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Biomedical subjects

J Katz

Publications and source records attributed to J Katz.

At least 235 records · Page 13Linked to original sources
PubMed1996

Recurrent aphthous stomatitis and thiamine deficiency.

Recurrent aphthous stomatitis is a disease of unknown cause. To examine whether thiamine (vitamin B1) deficiency is associated with recurrent aphthous stomatitis, we studied vitamin B1 levels in 70 patients with recurrent aphthous stomatitis and in 50 members of a control group. The vitamin B1 level was determined as thiamine pyrophosphate effect on transketolase activity in red blood cell lysates. Low levels of vitamin B1 were detected in 49 patients but in only two members of the control group (p < 0.0001). These low levels were not associated with patient age, sex, or underlying disease causing recurrent aphthous stomatitis. Our finding suggests an association between thiamine deficiency and recurrent aphthous stomatitis.

Adolescent↗
PubMed1996

Chronic low intakes of vitamin A-rich foods in households with xerophthalmic children: a case-control study in Nepal.

Dietary patterns in 81 rural Nepali households with a 1-6-y-old child with a history of xerophthalmia were compared with dietary patterns of 81 households with an age-matched nonxerophthalmic control subject. Weekly food-frequency questionnaires were collected from case and control "focus" children, a younger sibling (if present), and the household 1-2 y after recruitment and treatment of cases. Control households and children were more likely than case households and children to consume vitamin A-rich foods during the monsoon (July-September) and major rice harvesting (October-December) seasons. Cases were less likely to consume preformed vitamin A-rich foods throughout the year [odds ratio (OR) = 1.2-4.5] with the strongest differences observed from October to December (OR = 2.0-4.2). Dietary risks were generally shared by younger siblings of cases, suggesting that infrequent intake of beta-carotene and preformed vitamin-A rich foods begins early in life and clusters among siblings within households, a pattern that is consistent with their higher risk of xerophthalmia and mortality. In developing countries where vitamin A deficiency is endemic, dietary counseling for children with xerophthalmia should be extended to their younger siblings. Moreover, dietary intake of preformed vitamin A may be as, or more, important as carotenoid-containing food consumption in protecting children and other members of households from vitamin A deficiency.

Carotenoids↗
PubMed1996

Effects of preemptive or postinjury intrathecal local anesthesia on persistent nociceptive responses in rats. Confounding influences of peripheral inflammation and the general anesthetic regimen.

BACKGROUND: Although experimental evidence indicates that preemptive intrathecal treatment with local anesthetics reduces postinjury neuronal hyperexcitability, clinical evidence indicates that preemptive treatments do not consistently reduce postoperative pain. The current study used experimental models of postinjury nociception, in which rats received subcutaneous or intraarticular injections of the irritant formalin, to evaluate the effects of peripheral inflammation, or the use of agents supplemental to anesthesia, as possible confounding influences on the effectiveness of preinjury and postinjury intrathecal local anesthetic treatments. METHODS: In experiment 1, lumbar intrathecal lidocaine (30 microliters, 2%), given either 5 min before or 5 min after hind paw injection of 50 microliters of varying concentrations of formalin, was compared with intrathecal cerebrospinal fluid, for their effects on nociceptive responses in the late phase of the formalin test. Furthermore, the effect of hind paw injection of 50 microliters of 2.5, 3.75, or 5.0% formalin on peripheral inflammation was assessed by measuring plasma extravasation in the hind paws of rats given Evans Blue dye (50 mg/kg, intravenous). In experiment 2, rats received a deep tissue injury (100 microliters of 5.0% formalin into the knee joint) while under halothane anesthesia. In addition to halothane (3-4%), rats received either saline, pentobarbital (13 mg/kg, intraperitoneal), or pentobarbital + morphine (0.5 mg/kg, intravenous), with or without preinjury or postinjury spinal anesthesia using intrathecal bupivacaine (30 microliters, 0.75%), to assess the effects of supplemental treatments on the preemptive effects of intrathecal bupivacaine. RESULTS: Lumbar intrathecal lidocaine pretreatment, but not posttreatment, significantly reduced late phase nociceptive responses to hind paw injections of 2.5% formalin. The preemptive effects of lidocaine were overridden in rats that received hind paw injections of 3.75 and 5.0% formalin. Hind paw injection of 50 microliters of 3.75 or 5.0%, but not 2.5% formalin produced an increase in plasma extravasation. Either pentobarbital or pentobarbital + morphine treatment, or a pentobarbital + morphine treatment and postinjury treatment with intrathecal bupivacaine failed to produce a significant reduction in the nociceptive response to the deep tissue injury. However, rats that received pentobarbital + morphine treatments and intrathecal bupivacaine before the injury had significantly reduced nociceptive responses to deep tissue injury when compared to the saline control group, but not to the group that received pentobarbital + morphine treatment and postinjury treatment with bupivacaine. CONCLUSIONS: The current results attest to the important effects of ongoing inputs from inflamed tissue, and the use of supplemental treatments, as important confounding factors that may influence the effectiveness of preemptive spinal anesthesia for postoperative pain.

Analgesia↗
PubMed1996

Acute pain after thoracic surgery predicts long-term post-thoracotomy pain.

OBJECTIVE: Long-term pain is a common sequela of thoracotomy, occurring in approximately 50% of patients 2 years after thoracic surgery. Despite this alarming statistic, little is known about the factors responsible for the transition of acute to chronic pain. The aim of the present study is to identify predictors of long-term post-thoracotomy pain. DESIGN: Follow-up was for 1.5 years for patients who had participated in a prospective, randomized, controlled trial of preemptive, multimodal analgesia. SETTING: Subjects were recruited from a tertiary care center. PATIENTS: Thirty patients who had undergone lateral thoracotomy were followed up by telephone, administered a structured interview, and classified according to long-term pain status. MAIN OUTCOME MEASURES: Present pain status was measured by a verbal rating scale (VAS). Measures obtained within the first 48 h after surgery were compared between patients with and without pain 1.5 years later. These include VAS pain scores at rest and after movement, McGill Pain Questionnaire data, patient-controlled morphine consumption (mg), and pain thresholds to pressure applied to a rib contralateral to the thoracotomy incision. RESULTS: Fifty-two percent of patients reported long-term pain. Early postoperative pain was the only factor that significantly predicted long-term pain. Pain intensity 24 h after surgery, at rest, and after movement was significantly greater among patients who developed long-term pain compared with pain-free patients. A significant predictive relationship was also found at 24 and 48 h using the McGill Pain Questionnaire. Cumulative morphine was comparable for the two groups. Pain thresholds to pressure applied to a rib contralateral to the incision did not differ significantly between the groups. CONCLUSION: Aggressive management of early postoperative pain may reduce the likelihood of long-term post-thoracotomy pain.

Acute Disease↗
PubMed1996

Superconducting receiver coils for sodium magnetic resonance imaging.

We present the results from sodium magnetic resonance imaging (MRI) experiments using high-temperature superconducting (HTS) receiver coils. Sodium imaging has been shown to have great potential for the assessment of cell integrity but suffers from a substantially lower signal-to-noise ratio (SNR) than that of a hydrogen imaging. The use of an HTS receiver coil was found to significantly increase the SNR relative to an equivalent copper receiver coil at room temperature. The SNR gains afforded by HTS coils can also be used to decrease the imaging time.

Copper↗
PubMed1996

Host responses induced by co-infection with Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans in a murine model.

In this study, evidence is presented that mixed infection with the periodontal pathogens Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans results in a synergistic effect in their pathogenicity and in their ability to induce humoral and cellular host responses. BALB/c mice were injected subcutaneously on the back with P. gingivalis ATCC 53977, A. actinomycetemocomitans 75 or a mixture of both bacteria. Samples of blood and fluid from abscesses formed at the site of injection (first degree) or distant from the injection site were collected for microbiologic analysis. Serum and spleens were obtained for evaluation of humoral and cellular responses to P. gingivalis and A actinomycetemocomitans. Mice injected with A. actinomycetemcomitans had first-degree lesions only, whereas mice injected with P. gingivalis and A. actinomycetemcomitans had lesions at first- and second-degree sites from which both bacterial species were isolated. A serum anti-P. gingivalis response was induced in P. gingivalis-injected mice, which was higher in mice injected with P. gingivalis and A. actinomycetemcomitans. This pattern was not seen in the anti-A, actinomycetemcomitans response. Lymphoproliferative responses to phytohemagglutinin, Escherichia coli lipopolysaccharide and P. gingivalis of spleen cells from infected mice were decreased, especially following co-infection. Furthermore, co-infection of mice resulted in the greatest decrease in the number of CD5+, especially CD4+ lymphocytes.

Aggregatibacter actinomycetemcomitans↗
PubMed1996

Effect of host responses on the pathogenicity of strains of Porphyromonas gingivalis.

Porphyromonas gingivalis is implicated in the etiology of periodontitis. Strains of P. gingivalis have been classified as invasive or noninvasive based on their ability to form abscesses in a mouse model. The purpose of this study was to investigate the ability of P. gingivalis strains to cause abscesses and periodontal bone loss in an experimental rat model and the effect of serum and salivary responses on the pathogenicity of these strains. Subcutaneous injection of animals with P. gingivalis 33277, A7A1-28, W50 or 381 resulted in abscesses in a higher percentage of mice than rats. P. gingivalis 33277 caused lesions at the site of injection, whereas strains A7A1-28 and W50 induced abscesses at distant sites in both mice and rats. Local lesions were seen in rats injected with strain 381, whereas lesions formed distant from the site of injection in mice. When periodontal bone loss was assessed in the experimental rat model, animals challenged with 33277 had the highest amount of horizontal and vertical bone loss. Rats challenged with strain A7A1-28, W50 or 381 had some or no periodontal bone loss compared with controls. Assessment of antibody responses to P. gingivalis in these animals revealed that rats challenged with 33277 had lower levels of serum immunoglobulin G-(IgG) and especially salivary IgA antibody activity than A7A1-28-challenged rats. Serum IgG and in particular salivary IgA anti-P. gingivalis responses were seen in W50- and 381-challenged rats. These results indicate that the ability of P. gingivalis strains to cause abscesses does not relate directly to their periodontal pathogenicity as assessed by periodontal bone loss in the same animal model. The results further suggest the importance of salivary IgA antibody responses in protection against experimental periodontal bone loss after challenge with P. gingivalis.

Abscess↗
PubMed1996

Prevalence and risk factors for trachoma in Sarlahi district, Nepal.

AIMS: To estimate the prevalence of trachoma in preschool children in Sarlahi district, Nepal, and to identify risk factors for the disease. METHODS: A stratified random sample of 40 wards was selected for participation in a trachoma survey. Within each ward, a systematic 20% sample of children 24-76 months of age was chosen to determine the presence and severity of trachoma using the World Health Organisation grading system. RESULTS: A total of 891 children were selected and 836 (93.8%) were examined for trachoma from December 1990 to March 1991. The prevalence of active trachoma was 23.6% (21.9% follicular and 1.7% intense inflammatory). Cicatricial trachoma was not seen in this age group. The prevalence of trachoma ranged from 0 to 50% across wards with certain communities at much higher risk for trachoma than others. Three year old children had the highest prevalence of follicular (25.5%) and intense inflammatory trachoma (4.3%). Males and females had similar prevalence rates. Wards without any tube wells were at higher risk than those with one or more tube wells. Lower rates of trachoma were seen in families who lived in cement houses, had fewer people per room, more servants, more household goods, animals, and land. Hence, less access to water, crowding and lower socioeconomic status were risk factors for trachoma. CONCLUSIONS: Although follicular trachoma is prevalent, intense inflammatory trachoma is relatively rare and scarring was not observed in this preschool population. Hence, this population may not be at high risk for repeat infections leading to blindness in adulthood.

Child↗
PubMed1996

Glucose production, recycling, and gluconeogenesis in normals and diabetics: a mass isotopomer [U-13C]glucose study.

Eight normal controls and nine non-insulin-dependent diabetes mellitus diabetics were, after an overnight fast, infused for 3 h with [6-3H]- and with [U-13C]glucose with six 13C carbons at rates from 0.03 to 0.15 mg.kg-1.min-1. Plasma glucose and lactate were assayed by gas chromatography-mass spectroscopy. Several parameters of glucose metabolism were calculated from the mass isotopomer distribution. Glucose production (GP) determined with [6-3H]- and [U-13C]glucose agreed closely. GP was 1.9 +/- 0.16 (range 1.3-2.5) mg.kg-1.min-1 in controls and 2.8 +/- 0.29 (1.7-4.5) mg.kg-1.min-1 in diabetics (P < 0.05). The correlation in diabetes between plasma glucose and GP (r = 0.911, P < 0.01) was close. Recycling of carbon (8 vs 7%) dilution by unlabeled carbon (2- vs 2.3-fold), and dilution via the tricarboxylic acid cycle (1.5-fold) were similar in controls and diabetics. Gluconeogenesis was 0.90 +/- 0.08 (0.5-1.3) mg.kg-1.min-1 in controls and 1.30 +/- 0.13 (0.8-1.9) mg.kg-1.min-1 in diabetics (P < 0.05). Gluconeogenesis contributions to GP were 46.6 +/- 4.0% (26-61%) in the controls and 48.8 +/- 5.7% (32-83%) in diabetics. We show that, using [U-13C]glucose infusion of 2-5% of glucose turnover (0.03-0.10 mg.kg-1.min-1), a large number of parameters of glucose metabolism may be determined in humans.

Diabetes Mellitus, Type 2↗
PubMed1996

Blindness and visual impairment in western Bulgaria.

The Sofia Eye Survey was a population-based blindness and visual impairment survey of 6,275 randomly selected men and women from the Sofia district and Sofia city in western Bulgaria. A complete house-to-house census on all adults over age 40 years was performed, and visual acuity performed on 98%. We referred 171 subjects for a complete dilated ophthalmologic examination because the pinhole vision in the better eye was 6/18 or worse. Trained ophthalmologists refracted all referred subjects and then examined them with a slit lamp and ophthalmoscopy to determine the cause of visual loss. The rate of blindness (defined as vision in the better eye worse than 3/60) in this population was 0.49% and the rate of visual impairment (6/18 to 3/60 in the better eye) was 0.83%. The leading cause of both blindness and visual impairment was cataract. These data from the first community-based survey of blindness in Eastern Europe suggest that the rates of blindness and visual impairment are similar to those reported from other developed countries.

Adult↗
PubMed1996

HIV arthritis.

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Adult↗
PubMed1996

Analysis of progressive change in automated visual fields in glaucoma.

PURPOSE: To detect and estimate the rate of progression of visual field loss in subjects with glaucoma who undergo long-term automated perimetric visual field testing. METHODS: Automated visual field data were obtained for subjects with glaucomatous visual field loss and a minimum of seven threshold field tests over at least 4.5 years. Univariate linear regression was performed with respect to mean deviation (MD), corrected pattern standard deviation (CPSD), mean thresholds of clusters corresponding to the Glaucoma Hemifield Test (GHT), and thresholds of 52 individual test locations. Subjects were classified as progressive or stable (unchanged or improved) based on the slope and statistical significance of these parameters. Adjusted P values were used to maintain the overall type 1 error at 5%. RESULTS: One hundred ninety-one subjects with a mean follow-up period of 7.1 years (range, 4.5 to 10.5 years) and a mean number of visual field tests of 9.5 (range, 7 to 16) were included. Twenty-four subjects (12.6%) showed progression in MD (mean slope [95% confidence interval], -1.26 [-1.50, -1.01] dB/year), and 27 (14.1%) showed progression in CPSD (mean slope [95% confidence interval], 0.71 [0.58, 0.84] dB/year). Thirty-five subjects (18.3%) had > or = 1 progressive GHT cluster. The mean slope in progressive clusters ranged from -1.51 [-1.82, -1.20] to -2.84 [-3.39, -2.29] dB/year. Thirty-six subjects (18.8%) had > or = 1 progressive individual test locations. Fifty-two subjects (27.2%) were classified as progressive based on progression of CPSD, > or = 1 cluster and/or > or = 1 point. CONCLUSIONS: Fewer than 1 in 3 subjects progressed by any one of the criteria for progression over an average of 7.1 years. Rates of progression that could be statistically confirmed were in the range of approximately 1 to 5 dB/year, depending on the number of fields, the variability over time, and the parameter assessed (global indices, GHT clusters, or individual points). No correlation between initial visual field status and the rate of progression was found. A minimum of approximately 5 years of follow-up with annual perimetry would be required to detect significant changes in the visual field by linear regression.

Adolescent↗
PubMed1996

Neurotoxic and pharmacologic studies on enantiomers of the N-methylated analog of cathinone (methcathinone): a new drug of abuse.

These studies evaluated neurotoxic and pharmacologic properties of the R(+) and S(-) enantiomers of methcathinone, a psychostimulant drug that has surfaced in the illicit drug market, primarily in the S(-) form. Neurotoxic potential toward brain dopamine (DA) and serotonin (5-HT) neurons was assessed by measuring DA and 5-HT axonal markers and by means of silver degeneration studies; pharmacologic effects were evaluated by measuring locomotor stimulation. Methcathinone produced dose-related neurotoxic and locomotor stimulant effects which were species- and enantiomer-dependent. In mice, although both enantiomers produced toxic effects on DA neurons, the R(+) enantiomer was more potent, and neither enantiomer produced long-term effects on 5-HT neurons. By contrast, in behavioral studies, both enantiomers increased mouse locomotor activity, but the S(-) enantiomer was more potent, which suggests that methcathinone's neurotoxic and locomotor stimulant effects may be separable. Additional studies were done with rats, because mice are often refractory to 5-HT neurotoxicity induced by amphetamines. In the rat, both enantiomers produced toxic effects on DA neurons, only S(-)-methcathinone produced toxic effects on 5-HT neurons, and both enantiomers produced comparable locomotor stimulant effects. Together, these results indicate that: 1) Methcathinone has the potential to damage DA and 5-HT neurons; 2) Methcathinone neurotoxicity is enantiomer and species dependent; 3) Methcathinone's neurotoxic and locomotor stimulant effects are dissociable in mice but not rats; and 4) N-methylation confers 5-HT toxic activity onto cathinone, the N-desmethyl derivative of methcathinone, which is known to lack 5-HT neurotoxic activity.

Animals↗
PubMed1996

Treating dental phobic patients in the Israeli Defense Force.

The present study reports the results of the Israeli Defense Force clinic for dental phobic patients 14 months after its establishment. Thirty four soldiers (26 men, 8 women) attended the clinic, their ages ranged from 19 to 46 years. The patients were asked to complete Corah's Dental Anxiety Scale (DAS), prior to their first and each subsequent visit to the clinic. A full dental examination, including radiographs, was carried out on each patient, and the DMFT was recorded. The Tell, Show, Do, technique (21 patients), the use of nitrous oxide/oxygen sedation (5), behavioural relaxation techniques (4), and hypnosis (1) were used. Most patients required four sessions or more for treatment. The mean DAS total scores significantly decreased after each visit, as did the mean scores for each question. The mean DMFT, and the D component, were higher than the scores reported previously in Israeli soldiers, suggesting an association between dental phobia, avoidance of dental treatment and higher dental disease. Alleviating anxiety by rational explanation may not be sufficient in all phobic patients.

Adult↗
PubMed1996

Use of the modified technique of ultrafiltration in pediatric open-heart surgery: a prospective study.

The use of cardiopulmonary bypass (CPB) in children is associated with significant morbidity due to the accumulation of an excessive amount of water. This can be decreased by massive diuresis, peritoneal dialysis, or conventional ultrafiltration technique (CUF) during bypass. However, we were dissatisfied with their effect on the outcome of our young patients, and recently began to use the modified technique of ultrafiltration (MUF) with good results. MUF was carried out for 15 min after completion of CPB to a hematocrit of 40%. Eighty patients were equally divided into two groups--MUF (group A) and control (group B)--and prospectively studied. There was one death in group A and two deaths in group B. The chest was left open in one patient in group A and in three patients in group B. At the end of MUF, the cardiac size was smaller, performance was better, and systemic blood pressure was higher in group A. Hematocrit levels in the two groups were similar during preoperative and CPB time, but post-CPB hematocrit in group A was significantly higher, 39.4% mean (range 35-50) vs. 28.5 (range 22-38) in group B (P <0.05). Blood loss was 10.56 ml/kg per 24 h (2-48.7) in group A vs. 20.8 (4.5-105.6) in group B (P <0.05). Blood transfused was 7.2 ml/kg per 24 h (0-29) in group A vs. 17.3 (3.1-49) in group B (P <0.05). Colloids transfused were 16.7 ml/kg per 24 h (0-64) in group A vs. 27.5 (0-58.6) in group B (P <0.05). No significant difference was found in urine output or the use of diuretics between the two groups. MUF results in better hemodynamic status in children, with the added advantage of less transfused blood and blood products. We believe that the use of accepted surgical techniques in combination with MUF will further improve the outcome of complex cardiac malformations.

Blood Loss, Surgical↗