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Biomedical subjects

P Klein

Publications and source records attributed to P Klein.

At least 73 records · Page 4Linked to original sources
PubMed1999

Ketanserin, an antagonist of 5-HT2A receptor of serotonin, inhibits testosterone secretion by rat Leydig cells in vitro.

The effect of ketanserin, an antagonist of 5-HT2A receptor of serotonin, added to the culture medium, on basal and LH-stimulated testosterone secretion was studied in primary cultures of adolescent rat Leydig cells. Ketanserin decreased the basal secretion of testosterone but showed an insignificant influence on the LH-stimulated process. It can be concluded that ketanserin may affect the testosterone-secreting cells by an indirect action at the vascular level as well as directly at the level of Leydig cells, at least in adolescent rats, leading to down-regulation of the basal testosterone secretion.

Animals↗
PubMed1999

Best of both worlds: stainless steel and nickel titanium.

The integration of the Quantec (0.06 taper 0.25-mm tip) rotary NiTi file and the standard stainless steel K-file (ISO 0.02 taper) synergistically simplifies instrumentation of the canal. The rotary NiTi file is primarily used to flare the coronal and midportion of the canal. Its flexibility enables clinicians to do so without ledging and perforation. Because of its effective cutting ability, the stainless steel file is used to clean and shape the apical area of the canal and blend the apical portion into the flare. Ultimately, this simplifies the obturation process. When familiar with this technique, dentists may find it easier to work with sequential tapers offered in the Quantec series of instruments. This series has a of tapers from 0.02 to 1.2. Understanding the crown-down concept and using quality and reliable instruments facilitates improved productivity.

Dental Instruments↗
PubMed1998

Immunostimulatory effects of dimerized lysozyme (KLP-602) on the nonspecific defense mechanisms and protection against furunculosis in salmonids.

Utilization of natural immunostimulants in fish culture offers a wide range of attractive methods for inducing and building protection against diseases. Lysozyme is an enzyme with bacteriolytic properties and is ubiquitous in its distribution among living organisms. This enzyme has antiviral, antibacterial and anti-inflammatory properties. In nature, lysozyme is found as a monomer. Lysozyme dimer is significantly less toxic than its monomer, and its high biological activity has been ascertained in cases of both viral and bacterial infections. In our study, we examined the influence of dimerized lysozyme (KLP-602) on the nonspecific cellular and humoral defense mechanisms and protection against furunculosis in rainbow trout (Oncorhynchus mykiss). We have analyzed the immunomodulatory effects of KLP-602 after experimental infection by Aeromonas salmonicida. Application of dimerized lysozyme (KLP-602) by injection stimulated the cellular and humoral defense mechanisms and provided protection against furunculosis. By contrast, mortality rate was reduced to 45% (one injection) and 25% (three injections) using 10 or 100 microg/kg KLP-602. Mortality in the untreated control group was 85%.

Adjuvants, Immunologic↗
PubMed1998

Homeopathic vs conventional treatment of vertigo: a randomized double-blind controlled clinical study.

OBJECTIVE: To compare the efficacy and safety of a homeopathic remedy (Vertigoheel, Heel Inc, Albuquerque, NM) vs betahistine hydrochloride (active control) in the treatment of patients with vertigo of various origins in a confirmative equivalence trial. DESIGN: Randomized (1:1) double-blind controlled clinical trial. SETTING: Fifteen study centers (general practice) in Germany between November 1995 and November 1996. SUBJECTS: A total of 119 patients with vertigo of various origins (from whom 105 patients could be analyzed as intended per protocol). MAIN OUTCOME MEASURES: Frequency, duration, and intensity of vertigo attacks. RESULTS: Both homeopathic and conventional treatments showed a clinically relevant reduction in the mean frequency, duration, and intensity of the vertigo attacks. The therapeutic equivalence of the homeopathic remedy and betahistine was established statistically. CONCLUSIONS: Concerning the main efficacy variable, therapeutic equivalence between the homeopathic remedy and betahistine could be shown with statistical significance (confirmative analysis). Both remedies reduced the frequency, duration, and intensity of vertigo attacks during a 6-week treatment period. Also, vertigo-specific complaints were significantly reduced in both treatment groups.

Adolescent↗
PubMed1998

Reduced TNFalpha and IL-6 production in patients who mount a preoperative acute phase response.

BACKGROUND/AIMS: In some patients postoperative infective complications are related to a reduced resistance to the operative trauma and the perioperative microbiological challenge. To investigate preoperative alterations in the immune responses in patients who had mounted an acute-phase response before the operation, we measured the capacity of tumor necrosis factor alpha and interleukin-6 production in whole blood. PATIENTS/METHODS: Serum concentrations of C-reactive protein, alpha1-antitrypsin, albumin, and prealbumin were measured in 89 patients submitted for major abdominal surgery on their admission to hospital. RESULTS: In 23 patients (26%) we found concentrations of at least one, and in 16 patients (18%) of two or more of these variables beyond the reference range. Patients who mounted an acute-phase response released 37% less TNFalpha (1339 vs. 848 pg/ml) and 31% less IL-6 (24293 vs. 16900 pg/ml) when whole blood was stimulated with lipopolysaccharide 0.5 microg/ml. CONCLUSION: Patients who mount an acute-phase response before operation may thus have a downregulated immune response at the level of proinflammatory cytokines. This is likely to alter their resistance to invasive micro-organisms in the perioperative period.

Acute-Phase Reaction↗
PubMed1998

Increased sensitivity of factor IX to phenprocoumon as a cause of bleeding in a patient with antiphospholipid antibody associated thrombosis.

We report one patient who presented with a spontaneous bleeding complication under phenprocoumon therapy. Oral anticoagulation was initiated due to deep-vein thrombosis which was attributed to an antiphospholipid antibody syndrome. Coagulation analysis revealed a strong and selective reduction of factor IX (F IX) activity to 1%, whereas the other vitamin K-dependent factors (II, VII, X), the prothrombin time and International Normalized Ratio (INR) were within the therapeutic range. After withdrawal of phenprocoumon, all vitamin K-dependent factors including F IX normalized. Because the patient suffered from a recurrence of thrombotic events, he was re-exposed to phenprocoumon and the disproportionate decline of F IX was observed again. These findings indicate an increased sensitivity of F IX to vitamin K antagonists, representing an uncommon mechanism associated with bleeding complications under oral anticoagulant treatment.

Adult↗
PubMed1998

HOX homeobox genes exhibit spatial and temporal changes in expression during human skin development.

The spatial and temporal deployment of HOX homeobox genes along the spinal axis and in limb buds during fetal development is a key program in embryonic pattern formation. Although we have previously reported that several of the HOX homeobox genes are expressed during murine skin development, there is no information about developmental expression of HOX genes in human skin. We have now used reverse transcriptase polymerase chain reaction, in conjunction with a set of degenerate oligonucleotide primers, to identify a subset of HOX genes that are expressed during human fetal skin development. In situ hybridization analyses demonstrated that there were temporal and spatial shifts in expression of these genes. Strong HOXA4 expression was detected in the basal cell layers of 10 wk fetal epidermis and throughout the epidermis and dermis of 17 wk skin, whereas weak signal was present in the granular layer of newborn and adult skin. The expression patterns of HOXA5 and HOXA7 were similar, but their expression was weaker. In situ hybridization analysis also revealed strong HOXC4 and weaker HOXB7 expression throughout fetal development, whereas HOXB4 was expressed at barely detectable levels. Differential HOX gene expression was also observed in developing hair follicles, and sebaceous and sweat glands. None of the HOX genes examined were detected in the adult dermis.

Adult↗
PubMed1998

Activation of the locus coeruleus after amygdaloid kindling.

PURPOSE: Substantia nigra (SN) and locus coeruleus (LC) neurons are implicated in the propagation and suppression of amygdaloid seizures. Both structures are activated concomitant with amygdaloid seizure discharges. Their mechanisms of activation, however, remain to be elucidated. SN firing is not associated with the induction of Fos immunoreactivity (ir), a marker of excitatory neuronal activation. LC has not been studied. The purpose of this investigation was to determine if amygdala-kindled generalized seizures could induce Fos-ir in the LC. METHODS: Female Sprague-Dawley rats were killed after generalized seizures induced by amygdala electrical stimulation and stained by using Fos immunocytochemistry. The number of Fos-ir neurons was compared between 15 animals with generalized seizures and four implanted, unstimulated controls. RESULTS: LC-ir neurons were significantly (p < 0.05) more prevalent after seizures than in control animals. Their numbers correlated very highly with Fos-ir in the central nucleus of the amygdala (p < 0.0001). No Fos induction was observed in LC in controls or in the SN in either group. CONCLUSIONS: Amygdala-induced generalized seizures result in Fos-ir in the LC but not in the SN. This is consistent with different mechanisms of activation possibly involving disinhibition in the SN and direct excitation in the LC.

Amygdala↗
PubMed1998

Hormonal effects on epilepsy in women.

Some female gonadal and adrenal steroid hormones and their related pituitary peptides have neuroactive effects that can influence seizures. These effects may play a significant role in the pathophysiology of epilepsy, the pattern of seizure occurrence, therapeutic interventions using naturally occurring hormones, and the development of hormone-based neuroactive synthetic analogues with potent antiepileptic properties.

Adrenocorticotropic Hormone↗
PubMed1998

Identification, functional characterization, and developmental expression of two nonallelic parathyroid hormone (PTH)/PTH-related peptide receptor isoforms in Xenopus laevis (Daudin).

Complementary DNAs encoding two nonallelic PTH/PTH-related peptide (PTHrP) receptor (PPR) isoforms, xPPR-A and xPPR-B, were isolated from a kidney complementary DNA library of the tetraploid African clawed frog Xenopus laevis. Both isoforms differ in their coding region by 19 amino acids, and lack the region corresponding to the mammalian exon E2. When expressed in mammalian COS-7 cells, both receptor isoforms bound radiolabeled PTH-(1-34) and PTHrP-(1-36) analogs with comparable affinity, and both unlabeled peptides equivalently stimulated the accumulation of cAMP. xPPR-A also mediated inositol phosphate turnover in COS cells and stimulated channel-mediated current changes in voltage clamp experiments after injection into oocytes. Using ribonuclease protection analysis, significant xPPR-A messenger RNA expression was first detected in neurula stage embryos, which subsequently increased approximately 30-fold during tadpole development. Expression reached a maximum at the metamorphotic climax, when isoform B also became detectable at significant levels, and subsequently declined in postmetamorphotic froglets. In the adult frog, xPPR-A was prominently expressed in lung, brain, small bowel, and skin, whereas isoform B was highest in lung, heart, and brain. Using an xPPR-A antisense riboprobe for in situ hybridization, expression appeared during metamorphosis at all sites of chondrogenesis, specifically in the maturing zone of the amphibian growth plate. xPPR-A expression was also seen in a subpopulation of mononuclear cells, possibly representing osteoblasts that line perichondral bone and diaphyseal bone trabeculae. Our findings suggest that xPPRs serve a prominent role in amphibian skeletal development and possibly other functions during embryonal and early larval development.

Aging↗
PubMed1998

Testosterone versus testosterone and testolactone in treating reproductive and sexual dysfunction in men with epilepsy and hypogonadism.

Antiepileptic drug-induced reductions in serum levels of biologically active testosterone and elevations in serum estradiol (E2) may contribute to sexual dysfunction among men with epilepsy. Treatment using a combination of testosterone and the aromatase inhibitor testolactone may have significantly better effects on sexual function and also seizure frequency than testosterone alone.

Adult↗
PubMed1998

The ontogeny of long-term memory over the first year-and-a-half of life.

This research documents the development of long-term memory in human infants from 2 months through the end of the first year-and-a-half of life. In the initial study phase, we trained 6- to 18-month-old human infants in an operant task and tested them after increasing delays until they exhibited no retention for 2 successive weeks. In the second phase, their data were combined with data previously obtained from 2- to 6-month-olds in an equivalent task. The resulting function revealed that the duration of retention increases monotonically between 2 and 18 months of age. This increase was not due to age differences in original learning. This is the first systematic analysis of the course of long-term memory across an extended period of infant development that is based on standardized parameters of training and testing. It provides a reference function against which measures of retention from infants of different ages that are obtained in different memory tasks with different parameters can be meaningfully compared.

Age Factors↗
PubMed1998

[How can the prognosis of acute mesenteric artery ischemia be improved? Results of a retrospective analysis].

AIM: Acute mesenteric ischemia is difficult to diagnose and is combined with a high mortality. In a retrospective analysis it was investigated how to improve the poor prognosis of the disease. PATIENTS AND METHODS: Between January 1988 through December 1994 a total of 46 patients were operated on for acute mesenteric ischemia. Mesenteric artery occlusion was present in three quarters of the cases (n = 35). These were analysed according to symptoms, diagnosis, mechanism of occlusion, operative procedure and prognosis. Distribution of gender was almost balanced (19 women, 16 men) with a median age of 70.5 years. RESULTS: Embolic arterial occlusion was predominant (n = 22). Most frequently, the superior mesenteric artery was exclusively concerned (n = 22). Serum levels of lactate and leucocytes were preoperatively elevated in over 90% (median values: lactate 53 U/l, leucocytes 15050/ml). In 16 patients diagnosis was made on the ground of clinical parameters and/or angiography, but 19 patients were not diagnosed until operation. 19 patients were operated within 6 hours, 12 patients within 24 hours after admission (> 24 hours: n = 4). Vascular reconstructive procedures only, such as thrombectomy and/or aortomesenteric bypass were performed in 9 cases, in a further 7 cases combined with bowel resection. Bowel resection alone was done in 7 patients, 12 patients had only diagnostic laparotomy. 13 patients survived, 10 of them had been treated with vascular reconstruction. CONCLUSION: Acute mesenteric ischemia ought to be suspected in every patient with uncertain abdominal pain, because only early diagnosis can improve prognosis. Measurement of serum lactate is diagnostically helpful, although not proving. In case of elevated lactate levels and uncertain abdominal symptoms angiography of the mesenteric vessels should be performed early. At operation, blood flow in the mesenteric arteries should be restored whenever possible.

Acute Disease↗
PubMed1998

Computed tomographic grading is useful in the selection of patients for nonoperative management of blunt injury to the spleen.

Although nonoperative management of blunt splenic injury (NMBSI) has an established role in the overall management of adult patients with blunt splenic injury, the criteria by which patients are selected continue to be debated. The purpose of this study is to establish the effectiveness of a defined set of criteria that includes CT grading for the selection of patients for NMBSI by examining the outcomes of patients managed in this manner 1 year before with those 1 year after the implementation of this specific set of selection criteria. All patients hospitalized at St. Joseph Mercy Hospital over the time period April 1994 through July 1996 with blunt splenic injury were included. Patients who died in the Emergency Department were excluded. Patients admitted from April 1994 through April 1995 composed Group I, those treated before the specific selection criteria, whereas those admitted from July 1995 through July 1996 composed Group II, those treated after the implementation of selection criteria. The two groups were compared with respect to demographic parameters, Injury Severity Score, mechanism of injury and length of stay. Outcomes were compared between these two groups. Those patients successfully managed without operation were further compared with those for whom NMBSI was unsuccessful. A total of 57 patients met the criteria for study entry, 28 from Group I and 29 from Group II. There were no significant differences between these two groups with respect to age, sex, mechanism of injury, Injury Severity Score, or length of stay. Nine of 27 in Group I required immediate operation; 19 were initially managed nonoperatively. Four of 19 required delayed laparotomy for bleeding, and all required splenectomy. Between patients successfully managed nonoperatively and those requiring delayed operation, the only significant difference was CT grade (1.47 vs 3.5; P = 0.0001). In Group II, after the implementation of selection criteria that included CT grade, no patient required delayed operation. Eleven underwent immediate operation, whereas 18 were successfully managed nonoperatively. We conclude that, in the hemodynamically stable patient without clinical indication for laparotomy, CT grading of the splenic injury is a reliable criterion by which patients may be selected for nonoperative management.

Adolescent↗
PubMed1998

[Osteopathy and chiropractic].

Osteopathy and chiropractic represent two challenging domains with a specific degree of multiplicity and complexity. This makes a complete appraisal difficult and impossible to appreciate in one single analysis. These disciplines exist since more than one century. An hermeneutic approach permits to understand their genesis but indicates also the nonsense of trying to transfer and apply earliest principles nowadays. It seems that most, but not all, practicing clinicians take into account recent developments in physiology, biomechanics and pathophysiology. Clinical studies and especially their meta-analyses on base of precise criteria permit to clarify the indications, therapeutic efficiency as well as socio-economic advantages. The meta-analyses point also at the poor quality of most clinical studies even if in the last years an improvement can be noted. Fundamental studies exist in both domains revealing interesting information that have permitted to reject several preconceived ideas and to clarifs others. Research topics as the morphology of the intervertebral disk before and after application of a manipulative technique are discussed. Results of experimental determination of global and segmental amplitudes in the cervical and in the lumbar spine during a manipulation in healthy subjects are reported. Finally the necessity but also the difficulties inherent to research studies in osteopathy and in chiropractic will be discussed.

Chiropractic↗
PubMed1998

[Reconstruction of incisional hernias with defined tensiometrically controlled tension--a possibility for anatomically correct reconstruction of the abdominal wall].

The repair of incisional hernias of the abdominal wall is characterized by high rates of recurrence if arbitrary tension is applied. A rationale for selecting the appropriate reconstruction technique as defined by intraoperative tension measurements has proven effective and successful. Here, the inlay/onlay technique tolerates up to 3.5 kilopounds (kp). Our results show that using this technique, complete reconstruction is possible in 65% of cases with a recurrence rate of 2.3%.

Cicatrix↗