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Biomedical subjects

J D Klein

Publications and source records attributed to J D Klein.

At least 37 records · Page 2Linked to original sources
PubMed2001

Care of the adolescent sexual assault victim.

Sexual assault is a broad-based term that encompasses a wide range of sexual victimizations, including rape. Since the American Academy of Pediatrics published its last policy statement on this topic in 1994, additional information and data have emerged about sexual assault and rape in adolescents, the adolescent's perception of sexual assault, and the treatment and management of the adolescent who has been a victim of sexual assault. This new information mandates an updated knowledge base for pediatricians who care for adolescent patients. This statement provides that update, focusing on sexual assault and rape in the adolescent population.

Adolescent↗
PubMed2001

Where are we on teen sex?: Delivery of reproductive health services to adolescents by family physicians.

BACKGROUND AND OBJECTIVES: This study describes variation in reproductive health preventive services delivery to adolescents by family physicians in Upstate New York. METHODS: We surveyed a stratified random sample of 354 family physicians from three New York State metropolitan statistical areas about the proportion of their adolescent patients (ages 15-18) to whom they deliver preventive reproductive health interventions. Responses were averaged to create a preventive care practice score. RESULTS: Of 295 eligible respondents, 179 returned completed surveys (61%). Eighty-one percent were male. Respondents did not vary by geographical area. However, female family physicians were less likely to respond than males, and olderfamily physicians were less likely to respond than more-recent graduates. On average, family physicians reported asking 79% of their adolescent patients about contraceptive use, 73% about condom use, 72% about sexual relationships, and 61% about sexual behaviors. Only 36% reported asking teens when they thought sex was appropriate, and 30% had discussed sexual orientation. Seventy-six percent of physicians discussed adolescents' risks of HIV with adolescent patients, 78% advised adolescent patients to use condoms, 21% gave handouts about HIV, and 9% gave condoms to adolescent patients. Factors associated with provision of more preventive reproductive services included regularly discussing confidentiality, more-recent medical school graduation, placing a high value on the American Academy of Family Physicians recommendations, having read Centers for Disease Control immunization guidelines, having read American Academy of Pediatrics guidelines, and female gender Overall, these factors explained 26% of the variance in provision of preventive reproductive services. CONCLUSIONS: Family physicians report providing most reproductive preventive services to more than half of their patients. Female physicians, older physicians, physicians who regularly discuss confidentiality, and physicians who have a more-positive attitude toward andfamiliarity with preventive care guidelines are more likely to provide reproductive health screening and counseling during adolescent visits.

Adolescent↗
PubMed2000

Surface-enhanced raman detection of 2,4-dinitrotoluene impurity vapor as a marker to locate landmines.

Time, cost, and casualties associated with demining efforts underscore the need for improved detection techniques. Reduction in the number of false positives by directly detecting the explosive material, rather than casing material, is desirable. The desired field sensor must, at a minimum, demonstrate reproducibility, the necessary level of sensitivity, portability, instrumental stability, and fast system response times. Ideally, vibrational spectroscopic techniques have the potential to remove false positives, since every chemical has a unique bond structure. Herein, we demonstrate the capabilities of surface-enhanced Raman spectroscopy to detect the chemical vapor signature emanating from buried TNT-based landmines. We present reproducible results obtained from blind tests controlled by the Defense Advanced Research Projects Agency (DARPA) that demonstrate vapor detection of 2,4-dinitrotoluene at concentration levels of 5 ppb or less. The results presented used acquisition times of 30 s on a fieldable system and showed that SERS can be a significant improvement over current landmine detection methods.

Journal Article↗
PubMed2000

Health-compromising behaviors: why do adolescents smoke or drink?: identifying underlying risk and protective factors.

OBJECTIVES: To better understand the motivation for adolescent smoking and drinking and to identify the underlying risk and protective factors associated with these behaviors among adolescents. DESIGN: Cross-sectional, school-based survey of students in grades 5 through 12. PARTICIPANTS: A nationally representative sample of 2574 boys and 2939 girls in grades 7 through 12 from 297 public, private, and parochial schools across the United States who participated in The Commonwealth Fund Survey of the Health of Adolescent Girls and Boys in 1997. MAIN OUTCOME MEASURES: Sex-specific adjusted relative risks (RRs) and 95% confidence intervals (CIs) comparing self-reported regular smokers and regular drinkers by risk and protective factors with adolescents reporting none of these behaviors. RESULTS: Adolescent boys and girls were equally likely to be regular smokers (11.2%). The prevalence rate of regular drinking was only slightly higher for boys (22.4%) than it was for girls (19.3%). The rates of both health-risk behaviors were significantly higher for those reporting risk factors, and the strengths of associations varied by sex. Sex differences also emerged in motivation for engaging in these behaviors. When we adjusted for demographic characteristics, exposure to childhood abuse (RR, 4.1; 95% CI, 2.4-7.0) and stressful life events (RR, 2.4; 95% CI, 1.1-5.4) were strongly associated with increased risk for boys' regular smoking. Similar associations were found for regular drinking. For girls, a history of abuse (RR, 1.8; 95% CI, 1.1-2.8), violence within the family (RR, 2.2; 95% CI, 1.6-3.2), depressive symptoms (RR, 1.6; 95% CI, 1.0-2.4), and stressful life events (RR, 3.1; 95% CI, 1.8-5.6) were significantly associated with increased risk for regular smoking. Similar associations were again found for regular drinking. Parental support was protective against both health-risk behaviors for both sexes. Participation in extracurricular activities was associated with lower risk for regular smoking for boys (RR, 0.4; 95% CI, 0.2-0.7) and for girls (RR, 0.3; 95% CI, 0.2-0.5); however, there was no significant association between drinking behavior and participation in activities. CONCLUSIONS: The increased risk for regular smoking and regular drinking among adolescents with a history of abuse, family violence, depressive symptoms, and stressful life events suggests that routine screening for abuse, violence, and other family experiences should be an essential component of adolescent health care visits. Effective prevention programs to reduce smoking and drinking among adolescents should recognize that health-risk behaviors may be associated with other negative life experiences and that the strength of these associations differs by sex.

Adolescent↗
PubMed2000

Adolescents who use the emergency department as their usual source of care.

OBJECTIVE: To examine the factors associated with use of the emergency department (ED) as the only source of health care among adolescents. DESIGN: Analyses of the 1997 Commonwealth Fund Survey of the Health of Adolescent Girls, a nationally representative sample of 6748 in-school male and female adolescents in 5th through 12th grade. The X2 statistics and logistic regression analyses were computed with the use of SUDAAN. RESULTS: Overall, 4.6% of the adolescents in the survey, or 1.5 million adolescents in the United States, reported that the ED was their usual source of health care. In multivariate models, factors associated with the use of the ED included male sex, African American ethnicity, fewer financial resources, and living in a rural area. Adolescents with higher levels of risky behaviors, a history of physical or sexual abuse, and higher depression scores were all more likely to use the ED as their usual source of care. Adolescents who reported using the ED as their usual care source were also less likely to have had regular well visits and were more likely to report having missed needed care than those with other sources of primary care. CONCLUSIONS: Adolescents who use the ED as their usual source of care are often from vulnerable populations. Many have special mental or physical needs that are unlikely to be met with ED visits only, and they are likely to have missed care they needed. Creating linkages between EDs and other services could help at-risk adolescents identify and use more appropriate sources of primary care.

Adolescent↗
PubMed2000

Homeless and runaway youths' access to health care.

PURPOSE: To describe use of health services and self-reported access to regular and emergency care by homeless adolescents and street youth. METHODS: Interviewer-administered surveys addressed use of health services, availability of sources of care for emergencies, and types of care sources used. An abbreviated version of the questionnaire used for youth in shelters was used for street youth. A nationally representative sample of 640 sheltered youth and a purposive sample of 600 street youth aged 12-21 years were interviewed. All data were collected in 1992. RESULTS: Half of street youth and 36% of sheltered youth did not have a regular source of health care (p < or =.05). One-fourth of street youth and 18% of sheltered youth also reported serious health problems within the past year (p < or =.05). Street youth were more likely than sheltered youth to have used emergency treatment (36% vs. 29%; p < or =.05) and alcohol- or drug-related emergency treatment (25% vs. 13%; p < or =.05). Sheltered youth with a regular source of care were more likely to use nonemergency sites than those without a source of primary care (46% vs. 20%; p < or =.001). Few sheltered or street youth perceived shelter clinics, clinics for runaway youth, or free youth clinics to be available to meet their emergency care needs. CONCLUSIONS: Significant numbers of homeless youth did not have a regular source of health care. Those who had a regular source of care were more likely to have continuity between routine and emergency care. Integration of health services with other agencies serving youth in shelters or on the street may improve access to care for those without a routine source of care and provide better continuity for these high-risk youth.

Adolescent↗
PubMed2000

Effect of age and testosterone on the vasopressin and aquaporin responses to dehydration in Fischer 344/Brown-Norway F1 rats.

To determine if the aging-associated decline in testosterone results in attenuated vasopressin (VP) responses to dehydration, testosterone implants were given to aged male Fischer 344Brown-Norway F1(F344BNF1) rats. Water deprivation caused comparable dehydration, increased plasma VP (pVP), and decreased posterior pituitary (PP) VP content in 4-, 15-, and 28-month-old rats. Dehydration increased VP mRNA content of supraoptic nuclei only at 4 months, whereas VP mRNA length was increased at both 4 and 15 months of age. The elevated pVP in the water-deprived aged rats indicates that even without an increase in VP mRNA content, PP VP storage was adequate to maintain elevated pVP. Dehydration increased aquaporin-2 content at 4, but not at 15 or 28 months of age, suggesting decreased renal responsiveness to VP. Testosterone replacement did not produce dehydration-induced increases in VP mRNA or aquaporin-2. Therefore, testosterone deficiency does not result in altered VP responses to dehydration in aged F344BNF1 rats.

Aging↗
PubMed2000

Angiotensin II increases vasopressin-stimulated facilitated urea permeability in rat terminal IMCDs.

Angiotensin II receptors are present along the rat inner medullary collecting duct (IMCD), although their physiological role is unknown. Because urea is one of the major solutes transported across the terminal IMCD, we measured angiotensin II's effect on urea permeability. In the perfused rat terminal IMCD, angiotensin II had no effect on basal urea permeability but significantly increased vasopressin-stimulated urea permeability by 55%. Angiotensin II, both without and with vasopressin, also increased the amount of (32)P incorporated into urea transporter (UT)-A1 in inner medullary tissue exposed to these hormones ex vivo. Because angiotensin II activates protein kinase C, we tested the effect of staurosporine (SSP). In the absence of angiotensin II, SSP had no effect on vasopressin-stimulated urea permeability in the perfused terminal IMCD. However, SSP completely and reversibly blocked the angiotensin II-mediated increase in vasopressin-stimulated urea permeability. SSP and chelerythrine reduced the angiotensin II-stimulated (32)P incorporation into UT-A1 in inner medullary tissue exposed ex vivo. We conclude that angiotensin II increases vasopressin-stimulated facilitated urea permeability and (32)P incorporation into the 97- and 117-kDa UT-A1 proteins via a protein kinase C-mediated signaling pathway. These data suggest that angiotensin II augments vasopressin-stimulated facilitated urea transport in the rat terminal IMCD and may play a physiological role in the urinary concentrating mechanism by augmenting the maximal response to vasopressin.

Angiotensin II↗
PubMed1999

Heat shock proteins 70 and 90 increase calcineurin activity in vitro through calmodulin-dependent and independent mechanisms.

We have shown that heat shock proteins (HSPs) associated with steroid receptor complexes are involved in the activation of calcineurin by aldosterone and dexamethasone. To determine whether HSPs directly interact with calcineurin, we measured the effect of HSPs 90, 70 and 56 on calcineurin activity in a cell-free, in vitro system using a calcineurin-specific substrate. HSP-90 (75 or 100 nM) significantly increased calcineurin V(max) in the presence of calmodulin, while maximal stimulation by HSP-70 occurred at 50 nM. Bovine serum albumin (BSA) and actin did not change basal calcineurin activity indicating that HSP-90 and HSP-70 specifically activate calcineurin. Neither HSP-70, HSP-56, nor ATP augmented HSP-90-induced activation of calcineurin. In the absence of calmodulin, HSP-90 restored calcineurin activity to basal levels while higher concentrations (333 and 500 nM) increased calcineurin activity. In contrast, HSP-70 failed to activate calcineurin activity in the absence of calmodulin. Immunoprecipitation of HSP-90 from in vitro mixtures as well as protein extracts from LLCPK-1 cells demonstrates that calcineurin co-precipitates with HSP-90. In summary: (1) HSP-90 and 70 stimulate calcineurin V(max) in vitro; (2) non-specific protein interactions do not activate calcineurin activity; (3) HSP-70 and HSP-56 do not enhance HSP-90-induced activation of calcineurin; (4) HSP-70 and HSP-90 activate calcineurin via a calmodulin-dependent and independent pathways; (5) Calcineurin co-precipitates with HSP-90 from LLCPK-1 cells as well as cell-free in vitro preparations.

Adenosine Triphosphate↗
PubMed1999

Access to medical care for adolescents: results from the 1997 Commonwealth Fund Survey of the Health of Adolescent Girls.

PURPOSE: This study examined the factors associated with access to care among adolescents, including gender, insurance coverage, and having a regular source of health care. METHODS: Analyses were done on the 1997 Commonwealth Fund Survey of the Health of Adolescent Girls, a nationally representative sample of in-school adolescents in 5th through 12th grade. Access to health care, missing needed care, and whether the adolescent had private time with their provider were assessed. Cochran-Mantel-Haenszel chi-square statistics were computed using SUDAAN. RESULTS: Nearly a third of the 6748 adolescents surveyed had missed needed care. The most common reason for missing care was not wanting a parent to know (35%). Girls were more likely than boys to miss care (29% vs. 24%). Most adolescents reported using a source of primary health care (92%); girls were more likely than boys to use a physician's office rather than another site (65% vs. 60%). Eleven percent of adolescents reported having no health insurance. Uninsured adolescents were more likely to have missed needed care (46% vs. 25%) [corrected]. CONCLUSIONS: Certain groups of adolescents have less access to health care. Girls have more emotional barriers, such as not wanting parents to know about care, and embarrassment. Adolescents without health insurance are at high risk for missing care because of financial strain. States, insurers, and advocates can influence policies around confidentiality and insurance coverage to address these issues.

Adolescent↗
PubMed1999

Adolescent girls' and boys' preferences for provider gender and confidentiality in their health care.

PURPOSE: To assess the influence of demographic variables and health risk status on adolescents' preferences and actual receipt of services regarding provider gender, sharing a physician with parents, and private examinations. METHODS: Data from students participating in the Commonwealth Fund 1997 Survey of the Health of Adolescent Girls were analyzed. The weighted sample included 6748 students from grades 5-12. The influence of demographic variables and health risk status on preferences regarding physician gender, sharing a physician with parents, and parental presence during examinations and on actual physician gender, sharing a physician with parents, and receipt of confidential care was assessed for the 5067 students who indicated that they had a health check-up or physical examination within the past 2 years. Associations were examined using SAS to determine preliminary estimates of significance and correlation coefficients, and SUDAAN to generate proportions and Cochran Mantel-Haenszel Chi-squared values. A multiple logistic regression procedure in SUDAAN was used to assess interaction among demographic variables. RESULTS: Gender, race/ethnicity, grade level, and risk status were associated with preferences regarding provider gender and sharing a physician with parents. 50% of girls preferred a female provider; 48% had no preference. 23% of boys preferred a male provider; 65% had no preference. Most adolescents had no preference regarding whether they shared a physician with parents. Gender, race/ethnicity, grade level, and risk status were associated with preference regarding parental presence during examinations. Most younger girls preferred to have a parent present; most younger boys had no preference. Most older girls and boys preferred private examinations. For actual care situation, most adolescents were cared for by male health providers and did not share a physician with parents. 57% of girls and 66% of boys spoke privately with their health provider. Girls who had a female physician were more likely to have private time than were girls receiving care from a male physician. Gender, grade level, and risk status were associated with having private time with a physician. CONCLUSIONS: Gender was a significant variable in adolescents' preferences regarding health care. Preferences were also influenced by race/ethnicity, grade level, and risk status. A substantial proportion of adolescents, including those involved in health risk activities, report not having private time with their health provider.

Adolescent↗
PubMed1999

Antibiotic susceptibilities of group C and group G streptococci isolated from patients with invasive infections: evidence of vancomycin tolerance among group G serotypes.

A retrospective review of medical records for 32 patients with invasive group C streptococcus (GCS) or group G streptococcus (GGS) infections was performed. MICs and minimum bactericidal concentrations (MBCs) of penicillin, erythromycin, and vancomycin for all isolates were obtained. Tolerance of vancomycin, defined as an MBC 32 or more times higher than the MIC, was exhibited by 18 GGS isolates (54%). The identification of tolerance in clinical isolates of GGS and GCS may have clinical implications in treating these seriously ill patients.

Adult↗
PubMed1999

Vasoconstrictors and nitrovasodilators reciprocally regulate the Na+-K+-2Cl- cotransporter in rat aorta.

Little is known about the function and regulation of the Na+-K+-2Cl- cotransporter NKCC1 in vascular smooth muscle. The activity of NKCC1 was measured as the bumetanide-sensitive efflux of 86Rb+ from intact smooth muscle of the rat aorta. Hypertonic shrinkage (440 mosmol/kgH2O) rapidly doubled cotransporter activity, consistent with its volume-regulatory function. NKCC1 was also acutely activated by the vasoconstrictors ANG II (52%), phenylephrine (50%), endothelin (53%), and 30 mM KCl (54%). Both nitric oxide and nitroprusside inhibited basal NKCC1 activity (39 and 34%, respectively), and nitroprusside completely reversed the stimulation by phenylephrine. The phosphorylation of NKCC1 was increased by hypertonic shrinkage, phenylephrine, and KCl and was reduced by nitroprusside. The inhibition of NKCC1 significantly reduced the contraction of rat aorta induced by phenylephrine (63% at 10 nM, 26% at 30 nM) but not by KCl. We conclude that the Na+-K+-2Cl- cotransporter in vascular smooth muscle is reciprocally regulated by vasoconstrictors and nitrovasodilators and contributes to smooth muscle contraction, indicating that alterations in NKCC1 could influence vascular smooth muscle tone in vivo.

Angiotensin II↗
PubMed1999

JNK is a volume-sensitive kinase that phosphorylates the Na-K-2Cl cotransporter in vitro.

Cell shrinkage phosphorylates and activates the Na-K-2Cl cotransporter (NKCC1), indicating the presence of a volume-sensitive protein kinase. To identify this kinase, extracts of normal and shrunken aortic endothelial cells were screened for phosphorylation of NKCC1 fusion proteins in an in-the-gel kinase assay. Hypertonic shrinkage activated a 46-kDa kinase that phosphorylated an NH2-terminal fusion protein, with weaker phosphorylation of a COOH-terminal fusion protein. This cytosolic kinase was activated by both hypertonic and isosmotic shrinkage, indicating regulation by cell volume rather than osmolarity. Subsequent studies identified this kinase as c-Jun NH2-terminal kinase (JNK). Immunoblotting revealed increased JNK activity in shrunken cells; there was volume-sensitive phosphorylation of NH2-terminal c-Jun fusion protein; immunoprecipitation of JNK from shrunken cells but not normal cells phosphorylated NKCC1 in gel kinase assays; and treatment of cells with tumor necrosis factor, a known activator of JNK, mimicked the effect of hypertonicity. We conclude that JNK is a volume-sensitive kinase in endothelial cells that phosphorylates NKCC1 in vitro. This is the first demonstration of a volume-sensitive protein kinase capable of phosphorylating a volume-regulatory transporter.

Animals↗
PubMed1999

Long-term cognitive effects of Lyme disease in children.

Most studies of adults infected with Lyme disease (LD) have found adverse cognitive effects from the disease. In contrast, the only controlled study investigating cognitive effects of LD in a pediatric population found no effects after a 2-year follow-up. However, it was questioned whether the negative effects might take longer than 2 years to emerge. Therefore, this investigation reports a 4-year follow-up of the original sample. Twenty-five children with strictly defined LD were compared with 17 sibling control children. A neuropsychological battery was utilized, including assessment of the cognitive areas of IQ, information processing speed, fine-motor dexterity, novel problem solving and executive functioning, short-term and intermediate memory, and acquisition of new learning. In addition, parents' subjective ratings were obtained on the disease's impact on their child's participation in everyday activities. No between-group differences were found for 17 of the 18 neuropsychological test measures, nor were there differences in parents' subjective ratings. Therefore, in contrast with studies of adults with LD, the results of long-term follow-up of the pediatric population continue to strongly support the finding that children treated appropriately for LD have an excellent prognosis for normal cognitive functioning.

Adolescent↗