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Biomedical subjects

S Kaplan

Publications and source records attributed to S Kaplan.

At least 19 recordsLinked to original sources
PubMed2006

Genome analyses of three strains of Rhodobacter sphaeroides: evidence of rapid evolution of chromosome II.

Three strains of Rhodobacter sphaeroides of diverse origin have been under investigation in our laboratory for their genome complexities, including the presence of multiple chromosomes and the distribution of essential genes within their genomes. The genome of R. sphaeroides 2.4.1 has been completely sequenced and fully annotated, and now two additional strains (ATCC 17019 and ATCC 17025) of R. sphaeroides have been sequenced. Thus, genome comparisons have become a useful approach in determining the evolutionary relationships among different strains of R. sphaeroides. In this study, the concatenated chromosomal sequences from the three strains of R. sphaeroides were aligned, using Mauve, to examine the extent of shared DNA regions and the degree of relatedness among their chromosome-specific DNA sequences. In addition, the exact intra- and interchromosomal DNA duplications were analyzed using Mummer. Genome analyses employing these two independent approaches revealed that strain ATCC 17025 diverged considerably from the other two strains, 2.4.1 and ATCC 17029, and that the two latter strains are more closely related to one another. Results further demonstrated that chromosome II (CII)-specific DNA sequences of R. sphaeroides have rapidly evolved, while CI-specific DNA sequences have remained highly conserved. Aside from the size variation of CII of R. sphaeroides, variation in sequence lengths of the CII-shared DNA regions and their high sequence divergence among strains of R. sphaeroides suggest the involvement of CII in the evolution of strain-specific genomic rearrangements, perhaps requiring strains to adapt in specialized niches.

Chromosomes, Bacterial↗
PubMed2006

Methylene blue decreases ischemia-reperfusion (I/R)-induced spinal cord injury: an in vivo study in an I/R rabbit model.

OBJECTIVES: To evaluate the effects of intravenous methylene blue (MB) administration on ischemia-reperfusion (I/R) injury of the spinal cord (SC). METHODS: 16 rabbits were randomly assigned either to group M (n = 8; receiving MB, intervention group) or group C (n = 8; control group) and underwent a 30-min period of SC ischemia by clamping the abdominal aorta between the left renal artery and the aortic bifurcation. 15 min before clamping, rabbits received either intravenous MB (10 mg/kg; group M) or normal saline (group C). The two groups were compared 24 h postoperatively both histologically and for neurological function, using a Tarlov score. Measurements to determine levels of malondialdehyde (MDA) and glutathione (GSH) in the SC tissue were also performed. RESULTS: Neurological impairment and spinal tissue MDA levels were significantly lower in animals treated with MB (p < 0.001). In contrast, spinal GSH levels were significantly higher in group M (p < 0.001). Histological examination revealed that the integrity of the SC was better preserved in the MB group, whereas cords from the control group exhibited evidence of acute neuronal injury. CONCLUSIONS: The prophylactic use of MB reduces neurological injury and improves clinical outcomes in the rabbit SC I/R model. These effects are probably mediated by the drug's antioxidant properties.

Animals↗
PubMed2006

Public, patient, and professional attitudes towards the diagnosis and treatment of enlarged prostate: A landmark national US survey.

This US national survey evaluated beliefs and attitudes towards the enlarged prostate (EP) and its treatment among the men of a national sample aged > or =50 years in the US (400 with and 700 without EP), and a national sample of 100 primary care doctors and 100 urologists. The principal risk of EP was considered to be acute urinary retention among the majority of physicians, while the majority of patients believed it to be prostate cancer. In contrast to physicians' beliefs, the majority of patients with moderate-to-severe symptoms are more concerned with long-term effects of EP than acute symptoms. Furthermore, they are willing to wait up to 3 months for symptom relief if treatment of the underlying condition is achieved. Doctors and patients agree that most patients want to avoid surgery but only 18% of surgery patients were told about drugs that could reduce the risk of surgery. These findings demonstrate significant differences between the beliefs and attitudes of patients and physicians towards EP.

Aged↗
PubMed2006

Advocacy skills training for young adult cancer survivors: the Young Adult Survivors Conference at Camp Māk-a-Dream.

GOALS OF THE WORK: This manuscript reports on the design, implementation, and evaluation of the Young Adult Survivor Conference (YASC)-a 4-day retreat designed to provide an educational and support experience for cancer survivors diagnosed as children, adolescents, and young adults. The goals of the program were to address issues of survivorship, provide cancer education and tools for self-advocacy, and build bridges of support among young adult cancer survivors who may be experiencing similar journeys through life. THE PROGRAM: YASC was designed to offer advocacy skills specific to participants' needs. Workshops focused on understanding late effects, mentoring and communication, tips for starting peer support programs and networks, and opportunities for offering public testimony and involvement in public policy. EVALUATION: Program evaluation indicated that participants achieved personal goals and expectations for having fun, meeting other survivors, understanding more about their cancer and potential late effects, and learning about how to tell their story so that it will help others. CONCLUSIONS: Involvement with peers who have shared a similar experience provided participants an opportunity to address areas of concern such as coping with uncertainty, dependency vs autonomy, social exclusion, body image, intimacy, sexuality and fertility, and career options. Participation in programs such as the YASC offers young survivors opportunities for life experiences that may promote successful achievement of age-appropriate developmental tasks.

Adaptation, Psychological↗
PubMed2006

A model of unilateral frontal focal cerebral venous occlusion in the rat.

OBJECTIVE: The aim of this experimental study was to create a new focal venous infarction model in rats. METHOD: 20-male Sprague-Dawley rats were used in this experiment. Unilateral frontal strip craniectomy was done in front of the coronal suture. Frontal veins were observed by using the operative microscope. In this study we used the bipolar coagulation method over the transparent dura mater for occlusion of the bridging veins for venous infarction. Specimens were evaluated by histopathological techniques. RESULTS: Unilateral frontal hemispheric swelling, midline shift, brain edema, subcortical petechial hemorrhage, hemorrhagic infarction and necrosis were the histopathological findings on microscopic examination. CONCLUSION: Our results revealed that the bipolar coagulation method over the transparent dura mater for occlusion of the unilateral frontal cortical veins for venous infarction might be a new experimental model in the evaluation of brain damage after disturbance to the venous circulation.

Animals↗
PubMed2006

Effects of constant lightness, darkness and parachlorophenylalanine treatment on tail regeneration in the lizard Ophisops elegans macrodactylus: macroscopic, biochemical and histological changes.

A better understanding of regenerative growth is very important for the development of new potential strategies. Recently, the pineal secretory product melatonin was shown to stimulate the regeneration process. In this study, we carried out an experimental investigation of tail regeneration in young adult lizards, Ophisops elegans macrodactylus Berthold, 1842, addressing the role of melatonin on the regeneration process. Lizards were divided into three groups: constant light-exposed control group (n = 13), constant dark-exposed group (n = 15) and parachlorophenylalanine (p-CPA) treatment group exposed to constant light (n = 15). Using a tail autotomy procedure, the effects of p-CPA treatment on connective tissue together with neural tissue and vascular tissue in regenerating tail in lizards were investigated. p-CPA (400 microg/kg body mass) was injected from day 0 to 30 days after autotomy. p-CPA treatment produced a significant increase in the length of the regenerated tail compared with light-exposed control and dark-exposed lizards. Total collagen content was found to be higher in p-CPA-treated animals in comparison with other groups. Histologically, a higher percentage of connective tissue and vascular tissue and a lower percentage of neural tissue were found in the regenerated tails of the p-CPA-treated lizards. Importantly, the percentage of neural tissue in lizards in the dark-exposed animals was higher than that in animals of both light-exposed and p-CPA treatment groups. Thus, it is clear that p-CPA has a stimulatory influence on fibroblast collagen production and vascularization of the regenerated tail in the lizards. Furthermore, it seems that the neural regeneration process was markedly enhanced in lizards exposed to continuous darkness. Based on the results of our study, it is suggested that melatonin may be an active factor that speeds up the rate of tail regeneration in lacertilians.

Animals↗
PubMed2005

Interacting regulatory networks in the facultative photosynthetic bacterium, Rhodobacter sphaeroides 2.4.1.

Regulation of photosynthetic membrane synthesis in Rhodobacter sphaeroides 2.4.1 is dependent on the interactions of numerous regulatory elements, with two of the most important being the cbb(3) terminal oxidase and the PrrBAC two-component regulatory system. Here, we reveal that the cbb(3) terminal oxidase possesses extensive, additional regulatory activities under anaerobic conditions, and that the PrrBAC system is further involved in the regulation of the expression of more than 20% of the R. sphaeroides genome under anaerobic conditions, extending well beyond functions related to redox gene expression.

Bacterial Proteins↗
PubMed2005

The effects of venous ischaemia on the subependymal and choroid plexus morphology in rat.

Morphological changes of ependyma, subependyma and choroids plexus regions were evaluated after experimental anastomotic venous occlusion in twenty male Sprague-Dawley rats. In this model, small burr holes were made over the anterior and posterior anastomotic veins and after precisely locating these vessels, bipolar coagulation and microscissors were used to perform permanent occlusion. Three days later, rats were sacrificed by perfusion and fixation and specimens were evaluated by histopathological techniques. Morphological changes of ependymal, subependymal and choroids plexus cells were evaluated in operated and intact hemispheres and revealed cell proliferation in the subventricular zone adjacent to the territory of venous occlusion in the operated hemisphere as well as midline shift, brain oedema, subcortical petechial haemorrhage, brain infarction and hemispheric swelling. In conclusion, following anterior (the vein of Throlard) and posterior (the vein of Labbé) anastomotic vein occlusion, cell proliferation can be seen in the choroids plexus, ependymal and subependymal regions in rats. We conclude that these morphological changes might be part of a self-repairing mechanism in the brain.

Animals↗
PubMed2004

No-touch technique for autologous fat harvesting.

A new technique for autologous fat harvesting is presented. It is termed the "no-touch" technique because the concentrated fat graft is obtained with no handling of fatty tissue. With the no-touch technique, fat aspiration is performed under tourniquet. There is no need for any mechanical manipulations such as centrifugation, washing, whisking, filtering, or straining. The medial aspect of the knee is used as the donor area. Fat is aspirated through a disposable 10-ml syringe and a 14-gauge microcannula, which consists of a curved, semiblunted tip such as that of the Tuohy needle. What remains in the syringe is the concentrated fat without blood, serum, or lidocaine. The authors report their experience with 30 patients.

Adipose Tissue↗
PubMed2004

Oxygen intervention in the regulation of gene expression: the photosynthetic bacterial paradigm.

The means by which oxygen intervenes in gene expression has been examined in considerable detail in the metabolically versatile bacterium Rhodobacter sphaeroides. Three regulatory systems are now known in this organism, which are used singly and in combination to modulate genes in response to changing oxygen availability. The outcome of these regulatory events is that the molecular machinery is present for the cell to obtain energy by means that are best suited to prevailing conditions, while at the same time maintaining cellular redox balance. Here, we explore the dangers associated with molecular oxygen relative to the various metabolisms used by R. sphaeroides, and then present the most recent findings regarding the features and operation of each of the three regulatory systems which collectively mediate oxygen control in this organism.

Cell Membrane↗
PubMed2004

Can initial tacrolimus trough levels be predicted from clinical variables?

In eligible patients, cardiac transplantation has become the definitive treatment for end-stage heart failure. The initial posttransplantation course is marked by many potential difficulties, including renal insufficiency, hemodynamic instability, and perioperative bleeding. It is important to prevent early rejection; calcineurin inhibitors, such as tacrolimus or cyclosporine, are integral parts of such management. However, these drugs are associated with renal toxicity in some patients. Previous work suggests that limiting the increase in tacrolimus levels is associated with less renal insufficiency. The hypothesis of the current study was that a combination of clinical or laboratory variables could identify patients at risk for rapid changes in tacrolimus target levels. No single variable was strongly associated with high resultant trough levels following a standard 1-mg oral "test dose" of tacrolimus. However, the combination of 2 indices of liver metabolism (alanine aminotransferase and total bilirubin) along with serum creatinine did identify patients who tended toward elevated levels of tacrolimus (> or =4.5 ng/dL). Other variables, such as demographics, and even functional variables, such as right ventricular function by echocardiography, did not enhance the predictive value of this simple scoring system.

Adult↗
PubMed2004

Refractory humoral cardiac allograft rejection successfully treated with a single dose of rituximab.

Despite improvements in immunosuppression over the last two decades, the risk of allograft rejection is still high in the early postoperative period. Cellular rejection accounts for the majority of these episodes. However, humoral rejection is a distinct phenomenon that carries a high rate of graft loss and mortality. The currently available treatments for this serious clinical problem include anti-lymphocyte antibodies, immune globulin infusions, as well as plasmapheresis, all of which have limitations. We describe a case of refractory humoral cardiac rejection successfully treated with a single dose of rituximab (375 mg/m2). No further episodes occurred with 2 years of follow-up.

Adult↗
PubMed2004

Efficacy and safety of atomoxetine in childhood attention-deficit/hyperactivity disorder with comorbid oppositional defiant disorder.

OBJECTIVE: To compare the safety and efficacy of atomoxetine, a selective inhibitor of the norepinephrine transporter, versus placebo in Attention-Deficit/Hyperactivity Disorder (ADHD) patients with comorbid Oppositional Defiant Disorder (ODD). METHODS: A subset analysis of 98 children from two identical, multi-site, double-blind, randomized, placebo-controlled trials involving 9 weeks of treatment with atomoxetine or placebo was conducted. Patients met DSM-IV ADHD criteria. ODD was diagnosed with the Diagnostic Interview for Children and Adolescents-IV (DICA-IV; Reich, Weiner, and Herjanic, 1997). ADHD severity was assessed with the ADHD Rating Scale-IV-Parent Version: Investigator Administered and Scored (ADHD-RS-IV-Parent:lnv; DuPaul, Power, Anastopoulos, and Reid, 1998); the short version of the Conners' Parent Rating Scales-Revised (CPRS-R:S; Conners, 2000); and the Clinical Global Impressions of ADHD Severity (CGI-ADHD-S; Guy, 1976). Clinical response was defined as a > or = 25% reduction in ADHD-RS-IV-Parent:lnv total score. RESULTS: ADHD-RS-IV-Parent:lnv, CGI-ADHD-S, and three CPRS-R:S subscale scores improved markedly with atomoxetine treatment. However, a decrease in the CPRS-R:S Oppositional subscore for atomoxetine-treated patients was not significantly greater than scores for placebo-treated patients. Clinical response rates were 65.4% in the atomoxetine group, and 36.4% in the placebo group (p = .007). CONCLUSION: Atomoxetine was effective for the treatment of ADHD in patients with comorbid ODD. It did not significantly reduce the severity of ODD symptoms, and was well tolerated by the patients.

Adolescent↗
PubMed2002

Therapeutic effects of intracarotid infusion of spermine/nitric oxide complex on cerebral vasospasm.

BACKGROUND: Vasospasm is one of the underlying causes of morbidity and mortality in subarachnoid haemorrhage (SAH). The therapeutic effects of intracarotid infusion of spermine/nitric oxide complex (SPER/NO) on cerebral vasospasm in an experimental model of SAH were investigated. METHOD: Twenty-four adult male New Zealand white rabbits (2.6-3.4 kg in weight) were randomly divided into four groups (n=6), as follows: (I) control group (without SAH and drug), (II) SAH alone group (with SAH, without drug), (III) SAH placebo group (with SAH and saline), and (IV) SAH-SPER/NO group (with SAH and SPER/NO). The fresh autologous non-heparinized blood was injected into the cisterna magna to induce a SAH, after 24 hour SAH, the substance (saline or SPER/NO) was delivered to animals. All rabbits were scarified at 48-hours of induced SAH. The basilar artery with surrounding tissue was removed from the cranium and processed for paraffin embedding. Histopathological and stereological examinations of the basilar artery were done. FINDINGS: In the SPER/NO treated group of rabbits, the histopathological changes were less severe than in the SAH-alone and SAH-placebo groups. Regarding the intracarotid pressure, there was a statistically significant difference between SAH-alone and SAH-SPER/NO groups and also between SAH-SPER/NO and control groups (p<0.05). The mean cross sectional area of basilar arteries was 0.26 mm(2) in the control, whereas in SAH alone, placebo and SAH-SPER/NO groups were 0.13, 0.15 and 0.20 mm(2), respectively. INTERPRETATION: It is well known that NO is a critical substance involved in cerebral vascular dynamics. Present results indicate that treatment of vasospasm with SPER/NO in SAH may be promising. However, further studies should be done on this substance to clarify its effect on vasospasm before using the drug in clinical situations.

Animals↗
PubMed2002

Depression: reduced number of granule cells in the hippocampus of female, but not male, rats due to prenatal restraint stress.

It has been hypothesized that decreased neurogenesis in the dentate gyrus may be involved in mediating depressive disorders, which are 1.5-3 times more frequent in women than in men. Additionally, prenatal stress may increase the risk of developing depression in adulthood. However, the interrelations between prenatal stress and the development of depression in adulthood, preferentially in females, are not understood. Here, we subjected pregnant rats to a single 20-min period of restraint stress on day 18 after mating. When the offspring were 75 days of age, the numbers of granule cells and pyramidal cells (area CA1-3) in the hippocampus were analyzed with the optical fractionator. The Cavalieri's principle was applied to analyze the volumes of both granule cell layer and pyramidal cell layer in the hippocampus. Prenatally stressed females, but not males, had reduced numbers of hippocampal granule cells compared to their non-prenatally stressed counterparts. This is the first report of a sex-specific difference concerning the reduction of the number of hippocampal granule cells due to prenatal stress. In humans, prenatal stress may induce cell loss in the granule cells of the hippocampus preferentially in females compared to males, and this may be a sex-specific predisposing factor for the development of depression in adulthood.

Animals↗
PubMed2002

Mg++SO4 treatment improves the hemodynamics following the acute myocardial ischemia and reperfusion.

BACKGROUND: The effect of Mg++SO4 on myocardial hemodynamics was investigated in this study. METHODS: Twelve dogs were entered in this research. Six dogs received Mg++SO4 and the remaining dogs were considered as controls. The amount of Mg++SO4 that was administered to the animals was 0.15 mmol/kg/hr each. The left anterior descending artery was occluded for a period of 1 hour and the drug was administered during reperfusion. RESULTS: Two hours after reperfusion, cardiac output was 1275+/-50 ml/min in the control group and 1475+/-25 ml/min in the Mg++SO4 group (p<0.05), pulmonary capillary wedge pressure was 18+/-3 mmHg in the control group and 12+/-2 mmHg in the Mg++SO4 group. CONCLUSIONS: In this study it was shown that Mg++SO4 usage after 1 hour arterial occlusion and 2 hours reperfusion protects the heart from the adverse effects of ischemia/reperfusion and had a better central hemodynamics.

Animals↗
PubMed2002

Protein C, S and antithrombin III levels in patients with acute mechanical valve thrombosis.

BACKGROUND: Mechanical prosthetic heart valve thrombosis is a serious complication with an incidence of 1-6%. The reduction in active vitamin-K dependent protein C and S levels caused by warfarin treatment also results in a prothrombotic state. This study was conducted to investigate the connection between protein C (PC), protein S (PS), antithrombin III (ATIII) deficiency and prosthetic mechanical valve thrombosis. METHODS: Twenty-nine of the 283 patients who underwent valve replacement with St. Jude medical prosthesis had mechanical valve thrombosis (group 2). The rest were considered as group 1. Twelve of the 29 patients (41.4%) had isolated aortic valve replacement, 12 had isolated mitral valve replacement (41.4%) and 5 patients had double valve replacement (17.2%). Most of the patients had rheumatic valve disease at their 1st operation. The mean time of occurrence for mechanical valve occlusion was 4.1+/-1.0 years following surgery. RESULTS: The values of PC, PS and ATIII were obtained when the mechanical valves stuck or at routine follow-up. PC, PS and ATIII levels were significantly lower in the mechanical valve thrombosis group. PC levels were 75.4+/-37.6% and 49.9+/-32.2% in group 1 and 2, respectively (p=0.001). PC, PS and ATIII values were mostly lower in the 2nd group but this difference only became significant after at least 2 years of warfarin usage. CONCLUSIONS: Natural anticoagulant levels can be low during the use of warfarin. In which case the dose can be increased in order to hold the international normalized ratio (INR) at 3-3.5. However, more frequent follow-up is required and patients should be investigated for hypercoagulation states or deficiency in anticoagulant proteins. Patients referred to hospital with any mechanical valve thrombosis or recurrent thromboembolism should be evaluated for hypercoagulant proteins.

Adult↗