sex and infection at enrollment. When sexual behaviors in the 2 months preceding each subsequent data collection visit were included in the model, only being female and reporting at least one new interval sexual partner were significant predictors of subsequent sexually transmitted infections. CONCLUSIONS: These data support recent research that has found high rates of subsequent infection among high-risk adolescents and young adults. Contacts of a sexually transmitted infection appear to be at equally high risk for subsequent infection as those with a personal history of infection. Our data suggest that more frequent than annual screening for N gonorrhoeae, C trachomatis, and T vaginalis would be appropriate in at-risk adolescent and young adult populations, including individuals who are uninfected sexual contacts to a sexually transmitted infection.

Adolescent↗

PubMed2001

Introduction to dermoscopy.

When approaching a pigmented lesion with dermoscopy, the entire architecture of the lesion should be considered. The presence of certain pigment patterns, structural patterns, or border characteristic alone are insufficient to make the most accurate diagnosis. Because pigmented lesions are dynamic and have many variations in their patterns, there can exist no exact defining classifications among each type of pigmented lesion.

Diagnosis, Differential↗

PubMed2001

Dermatoscopy of lentigo maligna.

Lentigo maligna and LMM require different dermatoscopic criteria for evaluation. The ease and accessibility of examining these lesions with dermatoscopy coupled with the clinical pathologic correlation afforded by the biopsy techniques discussed allow the practitioner to become proficient and prescient with the use of dermatoscopy. The criteria mentioned here are relatively new but are present and detectable in most cases of LM and LMM. The fact that there is some overlap among pigmented actinic keratosis, squamous cell carcinoma in situ, and lichenoid keratosis lesions should not detract or deter the physician from using dermatoscopy. Clinically, these lesions also usually will be equivocal and will require close clinical scrutiny and biopsies. If given the choice of using skin surface microscopy for one class of lesion only, one might well choose LM lesions because of their otherwise subtle nature and the clues that can be unlocked with oil immersion, illumination, and magnification, along with knowledge of these new criteria.

Dermatology↗

PubMed2001

The efficacy of powered liposuction.

BACKGROUND: Powered liposuction is a relatively new innovation for more efficient removal of adipose tissue. OBJECTIVE: To evaluate the effectiveness of powered liposuction in removing adipose tissue when compared to traditional liposuction. METHODS: Four powered liposuction devices were evaluated in the power on mode vs. the power off. The fat extracted in each of these modes was measured in a mucous specimen trap. RESULTS: There was increased fat extraction in the powered mode for all instruments. The increased rate of fat extraction varied from 20 to 45% between instruments. the overall increased extraction in powered vs. nonpowered mode was 30%. CONCLUSION: The powered liposuction devices tested significantly increase the efficacy of subcutaneous fat removal during liposuction.

Abdomen↗

PubMed2001

Self-effacing wit as a response to oppression: dynamics in ethnic humor.

Theories of self-effacing ethnic humor are analyzed from the perspectives of psychological defense and acculturation. These processes are contrasted with masochism as explanations of self-directed wit. Developmental paradigms are appealed to in conceptualizing the sociocultural function of humor. Identification with the aggressor is conceptualized as a transitional mechanism to assimilate the minority into the host culture. Turning against the self is developed as an alternate mechanism that uses humor as a means of self-empowerment. Reframing and splitting are posited as integral to the defensive process of ethnic humor. The method of luring the aggressor into a situation that is then used against him is construed as the kamikaze maneuver and conceptualized as an ambush technique in which the role of self-effacement facilitates aggression. The analytic elements of these approaches are explored with reference to Jewish humor as a stereotype of the wit of a transient and oppressed people, and annotated examples are offered from published anthologies. Illustrative vignettes, ranging from the mundane to the clinical, are annotated in the discussion. Directions for further inquiry are outlined for issues unresolved in the research literature.

Defense Mechanisms↗

PubMed2001

Effect of methyldopa on renal function in rats with L-NAME-induced hypertension in pregnancy.

BACKGROUND: Pregnancy-induced hypertension is characterized by an increased sympathetic activity and probably by a decreased synthesis/activity of nitric oxide. The aim of the present study is to evaluate whether the beneficial action of the sympathetic antagonist methyldopa (a first-choice hypotensive agent in the treatment of PIH) may be associated to changes in nitric-oxide synthesis. METHODS: Forty pregnant Wistar rats received L-NAME (NO synthase inhibitor, 9-10 mg/kg/day) from mid-pregnancy (day 11) through to term. Some rats were treated with daltroban (TxA receptor antagonist, 60 mg/kg/day), diltiazem (calcium channel blocker, 30 mg/kg/day), methyldopa (central adrenergic antagonist, 400 mg/kg/day) or L-arginine (260 mg/kg/day) from mid-pregnancy. The effect of the different treatments on systolic blood pressure (SBP), creatinine clearance (CCR), urine protein excretion (UP) and urinary nitrate excretion (UNO(3), representing urine NO metabolite) were evaluated and the results compared with those found in normal pregnancy. Normal pregnant rats receiving similar treatment were used as controls. RESULTS: In normal pregnant (P) rats, SBP values decreased from 94 +/- 2 to 83 +/- 3 mm Hg at the end of pregnancy (p < 0.01) and CCR augmented significantly. Drug treatment had no significant effect. In NAME-treated rats, at the same period, the SBP augmented from 92 +/- 1 to 129 +/- 1.8 mm Hg (p < 0.01). At the end of pregnancy, NAME rats had significantly lower CCR values and higher UP excretion when compared with P rats. UNO(3) increased significantly in P and in P rats treated with methyldopa. As expected, in NAME rats UNO(3) excretion was significantly reduced. Treatment with methyldopa normalized SBP, improved CCR and proteinuria and was associated with an increase in UNO(3). Similar results were obtained with L-arginine treatment. Diltiazem lowered SBP significantly but had no effect on renal function or UNO(3) and daltroban had no effect. CONCLUSION: The increased UNO(3) found in NAME rats treated with methyldopa suggests that the vasoconstriction secondary to chronic NO inhibition may be partially related to an increased sympathetic activity. The efficient action of the sympathetic antagonist methyldopa may be due not only to its antihypertensive effects but also by its stimulating effect on NO synthesis leading also to an improvement of renal function.

Animals↗

PubMed2001

Chronic exogenous hyperinsulinaemia-induced hypertension in pregnant rats: effect of chronic treatment with l-arginine.

Recent studies have shown that maternal hyperinsulinaemia is a risk factor for the development of hypertension in pregnancy. Experimentally, pregnant rats with chronic exogenously induced hyperinsulinaemia (P-INS rats) have increased blood pressure at the end of gestation. This is associated with a blunted elevation of the excretion of the urinary metabolites of nitrate (UNO(x)). In the present study, we aimed to evaluate the mechanism(s) of the increase in blood pressure in this model. Four groups were studied: normal pregnant rats (P rats), P-INS rats, P-INS rats treated with L-arginine (2 g/l in the drinking water) (L-ARG rats) and hyperinsulinaemic virgin rats (V-INS rats). Systolic blood pressure (SBP), UNO(x) excretion (on ingestion of a controlled low-nitrate diet), urine noradrenaline (norepinephrine) and plasma endothelin levels were evaluated. Rats were killed on day 22 of pregnancy. Five P-INS rats were not killed at this time, in order to measure SBP 30 and 60 days after delivery. Fetal number and fetal body weight were evaluated. At the end of pregnancy, a 10+/-3% increase in SBP was found in P-INS rats, contrasting with a fall of -15+/-4% in P rats (P<0.01). In the L-ARG group at the end of pregnancy, SBP values had fallen by -14+/-2%, to values comparable with those of P rats. The increase in UNO(x) excretion was 175+/-38% in P rats, 106+/-12% in L-ARG rats and 41+/-8% in P-INS rats (P<0.01 compared with P and L-ARG groups). No differences were found in the urinary excretion of noradrenaline or in the plasma levels of endothelin-1 between the pregnant groups. Fetal number was similar in all groups, but fetal body weight was lower for P-INS rats compared with P and L-ARG rats. Thus the blood pressure response to L-arginine strongly suggests that a decrease in NO availability may be the main pathogenic mechanism involved in the development of hypertension in this model.

Animals↗

PubMed2001

Tubed gastro-omental free flap for pharyngoesophageal reconstruction.

BACKGROUND: Malignant lesions of the pharyngoesophagus often require total laryngopharyngectomy and mediastinal dissection. As a result of the current treatment paradigms for advanced laryngopharyngeal cancers, it is common that the surgical field has been previously irradiated or exposed to systemic chemotherapy, resulting in fistula rates as high as 78% and mortality as high as 8%. The free vascularized tubed gastric antrum and the accompanying greater omentum offer a single-staged method of pharyngoesophageal reconstruction, with the added benefit of protection of the great vessels, the tracheal stump, and the mediastinal contents in a high-risk surgical field. OBJECTIVE: To assess the gastro-omental free flap as a method of pharyngoesophageal reconstruction in patients who have been previously treated with multimodality therapy. METHODS: Five consecutive cases of gastro-omental free flap reconstruction after total laryngopharyngectomy were retrospectively reviewed. Each case was assessed for intraoperative, perioperative, and postoperative complications at the primary site of reconstruction and the donor site. Patients were also evaluated for their ability to maintain an oral diet. Patients were followed up for a minimum of 6 months after surgery. RESULTS: Five patients aged 44 to 70 years (mean, 59 years) underwent gastro-omental free flap reconstruction after total laryngopharyngectomy. Five patients had received previous external beam irradiation, 2 had received systemic chemotherapy, and 4 had undergone previous surgery. There were no fistulae or flap complications. Three patients were successfully treated with esophageal dilation for strictures sustained 2 to 5 months after surgery, and a third patient was successfully treated with conservative management for a partial gastric outlet obstruction sustained 2 months after surgery. One patient died 3 months after surgery of distant metastatic disease. The remaining 4 patients currently tolerate an oral diet. CONCLUSION: The tubed gastro-omental free flap offers a safe method of reconstructing the pharyngoesophageal segment in a surgical field compromised by previous multimodality therapy.

Adult↗

PubMed2000

Surface microscopy of pigmented basal cell carcinoma.

OBJECTIVES: To describe the relevant morphologic features and to create a simple diagnostic method for pigmented basal cell carcinoma (BCC) using in vivo cutaneous surface microscopy (ie, dermoscopy, dermatoscopy, or oil epiluminescence microscopy). DESIGN: Pigmented skin lesions were photographed in vivo using immersion oil (surface microscopy). All pigmented skin lesions were excised and reviewed for histological diagnosis. Photographs of 142 pigmented BCCs, 142 invasive melanomas, and 142 benign pigmented skin lesions were randomly divided into 2 equally sized training and test sets. Images from the training set were scored for 45 surface microscopy features. From this a model was derived and tested on the independent test set. SETTING: All patients were recruited from the primary case and referral centers of the Sydney Melanoma Unit, Sydney, Australia, and the Skin and Cancer Unit, Skin and Cancer Associates, Plantation, Fla. PATIENTS: A random sample (selected from a larger database) of patients whose lesions were excised. MAIN OUTCOME MEASURES: Sensitivity and specificity of the model for diagnosis of pigmented BCCs. RESULTS: The following model was created. For a pigmented BCC to be diagnosed it must not have the negative feature of a pigment network and must have 1 or more of the following 6 positive features: large gray-blue ovoid nests, multiple gray-blue globules, maple leaflike areas, spoke wheel areas, ulceration, and arborizing "treelike" telangiectasia. On an independent test set the model had a sensitivity of 97% for the diagnosis of pigmented BCCs and a specificity of 93% for the invasive melanoma set and 92% for the benign pigmented skin lesion set. CONCLUSION: A robust surface microscopy method is described that allows the diagnosis of pigmented BCCs from invasive melanomas and benign pigmented skin lesions. Arch Dermatol. 2000;136:1012-1016

Basal Cell Carcinoma↗

PubMed2000